A dust and nitrogen integrated flue gas purification device suitable for a biomass boiler

Abstract

The utility model relates to the technical field of biomass boiler, specifically is a dust and nitrate integration flue gas purification device suitable for biomass boiler, its reduces smoke air flue length to reduce heat loss, flue gas pressure and induced draft fan lift, reduces energy consumption as a whole, it includes biomass boiler, desulfurization device, dust and nitrate integration device, induced draft fan and chimney that arrange in proper order, its characterized in that, set up between the dust and nitrate integration device and the induced draft fan there is smoke cooler no.

Description

Technical Field

[0001] This utility model relates to the field of biomass boiler technology, specifically to an integrated dust and nitrogen oxide flue gas purification device suitable for biomass boilers. Background Technology

[0002] Currently, SCR denitrification in biomass boilers is generally implemented after dust removal. Some systems use high-temperature metal filter bags combined with conventional high-temperature SCR denitrification, while others employ desulfurization and dust removal + flue gas heating + medium- and low-temperature SCR denitrification. However, both of these processes have high construction and operating costs. The first process requires high-temperature filter bags and stable operation in a high-temperature environment, while the second process consumes a large amount of steam for flue gas heating and uses low-temperature catalysts, which are expensive. Currently, integrated dust and nitrogen removal flue gas purification devices are appearing on the market, such as... Figure 1 As shown, the main problem with external air preheaters is the long flue gas duct, which leads to large heat loss and high pressure loss. Summary of the Invention

[0003] To address the aforementioned technical problems, this utility model provides an integrated dust and nitrogen oxide flue gas purification device suitable for biomass boilers. It reduces the length of the flue gas duct, thereby reducing heat loss, flue gas pressure, and induced draft fan head, and ultimately lowering energy consumption.

[0004] The technical solution is as follows: an integrated dust and nitrogen oxide flue gas purification device suitable for biomass boilers, comprising a biomass boiler, a desulfurization device, an integrated dust and nitrogen oxide device, an induced draft fan, and a chimney arranged in sequence. The device is characterized in that a first flue gas cooler is installed between the integrated dust and nitrogen oxide device and the induced draft fan, and a second flue gas cooler is installed between the induced draft fan and the chimney. The first and second flue gas coolers, together with a closed-loop circulating water air preheater, form a closed-loop circulating water system via a circulating water pump. The flue gas inlet end of the closed-loop circulating water air preheater is connected to a primary and secondary air fan, and the flue gas outlet end is connected to the primary and secondary air inlets of the biomass boiler.

[0005] By adopting this utility model, the boiler draws out flue gas with a temperature of over 240°C, which enters the desulfurization device and the integrated dust and nitrogen removal device. A flue gas cooler is added at the rear end to recover the waste heat of the flue gas. The flue gas directly enters the chimney for discharge. The original gas-to-air heat exchanger air preheater of the boiler is replaced with a closed-loop circulating water air preheater, which releases the recovered waste heat to the cold air introduced from the primary and secondary fans. The heated air is used for boiler combustion. Although this method increases the number of flue gas coolers, circulating water pumps and related pipelines, it reduces the overall length of the flue gas duct, reduces heat loss in the flue gas duct, reduces flue gas resistance, saves the power consumption of the induced draft fan, and reduces overall energy consumption. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of existing technology; Figure 2This is a schematic diagram of the present invention. Detailed Implementation

[0007] See Figure 2 As shown, an integrated dust and nitrogen oxide flue gas purification device suitable for biomass boilers includes a biomass boiler 1, a desulfurization device 2, an integrated dust and nitrogen oxide device 3, an induced draft fan 4, and a chimney 5 arranged in sequence. A flue gas cooler 6 is installed between the integrated dust and nitrogen oxide device 3 and the induced draft fan 4, and a second flue gas cooler 7 is installed between the induced draft fan 4 and the chimney 5. The first flue gas cooler 6, the second flue gas cooler 7, and the closed-loop circulating water air preheater 8 form a closed-loop circulating water system through a circulating water pump 9. The flue gas inlet end of the closed-loop circulating water air preheater 8 is connected to the primary and secondary air fans 10, and the flue gas outlet end is connected to the primary and secondary air inlets of the biomass boiler 1.

[0008] The flue gas temperature entering the desulfurization unit 2 and the integrated dust and nitrogen oxide unit 3 after the low-temperature economizer in biomass boiler 1 is controlled at around 240℃. This ensures the bag filter can operate normally without being damaged by excessively high flue gas temperatures, and also allows the medium-low temperature catalyst to operate at a higher temperature, resulting in more stable denitrification. After passing through the integrated dust and nitrogen oxide unit 3, the flue gas enters the first flue gas cooler 6 (cooled to around 140℃), the induced draft fan, and the second flue gas cooler 7 (cooled to 90℃), before finally being discharged through the chimney. A closed-loop circulating water system is added to recover waste heat from the flue gas through the first and second flue gas coolers 6 and 7, and then releases the heat to the air introduced into biomass boiler 1 through the closed-loop circulating water air preheater 8 (a heat exchanger that uses high-temperature water to heat the air). The air then enters from the primary and secondary air inlets for combustion in the biomass boiler. This arrangement simplifies the flue system, reduces the induced draft fan head, and although it adds a water circulation system, it reduces overall energy consumption while ensuring emission efficiency.

Claims

1. An integrated dust and nitrogen oxide purification device for biomass boilers, comprising a biomass boiler, a desulfurization unit, an integrated dust and nitrogen oxide purification unit, an induced draft fan, and a chimney arranged in sequence, characterized in that, A first flue gas cooler is installed between the integrated dust and nitrogen oxide device and the induced draft fan, and a second flue gas cooler is installed between the induced draft fan and the chimney. The first and second flue gas coolers and the closed-loop circulating water air preheater form a closed-loop circulating water system through a circulating water pump. The flue gas inlet end of the closed-loop circulating water air preheater is connected to the primary and secondary air fans, and the flue gas outlet end is connected to the primary and secondary air inlets of the biomass boiler.

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