btu h ft 2 there is not direct flame contact with the heater tubes the product vapor separated from the bottoms liquid in the still 5 is returned to the product separator 4 fig1 a via the line 49 the heat exchanger 3 and the line 50 thus partially condensed dea the product from the heat exchanger 3 is fed to the separator 4 the liquid which is the purified product is separated from the vapor which is essentially all water vapor the separated liquid is discharged through a line 123 and pump 124 to a line 125 and through a one way valve 126 a control valve 127 a line 128 and a valve 129 for further treatment in the solvent cooler 8 fig1 c as described hereinafter in greater detail the line 50 is also connected to the line 125 through a restricted orifice 131 which passes minimum flow for pump 21 through the line 125 start up condensate flows through the valves 126 and 127 a valve 132 and a line 133 to product water storage not shown a line 135 containing a safety relief valve 136 connects the line 125 to the drain header 23 the line 125 is also connected through a valve 137 downstream of the valve 132 and the line 133 to the drain header 23.