# US 8,541,630 B2 · Process for producing dimethyl ether from methanol

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- Number: US 8,541,630 B2
- Document ID: US8541630B2
- Status: Granted
- Kind: B2
- Application number: 12/934,313
- Filed: 2008-03-26
- Published: 2011-03-17
- Granted: 2013-09-24
- Earliest claimed: 2008-03-26
- Assignees: China Petroleum & Chemical Corporation; Research Institute of Petroleum Processing, Sinopec
- Applicants: Xiangbo Guo; Zheng Li; Qiang Li; Chaogang Xie; Keyong Yang; Anguo Mao; Xueliang Chang; Genquan Zhu
- Inventors: Xiangbo Guo; Zheng Li; Qiang Li; Chaogang Xie; Keyong Yang; Anguo Mao; Xueliang Chang; Genquan Zhu
- Web page: https://patentgrep.com/patent/US8541630B2

## CPC

- C07C 41/09: by dehydration of compounds containing hydroxy groups
- B01J 29/005: {Mixtures of molecular sieves comprising at least one molecular sieve which is not an aluminosilicate zeolite, e.g. from groups B01J29/03 - B01J29/049 or B01J29/82 - B01J29/89}
- B01J 29/084: {Y-type faujasite}
- B01J 29/80: Mixtures of different zeolites
- B01J 29/90: Regeneration or reactivation
- C07C 43/04: Saturated ethers
- B01J 29/40: of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J 29/7007: {Zeolite Beta}
- B01J 29/85: Silicoaluminophosphates [SAPO compounds]
- Y02P 20/584: Recycling of catalysts
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Disclosed is a process for producing dimethyl ether from methanol, which is characterized in that the absorbing liquid used in said absorbing column is the bottom liquid of DME-fractionating column and/or bottom waste water of the methanol-recovering column. Said process can significantly reduce energy consumption of the apparatus.

## Claims

### Claim 1

A method of producing dimethyl ether from methanol, which comprises the following steps of:
a methanol feedstock is sent to a catalyst-fluidizable reactor and contacted with the catalyst to conduct a dehydration reaction to produce a dehydrated reaction stream; and said dehydrated reaction stream is passed to a gas-solid separator to separate from the catalyst and obtain a carbon-deposited catalyst and a dehydrated reaction product,
wherein, a portion or all of said carbon-deposited catalyst is sent to a regenerator to burn the coke for regeneration in a continuous or intermittent manner; and a regenerated catalyst is sent back to the reactor and contacted with the methanol feedstock to react,
wherein, said dehydrated reaction product is sent to a separation device comprising an absorbing column and a DME rectification column, and optionally a methanol recovery column; a product stream consisting mainly of DME is obtained in the upper part of the DME rectification column; a noncondensable gas entrained with DME and/or methanol is obtained on the top of the DME rectification column; said noncondensable gas is sent to the absorbing column to absorb the entrained DME and/or methanol with an absorbing liquid; the DME rectification column bottom liquid consists substantially of unconverted methanol and water; the DME rectification column bottom liquid is optionally separated by the methanol recovery column to obtain methanol in the upper part of the methanol recovery column and waste water at the methanol recovery column bottom, and
wherein the absorbing liquid used in the absorbing column is the DME rectification column bottom liquid and/or waste water from the methanol recovery column bottom.

### Claim 2 (depends on 1)

The method of claim 1, wherein the methanol feedstock has a methanol content of 5-100 wt %.

### Claim 3 (depends on 1)

The method of claim 1, wherein the catalyst contains Y-zeolite and optionally other molecular sieve but does not contain inorganic oxide(s) and clay.

### Claim 4 (depends on 1)

The method of claim 1, wherein said catalyst contains inorganic oxide(s), clay, Y-zeolite, and optionally other molecular sieve.

### Claim 5 (depends on 3, 4)

The method of claim 3 or 4, wherein said other molecular sieve is one or more selected from meso porous zeolites, Beta-zeolites, and SAPO-molecular sieves.

### Claim 6 (depends on 3, 4)

The method of claim 3 or 4, wherein the weight ratio of other molecular sieve to Y-zeolite is 0-10.

### Claim 7 (depends on 3, 4)

The method of claim 3 or 4, wherein said Y-zeolite is selected from the group consisting of Y, HY, REY, REHY, USY, REUSY and mixtures thereof.

### Claim 8 (depends on 5)

The method of claim 5, wherein said meso porous zeolite includes ZRP series, ZSP series, ZSM series zeolites and their derivative or modified zeolites.

### Claim 9 (depends on 3, 4)

The method of claim 3 or 4, wherein said inorganic oxide is selected from the group consisting of alumina, silica, amorphous silica-alumina and mixtures thereof; and the clay is kaolin and/or halloysite.

### Claim 10 (depends on 1)

The method of claim 1, wherein the dehydration reaction is conducted at a temperature of 100-550° C., under a pressure of 1˜1000 kPa, with a weight ratio of the catalyst to the methanol feedstock of 0.001-50, at a weight hourly space velocity of 0.01-100 −.

### Claim 11 (depends on 1)

The method of claim 1, wherein the proportion of the carbon-deposited catalyst subjected to coke-burning is 0.5-100% by the total weight of the carbon-deposited catalyst.

### Claim 12 (depends on 1, 11)

The method of claim 1 or 11, wherein when a portion of the carbon-deposited catalyst enters the regenerator for the coke-burning regeneration, the remaining carbon-deposited catalyst returns to the reactor, and said portion of the carbon-deposited catalyst subjected to coke-burning comprises 0.5-99% by the total weight of the carbon-deposited catalyst.

### Claim 13 (depends on 1)

The method of claim 1, wherein the regeneration is one-stage regeneration or two-stage regeneration, and said regenerated catalyst is a partially regenerated catalyst and/or a full regenerated catalyst.

### Claim 14 (depends on 3, 4)

The method of claim 3 or 4, wherein said catalyst containing Y-zeolite is selected from the group consisting of a fresh catalyst, a regenerated catalyst, a half-regenerated catalyst, a catalyst to be regenerated, and a combination thereof.

### Claim 15 (depends on 1)

The method of claim 1, wherein the catalyst-fluidizable reactor is selected from the group consisting of a fluidized bed, a riser, a descending transfer line reactor, a composite reactor of riser and fluidized bed, a composite reactor of riser and descending transfer line, a composite reactor of two or more risers, a composite reactor of two or more fluidized beds, and a composite reactor of two or more descending transfer lines, each of the above reactors may be divided into two or more reaction zones.

### Claim 16 (depends on 1)

The method of claim 1, wherein the regenerated catalyst is cooled to 100-650° C. in a direct or indirect heat-exchange manner, and then sent back to the reactor.

### Claim 17 (depends on 16)

The method of claim 16, wherein the direct heat-exchange is to directly contact the regenerated catalyst with air or steam having a lower temperature for heat-exchange, and the direct heat-exchanger is embodied in a fluidized bed or a riser; wherein the indirect heat-exchange is to use a heat exchanger, through the shell of which the hot catalyst passes and through the tube of which the saturated water or other heat-exchanging medium passes.

### Claim 18 (depends on 1)

The method of claim 1, wherein the methanol feedstock is in a liquid phase form or in a gas phase form.

### Claim 19 (depends on 1)

The method of claim 1, wherein the methanol feedstock is indirectly heat-exchanged with the reaction stream and the catalyst in the reactor and/or the catalyst in the regenerator before being fed to the catalyst-fluidizable reactor and contacted with the catalyst.

### Claim 20 (depends on 1)

The method of claim 1, wherein the separation device comprises an absorbing column, a DME rectification column, and a methanol recovery column, wherein 99.9-90 vol % of the DME rectification column bottom liquid is sent into the methanol recovery column, and 0.1-10 vol % of the DME rectification column bottom liquid is sent into the absorbing column as the absorbing liquid.

### Claim 21 (depends on 1)

The method of claim 1, wherein the separation device further comprises a gas-liquid separator, wherein the dehydrated reaction product and/or the absorbing column bottom liquid is sent to the gas-liquid separator; after the gas-liquid separation, a liquid phase portion and a gas phase portion are obtained, wherein the liquid phase portion is sent to the DME rectification column, and the gas phase portion is sent to the absorbing column.

### Claim 22 (depends on 1)

The method of claim 1, wherein the DME rectification column is a packed column or a plate column; wherein the methanol recovery column is a packed column or a plate column; and the absorbing column is a packed column or a plate column.

### Claim 23 (depends on 22)

The method of claim 22, wherein the DME rectification column is operated under a pressure of 0.1-1.5 MPa, at a column top temperature of 20-90° C. and a column bottom temperature of 100-220° C.; wherein the DME rectification column has a theoretical plate number of 10-35, the inlet is at a position between the 4th plate and the 16th plate counted from the column top, and the outlet for DME is at a position between the 1st plate and the 5th plate counted from the column top.

### Claim 24 (depends on 22)

The method of claim 22, wherein the methanol recovery column is operated under a pressure of 0.01-0.6 MPa, at a column top temperature of 65-170° C. and a bottom column temperature of 100-220° C.; wherein the methanol recovery column has a theoretical plate number of 10-35, the inlet is at a position between the 4th plate and the 16th plate counted from the column top, and the outlet for methanol vapor is at a position between the 1st plate and the 5th plate counted from the column top.

### Claim 25 (depends on 22)

The method of claim 22, wherein the absorbing column is operated under a pressure of 0.1-1.5 MPa, at a temperature of 30-70° C., wherein the absorbing column has a theoretical plate number of 1-15, and the inlet is in the middle-lower part of the column.