Rockwell Automation and Endress + Hauser Partner to Increase Efficiency at Bio-Fuels Plant

Biodiesel as an alternative energy source is not a new concept. Today, thanks to rising energy   prices, increasing dependence on foreign oil and heightened concern regarding the environmental impact of fossil fuels, biodiesel is now a viable, cleaner alternative to traditional diesel fuel.

One company is doing its part to make biodiesel more readily accessible to consumers. In 1996, West Central Cooperative built its first biodiesel plant in Ralston, Iowa. The co-op was interested in bringing a new product to market using the oil byproduct of meal, one of its existing soybean products. The offering tapped into a new market of alternative fuel for mobile diesel engines, mostly for farming, industrial and fleet industries.

Back in 2002, when the co-op was operating as a single, multiproduct plant in Ralston, now known as Renewable Energy Group automated most of its biodiesel-making process using a programmable controller (PLC). Pulling real-time data from a programmable controller and human-machine interface, the co-op used a basic reporting system that allowed the press plant to buy beans from the elevator in real time, while calculating the yield of oil meal to bushels used.

However, the plant was producing biodiesel one batch at a time, which resulted in down time that required operators to wait for tanks to be emptied before continuing production. In addition, some steps of the process were performed manually, such as adding bags of catalyst chemicals to initiate the biodiesel-making process or moving hand valves to route each batch to the next tank during production.  Renewable Energy Group® needed to increase operational efficiency, monitor the quality of glycerin byproduct from the biodiesel production process, and make sure the biodiesel it produced exceeded current industry standards. In addition, regardless of where the crude oil originated, the end biodiesel needed to be of the same quality and consistency. To help meet these goals, it sought an automated process control platform to produce biodiesel with system monitoring.

They installed two Allen-Bradley® ControlLogix® programmable automation controllers (PACs), based on the Rockwell Automation Integrated Architecture™, to run each plant. Unlike their previous controller, ControlLogix PAC is multidisciplined, meaning that it can manage discrete, batch, process, motion, safety and drive capabilities – all on a single platform.

The Rockwell Automation relationship with process instrumentation provider, Endress+Hauser made the solution even more effective and easier to implement. With preferred integration between Endress+Hauser process instruments and the Rockwell Automation Integrated Architecture, Renewable Energy Group can help protect its investment with assured interoperability. The relationship provides a wide range of pre-integrated, pretested, standards-based measurement, automation and information solutions.

Additionally, Custom-enclosed Allen-Bradley PowerFlex AC drives connected to the ControlLogix controllers via DeviceNet help manage flow rates throughout the refining process, helping to maintain the proper tank levels during each step of the process. The controller also is connected to an intrinsically safe Allen-Bradley FlexEx™ I/O module via ControlNet, allowing biodiesel processing data to be collected from inside hazardous areas of the process plant and monitored remotely.

By establishing a standard control system that acts as a model template for all of its existing and upcoming biodiesel plants, Renewable Energy Group has reduced its design, installation and training costs.  Additionally, start-up and troubleshooting time has been reduced, allowing Renewable Energy Group to get biodiesel to market faster.