RIL develops new benzene extraction process

INDIA’S Reliance Industries (RIL) says that together with the Indian Institute of Petroleum (IIP) at Dehradun it has developed and commercialised a process for extracting benzene from light naphtha.

The new process has been demonstrated at Reliance’s Jamnagar refinery in India, which is home to two of the world’s largest fluid catalytic cracker units. The light naphtha produced by fluid catalytic cracking is a major source of benzene in blended gasoline, but regulators in the US have put pressure on producers to reduce the levels in fuel.

In 2011, following the introduction of the US Mobile Source Air Toxics gasoline fuel programme, which required refiners to meet an average benzene content of 0.62% by volume, RIL and IIP agreed to co-develop an extractive distillation process.

“It was evident that, in the near future, Europe and the rest of the world will also impose lower limits on benzene content in the gasoline,” RIL explained in a press statement.

Having reviewed the commercially available technologies for removing benzene from light naphtha, RIL found they suffered a number of disadvantages, including being too costly to build and operate, and a loss of value due to significantly lower benzene recovery.

An unproven option was extractive distillation technology that uses a solvent to extract benzene.

“It is very challenging to extract benzene from light naphtha using solvent because of its rapid degradation by polymerisation in the presence of reactive species such as olefins and di-olefins, and contaminants such as sulphur, nitrogen, chlorides, and oxygenates,” RIL reports.

The company says the partnership has been successful in developing a robust solvent, and piloting and scaling up an extractive distillation process that produce a raffinate product with less than 0.2% benzene by volume and which achieves 99% or higher recovery of benzene by volume for upgrading.

Technip was given the technical information package including a simplified process flow diagram, heat and mass balance and preliminary data sheets, so it could develop detailed engineering for the new process. RIL says it has carried out the construction of the new benzene recovery unit and its “flawless” commissioning, reporting yesterday that on 23 May the process produced raffinate at less than 0.2% benzene by volume.

RIL and IIP have filed a joint patent for the process, and have already received many enquiries to license the technology, RIL says.