Emerson's Coriolis flowmeters enhance quality and reduce costs

Unilever has installed six Micro Motion ELITE and F-Series Coriolis flowmeters from Emerson Process Management to measure the mass flow of silicone feedstock used to manufacture shampoo products. The flowmeters' highly accurate mass flow measurements have improved product quality and reduced production time by 10-15 per cent at the Unilever facility in Gebze, Turkey - one of the world's largest manufacturing plants for detergent, household and personal care products.

A new automatic silicone mixer line for shampoo products is part of a major investment programme by Unilever to meet increased demand for these products, including its Clear, Clear Cosmo, Dove and Elidor brands. The accuracy of the blending process on the mixer line is critically important to the quality of the final products, but after the new mixing line was started, Unilever discovered that the original Coriolis flowmeters (which were not Emerson products) were unable to measure feedstock flow because of entrained gas in the silicone.

To ensure production could continue with the required product quality, Unilever decided to use a process of weigh scales and load cells to replace the unsuccessful flow measurement system. However, the resulting handling, transport and storage of over 7000 barrels of silicone per year increased production time, operating costs, and health and safety risks. Wastage increased because 1-2 per cent of the silicone was left in the empty barrels. The equipment used to handle the barrels also increased plant energy usage and costs. Most importantly, the silicone measurement accuracy from the weigh scales was lower than expected and not sufficient to meet Unilever's exacting quality standards.

To eliminate the weighing process, Unilever required a highly accurate measurement system based on mass flow. However, the presence of entrained gas in the silicone feedstock used in the blending process made this a challenging application, as demonstrated by the failure of the previous Coriolis meters. This challenge was compounded by the need to operate at a vacuum of -700mbarg, to help separate bubbles from the silicone and improve the quality of mixing. Unilever evaluated several types of Coriolis flowmeters supplied by various vendors, but the tests were unsuccessful under these extreme operating conditions.

Low-frequency flow sensors

To address these issues, Emerson worked with Unilever to investigate how Micro Motion ELITE Coriolis flowmeters, which were not included in the previous evaluation, would perform in the same conditions. Emerson's Micro Motion ELITE Coriolis flowmeters feature low-frequency flow sensors that increase flow accuracy in the presence of two-phase flow. MVD (multivariable digital) technology considerably improves the accuracy and stability of the Coriolis signals from the flow sensor. Enhanced signal processing, as well as sensor stability and design, ensures accurate measurements even under entrained gas conditions. Extensive onsite tests proved the performance of the Micro Motion ELITE Coriolis flowmeter.

Atilla Bozkaya, Unilever project control and system design engineer, says: "Our tests concluded that Micro Motion ELITE Coriolis flowmeters are the only meters that can successfully measure silicone feedstock flow with high density bubbles. The meters maintained measurement accuracy despite operating in the -700mbarg vacuum needed in this application."

Installing the Micro Motion flowmeters enabled Unilever to eliminate the process of weigh scales and load cells, reducing operating costs by 17 per cent. In addition, the reduced handling of the silicone feedstock has reduced health and safety issues and minimised the risk of accidental spills that could damage the environment.

Based on the performance of Emerson's Coriolis flowmeters, Unilever installed an additional 12 Micro Motion ELITE and F-Series Coriolis flowmeters at Gebze when the capacity of the line was increased with two more mixers. Unilever is also expanding the use of Micro Motion products to other similar harsh applications and locations. For example, a Micro Motion ELITE Coriolis flowmeter was recently installed at a Unilever plant in Nigeria to measure detergent slurry.

To find out more about Micro Motion ELITE and F-Series Coriolis flowmeters from Emerson, please visit the website at www.emersonprocess.com/.