Combined power circulating method capable of catching carbon dioxide (CO2) by using LNG (Liquefied Natural Gas) cold energy and system thereof

Abstract

The invention discloses a combined power circulating method capable of catching carbon dioxide (CO2) by using LNG (Liquefied Natural Gas) cold energy and a system thereof. The system comprises an air separation device, an oxygen-enriched-combustion gas turbine circulation device, a high-pressure steam power circulation device, a CO2 separation and liquefaction device and an LNG cold energy power circulation device, wherein the air separation device, the oxygen-enriched-combustion gas turbine circulation device, the high-pressure steam power circulation device, the CO2 separation and liquefaction device and the LNG cold energy power circulation device utilize the LNG cold energy. According to the method and the system, electricity and high-temperature fume which is rich in CO2 and water are generated from LNG through the oxygen-enriched-combustion gas turbine circulation device, and heat is recovered from the fume through the high-pressure steam power circulation device, so as to produce high-temperature and high-pressure steam with the pressure over 18MPa and increase the power generation efficiency of natural gas; moreover, the LNG cold energy is sequentially applied to the air separation device, the LNG cold energy power circulation device and the CO2 separation and liquefaction device, and the energy consumption for CO2 catching is lowered by making full use of the LNG cold energy, so that combined power cycle has relatively high power generation efficiency and relatively high CO2 catching rate, and the efficient utilization of the LNG cold energy is realized.

Description

technical field [0001] The invention belongs to the field of liquefied natural gas cold energy utilization and carbon dioxide emission reduction, and in particular relates to a combined power cycle method and system for capturing carbon dioxide by utilizing liquefied natural gas cold energy. Background technique [0002] Climate change is becoming a major challenge to the sustainable development of human society. Since 1750, the world has emitted more than 1 trillion tons of carbon dioxide (CO 2 ), of which emissions from developed countries account for about 80%. Due to the emission of greenhouse gases, the average global surface temperature has risen by 0.74°C in the past century. Studies have shown that if the temperature rises by 4°C, it may cause irreversible damage to the global ecosystem. In the face of this common threat to the survival and development of mankind, from the United Nations Framework Convention on Climate Change to the Kyoto Protocol to the Bali Roadm...

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Problems solved by technology

[0015] In order to overcome the above-mentioned existing utilization of liquefied natural gas (LNG) cold energy to capture carbon dioxide (CO 2 ) in the combined power cycle, the energy consumption of oxygen production is high, the cold energy consumption of LNG is large, and the capture unit CO 2 Consuming too much cold energy of LNG, etc., the object of the present invention is to provide a combined power cycle method for capturing carbon dioxide by utilizing the cold energy of liquefied natural gas, through system integration and optimized design, fully and efficiently utilize the cold energy of LNG to reduce Oxygen production by air separation, CO in flue gas 2 Separation and liquefaction of reduced power cycle capture CO 2 At the same time, make full use of the high temperature and high pressure steam generated in the waste heat boiler due to the high exhaust gas temperature of the gas turbine, so as to improve the power generation efficiency of the system

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