# US 8,785,710 B2 · Paraffin purification method and apparatus

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- Number: US 8,785,710 B2
- Document ID: US8785710B2
- Status: Granted
- Kind: B2
- Application number: 13/139,422
- Filed: 2009-12-21
- Published: 2011-10-06
- Granted: 2014-07-22
- Earliest claimed: 2008-12-24
- Assignees: Sumitomo Seika Chemicals Co., Ltd.
- Applicants: Hiroaki Nago; Shinichi Tai; Junichi Kawakami; Hiroyuki Hata; Shigeru Morimoto
- Inventors: Hiroaki Nago; Shinichi Tai; Junichi Kawakami; Hiroyuki Hata; Shigeru Morimoto
- Web page: https://patentgrep.com/patent/US8785710B2

## CPC

- C10G 21/08: Inorganic compounds only
- C07C 7/005: {Processes comprising at least two steps in series}
- C07C 7/11: by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
- C10G 21/28: Recovery of used solvent
- C10G 70/00: Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00
- C10L 3/10: Working-up natural gas or synthetic natural gas
- C10G 2300/1081: Alkanes
- C10G 2300/1088: Olefins
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS

## Abstract

A method for purifying a paraffin from a source material containing a paraffin having 2 to 6 carbon atoms and an olefin having 2 to 6 carbon atoms includes a first step of bringing the source material into contact with a silver ion-containing solution (absorption liquid) at a predetermined temperature and pressure in an absorption column 1 and recovering a non-absorbed gas not absorbed by the absorption liquid while the olefin in the source material is preferentially absorbed by the absorption liquid, and a second step of desorbing and discharging a gas component from the absorption liquid having undergone the first step at a predetermined temperature and pressure in a desorption column 2. The first step and the second step are performed continuously in parallel while the absorption liquid is circulated between the first step and the second step.

## Claims

### Claim 1

A paraffin purification method for purifying a paraffin from a source material, comprising:
introducing a source material comprising no less than 90 mol % of a paraffin having 2 to 6 carbon atoms as a main component and an olefin having 2 to 6 carbon atoms as an impurity at a bottom portion of an absorption column;
contacting the source material with an absorption liquid containing a silver ion at a first temperature and a first pressure, wherein the olefin is absorbed by the absorption liquid to produce a used absorption liquid;
recovering the paraffin that is not absorbed by the absorption liquid via a gas drawing tube connected to a top of the absorption column;
introducing the used absorption liquid to a desorption column for desorbing and discharging the olefin at a second temperature and a second pressure to produce a regenerated absorption liquid; and
returning the regenerated absorption liquid to the absorption column through a return piping that is connected to the desorption column and to the gas drawing tube,
wherein the absorption and the desorption of the olefin are performed continuously in parallel while the used and regenerated absorption liquids are circulated between the absorption column and the desorption column; and
wherein the absorption liquid contains no absorption-assisting component other than the silver ion.

### Claim 2 (depends on 1)

The paraffin purification method according to claim 1,
wherein the absorption liquid is an aqueous silver nitrate solution.

### Claim 3 (depends on 1)

The paraffin purification method according to claim 1,
wherein the second pressure is set lower than the first pressure.

### Claim 4 (depends on 1)

The paraffin purification method according to claim 1,
wherein the second temperature is set higher than the first temperature.

### Claim 5 (depends on 1)

The paraffin purification method according to claim 1,
wherein the source material and the absorption liquid are contacted counter-currently.

### Claim 6 (depends on 1)

The paraffin purification method according to claim 1,
wherein the paraffin is at least one selected from the group consisting of ethane, propane, cyclopropane, n-butane, isobutane, cyclobutane, methylcyclopropane, n-pentane, isopentane, neopentane, cyclopentane, methylcyclobutane, dimethylcyclopropane, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, cyclohexane, methylcyclopentane, 1,2-dimethylcyclobutane and trimethylcyclopropane.

### Claim 7 (depends on 1)

The paraffin purification method according to claim 1,
wherein the olefin is at least one selected from the group consisting of ethylene, propylene, cyclopropene, 1-butene, 2-butene, isobutene, cyclobutene, 1-methylcyclopropene, 2-methylcyclopropene, methylidenecyclopropane, isobutylene, 1,3-butadiene, 1,2-butadiene, cyclopentene, 2-methyl-1-butene, 1-pentene, 2-pentene, 2-methyl-2-butene, 1,4-pentadiene, 1,3-pentadiene, cyclopentene, methylenecyclobutane, vinylcyclopropane, 3-methyl-1,2-butadiene, 1,2-pentadiene, isoprene, 2,3-pentadiene, 1-hexene, 2-hexene, 3-hexene, 3,3-dimethyl-1-butene, 2,3-dimethyl-1-butene, 2,3-dimethyl-2-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-methyl-2-pentene, 3-methyl-2-pentene, 4-methyl-2-pentene, 2-ethyl-1-butene, 1,5-hexadiene, 1,4-hexadiene, 2,4-hexadiene, 2-methyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, cyclohexene, 1,3-hexadiene, 2,4-hexadiene, 1-methyl-1-cyclopentene, 3-methyl-1,3-pentadiene, 3-methyl-1,4-pentadiene and methylenecyclopentane.

### Claim 8 (depends on 1)

The paraffin purification method according to claim 1, wherein the source material contains 98-99.5 mol % of propane and 0.5-2.0 mol % of propylene.