A kind of equipment and process for separating n-butanol-isobutanol mixture

Abstract

The present invention proposes a kind of equipment and process for separating n-butanol-isobutanol mixture, said equipment comprises: a first heat exchanger; a second heat exchanger; a low-pressure tower; a compressor; a high-pressure tower; a third heat exchanger . The equipment for separating n-butanol-isobutanol mixtures according to an embodiment of the present invention relates to a separation method of differential pressure thermally coupled rectification and autothermal recovery rectification, and specifically refers to a separation method for separating n-butanol and isobutanol mixtures Self-heat recovery and differential pressure thermal coupling integrated rectification process, this set of process and equipment can also be used for the separation of other similar near-boiling point mixtures, using this method can obtain high-purity n-butanol and iso-butanol products, and at the same time achieve the purpose of energy saving .

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a device and a process for separating n-butanol-isobutanol mixture. Background technique [0002] N-butanol is a colorless, alcohol-smelling liquid with a boiling point of 117.7°C and is slightly soluble in water. It is a solvent for various coatings and a raw material for the preparation of plasticizer dibutyl phthalate. It is also used in the manufacture of acrylic acid Butyl ester, butyl acetate, ethylene glycol butyl ether, as organic synthesis intermediates and extraction agents for biochemical drugs, are also used in the manufacture of surfactants. Isobutanol is a colorless, transparent liquid with a special smell, with a boiling point of 107°C, slightly soluble in water, easily soluble in ethanol and ether, and is a solvent for various oils, rubber, and natural resins, and can also be used for analysis Advanced solvents such as reagents, chromatographic analysis...

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Problems solved by technology

[0004] Chinese patent CN 103804140A proposes a method for separating n-butanol and isobutanol through continuous side stream rectification and salt-added extraction rectification. The first side stream (high-purity n-butanol and isobutanol mixture) is used as the feed for the extractive distillation process, and potassium salt is used as the extractant for extractive distillation, and the reflux ratio is reduced by increasing the relative volatility between the components , so as to achieve the purpose of reducing energy consumption, but it still does not get rid of the conventional rectification process of inputting heat to the bottom heat exchanger and removing heat from the top condenser. In addition, due to the introduction of extractant, an additional extractant recovery is required. Tower, which will inevitably result in an increase in equipment investment and operating costs

[0005] Chinese patent CN 201420738995 proposes a reactive distillation device for hydrogenation of butyraldehyde to produce butanol. The invention provides a reactive distillation device for production of butanol from butyraldehyde. Raw materials butyraldehyde and hydrogen pass through a reactive distillation tower, butanol The butanol product is obtained after the reaction and separation of the rectification tower, and then the butanol product is separated in the n-isobutanol separation tower, and the n-butanol product with a mass purity higher than 99.5% is obtained at the bottom of the tower, and the mass purity is higher than 99% at the top of the tower. Although high-purity n-butanol and isobutanol products are obtained in a single rectification column, the liquid phase reflux at the top of the tower is very large, and the reflux ratio is 20 to 100. A higher reflux ratio will cause The increase in operating costs and equipment costs reduces the economics of process unit operation

[0006] Literature (Industrial&Engineering Chemistry Research, 2014, 53(37):14440-14445) discloses two mechanical vapor recompression heat pump rectification processes to separate n-butanol and isobutanol mixtures. The results show that compared with conventional rectification, the column Kettle liquid flash reboiler heat pump rectification and tower top gas direct compression heat pump rectification can save energy by 67.92% and 72.92% respectively. Although the energy saving effect is remarkable, it does not consider the raw material preheating part. , the energy saving is about 50%

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