Fuel cell and organic Rankine cycle combined power generating system based on LNG (Liquefied Natural Gas) cold energy utilization

Abstract

The invention discloses a fuel cell and organic Rankine cycle combined power generating system based on LNG (Liquefied Natural Gas) cold energy utilization. The fuel cell and organic Rankine cycle combined power generating system comprises a solid oxide fuel cell and gas turbine combined cycle system, an organic Rankine cycle system and an LNG cold energy source, wherein un-reacted fuel in an SOFC (Solid Oxide Fuel Cell) and air combust in a rear combustion chamber to generate a high-temperature and high-pressure gas which enters the gas turbine for doing work and outputting electric energy; high-temperature exhaust gas in the gas turbine sequentially preheats the air, fuel and water; the organic Rankine cycle system is used for recycling low-temperature flue gas waste heat which is left after being used for preheating the air, the fuel and the water; the low-temperature flue gas waste heat is converted into electric energy for outputting, so that the cascade utilization of energy is realized; the LNG cold energy source as a cold source of organic Rankine cycle is used for condensing exhausted gas of an organic working medium turbine, so that back pressure of the organic working medium turbine is remarkably reduced and power output of the organic Rankine cycle is increased; and meanwhile, the cold energy of the LNG is recycled. According to the fuel cell and organic Rankine cycle combined power generating system disclosed by the invention, the conversion efficiency of energy source can be remarkably improved, the discharge of pollutants is reduced and the performances of the system are improved.

Description

technical field [0001] The invention belongs to the field of high-temperature and medium-low temperature heat energy recovery and power engineering, and relates to a fuel cell and organic Rankine cycle combined power generation system based on cold energy utilization. Background technique [0002] Traditional fossil fuels, including coal, oil, and natural gas, have limited reserves, and most of them are used in the form of combustion, which not only makes energy utilization efficiency limited and leads to energy waste, but also inevitably produces a large amount of pollutant emissions. The solid oxide fuel cell is a power generation device that efficiently and environmentally friendly converts the chemical energy present in the fuel and the oxidant into electrical energy. The hydrogen in the fuel is directly converted into electrical energy by means of the electrolyte and oxygen in the air. It is a new power generation method that can well solve the contradiction between fos...

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Problems solved by technology

[0006] Aiming at the defects or deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a fuel cell and organic Rankine cycle combined power generation system based on LNG cold energy utilization, which utilizes the low-temperature waste heat of gas turbines and simultaneously utilizes the cold energy of liquefied natural gas. It can greatly increase the power generation of the system, realize the cascade utilization of energy, improve the energy utilization rate, reduce the air pollution, and meet the needs of the country for energy conservation and emission reduction.

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