Thermal power generation system based on high-moisture lignite pre-drying upgrading and recovering technology

Abstract

The invention relates to a thermal power generation system based on a high-moisture lignite pre-drying upgrading and recovering technology. The thermal power generation system comprises a boiler, a turbine, a condenser, a condensation pump, a low pressure heater, a deaerator, a water feed pump, a high pressure heater, a wet coal bin, a wet coal feeder and a coal mill and is characterized in that a lignite pre-drying device, a drain pump, a dry coal feeder, a dust remover and a heat energy and waste water recovering device are additionally arranged in the power generation system. The invention improves the energy density of fire coal and accordingly increases the efficiency of the boiler, and is capable of reducing the investment of the boiler and a milling system by a larger extent, simultaneously reducing the plant power utilization ratio, further improving the energy source comprehensive utilization efficiency of a thermal power generation plant, recovering a great deal water by using coal to produce water and saving precious water resources. The invention achieves the effects of high efficiency, energy saving, water saving and emission reduction and accords with the industrial policy of developing the low-carbon economy in China.

Description

technical field [0001] The invention belongs to the field of coal-fired thermal power generation, and relates to the improvement of a pulverizing system of a boiler and a heat recovery system of a steam turbine. Background technique [0002] my country's proven reserves of lignite resources amount to more than 130 billion tons, accounting for 13% of the country's coal reserves. Lignite is the youngest coal among raw coals, its volatile content is generally 40% to 50%, the total moisture can generally reach 20% to 50%, the air-dried base moisture is 10% to 20%, and the low calorific value is generally only 7 to 15MJ / kg. Because lignite has high water content, low calorific value, easy weathering and spontaneous combustion, and is difficult to wash and store, the transportation cost per unit of energy is high, and the economy of long-distance transportation is poor, which greatly restricts the mining and utilization of lignite. A low-grade fuel that is burned to generate el...

AI Technical Summary

Problems solved by technology

Due to the high moisture content of lignite itself, the loss of boiler exhaust smoke is larger compared with low moisture coal, the thermal efficiency of boiler direct combustion is low, the economy is limited, and the emission of greenhouse gases is also large

In addition, the calorific value of high-moisture lignite is low, which makes the boiler body bulky and expensive; the capacity of boiler auxiliary equipment is relatively large, and the plant power consumption rate is high

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