All-condition wet desulphurization exhaust gas dehumidifying and white smoke removing system and method

Abstract

The invention discloses an all-condition wet desulphurization exhaust gas dehumidifying and white smoke removing system and method. The system is characterized by mainly comprising a desulphurizationtower (1), a deposition tank (2), a clean water tank (3), a temperature decrease pump (4), a cooling tower (5), a circulating water tank (6) and a condensing pump (7), wherein a gas inlet (11) and a gas outlet (12) are formed in the desulphurization tower (1); a desulphurization spraying layer (1-1), a demister layer (1-2), a demister flushing layer (1-3), a first gas raising plate (1-4), a first-stage condensing spraying layer (1-5), a second gas raising plate (1-6), a second-stage condensing spraying layer (1-7), a demisting dehumidifying layer (1-8) and a heater layer (1-9) are sequentiallyarranged in the desulphurization tower (1) from the bottom up. Compared with the prior art, the system and the method have the advantages of being low in investment cost and running energy consumption; all-condition, all-reason and all-weather smoke dehumidifying and white smoke removing can be performed based on the environmental temperature and the boiler load change.

Description

technical field [0001] The invention relates to a system and method for collecting water and eliminating white smoke from tail gas of wet desulfurization under full working conditions, belonging to the field of resources and environmental protection. Background technique [0002] The exhaust gas temperature of wet desulfurization tail gas is 50℃~55℃. It is supersaturated wet flue gas. The discharge of a large amount of evaporated water into the environment is the main reason for the large water consumption of the wet desulfurization unit. Under winter climate conditions, the ambient air temperature is low, the density is high, and the atmospheric stability is high. A large amount of moisture emitted from wet desulfurization tail gas is difficult to diffuse in the air, and it is easy to accumulate near the emission source. At the same time, the wet desulfurization tail gas also carries a large amount of unremoved gypsum slurry droplets, dust particles, nitrogen oxides (NO x...

AI Technical Summary

Problems solved by technology

The direct heating method of flue gas and the air mixing method to eliminate white smoke only reduce the emission humidity of the flue gas, and do not have the functions of water resource recovery and pollutant removal in the flue gas, and the amount of heating and air mixing required in the low temperature environment in winter is huge , cannot adapt to the low temperature environment to eliminate white smoke; MGGH flue gas heat exchange method is used to heat up the desulfurized flue gas by heating and cooling the original flue gas to realize the elimination of white smoke in the flue gas, but due to the temperature of the inlet and outlet of the desulfurization device Due to the influence of flue gas temperature, the amount of heat taken is limited, and it is impossible to condense the flue gas deeply. The water saving of the desulfurization system is limited, and it is difficult to eliminate white smoke in the low temperature environment in winter; the direct heating method of flue gas condensation reheating is to condense the desulfurization tail gas first. Recover part of the moisture in the flue gas, and then heat the flue gas to achieve whitening of the flue gas and recover part of the water resources. However, the cold source is greatly affected by the change of environmental climate and boiler operating load, and it cannot be realized under all working conditions. Flue gas collection water elimination white smoke

[0004] Patent CN201810580242.0 discloses a system and method for eliminating white smoke from flue gas. The ambient air is used to perform indirect heat exchange and cooling on the flue gas at the desulfurization outlet. After two stages of heating, the ambient air and the dehydrated condensed flue gas are mixed to realize the elimination of tail gas white smoke. The heat exchange process of this scheme is carried out on the inlet and outlet flues. The ground area, and the mixed air volume is greatly affected by the ambient air humidity, which is difficult to control

Patent CN201710862586.6 discloses a high-efficiency water intake and white smoke collaborative pollutant removal device and working method. The wet flue gas is condensed to collect water on the outlet flue of the desulfurization tower, and the residual heat of the inlet flue gas is recovered for heating and condensation. After the flue gas, the desulfurization tail gas white smoke control is realized. The flue condensation process adopted in this scheme is affected by the high gas velocity of the flue gas, and the temperature drop of the wet flue gas and the amount of water vapor condensation are small. At the same time, it is subject to the influence of the flue gas temperature at the inlet and outlet , the temperature rise of the flue gas at the outlet is limited, and it is difficult to eliminate white smoke in a low-temperature environment in winter

Patent CN201710451922.8 discloses a device and method for desulfurization flue gas ultra-clean dust removal and white smoke elimination. The ambient air cooling circulating coolant is used to cool and condense the flue gas, and the water is recovered to flush the demister to complete the heat exchange of hot air and condensation. After the flue gas is mixed with air to eliminate white smoke, this solution has a high ambient air temperature in summer and limited heat transfer, and the amount of condensed water is not enough to flush the demister. Large, directly used for flushing the demister will cause the water balance of the wet desulfurization system to be destroyed, resulting in the failure of the desulfurization device to operate normally, and if the condensation is small, the mixing air volume will not be enough to eliminate white smoke

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