AU623928B2 - Gas chlorine dioxide generation - Google Patents
Gas chlorine dioxide generation Download PDFInfo
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- AU623928B2 AU623928B2 AU41634/89A AU4163489A AU623928B2 AU 623928 B2 AU623928 B2 AU 623928B2 AU 41634/89 A AU41634/89 A AU 41634/89A AU 4163489 A AU4163489 A AU 4163489A AU 623928 B2 AU623928 B2 AU 623928B2
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- Australia
- Prior art keywords
- chlorine dioxide
- solution
- process according
- gas stream
- gas
- Prior art date
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- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 title claims description 176
- 235000019398 chlorine dioxide Nutrition 0.000 title claims description 88
- 239000004155 Chlorine dioxide Substances 0.000 title claims description 87
- 239000000243 solution Substances 0.000 claims description 50
- 238000000034 method Methods 0.000 claims description 47
- 239000007789 gas Substances 0.000 claims description 41
- 239000007864 aqueous solution Substances 0.000 claims description 16
- 235000013312 flour Nutrition 0.000 claims description 14
- 238000011282 treatment Methods 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 239000010865 sewage Substances 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 8
- 238000000889 atomisation Methods 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 7
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 239000012530 fluid Substances 0.000 claims description 3
- 239000007792 gaseous phase Substances 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000003513 alkali Substances 0.000 claims description 2
- 230000000717 retained effect Effects 0.000 claims 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 12
- 239000000460 chlorine Substances 0.000 description 12
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 10
- 229910052801 chlorine Inorganic materials 0.000 description 10
- UKLNMMHNWFDKNT-UHFFFAOYSA-M sodium chlorite Chemical compound [Na+].[O-]Cl=O UKLNMMHNWFDKNT-UHFFFAOYSA-M 0.000 description 10
- 229960002218 sodium chlorite Drugs 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000003595 mist Substances 0.000 description 6
- 238000004061 bleaching Methods 0.000 description 5
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 3
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 3
- 108700024827 HOC1 Proteins 0.000 description 2
- 101100178273 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) HOC1 gene Proteins 0.000 description 2
- 239000005708 Sodium hypochlorite Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000005587 bubbling Effects 0.000 description 2
- QBWCMBCROVPCKQ-UHFFFAOYSA-N chlorous acid Chemical compound OCl=O QBWCMBCROVPCKQ-UHFFFAOYSA-N 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 239000003380 propellant Substances 0.000 description 2
- 238000011012 sanitization Methods 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 1
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- VCUFZILGIRCDQQ-KRWDZBQOSA-N N-[[(5S)-2-oxo-3-(2-oxo-3H-1,3-benzoxazol-6-yl)-1,3-oxazolidin-5-yl]methyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C1O[C@H](CN1C1=CC2=C(NC(O2)=O)C=C1)CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F VCUFZILGIRCDQQ-KRWDZBQOSA-N 0.000 description 1
- 241001482237 Pica Species 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- MYENLIKUFDIYQN-UHFFFAOYSA-N ac1l1wf1 Chemical compound O.[O]Cl=O MYENLIKUFDIYQN-UHFFFAOYSA-N 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910001919 chlorite Inorganic materials 0.000 description 1
- 229910052619 chlorite group Inorganic materials 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000011833 salt mixture Substances 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B11/00—Oxides or oxyacids of halogens; Salts thereof
- C01B11/02—Oxides of chlorine
- C01B11/022—Chlorine dioxide (ClO2)
- C01B11/028—Separation; Purification
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Treating Waste Gases (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Description
.1 i Hi n- r AUS 1442 P/00/011 4AUSTRALIA 6 6239 28 PATENTS ACT 1952-1973 COMPLETE SPECIFICATION
(ORIGINAL)
FOR OFFICE USE Form Int. Cl: Application Number: Lodged: Complete Specification-Lodged: r tt t e Priority: Related Art: Accepted: Published: TO BE COMPLETED BY APPLICANT Name of Applicant: te t Address of Applicant: C t c e C ctualnventor: c Actual Inventor: ICI Australia Operations Propietary Limited Industrial Property Section ICI Australia Operations Proprietary Limited P.O. Box 4311 1 Nicholson Street Melbourne 3001, Victoria Australia John Stewart CHALMERS Philip John BARLOW Industrial Property Section ICI Australia Operations Proprietary Limited P.O. Box 4311 1 Nicholson Street Melbourne 3001, Victoria Australia Adar zrs for Service: Complete Specification for the invention entitled: "GAS CHLORINE DIOXIDE GENERATION" The following statement is a full description of this invention, including the best method of performing it known to me:- "Note: The description is to be typed in double spacing, pica type face, in an area not exceeding 250 mm in depth and 160 mm in width, on tough white paper of good quality and it is to be inserted inside this form.
11710/76-L C,1 T~i[OMSON. Conimonwlh thGovernnienti rinter, Canberra 4
I
ii 4 o Gas Chlorine Dioxide Generation This Invention relates to a process for preparation of gaseous chlorine dioxide.
Chlorine dioxide has a range of industrial uses for bleaching and sanitizing. Typically, because of its explosive character, chlorine dioxide is manufactured at the point of use.
o o o o 0 10 0 0 0 *000 00*000 1 Q 9 0 0000 0000 e t C£ t tC I. C e Chlorine dioxide is generally prepared in aqueous solution by a method involving reduction of sodium chlorate wh*ch is generally convenient in large scale operations or by oxidation of chlorite, a process generally favoured in small scale processes.
In order to prepare gaseous chlorine dioxide methods involving bubbling a gas through a solution of chlorine dioxide have been reported.
We have found that chlorine dioxide gas can be more efficiently removed from solution by atomizing the chlorine dioxide solution.
Accordingly we provide a process for preparation of gaseous chlorine dioxide comprising atomizing an aqueous solution of chlorine dioxide.
c
C
Preferably the solution is atomized using a gaseous propellant which is preferably air.
By gaseous chlorine dioxide we mean chlorine dioxide in the form of the free gas as distinct from chlorine dioxide present in aqueous solution.
ii i-' r i 6 7 I i
I
-2- The temperature at which the solution is atomized is not narrowly critical but is typically in the range of from 5 to 50 0 C. Atomization at ambient temperature is convenient and generally preferred.
Atomization may be carried out by a range of techniques including using centrifugal disks, pressure nozzles, two fluid nozzles and electrostatic sprayers. Two fluid nozzles are generally preferred whereby, the solution is broken up by impingement with a high velocity stream of gas, preferably air, to provide droplets of, for example, average particle size in the range of from 10 to 150 microns.
o 0 ao *9 p oll,
C
Cf
CC.
C It The concentration of dissolved chlorine dioxide in the solution is typically from about 0.05 to 5g per litre. Preferably the concentration will be from about 2g to 5g of dissolved chlorine dioxide per litre of solution. Preferably the pH of the solution which is atomized is in the range of from 5 to 8 and more preferably from 6.5 to 7.
The nozzle used in atomization is preferably constructed of a corrosion resistant plastics material such as poly vinyl chloride.
The process of the invention has a range of applications for example in bleaching of wood pulp or flour, in sanitization and in control of odour.
Odour emissions from sewage treatment plants and pump stations, has Sfor many years been of major concern to municipal authorities. Local resident complaints regarding unacceptable sewage odours, hiave I significantly increased over recent years. There are various methods I7 1, r' -3of reducing or eliminating odour levels, however, many of these are only partially effective and are cost prohibitive. Therefore, controlling odour production in many sewage treatment systems is impractical, the result of which presents problems at points of heavy turbulence or aeration of the raw sewage. The normal problem areas for sewage odours are pump stations and the inlet areas of sewage treatment plants.
Eliminating sewage odours will always be a necessary part of this industry, therefore any cost effective control method will have great application.
One embodiment of the invention comprises treatment of foul air such as in a sewage treatment plant whereby foul air is contacted with an S atomized aqueous solution of chlorine dioxide.
Typically it is convenient to atomize the chlorine dioxide solution within an air space containing the foul air.
44o4 ii I2 'E~4 4 4 4,P It has been found that treatment with chlorine dioxide in the manner is a most efficient method of eliminating, or at least significantly reducing, the presence of hydrogen sulphide, a toxic gas which is the main contributor to the odour problem.
Typically in this embodiment the concentration of the solution to be atomized is about 50 to 500 mg/L as chlorine dioxide. It is convenient to generate the chlorine dioxide at pH 5 to 7 to produce in the range of from 0.1 to lOg chlorine dioxide per hour.
i I i i -4- Typically the dose rate of chlorine dioxide is in a ratio to hydrogen sulphide of at least 0.5 mole chlorine dioxide per mpi hydrogen sulphide and preferably in the range of from 0.5 mole to 1.5 mole per mole of hydrogen sulphide. A ratio of 0.9 mole chlorine dioxide per mole hydrogen sulphlde is preferred.
A water scrubber, optionally dosed with alkali to provide a pH of about 10 to 12, may be used to eliminate any remaining chlorine dioxide from the treated air.
In a preferred embodiment of the invention, which is particularly rt~t suited to flour treatment applications, the water mist produced by :E atomizing the chlorine dioxide solution is removed by suitable filtration means. We have found that by a process of atomization and filtration it is possible to liberate at least 90% and generally at least 95% of dissolved chlorine dioxide into the gaseous phase.
Accordingly we provide a process for preparation of gaseous chlorine dioxide comprising atomizing an aqueous solution of chlorine dioxide in to a gas stream and substantially removing the resulting liquid droplets by filtration without removing gaseous chlorine dioxide from the gaseous phase. A range of suitable filtration means may be used '0 to remove the liquid droplets such as mist eliminators or water traps.
The filtration means preferably comprises polypropylene-filters.
The said gas stream may be provided by the atomizing gas, that is the gas which is used as the propellant.
The chlorine dioxide solution may be atomized within a vessel containing an aqueous mixture, which may for example be the residual salt solution remaining after removal of chlorine dioxide atomization of a solution. A portion of the atomized solution will tend to condense and become incorporated into the aqueous mixture. The level of residual chlorine dioxide in the aqueous solution may be minimized by bubbling a gas through the aqueous mixture and into the gas steam.
Chlorine Dioxide has been used for many years in treatment of flour, however, until recently only two main gaseous C10 2 generation systems have been used world wide. One is the Dyox System designed by Wallace Tiernan, which reacts sodium chlorite with gaseous chlorine, to generate Chlorine Dioxide which is air stripped for injection into a flour agitator. The second process available is called the Hy-Kure process which uses a frozen Chlorine Dioxide hydrate which is stored at the site of use at low temperatures. When this hydrate is placed in water a solution of Chlorine Dioxide results. Chlorine Dioxide gas is produced by passing the solution through a stripping tower after which it is then fed to the flour agitator.
The present invention allows efficient removal of gaseous chlorine dioxide to the gas phase for immediate injection into the flour to be treated.
V V V *1 .1Ill t V Vt V VP V I V 11.
f' V C V 4 C LV Accordingly we provide a process for treatment of flour comprising: generating an aqueous solution of chlorine dioxide; atomizing the chlorine dioxide solution into a gas stream; substantially removing the resulting liquid droplets from the gas stream by filtration to 6 provide gaseous chlorine dioxide and treating flour with the gaseous chlorine dioxide.
The chlorine dioxide solution to be atomized in accordance with the process of the invention may be prepared by a range of techniques.
S The well known chlorine dioxide process involves reaction of chlorine in aqueous solution whereby chlorine hydrolysed to form hypochlorous acid in accordance with the following:- 71 C1 2 (gas) H 2 0 HOC1 HC1 000G 6 HOC1 HC1 2NaClO 2 2C10 2 2NaCl 00 Vo 0 10 The solution pH is preferably in the range of from 3 to 3.5 for this generation technique.
000a 4 V 4 An alternative generation technique comprises reaction of 0 molecular chlorine in aqueous solution with sodium chlorite to oo produce chlorine dioxide gas.
0 0 9 15 Cl 2 (gas) 2NaC10 2 2C10 2 2NaC1 In order to minimise undesirable side reactions it is generally preferred that the resulting chlorine dioxide solution has a concentration of from 4 to 5 g/L although this solution may be diluted prior to use.
Prior to reaction of sodium chlorite with chlorine in aqueous solution it is preferred that the solution pH be below 2 at which level about -7of the chlorine is in the form of hypochlorous acid. Hydrochloric acid or sulphuric acid is generally used to adjust the solutions pH, The invention will now be further described with reference to the attached drawings.
In the attached drawings: Fig 1 is a schematic drawing of a plant which incorporates equipment for producing free gaseous chlorine dioxide in .accordance with the process of the invention.
o a otee 00 00 o B Fresh water is fed through a standard commercially available water flow control and monitoring devices comprising water inlet line strainer water inlet solenoid value water pressure regulator, water rotameter and water flow alarm switches via a non-return valve into a commercially available chlorinator Sinjector 15 The chlorine gas is injected through the injector via the chlorinator from the gas cylinder The injector draws t chlorine gas under vacuum and the resultant chlorine solution is preferably maintained at greater than 500 milligrams per litre as C12.
If necessary sulphuric acid or hydrochloric acid is added from a holding tank (11) via a metering pump (10) to adjust the pH of the solution.
r4 i 8- Into this solution Is metered, from the reagent tank a quantity of sodium chlorite via metering pump Just before the reaction chamLer (15) where aqueous chlorine dioxide solution is produced.
Holding tanks (11) and (14) may be equipped with level float switches (12).
Chlorine dioxide solution is transferred to a holding tank (18) on a high/low level control system activated by a control float switch A sight glass (16) and concentration alarm (17) may be incorporated into the transfer line for monitoring purposes. The holding tank (18) is vented to end use process area.
0oe Free gaseous chlorine dioxide is produced in accordance with the process of the invention by transfer of chlorine dioxide from the holding tank (18) to the air atomizing nozzles (26) positioned within a gas stripping tank (19) via a metering pump (23) and line filter 15 The transfer line is regulated by a pulsation damper j Compressed air is transferred from a clean air supply to the nozzles (26) via air isolating solenoid valve air filter air t r, pressure underpressure switch (29) and air pressure regulator t The gas pressure is generally maintained at about 300 kpa but may be selected depending on the nozzle type, solution transfer rate and other factors.
Spray from the nozzles (26) are directed downward into the gas stripping tank (19) and a portion of the spray condenses and is collected in the tank Overflow from the stripping tank (19) is -9transferred to a waste tank (20) which retains the residual aqueous salt mixture before safe disposals.
The stripping tank and optionally also the waste tank (20) are equipped with a compressed air line (38) which bubbles air into the base of tanks (19) and A gas stream flow from the tanks (19) and (20) to the mist eliminators (37) and (33) is provideC by air from the atomizing nozzles (26) and compressed air line The mist formed by atomization is passed through secondary mist eliminator (37) and primary mist eliminator (33) to remove liquid particles and the 10 resulting free gaseous chlorine dioxide may be transferred to storage S. or is preferably used immediately in its intended applicatior, for example in flour bleaching.
S. 9 A sight glass (34) may be incorporated into the lime to allow viewing of the gas produced.
,I x 1 Although the above generator operating description is based on the 15 utilization of sodium chlorite and gaseous chlorine, this style of I.1':t generator may also utilise the generation technique whereby sodium chlorite, sodium hypochlorite, and hydrochloric acid are the chemical I reactants. The functional difference between this style of generation I c. :20 and the gas chlorine system, as described above, is that the gas chlorine injector is removed and hydrochloric acid is metered into the dilution water after the non-return valve. Sodium hypochlorite is then metered into dilution water prior to a primary reactor, which is a simple PVC packed column to promote mixing and convert the hypochlorite to hypochlorous acid. The sodium chlorite solution is injected prior to the Cl02 reactor.
10 SFree gaseous chlorine dioxide may be thus generated in accordance with the above whereby an aqueous solution of chlorine dioxide Is initially ,I generated by for example reaction of equal volumes of a 9% solution of hydrochloric acid and 7.5% solution of sodium chlorite.
The above described process has application in a variety of treatments including chemical maturing of flour products, odour control, gas bleaching of flour products, odour control, gas bleaching in various -food industries and cold room sterilization.
Example 1 10 This Example demonstrates the use of the present invention in odour control.
Sets 'Chlorine dioxide solution of concentration 200 mg/L as C10 2 and pH to 6 was air atomized into a wet well of sewage treatment pump station I using a dose rate of approximately 0.9 mole C102 per mole H 2
S.
The chlorine dioxide solution used was generated by reaction of gaseous chlorine and sodium chlorite at a pH between 5 and 6 mole at a rate of 0.5g/hour of ClO2.
It ti t it V The emission of odours was significantly reduced.
Example 2 This Example demonstrates the use of the process of the present invention to generate free gaseous chlorine dioxide for use in flour treatment.
J
11 The process described in hereinbefore with reference to Fig 1 was used in preparation of gaseous chlorine dioxide with the exception that the aqueous chlorine dioxide solution was prepared by reaction of 9% hydrochloric acid and 7.5% solution of sodium chlorite. An air pressure of 300 kPa was used to air atomize a chlorine dioxide solution of concentration of approximate'y 4g/L C10 2 Gaseous chlorine dioxide was generated at a rate of about 150g/hour and was used to treat 7.5 tonnes of flour per hour at a close rate of 20 ppm.
Ce t t t "t
Claims (14)
1. A process for preparation of gaseous chlorine dioxide as hereinabove described, the process comprising atomizing an aqueous solution of chlorine dioxide into a gas stream and substantially removing the resulting liquid droplets by filtration without removing gaseous chlorine dioxide from the gaseous phase.
2. A process according to claim 1 wherein the solution is atomized using at least one two-fluid nozzle whereby the solution is broken up by impingement with a high velocity stream of gas.
3. A process according to claim 2 wherein the gas is air.
4. A process according to claim 1 wherein the chlorine dioxide solution is atomized to produce droplets of average size in the range of from 10 to 3.50 microns. U A process according to claim 1 wherein the chlorine dioxide solution has a concentration in the range of from 0.05 to 5 grams of chlorine dioxide per litre of solution.
6. A process according to claim 5 wherein the chlorine dioxide solution has a concentration in the range of from 2 to 5 grams of chlorine dioxide per Slitre of solution.
7. A process according to claim 1 wherein the gaseous chlorine dioxide is used to treat foul air by contacting the foul air with the atomized solution. 4 Y -p, $~j I :2 I t2 t t *tt tE t 13
8. A process according to claim 7 wherein the foul air comprises hydrogen sulphide and is treated using a dose rate of from 0.5 to 1.5 mole chlorine dioxide per mole hydrogen sulphide.
9. A process according to claim 7 for treating foul air in a sewage treatment plant comprising contacting the foul air with an atomized aqueous solution of chorine dioxide and subsequently removing residual chlorine dioxide by passing the treated air through a water scrubber dosed with alkali to provide a pH iq the range of from 10 to
12. A process for preparation of gaseous chlorine dioxide according to claim 1 and comprising atomizing an aqueous solution of chlorine dioxide into a gas stream and filtering the gas stream to remove liquid droplets without removing gaseous chlorine dioxide. 11. A process according to claim 10 wherein the gas stream is filtered using polyprcpylene-filters. 12. A process according to claim 10 wherein at least 90% of the chlorine dioxide originally present in the aqueous solution of chlorine dioxide is retained in the filtered gas stream.
13. A process according to claim 10 wherein at least 95% of the chlorine dioxide originally present in te aqueous solution of chlorine dioxide is retained in the filtered gas stream.
14. A process according to claim 10 wherein the chlorine dioxide solution comprises in the range of from 2 to 5 grams of chlorine dioxide per litre of solution. I Ct trot 'I trot cEt,. *s Ott r 4 14 A process according to claim 14 wherein the chlorine dioxide solution comprises in the range of from 4 to 5 grams per-litr of fe-r cD- sotuorn chlorine dioxide
16. A process according to claim 10 wherein the chlorine dioxide solution is atomized into a gas stream within a vessel containing an aqueous mixture such that at least a portion of the liquid particles resulting from atomization are condensed and the.reby incorporated in the aqueous mixture and wherein a gas is bubbled through the aqueous mixture and into the gas stream.
17. A process according to claim 10 wherein the resulting gas stream is used in treatment of flour. ij ii g i d i: r:I- i ii b 8 jl ~t :I t1 ft t t. ftI ttf Dated this day of September 1989 ICI AUSTRALIA OPERATIONS PROPRIETARY LIMITED By its Duly Authorized Officer Raymond L Evans re t i. t E C re c r -1 \'d
1887.rlel3
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPJ055488 | 1988-09-22 | ||
| AUPJ0554 | 1988-09-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU4163489A AU4163489A (en) | 1990-03-29 |
| AU623928B2 true AU623928B2 (en) | 1992-05-28 |
Family
ID=3773391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU41634/89A Ceased AU623928B2 (en) | 1988-09-22 | 1989-09-22 | Gas chlorine dioxide generation |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU623928B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU409986B2 (en) * | 1964-08-13 | 1967-02-09 | Electric Reduction Company Of Canada | Improvements inthe manufacture of chlorine dioxide |
| AU584485B2 (en) * | 1985-12-18 | 1989-05-25 | Superior Plus Inc. | Membrane pervaporation process for chlorine dioxide |
-
1989
- 1989-09-22 AU AU41634/89A patent/AU623928B2/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU409986B2 (en) * | 1964-08-13 | 1967-02-09 | Electric Reduction Company Of Canada | Improvements inthe manufacture of chlorine dioxide |
| AU435167B2 (en) * | 1967-10-12 | 1973-05-17 | Method of simultaneously producing chlorine dioxide anda salt ofa strong acid | |
| AU584485B2 (en) * | 1985-12-18 | 1989-05-25 | Superior Plus Inc. | Membrane pervaporation process for chlorine dioxide |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4163489A (en) | 1990-03-29 |
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