Key points for methanol distillation control

Thread Content

1 The normal operation of methanol distillation refers to the entire system reaching equilibrium. Under the equilibrium conditions of distillation, the temperature, pressure, flow rate, and liquid level in each column remain stable. In the event of any fluctuations in operation, special attention should be paid to the lag time associated with these fluctuations on the equilibrium. Fluctuations in the load of the methanol synthesis system should be compensated for using the crude methanol tank as a buffer; the operating load of the distillation process should not be changed arbitrarily. It is necessary to maintain relative stability in the composition of crude methanol. If substandard crude methanol is added to it in an amount exceeding 20% of the total volume of crude methanol, an appropriate amount of deionized water should be added to the crude methanol tank. Substandard purified methanol should be added to the crude methanol in batches; too large a quantity at once should not be added, as this will affect the distillation process. The amount of purified methanol extracted should not exceed 3%. Since the composition of the feed varies, the components of the non-condensable gases also change; therefore, when the feed composition changes, special attention must be paid to maintaining stable tower top pressure. Reasons that disrupt distillation equilibrium: Imbalances in the distillation section can be caused by fluctuations in the heating gas, sudden changes in environmental conditions, fluctuations in the amount and composition of the raw materials, and large variations in the amount of purified methanol extracted. When the system stops due to an accident, the heating of the converted gas or steam should be turned off first; at the same time, the pumps that are in operation as well as the feed and draw-off of the tower must be stopped immediately. Further processing is carried out in accordance with the scheduled shutdown requirements.