FIELD: control of fractionating processes in oil refining. SUBSTANCE: fractionating plant includes reservoir for starting mixture, heat exchanger, fractionating tower, boiler, condenser, phlegma reservoir, starting material flow regulator, phlegma reservoir level regulator by distillate; pumping units are used for measurement and control of total flow rate in stripping reservoir, phlegma reservoir and fractionating tower, flow rate of distillate from phlegma reservoir, flow rate of finished product in stripping reservoirs and flow rate of stillage residue; to this end, working characteristics of pumping units pertaining to power and pressure head developed by each pump depending on flow rate and flow rate coefficients are determined through subtraction of result of division of power by pressure developed at closed gate valve at pump outlet in the beginning of the working characteristic from result of division of power acting on pump shaft on pressure developed by this pump. According to coefficient thus found, working curve is plotted and its mathematical description is found. Then, magnitude of flow rate is preset for fractionating tower as a whole and actual flow rate is measured and if these magnitude are not equal, signal is furnished to valve under control till these magnitudes become equal. Level in phlegma reservoir and rate of flow of distillate from this reservoir are measured and regulated till preset magnitudes have been obtained; flow rate of raw material fed from tower to each stripping reservoir is measured through differentiating the magnitude of dynamic level in stripping reservoir; level of liquid in each stripping reservoir is regulated through pumping finished product from it by means of pumping unit and measuring its flow rate; rate of crossflow from fractionating tower to stripping reservoir is determined. Rate of crossflow is maintained at constant level through control by means of valve found in crossflow line between stripping reservoir and fractionating tower; control is effected in succession and is continued till magnitude of crossflow becomes equal to preset value; level of stillage residue in fractionating tower is regulated and its flow rate is measured; simultaneously, material balance is maintained in fractionating tower and rate of flow of distillate in phlegm reservoir, rate of flow of finished product in stripping reservoir and flow rate of stillage residue are summed up and magnitude thus obtained is compared with amount of starting material fed to tower; these magnitudes shall be equal. EFFECT: enhanced reliability, accuracy and economical efficiency in maintaining material balance in stripping and phlegma reservoirs and in fractionating tower as a whole. 4 dwg
