GB2056420A - Removal of nitrogen oxides - Google Patents
Removal of nitrogen oxides Download PDFInfo
- Publication number
- GB2056420A GB2056420A GB7913047A GB7913047A GB2056420A GB 2056420 A GB2056420 A GB 2056420A GB 7913047 A GB7913047 A GB 7913047A GB 7913047 A GB7913047 A GB 7913047A GB 2056420 A GB2056420 A GB 2056420A
- Authority
- GB
- United Kingdom
- Prior art keywords
- nitrogen
- nitric acid
- oxides
- oxygen
- solution
- 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.)
- Withdrawn
Links
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 title 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 90
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 47
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 45
- 239000001301 oxygen Substances 0.000 claims abstract description 37
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 37
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000007789 gas Substances 0.000 claims abstract description 33
- 238000000034 method Methods 0.000 claims abstract description 20
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229940006477 nitrate ion Drugs 0.000 claims abstract description 13
- 239000002440 industrial waste Substances 0.000 claims abstract description 7
- -1 nitrite ions Chemical class 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims description 22
- 239000006096 absorbing agent Substances 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 10
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 claims description 4
- 229940005654 nitrite ion Drugs 0.000 claims description 4
- 238000012856 packing Methods 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 2
- IOVCWXUNBOPUCH-UHFFFAOYSA-N Nitrous acid Chemical compound ON=O IOVCWXUNBOPUCH-UHFFFAOYSA-N 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims description 2
- 230000008030 elimination Effects 0.000 claims description 2
- 238000003379 elimination reaction Methods 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 239000007791 liquid phase Substances 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 claims description 2
- 238000007254 oxidation reaction Methods 0.000 claims description 2
- 150000002926 oxygen Chemical class 0.000 claims description 2
- 239000012071 phase Substances 0.000 claims description 2
- 238000010926 purge Methods 0.000 claims description 2
- 239000002912 waste gas Substances 0.000 claims description 2
- 238000010924 continuous production Methods 0.000 claims 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
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
A method of removing at least one oxide of nitrogen from an industrial waste gas stream comprises contacting the stream with an aqueous nitrate-ion containing solution and reacting the nitrite ions thus produced with oxygen to form nitric acid.
Description
SPECIFICATION
Reduction of oxides of nitrogen in off-gases.
The present invention relates to a method of removing oxides of nitrogen from a gas stream.
A number of patents have been granted to Mr.
D. W. Bolme, e.g. United States Patent Nos.
4Q53555,4118467 and 4138470 relating to the elimination by oxidation of oxides of nitrogen from waste gases. Copending British Patent Application No. 40338/77 describes and claims the use of nitrate-ion containing solutions as the oxidising medium.
As described in the above patents, gases containing oxides of nitrogen are washed by nitric acid. This causes the oxides of nitrogen to dissolve and react with the nitric acid, thereby reducing the level of oxides of nitrogen in the gases. In Bolme's patents the oxides of nitrogen are recovered from the washing nitric acid by means such as steam stripping, vacuum stripping, etc.
The invention to which the current patent application relates concerns the means whereby the oxides of nitrogen are removed from the washing nitric acid. Instead of stripping the oxides of nitrogen, the solution of nitric acid containing the oxides of nitrogen enters a tower into which an oxygen-containing gas has been passed. As the NOx is desorbed from the solution it reacts with the oxygen and in its higher oxidised state reacts with the liquid to form more nitric acid. In essence, the invention speeds up the reaction normally taking place in the top of a nitric acid absorber because of much higher partial pressure of oxygen.
In accordance with the present invention there is provided a method of removing at least one oxide of nitrogen from an industrial waste gas stream which comprises contacting the stream with an aqueous nitrate-ion containing solution and reacting the nitrite ions thus produced with oxygen to form nitric acid.
Preferably the nitrate-ion containing solution comprises aqueous nitric acid, and the nitric acid produced in the nitrite-ion reaction step is returned for use in the contacting step.
The solution of nitric acid containing the dissolved oxides of nitrogen and nitrous acid is pumped to a column containing both a gas-liquid contacting device, such as packing, as well as liquid hold-up devices to facilitate liquid phase reactions, and in which gaseous oxygen has a partial pressure of 0.2 to 30 atmospheres, preferably 1 to 10 atmospheres.
It will probably be necessary to have a pump to pump the nitric acid solution used to absorb the oxides of nitrogen around the system and it may be desirable to heat or cool the liquid prior to it entering either or both the device in which it absorbs oxides of nitrogen and the device in which those oxides of nitrogen are desorbed. It may also be desirable to purge some of the gases in the
oxides of nitrogen desorber to maintain a higher
partial pressure of oxygen. In order not to lose
oxygen dissolved in the liquid leaving the desorber, it may be desirable to strip out some of the dissolved oxygen and/or to inject into the
liquid a small quantity of the nitric acid solution
containing dissolved oxides of nitrogen to react with the oxygen contained in the solution.
There now follows a detailed description of one embodiment of the invention.
In a nitric acid plant the top of the main
absorber is modified so that gases passing up it
are made to contact a solution of nitric acid which
is separated from the main flow of liquid down the
main abosrber which becomes the product acid.
This flow of absorbing nitric acid picks up oxides
of nitrogen from the gases flowing up the main
absorber. The solution of nitric acid containing the oxides of nitrogen leave the main absorber and are pumped to another tower (the desorber) hereinafter referred to as the oxygen tower, which contains alternate sections of packing and liquid
hold-up trays. The gas-laden liquid flows down this tower and in doing so gives up oxides of nitrogen into the gas phase where they are oxidised. In the higher oxidised state the gases react with the solution to form more nitric acid.
into this oxygen tower is passed oxygen or an oxygen-containing gas, possibly from a liquid oxygen storage vessel. The partial pressure of oxygen is maintained over and above the pressure in the oxygen tower caused by nitrogen and other
gases desorbing from the gas-laden nitric acid
solution entering the oxygen tower. The liquid leaving the tower may possibly pass through a liquid turbine. It is then passed back to the main absorber to start the cycle again.
The preferred features of the remainder of the NO, absorption process are described in copending Application No. 40338/77.
1. A method of removing at least one oxide of nitrogen from an industrial waste gas stream which comprises contacting the stream with an aqueous nitrate-ion containing solution and reacting the nitrite ions thus produced with oxygen to form nitric acid.
2. A method as claimed in Claim 1 wherein the nitrate-ion containing solution comprises aqueous nitric acid, and wherein the nitric acid produced in the nitrite-ion reaction step is returned for use in the contacting step.
3. A method as claimed in claim 1 or claim 2 wherein the nitrate-ion reaction step is effected at a pressure sufficient to leave any gaseous impurities in the oxygen in solution.
4. A method as claimed in any one of the preceding claims wherein the industrial waste gas stream is the tail gas stream of a nitric acid plant.
5. A method as claimed in any one of the preceding claims wherein the method is operated
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
1. A method of removing at least one oxide of nitrogen from an industrial waste gas stream which comprises contacting the stream with an aqueous nitrate-ion containing solution and reacting the nitrite ions thus produced with oxygen to form nitric acid.
2. A method as claimed in Claim 1 wherein the nitrate-ion containing solution comprises aqueous nitric acid, and wherein the nitric acid produced in the nitrite-ion reaction step is returned for use in the contacting step.
3. A method as claimed in claim 1 or claim 2 wherein the nitrate-ion reaction step is effected at a pressure sufficient to leave any gaseous impurities in the oxygen in solution.
4. A method as claimed in any one of the preceding claims wherein the industrial waste gas stream is the tail gas stream of a nitric acid plant.
5. A method as claimed in any one of the preceding claims wherein the method is operated as a continuous process.
6. A method as claimed in claim 1 substantially as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7913047A GB2056420A (en) | 1979-04-12 | 1979-04-12 | Removal of nitrogen oxides |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7913047A GB2056420A (en) | 1979-04-12 | 1979-04-12 | Removal of nitrogen oxides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2056420A true GB2056420A (en) | 1981-03-18 |
Family
ID=10504553
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7913047A Withdrawn GB2056420A (en) | 1979-04-12 | 1979-04-12 | Removal of nitrogen oxides |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2056420A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT380799B (en) * | 1983-04-20 | 1986-07-10 | Tungsram Reszvenytarsasag | METHOD AND DEVICE FOR ABSORPTION OF A GAS RESISTING FROM A CHEMICAL REACTION, MADE OF NITROGEN OXIDS OF THE GENERAL FORMULA NO X AND WATER VAPOR |
| AT383506B (en) * | 1985-08-22 | 1987-07-10 | Schmid Peter J | METHOD FOR REMOVING AND RECYCLING NITROGEN OXIDS IN SMOKE GASES |
| CN100396360C (en) * | 2006-04-24 | 2008-06-25 | 南京大学 | A nitric oxides (NOX) waste pollution control in industrial process and resource reclaiming method |
| CN103566739A (en) * | 2013-10-24 | 2014-02-12 | 南京大学 | Method for resource recovery of nitrogen oxides (NOx) in nitric acid industrial waste gas |
| DE102015014185A1 (en) * | 2015-11-03 | 2017-05-18 | Messer Group Gmbh | Process for the preparation of peroxo nitric acid |
-
1979
- 1979-04-12 GB GB7913047A patent/GB2056420A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT380799B (en) * | 1983-04-20 | 1986-07-10 | Tungsram Reszvenytarsasag | METHOD AND DEVICE FOR ABSORPTION OF A GAS RESISTING FROM A CHEMICAL REACTION, MADE OF NITROGEN OXIDS OF THE GENERAL FORMULA NO X AND WATER VAPOR |
| AT383506B (en) * | 1985-08-22 | 1987-07-10 | Schmid Peter J | METHOD FOR REMOVING AND RECYCLING NITROGEN OXIDS IN SMOKE GASES |
| CN100396360C (en) * | 2006-04-24 | 2008-06-25 | 南京大学 | A nitric oxides (NOX) waste pollution control in industrial process and resource reclaiming method |
| CN103566739A (en) * | 2013-10-24 | 2014-02-12 | 南京大学 | Method for resource recovery of nitrogen oxides (NOx) in nitric acid industrial waste gas |
| DE102015014185A1 (en) * | 2015-11-03 | 2017-05-18 | Messer Group Gmbh | Process for the preparation of peroxo nitric acid |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |