Heat exchanger and heat exchanging method

Abstract

The invention discloses a heat exchanger and a heat exchanging method. The heat exchanger comprises a heat absorber, a radiator, a circulating system and a temperature control system. A heat transferpipe of the heat absorber communicates with a heat transfer pipe of the radiator, and external spaces of the heat absorber and the radiator serve as channels of high-temperature tail gas and low-temperature inlet air of a boiler correspondingly. The circulating system is connected to an inlet of the heat transfer pipe of the heat absorber and an outlet of the heat transfer pipe of the radiator, and after a heat exchanging medium is driven to absorb heat of the high-temperature tail gas of the external space of the heat transfer pipe of the heat absorber in the heat absorber, the heat exchanging medium enters the radiator to conduct heat exchanging with the low-temperature inlet air of the external space of the heat transfer pipe of the radiator. The flow rate or the flow velocity of the heat exchanging medium is automatically adjusted through the temperature control system according to the temperature of the boiler tail gas at an outlet of the heat exchanger. According to the heat exchanger, the heat exchanging capacity of the heat exchanger is adjusted through control over the flow rate of the heat exchanging medium, thus temperature control over the boiler tail gas is achieved, and recovered heat can further return into the boiler again by heating boiler feed water or inlet air.

Description

technical field [0001] The invention relates to the technical field of heat exchange, in particular to a heat exchanger and a heat exchange method. Background technique [0002] For biomass boilers, it is necessary to solve the problem of controlling the emission of smoke and dust, and how to improve the efficiency of heat recovery. Although there are many types of heat exchangers on the market, there is a lack of a high-efficiency heat exchanger that can well adapt to the combustion characteristics of biomass boilers. The reasons are as follows: [0003] 1) The dust content in the tail gas of biomass boilers is much higher than that of coal-fired, oil-fired or natural gas boilers, and its dust particles are finer, lighter in weight, with large fluctuations in conductivity and high carbon content. Commonly used water film dust removal or electric dust removal It is difficult to ensure that the exhaust emission meets the new environmental protection requirements, so a bag fi...

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Problems solved by technology

[0003] 1) The dust content in the tail gas of biomass boilers is much higher than that of coal-fired, oil-fired or natural gas boilers, and its dust particles are finer, lighter in weight, with large fluctuations in conductivity and high carbon content. Commonly used water film dust removal or electric dust removal It is difficult to ensure that its exhaust emissions meet the new environmental protection requirements, so bag dust collectors are usually used

[0004] 2) To ensure the long-term safe operation of the bag filter, the temperature of the flue gas must be well controlled to prevent shortening the service life of the bag, increasing the cost of use, and even causing the bag to catch fire

[0005] 3) The furnace firepower of biomass boilers (especially those using untreated biomass waste or garbage) fluctuates greatly, resulting in large changes in the exhaust gas temperature of biomass boilers. Usually, the exhaust gas temperature is above 200 °C, and the load When it is large, it can even reach 300°C, and when the load is heavy, the exhaust gas will also entrain a large amount of sparks, which seriously threatens the safety of the bag

Although these heat exchangers have high heat exchange efficiency, it is difficult to meet the above requirements due to design ideas and structural limitations.

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