Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/04—Purification or separation of nitrogen
  • C01B21/0405—Purification or separation processes
  • C01B21/0411—Chemical processing only
  • C01B21/0422—Chemical processing only by reduction
• • 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
  • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
• • 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
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B23/00—Noble gases; Compounds thereof
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
  • C01B3/56—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K3/00—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
  • C01B2203/042—Purification by adsorption on solids
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
  • C01B2203/0465—Composition of the impurity
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2210/00—Purification or separation of specific gases
  • C01B2210/0043—Impurity removed
  • C01B2210/0045—Oxygen

Definitions

• This invention relates to a method for removing oxygen from an oxygen-containing gas comprising contacting said gas with finely-dividedcoal at a temperature of up to 450 C. and not exceeding the softening temperature of thecoal.
• Extracted nitrogen that is substantially free of oxygen is of great utility for many commercial operations. .Such oxygen-free nitrogen has been comparatively difficult to attainheretofore. It is known, for instance, that socalled Frankl apparatus can be employed in the preparation of extracted nitrogen and oxygen from air wherein the extracted nitrogen contains small amounts of oxygen, to wit, not much less than 2% by volume. By a, sharper separation the oxygen contentmay be reduced to 0.02- 0.05% by volume. This oxygen -content may be still further reduced but only by expensive methods which, for reasons of economy, are unsuitable.
• a constant eifort has been maintained to produce gas, in substantially oxygen-free form so that it may be utilized commercially.
• Nitrogen in theoxygen-free form possesses great utility but it should be stressed that this invention contemplates the extraction of oxygen from other gases as well. It has now been found that oxygen can be removed from a gas'if the gas is brought into contact with finely-divided coal at a temperature which does not exceed 450 C. and which is always kept below the softening temperature in cases where a softening coal is employed. According to the present inventioni the coal is caused to combine with the oxygen in which process the coal is oxidized.
• finely divided when used herein, is meant grain sizes not greater than 5 mm.
• the grain size is preferably between 0.5 and 3.0 mm. It is preferred to employ the process in cases where the oxygen concentration does not exceed by volume of the 'gas, since with higher oxygen con-ventrations the heat developed and the carbon monoxide for-med increase. The best results are achieved when-the oxygen concentration does not exceed about 3%.
• a small grain size e.g., a diameter of about 0.5-3.0 mm
• a large surface area of the coal particles is obtained, by which the contact between coal and gas is promoted.
• a smaller diameter of grain size can be feasibly used, even as low as a diameter of 0.1 mm.
• a coal not softening below 450 C. is utilized as heretofore noted.
• the treatment can be carried out at a temperature of from 360 to 380 C. and high gas velocity can be employed, for example, 50- 60 liters of gas per liter of coal per hour, the coal remaining active until it is nearly all used up and practically only the ash remains. It should be appreciated that various gas velocities can be utilized depending upon the prevailing operating conditions. If a bituminous coal softening at about 320 C. is used caking of the coal particles and tar formation can be avoided by carrying out the treatment at a temperature of from about 270 to 290 C.
• Atmospheric pressures rnay be employed in the subject process, but it can be appreciated that "super and-sub atmospheric pressures would also be operative.
• the actual volume. of coal'to which the gas is exposed can be varied depending upou'the volume of gas intended tobe treated per stipulated period-of time. It can be appreciated that the greater the gas velocity the greater the amount of coal necessitated.
• the process according to the invention may be applied for removing oxygen from all kinds of gases containing a small amount of oxygen, such as nitrogen, carbon monoxide, hydrogen and ;argon. In this manner the oxygen content may be reduced to less than 0.001% by volume.
• the invention makes it possible to prepare'in a simple manner gases in which practically no oxygen is left, so that new possibilities arise for the application of these gases.
• the amount of oxygen contained in these gases had always presented difficulties in many applications.
• nitrogen is also obtained, which, however, contains from 1 to"5% by volume and mostly from 2 to 3% by volume of oxygen. This in many cases precludes the useful application of this by-product.
• gases purified according to the invention are also suited for analytical purposes.
• the invention enables a direct gravimetric determinationof moisture in coal-to be carried out with the help of nitrogen from which the oxygen has been extracted in the manner according to the "invention, by "heating a certain amount of coal to -110 C. while passing the nitrogen through the coal, and determining the amount of water carried off by the nitrogen.
• the loss in Weight of the coal must correspond with this amount of water. If in this determination of moisture, oxygencontaining nitrogen be employed, the results obtained are always deceptive as a result of the oxidation of the coal, in which process water is formed.
• this simple method of determining the moisture content can now be carried out with nitrogen treated in the manner according to the invention. It is advisable that the removal of the oxygen be carried out as a preliminary treatment of the nitrogen, before the moisture content is determined. Naturally, the nitrogen pre-treated in this manner has to be dried.
• Another possibility arising from the invention is the employment of nitrogen as an inert medium in the polymerization of lactams, such as caprolactam, to form polymerization products, from which polyamide-filaments can be spun or from which articles can be made, for instance by injection moulding.
• lactams such as caprolactam
• oxygen-containing nitrogen is employed as the reaction medium, yellow colored polymerization products are obtained from which filaments with good and constant mechanical properties cannot be spun. Moreover, re peated breakage of the filaments occurs in spinning such products.
• water gas which mostly contains 0.3-0.7% by volume of oxygen, can be purified in the manner according to the invention and thus be made more suitable for syntheses in which catalyst are employed.
• a vertical cylindrical vessel having a diameter of 20 cm. and a height of 3 m. was filled with finely-divided meagre coal (percentage of volatile matter: 11-14) having a grain size of from 0.5 to 1.5 mm.
• meagre coal percentage of volatile matter: 11-14
• nitrogen was led upwards which had an oxygen content of 0.02% by volume.
• the velocity of the gas current amounted to 5-6 m. per hour.
• the temperature in the vessel was kept at 300-350 C., the nitrogen being pre-heated to about 300 C. prior to entering the vessel.
• the nitrogen leaving the vessel was contaminated by volatile components issuing from the coal. After the nitrogen had been passing through the vessel for about half an hour a continuous current of purified gas was obtained, which was further passed through a vessel filled with silica gel. Only 0.001% by volume of oxygen was left in the purified nitrogen.
• Example II In a manner similar to that described in Example I, nitrogen having an oxygen content of 0.14% by volume was brought into contact with anthracite (grain-size 0.5- 1.5 mm.) at a temperature of 360-380 C. The oxygen content of the nitrogen was found to have been reduced to 0.0008% by volume.
• Argon containing 0.03% by volume of oxygen, was treated in a similar manner, as a result of which its oxygen content decreased to 0.0009% by volume.
• Example III In a manner similar to that described in Example I, nitrogen having an oxygen content of 0.039% by volume was brought into contact with finely-divided semi-bituminous coal (percentage of volatile matter: 17) having a grain size of from 0.5-1 mm. The temperature of the coal was kept at 270-280 C. The oxygen content was reduced to 0.0008% by volume.
• Nitrogen having an oxygen content of 1.6% by volume was contacted with finely-divided bituminous coal (percentage of volatile matter: 25.3) having a grain size of from 1 to 2 mm.
• the velocity of the gas was 5-6 m. per hour.
• the temperature of the coal was maintained at 4550 C. with the help of a heating jacket, while the nitrogen was not pro-heated.
• the oxygen content was found to have decreased to 0.0011% by volume.
• a process for removing oxygen from oxygen-containing gas, wherein the oxygen content of the gas is not more than about 3% by volume of the gas comprising contacting said gas with finely divided coal at a temperature of from room temperature up to about 60 C. and not exceeding the softening temperature of the coal, the primary oxidation product of said process being solid oxidized coal.
• a process according to claim 1 wherein the grain size of the coal is not less than about 0.1 mm. and not more than about 5.0 mm.
• a process according to claim 2 wherein the grain size of the coal is not less than about 0.5 mm. and not more than about 3.0 mm.
• a process for removing oxygen from oxygen-containing gas, wherein the oxygen content of the gas is not more than about 3% by volume of the gas comprising contacting said gas with finely divided coal at a temperature of from room temperature up to about 60 C. and not exceeding the softening temperature of the coal, the primary oxidation product of said process being solid, oxidized coal, said oxygen-containing gas consisting essentially of nitrogen containing less than about 3% by volume of oxygen.

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• Chemical & Material Sciences (AREA)
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Citations (8)

• 0
  • BE BE16335D patent/BE16335A/xx unknown
  • NL NL75333D patent/NL75333C/xx active
  • BE BE516335D patent/BE516335A/xx unknown
• 1952
  • 1952-12-12 US US325693A patent/US2962343A/en not_active Expired - Lifetime
  • 1952-12-15 GB GB31706/52A patent/GB728530A/en not_active Expired
  • 1952-12-15 FR FR1067708D patent/FR1067708A/fr not_active Expired
  • 1952-12-18 CH CH313762D patent/CH313762A/de unknown

Patent Citations (8)

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