Lean gas reabsorption unit and process in an absorption stabilization system

Abstract

The invention belongs to the technical field of petrochemical engineering and particularly relates to a re-absorbing unit and procedure for absorbing lean gas in a stable system. The unit comprises an absorbing tower, a re-absorbing tower, a liquid jet gas pump and a lean oil pump. An inlet of the liquid jet gas pump is connected to the top of the absorbing tower and the lean oil pump. An outlet of the liquid jet gas pump is connected to the bottom of the re-absorbing tower. The procedure includes the steps that lean gas from the absorbing tower and part of lean oil boosted through the lean oil pump enter the liquid jet gas pump, part of the lean oil boosted through the lean oil pump is directly sucked into the lean gas as work fluid of the liquid jet gas pump and enters the bottom of the re-absorbing tower in a full-mixed state through mass and momentum transfer, and gas and liquid separation is achieved; the other part of lean oil enters the re-absorbing tower from the top and flows through a tower plate from top to bottom, and the portion, larger than or equal to C3, of gas ascending from the tower bottom is further absorbed. Because of enhancement of gas and liquid mass transfer and increase of absorbing pressure, the number of re-absorbing tower plates is reduced, the lean oil amount is reduced, and economic benefits are good.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a lean gas reabsorption unit and process in an absorption stabilization system. Background technique [0002] The absorption stabilization system is an important part of crude oil secondary processing equipment such as catalytic cracking, delayed coking, hydrocracking, etc., and occupies an important position in petrochemical industry. Its function is to use the method of absorption and rectification to separate the rich gas and crude gasoline (or crude naphtha) in the main fractionation tower system into dry gas, liquid hydrocarbons and stable gasoline (or naphtha) with qualified vapor pressure. [0003] Absorption and stabilization system is mainly composed of rich gas compressor, condensed oil tank, absorption tower, desorption tower, stabilization tower, reabsorption tower and corresponding cooling equipment. Among them, the absorption tower is to ...

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Problems solved by technology

[0005] In the above process, the absorption oil introduced from the upper part of the tower is sprayed on the first tray through the distributor, and then flows down along the flow channel in the tower to contact the rising gas successively, which is limited by the tray structure and non-forced flow , the gas-liquid two-phase contact is insufficient

Therefore, in order to ensure the qualified dry gas quality, the number of trays has to be increased, resulting in tower height, many trays, and large investment; at the same time, it also increases the amount of lean oil in the cycle, increasing the processing load and energy consumption of the main fractionating tower system

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