SULREC: Sulphur Recovery System

Sulphur Recovery

SULREC technology is a partnership between Engineers India Limited (EIL), a Government of India engineering, consulting and EPC firm; and Permionics Membranes Private Limited (PMPL), a leading water treatment solutions provider. This patented technology offers an innovative process for maximizing sulphur recovery for important Oil & Gas industry applications.

There are two current applications for this technology

Current State- Natural Gas

Most Natural gas sources are contaminated with Hydrogen Sulphide (H2S) ranging from 0.5% to 3% w/v. The conventional process is to pass the gas through the Amine column where the Carbon dioxide and H2S get absorbed and the Sweetened Natural gas is taken further for processing. The off gas from the Amine column, also called Acid Gas, will generally contain 90% CO2 and 10% H2S. This gas is taken to the oxidizer where H2S gets converted into Sulphur in the form of fine colloids. A proprietary surfactant is added to aid
the settling of the particles. However, the very fine particles do not settle and float to the surface.

Current State – Biogas Feed

Biogas contains 60-65% Methane, 30-35% CO2 and 3-5% H2S. This is produced usually in Municipal Biogas plants, waste to energy Solid waste plants and some industrial waste treatment plants. The gas comes out at atmospheric pressure and needs to be sweetened so that it can be used as clean fuel. The LOCAT process is a favoured method of treatment where the gas is directly scrubbed with the catalyst solution which oxidizes the H2S to elemental sulphur. In most cases the colloidal solution of elemental sulphur and catalyst is passed through a bag filter where the sulphur is filtered out and disposed, while the catalyst solution is regenerated and recycled. However when the quantity of Sulphur is in the range of 5 tonnes per day and higher it becomes economical to recover the sulphur.

SULREC Solution – Natural Gas

Here the supernatant containing these fine colloids is taken to the SULREC system where the colloids are concentrated in a ultrafine cross flow filtration process where the filter element has a pore size as low as 50nm. The concentrated slurry is then sent to a continuous filter press where a sulphur cake is produced with < 10% moisture and 99.5% purity. The filtrate is sent back to the column after treatment protocol specific to the feed source and desired output.

SULREC Solution – Biogas Feed

In the SULREC system the colloidal solution is concentrated and then filter pressed into a cake to produce pure Sulphur. The filtrate is the catalyst solution which is regenerated and recycled.

PERMIONICS can offer the complete package – the catalyst process and the recovery system. Or it can integrate the recovery process into an existing LOCAT process.

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