Evonik chalks up APC gains

London - German-based Evonik Industries is employing advanced process control (APC) techniques to improve the cost effectveness of its speciality chemical plants in Marl and Essen, in the Ruhr region and in Darmstadt as well as in Hanau-Wolfgang in the Rhine-Main Area. These efforts are centred on achieving performance gains solely through the use of APC software, which is supplied by AspenTech.

Dr Kai Dadhe, a project manager in Evonik 's automation engineering unit, is responsible for process optimisation within the Chemicals Business Area. Acting as an internal service provider, his team produces optimisation proposals for the group’s plants. The most important criteria for this process are improving plant throughput, reducing specific energy consumption and keeping manufacturing costs to a minimum.

The Evonik team's is focused on making improvements exclusively through the use of software - and not by replacing components or adding them to the plant - so that benefits are delivered by integrating engineering and manufacturing models in order to tune the performance of plant operations.

“We are beginning to institute a unique approach to continuous improvement at Evonik which we call advanced process operations,” said Dadhe. “I'm confident that we can get a lot more out of our chemical processes by using software solutions.”

Evonik started down this path about 10 years ago when, as the former Degussa, it began to employ  AspenTech software to standardise on one platform for production data management.

“In our business, plant throughput is our primary concern, though we do keep a close watch on energy consumption. With our data historian, we have the data that process engineers need both to simulate ‘what if’ situations and to identify bottlenecks in critical operations so that we can increase throughput," said Dadhe. "Operators can use trending data to detect potential problems like catalyst deactivation in a reactor which would drive down line production rates. We are moving towards predictive maintenance to detect problems like this and to get back to running to peak performance more quickly."

The software support across all the different areas involved, from understanding the process, evaluating the data and working on the project through to implementation and follow-up, continues Dadhe. In his work, he uses Aspen InfoPlus.21® for production management and execution and Aspen DMCplus as well as a new APC, in particular aspenONE V7 Manufacturing & Supply Chain (MSC).

Evonik used Aspen InfoPlus.21 for archiving process data. All the measurements are incorporated into the software which allows them to be evaluated and offers important benefits in the form of data compression, defining key indicators and process analysis.

“In my opinion, systems of this kind are essential for an understanding of the plants and processes. They provide valuable details, including simulations of the use of the plant and the corresponding load curves,” explained Dadhe. He also feels that the software's intuitive user interface is a major benefit and makes process optimisation much easier.

“One simple yet highly effective example is the process optimisation in distillation columns, which are a part of almost all chemical plants. We often find only a limited number of continuous quality measurements and instead an infrequent number of manual laboratory measurements. This kind of sparse information can lead to sub-optimal control and may result in quality issues with a product.” In order to resolve this problem, continuous measurements are needed in order to be able to improve the plant operation.

For such projects, Dadhe makes use of different sources of information, including laboratory analyses and parameters such as pressure and temperature. Using simulation models they can generate accurate continuous predictions of key process attributes to close the gap in information available from physical instrumentation and infrequent lab analyses.

He also uses AspenPlus software, which is intended for plant design and simulation and is in use in a number of key areas within Evonik. The software simulates different processes in the plants and provides information about the optimum design and productivity of the plant.

As Evonik currently uses AspenPlus only for plant design and not for plant operation, Dr Dadhe produced an additional simulation plan for one of the plants referred to earlier. This simulation generated additional key performance metrics which were then also incorporated into the database. “All the information we need to drive improvements is available internally but it is disbursed widely throughout the organisation and needs to be properly integrated. Having access to a complete data set in one place enables us to optimise our processes much more effectively.”

The analysis results from Aspen InfoPlus.21 provided Dr Dadhe with the necessary data to implement a new automation solution which uses the same technology implemented in aspenONE V7 MSC to control the physical constraints.

“Using software to automate and control the plants is far more efficient than doing it manually. As a result, improvements of this kind are highly profitable,” said Dadhe. For example, the optimisation and control of the distillation column resulted in an increase in throughput of around two per cent and also resulted in a deeper process insight and understanding. In the case of this project, the company made a return on its investment in less than a couple of months.

Dadhe believes that there is still potential to be exploited at Evonik in the future in terms of driving even greater levels of operational efficiency. Most importantly, he would like to see the consistent and continuous use of data in order to ensure that all phases of the plant, from planning to operation, are made even more effective.

“The fact that we use AspenTech software in almost all the relevant areas of our business means that it would not be a problem in technical terms to combine the information from the simulation, the planning process and plant operations. One of our aims is to increase use of AspenPlus in the field of advanced control.”

Enhancements made to the quality of operational processes and capacity at Evonik as a result of Advanced Process Operation projects – including most recently the new State Space Control application implemented using the Aspen Control Platform within aspenONE V7 MSC - have translated into measurable benefits. The ability to achieve real-time optimisation – based on the implementation of rigorous models – enabled a return on investment to be achieved within a period of six months to a year. Furthermore, yield and production have increased by two to five percent and operator interactions have been reduced by more than 50 per cent. Finally, the engineers’ level of process knowledge has grown.