CN-117753036-B - Device and method for separating mixture of chloromethane and isobutane

CN117753036BCN 117753036 BCN117753036 BCN 117753036BCN-117753036-B

Abstract

The invention provides a device and a method for separating a mixture of chloromethane and isobutane, which comprise an extraction rectifying tower, wherein a mixture feed inlet of chloromethane and isobutane, an extractant feed inlet and a chloromethane gas phase outlet are arranged on the extraction rectifying tower, an extractant conveyed by the extractant feed inlet comprises n-hexane and/or isohexane, a cooler connected with the bottom of the extraction rectifying tower, an extractant recovery tower connected with the cooler, an isobutane recovery unit connected with the top of the extractant recovery tower, an extractant recovery tower kettle reboiler connected with the bottom of the extractant recovery tower, and an extractant buffer tank connected through a pipeline. The device can separate the chloromethane and the isobutane through the specific type of extractant to obtain the chloromethane and the isobutane with high purity, and in addition, the device utilizes the energy coupling technology, so that the energy consumption is low.

Inventors

Han Deqiu
ZOU XIONG
CUI YALI
QIU HAIHUI
ZHAI YIFEI
MENG WEI
LI TING

Assignees

黄河三角洲京博化工研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20231220

Claims (9)

1. The device for separating the mixture of the chloromethane and the isobutane comprises an extraction rectifying tower, wherein a mixture feed inlet of the chloromethane and the isobutane, an extractant feed inlet and a chloromethane gas-phase outlet are arranged on the extraction rectifying tower; a cooler connected with the bottom of the extraction rectifying tower; An extractant recovery column connected to the cooler; an isobutane recovery unit connected to the top of the extractant recovery column; And the extracting agent buffer tank is connected with the tower bottom reboiler of the extracting agent recovery tower through a pipeline.
2. The apparatus of claim 1, further comprising a methyl chloride and isobutane mixture buffer tank connected to the methyl chloride and isobutane mixture feed port by a mixture feed pump.
3. The apparatus of claim 1, wherein an extractive distillation column overhead condenser, an extractive distillation column overhead condenser tank, an extractive distillation column overhead reflux pump, and a chloromethane product buffer tank are connected in sequence with the chloromethane gas phase outlet.
4. The device according to claim 1, wherein the bottom of the extractive distillation column is connected with an extractant recovery column primary feed cooler and an extractant recovery column secondary feed cooler; the extractant recovery column secondary feed cooler is connected to the extractant recovery column.
5. The apparatus according to claim 1, wherein the isobutane recovery unit comprises: The extracting agent recovery tower top condenser, the extracting agent recovery tower top condensing tank, the extracting agent recovery tower top reflux pump and the isobutane product buffer tank are sequentially connected with the extracting agent recovery tower top.
6. The apparatus of claim 1, further comprising an extractant product condenser in communication with the bottom of the extractant recovery column; The extractant product condenser is communicated with the extractant buffer tank through the extractant circulating pump.
7. A process for separating a mixture of methyl chloride and isobutane comprising the steps of: Extracting and rectifying the mixture of chloromethane and isobutane under the action of an extractant to obtain chloromethane and tower bottom liquid of an extraction rectifying tower, wherein the extractant comprises isohexane and/or n-hexane; and (3) cooling the tower bottom liquid of the extraction rectifying tower, and then recovering the extractant and collecting the isobutane.
8. The method of claim 7, wherein the pressure of extractive distillation is 600 to 850 kpa; The temperature of the extraction rectification is 80-125 ℃.
9. The method according to claim 7, wherein the number of theoretical plates of the tower is 20-40 when the extractant is recovered; the theoretical plate number of the tower is 60-80 during extraction.

Description

Device and method for separating mixture of chloromethane and isobutane Technical Field The invention belongs to the technical field of separation, and particularly relates to a device and a method for separating a mixture of chloromethane and isobutane. Background Methyl chloride is a colorless, odorless and volatile organic compound, and is used as a solvent for producing rubber, pesticides, organic silicon and other products. Isobutane is colorless combustible gas at normal temperature and pressure, is slightly soluble in water, can be dissolved in ethanol, diethyl ether and the like, and is mainly used for producing products such as isobutene, n-butane, alkylated oil and the like. The mixed system of chloromethane and isobutane is commonly used in the fields of rubber, organic solvents and pesticide synthesis, and the separation of high-purity chloromethane and isobutane is beneficial to improving the quality of products such as rubber, pesticides and alkylated oil. The analysis shows that the chloromethane and the isobutane form an azeotropic system, and no method and device for effectively separating the mixture of the chloromethane and the isobutane are found in the related documents and patents at home and abroad. Disclosure of Invention In view of the above, an object of the present invention is to provide an apparatus and a method for separating a mixture of methyl chloride and isobutane, which can separate methyl chloride from isobutane components to obtain a high-purity methyl chloride solution. The invention provides a device for separating a mixture of chloromethane and isobutane, which comprises an extraction rectifying tower, wherein a mixture feed inlet of chloromethane and isobutane, an extractant feed inlet and a chloromethane gas-phase outlet are arranged on the extraction rectifying tower; a cooler connected with the bottom of the extraction rectifying tower; An extractant recovery column connected to the cooler; an isobutane recovery unit connected to the top of the extractant recovery column; And the extracting agent buffer tank is connected with the tower bottom reboiler of the extracting agent recovery tower through a pipeline. Preferably, the method further comprises a methyl chloride and isobutane mixture buffer tank, wherein the methyl chloride and isobutane mixture buffer tank is connected to the methyl chloride and isobutane mixture feed inlet through a mixture feed pump. Preferably, the extraction rectifying tower top condenser, the extraction rectifying tower top condensing tank, the extraction rectifying tower top reflux pump and the chloromethane product buffer tank are sequentially connected with the chloromethane gas phase outlet. Preferably, the bottom of the extraction rectifying tower is connected with an extractant recovery tower primary feed cooler and an extractant recovery tower secondary feed cooler; the extractant recovery column secondary feed cooler is connected to the extractant recovery column. Preferably, the isobutane recovery unit comprises: And the extractant recovery tower top condenser, the tower top condensing tank, the extractant recovery tower top reflux pump and the isobutane product buffer tank are sequentially connected with the top of the extractant recovery tower. Preferably, the device also comprises an extractant product condenser communicated with the bottom of the extractant recovery tower; The extractant product condenser is communicated with the extractant buffer tank through the extractant circulating pump. The invention provides a method for separating a mixture of methyl chloride and isobutane, which comprises the following steps: Extracting and rectifying the mixture of chloromethane and isobutane under the action of an extracting agent to obtain chloromethane and tower bottom liquid of an extraction rectifying tower; and (3) cooling the tower bottom liquid of the extraction rectifying tower, and then recovering the extractant and collecting the isobutane. Preferably, the extractant comprises isohexane and/or n-hexane. Preferably, the pressure of the extractive distillation is 600-850 kpa; The temperature of the extraction rectification is 40-185 ℃. Preferably, the theoretical plate number of the tower is 20-40 when the extractant is recovered; the theoretical plate number of the tower is 60-80 during extraction. The invention provides a device for separating a mixture of chloromethane and isobutane, which comprises an extraction rectifying tower, wherein a mixture feed inlet of chloromethane and isobutane, an extractant feed inlet and a chloromethane gas-phase outlet are arranged on the extraction rectifying tower, an extractant conveyed by the extractant feed inlet comprises n-hexane and/or isohexane, a cooler connected with the bottom of the extraction rectifying tower, an extractant recovery tower connected with the cooler, an isobutane recovery unit connected with the top of the extractant recovery tower, an extractant recovery to