GB610546A - Generation of acetylene or other gas - Google Patents

Abstract

<PICT:0610546/IV(b)/1> <PICT:0610546/IV(b)/2> Acetylene or other gases are prepared by feeding together a solid, e.g. calcium carbide, and a liquid into a generating chamber, regulating the rate of liquid feed in automatic response to variations in the temperature of the gas so that the amount of liquid fed is sufficient to react effectively with the solid and to absorb the heat of reaction, and modulating the amount of liquid fed at the control temperature in automatic response to changes in the consistency of the charge so that less liquid is fed when the charge becomes heavier and more when the charge becomes lighter, to compensate for changes in the characteristics of the solid. The rate of feed of solid is regulated automatically in response to changes in a selected condition such as the demand for gas, gas pressure or the maintenance of a constant rate of gas flow. In the preparation of acetylene, the control point is within the range 195 DEG to 210 DEG F., and may be modulated as above by an amount up to 10 DEG F. The apparatus may be of the same general type as that described in Specification 559,198 and includes a generating unit consisting of superimposed drums 15, 30 and 40, a carbide feed unit consisting of the hoppers 90, 91 and 92, a gas off-take 50 and scrubbing and cooling towers. The valves between the carbide feed hoppers 90, 91 and 92 are arranged so that one is closed while the other is open in order to prevent escape of acetylene from the generator, and the opening and closing of the valves and the operation of the supply conveyer 89 are arranged to respond automatically to the level of the carbide in hoppers 91 and 92, and to a selected condition such as the gas pressure or the demand for gas. Associated with the hoppers are pipes which withdraw nitrogen from the hopper which is being filled and supply nitrogen to the hopper which is being emptied, the valves for the nitrogen pipes being automatically controlled in step with the carbide supply. Water supply to the generator is controlled by a valve 227 which is made automatically responsive to temperature changes in the offtake 50. A temperature-responsive device 226 consisting of a tube filled with liquid is connected by tubing 229 with a bellows 228 which normally tends to hold the valve 227 open. The valve stem terminates in a plate 237 located between the bellows and a spring 230 which tends to close the valve. Accordingly, an increase in the temperature in the offtake 50 opens the valve further and increases the supply of water, and vice versa. In order to modulate the supply independently of the temperature and in response to changes in the consistency of the charge, a solenoid 235, which becomes energized when the current drawn by motor 12 driving the agitator 17 reaches a certain level, is connected by a spring 233 to the lever 216 in such manner that the operation of the solenoid opposes the operation of the bellows 228 and raises the control temperature in the offtake 50. The amount of water supplied from the cooling tower to the scrubbing tower and the amount of fresh water fed to the cooling tower are automatically controlled by liquid level indicators in the scrubbing and cooling towers, respectively. Means are provided for automatically discharging the hydrate at 45 when the level of the hydrate in 40 p reaches the baffle 248 and causes the gas pressure in 40 and in pipe 251 to rise and close the switch of motor 44b.