Energy saving solutions for thermal power industry

In China, the actual thermal efficiency of large thermal power plants is only 40%, and that of nuclear power plants is less than 35%. More than 60% of the heat is taken away by cooling water, and a large amount of heat is discharged into the air environment through cooling circulating water in the form of condensation heat. The gap between the central heating supply of thermal power plants is growing. Due to the influence of coal control and the national 30 · 60 double carbon policy, the losses of heating enterprises are increasing year by year. Utilize the condensation heat and flue gas waste heat in a reasonable way, and recover this part of heat energy with heat pumps for industrial hot water or heating hot water, which can not only improve the comprehensive utilization rate of heat energy in thermal power plants, but also bring good economic and social benefits to the power plants, thus it can be seen that the recovery and utilization of waste heat in thermal power plants has great potential.

1. Use water source heat pump to extract low-grade heat from cooling circulating water, and produce 50-80 ℃ high-temperature water to directly supply heat to buildings, which can increase the heating capacity by more than 40%.

2. For (thermal) power plants with large amount of boiler make-up water, water source heat pump can be used to extract low-grade heat from cooling circulating water to heat boiler make-up water, thus reducing the amount of air extraction and improving power generation efficiency.

3. The absorption heat pump is used to extract the low-grade heat from the cooling circulating water, which can increase the primary heating network capacity by more than 30% under the condition that the gas supply volume of the main network remains unchanged.

Boiler flue gas waste heat recovery and utilization solution

Due to the shortage of energy, with the further development of energy conservation work, various new and advanced energy-saving furnace types are becoming more and more perfect, and the heat loss of the furnace is significantly reduced after the use of high-quality thermal insulation materials such as new refractory fiber. The use of advanced combustion devices strengthens combustion, reduces incomplete combustion and makes the air-fuel ratio more reasonable. However, the technology of reducing the heat loss of flue gas and recovering the waste heat of flue gas is still not progressing fast. In order to further improve the thermal efficiency of the kiln and achieve the purpose of energy saving and consumption reduction, the recovery of flue gas waste heat is also an important way to save energy.

Flue gas is the main way to waste energy for general energy-consuming equipment. For example, the energy consumption of boiler flue gas is about 15%, the ambient temperature in summer is often above 35 ℃, and the boiler flue gas temperature can reach above 165 ℃, accounting for 60%~70% of the overall heat loss of the boiler. At the same time, it also seriously affects the safe operation of flue gas desulfurization equipment. Except for the thermal power industry, the main energy consumption of such as the sizing machine, dryer and kiln in the printing and dyeing industry is through flue gas emissions, Therefore, the flue gas waste heat recovery and utilization solution is not only applicable to waste heat recovery and utilization in thermal power plants, but also applicable to other industrial boiler application enterprises such as textile industry and smelting industry.

Advantages and characteristics of the scheme

1. This system technology can reduce the flue gas temperature to lower (such as about 30 ℃) and recover more heat.

2. It can not only recover the sensible heat of flue gas, but also greatly reduce the exhaust temperature and recover the latent heat.

3. The reduction of flue gas temperature can play the role of whitening.

4. This heat recovery system technology plays a deep strengthening role in desulfurization and denitrification, and reduces the emission of pollutants.