Integrated equipment and method for desulfurization and denitrification synergistic absorption

Abstract

The invention relates to integrated process and equipment for desulfurization and denitrification synergistic absorption. The process relates to the concentrations and specific proportions of nitric oxide and sulfur dioxide in waste gas, an absorbent and the like. The equipment comprises a feeding device, an auxiliary reaction device, an absorption device and a gas-liquid separation device, wherein the feeding device is communicated with the reaction device and the absorption device, and the absorption device is communicated with the gas-liquid separation device; the reaction device is mainlyused for generating nitrogen dioxide and includes, but not limited to nitrogen dioxide generated by arc discharge, so that nitrogen monoxide in the waste gas is oxidized to generate nitrogen dioxide;the absorption device is an absorption tower or a micro-reactor, preferably a micro-reactor, and more preferably a micro-dispersion type reactor; in the reaction device, waste gas under specific process conditions and an absorbent are mixed and react to be absorbed and removed. The process and the equipment for synergistically absorbing nitrogen oxide and sulfide have the advantages of simple process, high absorption efficiency, no need of introducing other substances such as a catalyst into a reaction system, capability of realizing resource utilization of waste gas and the like.

Description

technical field [0001] The invention belongs to the technical field of flue gas treatment, and relates to an integrated equipment and method for synergistic absorption of desulfurization and denitrification. Background technique [0002] In recent years, with the increasingly serious pollution of nitrogen oxides and sulfide emissions, the national environmental protection department has higher and higher environmental protection requirements for industrial flue gas emissions. The national "Coking Chemical Industry Pollutant Emission Standards" stipulates that from January 1, 2015, existing enterprises and newly established enterprises in ordinary areas shall implement NO emission in coke oven flue gas. x ≤500mg / m 3 , SO 2 ≤50mg / m 3 . Coal-fired coke oven projects in key control areas implement special emission limits for air pollutants, that is, require NO in coke oven flue gas x ≤150mg / m 3 , SO 2 ≤30mg / m 3 ; Some passage cities have begun to implement ultra-low emis...

AI Technical Summary

Problems solved by technology

Combined desulfurization and denitrification technology refers to an integrated technology formed by integrating separate desulfurization technology and denitrification technology, such as the traditional combined "selective catalytic reduction denitrification (SCR) + limestone / gypsum wet flue gas desulfurization (WFGD)" Although the technology has high desulfurization and denitrification efficiency, the system is complex, occupies a large area, and the investment and operation costs are high. SO in flue gas 2 The technology that eliminates NOx at the same time, this type of technology has the characteristics of compact structure and low operating cost, but due to equipment limitations, it is often difficult to discharge the flue gas after treatment up to the standard

[0006] CN110201512A discloses a method for simultaneous desulfurization and denitrification using red mud. First, the flue gas to be treated is mixed with the slurry obtained by mixing part of the red mud and water for the first desulfurization and denitrification. After the red mud is mixed, it is mixed with the ozone-oxidized flue gas for the second desulfurization and denitrification treatment. The total desulfurization efficiency is as high as 95%, and the total denitrification efficiency reaches 60-80%. However, the process is complicated and the red mud needs to be ball milled. Such as pre-treatment, the required settling process takes 6-10 hours, and a larger settling tank is required under continuous treatment conditions to meet the requirements. At the same time, this process fails to realize the resource recovery of nitrogen and sulfur elements

[0007] CN110052139A provides a flue gas desulfurization and denitrification device and method, the flue gas desulfurization and denitrification device includes an ozone generating unit, a desulfurization and denitrification unit and a flue gas post-processing unit connected in sequence, SO 2 The removal rate is as high as 99.2%, NO x The removal rate is as high as 93.9%; however, the desulfurization and denitrification unit of the device includes 2-4 desulfurization and denitrification towers connected in series, each desulfurization and denitrification tower includes 2-6 spray layers, and each spray layer is controlled by an independent circulation pump The flow of spray liquid, the process is more complicated, and the equipment occupies a large area. At the same time, the spray liquid is composed of water, absorbent and absorption aid. The processed product contains various substances, and post-processing is difficult.

In the existing denitrification process, NO is not easy to absorb, and needs to be further oxidized into NO 2 or N x o y ; but even after oxidation, alkaline absorbents such as ammonia and caustic soda solutions of different concentrations x o y The absorption is not ideal, which is the main reason why the current absorption tower is relatively high and the equipment is complicated

In previous studies, it was found that NO 2 and SO 2 Promote each other in the process of lye absorption, but there is little research on the process

[0010] On the other hand, the existing desulfurization and denitrification devices were built according to the environmental protection requirements at that time. With the upgrading of environmental protection requirements, especially the implementation of ultra-low emission standards, some existing devices and processes can no longer meet the new environmental protection regulations.

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