# US 10,246,394 B2 · Separation processing method for a product stream of a dimethyl ether reactor

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- Number: US 10,246,394 B2
- Document ID: US10246394B2
- Status: Granted
- Kind: B2
- Application number: 15/109,951
- Filed: 2015-01-05
- Published: 2016-11-17
- Granted: 2019-04-02
- Earliest claimed: 2014-01-07
- Assignees: Linde Aktiengesellschaft
- Applicants: Linde Aktiengesellschaft
- Inventors: Helmut Fritz; Andreas Peschel
- Web page: https://patentgrep.com/patent/US10246394B2

## CPC

- C07C 41/42: by distillation
- B01D 3/143: {by two or more of a fractionation, separation or rectification step}
- B01D 53/1493: {Selection of liquid materials for use as absorbents}
- C07C 41/40: by change of physical state, e.g. by crystallisation
- B01D 2257/108: Hydrogen
- B01D 2257/502: Carbon monoxide
- B01D 2257/504: Carbon dioxide
- B01D 2257/80: Water
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02C 20/40: of CO2
- Y02P 20/151: Reduction of greenhouse gas [GHG] emissions, e.g. CO2
- Y02P 70/10: Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method for the processing, by separation technology, of a product stream (g), containing at least dimethyl ether, methanol, water, carbon dioxide, carbon monoxide and hydrogen, from a reactor (4) used for the synthesis of dimethyl ether (z) from synthesis gas (e), is proposed. The product stream (g) is fed, in at least partially gaseous form, into an absorption column (6) operated with a liquid reflux, a gaseous top stream (m) being removed from the absorption column (6) at the top and a liquid sump stream (p) being removed at the bottom. The sump stream (p) is at least partially fed into a first distillation column (5), a gaseous transfer stream (q) containing dimethyl ether and a stream (r) predominantly containing methanol and/or water being removed from the first distillation column (5). The top stream (m) is at least partially cooled initially to a first temperature level and subsequently further cooled to one or more further temperature levels, a first condensate stream (n) being formed after the cooling to the first temperature level and one or more further condensate streams (s, t) being formed after the further cooling to the further temperature level or levels. The first condensate stream (n) is partially used to form the liquid reflux and the further condensate stream or streams (s, t) is or are at least partially fed into a further distillation column (9), from which a liquid stream (z) predominantly containing dimethyl ether and poor in or free from carbon dioxide is removed at the bottom. The invention also relates to a corresponding separation apparatus and an apparatus (100) for producing dimethyl ether.

## Claims

### Claim 1

Method for the processing, by separation technology, of a product stream (g) containing at least dimethyl ether, methanol, water, carbon dioxide, carbon monoxide and hydrogen, from a reactor (4) used for the synthesis of dimethyl ether from synthesis gas (e), comprising
feeding the product stream (g), in at least partially gaseous form, into an absorption column (6) operated with a liquid reflux, removing a gaseous top stream (m) from the absorption column (6) at the top and removing a liquid sump stream (p) at the bottom,
feeding the sump stream (p) at least partially into a first distillation column (5), withdrawing a transfer stream (q) containing dimethyl ether and a stream (r) predominantly containing methanol and/or water from the first distillation column (5),
cooling the top stream (m) at least partially initially to a first temperature level and subsequently further cooling to one or more further temperature levels, forming a first condensate stream (n) after the cooling to the first temperature level and forming one or more further condensate streams (s, t) after the further cooling to the further temperature level or levels, and
using the first condensate stream (n) partially to form the liquid reflux and feeding the further condensate stream or streams (s, t) at least partially into a further distillation column (9), from which removing a liquid stream (z) predominantly containing dimethyl ether and poor in or free from carbon dioxide at the bottom.

### Claim 2 (depends on 1)

Method according to claim 1, further comprising feeding a fraction of the first condensate stream (n) which is not used to form the liquid reflux at least partially into the first distillation column (5) or the further distillation column (9).

### Claim 3 (depends on 1)

Method according to claim 1, further comprising operating the absorption column (6) such that the top stream (m) is poor in methanol and/or water.

### Claim 4 (depends on 1)

Method according to claim 1, further comprising selecting the further temperature level or levels such that the further condensate stream or streams (s, t) is or are poor in carbon monoxide and hydrogen.

### Claim 5 (depends on 1)

Method according to claim 1, further comprising removing a gaseous top stream which is rich in carbon dioxide and poor in dimethyl ether from the further distillation column (9) at the top.

### Claim 6 (depends on 1)

Method according to claim 1, further comprising feeding the product stream (g) into the absorption column (6) at a pressure level of 20 to 100 bar.

### Claim 7 (depends on 1)

Method according to claim 1, further comprising feeding the product stream (g) into the absorption column (6) at a temperature level of 60 to 150° C.

### Claim 8 (depends on 1)

Method according to claim 1, wherein the further cooling of the top stream (m) to the further temperature level or levels comprises cooling to a minimum temperature level between the melting temperature of carbon dioxide and −15° C.

### Claim 9 (depends on 8)

Method according to claim 8, further comprising feeding a fraction of the top stream (m) which has remained in gaseous form after cooling to the minimum temperature level into a further absorption column (16).

### Claim 10 (depends on 9)

Method according to claim 9, further comprising operating the further absorption column (16) with a further liquid reflux (v) which is formed from a liquefied, carbon dioxide-rich top stream from the further distillation column (9).

### Claim 11 (depends on 1)

Method according to claim 1, wherein the product stream (g) contains 2 to 50 mol % dimethyl ether, 0.1 to 20 mol % methanol, 0.1 to 20 mol % water, 1 to 50 mol % carbon dioxide, 0.1 to 25 mol % carbon monoxide and 5 to 90 mol % hydrogen.