Butene separation
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Question: In industrial production, after the MTBE unit, butene-1 needs to be separated from non-reformed C4 fractions – what methods are used for this purpose?
Distillation is used to separate butene-1: first, the components lighter than butene-1 are removed, and then butene-1 is separated from the heavier components.
Use a distillation tower to remove the light components first, then the heavy ones!
First, MTBE is removed, followed by the separation of alkanes and olefins; the olefins are then separated further. The process flow is optimized and selected based on the actual scale.
Qilu Petrochemical uses two towers for separation!
1.1.2.4 Principles of 1-butene purification 1-butene purification is based on the principles of conventional pressure distillation. That is, the C4 hydrocarbons after etherification undergo multiple cycles of partial condensation and partial vaporization in the light-end removal and heavy-end removal towers, to remove light components such as C3 hydrocarbons and isobutane, while water is removed through azeotropic distillation ； The by-products such as cis-2-butene, trans-2-butene, and n-butane are removed from 1-butene, resulting in polymer-grade 1-butene. 1-butene belongs to the intermediate fraction in the carbon four fractions after etherification; its boiling point differs from that of the isobutylene fraction by only 0.6°C, making it impossible to separate them using conventional distillation methods. The boiling point of 1-butene differs from that of isobutane, which is lighter than it, by only 5.5°C, while it differs from that of n-butane, which is heavier, by 5.8°C. To address this issue, this process employs a two-step precision distillation technique to remove the light components and heavy components sequentially, thereby yielding high-purity 1-butene product.