Head to sump prod. ratio regulation in pre-fractionating carbo chemical phenol(s) - by calculation from properties of two feed streams of differing compsns. for phenol fraction free from cresol

摘要

Two partial inlet streams of different size and different compsn., and with periodically varied amts., are fed to a mutual pre-fractionation column. Stream (1) has a constant phenol content, and varying amts. of cresols and xylenols, and is contaminated with water and neutral oils; and stream (2) comprises phenol and o-cresol, and has a higher phenol content than (1), fluctuating greatly during relatively short periods of time. The head/sump prod. ratio is controlled without a time lag, wrt separate measurements of the two streams and measurement of a physical dimension characterising the compsn. of stream (2), the boiling temp. of this mixt. at constant pressure, and conversion of these measurements to determine and establish the amt. of sump prod. to be withdrawn, wrt the equation: a = k1b01.5 (1-k2c)+k3b20.5 (1-k2(k4+k5d+k6d2). a = amt. of sump prod. to be withdrawn, kg/h; b1, b2 = pressure differences of the measuring appts. of streams 1 and 2 (Pa); c = constant phenol concn. of stream (1), (pts. wt.); d = boiling temp. of stream (2) at constant pressure (deg. K); k1, k3 = prod. and mixing factors for amts. of stream (1) (m0.5s kg0.5/h); k2 = reciprocal deg. of distn., defined as ratio by wt. of amt. of phenol in feed mixt.; amt. of phenol in distillate (pts.wt.); and k4 to k6 = constants (-) determined once from the vapour/liq. equilibrium data of the binary phenol/o-cresol mixt. at constant pressure at the sump chamber of the column, wrt (k4+k5d+k6d2). ADVANTAGE - Xylenols and isomeric cresol fraction free from phenol may be obtd.