Treatment of gases

Patent metadata

Field	Value
Publication number	US-9878910-B2
Application number	US-201414909150-A
Country	US
Kind code	B2
Filing date	Aug 14, 2014
Priority date	Aug 13, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A process and apparatus for recovering sulphur from a hydrogen sulphide containing gas stream are disclosed. A gas stream containing hydrogen sulphide gas is passed into an apparatus having a first thermal-reaction-region and a first catalytic region and reacting a portion of the hydrogen sulphide gas to sulphur dioxide and water and reacting a further portion to form sulphur vapor and water vapor to form a resultant-gas-mixture of water vapor, sulphur vapor, sulphur dioxide and hydrogen sulphide and passing a portion to the first catalytic-region whereby at least a portion of the hydrogen sulphide is reacted in the presence of a catalyst to form further sulphur vapor and water vapor and condensing at least a portion of sulphur vapor to form liquid sulphur and passing at least a portion of the liquid sulphur to a sulphur pit.

First claim

The invention claimed is:

1. A process for recovering sulphur from a hydrogen sulphide containing gas stream, the process comprising: (i) providing a gas stream comprising hydrogen sulphide gas; (ii) passing, the gas stream into an apparatus comprising a first thermal-reaction-region and a first catalytic region comprising an oxygen scavenger material comprising iron; and (1) reacting a portion of the hydrogen sulphide gas in the first thermal-reaction-region to form sulphur dioxide and water vapour and reacting a further portion of the hydrogen sulphide to form sulphur vapour and water vapour, to form a resultant-gas-mixture comprising water vapour, sulphur vapour, sulphur dioxide, and hydrogen sulphide; and (2) passing at least a portion of the resultant-gas-mixture to the first catalytic-region, whereby at least a portion of the hydrogen sulphide is reacted, in the presence of a catalyst selected from the group consisting of an oxygen tolerant catalyst selected from the group consisting of TiO 2 and Al 2 O 3 , to form further sulphur vapour and water vapour; and after step (1), step (2), or both step (1) and step (2) condensing at least a portion of said sulphur vapour to form liquid sulphur and passing at least a portion of the liquid sulphur to a sulphur pit; wherein an off-gas formed or contained in the sulphur pit by degassing the liquid sulphur in the sulphur pit at a pressure of from 0.5 to 1 MPa and further comprising combining the off-gas with a gas stream comprising O 2 before the off-gas is recycled from the sulphur pit into the process downstream of the first thermal-reaction-region and at least a portion of the off-gas is recycled from the sulphur pit to the first catalytic region or zone or more further thermal-reaction-regions downstream of the first thermal-reaction-region and further comprising recycling at least a portion of the off-gas to a second thermal-reaction-region downstream of the first thermal-reaction-region; wherein the first thermal-reaction-region is housed in a first single unit together with a first waste heat boiler and wherein the second thermal-reaction-region is housed in a second single unit together with a second waste heat boiler, wherein the gas stream of step (i) is passed through the first thermal-reaction-region, through the first waste heat boiler to the second thermal-reaction-region where it is combined with at least a portion of the recycled off-gas then said combined stream is passed through the second waste heat boiler, or wherein the first and second thermal-reaction-regions are housed in a single unit together with a multi-pass waste heat boiler; wherein the gas stream of step (1) is passed through the first thermal-reaction-region, through the multi-pass waste heat boiler to the second thermal-reaction-region where it is combined with at least a portion of the recycled off-gas, then said combined stream is passed through the multi-pass waste heat boiler.

2. The process according to claim 1 wherein the off-gas comprises at least 0.001% by volume of hydrogen sulphide based on the total volume of the off-gas.

3. The process according to claim 1 wherein the off-gas comprises less than 1% by volume of sulphur dioxide based on the total volume of the off-gas.

4. The process according to claim 1 wherein at least a portion of the off-gas is recycled from the sulphur pit to one or more further catalytic-regions downstream of the first catalytic-region.

5. The process according to claim 1 wherein the off-gas from the sulphur pit is not recycled to the first thermal-reaction-region.

6. The process according to claim 1 comprising introducing sweep gas into the sulphur pit to form off gas.

7. An apparatus for recovering sulphur from a hydrogen-sulphide-containing gas, the apparatus comprising: a first thermal-reaction-region having an inlet for a gas stream comprising hydrogen sulphide gas, means to react hydrogen sulphide in said gas stream to produce first reaction gases, and an outlet for the first reaction gases, a first catalytic-region having an inlet for the first reaction gases in fluid communication with the outlet of the first thermal-reaction-region, a sulphur pit for retaining liquid sulphur, and means for recycling gases from the sulphur pit into the apparatus downstream of the first thermal-reaction-region, wherein the apparatus includes at least one sulphur condenser and means for recycling oases from the sulphur pit to the first catalytic region and further comprises one or more further thermal-reaction-regions downstream of the first thermal-reaction-region, and means for recycling gases from the sulphur pit to the one or more further thermal-reaction-regions downstream of the first thermal-reaction-region.

8. The apparatus according to claim 7 wherein the apparatus comprises one or more further catalytic regions downstream of the first catalytic region.

9. The apparatus according to claim 7 further comprising: a catalyst for reacting hydrogen sulphide to form second reaction gases comprising sulphur vapour and water vapour, and an outlet for the second reaction gases.

10. The apparatus according to claim 7 further comprising: a first sulphur condenser arranged to receive the first reaction gases passing from the outlet of the first thermal-reaction-region to the inlet of the first catalytic region and to form liquid sulphur.

11. The apparatus according to claim 7 further comprising: a second sulphur condenser arranged to receive the second reaction gases passing from the outlet of the first catalytic-region and to form liquid sulphur.

12. The apparatus according to claim 7 further comprising: a first sulphur condenser arranged to receive the first reaction gases passing from the outlet of the first thermal-reaction-region to the inlet of the first catalytic-region and to form liquid sulphur, a second sulphur condenser arranged to receive the second reaction gases passing from the outlet of the first catalytic-region and to form liquid sulphur, and means for transferring at least a portion of the liquid sulphur from the first sulphur condenser, the second sulphur condenser or both the first and second sulphur condenser to the sulphur pit.

Assignees

• Linde Ag

Inventors

• Hibbitt Ian
• Schreiner Bernhard

Classifications

• C01B17/0447 Primary

  Separation of the obtained sulfur · CPC title

• B01D2255/2092

  Aluminium · CPC title

• B01D53/8615

  Mixtures of hydrogen sulfide and sulfur oxides · CPC title

• C01B17/0456

  the hydrogen sulfide-containing gas being a Claus process tail gas · CPC title

• B01J19/245

  placed in series · CPC title