# US 9,517,978 B2 · Methanol to olefins process

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- Number: US 9,517,978 B2
- Document ID: US9517978B2
- Status: Granted
- Kind: B2
- Application number: 14/859,870
- Filed: 2015-09-21
- Published: 2016-01-14
- Granted: 2016-12-13
- Earliest claimed: 2011-03-24
- Assignees: Lummus Technology Inc.
- Applicants: Lummus Technology Inc.
- Inventors: Stephen De Haan
- Web page: https://patentgrep.com/patent/US9517978B2

## CPC

- C07C 1/20: starting from organic compounds containing only oxygen atoms as heteroatoms
- B01J 19/24: Stationary reactors without moving elements inside (B01J19/08, B01J19/26 take precedence; with stationary particles B01J8/02)
- F25J 3/0219: {Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature}
- F25J 3/0233: {separation of CnHm with 1 carbon atom or more}
- F25J 3/0238: {separation of CnHm with 2 carbon atoms or more}
- F25J 3/0242: {separation of CnHm with 3 carbon atoms or more}
- B01J 2219/00103: in a heat exchanger separate from the reactor
- B01J 2219/24: Stationary reactors without moving elements inside
- F25J 2205/50: using absorption, i.e. with selective solvents or lean oil, heavier CnHm and including generally a regeneration step for the solvent or lean oil
- F25J 2210/12: Refinery or petrochemical off-gas
- F25J 2215/04: Recovery of liquid products
- F25J 2215/62: Ethane or ethylene
- F25J 2245/02: Recycle of a stream in general, e.g. a by-pass stream
- F25J 2270/02: Internal refrigeration with liquid vaporising loop
- F25J 2290/34: Details about subcooling of liquids
- F25J 2290/62: Details of storing a fluid in a tank
- Y02P 30/20: using bio-feedstock
- Y02P 30/40: Ethylene production
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- F25J: LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE (cryogenic pumps F04B37/08; gas storage vessels, gas holders F17; filing vessels with, or discharging from vessels, compressed, liquefied or solidified gases F17C; refrigeration machines, plants, or systems F25B)}
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A process for chilling ethylene to required storage temperatures is disclosed, the process including: cooling an ethylene product from at least one of an ethylene production process and an ethylene recovery process via indirect heat exchange with a coolant at a temperature less than about −100° C. to decrease the temperature of the ethylene product; mixing a portion of the cooled ethylene product with methane to form the coolant; expanding at least one of the coolant, the methane, and the portion of the cooled ethylene to reduce a temperature of the coolant to less than −100° C. prior to the cooling; and feeding the heat exchanged coolant to at least one of the ethylene production process, the ethylene recovery process, and an open-loop refrigeration system.

## Claims

### Claim 1

A system for conversion of methanol to olefins, the system comprising:
a reactor containing a catalyst, the catalyst configured to react the methanol to form an effluent, the effluent further comprising methane, ethane, ethylene, and C3+ hydrocarbons;
a first separator configured to separate the effluent and recover a light fraction comprising the methane and a heavy fraction comprising the ethane, the ethylene, and the C3+ hydrocarbons;
a second separator configured to separate the heavy fraction to form an ethane-rich fraction, an ethylene-rich fraction, and one or more fractions comprising the C3+ hydrocarbons;
an indirect heat exchanger configured to cool the ethylene-rich fraction with a coolant to produce a cooled ethylene product having a temperature less than −100° C.; and
a mixer configured to mix a portion of the cooled ethylene-rich fraction with methane, and expand the mixture, to form the coolant;
wherein the coolant is configured to provide cooling duty to at least one of reactor, the first separator, the second separator, and the indirect heat exchanger.

### Claim 2 (depends on 1)

The system of claim 1, further comprising an atmospheric storage tank configured to store the cooled ethylene product.

### Claim 3 (depends on 2)

The system of claim 2, wherein the ethylene-rich fraction comprises at least 98% by weight ethylene.

### Claim 4 (depends on 1)

The system of claim 1, wherein the second separator further comprises:
one or more distillation units configured to fractionate the heavy into one or more of the ethylene fraction, the ethane fraction, and the C3+ hydrocarbons.

### Claim 5 (depends on 1)

The system of claim 1, further comprises:
an extractive distillation unit containing an absorbent configured to remove at least a portion of the ethylene from at least one the effluent and the heavy fraction; and
a third separator configured to separate the ethylene from the absorbent.

### Claim 6 (depends on 1)

The system of claim 1, further comprising a flow conduit configured to feed the coolant to the reactor.

### Claim 7

A process for chilling ethylene to required storage temperatures, the process comprising:
cooling an ethylene product via indirect heat exchange with a coolant to decrease the temperature of the ethylene product to a temperature of less than −100° C., the ethylene product from at least one of an ethylene production process and an ethylene recovery process;
mixing a portion of the cooled ethylene product with methane to form the coolant;
expanding at least one of the coolant, the methane, and the portion of the cooled ethylene to reduce a temperature of the coolant to less than −100° C. prior to the cooling; and
feeding the heat exchanged coolant to at least one of the ethylene production process, the ethylene recovery process, and an open-loop refrigeration system.

### Claim 8 (depends on 7)

The process of claim 7, wherein the ethylene product is at a temperature in the range from about −10° C. to about −50° C. and the cooled ethylene product is at a temperature of less than −90° C.

### Claim 9 (depends on 8)

The process of claim 8, further comprising feeding the ethylene product to an atmospheric storage tank.

### Claim 10 (depends on 7)

The process of claim 7, wherein the ethylene production process is a methanol-to-olefins process or wherein the ethylene recovery process comprises an ethylene recovery system for recovery of ethylene produced in a methanol-to-olefins process.

### Claim 11

A process for conversion of methanol to olefins, the process comprising:
contacting methanol with a catalyst in a methanol-to-olefins reactor system;
recovering an effluent from the methanol-to-olefins reactor system comprising methane, ethane, ethylene, and C3+ hydrocarbons;
separating the effluent at a temperature of greater than approximately −90° C. to recover a light fraction comprising the methane and a heavy fraction comprising the ethane, the ethylene, and the C3+ hydrocarbons;
separating the heavy fraction to form an ethane-rich fraction, an ethylene-rich fraction, and one or more fractions comprising the C3+ hydrocarbons;
cooling the ethylene-rich fraction via indirect heat exchange with a coolant, producing a cooled ethylene-rich fraction having a temperature less than about −100° C.;
mixing a portion of the cooled ethylene-rich fraction with methane to form the coolant;
expanding at least one of the coolant, the methane, and the portion of the cooled ethylene-rich fraction to reduce a temperature of the coolant to less than −100° C. prior to the cooling; and
feeding the heat exchanged coolant to at least one of the methanol-to-olefins reactor system, the separating the effluent, and an open-loop refrigeration system used in at least one of the methanol-to-olefins reactor system and the separating the effluent.

### Claim 12 (depends on 11)

The process of claim 11, wherein the ethylene-rich fraction is at a temperature in the range from about −10° C. to about −50° C. and the cooled ethylene-rich fraction is at a temperature of less than −90° C.

### Claim 13 (depends on 12)

The process of claim 12, further comprising feeding the cooled ethylene-rich fraction to an atmospheric storage tank and wherein the cooled ethylene-rich fraction comprises at least 98% by weight ethylene.

### Claim 14 (depends on 11)

The process of claim 11, further comprising contacting the heat exchanged coolant in indirect heat exchange with at least one of a refrigerant, at least one of the one or more fractions comprising the C3+ hydrocarbons, and the effluent.

### Claim 15 (depends on 11)

The process of claim 11, wherein the separating the heavy fraction comprises:
fractionating the heavy fraction in one or more distillation units to separate the ethylene from the ethane and the C3+ hydrocarbons;
recovering the ethylene-rich fraction from the one or more distillation units.

### Claim 16 (depends on 11)

The process of claim 11, wherein at least a portion of the light fraction is used as the methane portion of the coolant.

### Claim 17 (depends on 11)

The process of claim 11, wherein the separating the effluent comprises:
contacting at least one of the effluent and the heavy fraction with an absorbent in an extractive distillation unit to partition the ethylene into the adsorbent; and
separating the ethylene from the absorbent.

### Claim 18 (depends on 11)

The process of claim 11, comprising feeding the heat exchanged coolant to the methanol-to-olefins reactor system.

### Claim 19 (depends on 11)

The process of claim 11, comprising feeding the heat exchanged coolant to the separating the effluent.

### Claim 20 (depends on 11)

The process of claim 11, comprising feeding the heat exchanged coolant to the open-loop refrigeration system.