Journal . is in-troduced (as a matter of practice the exhaust steamfrom the engine is used). It is at this point that the portion of the gas whichis purified in our plant is drawn off. The gas entering the scrubbers contains the follow-ing removable impurities :—Ammonia, sulphurettedhydrogen, carbonic acid, and carbon bisulphide, and,in addition, hydrocyanic acid and oxygen, which,though they can hardly be called impurities, areabsorbed in the scrubbers, and play an importantpart in the process. The quantities of these substances are, as mightbe expected, somewhat variable, as will be seen fro
Journal . is in-troduced (as a matter of practice the exhaust steamfrom the engine is used). It is at this point that the portion of the gas whichis purified in our plant is drawn off. The gas entering the scrubbers contains the follow-ing removable impurities :—Ammonia, sulphurettedhydrogen, carbonic acid, and carbon bisulphide, and,in addition, hydrocyanic acid and oxygen, which,though they can hardly be called impurities, areabsorbed in the scrubbers, and play an importantpart in the process. The quantities of these substances are, as mightbe expected, somewhat variable, as will be seen fromthe following table :— Ammonia 0) to 05 per cent, by volume. .?sulphuretted hydrogen .. 10 to 18 ,, „ Carbonic acid 1*5 to 28 ., ,, Hydrocyanic acid 0*1 — ,, „ Oxygen DO to 08 The volume of the carbon bisulphide is extremelysmall, only forming two or three hundredths per the crude gas. The carbonic acid and sulphuretted hydrogengenerally amount to about four per cent, of thecrude pure a a s Thick lines denote liquor pipes. A minute quantity of caustic soda solution ismixed with the liquor in the still for the purpose ofdecomposing the fixed salts of ammonia. The liquor,on arriving at the bottom of C, is completely freefrom ammonia, and, after cooling, is pumped to atank placed over scrubber A, and is used again forwashing the gas. The whole series of operations is perfectly con-tinuous : the only materials used for the purificationof the gas are ammonia and water, which are broughttogether in the scrubbers to combine with andabsorb the impurities of the gas, and are then, afterbeing freed from these impurities by heat, separatedfrom each other by distillation, to be again broughttogether in the scrubber, and so on. We will now consider more in detail the changesundergone by the gas and liquor in the variousstages of the process. ll RE II ATIOX OF THE O V-. The crude gas made in the retorts passes firstthrough the condensers and a Livesey washer, thelatt
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
