Development of integrated technology for waste heat recovery from humid flue gas of hot water boiler

Abstract

Summary For coal‐fired hot water boilers, we developed a comprehensive waste heat recovery system coupled with a packed tower, industrial steam turbine, and absorption heat pump, which can directly reduce the auxiliary power consumption, realize energy cascade utilization, and waste heat recovery. The ASPEN Plus software was used to simulate the packed tower, absorption heat pump, and industrial steam turbine system. The design parameters of the system were obtained and the operation characteristics of the system under load rates of 25%, 50%, 75%, and 100% were investigated, the feasibility of steam subsystem transformation was also analyzed. Taking a 140 MW coal‐fired boiler as an example, in the range of 25%~100% load rate, the direct energy saving can reach 118 to 523 kW∙h, the waste heat recovery power is 2.7 to 11.4 MW, and the coal saving can reach 374 to 1605 kg/h, resulting in energy and resource consumption reduction effect, the system also has CO2 and pollutant emission reduction effect. The RadFrac model can be used in packed tower design, the system can work well under variable load conditions.

Experimental Investigation into Flue Gas Water and Waste Heat Recovery Using a Purge Gas Ceramic Membrane Condenser

“…For a long time, many researchers have been concerned with the flue gas water and waste heat recovery technology research. − The low-temperature condensation method − uses a cooling medium to reduce the flue gas temperature, forcing the water vapor to condense and precipitate in the flue gas, thus achieving sensible heat recovery and latent heat recovery. The liquid absorption method − uses a dehumidification solution with low saturated water vapor pressure to absorb water vapor from the flue gas.…”