High H2S content

Problem

Presence of H2S in the natural and associated petroleum gas results in great difficulties during industrial development of oil and gas fields. The elevated H2S content in gas may result in corrosion of equipment and pipeline metal or reduce the catalyst activity in the processes of carbon oxide conversion and ammonia synthesis. At the fields with elevated H2S content, H2S must be removed from the gas before pumping it into the main gas line. High H2S content is very dangerous for field and facility service personnel and require proper HSE preparation at all stages of planning and executing in oil and gas recovering processes to prevent potential catastrophic events. 


Alternatives

Traditional gas desulfurization methods:

  • absorptive
  • adsorptive
  • oxidative
The adsorptive methods feature high gas treatment degree (almost to 100 %) but have a considerable disadvantage, i.e., low velocities of gas passing the treatment equipment and low pressure. The absorptive methods, inversely, permit to achieve high velocities and large pressures, but their treatment degree is lower.


Solution

OZNA offers the Membrane technology in treatment of natural and associated petroleum gas. Technology the use the membranes to carry out to extract acid gases (СО2 and Н2S), after which the gas begins to meet the pipeline requirements, and to remove methane upon tertiary oil production for subsequent injection of carbon dioxide into the formation. The natural and associated petroleum gases often contain reactive or easily condensable components which considerably affect the membrane efficiency. To remove these components, maintain and/or monitor their content, and to prevent exceedance of the critical limit of membrane operability, an expensive pre-treatment is required. Moreover, the traditional membranes, used to remove the acid components during APG processing, gather heavy hydrocarbons in retentate, which results in their condensation commensurable with the membrane element volume.

Biological natural gas desulfurization

H2S content in the output gas may be less than 4 ppm. The capacity varies from about 100 kg to 40 tons of sulphur per day. The resulting biological sulphuric sludge can be used in agriculture or for further refinement to a higher-quality (99 % and higher) sulphuric product.

 

Results

The membrane technology permits to:

  • Process gases with H2S content of up to 5 % vol., at 100 % humidity and carbon dioxide content of up to 30–35 % vol.;
  • Reduce the H2S content in the treated gas to the conditions at which it can be used as a fuel gas for energy-producing plants, oil heating furnaces, boiler facilities;
  • Keep high HSE and Quality level to eliminate possible hazardous situations and events.
The plant capacity is up to 350 MMSCFD. The resulting biological sulphuric sludge can be used for further refinement to a higher-quality (99 % and higher) sulphuric product.

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