A method for converting ethylene in catalytic cracking dry gas into propylene.
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It is a method for the comprehensive utilization of catalytic cracking dry gas. Using catalytic cracking dry gas as raw material, and within a fixed-bed fluidized reactor system with appropriate operating conditions and molecular sieve catalysts, the ethylene present in the catalytic cracking dry gas is oligomerized to selectively produce low-carbon hydrocarbons such as propylene or liquefied gas. The resulting products have high added value and are easy to recover, thus providing an effective approach for the comprehensive utilization of ethylene in catalytic cracking dry gas. Is there industrialization? Do everyone understand?
The Chemical Resources Laboratory at the Tokyo Institute of Technology in Japan has verified a catalytic reaction process for directly converting ethylene into propylene and butylene. This process exhibits high selectivity at atmospheric pressure, uses a nickel-based catalyst, and employs MCM-41 nano-porous silica as a carrier; MCM-41 features a regular 21-nanometer-scale porous structure. Ethylene and trace water react in a fixed-bed reactor using a nickel catalyst supported on mesoporous silica, with the net reaction producing two moles of propylene from three moles of ethylene. The actual reaction mechanism involves two reaction steps on the same catalyst: two molecules of ethylene first combine to form butylene, and then butylene undergoes transposition with a third molecule of ethylene to yield two molecules of propylene. In the one-way conversion, the ethylene conversion rate is approximately 53%, while the selectivities for propylene and butylene are about 50% and 42%, respectively. Butene further increases the propylene yield by reacting with ethylene, being converted into propylene using the same catalyst. This is the first time in the world that 3 ethylene molecules have been converted into 2 propylene molecules through a catalytic reaction. Using this process, at atmospheric pressure and 400°C, the ethylene conversion rate is 68%, the propylene selectivity is 49%, and the butene selectivity is 42%. If necessary, this technique can be used to better balance the olefin yield of the cracking unit. Combining the new process with existing ethylene-producing cracking units can increase propylene production, which is particularly useful when the demand for propylene exceeds that for ethylene. The laboratory has joined forces with industrial companies to advance this process toward industrialization.
Thank you. Is it not yet industrialized?