Method for oxidation of volatile organic compounds contained in gaseous effluents and device thereof
The present invention relates to both a method and a device for removing Volatile Organic Compounds (VOC) from gaseous streams in conduits, chimneys and/or exhaust ducts. The method is especially useful in eliminating a large variety of pollutants, and especially organic odorous pollutants such as mercaptans and sulfurous compounds. The method is based on the principle of direct oxidation of the pollutants by ozone and the conversion of these pollutants into non-harmful products, and comprises the steps of: a) providing an electrical corona discharge reactor capable of producing ozone; b) supplying an electric current to the corona discharge reactor; and c) causing the gaseous effluents to flow through the reactor. With this method, the volatile organic compounds contained in the gaseous effluents are oxidised by the ozone produced by the corona discharge reactor. The present invention also relates to a device for reducing this method into practice, this device being a corona discharge reactor comprising two concentric electrodes producing ozone.
1. A method for the oxidation of volatile organic compounds contained in gaseous effluents, comprising:
a) providing an electrical corona discharge reactor for producing ozone;
b) supplying an electric current to said reactor in order to generate corona discharge;
c) passing the gaseous effluents upstream of the corona discharge reactor through a condenser in order to reduce the amount of water contained in said gaseous effluents and through a filter in order to remove solid particles also contained in said gaseous effluents before said gaseous effluents are passed through said reactor;
d) then passing the gaseous effluents through said corona discharge reactor in order to oxidize the volatile organic compounds contained in the gaseous effluents by the ozone generated in;
e) causing the gaseous effluents also to contact a metal catalyst in order to further oxidize volatile organic compounds contained in said gaseous effluents; and
f) subjecting the gaseous effluents also to UV radiation in order to further oxidize volatile organic compounds contained in said gaseous effluents.
2. The method of claim 1 , wherein the electrical corona discharge reactor comprises at least two spaced apart electrodes between which the gaseous effluents flow.
3. The method of claims 2 , wherein said electrodes are incorporated respectively into two concentric outer and inner cylinders, the outer cylinder forming an outer duct wherein the gaseous effluents flow, the inner cylinder being concentrically positioned inside the outer cylinder and being spaced apart and electrically insulated therefrom.
4. The method of claim 3 , wherein the outer cylinder has an inner surface and an outer surface, a first one of said electrodes being incorporated to the outer surface of the outer cylinder.
5. The method of claim 4 , wherein the outer surface of the outer cylinder is coated with an electrically conductive material and wherein the outer cylinder is made of a dielectric material.
6. The method of claim 4 , wherein said first electrode comprises a plurality of electrically conductive strips extending longitudinally on the outer surface of the outer cylinder, and wherein the outer cylinder is made of a dielectric material.
7. The method of claim 3 , wherein the inner cylinder has an outer surface provided with a plurality of protrusions.
8. The method of claim 3 , wherein the inner cylinder is hollow and forms an inner duct wherein a flow of gas or liquid circulates.
9. The method of claim 8 , comprising the additional step of circulating a flow of gas or of liquid into the inner cylinder to regulate the temperature into the reactor.
10. The method of claim 9 , wherein said flow of gas or of liquid is a flow of a cooling gas or of a cooling liquid thereby reducing the temperature into the reactor.
11. The method of claim 1 , wherein steps e) and f) are carried out simultaneously with step d) within said corona discharge reactor.