Thermally coupled multi-effect distillation method and device for methanol

Abstract

The invention relates to the technical field of distillation in chemical separation engineering of methanol, in particular to a thermally coupled multi-effect distillation method and device for methanol. The device structurally comprises a pre-distillation column and a first distillation column which are connected in series, wherein a booster pump is arranged between the pre-distillation column and the first distillation column; a second distillation column, a third distillation column and a fourth distillation column are connected in series sequentially behind the first distillation column; apre-distillation column condenser is arranged at the top of the pre-distillation column, a pre-distillation column coupled reboiler is arranged at the bottom of the pre-distillation column, a first distillation column coupled reboiler is arranged at the bottom of the first distillation column, a second distillation column coupled reboiler is arranged at the bottom of the second distillation column, a third distillation column coupled reboiler is arranged at the bottom of the third distillation column, a fourth distillation column coupled reboiler is arranged at the bottom of the fourth distillation column, and a fourth distillation column condenser is arranged at the top of the fourth distillation column; heat is input into the columns under lower operation pressure by top steam of the columns under higher operation pressure through the corresponding coupled reboilers. The thermally coupled multi-effect distillation method and device for methanol can reduce energy consumption and reduce emission of three wastes.

Description

technical field [0001] The invention relates to the technical field of rectification in methanol chemical separation engineering, in particular to a methanol thermally coupled multi-effect rectification method and device. Background technique [0002] Methanol is one of the most important organic chemical products and organic chemical raw materials in carbon-one chemistry. Methanol rectification technology is the only method for methanol production in industry, and its energy consumption accounts for about 30% of the total energy consumption of methanol production. Advanced, energy-saving and reliable methanol rectification technology is very important for the methanol industry. It is very critical for energy saving, consumption reduction, quality improvement and emission reduction, and clean environment. The earliest industry used single-effect two rectification towers to refine methanol to obtain refined methanol. Later, with the large-scale methanol rectification device...

AI Technical Summary

Problems solved by technology

[0003] At present, industrial devices generally use common control loops and methods such as cascade and feedback to realize the control of methanol rectification system, which is simple and cheap, but cannot meet the growing production needs

The disadvantage is that too much manual intervention is required, resulting in system fluctuations, resulting in unstable product quality and high energy consumption of the device

[0004] "Analysis of Methanol Distillation Technology" (National Methanol Synthesis Technology Exchange Seminar, 2010) discusses in detail the characteristics and energy consumption of the widely used double-effect triple distillation column technology; "Improving Methanol Distillation Process Technology" ("Acetaldehyde Acetic Acid Chemical Industry", 2015 (2): 50-50) also tried to improve the methanol rectification technology; Tianjin University (Chinese patent 200710150233. The distillation column adopts heat pump distillation technology to obtain refined methanol products, but due to the particularity of the crude methanol system, the compression ratio of the heat pump is too large, which is not economically cost-effective, so it has not been applied in industry

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