Methanol coking?
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This post was last edited by liaifeng on 2018-9-1 at 11:58. In the methanol-to-olefins process, high reactor temperatures and a long contact time between methanol vapor and the catalyst can both lead to methanol coking. So what is the root cause of methanol coking? What is the specific manifestation?
Due to the significant heat release, the temperature of the reactor rises sharply, which exacerbates methanol coking and may lead to its decomposition; therefore, it is essential to remove heat promptly and make comprehensive use of the reaction heat.
What is the specific reaction mechanism?
Are you referring to the high-temperature carbonization of methanol? Combustible carbon-containing substances decompose into gases, liquids, and solids when heated in the absence of air. For example, coal is thermally decomposed into gas, tar, coke, etc. Carbonization is divided into high, medium, and low-temperature carbonization. What you said, that \"a long contact time between methanol vapor and the catalyst can lead to methanol coking,\" isn’t accurate, right? Since it is a catalyst, why doesn’t it react but instead undergoes carbonization?
It’s not carbonization of the catalyst; it’s the result of methanol vapor being in contact with the catalyst for too long, causing methanol to coking
Whenever I came into contact with the medium used in production, a reaction occurred. At the same time, they are basically lift pipes or fluidized beds, with very short contact times; the reaction time is on the order of milliseconds. It’s unclear why no reaction occurs, leading to carbon buildup on the catalyst. Could it be that the catalyst has become inactive?
At higher reaction temperatures, the catalyst’s activity increases, and the coking tendency of methanol rises; prolonged contact time causes the catalyst’s pores to gradually shrink, leading to coking. The manifestation is an increase in the levels of methanol and dimethyl ether in the product gas; over time the catalyst becomes inactive, methanol fails to react, and the reactor temperature drops.