Flue gas pollutant cooperation removal technology based on electrolysis

Abstract

The invention discloses a flue gas pollutant cooperation removal technology based on electrolysis. The problems are solved that technologies are complex, the pollutant treatment efficiency is low, investment and operation cost are high in present flue gas treatment. The technology comprises steps: flue gas is pressurized and sent to a concentration tower, a reaction is carried out, the flue gas going out from the concentration tower is sent to an absorbing tower and contacts and reacts with a circulating absorption solution sprayed from a spray layer at the upper part of the tower in a reverse manner, and the flue gas after reaction is discharged from the top of the absorbing tower; part of the concentrate at the tower bottom of the concentration tower is subjected to iron removal, then is sent to a ammonium sulfate crystallization system, the flue gas goes into the absorbing tower from a flue gas inlet at the middle part of the absorbing tower, goes through at least one absorbing and electrochemical reaction layer arranged at the upper part of the tower firstly, then contacts and reacts with a circulating absorption solution in a reverse manner, then goes through a filler layer and a spraying layer, and is discharged from a flue gas outlet. The technology is simple, the reaction efficiency is high, the operation and investment cost are low, the system land occupation area is small, and the technology is especially suitable for cooperation treatment of multiple pollutants of sulfur dioxide, nitrogen oxides, fine particles, dioxin and the like.

Description

Technical field [0001] The invention relates to a flue gas treatment process, specifically a flue gas pollutant removal process based on electrolysis, and is particularly suitable for flue gas with multiple pollutants such as sulfur dioxide, nitrogen oxides, fine particles, and dioxins. Collaborative governance. Background technique [0002] There are many types of flue gas desulfurization and denitrification technologies, and the engineering application of individual desulfurization or denitration technologies is becoming more and more perfect. However, the application of multi-pollutant cooperative control technology for flue gas is less. At present, in addition to the more mature adsorption method, other collaborative control technologies for engineering applications, especially the multi-pollutant collaborative control technology of flue gas wet method, have not been reported. Wet flue gas synchronous desulfurization and denitrification technology, such as wet ammonia-compl...

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Problems solved by technology

[0004] On the one hand, there are following problems in adopting the iron filings method in the regeneration step: (1) Since the absorption liquid is acidic, the iron filings are easily corroded, resulting in a large consumption of iron filings, and the concentration of iron ions in the absorption liquid is too high, which increases the efficiency of iron removal. The cost also affects the quality of desulfurization and denitrification by-products; (2) Since the elemental iron in the iron filings is oxidized and corroded into the solution, the pH value of the absorption solution increases, resulting in the weakening of the regenerative reduction ability of the iron filings to the complexing agent

In order to ensure the denitrification efficiency, acid needs to be added to the system, resulting in a further increase in denitrification costs

(3) The consumption of iron filings is relatively large, and a large amount of elemental iron is oxidized into the absorption liquid. Since the pH value of the absorption liquid is controlled above 5.0, the absorption liquid contains a large amount of ferric hydroxide colloid (suspended matter), which will lead to circulation The wear of the impeller of the pump is increased, and it will also cause the nozzle and pipeline to block

(4) Since iron filings are filled in the closed regeneration tower, and the consumption of iron filings is continuous, continuous replenishment of iron filings cannot be realized

[0010] (1) The area where the electrolyte of the existing electrochemical reaction process enters the reactor is the area surrounded by the cathode, the anode, and the shell of the reactor. When leaving the reactor, the electrolyte flows out from the cathode chamber and the anode chamber respectively, and the reactants The conversion rate is low, the highest will not exceed 50%

[0011] (2) For the reaction system with good electrochemical reversibility between the reactant and the product, the existing electrolysis device will cause the repeated conversion between the reactant and the product in the electrolysis reactor, which not only affects the conversion efficiency, but also waste of electricity;

[0012] (3) The existing electrolysis device cannot effectively use the flow of the electrolyte itself to provide a large turbulent force for rapid renewal of the reactants on the electrode surface, and the electrochemical reaction speed is relatively slow, thereby reducing the reaction conversion rate;

[0013] (4) For complex reaction systems containing side reactions, existing electrolysis devices cannot effectively remove electrochemical reaction products that cause side reactions in a timely manner;

[0014] (5) The existing electrolysis device has a complex structure and a large footprint

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