Thermal circulation process of gas turbine based on pure oxygen or oxygen-enriched combustion

Abstract

The invention discloses a thermal circulation process of a gas turbine based on pure oxygen or oxygen-enriched combustion, which comprises the following steps: compressing liquid fuel or gas; compressing oxygen gas or oxygen-enriched air; carrying out mixed combustion of the liquid fuel or the gas and the oxygen gas or the oxygen-enriched air; spraying water for controlling temperature; expanding high temperature and high pressure flue gas after combustion in the gas turbine for applying work; cooling most of water vapor in tail gas with circulating water in a condenser, wherein the condensed water circulates to a combustion chamber to be used for spraying water for controlling temperature, and the non-condensable gas is extracted by a vacuum pump; or exhausting gas under normal pressure without the use of the vacuum pump. By adopting direct combustion of the pure oxygen or the oxygen-enriched air and adopting the water spraying mode to replace excess air for controlling temperature, the air inflow is small, the amount of compression of a compressor is small, the restriction of the optimal pressure gas ratio is eliminated, the circulating intake pressure is improved, the non-condensable gas in the tail gas is little, and the exhaust pressure can be reduced through vacuum condensation. Because the process has high circulating intake pressure and low exhaust pressure, the expansion ratio of the gas turbine is improved, thereby improving the generating efficiency.

Description

technical field [0001] The invention relates to the technical field of thermal cycle, in particular to the technical field of gas turbine thermal cycle. Background technique [0002] Thermal cycle is an important step in fossil energy power generation and one of the core technologies in the power industry. Its thermodynamic process mainly includes compression, isobaric heat absorption, expansion work, and isobaric heat release. [0003] At present, there are two main forms of thermal cycle power generation: one is closed cycle, which is the commonly used coal-fired boiler steam turbine generator set at present, and the other is open cycle, which is the commonly used gas turbine generator set at present. The combination is a combined cycle generator set. [0004] The main disadvantages of the above existing common processes are as follows: [0005] Closed cycle, since water vapor is used as the heat carrier, indirect heating is adopted, and the temperature of the cycle inl...

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Problems solved by technology

[0006] Open cycle, because it adopts direct heating cycle, the temperature can be very high, about 1400 ℃, but because it adopts the method of passing in excess air to control the temperature after combustion, the air compression capacity is huge, and the compressor has an optimal Compression ratio limitation

The general cycle pressure is only one-tenth of that of the closed cycle. At the same time, because the tail gas is mostly non-condensable gas and the exhaust gas is exhausted at normal pressure, the expansion ratio cannot be increased, resulting in high exhaust temperature and power generation efficiency of only about 40%.

The reason for the low power generation efficiency of the open cycle is that the cycle intake pressure is low, and the atmospheric pressure exhaust results in high exhaust temperature.

This is firstly due to the fact that the performance of the existing materials restricts the unlimited increase of the cycle temperature; secondly, because the existing process uses excess air to control the gas temperature, due to the huge amount of air compression, the large compression power consumption, and the existence of compressor compression efficiency The influence of these two factors, the expansion efficiency of the gas turbine, so each cycle temperature corresponds to an optimal compression ratio, which affects the improvement of the efficiency of the gas turbine

[0007] Combining closed cycle and open cycle, the open cycle gas turbine is first used to generate electricity, and the exhaust gas is then passed through the boiler to generate steam, which is used for closed cycle steam turbine power generation, which is combined cycle power generation. The power generation efficiency can currently approach 60%. improved, but the process is long and the investment is large

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