A co that utilizes lng cold energy and exploits hydrate 2 Capture device and capture method thereof

Abstract

The invention relates to the technical field of oil-gas storage and transportation engineering, and discloses a CO2 capturing device and capturing method achieving LNG cold energy utilization and hydrate exploitation. The device comprises an LNG vaporization system, a BOG treatment system and a CO2 recovery system. The LNG vaporization system comprises a liquid phase area temperature increase subsystem, a gas-liquid two-phase area temperature increase subsystem and a gas phase area temperature increase subsystem which are connected in sequence. The gas-liquid two-phase area temperature increase subsystem is connected with the BOG treatment system. A CO2 vaporization pressurization output system is connected with the BOG treatment system and the CO2 recovery system, so that flue gas CO2 generated by the BOG treatment system is injected into a hydration reservoir so as to replace CH4 gas and part of flue gas CO2 gas, and the CH4 gas and the flue gas CO2 gas are conveyed to the CO2 recovery system to be subjected to further recovery treatment. The CO2 recovery system is connected with the liquid phase area temperature increase subsystem and the gas-liquid two-phase area temperature increase subsystem. The CO2 capturing device achieving LNG cold energy utilization and hydrate exploitation has the advantages that the LNG cold energy utilization rate is high and CO2 is effectively captured.

Description

technical field [0001] The invention relates to the technical field of oil and gas storage and transportation engineering, in particular to a CO 2 Capture device and capture method thereof. Background technique [0002] LNG is a low-temperature liquid mixture at -162°C under normal pressure. When gasifying each ton of LNG, it can generate about 240kWh of cold energy. Reasonable use of this part of cold energy can produce considerable economic benefits. Among them, cold energy can be used in power generation, low-temperature cold storage and ice storage and other fields. The temperature of LNG rises from -162°C to 10°C during the release of cold energy, and the temperature span is large. Therefore, if a single-stage Rankine cycle power generation system is established, the heat transfer temperature difference of the Rankine cycle power generation system is large, which is likely to cause cold. The loss of exergy is large, and it is difficult to improve the utilization effic...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a CO 2 The capture device and its capture method solve the problem of injecting replacement gas into the hydrate layer during the process of hydrate replacement mining in the prior art, and the replacement gas enters the hydrate cage to replace the CH in the hydrate cage. 4 (methane), so as to achieve the purpose of mining. In this process, the existing technology cannot efficiently utilize the cold energy of LNG (liquefied natural gas), and at the same time, it cannot efficiently utilize BOG (boil-off gas), and in the process of CO 2 Good storage cannot be achieved after liquefaction

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