Wireless Technology Designed for Demanding Applications Controls pH Levels in Rotating Drums
Hello everyone. I’m Stéphane Canadas, Analytical Specialist at Emerson Process Management. A customer of ours in Europe has an application that demonstrates the importance of having a wireless technology that can meet the need of demanding field networks. The company performs sugar processing. While your application may be different, if you have a demanding application, there are lessons to be learned from this example.
As part of this company’s production process, clean, sliced beet is pumped into one of three rotating drum diffusers and then mixed with water at approximately 85o C to extract the sugar. pH levels of the solution must be monitored within the drums to optimize the soaking period and ensure it has the correct pH level before it passes through the next stages of purification. In the past, the company performed the pH measurements manually with solution samples taken every hour and analyzed in a laboratory. As you can imagine, this was very time consuming and did not provide immediate or continuous information as needed. Collection of the sample was difficult, requiring an operator to open a valve on the rotating drum, fill a bottle from the port and close it, all in a few seconds while the drum was on the lowest part of its rotation. At times, the port would be blocked by beet fibers preventing a sample from being taken for several hours forcing the process to run blind. Has your plant ever experienced anything similar? If so you know how unsatisfactory such a procedure can be.
The customer wanted to install a continuous automated monitoring system. They first tried a wired installation using a slip ring but the connection points for both power and data proved to be very unreliable causing data signals to be lost. They next set upon a wireless solution to solve the problem but wanted any wireless system they purchased to perform a number of tasks across the plant. It was important, therefore, that they selected an open standard technology that would not lock them into a single vendor.
After reviewing a range of systems, the customer settled on the Rosemount Analytical Model 6081-P wireless pH transmitter. The transmitter, along with a 3500 SMART pH sensor, was installed on the rotating drum. Because of the inherent ease-of-installation of the Emerson field network system, the wireless devices began transmitting data the minute they were attached to the drum. Since the sensor is preconfigured in the lab by Emerson, it received its specific setup through the wireless network and began immediate operation. Measurement data from the device is transmitted every sixty seconds from the sensor to a Smart Wireless Gateway and then transmitted to the customer’s DCS providing the much-needed continuous measurement.
Initially, the wireless system just provided continuous pH measurements to be viewed by the operator who then made manual adjustments to control the pH levels. However, since the initial four-week trial period proved so seamlessly integrated and reliable, they are now using the wirelessly transmitted data to control the pH level in the diffusion drums automatically.
The bottom line is that with the selection of a field network wireless system with the configuration, security, reliability and simplicity required by demanding applications, this company was able to significantly improve productivity and process quality while reducing energy use, water and rework. These results were achieved in a highly demanding rotating drum application. The decision to move from monitoring to control is strong testimony in the company’s confidence in the Model 6081-P and Emerson Smart wireless field network solution. We might call that a sugar of a deal.