Catalytic cracking absorption stabilization system having gasoline cutting and process producing more propene and reducing alkene

Abstract

The invention relates to a catalytic cracking adsorption-stabilization system with gasoline cutting and a technique for increasing the content of propylene and reducing the content of olefins. The catalytic cracking adsorption-stabilization system and the technique are as follows: a gasoline cutting tower is connected to the rear of a double-tower flow stabilizer; a stream of gasoline is stabilized at the bottom of the stabilizer and enters into the central section of the increased gasoline cutting tower at a temperature of between 105 and 115 DEG C; after the gasoline is cut by the gasoline cutting tower, a part of light gasoline on the top of the tower enters into a reaction-regeneration system for remixing; heavy gasoline at the bottom of the tower is mixed with the light gasoline at a temperature of between 35 and 45 DEG C after a heating desorption tower 10 is fed; and mixed streams pass through a water cooler and are outputted from the device when the temperature is reduced to be lower than 40 DEG C. By utilization of the flow of the catalytic cracking adsorption-stabilization system and the technique, the light gasoline after cutting is remixed, thereby the content of the propylene can be increased, thereby being favorable for solving the problem of insufficient propylene products in the petrochemical industry of China. Moreover, because the gasoline cutting is clear, the content of olefins in the gasoline is greatly reduced and the quality of the gasoline products is obvious improved. The energy-saving technique can reduce the energy consumption during the stable absorption process and reduce the operating cost.

Description

technical field [0001] The invention is aimed at the catalytic cracking system in petroleum refining, and in particular relates to a catalytic cracking absorption stabilization system with gasoline cutting and a process for producing more propylene and reducing olefins. Background technique [0002] The catalytic cracking unit is one of the main refining units. It is an important device for lightening heavy oil and producing liquefied gas, gasoline and diesel. The absorption stabilization device is a post-processing system in the catalytic cracking unit, which separates the crude gasoline and rich gas from the top of the catalytic fractionation tower into product liquefied gas and stable gasoline, and at the same time obtains dry gas as a by-product. The product quality and energy consumption of the absorption stabilization unit have a very important impact on the economic benefits of the entire catalytic cracking unit. [0003] The old devices of the absorption-stabilizat...

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Problems solved by technology

[0006] Although researchers have proposed different transformation schemes for the double-tower process, so far, the following problems still exist in the double-tower process: (1) Excessive desorption in the desorption tower, resulting in a large amount of C3 in the absorption tower and desorption tower , carbon four-component cycle, increasing the energy consumption of the process

(2) Only raw crude gasoline and rich gas are separated into dry gas, liquefied gas, and stable gasoline products, making it difficult to adjust the total olefin content of stable gasoline products

(3) The absorption effect of the absorption tower is not ideal, and the dry gas contains a large amount of liquefied gas components, resulting in the loss of liquefied gas

(4) The separation capacity of the stabilization tower is not enough, the high content of carbon five components in the liquefied gas makes the quality unqualified, and the gasoline yield decreases

(5) The content of C4 in stable gasoline products is high, resulting in unqualified gasoline vapor pressure

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