Direct heat utilization
The energy-consuming process of transferring waste heat energy directly to its own process through heat exchange equipment, which is one of the direct and efficient methods of waste heat recovery. Due to the low temperature of waste heat resources, it is necessary to find a suitable utilization occasion, but also consider the loss factor in the process of transmission.
The more common ones are: circulating water for heating and heating, boiler flue gas for waste heat air, heating furnace flue gas waste heat for heating materials, etc.
Refrigeration and heating
In the case of direct heat exchange without suitable utilization occasions, low-temperature waste heat can also be used for absorption refrigeration or heat pump heat production, changing the level of waste heat energy.
The use of power plant circulating water as the heat source of the heat pump, using a small amount of pumped steam as the driving energy, the use of heat pumps to raise the temperature of circulating water to 95 ℃ after sent to the city heating network, energy-saving effect is significant.
Chemical enterprises need more process devices for refrigeration, using lithium bromide absorption refrigeration units, using waste heat as a heat source to produce cold for production use, is also a very reasonable energy-saving measure to use low-temperature waste heat.
Thermal power conversion
Thermal power conversion is the conversion of low-grade waste heat resources into mechanical or electrical energy to be used. Generally speaking, if the low-grade waste heat resources in the "direct thermal utilization" or "cooling and heating" two ways are more difficult, thermal power conversion is an option. If only mechanical energy is converted, a reasonable mechanical load is required at the waste heat resource utilization site. Further conversion to electrical energy allows for a more flexible use of a slightly more distant transmission.
The main technical means of thermal power conversion are screw expander power generation technology, steam turbine power generation technology, saturated steam power generation \ dragging technology, etc.