Method and device capable of increasing capture rate of carbon dioxide in oilfield carbon dioxide flooding produced gas

Abstract

The invention relates to a method and a device capable of improving the capture rate of carbon dioxide in oilfield carbon dioxide flooding produced gas. The method comprises the following steps: pre-cooling feed gas; cooling CO2; flashing and separating the feed gas; carrying out low-temperature stripping; and recycling overhead gas. The device comprises a feed gas pre-cooler, a CO2 cooler, a flash tank, a stripping tower, a tower bottom reboiler, a tower top cooler, an overhead gas separator, an overhead gas compressor and a compression outlet cooler; the tower bottom reboiler is connected with the feed gas pre-cooler through a pipeline; the feed gas pre-cooler is connected with the CO2 cooler through a pipeline, the CO2 cooler is connected with the flash tank through a pipeline, the flash tank is connected with the stripping tower through a pipeline, the stripping tower is connected with the overhead gas separator through a pipeline, and the overhead gas separator is connected with the tower top cooler through a pipeline. Compared with an existing low-temperature rectification process, an overhead gas recovery process is developed, the cold energy is recycled, cyclic utilizationof CO2 is realized, emptying frequency is reduced and the CO2 recovery rate is increased.

Description

technical field [0001] The invention relates to the field of carbon dioxide separation and recovery, in particular to a method and device capable of increasing the carbon dioxide capture rate in oilfield carbon dioxide flooding produced gas. Background technique [0002] CO 2 is a typical greenhouse gas, CO 2 Used in oil field flooding can not only enhance oil recovery, but also realize the greenhouse gas CO 2 The permanent storage not only improves the economic benefits, but also produces a wide range of social benefits. But using CO in the oil field 2 During oil flooding, part of the CO 2 It will be extracted with the oil and gas production process, resulting in a large amount of CO contained in the produced gas 2 , the part CO 2 It needs to be captured and recycled, otherwise it will affect the storage effect and reduce CO 2 Drive environmental benefits. Cryogenic distillation process is to capture CO 2 Flooding high concentration CO in produced gas 2 A common p...

AI Technical Summary

Problems solved by technology

But using CO in the oil field 2 During oil flooding, part of the CO 2 It will be extracted with the oil and gas production process, resulting in a large amount of CO contained in the produced gas 2 , the part CO 2 It needs to be captured and recycled, otherwise it will affect the storage effect and reduce CO 2 Drive environmental benefits

Cryogenic distillation process is to capture CO 2 High CO concentration in produced gas flooding 2 A common process that can produce more than 96% high-purity CO 2 Liquid products; but the process also has low capture yield, CO 2 The disadvantages of high venting ratio and high unit capture energy consumption reduce the oilfield CO 2 Benefits of flooding

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