Method for continuous production of N-methyldiethanolamine

Abstract

The invention relates to a method for continuous production of N-methyldiethanolamine, which comprises the following steps: (1) pumping raw materials of epoxy ethane and monomethyl amine into a mixer through a metering pump respectively for mixing, wherein the amount-to-substance ratio of the epoxy ethane to the monomethyl amine is 1:1.2-1.5; then sending the mixed raw materials into a reactor, reacting under the pressure of 3Mpa-6Mpa and the temperature of 100 DEG C-150 DEG C within the reactor, thus obtaining a mixture containing N-methyldiethanolamine; (2) sending the mixture containing N-methyldiethanolamine into an ammonia vaporizing tower, distilling and separating the crude products of monomethyl amine and N-methyldiethanolamine; and (3) sending the N-methyldiethanolamine crude product into a light component distillation tower and a vacuum distillation tower which are connected in series, distilling and separating the N-methyldiethanolamine product continuously, and recovering the N-methyldiethanolamine product from the vacuum distillation tower, wherein efficient ripple packing is arranged in the light component distillation tower and / or the vacuum distillation tower. The invention has the characteristics of continuous and steady production process, stable product quality, low material consumption and energy consumption, lowered labor intensity for operators, and easy-industrializing popularization and application.

Description

technical field [0001] The invention relates to the technical field of petrochemical industry, in particular to a method for continuously producing N-methyldiethanolamine. Background technique [0002] N-Methyldiethanolamine (N-Methyldiethanolamine), commonly known as Methyldiethanolamine (MDEA), is an excellent solvent, pharmaceutical intermediate and efficient desulfurization and decarburization agent, and can be widely used in desulfurization, purification and emulsification of oilfield gas and coal gas Agents and acid gas absorbents, acid-base control agents and polyurethane foam catalysts, etc. [0003] In the prior art, the general production of N-methyldiethanolamine at home and abroad adopts a batch production process, such as figure 1 Shown, wherein, the process of reaction and distilling amine is continuous, but rectifying process is intermittent, owing to adopting this intermittent rectifying technology, has limited the raising of production capacity of N-methyld...

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Problems solved by technology

Because the purchased catalyst contains a large amount of water, during the reaction, part of the water and ethylene oxide generate by-product diethylene glycol, which makes the selectivity of the reaction relatively low, the yield of the product is also low, and also increases the material consumption; another On the one hand, since the boiling point difference between the by-product diethylene glycol and the product N-methyldiethanolamine is only 2°C, the two substances are difficult to separate during rectification, resulting in low purity of the product; The remaining water must be steamed out, thus further increasing energy consumption

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