Study On Fushun Shale Oil Catalytic Cracking For Maximizing Propylene Yield By TMP Technology

Propylene is one of the most important raw materials for organic chemical industry, which is mainly derived from naphtha steam cracking process and heavy oil catalytic cracking. The steam cracking process exists some defects, such as high energy consumption, low propylene yield, lack of light feedstock, which make producing propylene process by FCC (Fluid catalytic cracking) develops rapidly. Research and exploitation on unconventional energy play a tremendous role along with the growth of contradiction between conventional energys'supply and demand, unconventional energys become important supply energy of petroleum. Study on shale oil catalytic cracking for maximizing propylene was made by TMP Technology.FuShun Shale oil is regarded as a good potential FCC feed for producing light olefins because of its high saturates content and high percentage of hydrogen, but it should be noticed that the nitrogen content and basic nitrogen compounds can reach 1.27% and 0.629%, respectively. The results shows that the final propylene yield approaches 17.27% by conventional TSRFCC technology, but the coke yield can reach 16.49%.Considering shale oil's poor quality and high coke yield, then, it is hydrotreated by Fu Shun Mining Bureau. The analyze data shows that the quality of raw material properties is improved after being hydrotreated, obviously, it has lower nitrogen content, in addition, the saturate and the hydrogen content are increased obviously, which can reach 88.36% and 13.70%, respectively. The results shows that the hydrotreated shale oil is easier to crack under conventional FCC conditions, we should control operating conditions avoid over-cracking and unnecessary secondary reactions.This paper chooses hydrotreated shale oil mixed with 30% residual oil as raw material to produce more propylene by TMP technology, using the method of stratifying injection of C₄ and light FCC naphtha distillation, respectively, which contains high olefin-degree light feedstock. The result shows that the whole product distribution can be acceptable completely under less serious conditions (reaction temperature T:480℃,the ratio of catalyst to oil C/O:6.9/12,reaction time S:1.27s/0.77s). The final propylene yield can reach 21.40%, meanwhile, we can obtain high light oil yield and guarantee the quality of light oil.Besides, we also investigate catalytic cracking reaction under pressured conditions so as to simulate industrial conditions. The result shows that the final product distribution is similar when we mixed different residual oil in hydrotreated shale oil, the whole final propylene yield can approach 20%, and it is proved that choosing hydrotreated shale oil as FCC feedstock to produce propylene is economic and feasible.