Device and method for producing clean gasoline and increasing propylene yield through catalytic cracking and hydrogenation

Abstract

The invention discloses a device and method for producing clean gasoline and increasing propylene yield through catalytic cracking and hydrogenation. The device comprises a reaction-regeneration system, a fractionating system, an absorption stable system and a hydrofining unit. The method comprises the following steps: adding a gasoline fractionating tower to the top of a catalytic cracking fractionating tower to divide crude gasoline into a light fraction and a heavy fraction, wherein the heavy gasoline enters the hydrogenation unit for refining, and one part of the light gasoline enters the absorption stable system to obtain stable light gasoline, and the other part of the light gasoline directly returns to the upper part of a catalytic cracking riser reactor to be cracked to increase the propylene yield under a relatively harsh reaction condition; and finally, blending the stable light gasoline and the modified heavy gasoline to obtain the product of clean gasoline. By adopting the method, the catalytic cracking gasoline is efficiently modified, the propylene yield is increased, and the catalyst-oil ratio of a catalytic cracking device can be increased to promote the conversion of heavy petroleum hydrocarbon; and meanwhile, the load and energy consumption of the absorption stable system are reduced, the process is simplified, the synergistic effect between the two devices of catalytic cracking and hydrofining is enhanced, and the processing cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a device and a process for jointly producing clean gasoline and increasing the production of propylene by catalytic cracking and hydrofining. Background technique [0002] In my country, catalytic gasoline provides nearly 80% of the blending components of finished gasoline, but also introduces more than 90% of sulfur and olefins. The poor quality of raw materials not only increases the sulfur content of catalytic gasoline, but also increases the olefin content of gasoline. At present, the olefin content of catalytic gasoline in my country is generally 40~60 vol.%, which is far from meeting the requirements of gasoline standards. Therefore, the key to improving the quality of gasoline in my country at this stage is to reduce the olefin content and sulfur content of FCC gasoline. [0003] Propylene is an important basic raw material for organic synthesis...

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Problems solved by technology

However, none of the above patents involves the olefin-reducing treatment of olefin-rich light gasoline, which makes heavy-distillate gasoline need to reach a certain olefin saturation rate in the hydrogenation process to make the final product gasoline meet the requirements of the latest gasoline standards

Another problem is that the above patents all cut the catalytic cracking stable gasoline, so the catalytic gasoline may have been cut twice, thereby increasing energy consumption and equipment investment

Patent CN101294108A proposes to separate light and heavy fractions of catalytic gasoline in the separation system of catalytic cracking products, and then carry out hydrofining of heavy fractions, but it does not involve the improvement of absorption-stabilization system flow and the treatment of light gasoline rich in olefins De-alkene upgrading does not involve the systematic coupling of the two processes of catalytic cracking and hydrofining

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