Energy-saving process of coal methanol

Abstract

The invention discloses an energy-saving process of coal methanol. The process scheme comprises technical processes such as coal gasification, conversion, low-temperature methanol washing, methanol synthesis and methanol rectification. A hot water circulation system is connected with a methanol rectification unit, a lithium bromide refrigerating unit and a conversion unit to form a great circle ofa hot water system, and chilled water is connected with the lithium bromide refrigerating unit and a low-temperature methanol washing unit to form a minor cycle of a chilled water system. A connection way is that high-temperature hot water enters an inlet of a hot water circulation pump from the bottom of a hot water buffering tank, enters a methanol rectification pre-tower hot water reboiler after being pressurized, enters the lithium bromide refrigerating unit after flowing out of the reboiler, enters a conversion unit hot water heater after flowing out of the lithium bromide refrigeratingunit and returns to the hot water buffering tank after being heated by the hot water heater to form a closed cycle; and chilled water generated by the lithium bromide refrigerating unit enters the low-temperature methanol washing unit, is heated after exchanging heat with a process material and flows back to the lithium bromide refrigerating unit so as to be cooled to form a closed cycle.

Description

technical field [0001] The invention relates to a coal-to-methanol energy-saving process. Background technique [0002] At present, domestic methanol production is dominated by coal gasification, and coal-to-methanol accounts for about 70% of the total methanol production capacity. The coal-to-methanol process has the characteristics of high energy consumption, large water consumption, and high carbon emission intensity. Domestic methanol production capacity continues to expand, downstream users' growth demand is slow, and the methanol industry is under heavy competition pressure. Coal-to-methanol production devices are increasingly large-scale. By expanding the production scale, the cost of methanol products is reduced, and at the same time vigorously develop new energy-saving processes, and the new energy-saving technologies are continuously integrated into the coal-to-methanol production process to improve the overall process of methanol production. Energy efficiency, r...

AI Technical Summary

Problems solved by technology

[0003] In the process of coal-to-methanol production, the temperature of the coal gasification and conversion unit system is as high as 400°C, and finally needs to be cooled to about 40°C and sent to the low-temperature methanol washing unit. This process releases a large amount of low-grade waste heat. At present, it is generally used to recover heat to produce different High-grade steam, after the by-product steam is generally around 150-170°C, it is difficult to use. Many companies use air cooling and water cooling, which fail to effectively utilize low-temperature heat in combination with the entire process.

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