What are the main operating factors that affect the conversion rate of the catalytic cracking unit reaction:

1. The nature of the raw oil

The properties of raw oil are mainly its chemical composition. The feedstock with more naphthenic content in the composition of the feedstock oil has faster cracking reaction speed, higher gas and gasoline yields, lower coke yields and better selectivity. For raw materials rich in aromatic hydrocarbons, the cracking reaction proceeds slowly and the selectivity is poor. In addition, the high residual carbon value and heavy metal content of the raw oil will increase the coke and gas yield.

2. Reaction pressure

The essence of increasing the reaction pressure is to increase the concentration of oil and gas reactants, or to be more precise, the increase of the partial pressure of oil and gas is conducive to the acceleration of the reaction speed. Increasing the reaction pressure is beneficial to the condensation reaction, the coke yield is significantly increased, the relative yield of olefins in the gas is decreased, and the gasoline yield is slightly decreased, but the stability is improved. The pressure of the riser catalytic cracking reactor is controlled at 0.3 MPa to 0.37 MPa.

3. Reaction temperature

The reaction temperature has a great influence on the reaction rate, product distribution and product quality. In production, temperature is the main factor to adjust the reaction rate and conversion rate. For different product schemes, choose different reaction temperatures to achieve. For the multi-product diesel scheme, use a lower reaction temperature and operate at a low conversion rate and a high recovery ratio. . For the prolific gasoline scheme, the reaction temperature is higher; a high conversion rate and a low recycle ratio are used.

4. Airspeed and reaction time

The reaction time in the riser reactor is the residence time of the oil and gas in the riser.