# US 8,540,804 B2 · Sour gas and acid natural gas separation membrane process by pre removal of dissolved elemental sulfur for plugging prevention

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- Number: US 8,540,804 B2
- Document ID: US8540804B2
- Status: Granted
- Kind: B2
- Application number: 12/916,701
- Filed: 2010-11-01
- Published: 2012-05-03
- Granted: 2013-09-24
- Earliest claimed: 2010-11-01
- Assignees: Saudi Arabian Oil Company
- Applicants: Milind M. Vaidya; Jean-Pierre R. Ballaguet; Sebastien A. Duval; Anwar H. Khawajah
- Inventors: Milind M. Vaidya; Jean-Pierre R. Ballaguet; Sebastien A. Duval; Anwar H. Khawajah
- Web page: https://patentgrep.com/patent/US8540804B2

## CPC

- C07C 7/11: by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
- B01D 53/14: by absorption
- B01D 53/229: {Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)}
- B01D 2256/245: Methane
- B01D 2257/102: Nitrogen
- B01D 2257/30: Sulfur compounds
- B01D 2257/304: Hydrogen sulfide
- B01D 2257/504: Carbon dioxide
- B01D 2257/80: Water
- Y02C 20/40: of CO2
- 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)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

Methods for removing sulfur from a gas stream prior to sending the gas stream to a gas separation membrane system are provided. Two schemes are available. When the sulfur content is high or flow is relatively high, a scheme including two columns where one tower is regenerated if the sulfur concentration exceeds a preset value can be used. When the sulfur content is low or flow is relatively low, a scheme including one column and an absorption bed.

## Claims

### Claim 1

A method of removing sulfur from a gas stream comprising the steps of:
a. contacting the gas stream with a solvent to selectively absorb at least a portion of elemental sulfur from the gas stream such that the gas stream has a sulfur concentration that is substantially less than prior to the gas stream being contacted with the solvent;
b. filtering entrained liquid droplets from the gas stream so that sulfur does not become deposited on a gas separation membrane; and
c. passing the gas stream through the gas separation membrane.

### Claim 2 (depends on 1)

The method of claim 1, wherein the step of contacting the gas stream with a solvent occurs in a solvent scrubber.

### Claim 3 (depends on 1)

The method of claim 1, wherein the step of contacting the gas stream with a solvent occurs when the gas stream is flowing upstream and the solvent is flowing downstream counter currently to the gas stream.

### Claim 4 (depends on 1)

The method of claim 1, wherein the step of filtering entrained liquid droplets occurs in a coalescing filter.

### Claim 5 (depends on 2)

The method of claim 2, further comprising the step of regenerating the solvent by sending a gas capable of dissolving sulfur through the solvent scrubber.

### Claim 6 (depends on 5)

The method of claim 5, wherein the gas capable of dissolving sulfur comprises hydrogen sulfide recovered from the gas separation membrane or recovered from an amine unit regenerator outlet.

### Claim 7 (depends on 5)

The method of claim 5, wherein the step of regenerating the solvent scrubber occurs at a pressure operative to compensate for pressure loss in the solvent scrubber and its piping.

### Claim 8 (depends on 1)

The method of claim 1, wherein the step of contacting the gas stream with the solvent occurs at a pressure substantially similar to a feed gas pressure of the gas stream.

### Claim 9 (depends on 1)

The method of claim 1, further comprising the step of analyzing a sulfur concentration of an overhead stream of the solvent scrubber and sending the gas stream to a second column if the sulfur concentration exceeds a sulfur solubility estimated in retentate and permeate flows by membrane separation process simulation.