GB427967A - Improvements in the manufacture of hydrogen - Google Patents

Abstract

<PICT:0427967/III/1> <PICT:0427967/III/2> In manufacture of hydrogen from silicon and a caustic alkali as described in Specification 399,110, wherein the acid silicate is produced, means are provided whereby the hot solution formed is removed from the reaction vessel so that the hydrogen may be withdrawn in a relatively cool condition. A pressure vessel 2, Fig. 3, is provided with a flange 4 to which is bolted a cover 5, a gasket 6 serving to render the cover gas tight. Carried in the interior is a series of perforated containers 11, 12, 13, the lowest of which contains a mixture of powdered silicon and caustic soda, the others being filled with granulated silicon. Water is added through a tube 9 in the cover, the reaction taking place in a few minutes and being of very short duration. After the completion of the reaction, a valve 17 in a pipe 15 is opened, the pipe dipping down to the bottom of the basket 11 and removing therefrom under the pressure of the hydrogen, the liquid contents of the vessel 2. One or more generators 2 may be mounted on a vehicle provided with a crane for operating the vessels 2, the gas produced being withdrawn by valved pipes 18 and conducted to a purifying vessel. In a modified form, the reaction may be rendered partially or wholly continuous, the vessel 2 being adapted to receive a metallic holder 24, Fig. 5, provided with perforated shelves 25, the lowest compartment serving to contain a mixture of caustic soda and silicon which functions as the starting charge, the other compartments being filled with granulated silicon. Water to start the reaction is introduced in the manner described with reference to Fig. 3, gas being withdrawn by a pipe 18 and the liquid contents by a pipe 5. To render the process continuous, a solution of caustic soda is pumped on to bubble trays 32 by a pipe 26, the solution being raised to the necessary temperature by the steam and gas generated by the starting reaction. Additional supplies of silicon may be added by a device consisting of a chamber having entrance and exit valves. In a second modification, an oil reservoir is provided so that the pump does not deal directly with the caustic soda solution.