Selection of condenser for vacuum distillation
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Dear experts and seniors, I work in the field of processing techniques and am not familiar with engineering and equipment. I would like to ask you all a question; I am very grateful for your help: When 100 kilograms of alcohol is subjected to vacuum distillation, at a vacuum level of approximately 20 mmHg, or 2660 Pa, the gas at an initial temperature of 20 degrees Celsius is converted into a liquid through condensation (with the condensate temperature at -10 degrees Celsius), and this liquid then flows into a storage tank. Someone suggested connecting the vacuum tube directly to the storage tank, but I think under these conditions, a large amount of alcohol in the tank will evaporate or even cause overflow. I want to connect the vacuum directly to the condenser, but I’m not sure if that’s possible. Thank you!
It is recommended not to do this; operating it directly connected to the condenser is very difficult to control. The usual practice is for the liquid (or gas-liquid mixture) coming out of the condenser to first enter a vapor-liquid separator; the liquid that emerges from the separator goes into a storage tank, while the gas is sent to a vacuum pump. A thermometer (or pressure gauge) is installed on the vapor-liquid separator (or on the gas line leading to the vacuum pump) for automatic control or to monitor operating conditions. I’m not sure which one you mean with this 100-kilogram one. For a small unit with a feed rate of 100 KG/H, a DN200 pipe can be used directly as the vapor-liquid separator; as for the head, an oval shape is preferred (as it can withstand negative pressures). If a conical shape is to be used, it is necessary to assess whether the equipment makes this feasible.