UOP and Atofina have made the jointly developed olefin cracking process (OCP) industrialized. The OCP process can convert C4 to C8 olefins to propylene and ethylene. The process can utilize steam cracking units, catalytic cracking units, and methanol. C4 to C8 olefin streams converted to olefin plants. The OCP process uses a fixed bed reactor with operating conditions of 500-600°C and 0.1-0.5 MPa. The C4 to C8 olefins are cleaved by means of a dedicated zeolite molecular sieve catalyst, using this catalyst with a high propylene yield. The catalyst was regenerated using a switched reactor system. The combination of OCP and naphtha cracker shows that, for a relative naphtha flow rate, the propylene yield can be increased by 3%. As a result, the net propylene/ethylene ratio is 0.8, and the combined investment increase is estimated at 72 million. In US dollars, the repayment period is 4 years. The verification device has been put into operation at Atofina's plant in Antwerp, Belgium, and further optimization of the OCP process is under way.
The Institute of Resource Chemistry, Tokyo Institute of Technology, Japan developed a novel catalytic reaction process for the direct synthesis of propylene from ethylene. The new process utilizes nickel ions of a silicon nanoporous body as a catalyst. The solid catalyst reaction process enables the continuous conversion of raw material ethylene to propylene and Butene. Several petrochemical companies are already involved in this technology development.
The Chemical Resources Laboratory of Tokyo Institute of Technology in Japan verified the catalytic reaction process for the direct conversion of ethylene to propylene and butene. The process has a high selectivity at atmospheric pressure, using a nickel-based catalyst to MCM-41 nanoporous 2 Silicon oxide is the carrier and MCM-41 is a regular 21 nanometer porous structure. Ethylene and trace amounts of water are reacted in a fixed bed reactor with a nickel catalyst supported on mesoporous silica. The net reaction produces two moles of propylene from three moles of ethylene. The actual reaction mechanism is to complete two reaction steps on the same catalyst: two molecules of ethylene are first combined to produce butene, and then butene and third ethylene are metathesized to form two propylene molecules. In a single pass conversion, the conversion of ethylene is about 53%, and the selectivities of propylene and butenes are about 50% and 42%, respectively. Butenes further increase the propylene yield by reacting with ethylene and are converted to propylene by the same catalyst. This is the first reaction in the world to convert three ethylene molecules into two propylene molecules through a catalytic reaction. With this process, the ethylene conversion was 68% at normal pressure and 400°C, the propylene selectivity was 49%, and the butene selectivity was 42%. If desired, this technique can be used to better balance the olefin yield of the cracker. The combination of the new process with the existing ethylene production cracker can increase propylene production, which is particularly useful when the propylene demand is greater than the ethylene demand. The laboratory has joined forces with industrial companies to make the process industrialized.