Concentrated heat supply system for reclaiming smoke afterheat by absorption heat pump

Abstract

The invention belongs to the technical field of energy sources, and relates to a concentrated heat supply system for reclaiming smoke afterheat by an absorption heat pump. The system is used for reclaiming smoke afterheat of natural gas and water. The system is composed of a smoke flue, the absorption heat pump, a spray device, a water quality processing device and a circular water pump; smoke flows in the smoke flue from bottom to top; circular water is ejected by the spray device to form atomized drops for directly contacting with the smoke to exchange heat and is introduced to an evaporator of the absorption heat pump by the water pump after being processed by the water quality processing device after flowing out from the smoke flue; hot net returned water is sequentially introduced toan absorber and a condenser of the absorption heat pump; the circular water absorbing heat of the smoke and the hot net returned water are subjected to heat exchange in the absorption heat pump to reach the needed temperature and then are returned to a hot net. The smoke and the water are in direct contact for heat exchange in the invention; the heat of the circular water heated by the smoke is extracted from the absorption heat pump to raise the temperature of the returned water of the heat supply system; thus the total energy utilization rate of the concentrated heat supply system is increased; and the effects of cleaning the smoke and protecting the environment are achieved.

Description

technical field [0001] The invention belongs to the field of energy technology, and in particular relates to a central heating system which utilizes an absorption heat pump to recover waste heat from flue gas. Background technique [0002] As a clean energy, natural gas is mainly composed of methane, and the product after combustion in a gas boiler or gas turbine is mainly CO 2 and water vapor. Natural gas boiler is an important primary energy utilization equipment. Compared with coal-fired boilers, natural gas boilers have higher thermal energy utilization efficiency, and the pollutant components in flue gas (dust, SO 2 , NO x , TSP and CO) content is lower. However, in general natural gas boilers, the exhaust gas temperature is as high as 200 °C or more. After the gas turbine has done work, the temperature of the flue gas is still around 150°C. If the flue gas is directly discharged into the atmosphere, it will be a huge waste of energy. Therefore, the waste heat reco...

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Problems solved by technology

It is said that this device can make the flue gas rotate and flow, it is easy to manufacture, and the heat exchange efficiency is ideal, but it still belongs to the flue gas-water indirect heat exchange method

[0006] Chinese Patent CN200910238452.2 "Heat Pump Gas Boiler Waste Heat Recovery Unit" proposes a method of using an absorption heat pump to recover waste heat from flue gas to heat the return water of the heating system, but the heat exchange method between flue gas and circulating water is still flue gas-water indirect heat transfer

[0007] For the above-mentioned flue gas-water indirect heat exchange method, the heat transfer coefficient is generally lower than 80w / m 2 °C, so when recovering the waste heat of flue gas with low temperature, a large number of steel pipe heating surfaces need to be arranged, so a large amount of steel is required, and at the same time, it will cause high flow resistance to the flue gas

There are other problems with the indirect heat exchange method: for example, the heat transfer surface is prone to scaling and requires regular maintenance; water treatment methods such as deionized water are required; the heat exchange effect of the heat exchanger deteriorates after long-term operation

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