Study On The Utilization Of Waste Heat Of A 300MW Heat Supply Unit Coupled Heat Pump

With the development and change of human society,energy has gradually become the material basis for people’s survival.At the same time,the progress of science and technology also promotes the exploration of energy.Conventional thermal power plants not only cause environmental pollution,but also cause a lot of heat loss caused by steam turbine exhaust,resulting in energy waste.If this part of waste heat is effectively recycled and low-quality exhaust steam is used for heating,it can not only effectively reduce the waste of energy in production,but also protect the environment,which is a powerful measure of energy conservation and environmental protection.Based on the current situation of waste heat recovery and utilization in thermal power plants in China,this paper analyzes the characteristics of the lithium bromide absorption heat pump system,studies the technical principle and thermodynamic characteristics of the absorption heat pump technology,and applies the heat pump technology in the waste heat recovery process of power plants,so as to demonstrate the feasibility of the heat pump technology.In this paper,the coupling absorption heat pump of 300MW heating unit applied in waste heat recovery technology of power plant is studied,and the recovery technology is optimized,which provides certain technical reference for engineering transformation and subsequent research.The main conclusions of this thesis are as follows:（1）On the premise of a certain amount of heat supply,the thermal performance of heat pump heating is better than that of steam extraction heating.When the total heat supply of the unit is fixed,the thermal performance of heat pump is better than that of steam extraction;when the heating conditions can meet the requirements of total heat supply,the absorption heat pump system should be preferred for heating.（2）The absorption heat pump technology is used to recover the exhaust steam waste heat.With the increase of the water supply temperature of the heat supply network,the thermal performance of the thermal power plant is optimized.When the water supply temperature of the heat supply network increases from 58℃to 80℃,the coal saving amount increases by about 1/3.The back pressure of the unit has little influence on the thermal performance of the heat pump heating system,but the comprehensive efficiency of the thermal power plant and the coal saving amount of the system Therefore,the unit back pressure should be as low as possible on the premise that the heat supply does not change.The increase of COP of heat pump is beneficial to the heating of thermal power plant and heat pump.When COP increases from 1.5 to 2.0,the heating loss directly decreases from 63.89GJ/h to 0.74GJ/h.（3）The utilization of exhaust steam and waste heat of heat supply unit coupled with absorption heat pump has increased the heating capacity of the unit.In this thesis,after the coupled absorption heat pump of 2×300MW heating unit,the external heating capacity can be increased by 130MW and the heating area can be increased by2.36 million square meters.（4）In the process of waste heat recovery of power plant,using heat pump technology can effectively improve the energy utilization rate of power plant,reduce the waste of energy in the process of power generation,and reduce the pollution of harmful gas and coal slag to the environment.In this paper,the 2×300MW heating unit is studied and reformed according to the actual situation.Under the rated heat supply condition,a single unit can recover 100t/h exhaust steam heat for heating,which reduces the coal consumption of the unit by 38.87g/k Wh,increases the heating and heating efficiency by 14.95%,and increases the efficiency of the whole plant by8%.Recovery of exhaust steam heating will save 71700 tons/year of standard coal,the reduction of CO₂emission is 165500 tons,the reduction of SO₂emission is 1700tons,the reduction of NO_xemission is 162.47 tons,the reduction of smoke and dust is1400 tons,and the reduction of ash and slag is 26800 tons.