US3923955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for deodorising waste or exhaust gases
Assignee: Novartis Corp
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Filing: 1974-07-29
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Granted: 1975-12-02
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Expires: 1994-07-29
Abstract
Abstract A process for deodorising waste or exhaust gases, preferably containing CO2, in at least two washing stages with introduction of active chlorine, wherein a stream of the waste gas to be deodorised is subjected in an initial chlorine washing stage to the action of a washing liquid containing active chlorine and in a subsequent chlorine washing operation to the action of a washing liquid, likewise containing active chlorine, of alkaline pH is described. This process is improved by the following features: A. THE SUPPLIED ACTIVE CHLORINE IS PRACTICALLY FREE FROM CHLORINE DIOXIDE; B. A CONTENT OF AT LEAST 0.02 G OF ACTIVE CHLORINE PER LITRE OF WASHING LIQUID IS MAINTAINED IN AT LEAST ONE OF THE WASHING STAGES; C. THE PH-value of the washing liquid in the first washing stage, through which the waste gas to be purified, is flowing, is kept to between 4 and 9, and D. THE PH-value of the washing liquid in the subsequent washing stage is kept between 7 and 11, with the pH-value in the said subsequent washing stage being adjusted to remain higher by 0.3 to 4 than the pH-value in the first stage; E. ACTIVE ALKALI IS ADDED IN AN APPROXIMATELY STOICHIOMETRIC AMOUNT, CALCULATED ON TOTAL ACTIVE CHLORINE SUPPLIED, IN A SUBSEQUENT WASHING STAGE.
Inventors
- 👤 Volker Fattinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:33
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/14; B01D53/1456; B01D53/1475; B01D53/1406; B01D53/1493; B01D53/34; Y; Y02; Y02C; Y02C20/00; Y02C20/40
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
204 words
IN A PROCESS FOR DEODORISING WASTE OR EXHAUST GASES IN AT LEAST TWO WASHING STAGES WITH INTRODUCTION OF ACTIVE CHLORINE, WHEREIN A STREAM OF THE WASTE GAS TO BE DEODORISED IS SUBJECTED IN AN INITIAL CHLORINE WASHING STAGE TO THE ACTION OF A WASHING LIQUID CONTAINING ACTIVE CHLORINE, AND IN A SUBSEQUENT CHLORINE WASHING OPERATION TO THE ACTION OF A WASHING LIQUID, LIKEWISE CONTAINING ACTIVE CHLORINE, OF ALKALINE PH, THE IMPROVEMENT COMPRISING A. THE SUPPLIED ACTIVE CHLORINE IS PRACTICALLY FREE FROM CHLORINE DIOXIDE; B. A CONTENT OF AT LEAST 0.02 G OF ACTIVE CHLORINE PER LITER OF WASHING LIQUID IS MAINTAINED IN AT LEAST ONE OF THE WASHING STAGES; C. THE PH-VALUE OF THE WASHING LIQUID IN THE FIRST WASHING STAGE, THROUGH WHICH THE WASTE GAS TO BE PURIFIED, IS FLOWING, IS KEPT TO BETWEEN 4 AND 9, AND D. THE PH-VALUE OF THE WASHING LIQUID IN THE SUBSEQUENT WASHING STAGE IS KEPT BETWEEN 7 AND 11, WITH THE PHVALUE IN THE SAID SUBSEQUENT WASHING STAGE BEING ADJUSTED TO REMAIN HIGHER BY 0.3 TO 4 THAN THE PH-VALUE IN THE FIRST STAGE; E. ACTIVE ALKALI IS ADDED IN AN APPROXIMATELY STOICHIOMETRIC AMOUNT, CALCULATED ON THE TOTAL ACTIVE CHLORINE SUPPLIED, IN A SUBSEQUENT WASHING STAGE.
Claim 2
Dependent Claim
204 words
IN A PROCESS FOR DEODORISING WASTE OR EXHAUST GASES IN AT LEAST TWO WASHING STAGES WITH INTRODUCTION OF ACTIVE CHLORINE, WHEREIN A STREAM OF THE WASTE GAS TO BE DEODORISED IS SUBJECTED IN AN INITIAL CHLORINE WASHING STAGE TO THE ACTION OF A WASHING LIQUID CONTAINING ACTIVE CHLORINE, AND IN A SUBSEQUENT CHLORINE WASHING OPERATION TO THE ACTION OF A WASHING LIQUID, LIKEWISE CONTAINING ACTIVE CHLORINE, OF ALKALINE PH, THE IMPROVEMENT COMPRISING A. THE SUPPLIED ACTIVE CHLORINE IS PRACTICALLY FREE FROM CHLORINE DIOXIDE; B. A CONTENT OF AT LEAST 0.02 G OF ACTIVE CHLORINE PER LITER OF WASHING LIQUID IS MAINTAINED IN AT LEAST ONE OF THE WASHING STAGES; C. THE PH-VALUE OF THE WASHING LIQUID IN THE FIRST WASHING STAGE, THROUGH WHICH THE WASTE GAS TO BE PURIFIED, IS FLOWING, IS KEPT TO BETWEEN 4 AND 9, AND D. THE PH-VALUE OF THE WASHING LIQUID IN THE SUBSEQUENT WASHING STAGE IS KEPT BETWEEN 7 AND 11, WITH THE PHVALUE IN THE SAID SUBSEQUENT WASHING STAGE BEING ADJUSTED TO REMAIN HIGHER BY 0.3 TO 4 THAN THE PH-VALUE IN THE FIRST STAGE; E. ACTIVE ALKALI IS ADDED IN AN APPROXIMATELY STOICHIOMETRIC AMOUNT, CALCULATED ON THE TOTAL ACTIVE CHLORINE SUPPLIED, IN A SUBSEQUENT WASHING STAGE.
Claim 3
Dependent Claim
36 words
Process as described in claim 1, wherein the washing liquid containing active chlorine is obtained by addition of gaseous chlorine to the waste gas, to be deodorised, before its introduction into the first chlorine washing stage.
Claim 4
Dependent Claim
23 words
Process as described in claim 1, wherein the washing liquid containing active chlorine is obtained by injection of chlorine into the washing liquid.
Claim 5
Dependent Claim
21 words
Process as described in claim 1, wherein the employed source of active chlorine is aqueous hypochlorite solution, preferably sodium hypochlorite solution.
Claim 6
Dependent Claim
66 words
Process as described in claim 1, wherein the consumed alkali in the washing liquids is replaced by introduction of fresh alkali, preferably sodium hydroxide solution, in the subsequent chlorine washing stage, and wherein, optionally, washing liquid containing active chlorine is transferred from the subsequent washing stage to the first, either continuously or, preferably, in dosed amounts depending on the pH-value of the first chlorine washing stage.
Claim 7
Dependent Claim
22 words
Process as described in claim 1, wherein the waste gas to be deodorised contains at least 0.05 percent by volume of CO2.
Claim 8
Dependent Claim
47 words
Process as described in claim 1, wherein depending on the loss of chlorine in the first washing stage, washing liquid is fed back, continuously or in amounts controlled by the pH-value of the first stage, from the subsequent chlorine washing stage to the first chlorine washing stage.
Claim 9
Dependent Claim
32 words
Process as described in claim 1, wherein the content of active chlorine in the washing liquid of the subsequent chlorine washing stage is higher than that in the first chlorine washing stage.
Claim 10
Dependent Claim
49 words
Process as described in claim 8, wherein the concentration of active chlorine in the liquid of the subsequent chlorine washing stage is a number of times greater, preferably about two to twenty times greater, than the concentration of active chlorine in the liquid of the first chlorine washing stage.
Claim 11
Dependent Claim
51 words
Process as described in claim 2, wherein alkali (e.g. NaOH or Na2CO3) is added in the subsequent chlorine washing stage, simultaneously or after a short delay, as soon as active chlorine not coming from the washing liquid of the subsequent chlorine washing stage is added to the first chlorine washing stage.
Claim 12
Dependent Claim
33 words
Process as described in claim 1, wherein the concentration of active chlorine in the washing liquid of the first chlorine washing stage is about 0.1 to 3 g per liter of washing liquid.
Claim 13
Dependent Claim
57 words
Process as described in claim 1, wherein there is inserted between the first and the subsequent chlorine washing stage an intermediate washing stage, in which the waste gas is subjected to the action of a washing liquid having a pH-value of between that of the first chlorine washing stage and that of the last chlorine washing stage.
Claim 14
Dependent Claim
34 words
Process as described in claim 1, wherein the waste gas to be deodorised is subjected to at least one preliminary washing operation before introduction of the waste gas into the first chlorine washing stage.
Claim 15
Dependent Claim
25 words
Process as described in claim 1, wherein, with the presence of amines in the waste gas, the waste gas is subjected to an acid pre-treatment.
Claim 16
Dependent Claim
20 words
Process as described in claim 14, wherein the washing liquid in the acid pre-treatment contains hydrochloric acid or sulphuric acid.
Claim 17
Dependent Claim
40 words
Process as described in claim 13, wherein the washing liquid in the preliminary washing stage contains oxidation catalysts, with the aid of which the oxidisable constituents of the waste gas are caused to react with the oxygen of the atmosphere.
Claim 18
Dependent Claim
31 words
Process as described in claim 12, wherein two preliminary washing stages are used, of which the one operates with an acid washing liquid and the other with an oxidising washing liquid.
Claim 19
Dependent Claim
22 words
Process as described in claim 1, wherein the purified gas discharged from the subsequent chlorine washing stage is subjected to an after-oxidation.
Claim 20
Dependent Claim
17 words
Process as described in claim 18, wherein an ozone-containing washing liquid is used for the after-oxidation treatment.
Claim 21
Dependent Claim
19 words
Process as described in claim 18, wherein a washing liquid containing chlorine dioxide is used for the after-oxidation treatment.
Claim 22
Dependent Claim
19 words
Process as described in claim 18, wherein a washing liquid containing potassium permanganate is used for the after-oxidation treatment.
Claim 23
Dependent Claim
25 words
Process as descriBed in claim 1, wherein the pH-value of the washing liquid in the subsequent chlorine washing stage is maintained at 7.5 to 8.5.
References Cited (Backward Citations)
US2962344A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |