Rectifying tech. and equipment of high purity methanol

Abstract

A rectifying apparatus for preparing high-purity (99.85%) methanol is composed of pre-rectifying tower, pressurizing tower, ordinary-pressure tower, condenser of reflux tank, re-boiler, reflux pump, pre-heater, and cooler. Its process is also disclosed. It features less consumption of energy and cooling water.

Description

technical field [0001] The invention relates to high-purity methanol rectification equipment and a process, belonging to the technical field of chemical product purification. Background technique [0002] The three-tower rectification process is currently a commonly used process for methanol rectification, such as figure 1 As shown, the use of the condensation heat of methanol vapor at the top of the pressurized column as the heat source of the condensation reboiler of the atmospheric column forms a "double-effect rectification". Compared with the double-column process, it not only saves steam, but also saves cooling water to a certain extent. However, it can be seen through analysis that there are still many links to be improved in this process: 1. The condensation heat provided by the methanol vapor at the top of the pressurized column is greater than the heat required by the reboiler of the atmospheric column, and in order to achieve a certai...

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Problems solved by technology

However, it can be seen through analysis that there are still many links to be improved in this process: 1. The condensation heat provided by the methanol vapor at the top of the pressurized column is greater than the heat required by the reboiler of the atmospheric column, and in order to achieve a certain product quality, the reflux must be increased ratio, which not only increases the load of the atmospheric column, but also causes a waste of heat energy and equipment; 2. The methanol gas-liquid mixture that comes out of the atmospheric column reboiler is generally close to the bubble point temperature, and passes through the pressurized column reflux pump Cavitation is prone to occur when it is serious, and the reflux pump cannot operate normally; 3. Liquid wax is often produced during the operation of the methanol rectification system. The alcohol content of the liquid in the stripping section of the atmospheric column is very low and the temperature is not high. Wax is very easy to precipitate, and is pumped into the reboiler after excessive accumulation in the tower kettle, and the product is strongly evaporated by heat to affect the purity of the product; 4. The rectification equipment is bulky, expensive, and consumes a lot of energy and water

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