Method for removing nitric oxides by absorption and plasma selective catalytic reduction

Abstract

The invention relates to treatment of nitric oxides in waste gases and aims to provide a method for removing nitric oxides by absorption and plasma selective catalytic reduction. The method comprises: (1) passing the waste gases containing the nitric oxides through a plasma reactor filled with an absorption catalyst to make the nitric oxides absorbed onto the absorption catalyst; and (2) stoppingcharging waste gases, passing a mixed gas of oxygen and a reducing gas through the plasma reactor, and performing a plasma discharge reaction. The absorbed nitric oxides are desorbed and catalytically reduced into nitrogen under the common action of plasma and the absorption catalyst. In the invention, the whole nitric oxide removal process is accomplished on one device; the method can be widely used for removing nitric oxides from industrial tail gases, flue gases and automobile tail gases; the absorbent is low in cost and easy to recycle; the plasma reaction has low requirements on device and reaction conditions; the energy consumption in the whole process is low; and the conversion rate I the reduction of the nitric oxides into N2 reaches over 90 percent.

Description

Technical field [0001] The invention relates to nitrogen oxides (NO x ), especially involving the combination of adsorption and low-temperature plasma selective catalytic reduction processes to remove nitrogen oxides and reduce them to N 2 Methods. Background technique [0002] Nitrogen oxide is an important air pollutant gas, and it is one of the important factors in the formation of acid rain and photochemical pollution. It severely damages the health of the earth's ecological system. At the same time, it is toxic to humans and endangers human health. At present, the removal of nitrogen oxides can generally be divided into two categories: non-catalytic method and catalytic method. Non-catalytic methods mainly include solid absorption and liquid absorption. For example, molecular sieves, activated carbon and silica gel are common solid adsorbents, while acid and lye are common liquid adsorbents. Catalytic methods are mainly catalytic reduction method and catalytic decomposition...

AI Technical Summary

Problems solved by technology

But in general, the methods developed so far are not satisfactory, such as limited scope of application, high requirements on reaction conditions, complex equipment, cumbersome process, nitrogen oxide removal rate and energy efficiency of the reaction process still need to be improved, etc.