GB190825535A - Process of, and Apparatus for, Obtaining Nitrogen from the Air. - Google Patents

Abstract

25,535. Blagburn, C. Nov. 27, 1907, [date applied for under Section 91 of Patents &c. Act, 1907]. Nitrogen is obtained pure by directing a stream of air into contact with sulphur in excess, at not less than the ignition temperature, and conducting off the resulting gases, while removing the unoxidized excess of sulphur and the products of combustion. In the apparatus described, sulphur is fed into a combustion chamber 1, having a slightly sloping bottom 4, through a passage 2 provided with a cover 3, and is initially or continuously heated by means of a fire-box underneath. Air is drawn by suction, either through a pipe 8 into a heating-chamber 5, heated by the burning sulphur under its sloping bottom 6, and thence through pipes 9 on to the sulphur in the combustion chamber 1, or else through the charging-opening 2. From the narrow outlet 7 of the furnace the gases pass through an intensely hot up-take 10 wherein any unburnt oxygen combines with the excess sulphur vapour. The gases then pass cown one subliming-chamber and up another, the excess of sulphur being deposited therein. From the top of the second subliming - chamber the gases pass through three successive washing-towers of different kinds, wherein water is sprayed from the top. Sulphurous acid collects at the bottom of each tower in a liquid seal. Ammonia is next removed by bubbling the gases from a perforated pipe through water or other suitable liquid in a washvessel, whence the gases pass to a second perforated pipe at the bottom of another wash-vessel, half-filled with caustic potash solution to remove any remaining trace of sulphurous acid or carbonic acid gas. If dry nitrogen is required, as for use as a preservative, another vessel half - filled with calcium chloride is interposed between the last wash-vessel and the pump which draws the air into the furnace and through the various chambers, and which now forces the resulting nitrogen into a suitable receiver. In order to economize the caustic potash and calcium chloride, a by-pass pipe between the third washing-tower and the pump, and suitable valves are provided. This passage is used until the gas passing from the pump is found by testing to be sufficiently free of oxygen. The last trace of oxygen can be removed from the nitrogen by leaving iron filings in contact with it in the receiver for a few days.