Ethanol makers turn to advanced control to cope with demands

Paul Boughton

Adkins EnergyBadger State Ethanol and East Kansas Agri-Energy are the latest group of USA-based ethanol producers to invest in modern process control technology in order to improve their productivity and efficiency.

Each has signed a contract with Pavilion Technologies for its Advanced Process Control (APC) solutions that have been shown on other sites to reduce energy costs by up to fivepercent and increase production by threepercent in between two and four months of installation.

More than 14 ethanol manufacturers are now using APC solutions to achieve emissions compliancereduce energy costsincrease ethanol productionand enhance product yields.

“In just a yearwe’ve seen an excellent return on investment from Pavilion” said David Culverplant manager for Glacial Lakes Energy (GLE)which is one of the 14.
GLE produces over 47mgallons/y of ethanol at its facility in WatertownSouth Dakota. Formed in 2001GLE is owned and operated by Glacial Lakes Corn Processors (GLCP)a cooperative. The company is currently overseeing the production of another 50mgallon/y plant at Redfield in the same state.

The GLE process begins when whole corn first goes to a hammer mill before being mixed with fresh water and heated by steam in a jet cooker. Next comes the liquefaction stage. One stream from here goes via the mash cooker. This stream then has yeast added before reaching the fermentation vessels. The other route involves the addition of enzymes before the fermentation phase. Next comes distillation to 190proof. A molecular sieving process followed by the addition of fivepercent gasoline is the last stepgiving a final product of 200proof ethanol.

“Pavilion enables us to control the distillation columns and molecular sieves processeswhich are challenging to manage optimally and yet critical to achieve our operating objectives – morehigh quality ethanol for less. Furthermorewe are able to continuously reduce our energy usage. And in today’s marketplacebeing able to produce more ethanol at higher yields equals real money” added Culver.

As the demand for alternative fuels grows and manufacturers seek strategies to quickly capitalise on record-high ethanol pricesPavilion provides an effective technology solution to enable the production of more high quality ethanol for less. Simultaneouslyethanol manufacturers can drive down energy costscombating the sky rocketing prices for natural gas. This helps ethanol producers achieve two key goals: more efficient use of energy and a greener end product.

Pavilion’s software – Pavilion8 – combines powerful predictive and dynamic control capabilities that allow manufacturers to more effectively control complex processes exhibited in the production of ethanol. With Pavilion's control solutionethanol manufacturers have improved the performance of the dryerevaporatorthermal oxidisermole sieve distillation and other stages of the production cycle. The company says that most customers report a payback in 2–6months on projects completed in 8–16weeks.

An integrated software suite

Pavilion8 is an integrated software suite that enables process manufacturers to drive operational performance to desired business objectives while maintaining regulatory compliance. It combines technologies for modellingcontrolmonitoringanalysisvisualisation and integration to provide multiplevalue-driven applications for targeted industry solutions.

Modelling simple and complex processes is the foundation for all Pavilion8 applications. For over 15yearsthe company has been a leader in the development and deployment of advanced non-linear modelling technology ranging from concentrate density in dried milk evaporators to melt flow rate in polypropylene reactors.

Powerful data preprocessing tools allow data from multiple sources with different frequencies to be synchronised into a single data set for modellingproviding better modelsfaster. According to the companyits hybrid modelling approach extends standard neural network techniques to enable systematic use of both process data and first-principles equations in model development. Thisit saysdelivers high fidelity process models that are computationally efficient for real-time prediction and controlthat are also easy to maintain.

Pavilion8 integrates non-linear modelsmultivariable controland advanced optimisation into one algorithmproviding tighter control and optimisation. Through advanced modelling capabilitiesPavilion8 parametric control provides precise management of processes exhibiting varying dynamic behaviour over the full operating range. This allows manufacturers to stretch operating ranges to meet customer demandsor develop new products to expand market reach. The integrateddynamic non-linear optimisation permits manufacturers to drive processes to optimum conditions based on economic constraintsprocess constraintsor equipment constraints. It also promotes faster product grade transitionsthus reducing off-spec production and providing greater flexibility in production runs.

Pavilion8 provides a modernbrowser-based user interface that presents application views and summary reports based on a user's organisational role. These views allow operators to view real-time controller performanceengineers to configure process models and controller parametersand managers to observe key performance indicators of production and quality. The new interface fosters rapid product adoptionreduces training costssimplifies troubleshootingand facilitates improved application performance. Users can also compare historical performance with current conditionsallowing them to detect long-term trends of key variables over a selectable time horizon.  

Steady state optimisations can also be performed by setting output variable targets and letting the model determine optimum input variable targets. Pavilion8 also exploits model-based analytics to provide a new dimension in performance management. Key performance indicators (KPIs) are embedded within the control and compliance applications to automatically collectaggregateand calculate measurements. The KPIs are historicreal-timeor predictiveenabling all levels within the plant to proactively manage to business objectives.

Finallyit also collects and aggregates data from real-time resources including historiansdistributed control systemsand sensors. Once acquireddata can be manipulatedcalculatedand stored within Pavilion8’s metadata repository. The information is the basis for a variety of complianceperformance monitoring and reporting applications. It supports the insertion of comments or annotations into the data repositoryallowing users to provide explanatory information for modified data that is atypical of normal operations.