Refined heavy-hydrocarbon removal system for recovering LNG/LPG/NGL from petroleum associated gas

Abstract

The invention provides a refined heavy-hydrocarbon removal system for recovering LNG / LPG / NGL from petroleum associated gas, which comprises a raw material associated gas inlet pipeline, an LPG cold box, a low-temperature separator and a refined removed heavy hydrocarbon absorption tower, wherein an outlet of a lower box of the LPG cold box is connected with the refined removed heavy hydrocarbon absorption tower by a pipeline, an outlet at the bottom of the refined removed heavy hydrocarbon absorption tower is connected with a tower-bottom liquid phase pipeline, an outlet at the top of the refined removed heavy hydrocarbon absorption tower is connected with a lower middle box of the LPG cold box by a pipeline, the lower middle box is connected with the low-temperature separator by a pipeline, the bottom of the low-temperature separator is connected with an absorbent booster pump by a pipeline, and the absorbent booster pump is connected with the refined removed heavy hydrocarbon absorption tower by a pipeline. By using the characteristic that the equilibrium constants of hydrocarbon substances at different temperatures and consisting of different components are different, the system dilutes the heavy hydrocarbon content of associated gas, thereby achieving the purpose of reducing the heavy hydrocarbon content of dry gas; the temperature of associated gas is reduced two times by using the cold box so as to meet different temperature requirements of absorption and separation; and due to the adoption of the absorption tower, the precision of heavy hydrocarbon removal is improved.

Description

technical field [0001] The invention belongs to the petroleum field, and in particular relates to a system for refining and removing heavy hydrocarbons used for recovering LNG / LPG / NGL from petroleum associated gas. Background technique [0002] Associated gas is oil associated gas in oilfields, which is the volatile part of crude oil. It is a petroleum-based flammable gas. It is a high-quality fuel and chemical raw material. [0003] In the past, due to the scattered and small amount of associated gas, the complex treatment process and high investment, most of them were treated directly or burned, which not only polluted the environment, but also wasted resources. At the same time, there were potential safety hazards. emissions, low-carbon economy and green development are inconsistent. [0004] Associated gas has high economic value. After the associated gas is treated, the recoverable economic products include: LPG (liquefied petroleum gas), NGL (stable light hydrocarbon...

AI Technical Summary

Problems solved by technology

At present, this process technology is relatively lacking in application performance and experience in the world. The production of LNG products has strict requirements on the content of heavy hydrocarbons. When the content of heavy hydrocarbons exceeds a certain limit, it will freeze and block the cold at -160°C Tanks and valve pipelines make it difficult for the ultra-low temperature system to operate stably

At present, there are few similar experiences that can be used for reference, and there is still a blank in this field in China

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