At this stage, researchers mainly improve the performance of catalytic cracking tower bottom oil cracking additives by improving their acid properties and pore structure. In response to the characteristics of seasonal demand for diesel and high gasoline inventory.
The Research Institute of Petrochemical Sciences has developed a tower bottom oil cracking additive LDC-971, which can significantly increase the proportion of diesel output; in order to adapt to the characteristics of diversification and inferiority of residue catalytic cracking crude oil, the Nanjing Refinery of Jinling Petrochemical Company has developed a tower bottom oil cracking additive consisting of four components, Al, Si, Mg and P, with obvious effect.
3.3 Vanadium fixing agent in catalytic cracking
The metal element vanadium has a certain toxicity in the petroleum refining process, which affects the product quality and catalyst activity. Vanadium in the reduced state can react with crude oil to produce large amounts of coke and hydrogen, and affect the selectivity of the final product; vanadium acid generated from vanadium in the oxidized state can react with aluminum and rare earth elements in zeolites, making changes in the crystal structure of zeolites and affecting catalytic activity.
The early catalytic cracking process had a weak vanadium absorption capacity of 2-3 times the vanadium content of the catalyst; the vanadium absorbing capacity of the solids developed since the 1980s has nearly doubled. The latest vanadium fixing agent active components are mainly alkali metals, rare earth metals and elements such as titanium, zirconium, tin and chromium.
4 Oil quality improvement additives
4.1 catalytic cracking gasoline octane additives
In order to adjust the octane value of gasoline, researchers have developed a large number of octane additives in recent years, such as octane additives prepared by phosphorus aluminum silicon (SAPO) zeolite, Nu-86 and Nu-87 octane additives, ZSM-5 and ga/ZSM-5 combination octane additives.
On the basis of ZSM-5 molecular sieve, Petrochemical Scientific Research Institute developed MFI type ZRP series molecular sieve with high silica-aluminum ratio and high stability, which overcomes some shortcomings of ZSM-5 molecular sieve; LCS-7C catalyst produced by Lanzhou Petrochemical Company is compounded with ZRP-5 selective molecular sieve on REHY molecular sieve; Dalian Petrochemical Company applied LCS-7C catalyst to process paraffin-based feedstock to improve ROM+MON by 2 units, and the ROM and MON of gasoline were 89.7 and 79.4, respectively, and the diesel yield reached 31%, and the total liquid yield was unchanged.
4.2 Regulation of catalytic cracked gasoline olefin ratio additives
The granitic pegmatite veins in the district were mainly formed in the Silurian and formed several dense zones of granitic pegmatite veins of varying sizes. The granite pegmatite veins are spatially controlled by the Silurian gray pools of ineritic amphibolite - granite amphibolite - diorite granite body.
The granite pegmatite veins are located in the inner and outer contact zone of the Middle Metasedimentary Xiahe Group, Middle Metasedimentary Qinling Group and Ash Pond sub-body. Its morphology is mostly vein-like (about 84%), and the rest are branched, lenticular, cystic, and expanded and contracted. The veins are mostly moderately inclined to gently inclined, and those with steeper dips are generally larger.
