Methanol fine-distillation technology and fine-distillation apparatus

The invention is a rectifying technique of methanol and the equipment, making several distillations on rough methanol with impurity in main tower and prepared tower to remove impurity, which gets high-purity high-quality methanol. The equipment is filling-mode construction. There are preheater and under & top condenser set on the top of the main tower, the preheater connected with the prepared tower by pipeline; there is evaporator on the top of the prepared tower, and there are oil-water separator, finished product cooler and condenser in the middle and top of the prepared tower whose evaporator is connected with the condenser and whose condenser is connected with the oil-water separator by return pipe; the evaporator of the prepared tower is connected with the main tower as well as thatof the main tower by pipeline.