Technology for Higher Propylene Yield      

The commercialization pilot test on the technology for the higher propylene yield through catalytic cracking developed by China Petroleum University has made great progress.
   Propylene is an important basic organic chemical raw material. It is mainly produced from naphtha steam cracking and catalytic cracking. Technologies for the higher propylene output through the catalytic cracking or pyrolysis of heavy oil have aroused widespread attention. The propylene yield through conventional catalytic cracking is however only 3%-5%. In stringent operating conditions, the propylene yield is increased but the dry gas yield will be much higher, and the yield and the quality of diesel will be negatively affected.
   The new technology has already been applied in the 120 000 t/a commercial pilot unit of CNPC Daqing Refining & Chemical Co., Ltd. Atmospheric residue from Daqing Refining & Chemical Co., Ltd. is used as raw material. The propylene yield already reaches more than 18% without reprocessing of blending C4. The total yield of LPG, gasoline and diesel is also close to 83%. The octane number of gasoline is close to 97, and the tail gas emission indexes of gasoline approaches the European III standard.
   According to experts, this major progress will promote the development of refining-chemical integrated technologies and produce a great positive impact on the propylene production in China.