Chemical reaction system of electrochemical cell type, method for activation thereof and method for reaction

Abstract

The present invention relates to a chemical reaction system for efficiently excluding nitrogen oxides with low power consumption when excess oxygen is present in exhaust gas, to a method of use therefor, to an activation method therefor, and to a reaction method for oxidizing or reducing by the use of an oxidation-reduction reactor with high selectivity without the need to supply or exchange a reducing agent or oxidizing agent.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrochemical cell-type chemical reaction system, and more specifically relates to a chemical reaction system which efficiently excludes nitrogen oxides from exhaust gas containing oxygen. The present invention is useful in that it provides a novel chemical reactor which has micro reaction regions for performing oxidation and reduction reactions on a target substance introduced into part of the chemical reaction part of the aforementioned chemical reaction system so that oxygen and nitrogen oxides are separated and adsorbed from exhaust gas by particular structures within the aforementioned micro reaction regions, thus allowing a target substance to be efficiently processed with low electric power consumption. [0002] Moreover, the present invention relates to an energy-saving electrochemical reaction system and an activation method therefor, and relates more particularly to a chemical reaction system which efficiently excl...

AI Technical Summary

Benefits of technology

[0016] That is, it is an object of the first embodiment of the present invention to solve the aforementioned problems of background art and provide a chemical reactor capable of efficiently excluding nitrogen oxides with low power consumption wherein the amount of current required to break down nitrogen oxides is reduced by using pairs of adsorbent substances which are selective for oxygen molecules and nitrogen oxide molecules to facilitate absorption of nitrogen oxides when excess oxygen is present in exhaust gas.

[0054] In the present invention, it is possible to apply current or the like only when the performance of the chemical reaction system has declined in order to ionize and remove by pumping oxygen adsorbed by the oxygen deficient part of the chemical reaction part. Moreover, it is possible to simultaneously reenergize the reduction phase. In this way, the amount of current in the present invention can be much less than the amount of current required for oxygen pumping in conventional electrochemical cell systems.

Problems solved by technology

However, because the exhaust gas from lean burning engines and diesel engines, which allow improved fuel consumption, contains an excess of oxygen, reduction of catalytic activity due to adsorption of oxygen by the surface of the ternary catalyst is a problem, preventing exclusion of nitrogen oxides.

However, the problem is that in the aforementioned method if there is an excess of oxygen in the exhaust gas, because the adsorption and decomposition reaction sites of the coexisting oxygen and nitrogen oxides consist of the same oxygen defects, the adsorption probability of the nitrogen oxides is much lower than that of the oxygen molecules for reasons of both molecular selectivity and coexisting molecular ratios, so that a large flow of current is required to break down the nitrogen oxides, greatly increasing electric power consumption.

However, because in this method residual oxygen molecules in the treated gas which have passed through the upper part of the same layer are still more selectively adsorbed and degraded in the reaction sites than are the nitrogen oxides, the reduction in energy consumption is inadequate.

Moreover, another problem with this method is that the reduction in energy consumption is inadequate because current needs to be supplied continuously in order to remove coexisting oxygen molecules.

Porous membranes which allow selective permeation of molecules include zeolites and other having nanopores, but synthesis of dense zeolite membranes without pinholes has not been established.

However, in a reaction method using a reaction separation membrane in which an ion conductor membrane is provided with electrodes and voltage is applied between the electrodes with the field gradient as the drive force, oxidation and reduction ability is high but selectivity is low.

For example, when removing nitrogen oxides by reduction in a reactor in which the aforementioned ion conductor is provided with electrodes, if oxygen molecules are present they are also broken down into oxygen ions, reducing the efficiency of the reduction removal of nitrogen oxides which is the objective of exhaust gas purification.

Moreover, while a simple oxidation-reduction reaction using a reducing agent or oxidizing agent with suitable selectivity is also possible, in this case the reducing agent or oxidizing agent needs to be supplied or replaced because the reaction cannot continue once this has been exhausted.

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