RECOVERY OF SOOT FROM WATER BY TWO-STAGE HYDROCARBON ADDITION

1406968 Carbon; recovery from aqueous dispersions TEXACO DEVELOPMENT CORP 23 Nov 1973 [29 Dec 1972] 54560/73 Heading C1A Particulate carbon is recovered from a water dispersion by mixing the dispersion in a mixing zone with a first hydrocarbon oil having a density less than that of water in an amount just sufficient to render the carbon dry and fluffy, allowing the resulting mixture to settle in a settling zone to permit the carbon to rise to the surface of the water, adding a second hydrocarbon oil to form a hydrocarbon oil-carbon dispersion on the surface of the water, and separating the hydrocarbon oil-carbon dispersion from the water. The second hydrocarbon oil may be a petroleum residium, optionally mixed with naphtha. The first hydrocarbon oil may be a petroleum fraction boiling within the C 5 - naphtha range (optionally naphtha) and may be flashed from the hydrocarbon oil-carbon dispersion after its removal from the settling zone. The residue from the flashing process may be subjected to partial oxidation for the production of a gas composed principally of carbon monoxide and hydrogen. The C 5 -naphtha fraction from the flashing process may be recycled to the mixing zone. The amount of the first hydrocarbon oil used may be between I and 2 times the oil adsorption number of the carbon (1À5-10 lbs. of oil per lb. of carbon). The second hydrocarbon oil may be added in an amount sufficient to form a dispersion containing from 1 to 5% by weight of carbon. The watercarbon dispersion may contain between 0À5 and 4% by weight of carbon. The hydrocarbon oil-carbon dispersion may be separated at 180‹ to 475‹ F. The process may be used to recover carbon from aqueous dispersions formed in scrubbing synthesis gas with water.