Catalytic cracking process for reducing sulfur content in gasoline and the device thereof

摘要

The invention relates to a catalytic cracking process for reducing sulfur content in gasoline and the device thereof, which includes a fluidized bed reactor in addition of a heavy oil catalytic cracking riser, characterized in enhancing contact time of oil-gas with the catalyst, further desulfurizing and reducing olefin content and increasing octane number in gasoline; regenerating all recycling catalysts, quality of products being stable and easily operated, reducing sulfur of gasoline to a maximum limit; adding a cooling device so as to avoid coking when the catalyst contacts with oil-gas in high temperature and decrease of yield of light oil resulted by excessively high reaction temperature of gasoline upgrading, improving products distribution, being flexible to change catalyst-oil ratio and reaction temperature of catalytic cracking reaction. The invention also provides an easily operated process for FCC desulfurization with stronger desulfurizing ability, good selectivity of products and high light oil yield, which can realize 40-80% of FCC gasoline desulfurization. Furthermore, more than 80% of FCC gasoline desulfurization can be achieved if the process is applied in combination with some particular catalysts.

主权项

1. A catalytic cracking process for reducing sulfur content in gasoline, said process comprising:
feeding a heavy oil feed to a catalytic cracking device containing a heavy oil riser reactor, a first settler, a regenerator, a second settler, wherein the top outlet of the heavy oil riser reactor communicates with the first settler, and the bottom of the heavy oil riser reactor connects with the regenerator through a first regeneration inclined pipe, followed by a first regeneration stand pipe, said device comprises a fluidized bed reactor, wherein a top outlet of the fluidized bed reactor connects with the second settler, and a gasoline feeding inlet is deposited on the fluidized bed reactor, and a lift gas inlet is deposited on a vertical stand pipe below the fluidized bed reactor; the bottom of vertical stand pipe below the lift gas inlet of the fluidized bed reactor is connected with the regenerator through a second regeneration inclined pipe, a second regeneration stand pipe; the regenerated catalyst from regenerator flows into the heavy oil riser reactor and the fluidized bed reactor after cooling through a riser cooler and a fluidized bed cooler, said process further comprising the steps of; a) a step consisting essentially of obtaining under the condition of fluid catalytic cracking in the heavy oil riser reactor, a first reactant flow by reacting the heavy oil feed with a catalyst, and the first reactant flow is isolated in the first settler to obtain isolated spent catalyst and isolated oil-gas, the isolated oil-gas flows into a fractionating device to fractionate and the isolated spent catalyst is subjected to stripping in a stripping section of the first settler and flows into the regenerator, the spent catalyst is subjected to coke burning regeneration in the regenerator under the condition of regeneration of fluid catalytic cracking catalyst to obtain a regenerated catalyst; b) a step consisting essentially of providing a portion of the regenerated catalyst which flows back into the heavy oil riser reactor through the first regeneration stand pipe, the first regeneration inclined pipe, and the riser cooler, and another portion of the regenerated catalyst flows into the second regeneration stand pipe and then into the fluidized bed reactor by using a pre-lift medium through the second regeneration inclined pipe and the fluidized bed cooler; and c) a step consisting essentially of obtaining a second reactant flow by contacting a gasoline feed in the fluidized bed reactor with the regenerated catalyst from step a) under the condition that the temperature is 300-550° C., the ratio of the regenerated catalyst to the feed of gasoline is 1-15, and the space velocity is 4.0-60.0h−1, the second reactant flow is isolated in the second settler to obtain isolated spent catalyst and isolated oil-gas, the isolated oil-gas flows into the fractionating device to fractionate, and the isolated spent catalyst is subjected to a second stripping in a stripping section of the second settler and flows into the regenerator; the regenerated catalyst is recycled in step b).