Methanol is a valuable product, because it is used as a feedstock for many chemical processes. A common way to produce high$-$purity methanol is through steam reforming of natural gas $($NG$).$ The natural gas is converted into synthesis gas, which then reacts to methanol in a subsequent section.

Design a process that produce $89\mathrm{.}28$ million kilograms of methanol per year and operates $8000$ h per year.

NG is $$rst sent to a Desulfurizer $(600$ K$)$ to remove any sulfur present in the natural gas, because the sulfur would poison catalysts in downstream processes. NG has the following composition $($CH$487$ vol$\%$; C$2$H$65$ vol$\%,$ CO$23$ vol$\%,$ N$25$ vol$\%,$ total S $<21000$ ppmV$)$

Steam is added to the desulfurized natural gas, and the combined gas is sent to a Reformer $($inlet temperature $600$ K$,$ outlet temperature $1300$ K$)$ to produce syngas $($gas mainly consist of CO and H$2).$ Assume $100\%$ conversions of CH$4$ and C$2$H$6.$ The yields of CO and CO$2$ are $95\%$ and $5\%,$ respectively. Steam is fed with $10\%$ excess.

Which possible reactions exist?

How much H$2$O is needed?

Material and mass balance.

How much heat is needed?

How much extra NG is needed to provide the heat for the reformer via combustion with Air $(30\%$ excess Air$)$

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The product gas from the reformer is cooled via a heat exchanger to $600$ K and then sent to the methanol reactor that operates at $600$ K$.$ Assume $96\mathrm{.}875\%$ conversion of CO and CO$2.$ The heat exchanger is used to evaporate and heat the water needed for the steam reforming.

Which possible reactions exist?

Material and mass balance.

Do we have enough H$2?$

How much heat is released?

Do you have enough heat to evaporated and superheat the water to $600$ K$?$ If not, do you another source of heat that could be used.

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The methanol rich gas is then sent through distillation column $(300$ K$)$ to separate methanol from unreacted H$2$ and CO$.$