The process to be modelled is part of the production of methanol from

Natural Gas.

It is assumed that the Natural Gas is already converted to Synthesis Gas

$($Syngas$)$ with the following composition and conditions:

Temperature $131\mathrm{.}7$C

Pressure $1187$ psiaPressure $1187$ psia

Component and Composition $($mol$\%)$

Carbon Monoxide $(15\mathrm{.}63)$

Carbon Dioxide $(7\mathrm{.}93)$

Hydrogen $(73\mathrm{.}31)$

Nitrogen $(0\mathrm{.}33)$

Methane $(2\mathrm{.}61)$

Water $(0\mathrm{.}19)$

TOTAL $100\mathrm{.}00$ The flow of the Syngas stream is $950$ kgmole$/$hr$.$ The feed stream is mixed with the recycle and heated to a temperature of

$130$C$,$ and the pressure drop across this exchanger is assumed to be

zero. This stream is fed to the reactor which performs the following two

equilibrium reactions:

CO$2+$ H CH$3$OH $+$ H$2$O

CO $+$ H CH$3$OH

Note that both of these reactions are reversible, and the overall reaction is

exothermic. Note that there is a pressure drop of $186$ kPa across this reactor.

The reactor effluent is cooled to a temperature of $37\mathrm{.}78$C in a cooler which

has a pressure drop of $110\mathrm{.}3$ kPa. This stream is then flashed to give

vapour and liquid streams.

The pressure drop across this flash separator is assumed to be zero. The

vapour stream is sent to the recycle, but before this a purge stream is taken

off. This purge stream is set at $4\mathrm{.}8\%$ of the vapour stream from the flash.

After this purge stream is taken off, the recycle stream is compressed to

$8190$ kPa before being returned to mix with the feed.

The recycle compressor has an adiabatic efficiency of $70\%.$

The liquid stream from the first flash is sent to a second flash separator at

the lower pressure of $301\mathrm{.}4$ kPa to produce a liquid crude methanol product

and a vapour stream which is sent as $$loop flash gas$$ to the fuel system. QUESTION: $1.$hand calculate the percentage of methanol product. $2.$ Based on the number and type of process units required for this

process, evaluate safety and environmental concerns that can be

present and indicate some measurements or required controls.

Discuss if the operational units of methanol production are all

justified or recommend any additional operational unit.The following are appropriate economic values:

$\backslash$table$[[$Item$,$Unit Cost$/$Value of item$],[$Syngas Feed,$275\frac{\text{\$}}{t}e$