Problem of increased methanol production due to hydrogenation of off-gases?
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Our company is currently building a facility that uses coke oven gas as raw material to produce 100,000 tons of methanol per year; the design was carried out by Tianyi. In the original design, the off-gases were sent to a combined heating furnace for combustion. I have an idea: to build an intermittent gas generation furnace equipped with carbon, and to use these gases along with the off-gases in the methanol production process, thereby increasing the output of methanol. For the heat source of the integrated heating furnace, it can also be ensured by installing a new boiler. Is this feasible?
It is not necessary. The off-gas from synthesis, after hydrogen extraction, has a CO+H2 content of 45%-50%, while the CO2+CH4+N2 content is around 50%. For methanol synthesis, both methane and nitrogen are inert gases that do not participate in the reaction; they accumulate within the system. The purpose of using this synthesis off-gas is to regulate the level of inert gases. It is not feasible to send these inert gases back into the synthesis system.
Using membrane separation to extract hydrogen from the off-gas is a good option
The hollow fiber membrane separation device and its process technology developed by the Dalian Institute of Chemical Physics enable the recovery of hydrogen, thus meeting the requirements of the original poster.
The inert gas content in the vent gas is too high; even by adding hydrogen, it is not possible to remove these inert gases. If this gas is reintroduced into the synthesis section, the inert gas concentration will continue to rise, affecting the efficiency of the reactions.
Hydrogen can be extracted through membrane separation and used as fuel in the delivery area
May I ask the original poster: Has the gas you mentioned for release undergone membrane separation to extract hydrogen? Or directly from the synthesized purge gas? The specific situation depends on the composition of the gases in your off-gases. It’s a good idea to consider installing another batch-type gas generation furnace, but it’s necessary to take into account the specific process conditions. If the hydrogen content in your off-gases is high, then it’s certainly possible to add carbon to increase methanol production; however, if the hydrogen content is low, it might not be worthwhile. We are also producing methanol from coke oven gas, and we are currently in the design phase, with a capacity of 150,000 tons per year. The design was carried out by the Second Chemical Engineering Institute. Our off-gases are reused in boilers to replace part of the coke oven gas. If there’s a chance, let’s exchange ideas and learn from each other.
The design of a company should ensure that all its components are integrated and coordinated with each other; by sending the exhaust gas from the back section to the front section, the overall processing capacity of the equipment is increased. But too much exhaust gas was released; it’s still heartbreaking!
There’s no need. Just extract hydrogen; adding more equipment is a waste. The exhaust gas volume is unstable.
It’s okay to add hydrogen after stripping the vent gas; but if the vent gas is added directly, how can production proceed if the inert gas cannot be removed?
Methanol off-gas probably doesn’t have much utility! It is estimated that it will be very difficult to recoup the costs of the additional investment! Think it over carefully!
I suggest that it is more reasonable to use the released gas as furnace gas or fuel gas. For a system producing 100,000 tons of methanol from coke oven gas, one gas generation furnace can be installed for carbon supplementation.