Coriolis meters are Turkish delight for Unilever plants 06 December 2012

Unilever is reporting that Micro Motion Elite and F-Series Coriolis flowmeters are providing accurate results under vacuum conditions, despite challenging two-phase flow conditions involving entrained gas.

The firm commissioned six of Emerson's Coriolis flowmeters to measure the mass flow of silicone feedstock, and says the result has been improved product quality and production time reduced by 10—15% at its plant in Gebze, Turkey.

Atilla Bozkaya, Unilever project control and system design engineer, explains that the plant – one of the world's largest manufacturing detergent, household and personal care products – had recently installed a new automatic silicone mixer line. However, after the line started, plant engineers found that existing third-party Coriolis flowmeters could not measure critical silicon feedstock flow, because of entrained gas problems.

Engineers replaced the Coriolis devices with a load cell system, but then found handling, transport and storage of more than 7,000 barrels of silicone per year was increasing production time, operating costs, energy consumption and health and safety risks.

Wastage also increased because 1—2% of the silicone was left in 'empty' barrels.

Most important, however, silicone measurement accuracy from the weigh scales was poorer than anticipated and not up to Unilever's quality standards, says Bozkaya.

Moving back to Coriolis mass flow was always going to be the best plan, but Bozkaya makes the point that the previous meters had failed – and that difficulties were compounded by the requirement to operate at a vacuum of -700 mbarg, to help separate bubbles from the silicone and so improve mixing quality.

Unilever evaluated several types of Coriolis flowmeters without success, but then came across Emerson Micro Motion Elite Coriolis flowmeters, which are based on low-frequency flow sensors and multivariable digital technology (MVD) that together can significantly improve flow accuracy and stability in two-phase flow.

"Our tests concluded that Micro Motion Elite Coriolis flowmeters are the only meters that can successfully measure silicone feedstock flow with high density bubbles," states Bozkaya.

"The meters maintained measurement accuracy, despite operating in the -700 mbarg vacuum needed in this application."

The result: Bozkaya's team was able to remove the weigh scales, so cutting operating costs by 17%, while also reducing silicone feedstock handling, and hence also health and safety, and environmental risks.

Unilever has now installed an additional 12 Elite and F-Series Coriolis flowmeters at Gebze, following expansion of the line to meet increased capacity requirements.

Bozkaya says Unilever is also expanding the use of Micro Motion meters to other similar harsh applications and locations around the world. He cites one Elite Coriolis flowmeter recently installed at a Unilever plant in Nigeria to measure detergent slurry.

Brian Tinham

Related Companies
Emerson Process Management

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