Open type heat pump system capable of simultaneously recovering water and latent heat in high-humidity flue gas

Abstract

The invention discloses an open type heat pump system capable of simultaneously recovering water and latent heat in high-humidity flue gas;a flue gas inlet of an absorption tower is communicated with a high-humidity flue gas exhaust pipeline, a flue gas outlet of the absorption tower is communicated with the atmospheric environment, a dilute solution outlet of the absorption tower is divided into two paths, the first path is communicated with a dilute solution inlet of a solution tank, the second path is communicated with a dilute solution inlet of the regenerator through the hot side of a solution heat exchanger; a concentrated solution outlet of the regenerator is communicated with a concentrated solution inlet of a solution pool through a pipeline via the cold side of the solution heat exchanger; a dilute solution outlet of the solution pool is communicated with a dilute solution inlet of the absorption tower after passing through the hot side of a precooler through a pipeline. The solution circulation of the absorber and the solution circulation of the regenerator are decoupled, and two independent solution circulations are independently arranged, so that the variable working condition performance of the open type heat pump is greatly improved; and the solution pool is arranged, so that the start-stop characteristic of the open-type heat pump is improved at the same time. Compared with an original open type heat pump, the open type heat pump can be flexibly adjusted under variable working conditions, and the absorber and the regenerator can efficiently operate at the same time.

Description

technical field [0001] The invention belongs to the technical field of flue gas dust removal and waste heat recovery, and relates to an open heat pump system, in particular to an open heat pump system in which water in high-humidity flue gas and waste heat are recovered in cooperation. Background technique [0002] The waste heat recovery and utilization technology of industrial wet flue gas, represented by wet desulfurization of coal-fired boiler exhaust and dusty flue gas emitted by industrial processes, has developed rapidly. The low-temperature waste heat of wet flue gas is dominated by latent heat. At 50°C, the latent heat of urban heating gas boilers with smoke exhaust has a relatively high proportion of waste heat. The latent heat of exhaust smoke is about 10% of the low calorific value of natural gas. If recycling can significantly improve the utilization of natural gas Rate. [0003] The use of partition wall heat exchangers is currently the main method for flue ga...

AI Technical Summary

Problems solved by technology

[0006] In contrast, the latent heat recovery of flue gas by a closed heat pump is limited by the dew point temperature, and the temperature of the flue gas must be lowered below the dew point temperature. The sensible heat is not effectively utilized, and the cascade utilization of flue gas heat cannot be realized. If the refrigerant water is used to recover the waste heat of the flue gas and the intermediate heat exchange link is added, the temperature of the recovered heat will be further reduced. In addition, the closed heat pump needs to be driven by an external heat source (such as Gas, steam), affecting the overall efficiency of the system

In addition, after using the closed heat pump to recover the waste heat of the flue gas, the temperature of the flue gas is low and in a state of moisture saturation, which affects its thermal discharge and causes the flue gas to condense at the flue and chimney mouth

[0007]In the existing open heat pump process, the concentrated solution from the regenerator is sent directly to the absorber after being cooled, and the flow rate of the solution at the inlet of the absorber is the same as the flow rate of the solution at the outlet of the regenerator , limited by this, the adjustment performance of the open heat pump under variable working conditions is poor, and it is difficult for the absorber and the regenerator to achieve better performance at the same time: when the external parameters increase (the humidity content of the flue gas increases), the inlet liquid of the absorber is increased. The gas ratio (the ratio of the mass flow rate of the solution at the inlet of the absorber to the mass flow rate of the imported dry-based flue gas) is used to ensure the flue gas treatment effect (discharge humidity remains unchanged), and the solution flow rate of the regenerator also increases accordingly, increasing the liquid film transfer in the regenerator mass drag (increased liquid film thickness), reduced regeneration performance

Increasing the liquid-to-gas ratio improves absorber performance but reduces regenerator performance; reducing solution flow (equivalent to reducing absorber liquid-to-gas ratio) improves regenerator performance but reduces absorber performance

Images