Tianjin University

Zhongfeng Geng

Minhua Zhang

Yingzhe Yu

Hao Gong

He Dong

Xiuqin Dong

Shenghua Qian

Minli Tao

Yonghui Li

Cheng Liu

Huisheng Lv

The present disclosure relates to a process and a device for producing vinyl acetate by an ethylene process. By additionally arranging an ethylene recovery membrane assembly in a vinyl acetate synthesis section, the content of inert components such as nitrogen in a circulating system is controlled, ethylene gas is recovered from non-condensable gas, and a recovery rate of the ethylene reaches 58% or above. By adding sideline extraction at a refined VAC tower in a vinyl acetate refining section, a vinyl acetate product with purity higher than 99.98% is obtained, a mass fraction of acetic acid is less than or equal to 20 ppm, a mass fraction of acetaldehyde is less than or equal to 20 ppm, and a mass fraction of water is less than or equal to 100 ppm. In synthesis and refining processes of the vinyl acetate, a cooling method is adopted.

Preparation method of vinyl acetate by ethylene process and device thereof

The present disclosure relates to a method for producing vinyl acetate, comprising a vinyl acetate synthesis process, a vinyl acetate refining process and a separation process of vinyl acetate and ethyl acetate, including an acetic acid evaporator, an oxygen mixer, a vinyl acetate synthesis reactor, a first gas separating tower, a second gas separating tower, a recovered gas compressor, a water washing tower, an absorption tower and a desorption tower, a recycling gas compressor; the vinyl acetate refining process comprising an acetic acid tower, a crude VAC tower, and a fine VAC tower, a rectifying tower, an ethyl acetate tower, a water phase receiving tank, an extracting and rectifying tower and an ethyl acetate phase separator.

Method for producing vinyl acetate

The present invention discloses a method and a device for recovering ethylene during the process for producing vinyl acetate, wherein a double solvent absorption method composed of an absorbent solution and deionized water is adopted. The method is as follows: introducing an outlet stream as an absorbent solution from the upper section of the feeding plate in an acetic acid tower during the rectification stage of vinyl acetate production; delivering same to the top of the lower section of the ethylene recovery tower by a delivery pump; charging refined gas from the tower bottom of the ethylene recovery tower for contacting with the absorbent solution in a counter-current; delivering the absorption bottom solution to the rectification stage for treatment; the gas continuing to rise to the upper section of the ethylene recovery tower and contacting with the deionized water introduced from the top of the tower in a counter-current; absorbing and removing the acetic acid therein; and discharging the residual inert gas, such as N2, from the top of the ethylene recovery tower. The absorbent solution is a mixture of acetic acid, vinyl acetate and water, and comprises by weight percentage of 50-85% acetic acid, 5-30% vinyl acetate and 5-20% water.

Method for recovering ethylene during the process for producing VAC and a device thereof

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Tianjin, China

Zhongfeng Geng