# US 8,465,705 B2 · Process for the reduction/removal of the concentration of hydrogen sulfide contained in natural gas

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- Number: US 8,465,705 B2
- Document ID: US8465705B2
- Status: Granted
- Kind: B2
- Application number: 11/629,513
- Filed: 2005-06-15
- Published: 2008-02-07
- Granted: 2013-06-18
- Earliest claimed: 2004-06-25
- Assignees: ENI S.p.A.
- Applicants: Liberato Giampaolo Ciccarelli; Gian Paolo Borghi
- Inventors: Liberato Giampaolo Ciccarelli; Gian Paolo Borghi
- Web page: https://patentgrep.com/patent/US8465705B2

## CPC

- B01D 53/52: Hydrogen sulfide
- B01D 53/1468: {Removing hydrogen sulfide}
- 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)

## Abstract

Process for the removal/reduction of the hydrogen sulfide contained in natural gas which comprises: a) feeding natural gas and water to a reaction vessel maintained under thermodynamic conditions favorable for the formation of H2S hydrates and substantially at the production pressure of natural gas; b) discharging the H2S hydrates, from the bottom of the reaction vessel; c) optionally melting the hydrates and re-injecting water and/or gas comprising hydrogen sulfide and/or the hydrates as such into the same production field or into a geologically equivalent structure; and d) optionally feeding the remaining natural gas to a conventional softening process.

## Claims

### Claim 1

A process for removing hydrogen sulfide from natural gas, comprising:
feeding pressurized natural gas to a reaction vessel;
treating the natural gas at a temperature of from 15 to 25° C. at a pressure of from 5 to 15 MPa to form a solid H2S hydrate, wherein the natural gas comprises water in an amount of 40-80% by weight based on the total weight of the natural gas;
separating the solid H2S hydrates from the reaction vessel; and
at least one of (i) injecting the H2S hydrates into a geologic formation and (ii) liquefying the solid H2S hydrates,
wherein the natural gas remains gaseous during the feeding, treating and separating.

### Claim 2 (depends on 1)

The process according to claim 1, which comprises liquefying the solid H2S hydrates to form a mixture comprising gaseous H2S and an aqueous composition comprising H2S.

### Claim 3 (depends on 1)

The process according to claim 1, wherein the solid H2S hydrates are separated from the natural gas at the bottom of the reaction vessel.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the natural gas is treated by expansion in a turbine.

### Claim 5 (depends on 1)

The process according to claim 1, wherein the natural gas consists essentially of methane, hydrogen sulfide and water.

### Claim 6 (depends on 1)

The process according to claim 1, consisting of the feeding, treating and separating.

### Claim 7

A process for the removal of hydrogen sulfide from natural gas, comprising:
feeding a natural gas stream and a water stream to a reaction vessel to form a gaseous composition consisting of the natural gas and the water in the reaction vessel;
treating the gaseous composition inside the reaction vessel at a temperature of from 15 to 25° C. at a pressure of from 5 to 15 MPa to form a solid H2S hydrate, wherein the gaseous composition comprises water in an amount of 40-80% by weight based on the total weight of the composition;
separating the solid H2S hydrates from the reaction vessel; and
at least one of (i) injecting the H2S hydrates into a geologic formation and (ii) liquefying the solid H2S hydrates,
wherein the natural gas remains gaseous during the feeding and the treating.

### Claim 8 (depends on 7)

The process according to claim 7, wherein the natural gas is treated by expansion in a turbine.

### Claim 9 (depends on 7)

The process according to claim 7, wherein the natural gas consists essentially of methane, hydrogen sulfide and water.

### Claim 10 (depends on 7)

The process of claim 7, consisting of the feeding, treating and separating.