CA2343782A1 - Method for removing nitrogen oxides from nitrosyl sulphuric acid - Google Patents
Method for removing nitrogen oxides from nitrosyl sulphuric acid Download PDFInfo
- Publication number
- CA2343782A1 CA2343782A1 CA002343782A CA2343782A CA2343782A1 CA 2343782 A1 CA2343782 A1 CA 2343782A1 CA 002343782 A CA002343782 A CA 002343782A CA 2343782 A CA2343782 A CA 2343782A CA 2343782 A1 CA2343782 A1 CA 2343782A1
- Authority
- CA
- Canada
- Prior art keywords
- zone
- withdrawn
- sulfuric acid
- gas
- acid
- 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
- C01B17/90—Separation; Purification
-
- 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
- C01B17/48—Sulfur dioxide; Sulfurous acid
- C01B17/50—Preparation of sulfur dioxide
- C01B17/52—Preparation of sulfur dioxide by roasting sulfides
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Cleaning Or Drying Semiconductors (AREA)
- Treating Waste Gases (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Weting (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Catalysts (AREA)
Abstract
According to the present invention, nitrosyl sulphuric acid is mixed with SO2-containing sulphuric acid, and the acid mixture is removed and transferred towards a stripping area. An SO2-containing gas is fed simultaneously into the stripping area, and a gaseous mixture containing SO2 as well as nitrogen oxides is removed from the upper portion of said stripping area. The SO2-containing sulphuric acid is removed from the lower portion of the stripping area and is mixed at least partially with the nitrosyl sulphuric acid. The gaseous mixture removed from the stripping area is fed at a temperature of between 20 and 100~ C into a heating area where said gaseous mixture is heated to a temperature of about 700 to 1300~ C, thus resulting in the decomposition of nitrogen oxides, mainly of N2O.
Description
METHOD FOR REMOVING NITROGEN OXIDES FROM
NITROSYL SULPHURIC ACID
Description This invention relates to a process of removing nitrogen ox-ides from nitrosyl sulfuric acid by mixing nitrosyl sulfuric acid with S02-containing sulfuric acid in a mixing zone, where an acid mixture is withdrawn from the mixing zone and charged to a stripping zone, into which at the same time S02-containing gas is introduced, where the S02-containing gas at least partly flows upwards through the acid mixture, from the upper portion of the stripping zone a gas mixture containing S02 and nitrogen oxides is withdrawn, and from the lower por-tion of the stripping zone S02-containing sulfuric acid is withdrawn and at least partly introduced into the mixing zone.
Such process is known from WO-A-98/02 381. Nitrosyl sulfuric acid (HNOS04) is obtained in the large-scale production of sulfuric acid from S02-containing combustion ~r roasting gases, as these gases also contain nitrogen oxides. Details of the production of sulfuric acid ar.~ described for instance in Ullmann~s Encyclopedia of Industrial Chemistry, 5th edi-tion, vol. A25, pages 644 to 656.
In the process known from WO-A-98/02 381, the gas mixture withdrawn from the stripping zone contains disturbing gas constituents, in particular N20 and NO, which make it seem not advisable to introduce this gas mixture directly into a plant for producing sulfuric acid, as this would increase the formation of nitrosyl sulfuric acid.
It is the object underlying the invention to aftertreat the gas mixture withdrawn from the stripping zone in an easy way, in order to at least partly destroy N20 and/or NO. In accor-dance with the invention this is achieved in that the gas mixture is withdrawn from the stripping zone with a tempera-ture in the range from 20 to 100°C and is passed through a heating zone, in which the gas mixture is heated to tempera-tures in the range from 700 to 1300°C and preferably 800 to 1200°C. As a result, the N20 and NO molecules will wholly or partly be decomposed, without disturbing amounts of nitrogen oxides again being formed from nitrogen and oxygen.
Heating may for instance be effected in a burner, and it is particularly advantageous to utilize an existing roasting or combustion as heating zone. It is expedient to ensure a long enough dwell time of the gas mixture in the heating zone, which dwell time usually lies in the range from 1 to 10 sec.
Usually, the gas mixture withdrawn from the stripping zone contains 0.02 to 2 vol-a N20 and 0.01 to 1 vol-% NO, calcu-lated anhydrous. In the heating zone it is ensured that the content of N20 and NO, based on the amount of the gas mixture introduced, decreases to half or less or virtually disappears completely.
NITROSYL SULPHURIC ACID
Description This invention relates to a process of removing nitrogen ox-ides from nitrosyl sulfuric acid by mixing nitrosyl sulfuric acid with S02-containing sulfuric acid in a mixing zone, where an acid mixture is withdrawn from the mixing zone and charged to a stripping zone, into which at the same time S02-containing gas is introduced, where the S02-containing gas at least partly flows upwards through the acid mixture, from the upper portion of the stripping zone a gas mixture containing S02 and nitrogen oxides is withdrawn, and from the lower por-tion of the stripping zone S02-containing sulfuric acid is withdrawn and at least partly introduced into the mixing zone.
Such process is known from WO-A-98/02 381. Nitrosyl sulfuric acid (HNOS04) is obtained in the large-scale production of sulfuric acid from S02-containing combustion ~r roasting gases, as these gases also contain nitrogen oxides. Details of the production of sulfuric acid ar.~ described for instance in Ullmann~s Encyclopedia of Industrial Chemistry, 5th edi-tion, vol. A25, pages 644 to 656.
In the process known from WO-A-98/02 381, the gas mixture withdrawn from the stripping zone contains disturbing gas constituents, in particular N20 and NO, which make it seem not advisable to introduce this gas mixture directly into a plant for producing sulfuric acid, as this would increase the formation of nitrosyl sulfuric acid.
It is the object underlying the invention to aftertreat the gas mixture withdrawn from the stripping zone in an easy way, in order to at least partly destroy N20 and/or NO. In accor-dance with the invention this is achieved in that the gas mixture is withdrawn from the stripping zone with a tempera-ture in the range from 20 to 100°C and is passed through a heating zone, in which the gas mixture is heated to tempera-tures in the range from 700 to 1300°C and preferably 800 to 1200°C. As a result, the N20 and NO molecules will wholly or partly be decomposed, without disturbing amounts of nitrogen oxides again being formed from nitrogen and oxygen.
Heating may for instance be effected in a burner, and it is particularly advantageous to utilize an existing roasting or combustion as heating zone. It is expedient to ensure a long enough dwell time of the gas mixture in the heating zone, which dwell time usually lies in the range from 1 to 10 sec.
Usually, the gas mixture withdrawn from the stripping zone contains 0.02 to 2 vol-a N20 and 0.01 to 1 vol-% NO, calcu-lated anhydrous. In the heating zone it is ensured that the content of N20 and NO, based on the amount of the gas mixture introduced, decreases to half or less or virtually disappears completely.
Embodiments of the process will be explained with reference to the drawing. The drawing illustrates a flow diagram of the process.
In a plant 1 for producing sulfuric acid from So2-containing gas, which is supplied via line 2, product sulfuric acid is produced, which is withdrawn via line 3. At the same time, a condensate is produced, whose main constituent is nitrosyl sulfuric acid, which is withdrawn via line 4. In a mixing zone 5, the condensate is mixed with sulfuric acid from line 6, in which So2 is dissolved. Usually, the sulfuric acid from line 6 is saturated with S02, and the H2SO4 content of the aqueous solution lies in the range from 5 to 40 wt-%.
In formal terms, nitrosyl sulfuric acid can be reacted with So2 and water to form sulfuric acid and N2. In the mixing zone 5, however, the reaction S02 + 2HNOS04 + 2H20 > 3H2S04 + 2N0 takes place for instance. It is noted that the acid mixture, which is obtained in the mixing zone 5 and via line 8 is first of all supplied to an indirect cooler 9, contains NO
and also N20. with temperatures of 20 to 100°C and preferably not more than 70°C, the acid mixture is introduced through line 10 into a stripping column 11. The column has a portion 12 with gas- and liquid-permeable trays or packings, in order to intensify the contact between gas and liquid. As stripping gas, S02-containing gas is introduced into the lower portion of the column 11, which gas is supplied via line 13. The pressure in the column 11 usually lies in the range from 0.9 to 10 bar. In the bottom of the column 11, sulfuric acid is accumulated, whose concentration is adjusted by adding water from line 14. This sulfuric acid is withdrawn via line 15 by means of the pump 16 and at least partly supplied through line 6 to the mixing zone 5. An excess of sulfuric acid is withdrawn via line 6a.
From the upper portion of the column 11 a gas mixture is withdrawn via line 17, which contains S02, N20 and NO. This gas mixture is added to an Oz-containing gas, which is sup-plied to the roasting furnace 19 via line 18. In the furnace 19, sulfidic ore is roasted in a fluidized bed at tempera-tures of 750 to 1100°C, in order to produce S02-containing gas, which is discharged via line 20. In the roasting fur-nace 19, the gas dwells in line 17 for 1 to 10 sec and usu-ally for at least 2 sec, where N20 and NO are largely decom-posed to obtain nitrogen and oxygen, and NOX is not formed again. The gas from line 20 is passed through a cyclone 21 for dedusting and via line 22 flows to a gas cleaning 23, which in a manner known per se is designed as wet cleaning or as wet cleaning in combination with an electrical gas clean-ing. Finally, the S02-containing gas is supplied to the sul-furic acid production 1 via line 2.
Example:
In a procedure corresponding to the drawing, the following is done, where the data have been calculated in part:
From the plant 1, 79 1/h condensate are withdrawn via line 4, which condensate contains nitrosyl sulfuric acid correspond-ing to an N203 amount of 6.5 kg/h. 12300 kg/h sulfuric acid with 30 wt-o H2S04 and 1.4 g/1 S02 are added to the mixer through line 6. 550 kg/h of this acid are withdrawn via line 6a and delivered to the plant 1. The acid of line 10 has a temperature of 37°C, and it contains 1.23 g/1 S02. To the stripping column 11, 465 kg/h water are supplied through line 14, and through line 13, 450 Nm3/h of a gas mixture including 6.2 vol-% S02 are supplied, which gas mixture was branched off from the mixture of line 2. In the gas mixture of line 17 there are found for instance 3800 ppm N2o, 1800 ppm NO and 5.5 vol-% S02. Together with 38000 Nm3/h air, this mixture is feed into a pyrite roasting 19, where the gas dwell time is 5 sec. In the gas mixture of line 20, which is rich in S02 and has a temperature of 960°C, there can still be found 2 ppm N20 and 100 ppm NO.
If the nitrosyl sulfuric acid 4 would be removed in some other way, e.g. by adding hydrazine, where for instance line 17 would be omitted, line 20 still has an NO content of 90-95 ppm, which leads to the formation of nitrosyl sulfuric acid in the plant 1. In the procedure in accordance with the in-vention, the entire nitrosyl sulfuric acid produced is re-moved without adding foreign chemicals.
In a plant 1 for producing sulfuric acid from So2-containing gas, which is supplied via line 2, product sulfuric acid is produced, which is withdrawn via line 3. At the same time, a condensate is produced, whose main constituent is nitrosyl sulfuric acid, which is withdrawn via line 4. In a mixing zone 5, the condensate is mixed with sulfuric acid from line 6, in which So2 is dissolved. Usually, the sulfuric acid from line 6 is saturated with S02, and the H2SO4 content of the aqueous solution lies in the range from 5 to 40 wt-%.
In formal terms, nitrosyl sulfuric acid can be reacted with So2 and water to form sulfuric acid and N2. In the mixing zone 5, however, the reaction S02 + 2HNOS04 + 2H20 > 3H2S04 + 2N0 takes place for instance. It is noted that the acid mixture, which is obtained in the mixing zone 5 and via line 8 is first of all supplied to an indirect cooler 9, contains NO
and also N20. with temperatures of 20 to 100°C and preferably not more than 70°C, the acid mixture is introduced through line 10 into a stripping column 11. The column has a portion 12 with gas- and liquid-permeable trays or packings, in order to intensify the contact between gas and liquid. As stripping gas, S02-containing gas is introduced into the lower portion of the column 11, which gas is supplied via line 13. The pressure in the column 11 usually lies in the range from 0.9 to 10 bar. In the bottom of the column 11, sulfuric acid is accumulated, whose concentration is adjusted by adding water from line 14. This sulfuric acid is withdrawn via line 15 by means of the pump 16 and at least partly supplied through line 6 to the mixing zone 5. An excess of sulfuric acid is withdrawn via line 6a.
From the upper portion of the column 11 a gas mixture is withdrawn via line 17, which contains S02, N20 and NO. This gas mixture is added to an Oz-containing gas, which is sup-plied to the roasting furnace 19 via line 18. In the furnace 19, sulfidic ore is roasted in a fluidized bed at tempera-tures of 750 to 1100°C, in order to produce S02-containing gas, which is discharged via line 20. In the roasting fur-nace 19, the gas dwells in line 17 for 1 to 10 sec and usu-ally for at least 2 sec, where N20 and NO are largely decom-posed to obtain nitrogen and oxygen, and NOX is not formed again. The gas from line 20 is passed through a cyclone 21 for dedusting and via line 22 flows to a gas cleaning 23, which in a manner known per se is designed as wet cleaning or as wet cleaning in combination with an electrical gas clean-ing. Finally, the S02-containing gas is supplied to the sul-furic acid production 1 via line 2.
Example:
In a procedure corresponding to the drawing, the following is done, where the data have been calculated in part:
From the plant 1, 79 1/h condensate are withdrawn via line 4, which condensate contains nitrosyl sulfuric acid correspond-ing to an N203 amount of 6.5 kg/h. 12300 kg/h sulfuric acid with 30 wt-o H2S04 and 1.4 g/1 S02 are added to the mixer through line 6. 550 kg/h of this acid are withdrawn via line 6a and delivered to the plant 1. The acid of line 10 has a temperature of 37°C, and it contains 1.23 g/1 S02. To the stripping column 11, 465 kg/h water are supplied through line 14, and through line 13, 450 Nm3/h of a gas mixture including 6.2 vol-% S02 are supplied, which gas mixture was branched off from the mixture of line 2. In the gas mixture of line 17 there are found for instance 3800 ppm N2o, 1800 ppm NO and 5.5 vol-% S02. Together with 38000 Nm3/h air, this mixture is feed into a pyrite roasting 19, where the gas dwell time is 5 sec. In the gas mixture of line 20, which is rich in S02 and has a temperature of 960°C, there can still be found 2 ppm N20 and 100 ppm NO.
If the nitrosyl sulfuric acid 4 would be removed in some other way, e.g. by adding hydrazine, where for instance line 17 would be omitted, line 20 still has an NO content of 90-95 ppm, which leads to the formation of nitrosyl sulfuric acid in the plant 1. In the procedure in accordance with the in-vention, the entire nitrosyl sulfuric acid produced is re-moved without adding foreign chemicals.
Claims (4)
1. A process of removing nitrogen oxides from nitrosyl sul-furic acid by mixing the nitrosyl sulfuric acid with SO2-containing sulfuric acid in a mixing zone, where an acid mixture is withdrawn from the mixing zone and charged to a stripping zone, into which SO2-containing gas is intro-duced at the same time, where the SO2-containing gas at least partly flows upwards through the acid mixture, from the upper portion of the stripping zone a gas mixture containing SO2 and nitrogen oxides is withdrawn, and from the lower portion of the stripping zone SO2-containing sulfuric acid is withdrawn and at least partly introduced into the mixing zone, characterized in that the gas mix-ture is withdrawn from the stripping zone with a tempera-ture in the range from 20 to 100°C and passed through a heating zone, in which the gas mixture is heated to tem-peratures in the range from 700 to 1300°C.
2. The process as claimed in claim 1, characterized in that the gas mixture withdrawn from the stripping zone con-tains 0.02 to 2 vol-% N2O, calculated anhydrous, and at least 50 % of the N2O are destroyed in the heating zone.
3. The process as claimed in claim 1 or 2, characterized in that as heating zone there is used a roasting or com-bustion of sulfur or sulfur-containing solids for produc-ing an SO2-containing gas.
4. The process as claimed in claim 1 or any of the preceding claims, characterized in that the sulfuric acid withdrawn from the lower portion of the stripping zone is saturated with SO2.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19839674.0 | 1998-09-01 | ||
| DE19839674A DE19839674A1 (en) | 1998-09-01 | 1998-09-01 | Process for removing nitrogen oxides from nitrosylsulfuric acid |
| PCT/EP1999/005954 WO2000012429A1 (en) | 1998-09-01 | 1999-08-13 | Method for removing nitrogen oxides from nitrosyl sulphuric acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2343782A1 true CA2343782A1 (en) | 2000-03-09 |
Family
ID=7879345
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002343782A Abandoned CA2343782A1 (en) | 1998-09-01 | 1999-08-13 | Method for removing nitrogen oxides from nitrosyl sulphuric acid |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP1144304B1 (en) |
| AT (1) | ATE299472T1 (en) |
| AU (1) | AU764204B2 (en) |
| CA (1) | CA2343782A1 (en) |
| DE (2) | DE19839674A1 (en) |
| MX (1) | MXPA01003152A (en) |
| PE (1) | PE20001140A1 (en) |
| PL (1) | PL347163A1 (en) |
| WO (1) | WO2000012429A1 (en) |
| ZA (1) | ZA995588B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107311127A (en) * | 2017-06-22 | 2017-11-03 | 江苏依柯化工有限公司 | A kind of production method of salt-free nitrosyl sulfuric acid |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10050526A1 (en) * | 2000-10-11 | 2002-04-25 | Sachtleben Chemie Gmbh | Removal of nitrosylsulfuric acid from sulfuric acid process involves thermal cracking, preferably in existing roasting or combustion zone for sulfur dioxide production |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB348866A (en) * | 1930-05-06 | 1931-05-21 | Ig Farbenindustrie Ag | An improvement relating to the purification of sulphuric acid |
| GB667901A (en) * | 1939-06-26 | 1952-03-12 | Giuseppina Maragliano Busseti | Improved process for the intensive manufacture of sulphuric acid |
| GB671403A (en) * | 1949-06-20 | 1952-05-07 | Pietro Guareschi | Improvements in or relating to intensive processes for the manufacture of sulphuric acid |
| US4155989A (en) * | 1977-11-14 | 1979-05-22 | Ciba-Geigy Corporation | Removal of nitric acid from nitric acid-sulfuric acid mixtures |
| SU1586996A1 (en) * | 1988-02-29 | 1990-08-23 | Горьковский Политехнический Институт | Method of denitration of spent sulfuric acid |
| DE4002465A1 (en) * | 1990-01-28 | 1991-08-01 | Bayer Ag | Continuous prodn. of oleum and sulphuric acid by contact process - using added sulphur di:oxide with low nitrogen oxide content to minimise nitrous gas formation |
| ZA963521B (en) * | 1995-05-04 | 1997-11-03 | Metallgesellschaft Ag | Process of removing NOx from nitrosyl hydrogensulfate. |
-
1998
- 1998-09-01 DE DE19839674A patent/DE19839674A1/en not_active Withdrawn
-
1999
- 1999-08-13 PL PL99347163A patent/PL347163A1/en not_active IP Right Cessation
- 1999-08-13 CA CA002343782A patent/CA2343782A1/en not_active Abandoned
- 1999-08-13 MX MXPA01003152A patent/MXPA01003152A/en unknown
- 1999-08-13 AT AT99944391T patent/ATE299472T1/en not_active IP Right Cessation
- 1999-08-13 DE DE59912277T patent/DE59912277D1/en not_active Expired - Lifetime
- 1999-08-13 EP EP99944391A patent/EP1144304B1/en not_active Expired - Lifetime
- 1999-08-13 WO PCT/EP1999/005954 patent/WO2000012429A1/en active IP Right Grant
- 1999-08-13 AU AU57343/99A patent/AU764204B2/en not_active Ceased
- 1999-08-31 ZA ZA9905588A patent/ZA995588B/en unknown
- 1999-08-31 PE PE1999000872A patent/PE20001140A1/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107311127A (en) * | 2017-06-22 | 2017-11-03 | 江苏依柯化工有限公司 | A kind of production method of salt-free nitrosyl sulfuric acid |
Also Published As
| Publication number | Publication date |
|---|---|
| PL347163A1 (en) | 2002-03-25 |
| WO2000012429A1 (en) | 2000-03-09 |
| EP1144304B1 (en) | 2005-07-13 |
| DE59912277D1 (en) | 2005-08-18 |
| ATE299472T1 (en) | 2005-07-15 |
| MXPA01003152A (en) | 2003-05-15 |
| ZA995588B (en) | 2001-02-28 |
| EP1144304A1 (en) | 2001-10-17 |
| PE20001140A1 (en) | 2000-11-18 |
| AU764204B2 (en) | 2003-08-14 |
| DE19839674A1 (en) | 2000-03-02 |
| AU5734399A (en) | 2000-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| GB1601315A (en) | Purification of industrial waste gases | |
| EP0218411B1 (en) | Sulphuric acid | |
| US4634582A (en) | Sulfur dioxide removal process | |
| CS154892A3 (en) | Process for waste sulfuric acid regeneration | |
| AU764204B2 (en) | Method for removing nitrogen oxides from nitrosyl sulphuric acid | |
| US3761575A (en) | Process for the cracking of ammonium sulfate | |
| EP0439742B1 (en) | Process for the preparation of oleum and sulfuric acid | |
| US4131437A (en) | Process for the continuous multistage degasification of liquid sulfur | |
| CA1196473A (en) | Apparatus and processes for the concentration of sulphuric acid | |
| US3755549A (en) | Catalytic oxidation of so2 to so3 | |
| US5082645A (en) | Waste acid recovery process | |
| CA2453811C (en) | Process for condensation of sulphuric acid vapours to produce sulphuric acid | |
| US3954955A (en) | Process for working up the wash solution obtained in the washing of SO2 -containing off-gases | |
| US3649188A (en) | Method of converting sulfur dioxide to sulfuric acid | |
| CA1158023A (en) | Process for removing phosphorus in vapor form and phosphanes from gas mixtures | |
| AU714625B2 (en) | Process of removing NOx from nitrosyl hydrogensulfate | |
| US2389071A (en) | Production of sulphur dioxide | |
| US6238639B1 (en) | Process for removing NOx from nitrosylsulphuric acid | |
| CA2269630C (en) | Process for preparing sulphuric acid from gasses containing so3 and gaseous nitrosylsulphuric acid | |
| US1102715A (en) | Purification of mixtures containing nitrids. | |
| US3943237A (en) | Production of sulfuric acid from the scrubbing solution obtained in the desulfurization of coke-oven gas | |
| US1291909A (en) | Method of manufacturing concentrated nitrous gases. | |
| CA2540870A1 (en) | Desulphurization of odorous gases of a pulp mill | |
| US3950502A (en) | Process for working up the scrubbing solution obtained in the scrubbing of So2 -containing waste gases | |
| KR100428255B1 (en) | PROCESS FOR REMOVING NOx FROM NITROSYL HYDROGENSULFATE |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |