GB1558659A - Methods of stripping ammonia from ammoniacal solutions - Google Patents
Methods of stripping ammonia from ammoniacal solutions Download PDFInfo
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- GB1558659A GB1558659A GB5013/78A GB501378A GB1558659A GB 1558659 A GB1558659 A GB 1558659A GB 5013/78 A GB5013/78 A GB 5013/78A GB 501378 A GB501378 A GB 501378A GB 1558659 A GB1558659 A GB 1558659A
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims description 96
- 229910021529 ammonia Inorganic materials 0.000 title claims description 48
- 238000000034 method Methods 0.000 title claims description 42
- 239000007788 liquid Substances 0.000 claims description 52
- 238000006243 chemical reaction Methods 0.000 claims description 36
- 239000007789 gas Substances 0.000 claims description 32
- 238000002485 combustion reaction Methods 0.000 claims description 24
- 238000001704 evaporation Methods 0.000 claims description 24
- 238000007654 immersion Methods 0.000 claims description 22
- 239000010802 sludge Substances 0.000 claims description 21
- 239000012530 fluid Substances 0.000 claims description 18
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 16
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 16
- 229940043430 calcium compound Drugs 0.000 claims description 16
- 150000001674 calcium compounds Chemical class 0.000 claims description 16
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 16
- 239000004571 lime Substances 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000000428 dust Substances 0.000 claims description 13
- 239000002918 waste heat Substances 0.000 claims description 13
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 12
- 239000000920 calcium hydroxide Substances 0.000 claims description 10
- 235000011116 calcium hydroxide Nutrition 0.000 claims description 10
- 239000002737 fuel gas Substances 0.000 claims description 10
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 9
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 9
- 239000005864 Sulphur Substances 0.000 claims description 9
- 239000011575 calcium Substances 0.000 claims description 9
- 229910052791 calcium Inorganic materials 0.000 claims description 9
- 235000011132 calcium sulphate Nutrition 0.000 claims description 9
- 239000000567 combustion gas Substances 0.000 claims description 9
- 239000003546 flue gas Substances 0.000 claims description 9
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 8
- 239000001175 calcium sulphate Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 7
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 6
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 6
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 6
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 5
- 239000000292 calcium oxide Substances 0.000 claims description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 4
- 239000012295 chemical reaction liquid Substances 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 4
- 239000001117 sulphuric acid Substances 0.000 claims description 4
- 235000011149 sulphuric acid Nutrition 0.000 claims description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 3
- 238000010791 quenching Methods 0.000 claims description 3
- 230000000171 quenching effect Effects 0.000 claims description 3
- AGVJBLHVMNHENQ-UHFFFAOYSA-N Calcium sulfide Chemical compound [S-2].[Ca+2] AGVJBLHVMNHENQ-UHFFFAOYSA-N 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- 238000009833 condensation Methods 0.000 claims description 2
- 230000005494 condensation Effects 0.000 claims description 2
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 2
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 229960005069 calcium Drugs 0.000 description 8
- 229960003563 calcium carbonate Drugs 0.000 description 5
- 235000010216 calcium carbonate Nutrition 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 239000011541 reaction mixture Substances 0.000 description 4
- 239000002351 wastewater Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 3
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 3
- 239000001166 ammonium sulphate Substances 0.000 description 3
- 235000011130 ammonium sulphate Nutrition 0.000 description 3
- -1 ammonium sulphate Chemical compound 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 235000011121 sodium hydroxide Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/10—Separation of ammonia from ammonia liquors, e.g. gas liquors
-
- 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)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Physical Water Treatments (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
- Treating Waste Gases (AREA)
Description
(54) IMPROVEMENTS RELATING TO METHODS OF STAÌPPING AMMONIA FROM AMMONIACAL SOLUTIONS
(71) We, DR. C. OTS & COMP.
GmbH, a German Body Corporate, of Chnststrasse 9, Bochum 4630, Germany, and SIDMAR N.V., a Belgian Company, of
Presedent Kennedylaan J.F., 51, Ghent 9020, Belgium, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The invention relates to a method of stripping ammonia from ammoniacal solutions.
Cokeoven liquor, for example, contains various substances, including free and bonded ammonia. For years, the prior-art method of completely recovering the ammonia has been to treat the liquor in two stages. Usually the method is as fclllows:- In a first stripping stage the preheated coke-oven liquor is treated with vapour or evaporating liquid from the second column.
The liquor enters the top of a column and travels through a number of exchange trays, whereas the vapour ar evaporating liquid is introduced into the second column from beneath. In this manner, the free ammonta and any non-bonded components are expelled. In order to strip the bonded ammonia, milk of lime or caustic soda solution is usually added to the effluent from the first stripping column. The ammonia is liberated, by substituting calcium for ammonia, and can be expelled with water-vapour as in the first column.
The effluent from the bottom of the lime column contains the lime sludge, calcium sulphate, unburnt hydroxide, calcium car bonate and other calcium compounds. The sludge is separated in downstream settling containers and, after drying, is stored in dumps without being re uso i.
Wastewater containing bonded but not free ammonia can be processed in a single stage, in which case lime is added at the top of the column. The resulting lime sludge is processed as previously described.
As a result of recent environmental regulations, the dumping of lime sludge has become progressively more difficult and expensive. It is no answer to replace calcium by sodium, since this greatly increases the salt burden of the waste water.
An object of the invention is to avoid dumping lime sludge or additional burdening of the waste water.
According to the invention, therefore, there is provided a method of stripping ammonia from ammoniacal solutions, which are treated with milk of lime in a stripping column and from which the ammonia is expelled with hot gas, vapour or evaporating liquid whereas the effluent from the bottom, containing lime sludge, calcium sfllrhate, sunburnt hydroxide, calcium carbonate and other calcium compounds, is withdrawn from the column and conveyed to a separator in which the sludge is separated from the liquid, and a pumpable sludge is withdrawn from the separator and burnt under reducing conditions in a combustion chamber in a supply of fuel gas and air at a temperature of 600 to 12000C, to create combustion products which are subsequently used for other purposes.
The resulting combustion gases may then be introduced into an immersion chamber in which the calcium compounds produced by combustion are converted to calcium hydroxide by an aqueous fluid, whereas the evaporating liquids produced are conveyed away for further treatment.
The reducing combustion is preferably brought abort at a temperature of 8X to 10000C and the resulting calcium com pounds consist mainly of calcium oxide.
Alternatively, reducing combustion may be brought about at a temperature of 600 to 900"C, so that the resulting calcium compounds consist mainly of calcium sulphide, in which case, advantageously the H to
H2O ratio or the CO to CO2 ratio is greater than 2 to 1. Aqueous fluid, which is part of the clear liquid separated in the separator, may be supplied to the immersion chamber.
In a preferred embodiment of the invention, the evaporating liquids withdrawn from the immersion chamber and obtained during quenching of the combustion gases are used for pre-heating the aqueous ammoniacal starting solution in an indirect heat exchanger. According to another feature, the gas condensate formed during cooling is recycled to the immersion chamber.
According to a preferred feature of the invention, in order to treat coke-oven liquor or the like, containing both bonded and free ammonia, the free ammonia is first stripped from the aqueous fluid in known manner in the top part of the column and the solution freed from free ammonia is introduced into the immersion chamber and, after reacting with the calcium oxide produced by combustion, the solution from the immersion chamber is supplied to the top of the bottom part of the stripping column, whereas the evaporating liquids from the immersion chamber are supplied to the column as stripping water-vapour.
When fuel gas and air burn under reducing conditions in a burner connected to the combustion chamber, the production of carbon dioxide cannot be avoided, even at an air coefficient of 0.6 to 0.9. The low temperature in the combustion chamber, into which lime sludge containing considerable quantities of water is sprayed, may further increase the formation of CO However, it is found that, in the case of the short-period combustion-chamber used, the waterlgas equilibrium, which is critical for CO2 formation, is kept constant at well above 1000"C. The reaction gas in the immersion chamber contains only 2 to 4 vol.% CO2, depending on the air coefficient and the fuel.
It has been found about 7 to 12% of the resulting carbon dioxide reacts with the calcium hydroxide-containing solution to form calcium carbonate. The calcium carbonate travels through the entire circuit, is separated in the separator, and is again supplied to the combustion chamber, during which process the entire circuit remains at equilibrium. The resulting blank value of the circulation can be up to 20% of the amount required in circulation in any case.
The amount of fuel gas must be increased in proportion to the circulation blank value, and the resulting amount of liberated energy cannot be efficiently used in all applications.
Accordingly, to obviate this disadvantage and improve the efficiency of the method, the hot combustion gases produced during combustion under reducing conditions may be cooled in a waste-heat boiler to a temperature above the dew point, and the dust consisting of calcium compounds is separated in a separator, conveyed to a reaction container and brought in contact with an aqueous liquid to form a new reaction liquid.
In one embodiment, the aqueous liquid is the liquid for treatment and the new liquid formed in the reaction container is supplied to the top of the stripping column.
In that case, the hot reaction gases leaving the separator may be used in an indirect heat exchanger for pre-heating the aqueous starting liquid.
Another preferred embodiment of the invention is used for stripping ammonia from coke-oven liquor or the like, containing both bonded and free ammonia, wherein the free ammonia is first stripped from the aqueous liquid in the top part of the column, and the solution freed from free ammonia is introduced into the reaction container and the new reaction liquid formed in the reaction chamber is applied to the top of the bottom part of the stripping column, whereas the reaction gases leaving the separator are introduced below into the bottom portion of the top part of the column, which bottom portion is not operated with lime. In that case, the aqueous liquid is a partly-treated liquid, and the hot reaction gases from the dust separator may be used in an indirect heat exchanger for pre-heating the waste-heat boiler feed water.
Advantageously the evaporating flquids produced in the reaction container are directly introduced into the evaporating liquid line extending from the stripping column, and the gas condensate produced during cooling in the waste heat boiler is recycled to the reaction container.
According to another preferred feature, the effective mean gas velocity in the waste-heat boiler is 20 to 60 mlsec, preferably 30 to 50 mlsec.
The invention may be performed in various ways and preferred embodiments thereof will now be described with reference to the accompanying drawings, in which: Figure 1 is a block diagram of one method of treating coke-oven liquor, according to the invention,
Figure 2 shows a method of this invention for treating liquor containing only bonded ammonia, e.g. ammonium sulphate,
Figure 3 shows another embodiment of the method of this invention of treating coke-oven liquor, and
Figure 4 shows a further embodiment of the method of this invention, used for treating liquor containing only bonded ammonia, e.g. ammonium sulphate.
As shown in Figures 1 and 3, coke-oven liquor for treatment is conveyed through a line 1 to the head of the top part 2 of a stripping column. Evaporating liquid 4 rising from the bottom part 3 of the column and also containing ammonia stripped in the bottom column is brought into intimate contact with the coke-oven liquor, via exchange trays. At the top of the column, the resulting ammonia is withdrawn through line 5, together with the evaporating liquid. Pretreated water travels along pipe 6 to an immersion chamber 7.
Waste water from the stripping column, after being freed from ammonia and other components, is conveyed along line 12 to a separator 13. Clear liquid, which runs off at the top, is withdrawn through a pipe 14 and sent for further treatment if required, whereas a pump 16 conveys lime sludge from the separator 13 in pumpable concentration along line 15 and via line 17 to a combustion-chamber 18. Fuel gas as required is supplied to the combustion chamber through line 19 and combustion air is supplied through line 20. A burner 21 produces a high flue gas into which the sludge is sprayed in finely-divided form. The reaction occurs at between 600 and 1200"C, preferably 800 and 1000"C.
In the reaction, the calcium components are converted to calcium oxide and the sulphur components to hydrogen sulphide. In the same method, organic constituents absorbed in the lime, e.g. tar, phenol and the like, are gasified or burnt.
In the embodiment in Figure 1, the resulting hot combustion gases from chamber 18 are brought, in chamber 7, into contact with the effluent from the top part 2 of the stripping column. The immersion chamber 7 is also a reaction container in which ammonia is substituted by calcium. The liquid reaction mixture is conveyed from chamber 7 through a pipe 8, a pump 9 and a line 10 at the top of the bottom part 3 of the stripping column. The evaporating liquids in chamber 7 are withdrawn through a line 11 and introduced through the bottom into the lower part 3 of the column, which is likewise equipped with exchange trays or corresponding other elements.As a result of the intimate contact between the two media, i.e. the evaporating liquid and the reaction mixture, the remaining liberated ammonia is driven from the reaction mixture and reaches the top part 2 of the stripper column, through an aperture between the top part and the bottom part of the column.
In the embodiment shown in Figure 3, the resulting hot combustion gases from chamber 18 are conveyed through a line 34 to a waste-heat boiler 35 and cooled to a temperature above the dew point. The resulting saturated vapour travels through a line 29 to the bottom part 3 of the stripping column. The cooled gas flows through line 36 into a dust separator 37.
After being separated, the dust travels through a cut-off device (not shown) and a line 42 to the reaction container 7, where the dust comes in contact with the pretreated liquor, so that the ammonia is replaced by calcium. The liquid reaction mixture is conveyed from container 7 through a line 8, a pump 9 and a line 10 to the top of the bottom part 3 of the column, whereas the evaporating liquid formed in the reaction container and consisting of ammonia and water-vapour is conveyed through a line 11 to the evaporating-liquid line 5.
The cooled gas leaving the dust separator 37 is conveyed through lines 38 and 39, either as a stripping gas to the top part 2 of the stripping column, or through a line 40 into a heat exchanger 22, where it is provisionally cooled, and through a line 41 to be used for another purpose. The heatexchanger 22 can be used either for preheating the liquid under treatment or for pre-heating the boiler feed water. Any gas condensate is withdrawn through a line 33 into container 7.
Figure 2 shows how the process is used for treating liquor containing only bonded ammonia, e.g. ammonium sulphate, in which case the content of hydrogen sulphide will be higher than during combustion under reducing conditions.
The liquor for treatment is conveyed through line 1 into a heat exchanger 22, where it is indirectly pre-heated by the hot evaporating liquids withdrawn from the immersion chamber 18, and travels through lines 23, 25 to the stripping column 2. The reaction fluid coming from chamber 7 is conveyed through line 8, pump 9 and line 24 to the liquor for treatment and travels therewith to the top of column 2, where most of the ammonia is substituted by calcium.
Column 2 is in one stage. The lower part of the column is supplied through line 29 with a sufficient quantity of stripping watervapour, which can be replaced by an inert gas. The ammoniacal evaporating liquids are withdrawn at the top of the column through line 5, whereas the water freed from ammonia and containing the corresponding calcium compound is conveyed through line 12 to the separating container 13. The clear fluid is withdrawn through line 14 from the top of container 13. A partial stream of fluid is conveyed through line 30, pump 31 and line 32 back to the immersion chamber 7.
The sludge (e.g. calcium sulphate) with drawn from column 2 through line 12 after settling in container 13, is conveyed, in pumpable concentration, via line 15, pump 16 and line 17, to the combustion chamber 18. As in the preceding example, heat is supplied by burning fuel gas with air, which are supplied to the burner 21 via lines 19 and 20.
When sulphate compounds are processed, the reaction temperature in combustion- chamber 18 is 800 to 1200 C, preferably 900 to 1000 C. The reaction gases are introduced into the fluid in chamber 7 and quenched therein. The resulting evaporating liquids and flue gas, which contains hydrogen sulphide when calcium sulphate is calcined, travel through line 11 to heat exchanger 22, in which most of the heat of condensation of the water is supplied to the water for treatment, which is flowing through line 1. The resulting gas condemn sate Is returned through line 33 to chamber 7.
The cooled flue gases can be given further treatment; in that they can be sent through a line 26 to a device 27, where, for example, they may be washed under oxidizing conditions and the hydrogen sulphide is obtained in the form of elemen- tary sulphur or alternatively elementary sulphur can be obtained in known manner in a Claus process, Device 27 may also be an apparatus for obtaining sulphuric acid.
The harmless gases withdrawn from device 27 are sent through line 28 fOr further use.
In the embodiment in Figure 4, the water or liquor for treatment travels through line 1 to a heat-exchanger 22, where it is indirectly heated by the hot flue gases from the dust-separator 37, and then travels through line 23 to the reaction container 7, where the pré-heated fluid is mixed with calcium hydroxide dust supplied through line 42 and caused to react. In this case, ammonia is replaced by calcium; liberated ammonia is conveyed through line 11 into the evaporátingwliquid line 5. The reaction fluid from container 7 is supplied through line 8, pump 9 and line 24 to the top of the column.
Column 2 is in a single stage. The stripping wàtervapour, which is g-enerated in a waste-heat boiler 33, is supplied to the bottom part of the column through a line 29. The ammoniacal evaporating liquids are withdrawn at the top of the column through line 5, whereas the water freed from ammonia and containing the corresponding calcium compounds is coni veyed through lifle 12 to the settrating container 13. The clear fluid is withdrawn through line 14 from the top part of container 13, whereas the sludge, e.g. calcium sulphates deposited in container 13 is conveyed in putnpable concentration through line 15, pump 16 and line 17 to the com bustion-chamber 18.As in the preceding example, heat is supplied by burning fuel gas with air, supplied to burner 21 through lines 19 and 20.
During the processing of sulphate com pounds, the reaction temperature in chamber 18 is 600 to 1200 C, preferably 800 to 100()0C. As before, the reaction gases are sent through line 34 to the waste-heat boiler 33 and cooled to a temperature above the dew-poilit. The gas is sent through line 36 to. the dust-separator 37 and through line 38 to the heat-exchanger 22. The lime dust In the separator is conveyed through a cut-off device (not shown) and line 42 to container 7.
The cooled flue gases can receive further treatment. Thus they may be sent through line 26 to X device 27 for further processing, e.g washing under oxidising conditions in which the hydrogen sulphide is obtained as elementary sulphur, or treated in a Claus process in which elementary sulphur is obtained in known manner. Device 27 can also be an apparatus for obtaining sulphuric acid. The hflrmless gases withdrawn from device 27 are sent through line 28 for further use.
WIlAT WE CLAIM IS:
1. A method of stripping ammonia from ammoniacal solutions, which are treated with milk of lime in a stripping column and from which the ammonia is expelled with hot gas, vapour or evaporatmg liquid whereas the effluent from the bottom, con taining lime sludge, calcium sulphate, unburnt hydroxide, calcium carbonate and other calcium compounds, is withdrawn from the column and conveyed to a separator in which the sludge is separated from the liquid, and a pumpable sludge is withdrawn from the separator and burnt under reducing conditions in a combustion chamber in a supply of fuel gas and air at a temperature of 600 to 1200 C, to create combustion products which are subsequently used for other purposes.
2. A method according to claim l; wherein the resulting combustion gases are introduced Into an - immersion chamber in which the calcium compounds produced by combustion are converted to calcium hydroxide by an aqueous fluid, whereas the evaporating liquids produced are Conveyed away for further treatment 3. A method according to claim 2, wherein part of the liquid separated in the separator is supplied to the immersion chamber.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (20)
1. A method of stripping ammonia from ammoniacal solutions, which are treated with milk of lime in a stripping column and from which the ammonia is expelled with hot gas, vapour or evaporatmg liquid whereas the effluent from the bottom, con taining lime sludge, calcium sulphate, unburnt hydroxide, calcium carbonate and other calcium compounds, is withdrawn from the column and conveyed to a separator in which the sludge is separated from the liquid, and a pumpable sludge is withdrawn from the separator and burnt under reducing conditions in a combustion chamber in a supply of fuel gas and air at a temperature of 600 to 1200 C, to create combustion products which are subsequently used for other purposes.
2. A method according to claim l; wherein the resulting combustion gases are introduced Into an - immersion chamber in which the calcium compounds produced by combustion are converted to calcium hydroxide by an aqueous fluid, whereas the evaporating liquids produced are Conveyed away for further treatment
3. A method according to claim 2, wherein part of the liquid separated in the separator is supplied to the immersion chamber.
4. A method according to claim 2 or
claim 3, wherein the evaporating liquids withdrawn from the immersion chamber and obtained during quenching of the combustion gases are used for pre-heating the aqueous ammoniacal starting solution in an indirect heat exchanger.
5. A method according to claim 4, wherein the gas condensate formed during quenching is recycled to the immersion chamber.
6. A method according to claim 5, wherein the gas condensate formed during cooling is recycled to the immersion chamber.
7. A method according to any one of claims 2 to 6, for stripping coke-oven liquor or the like, containing both bonded and free ammonia, wherein the free ammonia is first stripped from the aqueous fluid in the top part of the stripping column, whereas the solution freed from free ammonia is introduced into the immersion chamber and, after reacting with the calcium oxide produced during combustion, is conveyed to the top of the bottom part of the stripping column, whereas the evaporating liquids produced in the immersion chamber are used as stripping vapour and supplied to the column.
8. A method according to claim 1, wherein the resulting hot combustion gases are cooled in a waste-heat boiler to a temperature below the dew-point temperature, the calcium compounds in the form of dust are separated in a separator, and the dust is conveyed to a reaction container and brought in contact with an aqueous liquid to form a new reaction liquid.
9. A method according to claim 8, wherein the aqueous liquid is the liquid for treatment and the new liquid formed in the reaction container is supplied to the top of the stripping column.
10. A method according to claim 9, wherein the hot reaction gases leaving the separator are used in an indirect heat exchanger for pre-heating the aqueous starting liquid.
11. A method according to claim 8, wherein the aqueous liquid is a partlytreated liquid.
12. A method according to claim 11, for stripping ammonia from coke-oven liquor or the like, containing both bonded and free ammonia, wherein the free ammonia is first stripped from the aqueous liquid in the top part of the column, and the solution freed from free ammonia is introduced into the reaction container and the new reaction liquid formed in the reaction chamber is supplied to the top of the bottom part of the stripping column, whereas the reaction gases leaving the separator are introduced below into the bottom portion of the top part of the column, which bottom portion is not operated with lime.
13. A method according to claim 12, wherein the hot reaction gases from the dust separator are used in an indirect heat exchanger for pre-heating the waste-heat boiler feed water.
14. A method according to any one of claims 8 to 12, wherein the evaporating liquids formed in the reaction container are directly introduced into the evaporatingliquid line leading from the stripping column.
15. A method according to any one of claims 8 to 14, wherein the gas condensate produced during cooling in the waste-heat boiler is recycled to the reaction container.
16. A method according to any one of claims 8 to 15, wherein the effective mean gas velocity in the waste-heat boiler is 20 to 60 m/sec, preferably 30 to 50 mlsec.
17. A method according to any one of claims 1 to 16, wherein the reducing combustion is brought about at a temperature of between 800 and 1000"C and the resulting calcium compounds consist mainly of calcium oxide.
18. A method according to any one of claims 1 to 16, wherein reducing combustion is brought about at a temperature of 600 to 9000C and the resulting calcium compounds consist mainly of calcium sulphide.
19. A method according to claim 18, wherein the H2 to H20 ratio or the CO to
CO2 ratio is greater than 2 to 1.
20. A method of stripping ammonia from ammoniacal solutions substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19772705280 DE2705280C2 (en) | 1977-02-09 | 1977-02-09 | Process for stripping ammonia from solutions containing ammonia |
| DE19772722559 DE2722559A1 (en) | 1977-05-18 | 1977-05-18 | Stripping ammonia from liquors - by treating with lime in a stripping column and burning the spent lime sludge to regenerate it, for use with coke oven water |
| DE19772722419 DE2722419A1 (en) | 1977-05-18 | 1977-05-18 | Removal of ammonia from effluent water - by treating in a column with milk of lime, removing ammonia with a hot gas stream and burning the lime sludge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1558659A true GB1558659A (en) | 1980-01-09 |
Family
ID=27187114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB5013/78A Expired GB1558659A (en) | 1977-02-09 | 1978-02-08 | Methods of stripping ammonia from ammoniacal solutions |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS53102899A (en) |
| BR (1) | BR7800689A (en) |
| CA (1) | CA1109231A (en) |
| FR (1) | FR2380223A1 (en) |
| GB (1) | GB1558659A (en) |
| NL (1) | NL7801228A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005097680A1 (en) * | 2004-04-07 | 2005-10-20 | Western Minerals Technology Pty Ltd | Process for the regeneration and recovery of ammonia |
| US20220154646A1 (en) * | 2019-03-15 | 2022-05-19 | Mitsubishi Power, Ltd. | Ammonia decomposition facility, gas turbine plant equipped with same, and ammonia decomposition method |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES480724A0 (en) * | 1978-05-25 | 1980-11-01 | Gen Electric | METHOD FOR RECOVERING AMMONIA FROM A WATER CURRENT THAT CIRCULATES CONTINUOUSLY |
| JP2020147478A (en) * | 2019-03-15 | 2020-09-17 | 三菱日立パワーシステムズ株式会社 | Ammonia decomposition equipment, gas turbine plant with the same, ammonia decomposition method |
| CN112299513A (en) * | 2020-11-06 | 2021-02-02 | 内蒙古万众炜业科技环保股份公司 | Ammonia distillation and dephenolization coupling device and process for wastewater for semi-coke production |
-
1978
- 1978-02-02 NL NL7801228A patent/NL7801228A/en not_active Application Discontinuation
- 1978-02-03 BR BR7800689A patent/BR7800689A/en unknown
- 1978-02-08 JP JP1252878A patent/JPS53102899A/en active Pending
- 1978-02-08 GB GB5013/78A patent/GB1558659A/en not_active Expired
- 1978-02-09 CA CA296,748A patent/CA1109231A/en not_active Expired
- 1978-02-09 FR FR7803659A patent/FR2380223A1/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005097680A1 (en) * | 2004-04-07 | 2005-10-20 | Western Minerals Technology Pty Ltd | Process for the regeneration and recovery of ammonia |
| US20220154646A1 (en) * | 2019-03-15 | 2022-05-19 | Mitsubishi Power, Ltd. | Ammonia decomposition facility, gas turbine plant equipped with same, and ammonia decomposition method |
| US11702988B2 (en) | 2019-03-15 | 2023-07-18 | Mitsubishi Heavy Industries, Ltd. | Ammonia decomposition facility, gas turbine plant equipped with same, and ammonia decomposition method |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2380223A1 (en) | 1978-09-08 |
| CA1109231A (en) | 1981-09-22 |
| BR7800689A (en) | 1978-11-28 |
| FR2380223B1 (en) | 1983-07-29 |
| NL7801228A (en) | 1978-08-11 |
| JPS53102899A (en) | 1978-09-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |