Method for recovering n-butane from tail gas of maleic anhydride preparation by butane method

Abstract

The invention discloses a method for recovering n-butane from tail gas of maleic anhydride preparation by a butane method. The method comprises the following steps: (1) pressurizing the tail gas of maleic anhydride preparation by the butane method, and feeding the tail gas into a spray washer for washing and spraying; (2) sending the washed and sprayed butane-process maleic anhydride tail gas intoan adsorber, and selectively adsorbing the tail gas with an adsorbent to obtain an adsorbent for adsorbing n-butane; (3) feeding the adsorbent for adsorbing n-butane into a regenerator to react withwater vapor for regeneration to obtain n-butane-rich gas and a regenerated adsorbent; (4) sending the n-butane-rich gas into a condensation tank, and carrying out cooling and separating to obtain n-butane and water; and (5) recycling the regenerated adsorbent. According to the method, the adsorbent is used for selectively adsorbing the butane-process maleic anhydride tail gas, impurity gas is effectively removed, n-butane is obtained through regeneration and cooling separation, continuous and efficient recovery of n-butane in the tail gas of maleic anhydride preparation through the butane method is achieved, the recovery rate and quality of n-butane are improved, and meanwhile, the utilization rate of n-butane in the tail gas of maleic anhydride preparation through the butane method is increased.

Description

technical field [0001] The invention belongs to the technical field of tail gas recovery, in particular to a method for recovering n-butane in the tail gas of maleic anhydride produced by a butane process. Background technique [0002] Maleic anhydride, referred to as maleic anhydride, is widely used and its demand is increasing year by year. The domestic industrial production of maleic anhydride has gradually changed from the heavily polluting benzene oxidation method to the n-butane oxidation method. [0003] Maleic anhydride produced by butane method is to mix n-butane with air and then enter the reactor to react to generate maleic anhydride, water, CO and CO 2 reaction process. In the normal production process, the conversion rate of n-butane is only 82%, and 18% of n-butane fails to react and remains in the tail gas. How to improve the yield and utilization of n-butane is the research focus of scholars. If the n-butane in the tail gas is recycled, the production of ...

AI Technical Summary

Problems solved by technology

This method can recover n-butane in the tail gas, but n-butane and nitrogen in the recovered gas are not separated, and additional control equipment is required to ensure the composition of the raw material gas for maleic anhydride production in order to realize the production of maleic anhydride. The process is complicated and the operation is difficult.

[0009] Scientific research workers have done a large amount of related work, but as mentioned above, the existing butane legal system maleic anhydride tail gas treatment technology also has the following deficiencies: (1) the n-butane in the maleic anhydride tail gas does not reclaim or partially reclaim; 2) while recovering n-butane, there are other gases that cannot be completely separated, and these inseparable gases are circulated and introduced into the raw materials for maleic anhydride production, which will change the original process conditions for maleic anhydride production, and will have a negative impact on the maleic anhydride production system; ( 3) Increase precision gas component analysis and control equipment, making the process complex, increasing operational difficulty and equipment investment

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