GB2058602A - An apparatus and a process for recovering chlorine dioxide - Google Patents
An apparatus and a process for recovering chlorine dioxide Download PDFInfo
- Publication number
- GB2058602A GB2058602A GB8030444A GB8030444A GB2058602A GB 2058602 A GB2058602 A GB 2058602A GB 8030444 A GB8030444 A GB 8030444A GB 8030444 A GB8030444 A GB 8030444A GB 2058602 A GB2058602 A GB 2058602A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tower
- liquid
- solution
- chlorine dioxide
- tank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 239000004155 Chlorine dioxide Substances 0.000 title claims abstract description 34
- 235000019398 chlorine dioxide Nutrition 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 69
- 239000007789 gas Substances 0.000 claims abstract description 62
- 239000007788 liquid Substances 0.000 claims abstract description 58
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 29
- UKLNMMHNWFDKNT-UHFFFAOYSA-M sodium chlorite Chemical compound [Na+].[O-]Cl=O UKLNMMHNWFDKNT-UHFFFAOYSA-M 0.000 claims abstract description 27
- 229960002218 sodium chlorite Drugs 0.000 claims abstract description 27
- 235000011121 sodium hydroxide Nutrition 0.000 claims abstract description 23
- 238000012856 packing Methods 0.000 claims abstract description 7
- 239000004753 textile Substances 0.000 claims description 13
- 238000004061 bleaching Methods 0.000 claims description 9
- 238000007670 refining Methods 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 2
- 239000002699 waste material Substances 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 34
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000011084 recovery Methods 0.000 description 5
- 239000011259 mixed solution Substances 0.000 description 4
- PFUVRDFDKPNGAV-UHFFFAOYSA-N sodium peroxide Chemical compound [Na+].[Na+].[O-][O-] PFUVRDFDKPNGAV-UHFFFAOYSA-N 0.000 description 3
- 238000006298 dechlorination reaction Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000009931 harmful effect Effects 0.000 description 2
- 231100000614 poison Toxicity 0.000 description 2
- 230000007096 poisonous effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- 238000003915 air pollution Methods 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910001919 chlorite Inorganic materials 0.000 description 1
- 229910052619 chlorite group Inorganic materials 0.000 description 1
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/68—Halogens or halogen compounds
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Treatment Of Fiber Materials (AREA)
Abstract
Apparatus for recovering chlorine dioxide from an exhaust gas comprises a gas treating tower (2) filled with packing such as Raschig rings (4) for ensuring good contact between the gas and a liquid, an inlet (1) for chlorine dioxide gas at the lower part of the tower, a liquid tank (6) beneath the inlet for chlorine dioxide gas, liquid jet nozzles (10') at the top of the tower, a pump (8) connected for circulating liquid from the liquid tank to the tower through the liquid jet nozzles, means such as a pair of pumps (14, 15) respectively for supplying hydrogen peroxide solution and caustic soda solution to the tower through the liquid jet nozzles, and means such as a densitometer (16) provided in the liquid tank, for measuring the concentration of sodium chlorite solution in the liquid tank. By using this apparatus there is provided a process for conveniently recovering waste chlorine dioxide gas as sodium chlorite. <IMAGE>
Description
SPECIFICATION
An apparatus and a process for recovering chlorine dioxide.
The present invention relates to an apparatus and a process for recovering chlorine dioxide from an exhaust gas. By using the apparatus and process of the invention harmful chlorine dioxide gas exhausted, for example, from a Perble Range used continuously to refine and/or bleach textile products such as cloths and yarns with sodium chlorite, can be recovered conveniently as useful sodium chlorite for further use without discharging the gas to atmosphere.
Sodium chlorite has been used widely for refining and/or bleaching textile products.
Typically a textile product padded with sodium chlorite may be steamed in a reaction chamber to achieve refining and/or bleaching utilizing the oxidizing power of sodium chlorite. Although a part of thesodium chlorite is neutralized by reaction with the textile product and thereby loses its harmful properties, a greater part thereof is decomposed to form poisonous chlorine dioxide gas. Chlorine dioxide gas thus formed must be subjected to a dechlorination treatment outside the reaction chamber before discharging the gas to atmosphere in order to prevent pollution.
However, dechlorination treatment of chlorine dioxide gas is troublesome insofar as it involves the use of large quantities of water and treatment agent, and the treatment apparatus accordingly must be a large one.
We have now found that chlorine dioxide gas can be recovered as sodium chlorite in an effective manner using apparatus employing a packed tower in which chlorine dioxide gas evolved in the course of refining and/or bleaching a textile product is contacted with hydrogen peroxide and caustic soda.
Accordingly, the present invention provides apparatus for recovering chlorine dioxide from an exhaust gas, which apparatus comprises a gas treating tower having packing for ensuring good contact between the gas and a liquid, an inlet for chlorine dioxide-containing exhaust gas at the lower part of the tower, a liquid tank at the lower part of the tower beneath the inlet for exhaust gas, liquid jet nozzles at the upper part of the tower above the packing, a pump connected for circulating liquid from the liquid tank to the tower through the liquid jet nozzles, means respectively for supplying hydrogen peroxide solution and caustic soda solution to the tower through the liquid jet nozzles, and means for measuring the concentration of sodium chlorite solution in the liquid tank.
The invention also provides a process for recovering chlorine dioxide from an exhaust gas, which process comprises passing the exhaust gas upwards through a packed tower countercurrent to a descending stream of liquid comprising a mixture of hydrogen peroxide solution and caustic soda solution, the resultant sodium chlorite solution being collected at the base of the tower
and discharged when its concentration reaches a desired value.
Sodium chlorite regenerated from chlorine dioxide gas by using the above apparatus and process can be reused by circulating it to a textile product refining and/or bleaching stage, thus preventing the problem of air pollution due to chlorine dioxide gas and conserving chemical resources.
The invention will now be described by way of example with reference to the accompanying drawing which shows in diagrammatic form one embodiment of an apparatus in accordance with the invention.
Referring to the drawing, the apparatus shown comprises a gas exhaust pipe 1 connected at its upstream end to a reaction chamber for refining and/or bleaching a textile product such as a Perble
Range (not shown), and at its downstream end to a gas inlet in the lower part of a gas treating tower 2. A plurality of permeable nets 3 are provided in multistages in the interior of the gas treating tower 2, and Raschig rings 4 are piled on each of the nets 3 so as to ensure good contact between gas and liquid in the tower. A waste gas discharge pipe 5 is provided at the top of the tower 2.
At the lower part of the tower 2, beneath the chlorine dioxide gas inlet there is a liquid tank 6, which has an overflow opening 7 in the upper part of one wall, and in the lower part of one wall a liquid flow pipe 9 communicating with a pump 8.
A liquid circulation pipe 10 is connected to the pump 8 to return liquid in the liquid tank 6 to the top of the gas treating tower 2 so that there is a circulation of liquid which flows down through the gas treating tower countercurrently to the gas.
The top end portion of pipe 10 comprises a plurality of liquid jet nozzles 10' which can jet liquid into the top of the gas treating tower. The liquid which overflows from the overflow opening 7 of the liquid tank 6 is received in a recovery tank 11.
The apparatus also includes a tank 12 for hydrogen peroxide solution, a tank 13 for caustic soda solution, together with quantitative pumps 14 and 15 respectively to supply hydrogen peroxide solution and caustic soda solution to the suction side of the pump 8 as a mixed solution.
The quantitative pumps 14 and 15 may be operated manually or automatically. There are also flow-meters 17 and 1 8 respectively for hydrogen peroxide solution and caustic soda solution, and a densitometer 16 is provided in the liquid tank 6 to measure the concentration of sodium chlorite solution therein.
A process for recovering chlorine dioxide gas using an apparatus as described above may be carried out as follows:
In order to start the process, a certain amount of each of hydrogen peroxide solution and caustic soda solution is introduced into the liquid tank 6, and the mixture of solutions is circulated through the gas treating tower by driving the pump 8. The circulation of liquid from tank 6 is effected continuously throughout the process. In addition, hydrogen peroxide solution from the tank 12 and caustic soda solution from the tank 13 are also supplied to the gas treating tower by driving the quantitative pumps 14 and 15. The two solutions are mixed by passing through the liquid circulation pipe, and the mixed solutions, or sodium peroxide solution formed therefrom, are jetted through the liquid jet nozzles 10' into the gas treating tower 2.
Then, chlorine dioxide gas, for instance with a concentration of from 300 to 360 ppm, coming from a Perble Range for refining and/or bleaching a textile product is supplied through the exhaust pipe 1 thereof to the lower part of the gas treating tower 2 so that the gas flows upwards through the tower. The mixed solutions come into contact with chlorine dioxide gas ascending through the gas treating tower 2, the contact being uniform due to the effects of the jetting of the solution and of the
Raschig rings 4 piled on each of the permeable nets 3. Reaction between the chlorine dioxide and the mixed solutions affords sodium chlorite solution which falls down into the liquid tank 6 together with excess hydrogen peroxide and
caustic soda.
The supply of hydrogen peroxide solution and caustic soda solution from the tanks 12 and 13 is stopped when the amount of the solution accumulated in the liquid tank 6 is just about to overflow through the overflow opening 7 of the liquid tank. Circulation of the solution from the liquid tank 6 is then continued further until the concentration of the sodium chlorite solution reaches a prescribed value, given by measuring the concentration thereof using the densitometer 16, preferably that at which the contents of hydrogen peroxide and caustic soda, or the content of sodium peroxide formed therefrom, become practically zero.
Then, prescribed amounts of hydrogen peroxide solution and caustic soda solution are jetted through the liquid jet nozzles 10' by operating the quantitative pumps 14 and 15. The solution remaining in the gas treating tower and held by the Raschig rings is exchanged for the freshly added solutions, it flows down into the liquid tank
6, and the excess of the solution accumulated in the liquid tank is pushed to overflow through the overflow opening 7 into the recovery tank 1 The
resultant sodium chlorite solution stored in the
recovery tank 1 1 is highly concentrated and perfectly free from chlorine dioxide gas. Although
a small amount of sodium peroxide may be
contained therein, there is no problem in reusing the sodium chlorite solution obtained for the treatment of textile products.
After completing the addition of hydrogen
peroxide solution and caustic soda solution in this
stage, the solution remaining in the liquid tank is further circulated to increase the content of
sodium chlorite in the solution, and when the densitometer 16 again indicates that the
concentration has reached the prescribed value as
in the preceding stage, prescribed amounts of
hydrogen peroxide solution and caustic soda
solution are once again added to the gas treating tower as before to discharge sodium chlorite solution from the liquid tank to the recovery tank.
The recovery of waste chlorine dioxide gas as concentrated sodium chlorite solution is continued successively in this way.
The necessary amounts of hydrogen peroxide and caustic soda corresponding to the concentration and amount of chlorine dioxide gas supplied to the gas treating tower as well as the amount of sodium chlorite regenerated therefrom can be estimated by calculation, but since the necessary relationships between these chemicals is not within the scope of the present invention, the calculation formulas therefor are not given.
By using the apparatus and process of the present invention, chlorine dioxide gas exhausted from processes for refining and/or bleaching a textile material can be contacted with a solution containing hydrogen peroxide and caustic soda, so that waste chlorine dioxide gas can be recovered effectively and continuously as a sodium chlorite solution having a high concentration. Sodium chlorite solution thus regenerated can be repeatedly applied beneficially for refining and/or bleaching textile products. The present invention has the further advantage of providing means to absorb poisonous chlorine dioxide gas perfectly in a gas treating tower and thus to enable the discharge of the waste gas therefrom to atmosphere without causing the problems of pollution.
Claims (15)
1. Apparatus for recovering chlorine dioxide from an exhaust gas, which apparatus comprises a gas tre.ating tower having packing for ensuring good contact between the gas and a liquid, an inlet for chlorine dioxide-containing exhaust gas at the lower part of the tower, a liquid tank at the lower part of the tower beneath the inlet for exhaust gas, liquid jet nozzles at the upper part of the tower above the packing, a pump connected for circulating liquid from the liquid tank to the tower through the liquid jet nozzles, means respectively for supplying hydrogen peroxide solution and caustic soda solution to the tower through the liquid jet nozzles, and means for measuring the concentration of sodium chlorite solution in the liquid tank.
2. Apparatus according to claim 1, wherein the packing comprises Raschig rings.
3. Apparatus according to claim 1 or claim 2, wherein the packing is arranged in a plurality of stages within the tower.
4. Apparatus according to any one of the preceding claims, wherein the means respectively for supplying hydrogen peroxide solution and caustic soda solution comprises a pair of pumps.
5. Apparatus according to any one of the preceding claims, including a tank for hydrogen peroxide solution and a tank for caustic soda solution.
6. Apparatus according to any one of the preceding claims, which includes means for mixing the hydrogen peroxide and caustic soda solutions prior to their supply to the liquid jet nozzles.
7. Apparatus according to any one of the preceding claims, wherein the means for measuring concentration in the liquid tank is a densitometer disposed within the tank.
8. Apparatus according to any one of the preceding claims, which includes an overflow tank disposed adjacent the liquid tank and an opening in an upper portion of a wall of the liquid tank whereby liquid overflowing from the liquid tank is collected in the overflow tank.
9. Apparatus for recovering chlorine dioxide from an exhaust gas substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.
10. A process for recovering chlorine dioxide from an exhaust gas, which process comprises passing the exhaust gas upwards through a packed tower countercurrent to a descending stream of liquid comprising a mixture of hydrogen peroxide solution and caustic soda solution, the resultant sodium chlorite solution being collected at the base of the tower and discharged when its concentration reaches a desired value.
1 A process according to claim 10, wherein fresh hydrogen peroxide solution and/or fresh caustic soda solution are supplied to the tower in a first stage, a second stage is effected without such supply until the sodium chlorite solution achieves the desired concentration, and in a third stage fresh solutions are supplied to the tower to effect said discharge.
12. A process according to claim 10 or claim 11, wherein the exhaust gas is derived from a refining and/or bleaching stage in a textile product treatment.
13. A process according to claim 12, wherein the sodium chlorite is recirculated to the textile product treatment.
14. A process according to any one of claims 10 to 13, which is effected using apparatus according to any one of claims 2 to 9.
15. Sodium chlorite when produced as a source of latent chlorine dioxide using apparatus according to any one of claims 1 to 9 or by a process according to any one of claims 10 to 14.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12123979A JPS5645749A (en) | 1979-09-20 | 1979-09-20 | Recovery and treatment equipment for chlorine dioxide gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2058602A true GB2058602A (en) | 1981-04-15 |
Family
ID=14806343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8030444A Withdrawn GB2058602A (en) | 1979-09-20 | 1980-09-19 | An apparatus and a process for recovering chlorine dioxide |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5645749A (en) |
| DE (1) | DE3035366A1 (en) |
| GB (1) | GB2058602A (en) |
| IT (1) | IT1141062B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5334224A (en) * | 1992-03-11 | 1994-08-02 | Sando Iron Works Co., Ltd. | Method for continuous pretreatment of a cloth |
| WO2012021113A3 (en) * | 2010-07-13 | 2012-04-05 | Kare Muhendislik Cevre Teknolojileri Sanayi Ve Ticaret Anonim Sirketi | Tower mechanism that removes soot and smell in the air |
| WO2016137337A1 (en) * | 2015-02-25 | 2016-09-01 | Genera Limited | Method and apparatus for fumigant gas capture |
| WO2018026260A1 (en) | 2016-08-05 | 2018-02-08 | Cheng Chew Kong | System and method for recovering sodium hypochlorite from exhaust chlorine gas |
-
1979
- 1979-09-20 JP JP12123979A patent/JPS5645749A/en active Pending
-
1980
- 1980-09-19 IT IT8024781A patent/IT1141062B/en active
- 1980-09-19 GB GB8030444A patent/GB2058602A/en not_active Withdrawn
- 1980-09-19 DE DE19803035366 patent/DE3035366A1/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5334224A (en) * | 1992-03-11 | 1994-08-02 | Sando Iron Works Co., Ltd. | Method for continuous pretreatment of a cloth |
| WO2012021113A3 (en) * | 2010-07-13 | 2012-04-05 | Kare Muhendislik Cevre Teknolojileri Sanayi Ve Ticaret Anonim Sirketi | Tower mechanism that removes soot and smell in the air |
| WO2016137337A1 (en) * | 2015-02-25 | 2016-09-01 | Genera Limited | Method and apparatus for fumigant gas capture |
| WO2018026260A1 (en) | 2016-08-05 | 2018-02-08 | Cheng Chew Kong | System and method for recovering sodium hypochlorite from exhaust chlorine gas |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1141062B (en) | 1986-10-01 |
| DE3035366A1 (en) | 1981-04-09 |
| IT8024781A0 (en) | 1980-09-19 |
| JPS5645749A (en) | 1981-04-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |