This is the official thesis format for Masters/Bachelors thesis for NIT Trichy students. This in absolute compliance with the guidelines issued by the Office of Dean Academic.
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\begin{document}
\title{Manufacture of Ethylene: Process and Plant Design}
\author{Shubham Bobde \& Shibashish Devidutta Jaydev}
\date{\today}
\maketitle
\pagenumbering{roman}
\chapter*{abstract}
\addcontentsline{toc}{part}{ABSTRACT}
Ethylene, scientifically known as Ethene, is one of the industrial relevant petrochemicals and a acts a feed stock for a large number of commercial chemicals being produced. The ability to be easily polymerized renders ethylene the quality to be easily converted to polyethylene, which in turn is an economically important product. Ethylene is so widely used in the chemical industry that the estimated usage of Ethylene in the year of 2016 was marked at around 160 million tonnes. Taking into due considerations the importance and the increasing demand of ethylene, this plant design project is an investigation into the nuances of the industrial ethylene production. It will explore the various methods available for manufacturing Ethylene, decide on the most relevant method and delve into the design of a suitable chemical plant. The project will make an effort to understand the bottlenecks encountered during the production and then suggest suitable, plausible design variation to overcome the bottlenecks.
\newpage
\chapter*{Acknowledgements}
\addcontentsline{toc}{part}{ACKNOWLEDGEMENTS}
We would firstly like to extend our heartiest thankfulness to our esteemed guide Dr. Prof. Anantharaman for inspiring us throughout the project and for his sustained interest, guidance and support. He has been thoroughly instrumental in showing us the right direction at all points in time. We also wish to thank Dr. N. Samsudeen for occasionally guiding us in the absence of Prof. Anantharaman. We would like to take this opportunity to thank our esteemed Director, Dr. Mini Shaji Thomas and respected Head of Department, Prof. Sivashanmugam for facilitating the resources which were employed for the completion of this project. \\
Needless to mention, this project could not have been completed without the crucial help of Mr. Venkatesh Sowdhill, our final year project coordinator. He has been greatly kind in giving us ample amount of time to clear several doubts. We would also like to thank the non-teaching staff of the department who have been instrumental in providing us with field data regarding various chemicals.
\tableofcontents
\newpage
\addcontentsline{toc}{part}{LIST OF TABLES}
\listoftables
\newpage
\addcontentsline{toc}{part}{LIST OF FIGURES}
\listoffigures
\mychapter{1}{CHAPTER 1\quad INTRODUCTION}
\pagenumbering{arabic}.
\section{Motivation for selecting ethylene}
The motive behind the selection of Ethylene lies in the huge economic value of the chemical. Apart the economical value only, the multitude of ways in which it can be employed as a feed stock is also a major reason for the selection. In spite of having a very simple structure, what makes Ethylene an interesting subject of study is the large scale requirement of the same. The easy chemical transformation of Ethylene into ethanol and polyethylene makes it even more demanding and valuable. The global growth rate of demand is around 3.5\%, forecast over the next 5 years. The current capacity of world scale plants is around 1 million tons per year up from the 300 thousand tons per year world scale plants of the late 70s to early 80s. The clearly indicated growing demands calls for a thorough study of the production processes.
\section{Structure and physical properties}
Ethylene is the simplest unsaturated organic chemical, with the chemical form $CH_2=CH_2$. The IUPAC name of the chemical compound is Ethene.
\subsection{Structure}
This hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond. All six atoms that comprise ethylene are coplanar. The molecule is also relatively rigid: rotation about the C-C bond is a high energy process that requires breaking the π-bond. Ethylene is a colorless gas with a sweet odor and taste. It is lighter than air. The π-bond in the ethylene molecule is responsible for its useful reactivity. The double bond is a region of high electron density, thus it is susceptible to attack by electrophiles.
\begin{figure}[ht]
\centering
\includegraphics[width=0.3\columnwidth]{str.png}
% some figures do not need to be too wide
\caption{
\label{fig:exp_plots}
2-D structure of Ethylene showing the bond degrees and the angles.
}
\end{figure}
\begin{figure}[ht]
\centering
\includegraphics[width=0.3\columnwidth]{str1.png}
% some figures do not need to be too wide
\caption{
\label{fig:exp_plots}
3-D structure of Ethylene.
}
\end{figure}
\subsection{Properties}
Few relevant properties of Ethylene are as follows:
\begin{itemize}
\item Molar Mass: 28.05 $g/mol$
\item Appearance: Colorless
\item Density 1.178 $kg/m^3$ at 15 $\degree$
\item Solubility in water 2.9 mg/L
\item Melting Point 104 K
\item Boiling Point 169.5 K
\item Solubility in Ethanol 4.22 mg/L
\item Critical Temperature 282.65 K
\item Critical Pressure 50.5 atm
\item Flash Point 137 K
\item Autoignition temperature 815.9 K
\item Standard molar enthalpy for formation +52.47 $ kJ/mol$
\item Standard molar entropy 219.32 $J/K/mol$
\end{itemize}
\section{Major Uses}
\begin{itemize}
\item In the United States and Europe, approximately 90\% of Ethylene is used to produce Ethylene oxide, Ethylene dichloride, Ethyl benzene and Polyethylene.
\item The largest outlet, accounting for 60\% of ethylene demand globally, is polyethylene. Low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) mainly go into film applications such as food and non-food packaging, shrink and stretch film, and non-packaging uses. High density polyethylene (HDPE) is used primarily in blow moulding and injection moulding applications such as containers, drums, household goods, caps and pallets. HDPE can also be extruded into pipes for water, gas and irrigation, and film for refuse sacks, carrier bags and industrial lining.
\item The next largest consumer of ethylene is ethylene oxide (EO) which is primarily used to make ethylene glycol. Most monoethylene glycol (MEG) is used to make polyester fibres for textile applications, PET resins for bottles and polyester film. MEG is also used in antifreeze applications. Other EO derivatives include ethyoxylates (for use in shampoo, kitchen cleaners, etc), glycol ethers (solvents, fuels, etc) and ethanolamines (surfactants, personal care products, etc).
\item Other ethylene derivatives include alpha olefins which are used in LLDPE production, detergent alcohols and plasticizer alcohols; vinyl acetate monomer (VAM) which is used in adhesives, paints, paper coatings and barrier resins; and industrial ethanol which is used as a solvent or in the manufacture of chemical intermediates such as ethyl acetate and ethyl acrylate.
\item Ethylene also serves as a hormone in plants. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, and the abscission (or shedding) of leaves. Commercial ripening rooms use "catalytic generators" to make ethylene gas from a liquid supply of ethanol.
\end{itemize}
\begin{figure}[H]
\centering
\includegraphics[width=0.8\columnwidth]{use1.png}
% some figures do not need to be too wide
\caption{
\label{fig:use1}
Clockwise from the upper right: its conversions to ethylene oxide, precursor to ethylene glycol; to ethyl benzene, precursor to styrene; to various kinds of polyethylene; to ethylene dichloride, precursor to vinyl chloride.
}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=0.65\columnwidth]{use.png}
% some figures do not need to be too wide
\caption{
\label{fig:use}
Pie chart showing the comparison of the produce of various chemicals from Ethylene.
}
\end{figure}
\section{Production Processes }
The various commercial production processes that can be employed to produce Ethylene are as follows:
\subsection{Methanol to Olefin Process}
The Methanol to Hydrocarbons process was discovered at Mobil Oil in 1977. This process is used to convert methanol to products such as olefins and gasoline. The methanol can first be obtained from coal or natural gas. In the Methanol to Olefins (MTO) process, the methanol is then converted to olefins such as ethylene and propylene. The olefins can be reacted to produce polyolefins, which are used to make many plastic materials.\\\\
Critical to the successful application of the MTO process are acidic zeolite catalysts, which are discussed in detail on the zeolites page. Without these catalysts, the chemical reactions involved in the MTO process would be too slow for the process to be economically feasible.\\\\
The conversion of methanol to olefins on acidic zeolites takes place through a complex network of chemical reactions. The distribution of products and thus the “selectivity” depends on the temperature, among other factors. Selectivity is a measure of the amount of one product produced relative to others when the possibility to form multiple products exists. Selectivity depends on temperature through the Arrhenius law for the different rate constants.
\begin{figure}[ht]
\centering
\includegraphics[width=0.65\columnwidth]{block.jpg}
% some figures do not need to be too wide
\caption{
\label{fig:use}
Block diagram for the Methanol-to-Olefin process.
}
\end{figure}
\begin{figure}[ht]
\centering
\includegraphics[width=0.65\columnwidth]{pfd_mto.png}
% some figures do not need to be too wide
\caption{
\label{fig:use}
Process flow diagram for the Methanol-to-Olefin process.
}
\end{figure}
\subsection{Ethylene from renewable sources}
Ethanol extracted from biological sources can be used to used to produce ethylene by use of dehydration process. This is normally employed in highly developed countries where the hydrocarbon resources are minimal. ~\cite{1}
\begin{equation}
\ch{C2H5OH <-> C2H4 + H2O}
\end{equation}
Due to the high purity of ethylene product required (99.96\%), nearly all of the byproducts must
be removed from the final product stream. These two factors form the basis of this plant design:
a high temperature reactor and an intricately designed separations train with product purity as the
main goal.
\begin{figure}[H]
\centering
\includegraphics[width=0.9\columnwidth]{bioblock.png}
% some figures do not need to be too wide
\caption{
\label{fig:bioblock}
Block flow diagram for the production of Ethylene from Ethanol }
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=0.9\columnwidth]{bioethylene.PNG}
% some figures do not need to be too wide
\caption{
\label{fig:bioethylene}
Process flow diagram for the production of Ethylene from Ethanol }
\end{figure}
\newpage
\subsection{Steam Cracking}
This is the most commonly used, industrially viable process used for the purpose of production of Ethylene from either light or heavy feed stock. Light feed stock normally consists of Natural Gas liquids whereas the heavy feed stock normally refers to Naphtha and Gas oils. Modern ethylene plants incorporate following major process steps : cracking compression and separation of the cracked gas by low temperature fractionation. The nature of the feed stock and
the level of pyrolysis severity largely determine the operating conditions in the cracking and
quenching section.
\begin{figure}[ht]
\centering
\includegraphics[width=1\columnwidth]{cap1.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:cap1}
Process flow diagram for the production of Ethylene by steam cracking}
\end{figure}
\newpage
\section{Process Selection}
Of all the processes that have been described above, the production of ethylene from renewable sources is something which is not economically feasible in the context of India. Besides, this process is only suitable for production of considerably low quantities of Ethylene. As the requirements of the petrochemical industry in India is much higher than the produce that can be obtained from renewable source, the process is not an apt one for a developing country such as India.\\\\
As for the production of Ethylene from using Methanol, there is continuation formation of the coke on the zeolites catalyst being used. This is a cost intensive process and could be a bottleneck for cost reduction. The process was developed only in 1990s by UOP and is still under its nascent stages as far the technology available in concerned. Also there is globally only one MTO plant in Norway, which is indication of the fact that it is not economically suited to the requirements of a developing nation such as India.\\\\
The only reason that looks viable in this scenario is the process of steam cracking. Some reasons for selecting the steam cracking process would be the following:
\begin{itemize}
\item The process is simple in principle, without the requirement of any catalyst or indicator making it easy to design and also cost friendly
\item Coke formed can be removed easily compared to the MTO process
\item Steam is a very widely available utility.
\item It is an effective way to convert heavy petrochemicals (undesired) to light and valuable petrochemicals (desired).
\item As Naphtha is a readily available feed stock unlike the ethanol form bio-sources, it is easy to start the process.
\item It is a well established and well-described process with readily available technical backup to facilitate the smooth design of the plant.
\end{itemize}
\section {Steam Cracking of Naphtha}
\subsection{Major sections}
The main sections that are usually present in the steam cracking process are as follows~\cite{2}:
\begin{itemize}
\item \textbf{Hot Section}: It consists of convection zone and radiant zone. In the convection zone, hydrocarbon feed stock
is preheated and mixed with steam and heated to high temperature. In the convection zone the
rapid rise in temperature takes place and pyrolysis reaction takes place. The addition of dilution
steam enhances ethylene yield and reduces the coking tendency in the furnace coils. The
production of the pyrolysis reaction consists of a wide range of saturated and unsaturated
hydrocarbons.
\item \textbf{Quenching Section}: To avoid subsequent reaction the effluent are fixed in their kinetic development by sudden
quench first by indirect quench by water to 400-450 \degree C in transfer line exchanger or quench
boiler. This is a large heat exchanger that is a bundle of metal tubes through which the gases pass
and around which is circulated water under pressure. The hot water produced is used to generate
steam for use in the plant. In the next step the quench is done by heavy product of pyrolysis
\item \textbf{Cold Section}: After compression, caustic scrubbing and drying the light effluents enter the cold section of the
unit which performs the separation of hydrogen to various concentration (ii) ethylene
containing 99.4\% (iii) 95\% propylene (iv) A C4 cut containing 25-50\% butadiene
(v) pyrolysis gasoline which is rich in aromatic hydrocarbons.
The complexity of the separation section of a cracker increases markedly as the feed changes
from ethane.
\end{itemize}
\subsection{Reactions involved in steam cracking}
The reactions involved in thermal cracking of hydrocarbons are quite complex and involve many
radical steps. The thermal cracking reaction proceeds via a free radical mechanism. Two types of
reactions are involved in the thermal cracking (i) primary cracking where the initial formation of
paraffin and olefin takes place (ii) secondary cracking reaction where light products rich in
olefins are formed. The total cracking reactions can be grouped as follows:
\begin{itemize}
\item Initiation Reaction
\item Propagation Reaction
\item Addition Reaction
\item Isomerization Reaction
\item Termination Reaction
\item Molecular crystallisation reaction.
\end{itemize}
\subsection{Generalized composition of the feed stock}
Naphtha are mixture of alkane, cycloalkanes, and aromatic hydrocarbons depending on the type
of oil from which the naphtha was derived. The group properties of these components greatly
influence the yield pattern of the pyrolysis products. A full range naphtha boiling range
approximately 20 to 200 \degree C would contain compound, with from 4-12 carbon atms. Short
naphtha boiling point range from 100-140 \degree C and long chain naphtha boiling point lies around
200-220 \degree C. The steam cracking of the naphtha yields wide variety of products, ranging from
hydrogen to highly aromatic heavy liquid fractions. The thermal stability of hydrocarbons
increases in the following order: parafins, naphthenes, aromatics. Yield of ethylene as well as
that of propylene is higher if the naphtha feed stock is rich in paraffins.
\newpage
\subsection{Constraints}
\begin{itemize}
\item Material properties: tube material properties limit the temperature that can be maintained in the furnace and thereby the feedstock conversion.
\item Controllability: It is difficult to control the process as it has large number of unit operations and processes taking place.
\item Scale: As the requirement for the ethylene is very high and steam cracking is the cheapest process, it is a constrain to keep up with the huge demand. The turbines and compressors being used need to developed of large sizes to meet the requirements.~\cite{3}
\end{itemize}
\begin{figure}[ht]
\centering
\includegraphics[width=0.9\columnwidth]{15_a_.png}
% some figures do not need to be too wide
\caption{
\label{fig:15}
Process flow diagram for the production of Ethylene from steam cracking of Naphtha with balanced flow streams }
\end{figure}
\newpage
\mychapter{2}{CHAPTER 2\quad MASS BALANCE}
To evaluate the mass balance across each process equipment, first we need to decide on the final process flow diagram of the whole process. The final process flow diagram of the process flow diagram is as shown below.
According to the data available from the MOL group, Hungary, we are able to determine the composition of the products being obtained from the steam cracking on naphtha in a fired tubular furnace. The typical composition of the product stream emerging from the furnace, assuming no mass of naphtha is accumulated in the furnace is shown in the table below ~\cite{4}.
\begin{table}[ht]
\caption{Composition of outlet stream of furnace} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Percetage(\%) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 1.03 \\
$CH_4$ & 15.35\\% inserting body of the table
$C_2H_2$ & 0.69 \\
$C_2H_4$ & 31.02\\
$C_2H_6$ & 3.42\\
$C_3H_6$, $C_3H_4$ & 16.21\\
$C_3H_8$ & 0.38\\
$C4$ & 9.54\\
$C5-C12$ & 22.36\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:nonlin} % is used to refer this table in the text
\end{tabular}
\end{table}\\
Certain assumptions that have been used for mass balance which has been carried out hereafter. The assumptions have been obtained through suitable reference from the industrial data. ~\cite{5} The assumptions are as follows:
\begin{itemize}
\item The percentage recovery from distillation unit has been taken to be 99\% and the percentage purity of the top stream has been assumed to be 99.5\%.
\item The percentage conversion of the acetylene in the hydrogenator has been assumed to 100\% as only front-end hydrogenation has been considered for the naphtha.
\item The overall recovery of ethylene has been taken as 97\%. This is the amount of ethylene that can be recovered with respect to the ethylene coming out of the furnace.
\end{itemize}
\section{Daily production output of ethylene}
The daily production output of ethylene has been fixed to be \textbf{500} metric tons/day.
As we assume 97\% recovery of the amount present with respect to the ethylene that is coming of the furnace, we have to calculate the amount of the naphtha that will be required for the purpose.
\begin{itemize}
\item Amount of ethylene finally needed: \textbf{500 metric tons/day}
\item Amount of ethylene coming out of the furnace: \textbf{500/0.97=515 metric tons/day}
\item Amount of naphtha required to produce this amount of ethylene
\textbf{515/0.3102=1660 metric tons/day}
\end{itemize}
\begin{figure}[ht]
\centering
\includegraphics[width=0.9\columnwidth]{ethylene_production.jpg}
% some figures do not need to be too wide
\caption{
\label{fig:pfd}
Simple process flow diagram for the production of Ethylene from steam cracking of Naphtha with the flow rates of every stream }
\end{figure}
\section{Mass balance across the furnace}
Naphtha going in is 1660 metric tons/day.\\
Product outflow has been shown in the table below, assuming no naphtha is lost in the process of coking.
\begin{table}[ht]
\caption{Amount of each component in outlet stream of furnace} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 17.098 \\
$CH_4$ & 254.81\\% inserting body of the table
$C_2H_2$ & 11.454 \\
$C_2H_4$ & 514.932\\
$C_2H_6$ & 56.772\\
$C_3H_6$, $C_3H_4$ & 269.086\\
$C_3H_8$ & 6.308\\
$C4$ & 158.364\\
$C5-C12$ & 371.176\\
$Total$ & 1660\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:products} % is used to refer this table in the text
\end{tabular}
\end{table}\\
The operating conditions which gives us the output product that we get in the table \ref{table:products} has been highlighted below.
\begin{itemize}
\item Temperature= 800-850 degree celsius
\item Steam Required= 0.5 kg/kg of naphtha
\item Residence time 0.1-0.5 seconds
\end{itemize}
The addition of the steam for the purpose of dilution ensures that we are able to achieve a near 100 \% conversion of naphtha since there is no coking taking place in the furnace.
\begin{figure}[ht]
\centering
\includegraphics[width=0.4\columnwidth]{Capture.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:pfdfurncae}
Streams coming out of the furnace }
\end{figure}
\newpage
\section{Mass balance across the DeC5-DeC12 unit}
The mass balance over the distillation column has been carried out using the basic mass conservation equation used in the distillation column, which are as follows.
\begin{equation}
F=D+R
\end{equation}
\begin{equation}
Fx_f=Dy_D+ R.x_R
\end{equation}
\begin{itemize}
\item Feed (F)= 1660 metric tons/day
\item $x_f$= (C1-C4 present in the feed)/total feed= (1.03+15.35+0.69+31.02+3.42+16.21+0.38)/100*1660/1660= 0.681
\item $y_D$= the purity of the top stream has been assumed to be 99.5 \%
\item $Dy_D$= the recovery has been assumed to 99 \%, hence the value of $Dy_D$ is valued to be 99/100*0.681*1660=1276.264
\item $D$ (distillates stream containing C1-C4)= 1282.678
\item $R$ = 377.322
\item $x_R$= 0.0341
\end{itemize}
Above shown are the model calculation which have been used for all the remaining distillation units namely the debutaniser, depropaniser and demethaniser.The distillate stream of one column acts as the feed for the next column.
\section{Mass balance across debutaniser}
\begin{table}[H]
\caption{Various parameters and their values across the debutaniser unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$F$ & 1282.678 \\
$x_f$ & 0.8725\\% inserting body of the table
$Dx_D$ & 1107.9638 \\
$x_D$ & 99.5 \% \\
$D$ & 1113.531\\
$R$ & 169.146\\
$x_R$ & 0.066\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:debutan} % is used to refer this table in the text
\end{tabular}
\end{table}
\section{Mass balance across depropaniser}
\begin{table}[ht]
\caption{Various parameters and their values across the depropaniser unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$F$ & 1113.531 \\
$x_f$ & 0.7526\\% inserting body of the table
$Dx_D$ & 829.67\\
$x_D$ & 99.5 \% \\
$D$ & 833.84\\
$R$ & 279.6921\\
$x_R$ & 0.03\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:demethan} % is used to refer this table in the text
\end{tabular}
\end{table}
\newpage
\section{Mass balance across the caustic wash unit}
The chemical reactions taking place in the caustic wash unit are as follows.
\begin{equation}
\ch{H2S(aq) + NaOH(aq) -> NaHS(aq) + H2O}
\end{equation}
\begin{equation}
\ch{NaHS(aq) + NaOH(aq) -> Na2S(aq) + H2O}
\end{equation}
\begin{equation}
\ch{CO2(aq) + NaOH(aq) -> NaHCO3(aq) + H2O}
\end{equation}
\begin{equation}
\ch{NaHCO3(aq) + NaOH(aq) -> Na2CO3(aq) + H2O}
\end{equation}
\begin{itemize}
\item Amount of $H_2S + CO_2$ which is left over at the end of three distillation can be evaluated as to be $1.03*1660*(0.99)^3 = 16.6$ metric tons/day.
\item Lets say that the conversion would requires X kgs of NaOH. All the X kg of NaOH will be flushed out in the outlet stream as the efficiency of the scrubber is assumed to be 100\%.
\end{itemize}
\begin{table}[ht]
\caption{Inlet parameters in the caustic wash unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$F$ & 833.84 metric tons/day\\
$x_f (C1-C2)$ & 0.975\\
$H_2S +CO_2 $ & 16.6\\
$NaOH$ & X metric tons/day\\
Net inlet $(F+NaOH)$ & 833.84 + X\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:inletcaustic} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[ht]
\caption{Outlet parameters in the caustic wash unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$Na_2S + 4H_2O + Na_2CO_3$ + unrecovered hydrocarbons & X+12.26 metric tons/day \\
Non-distillate Outlet & 28.892 metric tons/day\\
Distillate outlet (0.975*0.99*833.84/0.995) & 804.948 metric tons/day\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:inletcaustic} % is used to refer this table in the text
\end{tabular}
\end{table}
To calculate the net outlet we have assumed that the stream purity is 99.5 \% and the recovery of the required C1-C2 fractions is also 99 \%.
\begin{figure}[ht]
\centering
\includegraphics[width=0.6\columnwidth]{casutic.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:caustic}
A typical caustic scrubber unit}
\end{figure}
\newpage
\section{Mass balance across demethaniser}
The demethaniser is the unit which uses pressurised inputs within the distillation columns to keep the C1-C2 units in the form of liquid to facilitate the separation.
\begin{table}[ht]
\caption{Various parameters and their values across the demethaniser unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value (mton/day) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$F$ & 804.948 \\
$x_f$ & 0.31\\
$R$ & 560.18\\
$D$ & 244.768\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:debutan} % is used to refer this table in the text
\end{tabular}
\end{table}
\newpage
\section{Mass balance across the hydrogenator}
The reaction which is involved in the hydrogenator is as follows.
\begin{equation}
\ch{C2H2 + H2 -> C2H4}
\end{equation}
With the reference from the table presented below, it can be seen that when a front-end hydrogenator is operated on the $C_2H_2$ coming out of naphtha, the efficiency of the hydrogenator is assumed to be 100 \%.
\begin{figure}[ht]
\centering
\includegraphics[width=0.9\columnwidth]{table.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:table}
Table showing the conversion for all types of hydrogenation ~\cite{5} }
\end{figure}
\begin{itemize}
\item Amount of $C_2H_2$ that is to be converted is $0.69*0.99^5*1660=10.89$ metric ton/day.
\item Number of moles of acetylene to be removed is 10.89/26 = 0.42 metric ton moles.
\item Amount of hydrogen required is same as the amount of acetylene to be converted which is 0.42 metric ton moles/day which translates to 0.84 metric tons/day.
\item Amount of ethylene that is produced due to the reaction is 0.42*28= 11.76 metric tons/day.
\end{itemize}
\begin{table}[ht]
\caption{Amount of each component in outlet stream of furnace} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value (metric tons/day) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Inlet & 560.18\\
Amount of acetylene removed & 10.89 \\
Amount of Hydrogen supplied & 0.84 \\
Amount of ethylene produced & 11.73 \\
$Outlet$ & 561.02\\% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:dethan} % is used to refer this table in the text
\end{tabular}
\end{table}
Here the outlet exceeds the inlet only by the weight of hydrogen added as this converts the acetylene 100 \% into ethylene.
\section{Mass balance across deethaniser}
\begin{table}[ht]
\caption{Various parameters over the de-ethaniser unit} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Value \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$F$ & 561.89\\
$x_f$ & 0.894\\% inserting body of the table
$Dx_D$ & 497.5\\
$x_D$ & 99.5 \% \\
$D$ & 500\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:dethan} % is used to refer this table in the text
\end{tabular}
\end{table}
The distillate recovered from the ethaniser unit is the final product which is removed at the rate of 500 metric tons/day and has purity of 99.5 \% i.e 0.5 \% of it contains some remnant ethane which can't be separated.
\section{Overall Mass Balance}
\begin{table}[ht]
\caption{Mass balance across all streams} % title of Table
\centering % used for centering table
\begin{tabular}{c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameter & Amount (metric tons/day) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Feed into furnace & (+) 1660\\
Amount of Hydrogen added & (+) 0.84\\
Residue of DeC5-DeC12 & (-) 377.322\\% inserting body of the table
Residue of Debutaniser & (-) 169.146\\
Residue of Depropaniser & (-) 279.692\\
Outlet of the caustic remover & 28.892 \\
Residue of Demethaniser & (-) 244.768\\
2Residue of Deethaniser & (-) 61.02\\
Ethylene obtained finally & (-) 500\\
Net & 0.00\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:dethan} % is used to refer this table in the text
\end{tabular}
\end{table}
As the net is being obtained as 0.00, it is seen that net mass balance over the whole unit has been successfully obtained.
\newpage
\mychapter{3}{CHAPTER 3\quad ENERGY BALANCE}
The energy balance, in general, has to take care of the equilibrium between the net energy input and the net energy output of the system. In ideal cases, where there are no losses to the atmosphere, the energy output should be exactly same as the energy input. However, this is not possible in the real scenario. The major assumptions are made with respect to the heat capacity of the various components.
The following are the major assumptions which have been made during the energy balance:my
\begin{itemize}
\item The heat capacity of the hydrocarbon streams is assumed to be constant across all temperatures. This is attributed to the very low variation in the heat capacity with change in temperature.
\item The distillation columns being used as cryogenic distillation columns which implies that the heat is to be removed before the streams are allowed into the distillation column.
\item The reference temperature to calculate the enthalpy has been taken to be 273 K
\item Heat transfer over the caustic wash units has been treated as negligible.
\item In each distillate stream of every distillation column, the enthalpy due to the
\item Changes in the heat capacity of the component due to their presence in a mixture has been neglected.
\end{itemize}
\section{Methodology}
The inlet and the outlet enthalpies of each stream has been evaluated. The net enthalpy change happening over a unit has can be evaluated by the following equations:
\begin{equation}
H_i=mC_p(T_i-T_*)
\end{equation}
\begin{equation}
H_o=mC_p(T_o-T_*)
\end{equation}
\begin{equation}
\Delta H=H_o-H_i
\end{equation}
The difference in the enthalpy is supplied by the usage of any utility. \textbf {The nature of the utility and the specifications are discussed in the design part of the project}
\section{Energy balance over the furnace}
Key points taken into consideration in this energy balance are:
\begin{itemize}
\item Each component of the hydrocarbon stream is formed at a temperature of 700 degree Celsius, which is nearly the temperature at which the reaction is carried out.
\item The Naphtha stream is assumed to enter into the 180 degree Celsius, after passing through the transfer line heat exchanger.
\item The fuel used in natural gas which is found to have a calorific value of 12500 kcal/kg.
\end{itemize}
\begin{table}[ht]
\caption{Components and their enthalpies in the furnace} % title of Table
\centering % used for centering table
\begin{tabular}{c c c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & CP (kcal/kg/K) & $\Delta H X 10^3$ \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 17.098 & 0.242857143 & 2906.66\\
$CH_4$ & 254.81 & 0.528571429 & 94402.54\\% inserting body of the table
$C_2H_2$ & 11.454 & 0.402380952 & 3226.21 \\
$C_2H_4$ & 514.932 & 0.364285714 & 131307.66\\
$C_2H_6$ & 56.772 & 0.416666667 & 16558.5 \\
$C_3H_6$, $C_3H_4$ & 269.086 & 0.357142857 & 67271.5\\
$C_3H_8$ & 6.308 & 0.397619048 & 1755.726667\\
$C4$ & 158.364 & 0.397619048 & 44077.98\\
$C5-C12$ & 371.176 & 0.49 &
127199.492\\
Naphtha & 1660 & 0.495 & -147906 \\
Fuel & 105218.4 & & -1315230\\
Net & & & 0\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:products} % is used to refer this table in the text
\end{tabular}
\end{table}
As the net enthalpy over the furnace is seen to be zero, we can say that the energy quantities have been balanced over the furnace.
\section{Energy balance over the Transfer Line Heat Exchanger}
Key points in energy balance over this unit are:
\begin{itemize}
\item The inlet temperature of Naphtha is assumed to be 25 degree Celsius
\item The outlet temperature of Naphtha is taken to be 180 degree Celsius
\item The Naphtha is heated using the process to process heat transfer
\item The inlet enthalpy of Naphtha at 25 degree celsius is 1660*1000*(25-0)*0.495 = 20542500 kcal
\item The outlet enthalpy of Naphtha at 180 degree is 1660*1000*(180-0)*0.495= 147946000 kcal
\item The net enthalpy difference of Naphtha passing through the heat exchanger= 127363500 kcal
\item We are considering that the outlet stream of the furnace is at 700 degree Celsius.
\item The temperature of the outgoing hydrocarbon stream 700-127363500/1064508.384= 581 degree Celsius.
\end{itemize}
\begin{table}[ht]
\caption{Components and their parameter while passing through the transfer line heat exchanger} % title of Table
\centering % used for centering table
\begin{tabular}{c c c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & CP (kcal/kg/K) & $mC_p X 10^3$ \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 17.098 & 0.242857143 & 4.152371429\\
$CH_4$ & 254.81 & 0.528571429 & 134.8607714\\% inserting body of the table
$C_2H_2$ & 11.454 & 0.402380952 & 4.608871429 \\
$C_2H_4$ & 514.932 & 0.364285714 & 187.5823714\\
$C_2H_6$ & 56.772 & 0.416666667 & 23.655 \\
$C_3H_6$, $C_3H_4$ & 269.086 & 0.357142857 & 96.10214286\\
$C_3H_8$ & 6.308 & 0.397619048 & 2.508180952\\
$C4$ & 158.364 & 0.397619048 & 62.96854286\\
$C5-C12$ & 371.176 & 0.49 &
181.71356\\
Steam & 810 & 0.452 & 366.42\\
Total & 2470 & & 1064.580384 \\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}my
\newpage
\section{Energy balance over the quenching unit}
\begin{itemize}
\item The inlet temperature of the stream is 581 degree celsius
\item The outlet temperature of the stream is 250 degree Celsius
\item Referring to the table \ref{table:TLEs} 1064.58*1000*(581-250)= 352376107 kcal is the total amount of heat that is to be removed by the utility
\item The specifications of the utility across the cooling unit will be discussed in the design part.
\end{itemize}
\section{Energy balance over the cooling unit}
The key consideration in balancing the heat over the cooling unit are as follows:
\begin{itemize}
\item Heat of vaporisation of the steam is taken to be 539 kcal/kg
\item Heat of vaporisation of 83 kcal/kg
\item The inlet temperature of the stream is taken to be 581 degree Celsius and the outlet temperature is taken to be 30 degree 35 degree Celsius.
\item Subcooling is considered only for the process steam.
\item For the cracked hydrocarbon, only the stream consisting of C5-C12 is assumed to be condensed; however sub-cooling is not considered for the same.
\end{itemize}
\begin{table}[ht]
\caption{Components and their parameter while passing through the transfer line heat exchanger} % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Stream & Heat absorbed X $10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 892.7598571 \\
$CH_4$ & 28995.06586\\% inserting body of the table
$C_2H_2$ & 990.9073571\\
$C_2H_4$ & 40330.20986\\
$C_2H_6$ & 5085.825\\
$C_3H_6$, $C_3H_4$ & 20661.96071\\
$C_3H_8$ & 539.2589048\\
$C4$ & 13538.23671 \\
$C5-C12$ & 69848.4674\\
Steam & 544204.2857\\
Total & 725086.9774\\
Heat removed by utility & -725086.9774\\
Net heat & 0\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\section{Energy balance over the de-butaniser unit}
Keys points to be considered for the heat balance across the de-butaniser unit are as follows:
\begin{itemize}
\item The inlet temperature of the distillation unit is taken to 30 degree Celsius.
\item The operating temperature of the de-debutaniser is -10 degree Celsius in order to keep the butane in the liquid state.
\item The lower temperature of the de-butaniser is maintained with the help of a chilling train which a refrigerant in the form of a utility.
\item Heat balance over the de-butaniser unit and other distillation units are taken as per the following equation:
\begin{equation}
H(feed)+H(utility)= H(distillate) + H(residue)
\end{equation}
\item In the energy balance shown, it can be noted that the enthalpy of the distillate due to presence of small quantity has been neglected as this is a negligible quantity.
\item Similarly, the contribution of the small quantity of the top product in the enthalpy of the residue is also taken as negligible.
\end{itemize}
\begin{table}[ht]
\caption{Components in the feed and their parameter while passing through the de-butaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & CP (kcal/kg/K) & $H(feed)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 16.92702 & 0.242857143 & 123.3254314\\
$CH_4$ & 252.59058 & 0.528571429 & 4005.364911\\% inserting body of the table
$C_2H_2$ & 11.33946 & 0.402380952 & 136.8834814\\
$C_2H_4$ & 509.78268 & 0.364285714 & 5571.196431\\
$C_2H_6$ & 56.20428 & 0.416666667 &
702.5535\\
$C_3H_6$, $C_3H_4$ & 266.39514 & 0.3571 & 2854.233643\\
$C_3H_8$ & 6.24492 & 0.397 & 74.49297429\\
$C4$ & 156.78036 & 0.397619048 & 1870.165723\\
Total Enthalpy & & & 15338.2161\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[ht]
\caption{Components in the distillate stream and their parameter while passing through the de-butaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & $H(distillate)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 16.7577498 & -40.69739237\\
$CH_4$ & 250.0646742 & -1321.770421\\% inserting body of the table
$C_2H_2$ & 11.2260654 & -45.17154887\\
$C_2H_4$ & 504.6848532 & -1838.494822\\
$C_2H_6$ & 55.6422372 & -231.842655\\
$C_3H_6$, $C_3H_4$ & 263.7311886 & -941.8971021\\
$C_3H_8$ & 6.1824708 & -24.58268151\\
Total Enthalpy & &-4444.456623\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Components in the streams and their parameter while passing through the de-butaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & $H$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Feed & 15338.2161\\
Distillate & -4444.456623\\
Residue & -672.5567143\\
Heat removed by refrigerant utility & -20455.22943\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\newpage
\section{Energy balance across the de-propaniser unit}
Key points to be considered for the energy balance across the de-propaniser unit are as follows:
\begin{itemize}
\item The entering stream which is coming from the debutaniser is at a temperature of -10 degree Celsius.
\item The exiting stream which is coming out of de-propaniser is at -44 degree celsius, which also happens to be operating temperature of the depropaniser unit.
\end{itemize}
\begin{table}[H]
\caption{Components in the feed stream and their parameter while passing through the de-propaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & $H(feed)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & 16.7577498 & -40.69739237\\
$CH_4$ & 250.0646742 & -1321.770421\\% inserting body of the table
$C_2H_2$ & 11.2260654 & -45.17154887\\
$C_2H_4$ & 504.6848532 & -18338.494822\\
$C_2H_6$ & 55.6422372 & -231.842655\\
$C_3H_6$, $C_3H_4$ & 263.7311886 & -941.8971021\\
$C_3H_8$ & 6.1824708 & -24.58268151\\
Total Enthalpy & &-4444.456623\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Components in the distillate stream and their enthalpies while passing through the de-propaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & $ H(distillate)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$H_2S$, $CO_2$ & -177.2778412\\
$CH_4$ & -5757.631953\\% inserting body of the table
$C_2H_2$ & -196.7672669\\
$C_2H_4$ & -8008.483446\\
$C_2H_6$ & -1009.906605\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Components in various streams and their enthalpies in the de-propaniser unit}%title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & H $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Feed & -4444.456623\\
Distillate & -15150.1\\
Residue & -4430.2896\\
Heat removed by refrigerant utility & -15135.90009\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\section{Energy balance over the de-methaniser unit }
The key points taken into consideration while balancing the energy over the de-methaniser unit are as follows:
\begin{itemize}
\item As the methane is a liquid below -145 degree Celsius and $C_2$ products are liquid below -89 degree Celsius, we set the operating temperature of the de-methaniser unit somewhere in between.
\item The operating temperature of the de-methaniser column, operating with the help of a chilling train and a refrigerant is set to -100 degree celsius.
\end{itemize}
\begin{table}[H]
\caption{Components in the feed stream and their parameter while passing through the de-methanisr unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & Amount(metric-tons/day) & $H(feed)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$CH_4$ & 245.0883872 & -5700.055633\\% inserting body of the table
$C_2H_2$ & 11.0026667 & -194.7995942\\
$C_2H_4$ & 494.6416246 &
-7928.398612\\
$C_2H_6$ & 54.53495668 & -999.8075391\\
Total Enthalpy & & -14823.06138
\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Components in the distillate stream and their enthalpies while passing through the de-methaniser unit } % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & $ H(distillate)$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$CH_4$ & -12825.12518
\\% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Components in various streams and their enthalpies in the de-methaniser unit}%title of Table
\centering % used for centering table
\begin{tabular}{c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Hydrocarbon & $H$ $X 10^3$\\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Feed & -14823.06138\\
Distillate & -12825.12518
\\
Residue & -20166.48
\\
Heat removed by refrigerant utility & -18168.5438
\\
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:TLEs} % is used to refer this table in the text
\end{tabular}
\end{table}
\newpage
\mychapter{4}{CHAPTER 4\quad DESIGN OF EQUIPMENTS}
\section{Furnace Design}
The following are some of the design consideration for designing a furnace for the purpose of steam cracking
\begin{itemize}
\item Heaters shall be designed for uniform heat distribution
\item Multi-pass heaters shall be designed for hydraulic and thermal symmetry of all passes. The number of passes shall be minimized. Each pass shall be a single
circuit
\item Average heat flux density in the radiant section is normally based on single row of tubes with two nominal tube diameter spacing.
\item The maximum allowable inside film temperature for any process service shall not be exceeded in the radiant, shield, or convection sections.
\item minimum radiation loss 2.5\% the total heat input
\item Natural draft needs 25\% excess air when oil is the primary fuel and 20\% excess air
when fuel gas is the primary fuel. In case of forced draft operation, 20\% Excess air for fuel oil and 15\% Excess air for fuel gas
\item Heaters shall be designed such that a negative pressure of at least 0.10 inches of water (0.025 kilopascals) is maintained in the radiant and convection sections at maximum heat release with design excess air.
\item The flue gas dew point can be predicted, and the minimum tube-metal temperature can be kept high enough to prevent condensation, if the fuel's sulfur content has been correctly stated. (For estimated flue gas dew points with respect to sulfur content in fuel oil and gas
\item In a well-design heater, the radiant-section heat duty should represent more than 60\% to 70\% of the total heat duty
\item The bridge wall temperature should range between 800°C to 1,000°C.
\item Higher radiant flux means less heat transfer surface area for a given heat duty; hence, a smaller furnace.
\item The higher the film temperature, the greater is the tendency of the fluid (particularly
a hydrocarbon) to crack and deposit a layer of coke.
\item Heat-transfer fluids tend to degrade quickly at high film temperatures.
\item The coke layer acts as an insulator, retarding heat transfer, which could cause tube
overheating and lead to tube failure.
\item Also, a heavy coke deposit can restrict the flow through the coil, lowering the inside
heat transfer coefficient and further increasing the tube wall temperature.
\item The smallest firebox for a certain duty will obviously produce the cheapest design.
\item The flame impingement and consequent tube failure that could result can be avoided by specifying a minimum safe distance between burners and tubes, based on experience
\item Provision for thermal expansion shall take into consideration all specified operating
conditions, including short term conditions such as steam-air decoking.
\item The convection section tube layout shall include space for future installation of sootblowers.
or steam lancing doors.
\item The convection section shall incorporate space for future addition of two rows of
tubes.
\item When the heater is designed for fuel oil firing, soot-blowers shall be provided for
convection section cleaning.
\item Vertical cylindrical heaters shall be designed with maximum height to diameter ratio
of 2.75, where the height is the radiant section height and the tube circle diameter.
\item Shield sections shall have at least three rows of bare tubes.
\item Convection sections shall be designed to minimize flue gas bypass. Baffles may be
employed.
\item The minimum clearance from grade to burner plenum or register shall be 6 feet 6 inches (2.0 meters) for floor fired heaters.
\end{itemize}
\begin{figure}[H]
\centering
\includegraphics[width=0.9\columnwidth]{furnace_design.jpg}
% some figures do not need to be too wide
\caption{
\label{fig:furnace}
Rough 3-D sketch of a Furnace Design }
\end{figure}
\subsection{Design Steps}
\begin{itemize}
\item The length of the furnace tubes is taken to be 20 m and the diameter(OD) is taken to be 219 mm.
\item The centre to centre distance of the tubes placed inside the furnace is taken as 394 mm.
\item The total heat that is liberated by the fuel is, $Q_f$= 1315230000 kcal.
\item The radiant section area of a single can be calculated from the dimension of a single tube. Area =$2\pi rL$=2*3.14*219/2/1000*20= 13.75 $m^2$.
\item The radiant section heat flux is 920661000/1.09 = 844643199 $kcal/m_2/day$, as the basis for all the calculations has been taken to be a day.
\item The temperature of the gases above the bridge-wall has been approximately taken to be 900 degree Celsius.
\item The temperature of the gas above the bridge-wall is around 150 degree more than the bridge-wall temperature, and can be taken around 1900 degree Fahrenheit
\item The temperature of the tube surface to ensure maximum heat flux is taken to 200 degree Fahrenheit.
\item By use of the tube surface temperature (Ts) and the temperature of the gas above the bridge-wall, we can evaluate the heat flux through the radiant section, $q$ , by using the following equations.
\begin{equation}
\frac{\Sigma Q}{\alpha_{cp}A_{cp}f}= 2 * q
\end{equation}
\item Where, $\alpha_{cp}A_{cp}$ is the net cold surface area and $f$ is the overall exchange factor.
\item The value of $\frac{\Sigma Q}{\alpha_{cp}A_{cp}f}$ arrived at by use of the chart show in figure \ref{fig:furnacegraph}, is 70,000 $btu/hr/ft^2$.
\item Taking this amount on a daily basis and in the units of $kcal/day/m^2$, we get 70000*24*2.71= 4552800
\item Thus the value of $q$ is calculated to be 4552800/2=2276400 $kcal/m^2/day$
\begin{figure}[H]
\centering
\includegraphics[width=1.2\columnwidth]{graph.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:furnacegraph}
The graph showing the relationship between Tg, Ts and $\frac{\Sigma Q}{\alpha_{cp}A_{cp}f}$ }
\end{figure}
\item Th fuel being used is natural gas which has a calorific value of 12500 kcal/kg
\item The amount fuel required is, $m_{fuel}$ 1315230000/12500= 106 tons.
\item For natural gas, the air to fuel ratio maintained is taken to be, G'= 10:1.
\item Amount of air needed is 1060 tons.
\item Assuming 25\% of excess air is used, we need 1.25*1060 tons= 1325 tons.
\item We also require the usage of atomizing steam to be able to ensure easy mixing of the fuel with the air and burn quickly. However in this case, we will neglect the usage of atomising steam for the sake of convenience.
\item Amount of heat associated with the inlet air, $Q_{air}$= 1325*1000*0.25*(105-25)=26304600 kcal.
\item The amount of heat absorbed by the furnace wall is, $Q_w$= 2\%*$Q_f$ = 0.02*1315230000= 26304600 kcal.
\item The total heat absorbed by the tubes is, $\Sigma Q$ = $Q_f$+ $Q_{air}$-$Q_w$ = 1315230000+26304600-26304600= 1315230000 kcal/hr
\begin{equation}
N_{tubes}=\frac{\Sigma Q}{2\pi r L q}=\frac{1315230000}{2*3.14*20*0.1095*2267400*}=42
\end{equation}
\begin{equation}
A_{cp}= ctc* L* N = 42*0.394*42=695 m^2
\end{equation}
\item Where N=no. of tubes, L=length of tubes, ctc=centre to centre distance of the tubes.
\item Placing the tubes in a horizontal fashion within the furnace, we get height of the furnace required to just place the tubes would be, ctc*N= 0.394*42= 16.548 m.
\item Taking the clearance between the tubes and the furnace wall to be 0.22 meters, the total width of the furnace can be taken as L+2*clearance= 20.44m
\
\newpage
\end{itemize}
\begin{table}[H]
\caption{Various parameters and their values relating to the design of the furnace } % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameters & Values \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
length of a furnace tube(m) & 20\\
diameter of the furnace tube (mm) & 219\\
centre-to-centre distance of the tubes (mm) & 394 \\
heat exchange area of single tube ($m^2$) & 13.75 \\
tube surface temperature ($\degree F$) & 200\\
gas temperature over bridgewall ($\degree F$) & 1900\\
air to fuel ratio & 10:1\\
Calorific value of the fuel (kcal/kg) & 12500 \\
number of tubes & 42\\
cold plane area ($m^2$) & 695\\
Clearance b/w tubes and furnace wall($m$) & 0.22\\
Total width of the furnace($m$) & 20.44\\
\\% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:furnace data} % is used to refer this table in the text
\end{tabular}
\end{table}
\newpage
\section{Design of distillation column }
The considerations for design of the distillation column are as follows:
\begin{itemize}
\item A de-methaniser is being designed.
\item The operating pressure for the de-methaniser is 15 atm and the operating temperature is -100 \degree Celsius.
\end{itemize}
\subsection{Determination of number of trays}
\begin{itemize}
\item The calculation of the relative volatility is done using Raoult's law.
\begin{equation}
P_t=X_f.P_A+(1-X_f).P_B
\end{equation}
\item Here the $P_t$ is the total pressure which is equal to 15*760=11400 mm Hg
\item $X_f$, as evaluated in the mass balance section has been taken as 0.31
\item As the more volatile component that is to be removed is Methane, the vapour pressure of methane, $P_A$ if found out using the following equation and graph.
\begin{equation}
log_{10}P_{mm Hg}=6.61184-\frac{389.93}{266+T_{\degree C}}
\end{equation}
\begin{figure}[H]
\centering
\includegraphics[width=0.5\columnwidth]{methane_data.png}
% some figures do not need to be too wide
\caption{
\label{fig:methanedata}
Vapor pressure data for methane }
\end{figure}
\item The vapor pressure of methane at the temperature of -100 \degree C is found to me 18317.4 mm Hg.
\item Using equation 16, $P_B$ can be evaluated to be 8292.17 mm Hg.
\begin{equation}
\alpha=\frac{P_A}{P_B}=\frac{18317.4}{8289.17}=2.3
\end{equation}
\item With the reflux ratio fixed at 4, the following curve is being obtained by usage of the McCabe-Thiele Method.
\begin{figure}[H]
\centering
\includegraphics[width=1.1\columnwidth]{distillation.JPG}
% some figures do not need to be too wide
\caption{
\label{fig:distillation}
McCabe-Thiele solution for the de-methaniser unit. }
\end{figure}
\item The number of stages is found to be 20.8 and the feed tray is found to be the 11th tray.
\end{itemize}
\newpage
\subsection{Determination of column diameter}
The various pre-requisite parameters which have to be taken into consideration for the evaluation of the column diameter are presented in table 4.2
\begin{table}[H]
\caption{Various parameters and their values required for the calculation of column diameter } % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameters & Values \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Number of stages & 20\\
stage efficiency & 80\%\\
Real number of stages & 25 \\
Mol. wt of the feed & 22.875 \\
Slope of the bottom line (McCabe-thiele curve) & 1.5\\
Slope of the top line (McCabe-thiele curve) & 0.65\\
Feed flow rate (mton/day) & 804.948\\
Feed flow rate(kmol/day) & $35.19 X 10^3$\\
Top product rate (D)(mton/day) & 244.768\\
Top product rate (kmol/day) & $15.298 X 10^3$\\
Gas flow rate at the top, V= D(R+1) (kmol/day) &$76.49 X 10^3$ \\
Residue flow rate at the bottom (F-D) & $19.892 X 10^3$\\
Tray spacing (mm) & 600\\
\\% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation top} % is used to refer this table in the text
\end{tabular}
\end{table}
The important formulae used in the process of evaluating the column diameter are:
\begin{equation}
F_{LV}= \frac{L}{V} (\rho_V/\rho_L)^{0.5}
\end{equation}
\begin{equation}
u_f= K. \frac{\rho_L-\rho_V}{\rho_V}
\end{equation}
Assuming the actual velocity to be 85\% of the actual velocity to keep a check on flooding
\begin{equation}
u_v= 0.85u_f
\end{equation}
\begin{equation}
Max-volumetric-flow-rate, V_m= \frac{mass-flow-rate}{\rho}
\end{equation}
\begin{equation}
A= \frac{V_m}{u_v}
\end{equation}
\begin{equation}
diameter, d={(\frac{4A}{\pi})}^{0.5}
\end{equation}
The evaluated parameters of the top section of the distillation column have been shown in the table 4.3 below:
\begin{table}[H]
\caption{Parameters of the top half of the column} % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameters & Values \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$\rho_V (kg/m^3)$ & 0.656 \\
$\rho_L (kg/m^3)$ & 422.6\\
$F_{LV}$ & 0.026\\
$u_f (m/s)$ & 3.04\\
$u_v (m/s)$ & 2.6\\
$Vm (m^3/s)$ & 21.59\\
$A (m^2)$ & 8.3\\
$d (m) $ & 3.25\\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation bottom} % is used to refer this table in the text
\end{tabular}
\end{table}
The evaluated parameters of the bottom section of the distillation column have been shown in the table 4.4 below:
\begin{table}[H]
\caption{Parameters of the bottom half of the column} % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Parameters & Values \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
$\rho_V (kg/m^3)$ & 1.18 \\
$\rho_L (kg/m^3)$ & 570\\
$F_{LV}$ & 0.0682\\
$u_f (m/s)$ & 2.63\\
$u_v (m/s)$ & 2.24\\
$Vm (m^3/s)$ & 12.96\\
$A (m^2)$ & 4.9\\
$d (m) $ & 2.48 \\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation data} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{itemize}
\item The chosen diameter of distillation column in 3.25 m. To standardize the size, we take 12 ft size= 3.66 m.
\item The cross sectional area area of the distillation column is 10.52 $m^2$.
\item The downcomer area is 12\% of the total area, 12\% of 10.52 = 1.26 $m^2$
\end{itemize}
\newpage
\section{Design of the heat exchanger}
The transfer line heat exchanger is being designed. The assumptions used in the heat exchanger are as follows:
\begin{itemize}
\item Steady state heat flow
\item Convective Heat Transfer Coefficient is Constant throughout process
\item The tube side fluid is taken to be naphtha.
\item Data unavailable is assumed from reliable sources.
\end{itemize}
The design details of the transfer line heat exchanger are as follows:
\begin{itemize}
\item Fluid on shell side: naptha
\item Fluid on tube side: Product recovery
\item Heat capacity on tube side : Cp =1.8828 $kcal/kg/\degree C$
\item For Shell side:
Inlet temperature = 25 \degree C,
Outlet temperature = 180 \degree C
\item For Tube Side:
Inlet temperature = 700 \degree C
Outlet temperature = 581 \degree C
\item Shell side flow rate = 1660 metric ton/day
\item Tube Side flow rate = 2470 metric ton/day
\item Heat Load= 1064548.384*(700-581)=126681257.7 Kcal/day = 6134.656112 KW
\item U=550 $W/m^2$ \degree C
\item $\Delta T_{LMTD}$=36/.0669=537.8
\item Provisional Area= 6134656.112/550*537.8=21.567 $m_2$
\item Outside Diameter of tube = 25mm
\item Inside Diameter of tube = 19mm
\item Tube Length= 6m
\end{itemize}
\subsubsection{Tube side coefficient and $\Delta P_t$ }
Tube side Coefficient :
\begin{itemize}
\item Mean Temperature = 640.5 \degree C
\item Tube Cross sectional area =$\pi$/4*192=283.53 $mm^2$
\item Area of one Tube = $\pi$∗$d_o$∗L= 0.471 $m^2$
\item No. of tubes = $\frac{Provisional area}{Area of one tube}$= 21.567/.471 = 44.034=46.
\item Tubes per pass = 45 (No. of Passes is taken as 1)
\item Total flow area per pass = 46*283.53*$10^{-6}$ $m_2$ =12.98* $10^{-3}$$m^2$
\item Density=700 $kg/m^3$
\item Mass Velocity=3.134 m/s
\item $\mu$ =0.73 CP
\item Re=57098.8, k=.01
\item Pr=$uCp/k$=.00073*1880/.15=577.26
\item L/D=6000/19=315.79
\item $J_h$=.0025(from graph )
\item $J_f$= 0.0042 (from graph)
\begin{equation}
\frac{h_i*d}{k}=J_h*Re*pr^{0.33} (u/u_w)^{0.14}
\end{equation}
\item Using the above equation and putting the necessary values, we get, $h_i$=980 $W/m^2$ \degree C
\item Pressure Drop:
\begin{equation}
\Delta P=N_p[8J_f*(L/d)+2.5]*\rho*\frac{u_t^2}{2}=34648.28 N/m^2= 5 psi
\end{equation}
\item The tube side pressure drop is within the allowable pressure drop on tube side of 10 psi.
\end{itemize}
\subsubsection{Shell side coefficient and $\Delta P$}
\begin{itemize}
\item We used pull through floating head and therefore, the clearance for the calculated bundle diameter of 254.6 mm, is found to be 88 mm.
\item $D_s$ = Clearance *2+ = 88*2+ 254.6= 430.6 mm
\item Baffle spacing is taken t 25\% of the shell diameter $l_b$= $D_s/4$ =86.12 mm
\item Pitch = outer diameter* 1.25 = 31.25
\item Assuming Square Pitch for effective cleaning of the tubes, the effective diameter can be computed by the formula below:
\begin{equation}
d_e=\frac{1.27}{d_o}(P_t^2-0.785d_o^2)
\end{equation}
\item The effective diameter is evaluated to be 24.68 mm.
\item The cross flow area is computed by the following equation:
\begin{equation}
CFA=\frac{P_t-d_o}{P_t}*D_s*l_b=0.00741 m^2
\end{equation}
\item Velocity = 3.38 m/s
\item Reynold's Number is:
\begin{equation}
Re=\frac{\rho*v*d_e}{\mu}=88590.753
\end{equation}
\begin{equation}
Pr= \frac{\mu C_p}{k}=10.17
\end{equation}
\item $J_h$(from graph)= 2.2*$10^{-3}$
\item We are neglecting the correction in heat transfer coefficient due to variation in viscosity
\item The heat transfer coefficient on the shell side can be find using the equation below:
\item We take the baffle cut to be 25\%
\begin{equation}
\frac{h_s *d_e}{k_f}=J_h.Re.Pr^{1/3}(\mu/\mu_w)^{0.14}
\end{equation}
\item The $h_s$ is computed to be 2514.07 $ W/m^2/\degree C$
\item The tube side fouling factor on the tube side is 8000 $W/m^2/\degree C$ and on the shell side is 9000 $W/m^2/\degree C$.
\item Here the value of thermal conductivity of naphtha is, $k_f$, is taken to be 0.15 $W/m/\degree C$
\item Here the value of thermal conductivity of naphtha is, $k_w$, is taken to be 43 $W/m/\degree C$
\item The overall heat transfer coefficient of the shell and tube side is found out by the relation is as below:
\begin{equation}
\frac{1}{U_o}=\frac{1}{h_s}+\frac{1}{h_t}+\frac{d_o.ln(d_o/d_i)}{2k_w}+\frac{d_o}{d_i}\frac{1}{9000}+\frac{d_o}{d_i}\frac{1}{8000}
\end{equation}
\item The value of $U_o$ is calculated to be 480.076 $W/m^2$.
\item The pressure on the shell side can be found out to be:
\begin{equation}
\Delta P_s=8J_f\frac{D_s}{d_e}\frac{L}{l_b}\frac{\rho.u_s^2}{2}(\frac{\mu}{\mu_w})^{-0.14}
\end{equation}
\item The shell side pressure drop on substitution of the values is found to be 20899.368 $N/m^2$
\end{itemize}
\section{Design of Reactor}
The consideration for design of reactor design are as follows:
\begin{itemize}
\item The residence time of the reaction is taken to be 5 minutes, $\tau$ = 300 seconds.
\item $\rho$=1.027 $kg/m^3$
\item The volumetric flow rate, $v_o$ is
\begin{equation}
\frac{V}{v_o}=\tau
\end{equation}
\item From the above equation, the volume of the reactor is calculated to be, 39.65 $m^3$.
\item The ratio of $\frac{H}{D}$=4
\begin{equation}
\frac{\pi*d^2*H}{4}=\pi*d^3=39.65
\end{equation}
\item Solving the above equations, d= 2.328 m and H= 9.313 m.
\item Assuming clearance above and below the bed to be 1/8th of H, the total height = (2*1/8+1)H= 5/4*H=11.64 m.
\end{itemize}
\newpage
\mychapter{5}{CHAPTER 5\quad PLANT AND SITE LAYOUT}
The economic construction and efficient operation of a process unit will depend on how
well the plant and equipment specified on the process flow-sheet is laid out.
A detailed account of plant layout techniques cannot be given in this short section.
The principal factors to be considered are:
\begin{enumerate}
\item Economic considerations: construction and operating costs
\item The process requirements
\item Convenience of operation
\item Convenience of maintenance
\item Safety
\item Future expansion
\item Modular construction
\end{enumerate}
The main areas which are to be taken into consideration when coming up the plant layout are as follows:
\begin{itemize}
\item Plant area, which includes
\begin{enumerate}
\item Area for furnace, which needs to be in one column because of its highly hazardous nature.
\item Area for raw materials storage- naphtha and fuel. Storage area to be kept at sufficient distance from the furnace to avoid explosion in case of any mishap in the furnace
\item Area for distillation columns to be kept at the center as this is the main unit in the
\item Reactor area
\item Area to setup the caustic wash unit
\item A dedicated strip area to place the inter-stage compressors so as to keep them adjacent to the distillation columns.
\item Area for expansion in future
\item Area for utility generation, such as generation of steam and supply of other heat transfer utility
\end{enumerate}
\item Administrative area which constitute of the following area:
\begin{enumerate}
\item Administrative office
\item Training center
\item Parking Area
\end{enumerate}
\item Area for fire safety
\item Storage tank area.
\item Waste treatment plant
\item Control and maintenance area which has the following units
\begin{enumerate}
\item Warehouse
\item Maintenance
\item Workshop
\item Laboratory
\item Control building
\end{enumerate}
\end{itemize}
A plant layout taking into account the aforementioned units/areas has been designed in the attached appendix.
\newpage
\newpage
\mychapter{6}{CHAPTER 6\quad SAFETY ANALYSIS}
\section{Exposure Potential}
Ethylene exists naturally in the environment, where it is produced by vegetation and other natural sources. It is also a combustion product from vehicle exhaust, forest fires, and cigarette smoke.
\subsection{Workplace Exposure}– Exposure can occur either in facilities that recover or produce ethylene, during transport, or in facilities that use ethylene. Workplace exposure e to elevated levels of ethylene is limited due to concerns for flammability. Ethylene is produced, distributed, stored, and consumed in closed systems. Those working with ethylene in manufacturing operations could be expose d during maintenance, sampling, testing, or other procedures.
The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted a Threshold Limit Value (TLV) of 200 ppm for ethylene as an 8-hour time-weighted average (TWA). Workers should consult with the appropriate regulatory agencies for exposure guidelines. Each manufacturing facility should have a thorough training program for employees and appropriate work processes, ventilation, and safety equipment in place to limit exposure. See Health Information.
\subsection{Consumer exposure to products containing ethylene}
No consumer uses of ethylene are known, so consumer exposure to commercially produced ethylene is unlikely. However, it is used to make plastics and other materials used in consumer products. For ex ample, plastic milk jugs and plastic bags a re made from high-density polyethylene, a polymer made from ethylene. Ethylene is naturally present in the environment, and the highest environmental concentrations are found in urban areas.
\subsection{Environmental releases}
Ethylene emissions from industrial facilities are subject to governmental requirements. As a result of these regulations and production facility operating conditions, the typical ambient air levels of ethylene will be significantly less than 1 ppm. Ethylene has a high vapor pressure and if released will tend to volatilize from water and soil and accumulate in the atmosphere. In the presence of oxygen, ethylene biodegrades with an estimated half-life of 1.9 days. It degrades more quickly in sunlight. This material is considered slightly toxic to aquatic organisms on an acute basis.
\subsection{
Large release} Industrial spills or releases are infrequent and generally contained. If a large spill does occur, the area should be isolated until the released gas has dispersed. Respiratory protection may be necessary for clean up. The primary hazard from a large release of ethylene is fire. Eliminate all sources of ignition immediately. Use only explosion-proof equipment; ground and bond all containers and handling equipment. Prevent entry into soil, ditches, sewers, waterways and/or groundwater.
\subsection{In case of fire}
Deny any unnecessary entry into the area. Do not attempt to extinguish the fire. Stop flow of material if possible and allow the fire to burn out. Extinguish small fires with water spray or fog, carbon-dioxide or dry-chemical extinguishers, or foam. If possible, fight the fire from a protected area or safe location. Firefighters should wear positive-pressure, self-contained breathing apparatus (SCBA) and protective firefighting clothing. The public should be warned of any downwind vapor explosion hazards. Vapors may travel a long distance and ignition or vapor flash-back may occur. Immediately withdraw all personnel from the area in case of rising sounds from venting safety device or discolorations of the container. Follow emergency procedures carefully.
\subsection{Health information}
\subsubsection{Eye contact} Contact with liquefied ethylene can cause frostbite.
\subsubsection{Skin contact} Contact with liquefied ethylene can cause frostbite. No adverse effects are expected from absorption through the skin.
\subsubsection{Inhalation}Because ethylene is a gas at normal temperatures and pressures, inhalation is the primary route of exposure. Ethylene has a low level of toxicity. No risk to human health has been identified from occupational exposure or exposure of the general public to atmospheric levels of ethylene. However, excessive exposure by inhalation may cause headache, dizziness, anesthesia, drowsiness, unconsciousness, or other central nervous system effects. In confined or poorly ventilated areas, the gas can accumulate and result in unconsciousness due to displacement of oxygen. The American Conference of Governmental Industrial Hygienists (ACGIH) has established a Threshold Limit Value (TLV) for occupational exposure to ethylene of 200 parts per million (ppm) as a time-weighted average (TWA). The odor threshold for ethylene is reported to be from 270 to 600 ppm, so odor is not an adequate warning property to prevent excessive exposure to ethylene. Consult governmental regulations for exposure guidelines for the geographic region of interest.
\subsubsection{Ingestion}Ingestion is unlikely because ethylene is a gas at normal temperatures. Ingestion of liquefied gas can cause frostbite of the lips, mouth, and throat.
\subsection{Other health related information}
Screening and long-term studies in laboratory animals suggest that exposure to ethylene does not affect fetal development or reproduction and does not cause cancer. Both in vivo and in vitro mutagenicity studies were negative for genetic toxicity. However, metabolic studies in animals and humans have revealed that ethylene is metabolized to ethylene oxide, which is known to have carcinogenic and mutagenic effects.
\section{Environmental information}
If released, ethylene tends to accumulate in the atmopsphere because of its high vapor pressure. In the presence of oxygen in the atmosphere, ethylene biodegrades with an estimated half-life of 1.9 days. It degrades even more quickly in sunlight.
Ethylene is slightly toxic to aquatic organisms in the most sensitive species tested. The minute amounts of ethylene measured in water represent little, if any, environmental hazard to aquatic animals. Ethylene has a low bioconcentration potential. Because ethylene has low toxicity and low potential for exposure, it is not likely to have adverse effects on terrestrial wildlife.
Ethylene exists naturally in the environment and is produced by plants as part of their life cycle and the ripening process. Ethylene also acts as a plant hormone in regulation of plant growth and development. Ethylene effects on plants appear to be complex, depend upon environmental conditions and stage of growth, and vary by species and cultivar.
\section{Physical hazard information}
Ethylene is an extremely flammable gas or pressurized liquid and should be used only in well-ventilated areas. It should be kept away from heat and sources of ignition.
Ethylene is stable at recommended storage conditions of less than 52°C (126°F). Decomposition with rapid pressure build-up can occur at storage conditions above 180°C (356°F) and 1136 kPa (150 psig). Avoid contact with oxidizing materials (such as chlorine and oxygen), mineral acids, metals, and metal chlorides. Hazardous polymerization can also occur at high temperatures or in the presence of free-radical initiators or activated materials, such as activated carbon or molecular sieves.
\newpage
\section{Material Safety Data sheet}
A sample material safety data sheet published by the Linde Group has been attached herewith for the reference of the readers on the material safety aspects of Ethylene.
\begin{figure}[H]
\centering
\includegraphics[width=0.9\columnwidth]{msds1.jpg}
% some figures do not need to be too wide
\caption{
\label{fig: msds1}
Material Safety Data Sheet- Page 1 }
\end{figure}
\newpage
\begin{figure}[H]
\centering
\includegraphics[width=1.1\columnwidth]{msds1.jpg}
% some figures do not need to be too wide
\caption{
\label{fig: msds2}
Material Safety Data Sheet- Page 2 }
\end{figure}
\newpage
\mychapter{7}{CHAPTER 7 \quad PROJECT ECONOMICS}
\section{General considerations}
\begin{itemize}
\item Basis for calculation of cost: 1 year
\item Working capital- 15\% of Capital Investment
\item General expenses= 3\% of manufacturing cost.
\item Safety and maintenance cost = 7\% of manufacturing cost
\item Total capital= working capital+fixed capital.
\item The following items will be considered for calculating the initial investment:
\begin{enumerate}
\item Land cost
\item Cost of all equipment
\item Cost of consultant for plant design
\item Cost of construction of buildings
\item Cost of setting up utilities
\item Cost of ensuring electrical connections and power supply.
\end{enumerate}
\item The following items will be considered in the working capital category:
\begin{enumerate}
\item Salary of employees
\item Salary of casual laborers
\item Cash Reserve
\item Maintenance and repair
\item Product and in process inventory
\end{enumerate}
\end{itemize}
\newpage The total cost production is calculated to be the actual cost involved in the manufacturing process summed with the general expenses incurred.\\
The various types of manufacturing costs are as follows:
\begin{enumerate}
\item Raw Materials
\item Utilities
\item Labor and Supervision
\item Maintenance and repair
\item Operating Supplies
\item Taxes and Insurance
\item Plant Overhead
\item Depreciation
\end{enumerate}
The various types of general expenses to be added to the manufacturing cost are as follows:
\begin{enumerate}
\item Administrative Expenses
\item Distribution and Selling Cost
\item Interest on capital Investment
\end{enumerate}
The factors to be considered for the economic analysis:
\begin{enumerate}
\item Gross Annual Income
\item Annual Cost of Production
\item Gross Profit
\item Income Taxes
\item Net Profit
\end{enumerate}
\newpage
Th table below shows the delivered equipment cost of equipments that would be used in the plant:
\begin{table}[H]
\caption{Approximate installation and maintenance cost of the equipment being used} % title of Table
\centering % used for centering table
\begin{tabular}{c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Equipment & Installation cost(Rs) & Annual Operational cost (Rs) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Furnace & 234000000 & 0\\
Compressors (4) & 520000000 & 260000000\\
Distillation columns (5) & 1625000000 & 672750000\\
Refrigeration setup & 520000000 & 65000000\\
Quench section & 4550000 & 24050000\\
Total & 2424500000 & 1021800000\\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation bottom} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Approximate Cost of Raw materials } % title of Table
\centering % used for centering table
\begin{tabular}{c c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Product & Rate(Rs per kg) & Flow rate (kg/yr) &Total cost(\$) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Heavy Naphtha & 20 & 605900000 & 1211800000 \\
Steam & 0.5 & 295650000 & 14782500 \\
Natural Gas & 36 & 38690000 & 1,392,840,000\\
Total & & & 13525622500 \\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation bottom} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Approximate revenue generated from the major products} % title of Table
\centering % used for centering table
\begin{tabular}{c c c c} % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Product & Rate(Rs per kg) & Flow rate (kg/yr) &Total revenue (\$) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Ethylene & 71.55 & 182500000 & 13057875000\\
Methane & 35 & 89425000 & 3129875000\\
Total & & & 16187750000 \\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:distillation bottom} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Approximate cost of other utilities being used} % title of Table
\centering % used for centering table
\begin{tabular}{c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Item & Cost (Per Year) \\ [0.7ex] % inserts table
%heading
\hline % inserts single horizontal line
Process Piping & 7359794.00 \\
Electrical Equipment & 2886598.00 \\
Instrumentation &
5456577.00 \\
Building & 5679790.00 \\
Excavation and site preparation & 3859794.00\\
Auxiliaries &
10432950.00 \\
Total physical plant & 54021960.00 \\
Field Expenses & 8536392.00 \\
Engineering &
7636292.00 \\
Direct plant & 73370105.00 \\
Contractor, Overhead&
2256917.00 \\
Contingency &
7337732.00 \\
Total fixed investment & 90557734.6 \\
Every cost regarding pump & 9547392.00\\
Total & 288940028\\
Total (rounded off) & 289,000,000\\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:} % is used to refer this table in the text
\end{tabular}
\end{table}
\begin{table}[H]
\caption{Approximate cost of other utilities being used} % title of Table
\centering % used for centering table
\begin{tabular}{c c c c } % centered columns (4 columns)
\hline\hline %inserts double horizontal lines
Staff & No. & Salary per month (Rs.) & Total (Rs.) \\ [0.5ex] % inserts table
%heading
\hline % inserts single horizontal line
Plant Manager & 1 & 200000 & 200000 \\
Chief Engineer & 4 & 100000 & 400000\\
Assistant Engineer& 8 & 75000 & 600000 \\
Junior Engineer& 10 & 50000& 500000\\
Supervisor& 15 & 35000 & 525000\\
Operator & 20 & 25000 & 500000\\
Labor & 50 & 10000 &
500000\\
Chemist & 16 & 20000 &
320000\\
Office Staff & 29 & 25000 & 725000 \\
Security staff & 30 &
15000 & 450000 \\
Driver & 10 &
12000 & 120000\\
Total & & & 4840000\\
Annual Total & & & 58080000\\
% inserting body of the table
[1ex] % [1ex] adds vertical space
\hline %inserts single li
\label{table:} % is used to refer this table in the text
\end{tabular}
\end{table}
The inferences from the analysis of the cost of the project gives us the following highlights:
\begin{itemize}
\item The total annual cost for raw materials is: Rs.13,525,622,500
\item The total annual operation cost of equipments is: Rs. 1,021,800,000
\item The operational cost of utilities is: Rs. 289,000,000
\item The total annual amount spend in salary:Rs. 58,080,000
\item The total annual revenue obtained from the project is: rs. 16,187,750,000
\item The total annual gross profit generated: Rs. 1,345,519,500
\item The total annual net profit generated after deduction @ 30\% = Rs. 941,863,650
\item The total fixed capital at the beginning: Rs. 2,424,500,000
\item The pay back period is therefore: 2.57 years.
\end{itemize}
\mychapter{8}{Conclusion}
The project reflected the nuances of designing a plant. Even through the design is in the very nascent of its form and no where close in merit with respect to actual plant design, we would like to believe that it is, nonetheless, an appropriate representations of how plant designs should be carried out.\\
Some of the various short comings faced during the project are as follows:
\begin{itemize}
\item Availability of accurate data with respect to the variable used in the plants was very difficult to find.
\item A large number of close approximations have been used which makes the project less accurate.
\item The design procedure that we are acquainted with at our level of knowledge were not very sufficient to do justice to a complicated plant design.
\item Scarcity of availability of concrete data from the industry was also a major hurdle in the successful completion of the project
\end{itemize}
Some of the takeaways from the experience of the project can be summarized as follows:
\begin{itemize}
\item Every plant design project has to involve an extremely rigorous data collection in the first phase of the project
\item The plant design should be carried out manually as much as possible as it is, if not anything, a great learning experience for undergraduate students.
\item Sometimes it becomes difficult to get past a certain section because of the inherent difficulty of the section. However, in these situations other parts of the project work which have no relation to the part we are stuck in, should be attended to. Parallel flow of task will allow for optimization of time and give time for generation of ideas without stalling the process.
\end{itemize}
\begin{appendices}
\chapter{Graphs used for design of heat exchanger}
\begin{figure}[H]
\centering
\includegraphics[width=0.8\columnwidth]{hx1.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx1}
Finding out clearance using bundle diameter}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{hx2.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx2}
Table to find the bundle diameter using the number of passes}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{hx3.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx3}
Chart to find the heat transfer factor on the tube side}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{hx4.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx4}
Chart to find the heat transfer factor on the shell side}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{hx5.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx5}
Chart to find the friction factor on the shell side}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{hx6.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: hx6}
Chart to find the friction factor on the tube side}
\end{figure}
\newpage
\chapter{Graphs used for design of distillation column}
\begin{figure}[H]
\centering
\includegraphics[width=0.8\columnwidth]{dx1.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: dx1}
Chart to find value of K1 based on the tray spacing and value of FLV}
\end{figure}
\begin{figure}[H]
\centering
\includegraphics[width=0.5\columnwidth]{dx2.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: dx2}
Chart to find operation range of the distillation column}
\end{figure}
\chapter{Heat Exchanger: Detailed Engineering Drawing}
\begin{figure}[H]
\centering
\includegraphics[width=0.35\columnwidth]{heat_exchanger-1.jpg}
% some figures do not need to be too wide
\caption{
\label{fig: hx-1}
Designed heat exchanger(all units in metres}
\end{figure}
\newpage
\chapter{Furnace: Detailed Engineering Drawing}
\begin{figure}[H]
\centering
\includegraphics[width=1.2\columnwidth]{furnace-1.jpg}
% some figures do not need to be too wide
\caption{
\label{fig: furnace-1}
Designed Furnace (all units in metres) }
\end{figure}
\newpage
\chapter{Distillation Column: Detailed Engineering Drawing}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{distillation-1.jpg}
% some figures do not need to be too wide
\caption{
\label{fig: distillation-11}
Designed distillation column}
\end{figure}
\newpage
\chapter{Plant Layout Diagram}
\begin{figure}[H]
\centering
\includegraphics[width=1\columnwidth]{plant.JPG}
% some figures do not need to be too wide
\caption{
\label{fig: plant}
Plant Layout Design}
\end{figure}
\end{appendices}
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\end{document}