GB981275A - Method of, and apparatus for, obtaining pure hydrogen from gas mixtures - Google Patents

Abstract

Pure hydrogen is separated from hydrogen-containing gas mixtures, which are produced at high temperatures from hydrogen-containing compounds in a process characterized in that at least a considerable part of the heat contained in the gas mixture is utilized to pass the mixture at an elevated temperature through a foil of a metal of the platinum group. If the dissociated gas is produced for example by the catalytic decomposition of ammonia at temperatures of 600-900 DEG C. the dissociated gas is passed directly in a hot condition to the hydrogen-pervious separating wall which seals off the space for receiving the diffused pure gas. Hydrocarbons and alcohols can be decomposed by heating with coated vapour and the carbon monoxide thus produced further reacted with water vapour to produce carbon dioxide and additional hydrogen. The mixture of carbon dioxide, water vapour and hydrogen then produced is subjected to preliminary purification at low temperatures characterized in that, a heat exchanger is connected in line ahead of the equipment for absorbing or precipitating the readily removable constituents of the gas, i.e. carbon dioxide and water vapour respectively, in which the mixture flowing from the decomposition chamber transfers a considerable part of its heat content to the mixture passing in the cooled condition from the purification equipment, which latter mixture is heated to an elevated temperature and thereby passed to the diffusion cill. The diffusion of hydrogen is accelerated by a difference in pressure between the inlet and receiving compartments. If the hydrogen compound which is split up to produce hydrogen is delivered in pressure chambers, the pressure stored therein can be utilized to provide the pressure in the dissociation chamber and the inlet chamber of the diffusion cill. If liquid hydrocarbons are converted into hydrogen-containing mixtures, the evaporation process to which the initial material is subjected can be utilized to generate pressure in the plant.ALSO:Pure hydrogen is separated from hydrogen-containing gas mixtures, which are produced at high temperature from hydrogen containing components, in a process characterized in that at least a considerable part of the heat contained in the gas mixture is utilized to pass the mixture at an elevated temperature through a foil of a metal of the platinum group. If the dissociated gas is produced for example by the catalytic decomposition of ammonia at temperatures of 600-900 DEG C. the dissociated gas is passed directly in a hot condition to the hydrogen-pervious separating wall which seals off the space for receiving the diffused pure gas. Hydrocarbons and alcohols can be decomposed by heating with water vapour and the carbon monoxide thus produced further reacted with water vapour to produce carbon dioxide and additional hydrogen. The mixture of carbon dioxide, water vapour and hydrogen thus produced is subjected to preliminary purification at low temperatures characterized in that a heat exchanger is connected in line ahead of the equipment for absorbing or precipitating the readily removable constituents of the gas, i.e. carbon dioxide and water vapour respectively, in which the mixture flowing from the decomposition chamber transfers a considerable part of the heat content to the mixture passing, in the cooled condition, from the purification equipment, which latter mixture is heated to an elevated temperature and thereby passed to the diffusion cell. The diffusion of hydrogen is accelerated by a difference in pressure between the inlet and receiving compartments. If the hydrogen compound which is split up to produce hydrogen is delivered in pressure chambers, the pressure stored therein can be utilized to provide the pressure in the dissociation chamber and the inlet chamber of the diffusion cell. If liquid hydrocarbons are converted into hydrogen-containing mixtures, the evaporation process to which the initial material is thereby subjected can be utilized to generate pressure in the plant.