Modern Gasworks Practice

00 MODERN GASWORKS PRACTICE through the chequer work to tlie exit valve. When the proper temperatures have been attained the air blast is tiirned off and steam is turned on through, the ch.equ.er brick-and the iron chamber. The resulting hydrogen and remaming steam may be led directly away or be passed dowuward through the incandescent fuel and tlien led away. In the first case the tmdecomposed portion of the steam mixed with the hydrogen can be Condensed out. In the second case the uncondensed portion of the steam mixed with the hydrogen will be decomposed on passing through the incandescent fuel into hydrogen and carbon monoxide, which will become mixed with. the hydrogen produced in the iron chamber. In each case steam or liquid hydro-carbon or both. may be injected directly into the mass of incandescent fuel indepen-dently of tlie steam admitted to the iron chamber, and be mixed with hydrogen produced in that chamber in. order to vary the constituents of the resulting gas to suit requirements. By admitting air to the bottom of the cbequer-brick chamber carbon monoxide in the gases entering that chamber from the iron chamber can. be burned to form carbon dioxide before being discharged into the atmosphere, and the resulting heat utilized to heat the chequer-brick chamber preparatory to passing steam to the iron ■chamber. H. E. Smith 1 proposes to modify water-gas plant of the double generator type (see K. and A. plant) so as to produce a gas with variable proportions of hydrogen and carbon monoxide. In many processes which depend upon catalytic action it is an advantage to have water gas with. varying proportions of hydrogen and carbon monoxide. For instance, in the process for the purification of coal gas from sulphur Compounds where the surfaces of the catalyzing agent are liable to be covered with. deposits, the presence of water gas of suitable composition greatly prolongs the life of the material used. The twin generator plant, blown in parallel and run in series, is adapted to produce a gas containing a high percentage of CO, by the installation of a separate fireclay-lined chamber arranged between the two twin generators and provided at the top with charging hopper and at the bottom with discharging hopper. This chamber is so arranged that the walls are heated by the products of combustion during the blowing period, and is also provided with a division wall so tliatthe hot gas leaving the first generator passes up at one side and down, at the other. The chamber is filled. up with limestone of suitable quality, which, when heated to the necessary temperature and brought in contact with the hot water gas from the first generator, will evolve C02, which gas will join the hot water gas from the first generator and be reduced to CO in its passage through the second generator. In. order that the neces-sary amount of contact may be secured, dampers may be provided in the division wall to short-circuit the stream of gas and vary the contact with the limestone as needed. Where a high percentage of hydrogen is required and a low percentage of CO, the plant is operated in. the ordinary manner for producing “ blue ” water gas, but a ' 1 B.P. 116,582/17.