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Amarinth’s £1 million answer to sulphur pumping challenges

Amarinth, a company specialising in the design, application and manufacture of centrifugal pumps and associated equipment, has invested over £1 million (€1.4 million) in designing and launching a new range of API 610 VS4 vertical sulphur pumps for the oil and gas industry.

Elemental (pure) sulphur is a valuable by-product recovered during the refinement of oil and gas and is sold on to be used in the manufacture of many products including fertilisers, chemicals, pharmaceuticals, asphalt and concrete.

The sulphur is extracted and transported around the processing plant in liquid form at a temperature of some 140 degrees Celsius, but it only remains in its liquid state suitable for pumping within a narrow temperature band of approximately ±20C.

At lower temperatures the liquid will start to revert to a solid and at higher temperatures its viscosity actually increases due to the formation of polymers, all of which creates unique challenges for sulphur pumps.

To date, many sulphur pumps have been simple adaptions of VS4 vertical pumps or other standard designs but these have brought with them maintenance and reliability issues for operators.

Three years ago, Amarinth decided to produce the API 610 VS4 vertical pump that could meet the challenges of reliably pumping molten sulphur.

Amarinth first undertook a detailed study of existing sulphur pumps (usually simple adaptions of existing designs) and how they were used and maintained to determine where issues occurred.

Users reported high incidents of bearing failures, shaft problems and having to run significantly shorter maintenance periods to try and minimize failures, all of which resulted in increased downtime for the plants.

According to Amaranth, the design of the new pump includes a new arrangement for the shaft bearings and lubrication film, which reduces the previous bearing and shaft issues, a redesigned jacket to maintain the temperature of the molten sulphur and hence its viscosity, a new design of impeller, a modular column design that enables rapid production of bespoke pump lengths and simplifies maintenance, and improved access to make regular maintenance faster and less disrupting.