Page:The New International Encyclopædia 1st ed. v. 05.djvu/160

* COKE. 128 COKE. then returning these gases to be burned in the flues to licat the ovens. The principal defect of tliese ovens was the failure to proixirtiou the several parts to the quality of coal to be coked. This mistake was corrected by Carv6s of France in the Knab-Carv&s oven of 1873, which has proved a model for later ovens. Subsequent im- provements were made by Albert Huessner in Germany and G. Siebel in France, in 1881. Coke produced in by-product ovens xas regarded with disfavor till Dr. Otto introduced improvements which were patented in 1883 and are embodied in the Otto-Hofi'mann coke-oven, to which the Siemens regenerator is applied. In 1887 the Semet-Solvay oven for coking dry coals, or a mixture of pitchy and dry coals, came into no- tice. The Belgian ovens, designed for coking poor grades of coal, are also widely used in Europe. The retort oven used in the Semet-Solvay process is a long, narrow chamber from 30 to 33 feet long, about 6 feet high, and from 15 to the last traces of tar and ammonia are removed. The gas is now returned to be burned in the ilues of the coke-oven: l)ut as this consumes little more than half of that generated, the rest is available for other purposes. The tar is col- lected into tanks, and the ammonia is concen- trated into a strong crude liquor or into sulphate of anniionia. A ton of coal will yield from 15 to 25 pounds of sulphate and 5 to 14 gallons of tar. The demand for these by-products is rap- idly becoming greater, and in some of the most I'ccent coke-ovens their manufacture is consid- ered of more importance than the coke itself. In Germany, 12,000 Otto-Hoft'mann coke-ovens are in operation, of which 400 save the by-prod- ucts and the remainder do not. There were, in 1901, in America, either completed or in coui-se of construction, about 2000 such ovens. Of these only those in three plants attempt to save il- luminating gas. The accompanying table gives the yield in coke and other products of certain standard coals: Yields of VAEiors Coals in Otto-Hoffmann Ovens AVERAGE OPERATING RESULTS Everett. Dominion fOal Glassport. Youghiowhenv coal Germany, Westphalian coal DISTILLATION TESTS Connelsville coking coal Pittsburg ■• •• Eastern Pa. *' '* A'ir;jiiiia *' " Kanawlia ** " Coke, per cent. 72.83 75.60 74.50 7G.34 68.25 85.00 66.01 73.00 Tar, per cent. 4.99 5.0T 3.70 6.14 4.38 2.00 4.70 6.40 Sulphate, per cent. 1.010 1.100 1.280 1.223 .908 .800 1.070 1.000 Total Gas per 2000 pounds, cubic feet About 9.000 9.000 9,(i00 S.924 8,884 8,400 10,090 10,289 20 inches wide, depending on the quantity of the coal to be coked. The ovens are built in blocks of from 25 to 34, separated by flues in which gas is burned, the heat from which cokes the coal. The charge is introduced through sev- eral openings in the top, the ovens are nearly filled, and then tightly sealed. As the heat in these ovens comes from the sides instead of the top, as in the beehive oven, the flow of gases generated is from the sides to the centre, while the free expansion of the coke is somewhat checked. As a result, some eoals that in a bee- hive oven make a coke that is too soft and spongy for blast-furnace use, are hardened and strengthened in the retort oven so that they are able to bear the furnace burden. The ovens being so much narrower, the process of coking requires only half as nuich time as in the bee- hive furnace. When the charge is coked it is pushed out by means of rams through doors at each end, the doors are immediately closed, and the oven is ready for a recharge with almost no loss of heat. The coke is quenched as soon as it leaves the oven. The gases are conducted from the oven, through an opening in the top, into a collecting main. This is a hydraulic main, like that used in illuminating-gas works. The gas bubbles through the water, and a part of the tar and ammonia is condensed and separated as the gas cools, and then collected. The gas next passes through tubular condensers, where it is cooled by contact with a series of tubes through which cold water is flowing. During this process more ammonia and tar are con- densed. The gas now goes through an exhauster, and, last of all, to a scrubbing apparatus, where For a complete discussion of the coke indus- try, reference should be made to the "Mineral Resources of the United States," which form a ]iart of the Annual Kcports of the United States Geological Sui-vey : and to Piatt, "Special Re- port on Coke ^Manufacture," Pennsylvania Sec- ciid Geological Hiircei/ Report of Progress h ( Harrisburg, 1876) ; Fulton, Coke: A Treatise on the Manufacture of Coke and the Saving of By-Products (Scranton. 1895) : Parker, Manu- facture of Coke in 1S96 (Washington, 1897) ; Weeks, "Coke," in United States Census Office Eleventh Report on Manufacturing Industries (Washington, 1895). See Alimoxi.a.: Gas; and Tar. COKE, ki.ik or kok. Sir Edward (1552-1034). A distinguislied Englisli lawyer and judge. He was born at Jlilcham. in Norfolk, on February 1, 15.52. Educated at the free grammar school at Xorwich, and at Trinity College, Cambridge, he ])assed thence to ClifTord's Inn. and subsequently to the Inner Temple, to study law, and was called to the bar in April, 1578. His great ability, legal learning, and the tact he exhibited in the conduct of his cases, secured him a large prac- tice on the very threshold of his career. In 1586 he was appointed recorder of Norwich, in 1592 recorder of London, a position he resigned the same year for the Solicitor-Generalship. In the following year he was elected member of Parliament for the county of Norfolk, and wag chosen Speaker of the House of Commons. In 1594 he was made Attorney-General, and it was in this capacity that he conducted the prosecu- tion in the famous State trials of Southampton