GB496168A - Method and device for controlling continuously operating distilling apparatus - Google Patents

Abstract

In a continuously operating still, e.g. for oil, the distillation conditions are controlled in accordance with variations in a characteristic of one of the distillates, such characteristic being determined by a test distillation of such distillate at a temperature intermediate between its initial and final boiling points, e.g. at the 50 per cent distillation point. In a column still 1 the amount of reflux circulated by a pump 9 is regulated by a valve 11 controlled by a thermostat 10 dependent on the head temperature of the still. A part of the head product is led off continuously by a pipe 19 to a condenser 20 and receiver 21 under constant pressure provided by a line 42. Water drains out at 23 and excess condensate by the overflow pipe 22, so that there is a continuous and steady flow of condensate, as indicated by a meter 41, to the test column 12, which is heated by resistances 13, 14, 15, 16, adjustably controlled by a thermostat 18 so as to keep constant the temperature of the vapours given off by the residual liquid at <PICT:0496168/III/1> the bottom of the flask. The distillation is effected under constant pressure controlled by a regulator 26. Under these conditions one half of the head product should distil over into the receiver 25, and one half remain in the distilling flask. Such residual liquid flows out through a pipe 30 and condenser 31 through siphons 35, 36, to a calibrated exit orifice 34. Any variation in rate of accumulation of the residue raises or lowers the float 37 and actuates the flow-meter indicator 40 which in turn controls the operating point of the thermostat 10. A similar apparatus may be used at the same time to indicate continuously the final distillation temperature or the 95 per cent point.