Method and Device for Catalytic Cracking

A catalytic cracking method, wherein a catalytic cracking reaction is performed in a reaction-regeneration device which comprises a reaction part provided with a riser reactor and a regeneration part including a regenerator,

• wherein the reaction part is comprised of the riser reactor, a stripping area for the catalyst to be regenerated and a settler;
• the riser reactor comprises a pre-rising section, a raw oil reaction area, a catalyst-separating area, a supplementary catalyst distribution area and an oil-gas repeat reaction area from bottom to top;
• the catalyst-separating area is arranged at an outlet of the raw oil reaction area;
• a passage is provided between the catalyst-separating area and the oil-gas repeat reaction area, and the periphery of the passage is the supplementary catalyst distribution area;
• wherein the regenerator is provided with a first regeneration area, a dense-phase fluidized bed area and a dilute-phase catalyst settlement separation area from bottom to top;
• wherein the regenerated catalyst from the dense-phase fluidized bed area enters the pre-rising section and the supplementary catalyst distribution area of the riser reactor in the manner as follows, respectively:
• entering the pre-rising section:
• the regenerated catalyst directly entering the pre-rising section, or entering the pre-rising section by gravity after cooling, or the regenerated catalyst and the regenerated catalyst after cooling simultaneously entering the pre-rising section via two separate passways;
• entering the supplementary catalyst distribution area:
• the regenerated catalyst entering the supplementary catalyst distribution area by gravity after cooling;
• the catalytic cracking reaction method comprising:
• mixing the regenerated catalyst in the pre-rising section with a preheated reaction raw oil material after the regenerated catalyst has entered the pre-rising section;
• carrying out the catalytic cracking reaction in the raw oil reaction area after the mixture of the regenerated catalyst and the preheated reaction raw oil flows upwards along the riser reactor into the raw oil reaction area;
• generating the oil-gas and the catalyst during the catalytic cracking reaction, wherein the catalyst and the oil-gas generated by the catalytic cracking reaction flow upwards into the catalyst-separating area;
• tangentially separating part of the catalyst by means of gas-solid outward vortex, wherein the part of the catalyst that has been separated flows downwards due to gravity into the stripping area for the catalyst to be regenerated;
• maintaining part of the catalyst in the oil-gas, wherein the oil-gas and the catalyst that has not been separated continue to flow upwards;
• mixing the oil-gas, the catalyst that has not been separated, and the regenerated catalyst which has entered the supplementary catalyst distribution area before the mixed oil-gas, the catalyst that has not been separated, and the regenerated catalyst which has entered the supplementary catalyst distribution area enter the oil-gas repeat reaction area;
• carrying out an oil-gas catalytic repeat reaction in the oil-gas repeat reaction area;
• and
• separating the oil-gas and the catalyst within the riser reactor in the settler via a gas-solid separation after the catalytic repeat reaction ends, wherein the oil-gas enters a fractionating system via an oil-gas pipeline, and wherein the catalyst to be regenerated in the raw oil reaction area and the oil-gas repeat reaction area enters the regenerator for activity recovery after being subjected to steam stripping in the stripping area for the catalyst to be regenerated.