Rectification-heat exchange coupled type tray and wet flue gas desulfurization tower

Abstract

The invention belongs to the field of coal-fired flue gas treatment, and discloses a rectification-heat exchange coupled type tray and a wet flue gas desulfurization tower. The tray comprise an upper-layer heat exchange tube bundle, a spray liquid isolation plate, a gas distribution plate and a lower-layer heat exchange tube bundle which are fixedly connected in sequence from top to bottom; the upper-layer heat exchange tube bundle and the lower-layer heat exchange tube bundle are arranged in a cross shape; the spraying liquid isolation plate is located on the gas distribution plate; the spraying liquid isolation plate and the upper-layer heat exchange tube bundle are arranged in a cross shape; the spraying liquid isolation plate and the upper-layer heat exchange tube bundle divide the gasdistribution plate into a plurality of bubbling areas; a plurality of gas flow channel holes are formed in the bubbling areas. With the rectification-heat exchange coupled type tray and the wet fluegas desulfurization tower of the invention adopted, the problem that heavy metal pollutants and SO3 in coal-fired flue gas cannot be efficiently removed in a conventional wet flue gas desulfurizationtower at present can be solved. The tray and tower have the advantages of being remarkable in strengthening effect, simple in structure, low in cost, safe, reliable, free of other negative effects andthe like.

Description

technical field [0001] The invention belongs to the field of coal-fired flue gas treatment, and more specifically relates to a rectification-heat exchange coupled tray and a wet flue gas desulfurization tower. Background technique [0002] With the sharp increase in energy demand and consumption, coal power generation plays an important role. However, coal-fired power generation also brings a series of ecological and environmental problems, which must be properly resolved. Currently, conventional pollutants such as SO 2 , NO x The treatment of some trace unconventional pollutants (such as heavy metals, SO 3 ) has attracted increasing attention from all walks of life. Although heavy metals (arsenic, selenium, lead, etc.), SO 3 The absolute content of pollutants is low, but they are easy to accumulate in organisms, which will cause irreversible damage to the nervous system and reproductive system, and will also cause damage to the ecological environment of water bodies. SO...

AI Technical Summary

Problems solved by technology

Based on these two characteristics, the wet flue gas desulfurization tower in the existing conventional flue gas purification equipment is considered to be the most effective in removing heavy metals and SO 3 potential, however, the current wet FGD for heavy metals and SO 3 The removal effect is not good, and it fluctuates greatly with the combustion conditions and unit configuration. Therefore, the strengthening of wet flue gas desulfurization towers for heavy metals and SO 3 The control effect needs to be solved urgently

[0004] Among the existing technologies on the emission control of heavy metal pollutants in coal-fired flue gas, mainly include: (1) Patent CN108939875A discloses a device for collaborative removal of heavy metals in coal-fired power plants, including heavy metal removal devices arranged in sequence along the flue gas flow direction device, denitrification reactor, phase change agglomeration device, dust removal device, and desulfurization absorption tower, the heavy metal removal device is composed of lead removal device, primary oxidation conversion device, secondary oxidation conversion conversion device, absorption device, Composed of a mercury removal device, after two-stage oxidation and a coordinated absorption device, the arsenic and selenium in the flue gas are removed in a high-valence state by oxidation. This method can achieve a removal effect of 80%-99.5% for heavy metals, realizing Heavy metal synergistic removal of coal-fired flue gas, but the process is complicated, the transformation cost is high, and it is not suitable for large-scale application; (2) Patent CN109045963A discloses an oxidation-absorption removal of gaseous selenium dioxide in coal-fired flue gas In the method, the prepared oxidant and absorbent are sprayed from the upper part of the spray tower at the same time, and form a convection flow with the coal-fired flue gas introduced from the lower part of the spray absorption tower, so that the gaseous selenium dioxide in the flue gas can fully react and realize the selenium dioxide to Selenate conversion and absorption

The highest oxidation efficiency of this method can reach 99%, and the absorption efficiency can reach more than 98%, but this method needs to consume a large amount of chemical reagents, the cost is high, and it will change the composition of the desulfurization slurry and affect the operation of the desulfurization equipment; (3) Patent CN204601981U discloses a A desulfurization tower equipped with multi-layer pallets, the desulfurization tower includes a tower body, and the tower body is provided with a slurry pool, a multi-layer spray layer and a multi-layer demister in sequence from bottom to top, and the tower body is also provided with multi-layer trays , the tray is located above the original smoke inlet and below the uppermost spray layer, and a plurality of through holes are opened on the tray. This method can effectively improve the uniformity of smoke distribution and increase the dissolution rate of limestone, thereby Improve the desulfurization dust removal and mist removal capabilities of the desulfurization tower, but this method is harmful to heavy metals and SO 3 Pollutants have no significant strengthening effect

[0005] The research found that the heavy metals and SO in the existing coal-fired flue gas 3 In the pollutant discharge control technology, there are mainly the following problems: (1) The process flow is complicated and the cost is high; (2) A large amount of chemical reagents are consumed; (3) It has a negative effect on the normal operation of other equipment and affects the normal production and operation process

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