Method for removing NO and SO2 from environment pollution emissions

Abstract

The invention provides a method for removing NO and SO2 from environment pollution emissions, which belongs to the field of electrochemistry technology and environment protection technology, in particular to an electrochemical method for simultaneous desulfurization and denitration without secondary pollution. The invention discloses the novel wet type electrochemical method, which has the advantages of simple operation, low cost, environment protection, capability of continuous operation at a higher removal efficiency and capability of singly or simultaneously realizing the desulfurization and the denitration. The invention is characterized in that firstly, carrying out electrolysis in a water-phase electrolyte to generate ferrous iron ions and compounds thereof to realize the effect of absorbing NO and SO2 from a gas phase to a liquid phase; and then, respectively reducing the NO into NH<4+> and N2 and oxidizing the SO2 into SO4<2-> through the electrochemical oxidation-reduction characteristics. The novel electrochemical desulfurization and denitration method can realize the removal of waste gas of single NO or SO2, can also be used for simultaneous desulfurization and denitration, has small influence by O2 and acidic gas such as HCL and the like in smoke gas, and has no emission of waste water or other secondary pollutants. The desulfurization efficiency and the denitration efficiency respectively reach more than 80 percent and more than 98 percent, and the continuous operation can be realized.

Description

technical field [0001] The invention belongs to the field of electrochemical technology and the field of environmental protection technology, and specifically relates to a separate or simultaneous desulfurization and denitrification method without secondary pollutants. The invention uses wet electrochemical removal of environmental pollution emissions NO and SO 2 Methods. The present invention produces Fe by electrolysis 2+ and its compounds absorb NO, realize NO and SO through electrochemical redox 2 Selective transformation; suitable for producing NO, SO 2 The desulfurization and denitrification of fixed pollution sources of tail gas, such as power plants, factories, petroleum and chemical enterprises such as nitric acid plants, which use coal, petroleum and natural energy as energy sources, have broad practical application value and prospects. technical background [0002] Combustion of fossil energy fuels such as coal, oil and natural gas produces SO 2 , NO, are the ...

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Problems solved by technology

However, this process shows many insurmountable difficulties in the process of operation, especially for developing countries like my country that use coal as the main energy source: (1) my country basically still uses traditional wet limestone washing alone In the desulfurization stage, in addition to the large investment, the main problem is that a large amount of desulfurization products are difficult to dispose of

(2) The method of solid-phase catalytic reduction requires the use of a large amount of ammonia and heavy metal catalysts, and there are problems such as ammonia leakage, temperature control, and disposal after catalyst poisoning and failure

(3) Water vapor and unremoved SO in wet desulfurization method 2 , solid particles, etc. will have a great negative impact on catalytic reduction denitrification; wet limestone-NH 3 The catalytic reduction and desulfurization and denitrification process still has problems such as large area occupation, complicated process operation, large investment and high operating costs; this greatly limits the popularization and application of this process, especially in developing countries.

However, the relevant electrochemical methods reported in the prior art usually require an external power source and a relatively complicated electrolysis device (Raju, T.; Chung, S.J.; Moon, I.S. Novel process for simultaneous removal of NOx and SO 2 from simulated flue gas by using a sustainable Ag(I) / Ag(II) redox mediator.Environ.Sci.Technol.2008, 42, 7464-7469), which undoubtedly increases the difficulty of large-scale promotion and application

In addition, a large amount of oxygen in the flue gas consumes a large amount of current, so that its current efficiency is greatly limited (Song, H.-S.; Moon, J.; Hwang, H.J. Electrochemical decomposition of NO over composite electrodes on YSZ electrolyte. J. Eur. Ceram. Soc. 2006, 26, 981-986)

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