Coal-fired boiler flue gas environmentally-friendly deep treatment method and apparatus

Abstract

The present invention provides a coal-fired boiler flue gas environmentally-friendly deep treatment method, dedusting, desulfurization and denitration deep treatment is performed on coal-fired boiler flue gas by a combined Venturi water film dedusting desulfurization and ammonia escape treatment technique, spray atomization mixing, venturi mixing, high-speed cyclone separation and water film absorption are combined, high salt wastewater comprising calcium ions and magnesium ions is used as a cleaning agent, after treatment with an oxidation sedimentation tank, a desulfurization agent is supplemented, and pH value is adjusted; and the treated coal-fired boiler flue gas is pumped back to a venturi pressure sprayer and a granite water film dust remover to form water film circular treatment; and after the treatment, boiler flue gas particulate matter emissions and sulfur dioxide emissions can be effectively reduced, the amount of used ammonia is reduced, and the liquid to gas ratio of the delivery amount of the cleaning agent can be reduced.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and in particular relates to a method for environmentally friendly deep treatment of flue gas from a coal-fired boiler and a device for environmentally friendly deep treatment of flue gas from a coal-fired boiler. Background technique [0002] Environmental protection treatment of flue gas from coal-fired boilers is about soot, sulfur dioxide, and nitrogen oxides (in NO 2 The effective governance of the project is in line with the technical management of the country's maximum allowable emission concentration. [0003] The emission limits of pollutants allowed in the "Emission Standards of Air Pollutants for Thermal Power Plants" (GB13223-2011) are as follows; Among them, from July 1, 2015, existing thermal power boilers and gas turbines must implement the new regulations for smoke, sulfur dioxide , nitrogen oxide emission limits; [0004] The maximum allowable emission concentr...

AI Technical Summary

Problems solved by technology

[0031] 1) The existing mainstream technology for flue gas treatment of coal-fired boilers requires large investment in dust removal, desulfurization, and denitrification equipment, high operating costs, and secondary pollution

[0032] 2) Problems such as the aging and leakage of the bag dust removal in the prior art make the particulate matter in the outlet flue gas sometimes exceed the standard, and cannot stably meet the national limit standard; at the same time, the shutdown of the bag due to leakage of the bag has a huge impact on production, and the cost of replacing the bag is too high; in addition, the Yinchuan area The smoke and dust emission standard is 20mg / m3, and the technical standard has been improved

[0033] 3) Sulfur dioxide emission standards require burning high-quality coal and using a large amount of desulfurizers to meet the national environmental protection standards. The emission value is ≤200mg / m3, which requires high coal combustion, large waste of resources, and high operating costs.

[0034] 4) The SNCR process needs to consume ammonia water. Although it can meet the emission requirements of the existing environmental protection regulations (≤200mg / m3), the operating cost is relatively high. After the denitrification is put into operation, the air preheater in the low-temperature section at the tail is easy to block because of escape after the reaction The ammonia water will generate ammonia bisulfate liquid on the heating surface of the tail, which is easy to adhere to the wall of the air preheater, and solid dirt will block the passage between the pipes when it encounters dust, corrode the air preheater of the steel pipe, and cause secondary pollution of the atmosphere at the same time; research on low nitrogen Combustion denitrification deep treatment technology is of great significance

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