Model Predictive Cost Control

East Kansas Agri-Energy, LLC, in Garnett, Kansas, is not a company that takes things slowly. When a direction is plotted, it moves ahead with a goal clearly in mind. The company began as an energetic association of farmers and businesspeople interested in adding value to their crop production by converting corn into energy. Once this was goal was clear, the result was a full-scale ethanol plant capable of grinding 13 million bushels of corn, producing 35 million gallons of ethanol, and generating more than 170,000 tons of wet and distillers dried grain per year.

Energetic they were, completing the plant in a record time of eight months and lighting the boilers in June 2005. Within three days there were operating at full capacity. At that point, operators were already looking for ways to improve efficiency and overall output.

Filling growing demand

Demand for fuel ethanol continues to grow as more cities and states adopt policies encouraging or requiring the use of ethanol in gasoline. Dry grind ethanol production also produces distillers grains which are in demand as livestock feed.

Supplying these growing markets profitably means that manufacturers face great pressure to maximize production while controlling costs. Soon after it began operations, the team at East Kansas Agri-Energy began looking for ways to maximize production capacity and efficiency at its dry mill.

The team turned to Pavilion Technologies, a leader in model predictive control (MPC) technology and environmental solutions for the ethanol industry. Pavilion’s ethanol solution leverages the Pavilion8 software platform, enabling ethanol companies to drive operational performance while maintaining regulatory compliance. Powerful capabilities for modeling, control, monitoring, analysis, visualization, warehousing and integration are combined to provide targeted solutions, delivering faster time-to-value and greater cumulative value than alternative solutions.

Once the process improvements were deployed, ethanol production increased an average of 12% while reducing energy consumption.

East Kansas Agri-Energy first worked with Pavilion engineers to discuss and define their requirements, clarify expectations and identify anticipated benefits. The project included optimizing the plant’s evaporator, dryer and thermal oxidizer.

Pavilion implemented its ethanol solution to optimize dryer performance by predicting and controlling moisture. The solution uses a multivariable, non-linear controller to generate and execute dynamic optimization and control. Its continuous process control is able to maximize East Kansas Agri-Energy’s dryer production 24 hours a day, seven days a week to yield the highest possible returns with the plant’s current equipment configuration.

The controller accomplished a series of critical functions:

Shift drying load from dryer to evaporator;

Reduce heat losses of the thermal oxidizer hotbox;

Cut natural gas consumption in the thermal oxidizer;

Control the thermal oxidizer’s process steam header pressure; and,

Control the syrup evaporator (including syrup solids and steam consumption) in the beer column to manage and stabilize beer column separation with the residual evaporator steam.

Pavilion also customized the East Kansas Agri-Energy MPC solution to allow for higher distiller grain yield.

Results exceed expectations

As a result of implementing Pavilion’s ethanol solution, East Kansas Agri-Energy achieved three key benefits:

9.9% increase in energy efficiency;

12% increase in ethanol production and throughput; and

3.3% reduction in standard deviation in dryer moisture.

East Kansas Agri-Energy realized these significant benefits with minimal additional investment in plant equipment. The team estimates that the total value of the MPC installation is more than $2.5 million per year based on industry average marginal values and cost of natural gas. The impressive project results demonstrate the significant amount of capacity hidden in production processes, readily available with the right process control solution.

“The results we have achieved with Pavilion have far exceeded our expectations,” said Doug Sommer, plant manager, East Kansas Agri-Energy. “Pavilion’s ethanol solution has given us the edge we need to boost our production capacity, with minimal additional investment in plant equipment.”

Author Information

Michael Tay is a technical account manager for Pavilion Technologies. Reach him at mtay@pavtech.com .

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