Catalytic cracking catalyst capable of improving coke selectivity and preparation method of catalytic cracking catalyst

Abstract

The invention provides a catalytic cracking catalyst capable of improving the coke selectivity and a preparation method of the catalytic cracking catalyst. The catalyst is prepared from 15 to 70 weight percent of a molecular sieve, 15 to 60 weight percent of clay, 8 to 30 weight percent of pseudo-boehmite, 3 to 20 weight percent of a binding agent, 0.01 to 10 weight percent of phosphorus (based onP) and 0.01 to 5 weight percent of magnesium (based on Mg). The preparation method of the catalytic cracking catalyst comprises the following steps: mixing the molecular sieve, a pore-expanding agent, the clay, the pseudo-boehmite, a phosphorus-containing compound and the binding agent and pulping; spraying and molding; roasting a molded catalyst microsphere, and mixing with magnesium-containingcompound, ammonium salt and water and pulping; adjusting the pH (Potential of Hydrogen) value and raising the temperature and stirring; filtering and drying to obtain the catalytic cracking catalyst.Under the condition that the conversion ratio is improved and the content of heavy oil is reduced, the catalyst prepared by the method has more excellent coke selectivity.

Description

technical field [0001] The invention relates to a catalytic cracking catalyst and a preparation method thereof, in particular to a catalytic cracking catalyst for improving coke selectivity and a preparation method thereof. Background technique [0002] Fluid catalytic cracking technology (FCC) has become an important means of secondary processing of heavy oil due to its relatively low investment, strong feedstock adaptability, and simple operation. With the depletion of high-quality and light crude oil resources worldwide and the improvement of coking production capacity, oil refining companies have blended a large proportion of low-quality crude oil in catalytic cracking units, such as residual oil, coking wax oil, degassing oil, etc. asphalt oil etc. Due to the poor crackability of inferior feedstock oil, the amount of carbon deposited on the FCC catalyst increases, and the coke is adsorbed on the acidic center of the catalyst and is not easy to desorb, which seriously a...

AI Technical Summary

Problems solved by technology

[0015] It can be seen from the above patents that increasing the ratio of medium and large pores of the matrix material and increasing the diffusion rate of oil and gas molecules can improve the heavy oil conversion capacity and coke selectivity of the catalyst, but the improvement range is limited; and the modification of molecular sieves is the introduction of a single phosphorus element or a single magnesium element for modification

When the molecular sieve is modified with a phosphorus-containing solution, the phosphate is hydrolyzed to generate phosphoric acid, and due to the size and spatial configuration of the phosphoric acid molecule, the phosphoric acid cannot enter the pores of the molecular sieve and react with the strong acid centers in the channels [Shen Zhihong, Pan Huifang, Xu Chunsheng etc. Effect of phosphorus on surface acidity and carbon resistance of hydrocarbon catalytic cracking catalysts, Journal of Petroleum University (Natural Science Edition), 1994, 18(2): 86-99], so it cannot improve the coke selectivity of the acid center in the channel ; Magnesium ions have a small radius and can migrate into the pores of molecular sieves

However, due to the diffusion resistance of the pores, the magnesium ions will inevitably cover the outer surface of the molecular sieve and the acid centers in the large pores during the migration of magnesium ions to the pores, resulting in a decrease in the acid content of the molecular sieve and the loss of heavy oil conversion capacity.

Therefore, the above-mentioned patents cannot solve the contradiction between small-pore coke selectivity and heavy oil conversion at the same time

Images