Method and system of destruction of volatile compounds in wastewater

• US 7,722,775 B2
• Filed: 11/07/2008
• Issued: 05/25/2010
• Est. Priority Date: 03/07/2005
• Status: Active Grant

• Current Assignee: Elcon Recycling Center (2003) Ltd.
• Original Assignee: Elcon Recycling Center (2003) Ltd.
• Inventors: Levin, Alexander
• Primary Examiner(s): Griffin; Walter D
• Assistant Examiner(s): Allen; Cameron J
• Application Number:
  US12/289,968
• Publication Number:
  US 20090057229A1
• Time in Patent Office: 564 Days
• Field of Search: 952/63, 952/53, 210/749, 210/748.11
• US Class Current: 210/748.11
• CPC Class Codes: B01D 3/343 the substance being a gas

Abstract

The invention proposes a method of destruction of volatile organic and inorganic compounds in wastewater, this method includes following stages: stripping the aforementioned volatile compounds in a stripping-chemisorption column; preliminary heating the gaseous medium containing these volatile compounds in a first heat regenerator; thermal, flare or thermo-catalytic oxidation of the volatile compounds in circulating gaseous medium; cooling the gaseous medium in a second heat regenerator; chemisorption of acidic gases from the gaseous medium in the stripping-chemisorption column with stripping at the same time additional amount of the volatile compounds from the wastewater. After specific period, direction of the gaseous medium flow is alternated. The proposed method can be executed at elevated temperature. The invention includes as well systems realizing the proposed method.

Claims

1. A method of destruction of volatile organic and inorganic compounds in wastewater, the method comprising:

containing the wastewater in a tank;

stripping the volatile compounds from the wastewater and into a circulating gaseous medium, by at least one stripping-chemisorption column operatively connected to said tank;

pumping and circulating the wastewater by a pumping means through said at least one stripping-chemisorption column and said tank;

oxidizing the volatile compounds in said circulating gaseous medium, for forming oxidation products, by an oxidation means;

using a first heat regeneration means for preheating said circulating gaseous medium before oxidation of the volatile organic and inorganic compounds entering said oxidation means;

using a second heat regeneration means for accumulating heat from and cooling said circulating gaseous medium exiting said oxidation means;

chemisorption of said oxidation products of the volatile organic and inorganic compounds in said at least one stripping-chemisorption column by the wastewater.

2. The method of claim 1, further comprising alternation of flow direction of said circulating gaseous medium with alternating roles of said first and second heat regeneration means, wherein said second heat regeneration means is used for said preheating said circulating gaseous medium before said oxidation of the volatile organic and inorganic compounds entering said oxidation means, and wherein said first heat regeneration means is used for said accumulating heat from and cooling said circulating gaseous medium exiting said oxidation means.

3. The method of claim 2, wherein said alternation of flow direction is performed in accordance with change of temperatures in said first and second heat regeneration means.

4. The method of claim 2, wherein said alternation of flow direction is effected by a blowing means or by a system of shutting means.

5. The method of claim 2, wherein said alternation of flow direction is effected when average temperature is elevated up to a certain level in said first or in said second heat regeneration means used for said accumulating heat from and cooling said circulating gaseous medium exiting said oxidation means.

6. The method of claim 1, wherein said preheating said circulating gaseous medium entering said oxidation means, and said accumulating heat from and cooling said circulating gaseous medium exiting said oxidation means, are effected in one combined module of said first and second heat regeneration means and said oxidation means.

7. The method of claim 6, wherein said preheating said circulating gaseous medium by said first heat regeneration means, and said accumulating heat from and cooling said circulating gaseous medium by said second heat regeneration means, are effected in lower and upper sections, respectively, of said combined module.

8. The method of claim 1, wherein said oxidizing the volatile compounds in said circulating gaseous medium is effected by a type of oxidation selected from the group consisting of thermal oxidation, flare oxidation, and thermo-catalytic oxidation.

9. The method of claim 1, further comprising delivering oxygen or air into said circulating gaseous medium before or during said preheating said circulating gaseous medium before oxidation of the volatile organic and inorganic compounds entering said oxidation means.

10. The method of claim 9, wherein said delivering oxygen or air into said circulating gaseous medium is effected in accordance with amount of oxygen which is run out for said oxidizing the volatile compounds in said circulating gaseous medium by said oxidation means.

11. The method of claim 1, further comprising measuring concentration of the volatile compounds in the wastewater or in said circulating gaseous medium or/and measuring temperatures in different places of said circulating gaseous medium.

12. The method of claim 1, further comprising changing temperature of the wastewater in said tank.

13. The method of claim 12, wherein said changing temperature is effected by a heat exchanging module built-in or external to said tank.

14. The method of claim 12, wherein said changing temperature of the wastewater in said tank is effected in order to establish sufficiently high rate of evaporation of the volatile organic and inorganic compounds and, to prevent danger of explosion of said circulating gaseous medium.

15. The method of claim 12, wherein said changing temperature of the wastewater in said tank is effected such that said concentration of the volatile compounds in said circulating gaseous medium is significantly lower than a dangerous level which can cause explosion of said circulating gaseous medium.

16. The method of claim 1, performed in a continuous process, wherein sub-units of said stripping, said oxidation, and said chemisorption, are arranged in line and temperature of the wastewater is gradually elevated in a direction staffing from first said stripping-oxidation-chemisorption sub-unit, such that concentration of the volatile organic and inorganic compounds in said gaseous medium of each said stripping-oxidation-chemisorption sub-unit is lower than a dangerous level.

17. A method for monitoring and safely controlling destruction of volatile compounds in wastewater, the method comprising:

containing the wastewater in a tank;

changing temperature of the wastewater in said tank, by a heat exchanging module operatively connected to said tank;

stripping the volatile compounds from the wastewater and into a circulating gaseous medium, and chemisorption of oxidation products from said circulating gaseous medium, by at least one stripping-chemisorption column operatively connected to said tank;

pumping and circulating the wastewater through said at least one stripping-chemisorption column and said tank, by a pump;

oxidizing the volatile compounds in said circulating gaseous medium, for forming oxidation products, by an oxidation means;

preheating said circulating gaseous medium containing the volatile compounds entering said oxidation means, by a first heat regenerator;

accumulating heat from and cooling said circulating gaseous medium exiting said oxidation means, by a second heat regenerator;

measuring concentration of the volatile compounds in the wastewater or in said circulating gaseous medium or/and measuring temperatures in different places in the system, by a monitoring unit and sensors; and

safely controlling said changing temperature of the wastewater in said tank by said heat exchanging module, by control equipment, such that said concentration of the volatile compounds in said circulating gaseous medium is significantly lower than a dangerous level which can cause explosion of said circulating gaseous medium.