Intelligent process control designed to lay the foundations for a digital plant
How Siemens’ total integrated automation and process control solutions are helping optimisation of acrylamide and polyacrylamide production at Kemira’s Bradford factory.
Water is one of the most important resources to sustain life, it is used in everything we produce or use. A global expert in chemical solutions with a manufacturing presence in over 40 countries, Kemira serves water intensive customers in the paper, oil and gas, mining and water treatment industries. On its Bradford site of approximately 50,000 sqm the company produces a range of polyacrylamide products which are used for the cleaning of municipal and industrial wastewater.
Polyacrylamides are powdered solid products that act as flocculating agents, binding with impurities and small particles to speed up the separation of solids and liquids in a multitude of industrial processes. Acrylamide is the essential raw material in the polymerisation process via which polyacrylamides are manufactured, and for many years the acrylamide was sourced from a Kemira plant in The Netherlands, with up to ten tanker loads per day making the journey across the North Sea to Bradford. To improve the use of resources and minimise waste the company set out to bring the manufacture of acrylamide on site.
For a plant that operates 24/7 and is a worldwide distribution hub for over 3000 customers, selection of the technology solution was key, but the solution was not difficult to find; two of Kemira’s polymer production sites in North America and Europe were successfully using Siemens distributed control system (DCS), SIMATIC PCS 7, for plant automation. This prompted the Kemira UK team to engage with Siemens in the country to tender the solution.
“There were a number of factors that led to this project,” explains Graham Scarborough, Process Technology Team Leader for Polymer Manufacturing at Kemira. “We knew that the acrylamide unit at the Dutch plant was nearing the end of its life, so it made sense to remove the reliance on a long-distance supply route and eliminate the associated environmental and financial costs. In addition, we had a role model in the Kemira site at San Giorgio in Italy, which was already producing its own acrylamide through a much more energy efficient enzyme-based process.”
SIMATIC PCS 7 is a fully integrated and engineered DCS solution used in chemical and process plants across the world. Management and control of processes are at the core of the solution, ensuring there is consistent performance, high availability and safety.
The Bradford project involved planning for the safe offloading and storage of the raw material, acrylonitrile; creating three reactors in which acrylonitrile would be converted to acrylamide; and constructing two large tanks to store the acrylamide that was produced.
The SIMATIC PCS 7 system was integrated into the new plant alongside Siemens intelligent field instrumentation for accurate process measurement. This provided a fully integrated Siemens solution that covers both the control and measurement aspects of the process. The Profibus communication protocol was used for data communication between field devices and the DCS, creating the perfect opportunity for Kemira to gather data to provide key insights into their production process.
The selection of the technology vendor and solution, alongside the collaborative way of working, was a significant factor in the project’s success.
“We found the whole team to be extremely supportive and that was a significant factor in our decision to select PCS 7” added Scarborough.
A workstation located in the new building enables the acrylamide plant operator to view every aspect of the plant functionality. This computer is connected to the site control system network and linked with an archive software that collects and stores detailed operational data.
“Information and the ability to run the process and to look back at our historical data is very important,” says Paul Turfrey, Technical Manager. “We can use this information to track our daily activity and aim for continuous improvement.”
“The SIMATIC PCS 7 system allows us to drill down at each step of the production sequence to see detail such as the opening and closing of valves, flow rates, temperatures and pressures. The use of Profibus instruments connected to PCS 7 means that for almost any issue that arises we do not just get an alert, we also understand the exact nature of the problem, which represents a significant step forward from the more traditional hard-wired systems.”Graham Scarborough, Process Technology Team Leader
The new plant began producing acrylamide in June 2017 and, by capturing and analysing data from the PCS 7 system, Kemira has been able to drive significant improvements in the efficiency of the process, achieving a near 50% increase in peak production rate. Cycle time has been significantly reduced and new weekly and monthly site production records have been set.
“We are self-sufficient in acrylamide production and we have eliminated a yearly total of 1600 tanker deliveries. In addition, the process is quicker and runs at a lower temperature. With a safe and efficient plant, we can focus on improving the manufacturing process and reducing batch times further,” concludes Scarborough.
There is designated space for future expansion within the new plant, with the potential to add a fourth reactor and additional processing equipment. The chiller plant has also been designed with one eye on potential future demand and the scalable design of the control system means that any new instrumentation can quickly and easily be incorporated.
“Siemens was able to supply a complete solution, and with the strong relationship we’ve built during that time, we further look forward to helping Kemira develop the acrylamide plant in the future,” comments Ian Elsby, Head of Chemical Industry UK and Ireland at Siemens Digital Industries. “From training and implementation through to maintenance we are committed to full lifecycle support, enabling Kemira to make further improvements.”
“The combination of Kemira’s process expertise and the Siemens integrated solution has created efficiency and enabled Kemira to exceed targets” says Steve Leech, Business Manager for Process Control Systems at Siemens. “Furthermore, the capture of key manufacturing insight by the Kemira team, creates the foundation for future information led decision making and production assessments.”
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