Hydrogen Sulfide Removal Process

Removing Hydrogen Sulfide from Natural Gas Wells

1. Introduction

Removal of hydrogen sulfide is becoming increasingly important because of the increased need for greater natural gas production.  There are thousands of wells in this country that have been closed or are not producing because of the high level of H2S comprised in their gas streams and no economical way to remove it.  Hydrogen sulfide is a highly corrosive gas and often the cost of ongoing maintenance and replacement of pipelines, tubing and other equipment make the prospect of operating natural gas with high levels of H2S to be breakeven at best. 

2. The Procedure

There is a simple and low cost technology for the removal of virtually all the hydrogen sulfide from any natural gas or liquid stream. This method works at ambient temperature and pressure.  The device creates a bath of reacted water and the gas flows from the bottom of the device thru a catalytic chamber and water bath then out the top of the device. Hydrogen sulfide present in the sour gas gets absorbed by the reacted water and is subsequently converted into elemental Sulphur and iron sulfide. The Sulphur thus generated is removed from the water bath by filtration. The reacted water is again passed thru the device and recycled for further cleaning of sour gas.

3. The Chemistry

H2S when dissolved in the aqueous medium is ionized to H+ and S2- The Sulphur ions can be oxidized by polyvalent metal ions such as those of iron, which can exist in both ferric (Fe3+) and ferrous (Fe2+) state. When the Sulphur ion comes in contact with ferric ion complex, it gets oxidized to elemental Sulphur and is precipitated.

2Fe3+ + S2- 2Fe2+ + S

The ferrous ions are later oxidized to ferric ions by reaction with oxygen in the atmospheric air.

4Fe2+ + O2- 4Fe3+ + H2O

4. Process Features

•  The process is highly selective to H2S. 

•  H2S is converted into elemental Sulphur, which has commercial value.

•  Low H2S concentration at the outlet (< 2 ppm).

•  Works at ambient temperatures with easy start up and   shut down procedures

•  Capable of handling fluctuations in gas flow rates and H2S percentages.

•  Low running costs as scrubbing solution is completely regenerated. 

The operational schematics of the plant are as shown in the flow diagram. The gas scrubbing is a multiple stage process in which the sour gas is first passed through a wet chamber where it mixes with the reacted water that had been been pumped thru our proprietary technology.  Then the water after mixing with Sour Gas is filtered for removal of the contaminants. The sour gas is then demisted by the coalecer. The clean gas is taken out from the system and continues towards the sales line. The H2S present in the gas is absorbed by the reacted water and is later converted into elemental Sulphur. The Sulphur is removed by filtering using the filter system.

Fresh air is introduced into the Water tank
to provide the levels of oxygen to react
with the catalyst also it provides
regeneration for the Dry Catalyst.