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
• • 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
  • B01D53/508—Sulfur oxides by treating the gases with solids
• • 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
  • B01D53/68—Halogens or halogen compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/86—Catalytic processes
• • 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
  • B01D53/8603—Removing sulfur compounds
  • B01D53/8609—Sulfur oxides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
  • B01D53/86—Catalytic processes
  • B01D53/8621—Removing nitrogen compounds

Definitions

• the invention relates to a method for eliminating pollutants from exhaust gases.
• the mixture is used, for example, in the form of brown-black, hard, porous, 2-3 mm large grains in CO filters of gas masks so that they can be used in rooms contaminated with gas from carbon monoxide.
• the carbon monoxide passing through this mixture is converted catalytically into carbon dioxide at room temperature.
• the invention is based on the object of proposing a method with which pollutants, in particular fluorine, but also sulfur dioxide and sulfur trioxide, can be removed from exhaust gases without great expenditure on apparatus.
• the method according to the invention should also be able to be used to remove carbon monoxide by oxidation to carbon dioxide in exhaust gases.
• fillers known per se are coated with a slurry which reacts with the pollutants, contains a calcium compound or contains a mixture of metal oxides and serves as a catalyst, to which small amounts of methyl cellulose are added as binders, and coated them
• Filling bodies are fed to a container through which exhaust gases flow, via an exhaust gas line, the coated filling bodies being shaped and loosely in the container are filled up so that the exhaust gases can easily flow through them.
• the fillers coated with a slurry containing a calcium compound and loosely filled into a container are used in an exhaust pipe of an industrial plant for the removal of, in particular, fluorine, sulfur dioxide and sulfur trioxide.
• the fillers coated with the mixture of metal oxides and serving as a catalyst and loosely filled in the container are inserted into an exhaust gas device for the oxidation of carbon monoxide.
• the advantages achieved by the invention consist essentially in the fact that the method according to the invention can be carried out inexpensively without a large apparatus structure and thus less work and that the use of known, saddle-shaped fillers means that the exhaust gas flow is flat over the entire diameter of the container (e.g. with a ceramic sleeve ) is distributed so that there is already a complete reaction of the exhaust gases in the lower part of the container with the coating of the packing and, as a result, the exhaust gas leaves the ceramic filter completely cleaned.
• the filling bodies being filled up loosely in the container, a sufficiently free volume between the filling bodies is achieved, so that the required flow rate is possible without the use of a fan.
• the saddle-shaped packing also offer a very low flow resistance in their packing position, so that the use of fans is also eliminated for this reason.
• the invention makes it possible to wash off the products obtained in the reaction with the calcium compound without any particular complex separation processes, so that these chemical industries are available again.
• the process according to the invention has the advantage that it enables the very toxic carbon monoxide gas to be removed catalytically by oxidation in carbon dioxide in a simple manner and on a technically larger scale.
• iron (III) rhodanide was chosen as the indicator because this compound has a deep red color and its iron is chemically bound in the presence of fluorine in the flue gas, which leads to the decolorization of the indicator.
• this indicator with a pH of about 1.5, a second one with the same composition was produced, but which had a pH of about 2.5, in order to avoid the strong carbon dioxide elimination when the first indicator reacted with the calcium carbonate counteract.
• the first indicator with a pH of about 1.5 was made from iron chloride FeCl 3 .6H 2 O with a mol. of 270.3 and ammonium thiocyanate NH 4 SCN with one mol. made from 76.1. These two connections react as follows:
• the second indicator with a pH-Wart of 2.5 was made from iron chloride FeCl 3 .6H 2 O with a mol. of 270.3 and potassium rhodanide KSCN with one mol. of 97.1. These two connections react as follows:
• the varauch was stopped after 12 minutes and the usability of the indicator used was determined.
• the container with the hydrofluoric acid was weighed back, minimal consumption of hydrofluoric acid was found, which led to the conclusion that only the indicator had reacted with the hydrofluoric acid.
• Example 3 Calcium bentonite and calcium carbonate were used as calcium compounds in this experiment.
• the mix approach was as follows:
• the dried, coated packing elements were refilled into the absorption tube up to a height of 90 cm and then used in the apparatus.
• the balanced container with the hydrofluoric acid was placed as before in the lower 90 ° elbow. After switching on Abzugskana.l and hair dryer, the observation values listed in Table III were obtained.
• Example 1 after 12 min 50 cm decolorization
• Example 2 after 12 min 35 cm decolorization
• Example 3 after 24 min 10 cm decolorization
• Example 4 In order to improve the test result even more, only calcium carbonate was used for coating the saddle-shaped packing. For better adhesion of the coating to the packing, a little methyl cellulose in a ratio of 1: 200 to the water content was added as a binder. To counteract the reaction of indicator with calcium carbonate, the second indicator with a pH of 2.5 was used in this experiment. The mix approach for this experiment was as follows:
• the coating weight is lower.
• the dried, coated packing bodies were filled up to a height of 90 cm as before into the absorption tube, the container was weighed with the hydrofluoric acid and placed in the 90 ° elbow. After switching on the extraction duct and hair dryer, the observation values given in Table IV are obtained.
• Example 5 In order to further improve the test result obtained from Example 4, the following mixture was made:
• the dried, coated packing was placed in the absorption tube and then inserted into the apparatus.
• the hydrofluoric acid was weighed out with the container as before. After switching on the ventilation duct and hair dryer, the observation values listed in Table V were obtained.
• the white zone had a length of 8 cm, only in this Zone Ka lzi formed around u u id.
• the overlying filler bodies had not come into contact with fluorine, which revealed an examination of the filler bodies after they had been poured out.
• X-ray diffraction revealed that fluorine had not passed the decolorization zone.
• a sample was taken from the white zone and another from the packing elements above.
• the X-ray diffraction pattern clearly showed reflections of calcium fluoride and besides, in a weakened form, reflections of calcium carbonate, from which it could be concluded that not all of the calcium carbonate was present in this zone either. with f luor react Ie rI hall e. this zone was therefore able to dazzle even more.
• the air led into the exhaust duct was examined for hydrogen fluoride using a Dräger tube.
• the scale of the tubes ranged from 1.5 to 15 ppm HF. Despite repeated measurements, no discoloration of the tubes was found , which showed that there was no longer any hydrogen fluoride in this air, so that it had been completely absorbed by the coating of the filling bodies.
• the amount of CaCO 3 required for this was 4784.9 g
• a volume of 1m 3 of coated, saddle-shaped packing material could be produced within 24 days bind all of the fluorine in the flue gas analysis given above, for which the specified volume of the packing would have to be coated with about 113 kg of calcium carbonate.
• known, saddle-shaped fillers are coated with a known mixture consisting of metal oxides, serving as a catalyst, together with a small proportion of methyl cellulose, whereby according to one embodiment of the invention, methyl cellulose is used as a catalyst, which consists of metal oxides Mixture is preferably added in a ratio of 1: 100.
• the coated packing elements are held in a container through which exhaust gases can flow and which, according to a further development of the invention, can be closed on both sides by a wire mesh.
• a container is inexpensive to manufacture and, with the coated, saddle-shaped packing elements, can easily be arranged in an exhaust gas device, for example in an exhaust pipe of heating systems or in an exhaust pipe of motor vehicle engines.
• the packing elements coated with metal oxides and the packing elements coated with the slurry containing a calcium compound must each be kept in separate filling devices so that the fully reacted calcium coating on the packing elements can be washed off and their reaction products can be collected for reuse. and that the coating consisting of metal oxides, which is applied to the packing and serves as a catalyst, is not consumed and is therefore available for further oxidation of the carbon monoxide.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Health & Medical Sciences (AREA)
• Biomedical Technology (AREA)
• Analytical Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Treating Waste Gases (AREA)

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Citations (5)

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• 1981
  • 1981-06-05 DE DE19813122349 patent/DE3122349A1/de active Granted
• 1982
  • 1982-06-05 WO PCT/DE1982/000121 patent/WO1982004406A1/en not_active Application Discontinuation
  • 1982-06-05 EP EP19820901839 patent/EP0080491A1/de not_active Ceased

Patent Citations (5)

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