Method for separating butane and butene by using multiple mixed solvent

Abstract

The invention relates to a method for spearing butane from butylene with the multicomponent compound of ionic liquid, saline, ethyl methyl ketone and N-formylmorpholine. The content of ionic liquid in the multicomponent compound is 1.0 to 95 percent; the content of the saline in the multicomponent compound is 0.5 to 20 percent; the electropositive ion of the ionic liquid is iminazole electropositive ion, alkyl imidazole electropositive ion or alkyl quaternary ammonium ion, or the compound thereof; the electronegative ion is tetrafluoroborate electronegative ion, hexafluorophosphoric acid electronegative ion, nitrate ion, tetrachloro aluminic acid iron, heptachlor bi aluminic acid iron, chloride ion, bromine electronegative ion or the mixture; and the ionic liquid can be dimethylformamide potassium thiocyanate compound salt, dimethylformamide sodium sulfocyanate compound salt, or the compound; the saline is potassium thiocyanate, sodium sulfocyanate, ammonium thiocyanate, sodium nitrate, potassium nitrate, sodium iodide, potassium iodide, zinc chloride, copper chloride, zinc chloride, potassium bromide, or the compound thereof.

Description

technical field [0001] The invention relates to a method for extracting and rectifying separation of butane and butene with a multi-component mixed solvent containing ionic liquid, salts, methyl ethyl ketone and N-formylmorpholine. Background technique [0002] The boiling points of butane and butene are close, and the relative volatility is close to 1. It is difficult to separate by ordinary rectification. Therefore, extractive distillation is often used for separation, that is, a polar component, that is, a solvent component, is added to the upper part of the rectification tower to make The relative volatility of butane and butene in the tower increases, improving the separation efficiency. There are many polar solvents that can be used for extraction and distillation to separate butane and butene, such as nitrogen-formyl morpholine, morpholine, mixture of nitrogen-formyl morpholine and morpholine, sulfolane, nitrogen-methylpyrrolidone, methyl ethyl ketone and A mixture o...

AI Technical Summary

Problems solved by technology

The patent "Ionic liquid as a selective additive for separating near-boiling point or azeotropic mixtures" (ZL0286951.X) provides a method for separating near-boiling point or azeotropic mixtures by extraction and rectification using ionic liquids. The invention patent directly adopts The ionic liquid is a solvent separation close to the boiling point or an azeotropic mixture. The amount of the ionic liquid added is 5-90% of the liquid phase, but the method provided by the invention patent has a big problem when it is applied to the separation of carbon four, such as: extractive distillation Tower operation is unstable, separation efficiency is low, etc., the reason is that the compatibility of ionic liquid and C4 is low, the solubility of C4 in ionic liquid is low, and the liquid itself in the extractive distillation tower is divided into two phases, that is, extraction There are three phases in the distillation column: ionic liquid phase, carbon four-phase, and vapor phase, which makes the operation of the column unstable, and the mass transfer efficiency between the vapor and liquid phases is low, resulting in low tray efficiency and low separation capacity

Images