MIP-CGP catalytic cracking process

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The heavy feed oil in the MIP-CGP process first contacts the high-temperature catalyst at the bottom of the first reaction zone to undergo a cracking reaction, aiming to crack the heavy oil and produce more light oil and olefins.； After the reaction oil, gas and steam mixture containing high olefins enters the second reaction zone, it contacts the coked catalyst at a lower reaction temperature for a longer period of time, and selectively carries out cracking reactions, isomerization reactions, aromatization reactions and hydrogen transfer reactions to crack as many linear olefins and alkanes in the gasoline component into small molecular olefins of C4 and below. At the same time, the olefins in the gasoline are also subjected to isomerization, hydrogen transfer and aromatization reactions, thereby achieving the purpose of improving the quality of the oil. From the perspective of the reaction process, the MIP-CGP process is a partitioned reaction, and the focus of the reactions carried out in each reaction zone is different. Therefore, when designing the CGP-1 catalyst, it is necessary to take into account the characteristics of each reaction zone to highlight its advantageous effects. To do this, the catalyst should have the following four main characteristics:: 1).Strong heavy oil cracking reaction capacity ； 2).Moderate hydrogen transfer activity ； 3). Good carbon holding performance; 4). High hydrothermal stability. The relationship between the composition and unique characteristics of the CGP-1 catalyst, the two reaction zones of the MIP-CGP process, and the target products can be seen in Figure 1. Active component 1. Strong heavy oil cracking capacity. First reaction zone increases liquid recovery. Good carbon holding capacity. Propylene has high hydrothermal stability. Active component 2. Moderate hydrogen transfer activity. Second reaction zone improves gasoline quality. Figure 1. Relationship between the composition and characteristics of CGP-1 and the two reaction zones and target products. The reaction severity in the first reaction zone is higher than that of the conventional FCC reaction system.: High temperature, short contact time and high agent-oil ratio focus on the cracking reaction of macromolecular hydrocarbons, and its main purpose is to produce more light oil and propylene, as shown in Figure 1. Therefore, the CGP-1 catalyst should have strong heavy oil cracking ability: Using active oxides to modify the existing active component 1 to increase its total acid content, especially increasing the strong acid content, can increase the probability of cracking reactions. After the high olefin content gasoline generated in the first reaction zone enters the second reaction zone, it is contacted with the partially coked catalyst at a lower reaction temperature for a longer period of time, focusing on the recracking, isomerization and hydrogen transfer reactions of the olefin components. Therefore, the CGP-1 catalyst is required to have moderate hydrogen transfer activity and good carbon holding performance, so that the catalyst is still in a good active state after passing through the first reaction zone. It can be seen from the principle of catalytic cracking reaction that the hydrogen transfer reaction is an important secondary reaction in the catalytic cracking reaction system and one of the characteristic reactions of catalytic cracking. Through reasonable distribution of hydrogen, the goals of producing more propylene, reducing the olefin content of gasoline, and increasing the content of isoparaffins and aromatics can be achieved without producing too much coke. It should be noted that an appropriate amount of active component 2 independently developed by RIPP is added to the CGP-1 catalyst, which can more effectively control the direction and depth of the secondary reaction. Due to its unique pore structure, it is almost not contaminated after the reaction in the first reaction zone, and the acid center is not covered. In this way, its role is still fully and effectively exerted at the lower reaction temperature of the second reaction zone. generally believed: In addition to the primary cracking reaction, more low-carbon olefins (such as propylene) come from the secondary cracking of gasoline fractions (especially C7~C9). The main contribution of active component 1 is to generate hydrocarbons above C5, while active component 2 cracks C7~C9 linear hydrocarbons into small molecular olefins of C4 and below.