786
MODERN GASWORKS PRACTICE
When the vessel A is used for making producer gas or semi-water gas, the producer gas may enter the retort C through the pipes E and G or pass through the pipes F for any desired purpose.
Robinson’s Mixed Gas Plant
A diagrammatic illustration of Robinson’s mixed gas plant is shown m Fig. 473. Ordinary horizontal retorts of the “ through ” type are shortened, and terminate in a water-gas generator. The generator, which occupies the same position in the setting as the customary producer, is operated on the principle of “ run ” and “ blow.” The blow gases pass into the combustion chamber, around the retorts, and finally travel out of the setting by way of the stack valve. The “ blue ” water gas made during the run passes through, the retorts above the coal charge and scavenges
Fig. 474.—Knight and Siddall’s Combined Plant.
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out the coal gas, the mixture travelling direct to the liydranlic main. The in-ventor states that by modifying the conditions of gas-making it is possible to vary the quality of the final mixture obtained between the limits of 280 and 460 B.Th.U. per cubic foot. Only ash and clinker are removed from the plant, and it is possible to obtain 18 million gaseous B.Th.U. per ton of coal em-ployed.
Knight and Siddall’s Combined Plant
This plant, as made by R. & J. Dempster,1 consists, in one form, of a generator (A), Fig. 474, operated on the water-gas principle. A second chamber (B) erected within the same shell con-tains a vertical retort (C) provided with. two bottom doors. Air is blown into the generator (A), the blow gases travelling by way of an external conduit (D) into the chamber (B), being burnt around the vertical retort and passing out. by the stack valve. In this way the coal in the retort is partially carbonized
but, during the run, when steam is admitted to the generator, the water gas produced is partly burned in the chamber (B) until sufficient heat is obtained. At the end of this operation the water gas, instead of being burned, passes through the chamber (B) into a seal (E), and thence into the base of the vertical retort. Distillationis, therefore, carried out continuously.
1 E.P. 18,076/1920.