September, 1928
I,VDUSTRIAL A X D ENGISEERISG CHEMISTRY
is formed as well as HZ,CH,, CZ&, CZH6, and C3Hs. Silica has but little catalytic effect a t 575" C. and no carbon is produced. At 576' C. in silica vessels the only products from the decomposition of C2H6 are C ~ H and I H?. The reaction is first order over a considerable pressure range. Other products appear only after the concentration of C2H4 from the decomposition becomes considerable. The decomposition of C3H8 under these conditions may be explained on the assumption of the following reactions.
The rates of the first two reactions are considerable and of about the same magnitude; the third reaction is much slower. The hydrogenation of C Z Ha~t 575' C. in silica vessels takes place considerably faster than the dehydrogenation. This affords some measure of confirmation to von Wartenberg's thermodynamic calculation3. The rate of hydrogenation
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of C2H4is more dependent upon the Hz concentration than on that of CZH,. The peculiar relation between the rates at different concentrations suggests a heterogeneous reaction. The hydrogenation of C2Hd at 675' C. in silica vessels is much faster than that of C,H6 under the same conditions, as would be expected from thermodynamic information. The hydrogenations are both complicated by the well-known tendency for unsaturates to polymerize. The polymerization of C2H4a t 576" C. in silica vessels results in a relatively large amount of C3H6as well as in the production of higher hydrocarbons simultaneously with some CHI and C2&. The principal products of the polymerization of C3H6under these conditions are C4Hs and higher hydrocarbons, as well as a large amount of CHI and C ~ H I . Little if any C2H2is formed from CZHIand its polymerization products under these conditions. The polymerization in the absence of Hz results in the formation of more highly unsaturated products than when HZ is present.
Zeolite Filter Plant of Ohio Valley Water Company, Bellevue, Pa.' A. H. Kneen PENFSYLVAFIA WATER
SERVICE C O
H E territory supplied by the Ohio T-alley Water Company is located about five miles west of the city of Pittsburgh, on both sides of Ohio River. The boroughs of Bellewe, Avalon, Ben Avon, Emsworth, West View, and the township of Ross, largely residential, are on the north side of the river; and the borough of LIcKee's Rocks and township of Stowe, largely industrial, are located on the south side of the river, total population sen-ed being about 60,000. The pumping station and treatment plant are on Xeville Island, and the water supply is obtained from wells located in the gravel deposits of Ohio River. The river is highly polluted with sewage from the city of Pittsburgh and acid n aste from mines and metal-working and other industrial plants. The well n-ater is clear and ample in quantity, but is hard and contains manganese and Crenothrix. The capacity of the present wells is estimated to be approximately sly million gallons daily.
T
Zeolite Softening Plant
The plant consists of four units placed side by side and connected to a 20-inch cast-iron pipe for incoming raw water carried above and in front o f the four units. A similar pipe a t the bottom remove3 the softened water and delirers it to a half-million-gallon clear well below. Each unit is supplied with valves corresponding in position and function with the inlet, outlet, wash, and sewer valves of ordinary mechanical filters, and also with a valve parallel nith the outlet which can spill to waste directly from the underdrain manifold. All of these valves and the connecting pipes are 8-inch cast iron. The brine valve and piping is 4-inch cast iron and is tapped in between the inlet valve and the tank. ,411 valves are operated with hydraulic pressure and are controlled from an operating table placed before each unit as in filter plants. Each unit is proTided with a recording and indicating flowmeter placed beside the operating table which makes Presented before the Division of Water, Sewage, and Sanitation a t the 75th Meeting of the American Chemical Society, St Louis, Mo , Apnl 16 to 19, 192s.
, WILKES-BARRE, PA,
a rate controller unnecessary as movement of water i n any direction can be regulated with the valve and meter. The units are horizontal steel tanks, 9 by 22 feet, and are constructed exactly like a rapid sand pressure filter. The underdrain system has an 8-inch manifold with 2-inch laterals, embedded in concrete, on 6-inch centers and ha\
