GB2167396A - Method for the treatment of exhaust gas - Google Patents
Method for the treatment of exhaust gas Download PDFInfo
- Publication number
- GB2167396A GB2167396A GB08523742A GB8523742A GB2167396A GB 2167396 A GB2167396 A GB 2167396A GB 08523742 A GB08523742 A GB 08523742A GB 8523742 A GB8523742 A GB 8523742A GB 2167396 A GB2167396 A GB 2167396A
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- Prior art keywords
- treatment
- stage
- catalytic
- ammonia
- exhaust gas
- Prior art date
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- 238000000034 method Methods 0.000 title claims description 34
- 239000007789 gas Substances 0.000 claims abstract description 71
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 60
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000000126 substance Substances 0.000 claims abstract description 39
- 230000003197 catalytic effect Effects 0.000 claims abstract description 34
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 24
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 21
- 230000001590 oxidative effect Effects 0.000 claims abstract description 19
- 239000003054 catalyst Substances 0.000 claims description 15
- 238000009434 installation Methods 0.000 claims description 14
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 9
- 150000002897 organic nitrogen compounds Chemical class 0.000 claims description 7
- 239000010970 precious metal Substances 0.000 claims description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 6
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052763 palladium Inorganic materials 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 claims description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 2
- 229910052741 iridium Inorganic materials 0.000 claims description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052762 osmium Inorganic materials 0.000 claims description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 claims description 2
- 229910052703 rhodium Inorganic materials 0.000 claims description 2
- 239000010948 rhodium Substances 0.000 claims description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052707 ruthenium Inorganic materials 0.000 claims description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 abstract description 28
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 6
- -1 secbutyl amines Chemical class 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000013067 intermediate product Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- YNAVUWVOSKDBBP-UHFFFAOYSA-N Morpholine Chemical compound C1COCCN1 YNAVUWVOSKDBBP-UHFFFAOYSA-N 0.000 description 2
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- KAESVJOAVNADME-UHFFFAOYSA-N Pyrrole Chemical compound C=1C=CNC=1 KAESVJOAVNADME-UHFFFAOYSA-N 0.000 description 2
- 229910052776 Thorium Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- PAFZNILMFXTMIY-UHFFFAOYSA-N cyclohexylamine Chemical compound NC1CCCCC1 PAFZNILMFXTMIY-UHFFFAOYSA-N 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 2
- 238000006864 oxidative decomposition reaction Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- WGYKZJWCGVVSQN-UHFFFAOYSA-N propylamine Chemical compound CCCN WGYKZJWCGVVSQN-UHFFFAOYSA-N 0.000 description 2
- 238000007669 thermal treatment Methods 0.000 description 2
- 239000002918 waste heat Substances 0.000 description 2
- JSZOAYXJRCEYSX-UHFFFAOYSA-N 1-nitropropane Chemical compound CCC[N+]([O-])=O JSZOAYXJRCEYSX-UHFFFAOYSA-N 0.000 description 1
- CDULGHZNHURECF-UHFFFAOYSA-N 2,3-dimethylaniline 2,4-dimethylaniline 2,5-dimethylaniline 2,6-dimethylaniline 3,4-dimethylaniline 3,5-dimethylaniline Chemical class CC1=CC=C(N)C(C)=C1.CC1=CC=C(C)C(N)=C1.CC1=CC(C)=CC(N)=C1.CC1=CC=C(N)C=C1C.CC1=CC=CC(N)=C1C.CC1=CC=CC(C)=C1N CDULGHZNHURECF-UHFFFAOYSA-N 0.000 description 1
- CDAWCLOXVUBKRW-UHFFFAOYSA-N 2-aminophenol Chemical class NC1=CC=CC=C1O CDAWCLOXVUBKRW-UHFFFAOYSA-N 0.000 description 1
- PLAZTCDQAHEYBI-UHFFFAOYSA-N 2-nitrotoluene Chemical compound CC1=CC=CC=C1[N+]([O-])=O PLAZTCDQAHEYBI-UHFFFAOYSA-N 0.000 description 1
- XBPCUCUWBYBCDP-UHFFFAOYSA-N Dicyclohexylamine Chemical compound C1CCCCC1NC1CCCCC1 XBPCUCUWBYBCDP-UHFFFAOYSA-N 0.000 description 1
- GYCMBHHDWRMZGG-UHFFFAOYSA-N Methylacrylonitrile Chemical compound CC(=C)C#N GYCMBHHDWRMZGG-UHFFFAOYSA-N 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 150000003939 benzylamines Chemical class 0.000 description 1
- 150000008363 butyronitriles Chemical class 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 150000003941 n-butylamines Chemical class 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- MCSAJNNLRCFZED-UHFFFAOYSA-N nitroethane Chemical compound CC[N+]([O-])=O MCSAJNNLRCFZED-UHFFFAOYSA-N 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 150000002830 nitrogen compounds Chemical class 0.000 description 1
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 description 1
- VLZLOWPYUQHHCG-UHFFFAOYSA-N nitromethylbenzene Chemical class [O-][N+](=O)CC1=CC=CC=C1 VLZLOWPYUQHHCG-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000768 polyamine Polymers 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 150000005619 secondary aliphatic amines Chemical class 0.000 description 1
- YBRBMKDOPFTVDT-UHFFFAOYSA-N tert-butylamine Chemical compound CC(C)(C)N YBRBMKDOPFTVDT-UHFFFAOYSA-N 0.000 description 1
- 150000003510 tertiary aliphatic amines Chemical class 0.000 description 1
- 150000004992 toluidines Chemical class 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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
-
- 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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
-
- 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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
- Incineration Of Waste (AREA)
Abstract
In order to reduce the content of primary harmful substances containing organically combined nitrogen and/or hydrogen cyanide in exhaust gases, the exhaust gases are treated in a first treatment stage by an oxidizing, thermal and/or catalytic treatment and the resulting gas stream is then treated catalytically after the addition of ammonia.
Description
SPECIFICATION
Method for the treatment of exhaust gas
This invention relates to a method for the treatment of exhaust gas to reduce the concentration of harmful substances, to a method of improving existing thermal and/or catalytic exhaust gas treatment installations, and also to an exhaust gas treatment installation.
Thermal afterburning (TAB) is known as a method for the oxidative decomposition of harmful substances in exhaust gas..
From a series of basic investigations into the thermal afterburning of harmful substances in exhaust gases, it can be shown that, in the majority of cases the installation in which the TAB is carried out has to be designed according to the oxidation conditions of the intermediate products (secondary harmful substances), principally carbon monoxide (CO), which arise during the TAB, and accordingly high operating temperatures well above 750 C, are necessary.
In particular, in the case of harmful substances of emission class Ill as degined in "Technische
Anleitung zur Reinhaltung der Luft" (=Technical Guide to Keeping the Air Pure), hereinafter called "TA air" for simplicity, the permissible residual concentrations of primary harmful substances (300 mg./m.3) (Norm-m.3) may be reached at temperatures between 500 and 600 C. whereas a residual CO concentration of a maximum 100 mg./m.3, which is to be regarded as acceptable, can only be reached above 800 C.
In order to eliminate secondary harmful substances, therefore, the exhaust gas must be treated at substantially higher temperatures than would be necessary for the elimination of the primary harmful substances themselves. Because of this necessity, the conventional treatment of exhaust gas becomes substantially more costly from both a technical and economic point of view than it needs to be on the basis of the actual cause.
If exhaust gas containing organic nitrogen compounds and/or hydrogen cyanide is to be treated in a TAB installation, then additional problems arise through the formation of further secondary harmful substances, of which oxides of nitrogen (NO,) are particularly troublesome secondary harmful substances, which are preferentially formed at high temperatures, partly from elemental nitrogen present in the exhaust gas.
In the treatment of exhaust gas containing organic nitrogen compounds, hydrogen cyanide is formed as a further and dangerous secondary harmful substance. In so far as hydrogen cyanide does not emerge in the resulting stream of gas, it is converted in the course of conventional exhaust gas treatment methods more or less into NO,, so that NO, is also formed from hydrogen cyanide-be it present as a primary or secondary harmful substance. Owing to the contrary effects, namely that primary or secondary harmful substances are only removed at high temperatures and the formation of NO, increases with higher temperatures, TAB is not suitable for the treatment of exhaust gas which contains organic nitrogen compounds and/or hydrogen cyanide.
Another method for the oxidative decomposition of harmful substances in exhaust gas is catalytic afterburning (CAB), which generally allows operations to be carried out at lower temperatures than the TAB. In the treatment of exhaust gas which contains organic nitrogen compounds and/or hydrogen cyanide, the same difficulties occur, however, as with TAB: at relatively low temperatures the emission of primary harmful substances cannot be sufficiently lowered, while at temperatures which allow the emission of primary harmful substances to be lowered, the formation of oxides of nitrogen (NO,) increases. CAB is therefore not suitable for this use, either.
There is therefore a problem of providing a method for the treatment of exhaust gas, which allows emissions of harmful substances to be limited to the permissible range and which is suitable for the treatment of exhaust gas containing organic nitrogen compounds and/or hydrogen cyanide.
A particular object is to improve existing TAB-and/or CAB installations by simple measures.
According to one aspect of the present invention there is provided a method of reducing the concentration of harmful substances in an exhaust gas, comprising the steps of subjecting the gas to a thermal oxidizing, and/or catalytic oxidizing treatment in a first stage and subjecting the resulting gas stream to a catalytic treatment with the addition of ammonia in a subsequent stage.
It will thus be seen that the present method for the treatment of exhaust gas is a multiplestage method.
In the first stage, gas containing harmful substances is treated in a manner known per se, by a thermal oxidizing and/or catalytic oxidizing treatment.
In the case where the first stage is a thermal treatment, the first stage operates at a temperature of from 400 to 1000 C.; in the case where the first stage is a catalytic treatment, at a temperature of from 280 to 600 C., and in the case where the first stage is a combined thermal and catalytic treatment, at a temperature of from 400 to 600 C., in the thermal part of the stage and at a temperature of from 280 to 600 C. in the catalytic part of the stage.
The gas stream resulting from the first stage, which in the conventional method is regarded as the pure gas, is treated in the present method catalytically in a further or catalytic subsequent reaction stage (CSR stage) in the presence of ammonia.
The ammonia may be added directly into the further catalytic stage or into a duct connecting the first and said further stage.
In a preferred embodiment of the present method, the addition of ammonia is regulated according to the content of oxides of nitrogen (NO,) in the stream of gas resulting from the first stage. For this stage, accordingly, measuring and regulating devices are provided which are known per se. For example, for the continuous analysis of NOX, a partial stream may be branched off from the resulting gas stream, in which partial stream the NO, content is continuously determined by chemoluminescence analysis and this measured value is used to control the ammonia dose.
It has proved to be advantageous to add 0.3 to 3, preferably 0.5 to 2 parts by volume of ammonia per part by volume of oxides of nitrogen (NO,). In the case where the NO, contains high proportions of NO2 the amount of ammonia which is to be added will lie more in the upper region of the indicated range, whereas in the case where the NO, contains high proportions of
NO, a value may rather be selected from the lower region of the range.
In the further stage, the treatment with ammonia is preferably carried out at a temperature of from 130 to 320 C., more preferably from 150 to 250 C.
Oxidation catalysts, known per se, may be used as catalysts for the oxidizing treatment in the first stage, and also in the further stage. These may be used in all known forms, e.g. in the form of web-like or net-like structures or screens or as loose material of unformed or formed particles. Preferably, catalysts fixed on porous supports are used, in which the support is preferably constructed in the form of beads or extrudates or in the form of a honeycomb. The active component of the catalyst is based on a precious metal, preferably a precious metal of the platinum group, including osmium, iridium, ruthenium, rhodium and palladium as well as platinum itself, and/or vanadium. A catalyst is preferred which contains platinum and/or palladium as the precious metal component. Such catalysts are commercially available.
By the present method, exhaust gases can be treated which contain organic nitrogen compounds and/or hydrogen cyanide as primary harmful substances. In addition, in appropriate instances, other harmful substances containing carbon, hydrogen, and/or oxygen may be present in the exhaust gas. In particular, exhaust gases may be treated which contain one or more of the following nitrogen compounds:: -primary, secondary and tertiary aliphatic amines which contain alkyl radicals of for example 1 to 6 carbon atoms such as, for example, mono, di and tri methyl, ethyl, n-propyl and n-butyl amines, mono and di isopropyl, isobutyl and secbutyl amines and tert. butyl amine; -cycloalkyl amines, such as cyclohexyl amine, N-methyl and N,N-dimethyl cyclohexyl amines and dicyclohexyl amine; -di and poly amines, such as mono, di and-triethylene diamines; -cyciic amines, such as piperidine, morpholine, N-methyl and M-N-ethyl morpholine; -aromatic amines, such as aniline, toluidines, xylidines, aminophenols and benzyl amines; -nitriles, in particular aliphatic nitriles, such as aceto, propio and butyro nitriles, acrylonitrile and methacrylonitrile; -nitro compounds, including aliphatic nitro compounds, such as nitromethane, nitroethane and nitropropane and the nitrotoluenes;; -heterocycles containing nitrogen, such as pyridine and pyrrole; and -amide derivatives, such as, N,N-dimethylformamide.
Secondary harmful substances, such as, for example, formaldehyde or acetaldehyde, in particular carbon monoxide, oxides of nitrogen (NO,), ammonia and hydrogen cyanide, are produced from the primary harmful substances as a result of partial oxidation and/or decomposition reactions. The present method allows the content of secondary harmful substances in particular to be effectively limited.
In order to enable the invention to be more readily understood, reference will now be made to the accompanying drawing, which is a circuit diagram of one embodiment of an installation for the treatment of exhaust gas in accordance with the invention.
Referring now to the drawing, an exhaust gas which is to be purified in the installation there shown is passed through a duct 1 via heat exchanger means 2 to a first exhaust gas treatment stage 3. This exhaust gas treatment stage 3 may be a thermal treatment stage, a catalytic treatment stage or a combined thermal 3a and catalytic 3b treatment stage.
If the first treatment stage is a purely thermal stage (TAB) then the exhaust gas is purified by oxidation in a chamber of the thermal stage 3a with the supply of external energy. Preferably, fuel to supply this energy, e.g. a propane/air mixture, is supplied via a duct 4 and is burnt together with the exhaust gas in an open flame. The resulting gas stream containing primary and secondary harmful substances is passed to the heat exchanger 2 via a duct 5 and from there is passed to a further treatment stage 8 via a duct 5a.
If the first treatment stage is a purely catalytic stage (CAB), then the exhaust gas is passed via duct 1a to the catalytic stage in which a catalyst 6 is located, and from there it is passed to the further treatment stage 8 via a duct 7.
Preferably the first stage is a combined thermal/catalystic stage (TAB/CAB). In this case, the gas stream resulting from the thermal stage 3a is supplied to the catalytic stage 3b either via the duct 5 or directly via a duct 4a. The gas which has been subsequently treated catalytically (resulting gas) is passed via the duct 7/7a to the further stage 8 which is provided with a catalyst 9. Alternatively, the resulting gas stream may be passed to the heat exchanger 2 via duct 7/7b. The further stage 8 is dosed with ammonia which is introduced via duct 11.
Hbwever, it is also possible to dose ammonia into the duct 7a or 7b. The stream of pure gas emerging from the stage 8 is passed via a duct 12 to an exhaust gas flue (not shown).
Alternatively, if it has a sufficiently high heat content, the pure gas leaving the second stage 8 may be passed via duct 12a to a heat exchanger 10 and used for the additional exploitation of the use of the waste heat, e.g. supplying heat to a superheated steam duct 13.
By using the present method substantial advantages can be achieved in comparison with known methods.
In particular, primary harmful substances containing organically combined nitrogen and/or hydrogen cyanide can be removed from streams of exhaust air with reduced emission of oxides of nitrogen (NO,). Also intermediate products containing nitrogen, which occur as secondary harmful substances in conventional methods for the purification of exhaust air can be removed. The formation of oxides of nitrogen (NO,) from atmospheric nitrogen in using the TAB/CAB combination can be avoided because the combustion temperatures can be lowered. Existing thermal and/or catalytic exhaust gas combustion installations can easily and simply be adapted to amended legal requirements through the addition of a further treatment stage.Finally, the reduction of oxides of nitrogen (NO,) in the exhaust gas is not disturbed by atmospheric oxygen present in the exhaust gas.
The following Examples are intended to describe the method according to the invention in further detail, without restricting it in its scope.
The results shown in the following Tables 1 and 2 were obtained in an installation in which the first treatment was a combined thermal/catalytic stage (TAB/CAB). The exhaust gas was passed, in accordance with the installation shown in the drawing, via a duct 1a to a directly fired combustion chamber 3a, and from there via a duct 4a to the catalytic stage 3b. The resulting gas stream was passed via duct 7/7b for waste heat recovery via the heat exchanger 2 and passed to the further catalytic stage CSR stage 8. Both in the CAB stage 3a and also in the CSR stage 8 a commercially available oxidation catalyst of platinum base was used as catalyst (CAB stage 3a: Catalyst KCO-WK-220ST, Stage 8: Catalyst KCO-1934-K/M, Manufacture: Kali-Chemie AG).
For the analysis of the gas mixtures, samples were taken in each case before and after the individual method stages.
In Tables 1 and 2 the respective concentration of harmful substances (in percentage by volume) is shown as a function of the temperature T (measured in C. at the outlet of the combustion chamber). The composition is related therein either to the carbon combined in the primary harmful substance (C-balance) or to nitrogen (N-balance).
Other abbreviations which are indicated have the following meanings:
S = harmful substance;
C-IP =organic intermediate products free of
nitrogen;
R = molar ratio NH/N0,; C concentration of primary harmful
substance;
Th = throughput.
From the results shown, the reduction in primary or secondary harmful substances by using the present method can be seen clearly.
Corresponding experiments with hydrogen cyanide, 2-nitrotoluene and acrylonitrile as primary harmful substances produced comparably good results.
Table 1: n-Propylamine as primary harmful substance a) C-balance
TAB TAB + CAB TAB + CAB + CSR S C-IP CO HCN CO2 S C-IP CO HCN CO2 S C-IP CO HCN CO2 400 50 21 10 2 17 6 0 0 0 94 2 0 0 0 98 450 44 17 14 4 21 4 0 0 0 96 500 38 9 21 7 25 3 0 0 0 97 550 31 0 34 10 25 2 0 0 0 98 600 21 0 35 10 34 2 0 0 0 98 b) N-balanca
TAB TAB + CAB TAB + CAB + CSR S HCN NH3 NO2 N2 S HCN NH3 NO2 N2 S HCN NH3 NO2 N2 400 50 7 0 3 40 6 0 0 51 43 2 0 0 0 95 450 44 11 0 5 40 4 0 0 57 39 500 38 20 0 9 33 3 0 0 59 38 550 31 32 7 12 18 2 0 0 61 37 600 21 30 11 15 23 2 0 0 60 38 c = 750 pm, Th = 74,5 Nm /h, R = 1,4 Table 2::
Aniline as primary harmful substance a) C-balance
TAB TAB + CAB TAB + CAB + CSR S C-IP CO HCN CO2 S C-IP CO HCN CO2 S C-IP CO HCN CO2 420 59 10 11 0 20 19 0 0 0 81 8 0 0 0 92 480 45 5 29 1 20 10 0 0 0 90 550 25 0 50 1 24 10 0 0 0 90 600 17 0 45 4 34 5 0 0 0 95 b) N-balance
TAB TAB + CAB TAB + CAB + CSR S HCN NH3 NO2 N2 S HCN NH3 NO2 N2 S HCN NH3 NO2 N2 420 59 3 0 21 17 19 0 0 70 11 8 0 0 21 71 480 45 4 3 45 3 10 0 0 90 0 550 25 6 14 55 0 10 0 0 90 0 600 17 21 7 55 0 5 0 0 95 0 c = 220 pm, Th = 78 Nm /h, R = 2,5
Claims (15)
1. A method of reducing the concentration of harmful substances in an exhaust gas, comprising the steps of subjecting the gas to a thermal oxidizing and/or catalytic oxidizing treatment in a first stage and subjecting the resulting gas stream to catalytic treatment with the addition of ammonia in a subsequent stage.
2. The method of Claim 1, wherein the thermal oxidizing treatment is carried out at a temperature of from 400 to 1000 C.
3. The method of Claim 1 or 2, wherein the catalytic oxidizing treatment is carried out at a temperature of from 280 to 600"C.
4. The method of any one of Claims 1 to 3, wherein the first stage comprises a thermal oxidizing treatment carried out at a temperature of from 400 to 6000C and a catalytic oxidizing treatment carried out at a temperature of from 280 to 600 C.
5. The method of any one of Claim 1 or 4, wherein the catalytic treatment with ammonia in the subsequent stage is carried out at a temperature of from 130 to 320 C.
6. The method of Claim 5, wherein said temperature is from 150 to 250 C.
7. The method of any one of Claims 1 to 6, wherein the addition of ammonia is regulated according to the content of oxides of nitrogen (NO,) in the resulting gas stream.
8. The method of any one of Claims 1 to 7, wherein from 0.3 to 3 parts by volume of ammonia is added per part by volume of oxides of nitrogen.
9. The method of any one of Claims 1 to 8, wherein from 0.5 to 2 parts by volume of ammonia is added per part by volume of oxides of nitrogen.
10. The method of any one of Claims 1 to 9, wherein the catalyst used in the catalytic oxidizing treatment and/or in the catalytic treatment with ammonia comprises a precious metal and/or vanadium.
11. The method of Claim 10, wherein said precious metal is selected from osmium, iridium, ruthenium, rhodium, palladium and platinum.
12. A method of reducing the concentration of harmful substances in an exhaust gas, comprising the steps of subjecting the gas in a first stage to a thermal oxidizing treatment at a temperature of from 400 to 100 C. and/or to a catalytic oxidizing treatment at a temperature of from 280 to 600 C. over a catalyst comprising a precious metal and/or vanadium, analysing the resulting gas stream to determine the content therein of oxides of nitrogen, adding ammonia to the resulting gas stream in an amount of from 0.3 to 3 part by volume of ammonia per part by volume of oxides of nitrogen, and subjecting the resulting gas stream and said ammonia in a subsequent stage to a catalytic treatment over a catalyst comprising a precious metal and/or vanadium.
13. A method of reducing the concentration of harmful substances in an exhaust gas substantially as hereinbefore described with reference to the accompanying drawing and/or in the foregoing Examples.
14. A method of improving an existing exhaust gas treatment installation, such installation comprising a stage for the thermal oxidizing and/or catalytic oxidizing treatment of said gas, comprising the step of adding a further catalytic stage in which the exhaust gas can be treated with ammonia whereby the installation becomes capable of treating exhaust gas which contains organic nitrogen compounds.
15. An installation for the treatment of exhaust gas, comprising a first stage for subjecting the gas to a thermal oxidizing or catalytic oxidizing treatment, and a subsequent catalytic stage connectable to a source of ammonia for subjecting the resulting gas from the first stage to a catalytic treatment with ammonia.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19843442927 DE3442927A1 (en) | 1984-11-24 | 1984-11-24 | EXHAUST GAS TREATMENT METHOD |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8523742D0 GB8523742D0 (en) | 1985-10-30 |
| GB2167396A true GB2167396A (en) | 1986-05-29 |
| GB2167396B GB2167396B (en) | 1988-06-02 |
Family
ID=6251082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08523742A Expired GB2167396B (en) | 1984-11-24 | 1985-09-26 | Method for the treatment of exhaust gas |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS61197024A (en) |
| BE (1) | BE903702A (en) |
| DE (1) | DE3442927A1 (en) |
| ES (1) | ES8701511A1 (en) |
| FR (1) | FR2573673A1 (en) |
| GB (1) | GB2167396B (en) |
| IT (1) | IT1185416B (en) |
| NL (1) | NL8502935A (en) |
| SE (1) | SE8505468L (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0800855A1 (en) * | 1996-04-11 | 1997-10-15 | Sara Lee/DE N.V. | Method for the catalytic oxidation of off-gases |
| US6187275B1 (en) * | 1995-12-08 | 2001-02-13 | Goldendale Aluminum Company | Recovery of AlF3 from spent potliner |
| US6248302B1 (en) | 2000-02-04 | 2001-06-19 | Goldendale Aluminum Company | Process for treating red mud to recover metal values therefrom |
| US6468483B2 (en) | 2000-02-04 | 2002-10-22 | Goldendale Aluminum Company | Process for treating alumina-bearing ores to recover metal values therefrom |
| WO2009050323A1 (en) * | 2007-10-19 | 2009-04-23 | Ecocat Oy | Removal of ammonia from fluids |
| CN114811624A (en) * | 2021-01-22 | 2022-07-29 | 中国科学院大学 | DMF-containing waste gas purification and collaborative production N 2 Method of O |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1282185A (en) * | 1969-09-22 | 1972-07-19 | Ford Motor Co | Internal combustion engine having exhaust gas treatment |
| GB1480657A (en) * | 1974-04-11 | 1977-07-20 | Sumitomo Chemical Co | Process for concurrently treating process waste waters and flue gases from ammonia synthesis |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3838193A (en) * | 1971-03-13 | 1974-09-24 | Kawasaki Heavy Ind Ltd | Method of treating nitrogen oxide generating substances by combustion |
| JPS513365A (en) * | 1974-06-27 | 1976-01-12 | Ishikawajima Harima Heavy Ind | Haigasuchuno chitsusosankabutsuno jokyohoho |
| JPS53108065A (en) * | 1977-02-09 | 1978-09-20 | Kurita Water Ind Ltd | Treating method for gas containing ammonia |
| JPS53102866A (en) * | 1977-02-21 | 1978-09-07 | Shokubai Kasei Kogyo Kk | Treating method for waste gas comtaining ammonia |
| JPS53123367A (en) * | 1977-04-04 | 1978-10-27 | Sumitomo Heavy Ind Ltd | Exhaust gas treating method |
| US4351811A (en) * | 1977-07-20 | 1982-09-28 | Hitachi, Ltd. | Process for reducing an eliminating nitrogen oxides in an exhaust gas |
| JPS5829125B2 (en) * | 1979-11-05 | 1983-06-21 | トヨタ自動車株式会社 | Purification equipment for ammonia or ammonia-containing organic mixed gas |
-
1984
- 1984-11-24 DE DE19843442927 patent/DE3442927A1/en not_active Withdrawn
-
1985
- 1985-09-26 GB GB08523742A patent/GB2167396B/en not_active Expired
- 1985-10-11 IT IT22443/85A patent/IT1185416B/en active
- 1985-10-28 NL NL8502935A patent/NL8502935A/en not_active Application Discontinuation
- 1985-11-18 FR FR8517010A patent/FR2573673A1/en active Pending
- 1985-11-19 SE SE8505468A patent/SE8505468L/en not_active Application Discontinuation
- 1985-11-22 ES ES549177A patent/ES8701511A1/en not_active Expired
- 1985-11-22 BE BE0/215906A patent/BE903702A/en not_active IP Right Cessation
- 1985-11-25 JP JP60262726A patent/JPS61197024A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1282185A (en) * | 1969-09-22 | 1972-07-19 | Ford Motor Co | Internal combustion engine having exhaust gas treatment |
| GB1480657A (en) * | 1974-04-11 | 1977-07-20 | Sumitomo Chemical Co | Process for concurrently treating process waste waters and flue gases from ammonia synthesis |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6187275B1 (en) * | 1995-12-08 | 2001-02-13 | Goldendale Aluminum Company | Recovery of AlF3 from spent potliner |
| EP0800855A1 (en) * | 1996-04-11 | 1997-10-15 | Sara Lee/DE N.V. | Method for the catalytic oxidation of off-gases |
| NL1002847C2 (en) * | 1996-04-11 | 1997-10-15 | Sara Lee De Nv | Process for the catalytic combustion of waste gases. |
| US6248302B1 (en) | 2000-02-04 | 2001-06-19 | Goldendale Aluminum Company | Process for treating red mud to recover metal values therefrom |
| US6468483B2 (en) | 2000-02-04 | 2002-10-22 | Goldendale Aluminum Company | Process for treating alumina-bearing ores to recover metal values therefrom |
| WO2009050323A1 (en) * | 2007-10-19 | 2009-04-23 | Ecocat Oy | Removal of ammonia from fluids |
| US8337793B2 (en) | 2007-10-19 | 2012-12-25 | Ecocat Oy | Removal of ammonia from fluids |
| CN114811624A (en) * | 2021-01-22 | 2022-07-29 | 中国科学院大学 | DMF-containing waste gas purification and collaborative production N 2 Method of O |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61197024A (en) | 1986-09-01 |
| BE903702A (en) | 1986-03-14 |
| NL8502935A (en) | 1986-06-16 |
| GB2167396B (en) | 1988-06-02 |
| ES8701511A1 (en) | 1986-12-01 |
| IT1185416B (en) | 1987-11-12 |
| DE3442927A1 (en) | 1986-06-05 |
| GB8523742D0 (en) | 1985-10-30 |
| SE8505468D0 (en) | 1985-11-19 |
| SE8505468L (en) | 1986-05-25 |
| FR2573673A1 (en) | 1986-05-30 |
| IT8522443A0 (en) | 1985-10-11 |
| ES549177A0 (en) | 1986-12-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |