Device and method for recovering and purifying n-methylpyrrolidone
A technology of methylpyrrolidone and absorption tower, which is applied in the chemical industry and can solve the problems of increased NMP emission concentration limit, unreachable condensation method, and high cost.
Active Publication Date: 2019-12-31
岳阳市德立机械设备有限公司
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Problems solved by technology
The adsorption method is separated by the difference in polarity between the adsorbent and the medium, which has the characteristics of high absorption rate and high recovery rate, but the cost is high due to the quantitative loss of the adsorbent; the multi-stage condensation method makes the tail gas However, due to increasingly stringent environmental protection requirements, the concentration limit of NMP emissions has been increasing, and the condensation method has been unable to achieve the desired effect; the spray method generally uses water to spray and absorb the tail gas to obtain the required Emission concentration, but water consumption and it is difficult to obtain high-concentration NMP recovery liquid (generally only 50%~80%), resulting in higher purification and refining costs
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Embodiment 1
[0061] The tail gas containing N-methylpyrrolidone (8000Nm 3 / h, containing NMP400kg / h) is sent to the lower part of the absorption tower after being pressurized by the feed fan, and the purified liquid (purified water 2500kg / h, circulating absorption liquid 50kg / h, containing NMP5kg / h) is sent to the upper part of the absorption tower, continuously The rising tail gas containing N-methylpyrrolidone is in reverse contact with the purification liquid continuously flowing to the bottom, and is cooled and absorbed through a three-stage cycle to obtain up-to-standard exhaust gas (NMP concentration less than 10ppm) and absorption of N-methylpyrrolidone containing 90% concentration liquid.
[0062] The above-mentioned absorption liquid containing 90% N-methylpyrrolidone is exchanged with the gas phase product through the feed heat exchanger to 120°C, and then enters the rectification tower for rectification. The rectification tower adopts a packed tower with a top pressure of 10kPa....
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The invention provides a device and a method for recovering and purifying N-methyl pyrrolidone. At least three stages of circulating cooling devices are arranged, so that an absorption liquid containing high-concentration N-methyl pyrrolidone can be obtained, and a tail gas exhaust standard is met. A cooler of each stage of circulating cooling device can control the absorption temperature, and the absorption effect is improved. The product is directly extracted through a column reactor, so that high-purity N-methyl pyrrolidone is obtained, and waste water at the tower top is directly absorbed and utilized, thus,the yield of N-methyl pyrrolidone is increased, and the treatment cost is saved.
Description
technical field [0001] The invention relates to the technical field of the chemical industry, in particular to a device and a method for recovering and purifying N-methylpyrrolidone. Background technique [0002] The lithium battery industry is developing rapidly in the context of strong demand for clean energy. When manufacturing a lithium battery, a layer of polymer needs to be coated on the positive and negative electrodes of the battery. The polymer needs to be dissolved in an organic solvent and then coated on the surface of the electrode sheet, and then dried to make the organic solvent from the positive and negative electrodes. off the sheet. Because NMP (N-methylpyrrolidone) has many advantages such as high flash point, good thermal stability, good safety, and good solubility, it is widely used as an organic solvent in the lithium battery manufacturing industry. However, during use, the NMP will be vaporized and discharged with the dry exhaust. With the gradual in...
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IPC IPC(8): C07D207/267
CPCC07D207/267
Inventor 张德亮杨劲张佳文
Owner 岳阳市德立机械设备有限公司