Heat-pipe-based complementary electricity generation system for preheating condensed water of coal-fired unit through geothermal energy

Abstract

The invention discloses a heat-pipe-based complementary electricity generation system for preheating condensed water of a coal-fired unit through geothermal energy. The system is mainly composed of a coal-fired generator unit subsystem and a geothermal energy preheating condensed water subsystem which are connected in parallel, and mainly comprises a coal-fired boiler, a turbine, a generator, a condenser, a condensate pump, a low-pressure heater, a deaerator, a high-pressure heater, a heat pipe, a heat pipe heat exchanger, a water pump and valves. Heat-pipe working medium absorbs geothermal energy at the evaporation section to form steam and is conveyed to the condensation section of the heat pipe heat exchanger through pressure difference, condensed water shunted by a certain stage of low-pressure regenerator outlet is heated, the condensed water heated to the corresponding temperature is injected into a coal-fired unit regeneration system again, steam extraction of the turbine is replaced, the generated energy of the coal-fired unit is increased, the shunting and re-injection positions and flows of the condensed water are adjusted through the valves, and gradient utilization of energy is achieved. The investment of power equipment is reduced, a re-injection well does not need to be dug, pump power is not consumed and corrosion and scaling are not generated in the geothermal energy development process, and energy conservation and emission reduction of a thermal power generating unit and large-scale development of the geothermal energy are facilitated.

Description

technical field [0001] The invention belongs to the field of renewable energy utilization, and relates to a novel complementary power generation system that efficiently utilizes geothermal energy through heat pipes and preheats condensed water of coal-fired units to increase the power generation of coal-fired units. Background technique [0002] my country's primary energy is mainly coal, and the total coal consumption has increased by 157% in the past 10 years. In 2012, coal consumption accounted for 50.2% of the global coal consumption. However, the extensive use of coal has brought serious environmental pollution, such as SO 2 , NO x , CO 2 , PM2.5, heavy metals and a large amount of dioxin emissions. The emission of a large amount of greenhouse gases has promoted global warming, causing the frequency and intensity of disastrous weather and abnormal climate to increase continuously in recent years, resulting in major changes in the spatio-temporal pattern of water reso...

AI Technical Summary

Problems solved by technology

The organic Rankine cycle (ORC) is mainly used for medium and low temperature geothermal power generation. However, since the temperature of medium and low temperature geothermal energy is generally below 180°C, the power generation efficiency of the organic Rankine cycle does not exceed 12%.

In order to ensure the sustainable exploitation of geothermal resources and the balance of groundwater, in the traditional way of geothermal utilization, geothermal water needs to be recharged, so the development of geothermal energy needs to dig production wells and reinjection wells, and the cost of geothermal well exploitation is high

Geothermal wells are often as deep as 1-3km, and the pump power consumption is large

Geothermal water is rich in minerals and silicates, etc. When the reinjection temperature of geothermal water is too low, it will cause serious scaling in heat exchangers, valves, and reinjection wells. In addition, geothermal water will also carry corrosion Sexual components, which affect the normal operation of equipment and the efficient use of geothermal energy

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