Patent GB-189913771-A (GB)
Title: Method and Apparatus for Producing Alkali and Chlorine.
Inventor: NAEF PAUL
Filed: 1899-07-04
Granted: 1900-10-04
Abstract: 13,771. Naef, P. July 4. Chlorine.-Alkali is produced by the ammonia process, the process being so arranged that all the chlorine is obtained free, and all the reagents employed are obtained in a condition for reuse. The principal vessels employed are rotating cylinders A<1>, A, B', B, C, D, E, E', mounted upon rollers 1. The cylinders A', A, B<1>, B, and C are constructed as described in Specification No. 13,771A, A.D. 1899, [Abridgment Class Acids, alkalies, &c.], namely with cooling- pipes 2, radial perforated agitating partitions, longitudinal lifters, and cross partitions having openings so as to cause the gases to take a zig-zag direction. Brine enters the absorbing-cylinder A' by the tube 5, while waste gases enter at the other end by the tube 7 to be absorbed, any unabsorbed gases escaping at 6. The brine passes by a tube 8 to the vessel A, which receives ammonia at the other end by the tube 9. The unabsorbed ammonia passes by the tube 10 first to a gasheater D<1>, and then to the ammonia-regenerating cylinder D, from which it passes back to the cylinder A. The saturated brine passes by a tube 11 to the settling-tank 12, and afterwards by a tube 19 to the cylinder B', in which it is treated with cooled carbonic acid entering by the tube 18 from the cooler B'. The carbonic acid is obtained in a kiln B<5>, into which limestone is charged by a hopper 30 and a conveyer 31. To obtain carbonic acid free from nitrogen, hot carbonic acid is led into the kiln through a tube 37, annular channel 34, and openings 33, and is withdrawn through the openings 35 and annular channel 36, and is passed by a fan 39 to a gas heater B<6>, and then back to the kiln, thus keeping up a constant circulation. The carbonic acid, produced by the action of the hot gas is cooled by the limestone in the upper part of the kiln, and escapes by a tube 13 to a washer 14, and thence may pass by a tube 14" to a gas cooler B<3>, tube 16, and cylinder B, and by the pipe 15 to the cooler B<4>; or the gas may be sent by a fan 29 through a cooler B<7> and the settling-vessel B<2> for collecting bicarbonate, and thence by the tube 14<c> to join the tube 14<a>. The brine passes from the cylinder B' to the settling-vessel 21, from which it is carried by a pump 28 to the cylinder B<2>. It next passes to the settling-vessel 22, and by the tube 17 to the cylinder B. Any unabsorbed gases from the cylinder B<1> pass to the cylinder A<1>. All the bicarbonate having been separated in the vessels B<1>, 21, B<2>, 22, B and in further settling-tanks 24, 25, the solution flowing away consists simply of ammonium chloride containing some sodium chloride. It passes to the cylinder C, in which it is cooled down, by the circulation of a cold inert gas from the cooler C<1> by means of the tubes 41, 42 and fan 43 so as to separate solid ammonium chloride. The liquor holding the ammonium chloride in suspension is run off to a settling-tank 47, and then to a filter 48. The filtrate is returned, after saturation with solid salt, to the cylinder A' through the pipe 5, while the solid chloride is placed in a hopper 49, and magnesia is placed in a hopper 50. The two bodies are discharged by screws, and delivered mixed into the cylinder D, in which the mixture is treated with the hot inert gas from the heater D'. Ammonia is recovered, and is led back to the cylinder A. The magnesium oxide and chloride left pass to a hopper 51, and thence to the cylinders E. E'. Air enters a heater E<2> through a tube 57, and the hot air passes by a tube 58 to the cylinder E<1>. The heated air and chlorine given off pass to a gas-heater E<2>, and thence to the upper cylinder E by the tube 60. From the cylinder E strong chlorine is evolved, and is led away through a tube 61. The magnesia discharged from the cylinder E' to the hopper 54 is raised by an elevator 55, and carried by a conveyer 56 to the hopper 50 for re-use. The cylinders E, E<1> may be constructed as described in Specification No. 30,496, A.D. 1897.