A boiler flue gas deep waste heat recovery system and method

Abstract

The invention discloses a boiler smoke deep waste heat recycling system and method. Primary net returned water sequentially passes through an air preheater to exchange heat with cold air, enters a high-temperature end of an absorbing type heat pump to be heated, enters a second dividing wall type heat exchanger to exchange heat with high-temperature smoke, and finally enters a boiler to be heatedagain; the heated cold air is led into the boiler to provide the oxygen; low-temperature smoke obtained after high-temperature smoke cooling enters a spraying tower to be subjected to spraying cooling, and the cooled smoke is discharged; spraying liquid is neutralized and is pumped into a first dividing wall type heat exchanger to heat secondary net returned water, condensed spraying liquid entersthe absorbing type heat pump to be subjected to heat recycling again, heat is transmitted to the primary net returned water, the spraying liquid cooled again is conveyed to a spraying layer of the spraying tower, and smoke spraying and cooling are achieved; the temperature of smoke can be reduced to below 30 DEG C, and the gas boiler efficiency can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of industrial boilers and energy saving, and relates to a deep waste heat recovery method of boiler flue gas, in particular to a method based on a direct-fired absorption heat pump, a direct contact heat exchanger, an air preheater and a partition heat exchanger advanced boiler flue gas deep waste heat recovery technology. Background technique [0002] The information disclosed in this background section is only intended to increase the understanding of the general background of the present invention, and is not necessarily taken as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. [0003] With the implementation of clean heating in the northern region, gas boiler heating has become an important way of heating. According to the clean heating plan, from 2017 to 2021 in the "2+26" cities, a total of 1.8 billion square meters ...

AI Technical Summary

Problems solved by technology

Absorption heat pump technology can lower the flue gas temperature below 30°C, but the investment is relatively large, and the investment of recovering 1MW of heat is about 1.2 million; heat exchanger technology, the flue gas temperature is limited by the temperature of the cold source, and it is generally difficult to drop below 50°C , and the flue gas condenses to a certain temperature and will condense, producing acidic condensed water, which will cause serious corrosion to the heat exchanger, so it is necessary to use an anti-corrosion heat exchanger, whether it is 316L or modified material, the cost Very high, and it is difficult to guarantee no corrosion at all

Images