Tail gas recycling device for transforming hot air grain dryer

Abstract

The invention discloses a tail gas recycling device for transforming a hot air grain dryer. A tail gas recycling system is formed by a tail gas recycling cover, a dust collecting hopper, a tail gas recycling pipeline, an axial flow fan and a purified tail gas cover. A tail gas purifying system is formed by a gravity dust settling chamber, a scraper purifier, a dust removing fan and an air supply tail gas pipeline. A cold air preheating system is formed by converting the third set of heat exchangers of an original hot air grain dryer into an air preheater. A flue gas recycling system is formedby a first flue gas pipeline, a flue gas adjusting valve, a second flue gas pipeline, a flue gas check valve, a cold air pipeline, a cold air adjusting valve and a mixed flue gas pipeline. The tail gas recycling device has the advantages of reducing the drying cost, ensuring the grain drying yield, improving the drying efficiency, reducing the pollution and the like.

Description

technical field [0001] The invention relates to the technical field of grain drying machinery and equipment, and more specifically, the invention relates to a tail gas recovery and reuse device used to transform a hot air grain dryer. Background technique [0002] At present, the hot air grain dryers produced in China do not have tail gas for recycling and are directly discharged into the outdoor atmosphere, resulting in the waste of more than 30% of the heat produced by the original coal-fired hot air stove. In accordance with the spirit of the relevant national, provincial and municipal documents, small-tonnage coal-fired boilers (kilns) have been phased out. It is recommended to use clean energy such as biomass, natural gas, electricity, and air source heat pumps to replace coal. [0003] There are two ways to transform coal-fired hot blast stoves into biomass straw hot blast stoves: one is evolved from ordinary chain hot blast stoves, but the furnace arch is increased an...

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Problems solved by technology

[0003] There are two ways to transform coal-fired hot blast stoves into biomass straw hot blast stoves: one is evolved from ordinary chain hot blast stoves, but the furnace arch is increased and the secondary blast is increased, due to the burning speed of biomass particles It is necessary to replace the original feed hopper and add spraying. On the one hand, this transformation method is not energy-saving, and on the other hand, the emission is difficult to meet the standard; another transformation method is John’s energy-saving high-temperature gasification transformation method. The combustion system of the boiler is completely dismantled and replaced with an inclined fixed grate. The hydraulic feeding is controlled by a computer to make the operation of the boiler easier and more complete. However, the problems faced are the same as the previous transformation method.

[0004] Generally speaking, simply transforming the original coal-fired grate into biomass straw granules and briquette hot blast stoves still has the following disadvantages: First, due to the high moisture content of biomass straw bales, it cannot be really applied to grain drying at present. In dry production; secondly, the use of biomass straw granules and briquette hot air stoves to replace coal-fired hot air stoves has not been accepted and recognized by the majority of users because the grain drying cost is 30% higher than that of coal-fired hot air stoves; 3. Renovate the biomass straw granule and briquette hot blast stove in the original coal-fired hot blast stove grate. Because the output of the biomass straw hot blast stove is lower than that of the coal-fired hot blast stove, it cannot meet the designed output of the original hot blast grain dryer; Fourth, even if some of the exhaust gas of the dryer is recovered, it is not purified, so the grain bran in the exhaust gas enters the heat exchanger and is heated and burned to produce 2, 3-benzene, propylene and other carcinogenic substances that pollute the grain, or the grain bran May block heat exchanger causing fire

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