Accurate flow measurement of scrubber effluent used in the single superphosphate (SSP) manufacturing process has been a challenge at Incitec Pivot’s Cockle Creek plant for a long time.
Incitec Pivot are manufacturers and suppliers of agricultural nutrients and the Cockle Creek plant manufactures 250,000 tons of superphosphate for distribution to farmers throughout New South Wales.
Scrubber effluent is a key element in the manufacturing process and its use provides environmental benefits. Reusing the effluent allows the Cockle Creek plant to reduce the amount of fresh water used and also eliminates the need to discharge it off-site. The accurate flow measurement of the effluent is a critical factor in optimising the process. The harsh physical and aggressive chemical properties of the scrubber effluent provide many challenges for the plant operators due to the presence of silica dioxide and hydrofluorosilicic acid.
Over the years, many modifications were made to the application to get reliable flow measurements.
Following are some of the changes made to the application:
- Different earthing arrangements to prevent earth faults through silica scale buildup.
- Introduction of low friction, high temperature plastic to limit scale buildup in pipes.
- Changes to maintenance routines introduction of on-line calibration checks.
Despite numerous trials of different brands of electromagnetic flowmeters and ultrasonic (time-of-flight) flowmeters, the problem of erratic readings remained.
Partha Gupta, Endress + Hauser Sales Engineer, took on the challenge of providing a solution. Gupta visited the Cockle Creek plant and obtained samples to analyse and test. He recommended a Promag 53 electromagnetic flowmeter with PTFE liner, tantalum electrodes and advanced evolution software.
As the flowmeters in service at that time were proving unreliable, Incitec Pivot purchased and installed a Promag 53 electromagnetic flowmeter. After a month of positive results, the company purchased and installed another Promag 53 electromagnetic flowmeter in the second scrubber effluent pipework. Nine months later, both flowmeters were providing reliable and accurate measurements.