CA2122321A1 - Process for purifying combustion plant flue gases which contain oxides of nitrogen and sulphur - Google Patents
Process for purifying combustion plant flue gases which contain oxides of nitrogen and sulphurInfo
- Publication number
- CA2122321A1 CA2122321A1 CA002122321A CA2122321A CA2122321A1 CA 2122321 A1 CA2122321 A1 CA 2122321A1 CA 002122321 A CA002122321 A CA 002122321A CA 2122321 A CA2122321 A CA 2122321A CA 2122321 A1 CA2122321 A1 CA 2122321A1
- Authority
- CA
- Canada
- Prior art keywords
- sulphuric acid
- stage
- sulphur
- counter
- nitrogen
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/88—Concentration of sulfuric acid
-
- 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
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/507—Sulfur oxides by treating the gases with other liquids
-
- 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
- B01D53/8637—Simultaneously removing sulfur oxides and nitrogen oxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
- C01B17/76—Preparation by contact processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biomedical Technology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Treating Waste Gases (AREA)
- Gas Separation By Absorption (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention relates to an advantageous further development of a process for purifying flue gases which contain oxides of nitrogen and sulphur from a combustion plant by selective catalytic reduction of the nitrogen oxides, subsequent catalytic oxidation of sulphuric dioxide with oxygen to give sulphur trioxide and washing the sulphur trioxide out of the flue gases as aqueous sulphuric acid. The further development according to the invention relates to concentrating the aqueous sulphuric acid to more than 95 wt. % strength sulphuric acid.
The invention relates to an advantageous further development of a process for purifying flue gases which contain oxides of nitrogen and sulphur from a combustion plant by selective catalytic reduction of the nitrogen oxides, subsequent catalytic oxidation of sulphuric dioxide with oxygen to give sulphur trioxide and washing the sulphur trioxide out of the flue gases as aqueous sulphuric acid. The further development according to the invention relates to concentrating the aqueous sulphuric acid to more than 95 wt. % strength sulphuric acid.
Description
21223~
The invention relates to an advantageous further development of a process for purifying combustion plant flue gases which contain oxides of nitrogen and sulphur by selective catalytic reduction of the nitrogen oxides, subsequent catalytic -~
oxidation or sulphur dioxide with oxygen to give sulphur trioxide and washing the sulphur trioxide out of the flue ~ -gases as aqueous sulphuric acid. -A process of this type is described, for example, in DE 36 01 ;~
378 and is known as the Desonox process in the flue gas purification industry. In the twocstage Desonox process, in ~
the first stage the nitrogen oxides are converted to nitrogen ~ ; -and water at elevated temperature on a catalyst with the -~
addition of a gaseous reducing agent (ammonia, for example) ~ -in the presence of the oxygen which is still contained in the -flue gas. This process is known as selective catalytic reduction in the industry. In the immediately subsequent ~ -second stage, the flue gas, which still contains sulphur dioxide, oxygen and optionally carbon monoxide and hydrocarbons, is passed over an oxidizing catalyst on which sulphur dioxide is converted to sulphur trioxide in high ;~
yields. Carbon monoxide, hydrocarbons and optionally ~
reducing agent which was not consumed in the reducing stage, -- .
are simultaneously transformed into carbon dioxide, nitrogen and water. -~
, ., .:
After cooling the flue gas, sulphur trioxide is hydrated in a siingle or multi-stage sulphuric acid scrubber by contact with dilute sulphuric acid and is removed as sulphuric acid with the highest possible percentage strength. ~ -: : , ~ "~ ~,' ` 212232~ 1 The flue gas temperatures in the two catalytic stages are between about 250 and 550C. The temperature must be lowered to 40 to 130-C for hydration of the sulphur trioxide. This takes place in a heat exchanger with simultaneous heating of the fresh air required for the combustion plant to temperatures of up to 300-C.
Basically, any catalysts which are suitable for the selective reduction of nitrogen oxides may be used as reducing catalysts in this process. Examples of these are catalysts based on mixtures of oxides of titanium, tungsten, vanadium and molybdenum (DE-PS 24 58 888, DE-PS 39 06 136) or catalysts consisting of natural or synthetic aluminum silicates, e.g. zeolites (DE-PS 38 41 990) or catalysts which contain noble metals from the platinum group. Any catalyst systems which are commonly used for oxidizing sulphur dioxide may al80 be used in this case. Examples of these are the systems listed in Gmelin, Handbuch der Anorg. Chemie, vol. 9, part A, pages 320 ff. (1975), e.g. platinum or vanadium pentoxide or catalysts which contain iron oxide and the catalysts described in DE-PS 40 18 324.
`:
A particular feature of this type of flue gas purification process is removal of the sulphur dioxide contained in the flue gas in the form of sulphuric acid, which can be mar~eted as a valuable product. I ;
However, it is a disadvantage that the sulphuric acid ` `~
produced in the Desonox process has a concentration of only `
The invention relates to an advantageous further development of a process for purifying combustion plant flue gases which contain oxides of nitrogen and sulphur by selective catalytic reduction of the nitrogen oxides, subsequent catalytic -~
oxidation or sulphur dioxide with oxygen to give sulphur trioxide and washing the sulphur trioxide out of the flue ~ -gases as aqueous sulphuric acid. -A process of this type is described, for example, in DE 36 01 ;~
378 and is known as the Desonox process in the flue gas purification industry. In the twocstage Desonox process, in ~
the first stage the nitrogen oxides are converted to nitrogen ~ ; -and water at elevated temperature on a catalyst with the -~
addition of a gaseous reducing agent (ammonia, for example) ~ -in the presence of the oxygen which is still contained in the -flue gas. This process is known as selective catalytic reduction in the industry. In the immediately subsequent ~ -second stage, the flue gas, which still contains sulphur dioxide, oxygen and optionally carbon monoxide and hydrocarbons, is passed over an oxidizing catalyst on which sulphur dioxide is converted to sulphur trioxide in high ;~
yields. Carbon monoxide, hydrocarbons and optionally ~
reducing agent which was not consumed in the reducing stage, -- .
are simultaneously transformed into carbon dioxide, nitrogen and water. -~
, ., .:
After cooling the flue gas, sulphur trioxide is hydrated in a siingle or multi-stage sulphuric acid scrubber by contact with dilute sulphuric acid and is removed as sulphuric acid with the highest possible percentage strength. ~ -: : , ~ "~ ~,' ` 212232~ 1 The flue gas temperatures in the two catalytic stages are between about 250 and 550C. The temperature must be lowered to 40 to 130-C for hydration of the sulphur trioxide. This takes place in a heat exchanger with simultaneous heating of the fresh air required for the combustion plant to temperatures of up to 300-C.
Basically, any catalysts which are suitable for the selective reduction of nitrogen oxides may be used as reducing catalysts in this process. Examples of these are catalysts based on mixtures of oxides of titanium, tungsten, vanadium and molybdenum (DE-PS 24 58 888, DE-PS 39 06 136) or catalysts consisting of natural or synthetic aluminum silicates, e.g. zeolites (DE-PS 38 41 990) or catalysts which contain noble metals from the platinum group. Any catalyst systems which are commonly used for oxidizing sulphur dioxide may al80 be used in this case. Examples of these are the systems listed in Gmelin, Handbuch der Anorg. Chemie, vol. 9, part A, pages 320 ff. (1975), e.g. platinum or vanadium pentoxide or catalysts which contain iron oxide and the catalysts described in DE-PS 40 18 324.
`:
A particular feature of this type of flue gas purification process is removal of the sulphur dioxide contained in the flue gas in the form of sulphuric acid, which can be mar~eted as a valuable product. I ;
However, it is a disadvantage that the sulphuric acid ` `~
produced in the Desonox process has a concentration of only `
2 ~
'~ ~
- 212~321 ~ -!
about 70 to 80 wt. % and thus cannot fetch a satisfactory ~ -market price. --The present invention provides a further development of the Desonox process which supplies sulphuric acid concentrated to ~ :~
at least 95 wt. %.
':."' ,-.''~
More particularly, the present process is characterized in ~ -that the 70 to 80 wt. % sulphuric acid from the sulphuric ~ -acid scrubber is concentrated to more than 95 wt. % by counter-current desorption of water using a hot gas and the vent gas from counter-current desorption is also fed to the sulphuric acid scrubber to remove sulphuric acid aerosols.
~, ' ~''.'.
The hot gas required for counter-current desorption can be ;
withdrawn as a partial stream from the fresh air for the combustion plant which is heated by the heat exchanger. The -partial stream required for desorption comprises only about 5S of the total fresh air supplied to the combustion plant.
In another advantageous form of the process, the hot gas re~uired for counter-current desorption is withdrawn from the :
flue gas stream after the oxidizing stage.
The desorption column required for counter-current desorption may be designed as a packed column with 3 - 4 separation stagçs, any other appropriate technology, however, may also ~ ~;
be used. The sulphuric acid is sprayed into this desorption column from above so that the droplets fall downwards under gravity into a type of sump. ~ -"~
2 1 2 2 3 2 ~
The hot fresh air or hot flue gas is blown into the lower region and passed upwards in a counter-current to the sulphuric acid. The water contained in the sulphuric acid is thus desorbed and is discharged with the air stream. A
special advantage of the process according to the invention is the very cost-effective incorporation of this concentrating stage into the flue gas purification process.
The desorption air is taken from either the fresh air stream intended for the combustion plant or from the flue gas. The vent gas from the desorption column may be returned to the flue gas and purified with the flue gas. Therefore no - additional heating, cooling or purification equipment is required.
A temperature of ca. 150 to 200-C has proven to be suitable for the hot gases required for desorption. If heat-resistant materials are used for constructing the apparatus for the desorption column, then the gas required for desorbing the water can also be introduced at a higher temperature (e.g.
250 - 300-C). In that case, however, larger amounts of sulphuric acid aerosols are also discharged with the vent gas and these must be washed out again in the sulphuric acid scrubber.
.' ' .:.,~
Depending on the temperature of the amount of warmed fresh air,lthe amount of air required for desorption is withdrawn completely or partly from the warmed fresh air stream, the remainder coming from the still unheated stream of fresh air or optionally from a compressed air unit. The two air --.
- 2122321 :: :~
...: -, streams can be regulated via a control valve so that a permanently constant desorption air temperature can be maintained. Flue gas with the appropriate temperature and pressure may also be used instead of the fresh air.
The vent gas from the desorption column which possibly - -contains sulphuric acid aerosols is fed to the flue gas before the sulphuric acid scrubber and is purified along the subseguent flue gas route.
~0 .' "' ~ ' Figure l shows a process scheme for a specific example of the process according to the invention. The reference numbers (1) to (lO) designate the components of the Desonox proicess ~-known from the prior art: -(l) combustion plant with steam generator (2) electrostatic filter for separating dust (3) catalytic reactor (4) reducing catalyst (5) oxidizing catalyst (6) heat-exchanger in the form of a tubular air pre-heater ~ ~ -(7) sulphuric acid scrubber `~
'~ ~
- 212~321 ~ -!
about 70 to 80 wt. % and thus cannot fetch a satisfactory ~ -market price. --The present invention provides a further development of the Desonox process which supplies sulphuric acid concentrated to ~ :~
at least 95 wt. %.
':."' ,-.''~
More particularly, the present process is characterized in ~ -that the 70 to 80 wt. % sulphuric acid from the sulphuric ~ -acid scrubber is concentrated to more than 95 wt. % by counter-current desorption of water using a hot gas and the vent gas from counter-current desorption is also fed to the sulphuric acid scrubber to remove sulphuric acid aerosols.
~, ' ~''.'.
The hot gas required for counter-current desorption can be ;
withdrawn as a partial stream from the fresh air for the combustion plant which is heated by the heat exchanger. The -partial stream required for desorption comprises only about 5S of the total fresh air supplied to the combustion plant.
In another advantageous form of the process, the hot gas re~uired for counter-current desorption is withdrawn from the :
flue gas stream after the oxidizing stage.
The desorption column required for counter-current desorption may be designed as a packed column with 3 - 4 separation stagçs, any other appropriate technology, however, may also ~ ~;
be used. The sulphuric acid is sprayed into this desorption column from above so that the droplets fall downwards under gravity into a type of sump. ~ -"~
2 1 2 2 3 2 ~
The hot fresh air or hot flue gas is blown into the lower region and passed upwards in a counter-current to the sulphuric acid. The water contained in the sulphuric acid is thus desorbed and is discharged with the air stream. A
special advantage of the process according to the invention is the very cost-effective incorporation of this concentrating stage into the flue gas purification process.
The desorption air is taken from either the fresh air stream intended for the combustion plant or from the flue gas. The vent gas from the desorption column may be returned to the flue gas and purified with the flue gas. Therefore no - additional heating, cooling or purification equipment is required.
A temperature of ca. 150 to 200-C has proven to be suitable for the hot gases required for desorption. If heat-resistant materials are used for constructing the apparatus for the desorption column, then the gas required for desorbing the water can also be introduced at a higher temperature (e.g.
250 - 300-C). In that case, however, larger amounts of sulphuric acid aerosols are also discharged with the vent gas and these must be washed out again in the sulphuric acid scrubber.
.' ' .:.,~
Depending on the temperature of the amount of warmed fresh air,lthe amount of air required for desorption is withdrawn completely or partly from the warmed fresh air stream, the remainder coming from the still unheated stream of fresh air or optionally from a compressed air unit. The two air --.
- 2122321 :: :~
...: -, streams can be regulated via a control valve so that a permanently constant desorption air temperature can be maintained. Flue gas with the appropriate temperature and pressure may also be used instead of the fresh air.
The vent gas from the desorption column which possibly - -contains sulphuric acid aerosols is fed to the flue gas before the sulphuric acid scrubber and is purified along the subseguent flue gas route.
~0 .' "' ~ ' Figure l shows a process scheme for a specific example of the process according to the invention. The reference numbers (1) to (lO) designate the components of the Desonox proicess ~-known from the prior art: -(l) combustion plant with steam generator (2) electrostatic filter for separating dust (3) catalytic reactor (4) reducing catalyst (5) oxidizing catalyst (6) heat-exchanger in the form of a tubular air pre-heater ~ ~ -(7) sulphuric acid scrubber `~
(8) droplet separator (9) fresh air inlet ` -(10) warmed fresh air ~
.
Reference numbers (11) to (18) label the components required for concentrating the sulphuric acid according to the invention.
212232 1 !
The fresh air for the combustion plant is passed through the heat-exchanger (6) designed as a tubular air pre-heater in a counter-current using an air blower, as a cooling medium for the hot flue gas and is thereby heated to ca. 300C.
A partial stream is branched off from the heated fresh air (10), at (11), as desorption air. In order to adjust the desorption temperature to about 200-C, approximately 37 vol.
% of non-pre-heated fresh air (12) is admixed with the desorption air stream at (13) by means of a temperature-controlled mixer. The thus adjusted desorption air passes from below at (14) into the desorption column (15) and, in a counter-current, desorbs water from the approximately 70 wt %
strength sulphuric acid which is sprayed from above at (17) into the desorption column. The concentrated, approximately 95 wt. % strength sulphuric acid is withdrawn at the bottom of the desorption column and temporarily stored in a production tank (18). The vent gas from the desorption column is mixed with the flue gas stream at (16).
~
To concentrate 70 wt. % strength sulphuric acid 95 wt. % -strength sulphuric acid, 1200 Nm3/h of desorption air at 200-C are required per 100 kg of 95 wt. % sulphuric acid.
The vent gas from the desorption column (1260 Nm3/h per 100 kg of 95 wt. % H2S04) contains ca. 5 vol. % of water and 0.1 vol.,ppm of sulphuric acid. The temperature of the vent gas is lOO~C. It can be added to the flue gas either before the heat-exchanger or before the sulphuric acid scrubber. The f`~ 2122321 sulphuric acid draining into production tank (18) has a concentration of 95 wt % at a temperature of 160C. It i8 .-less corrosive than 70 wt. % strength sulphuric acid.
Therefore savings can be made with respect to the subsequent units due to lower demands on the quality of the materials. ~- -' . -. '' The following table gives a few calculated examples for concentrating sulphuric acid with different concentrations in process according to the invention.
~,, "~
Example No. 1 2 3 4 fro~ H2S04 conc.: 70 wt.% 60 wt.~ 40 wt.~ 40 wt.
to ~2So4 conc-s 95 wt.~ 96.5 wt.~ 95.5 wt.~ 95.5 wt.
15 ~r ~nlet temp.: 200-C 200-C 200-C 250-C
a ount of a~r: 12 ~3/kg 13.2 m3/kg 19.7 m3/kg 14 5 ~3/kg H2~04 temp.s 160-C 172-C 167-C l90-C
V nt 9~- temp.s 100-C 86-C 70-C 73-C
Cc~oent~ t-ge l-~t-ge 2-~tage 2-~tage ' ''::', ~' Thus sulphuric acid may also be concentrated up from more dilute solutions, e.g. 40 wt. %, to 95 wt. %. Although this i8 theoretically possible, there are reservations as to the -25 wider applicability of the process. Here, the greatly incr,eased expenditure on going to a two-stage division of the ; ~
column, with separate air supplies to the columns, is -disadvantageous.
"'.','~
.
Reference numbers (11) to (18) label the components required for concentrating the sulphuric acid according to the invention.
212232 1 !
The fresh air for the combustion plant is passed through the heat-exchanger (6) designed as a tubular air pre-heater in a counter-current using an air blower, as a cooling medium for the hot flue gas and is thereby heated to ca. 300C.
A partial stream is branched off from the heated fresh air (10), at (11), as desorption air. In order to adjust the desorption temperature to about 200-C, approximately 37 vol.
% of non-pre-heated fresh air (12) is admixed with the desorption air stream at (13) by means of a temperature-controlled mixer. The thus adjusted desorption air passes from below at (14) into the desorption column (15) and, in a counter-current, desorbs water from the approximately 70 wt %
strength sulphuric acid which is sprayed from above at (17) into the desorption column. The concentrated, approximately 95 wt. % strength sulphuric acid is withdrawn at the bottom of the desorption column and temporarily stored in a production tank (18). The vent gas from the desorption column is mixed with the flue gas stream at (16).
~
To concentrate 70 wt. % strength sulphuric acid 95 wt. % -strength sulphuric acid, 1200 Nm3/h of desorption air at 200-C are required per 100 kg of 95 wt. % sulphuric acid.
The vent gas from the desorption column (1260 Nm3/h per 100 kg of 95 wt. % H2S04) contains ca. 5 vol. % of water and 0.1 vol.,ppm of sulphuric acid. The temperature of the vent gas is lOO~C. It can be added to the flue gas either before the heat-exchanger or before the sulphuric acid scrubber. The f`~ 2122321 sulphuric acid draining into production tank (18) has a concentration of 95 wt % at a temperature of 160C. It i8 .-less corrosive than 70 wt. % strength sulphuric acid.
Therefore savings can be made with respect to the subsequent units due to lower demands on the quality of the materials. ~- -' . -. '' The following table gives a few calculated examples for concentrating sulphuric acid with different concentrations in process according to the invention.
~,, "~
Example No. 1 2 3 4 fro~ H2S04 conc.: 70 wt.% 60 wt.~ 40 wt.~ 40 wt.
to ~2So4 conc-s 95 wt.~ 96.5 wt.~ 95.5 wt.~ 95.5 wt.
15 ~r ~nlet temp.: 200-C 200-C 200-C 250-C
a ount of a~r: 12 ~3/kg 13.2 m3/kg 19.7 m3/kg 14 5 ~3/kg H2~04 temp.s 160-C 172-C 167-C l90-C
V nt 9~- temp.s 100-C 86-C 70-C 73-C
Cc~oent~ t-ge l-~t-ge 2-~tage 2-~tage ' ''::', ~' Thus sulphuric acid may also be concentrated up from more dilute solutions, e.g. 40 wt. %, to 95 wt. %. Although this i8 theoretically possible, there are reservations as to the -25 wider applicability of the process. Here, the greatly incr,eased expenditure on going to a two-stage division of the ; ~
column, with separate air supplies to the columns, is -disadvantageous.
"'.','~
Claims (4)
1. A process for purifying flue gases which contain oxides of nitrogen and sulphur from a combustion plant in a two-stage process by catalytic reduction of the nitrogen oxides in the first stage, with the addition of a reducing agent, and subsequent catalytic oxidation of carbon monoxide still contained in the flue gas, hydrocarbons and optionally reducing agent which was not consumed in the reducing stage, to give nitrogen, water and carbon dioxide and oxidation of the sulphur dioxide contained in the flue gas to give sulphur trioxide in the second stage, at temperatures of 250 to 550°C; cooling of the treated flue gas to 110 to 140°C in a heat exchanger with simultaneous heating of the fresh air for the combustion plant to temperatures of 140 to 300°C and hydration of the sulphur trioxide in a single or multi-stage sulphuric acid scrubber with aqueous sulphuric acid at temperatures of 40 to 130°C to give 70 to 80 wt. % strength sulphuric-acid, characterized in that, the thus obtained 70 to 80 wt. % strength sulphuric acid is concentrated to more than 95 wt. % by counter-current desorption of water using a hot gas and the vent gas from counter-current desorption is optionally fed to the sulphuric acid scrubber to remove sulphuric acid aerosols.
!
!
2. A process according to Claim 1, characterized in that the hot gas required for counter-current desorption is taken from the heated fresh air for the combustion plant.
3. A process according to Claim 1, characterized in that the hot gas required for counter-current desorption is taken from the flue gas stream after the oxidation stage.
4. A process according to Claims 2 or 3, characterized in that the temperature of the hot gas required for counter-current desorption is adjusted to a value in the range between 150 and 250°C by admixing fresh air.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4313897A DE4313897C1 (en) | 1993-04-28 | 1993-04-28 | Process for cleaning oxides of nitrogen and sulfur containing flue gases from incineration plants |
| DEP4313897.7 | 1993-04-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2122321A1 true CA2122321A1 (en) | 1994-10-29 |
Family
ID=6486587
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002122321A Abandoned CA2122321A1 (en) | 1993-04-28 | 1994-04-27 | Process for purifying combustion plant flue gases which contain oxides of nitrogen and sulphur |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0622106A1 (en) |
| JP (1) | JPH06319955A (en) |
| CA (1) | CA2122321A1 (en) |
| DE (1) | DE4313897C1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104707475A (en) * | 2015-04-03 | 2015-06-17 | 中南大学 | Flue gas treatment method for simultaneous low-temperature photocatalytic self oxidation reduction, desulfurization and denitrification |
| CN106215660A (en) * | 2016-08-25 | 2016-12-14 | 灵宝金源晨光有色矿冶有限公司 | SO in a kind of recovery tail gas2system |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5554350A (en) * | 1994-12-15 | 1996-09-10 | Combustion Engineering, Inc. | Air pollution control and heat recovery system and process for coal fired power plant |
| DE19810758C1 (en) * | 1998-03-12 | 1999-06-24 | Carola Poetzscher Gmbh & Co Kg | Smoke gas cleansing unit |
| CN1111078C (en) * | 1999-12-30 | 2003-06-11 | 赵善茂 | Complex utilization method for boiler fume |
| CN105311955B (en) * | 2015-11-05 | 2017-09-15 | 张文国 | A kind of industrial refuse cracking incineration tail gas depickling processing method |
| JP7316146B2 (en) * | 2019-08-14 | 2023-07-27 | 日本管機工業株式会社 | Dilute sulfuric acid production apparatus and dilute sulfuric acid production method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU85454A1 (en) * | 1984-07-06 | 1985-09-12 | Euratom | METHOD AND DEVICE FOR REMOVING SULFUR DIOXIDE FROM HOT EXHAUST GASES |
| EP0191725A3 (en) * | 1985-01-16 | 1989-11-02 | Ciba-Geigy Ag | Process for separating sulfur dioxyde from gases and for obtaining concentrated sulfuric acid |
| DE3601378A1 (en) * | 1986-01-18 | 1987-07-23 | Degussa | METHOD FOR PURIFYING OXIDES OF NITROGEN AND EXHAUST GASES CONTAINING SULFUR FROM COMBUSTION PLANTS |
| DE3624461A1 (en) * | 1986-07-19 | 1988-01-28 | Metallgesellschaft Ag | METHOD FOR PURIFYING SMOKE GASES |
| DE3629765A1 (en) * | 1986-09-02 | 1988-03-03 | Bayer Ag | METHOD FOR PURIFYING EXHAUST GASES |
| DE3744031A1 (en) * | 1987-12-24 | 1989-07-06 | Metallgesellschaft Ag | METHOD FOR PURIFYING SMOKE GASES |
-
1993
- 1993-04-28 DE DE4313897A patent/DE4313897C1/en not_active Expired - Fee Related
-
1994
- 1994-03-08 EP EP94103488A patent/EP0622106A1/en not_active Withdrawn
- 1994-04-25 JP JP6086346A patent/JPH06319955A/en active Pending
- 1994-04-27 CA CA002122321A patent/CA2122321A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104707475A (en) * | 2015-04-03 | 2015-06-17 | 中南大学 | Flue gas treatment method for simultaneous low-temperature photocatalytic self oxidation reduction, desulfurization and denitrification |
| CN106215660A (en) * | 2016-08-25 | 2016-12-14 | 灵宝金源晨光有色矿冶有限公司 | SO in a kind of recovery tail gas2system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4313897C1 (en) | 1995-03-02 |
| EP0622106A1 (en) | 1994-11-02 |
| JPH06319955A (en) | 1994-11-22 |
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