Dry-method flue gas purification method and dry-method flue gas purification device of simultaneously desulfurizing, denitrating and removing mercury

Abstract

The invention discloses a dry-method flue gas purification method of simultaneously desulfurizing, denitrating and removing mercury, and belongs to the field of atmospheric pollution purification technologies. The dry-method flue gas purification method comprises the following steps of firstly, absorbing and removing SO2 in flue gas; secondly, carrying out catalytic oxidation on Hg<0> to obtain HgO by utilizing trace O2 in the flue gas and complementary air, absorbing on the surface of a catalyst, and meanwhile, spraying NH3 and converting NOx to N2 to discharge; lastly, causing commercially available active carbon, which has saturated absorption in the two processes, to enter into a recycling device, generating gases such as CO, H2 and H2S under the conditions that steam is introduced and the temperature is at 1000-1100 DEG C, causing the gases to enter into a wet oxidation process desulfurizing tower (ADA) method operating unit to recycle elemental sulfur, taking the CO and the H2 as fuel gas and returning to a boiler. The process belongs to a tower type fixed bed dry-method united purification process, and the process is simple and convenient for operation and can continuously run.

Description

technical field [0001] The invention relates to a simultaneous desulfurization, denitration and demercuration dry flue gas purification method and device, and the flue gas purification technology is applied to the technical field of air pollution purification. Background technique [0002] Coal is the main energy source in my country, accounting for 75% of the primary energy, 84% of which is used by combustion, and the SO produced by coal combustion 2 , NO X And heavy metal pollutants such as Hg have become the main source of air pollution. At the same time, the lack of sulfur resources restricts my country's industrial development. More than 60% of my country's sulfur resources are pyrite, and pyrite acid used to reach 77%. Now it has dropped to It is less than 40%. After 2010, it has to import a large amount of international sulfur or sulfuric acid to make up for the shortage of production. Therefore, if the SO in the flue gas can be recovered 2 , used to make acid or ele...

AI Technical Summary

Problems solved by technology

[0005] As far as coal-fired industrial boiler flue gas combined desulfurization, denitrification and mercury removal technology is concerned, most of the current combined desulfurization, denitrification and mercury removal technologies are combined staged removal processes in series. The main technical means are: bag filter (mercury removal) + NH 3 Selective catalytic reduction (denitrification) + wet desulfurization device (desulfurization), selective catalytic reduction (denitrification) + circulating fluidized bed (desulfurization) + bag dust removal (mercury removal), the removal effect of these two methods for Hg is With the difference of fuel coal quality and flue gas conditions, the effect varies greatly. The purification device used in this method mainly adopts fixed bed and moving bed. In the traditional fixed bed process, the active coke material is easy to reach saturation and requires frequent regeneration. Moreover, the regeneration loss is large and the operating cost is high; the fluidized bed process is easy to operate, but it has high requirements for the mechanical properties and comprehensive purification capacity of the purification material, the process operation requires high requirements, the amount of active coke is large, the regeneration problem is prominent, and the purification cost Higher, prone to secondary pollution

[0006] The Chinese invention patent with the publication number CN1923337A introduces a method of using ozone as an oxidant to simultaneously oxidize SO 2 , NO and Hg 0 , and then use the lye scrubber to simultaneously desulfurize, denitrify and demercurize, this method does not solve the absorbed Hg 2+ The reduction problem in the scrubber, and the actual mercury removal efficiency is not high, while using ozone to remove SO 2 Oxidation to SO 3 Not good for SO 2 removal of

[0007] The Chinese invention patent with the publication number CN1962034A introduces a method and device for simultaneous desulfurization, denitrification and mercury removal of boiler flue gas. active absorbent for SO 2 The removal rate is above 90%, the removal rate of NOx is above 60%, and the removal rate of Hg is above 50%. The process design is compact, the operation is stable, and there is no waste water discharge. Therefore, it is of great practical significance to develop a simultaneous desulfurization, denitrification and demercuration dry flue gas purification and resource recovery process.

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