Model Based Control for Dryer Energy Conservation

Producers of solid and liquid biofuels need to reduce both capital and operating costs to achieve unsubsidized cost parity with fossil fuels. Many biomass feedstocks destined for conversion platforms must be dried, however, the capital cost for dryers is high due to long residence times and the operating cost is high due to system inefficiencies. Consistent and reliable operation of biomass dryers is problematic across emerging and rapidly expanding biofuel firms due to inexperience of operators and lack of knowledge about drying characteristics of their feedstocks. This project will develop advanced, retrofit-able dryer control systems utilizing modern sensor equipment as well as high pressure low temperature down draft drying methods that optimize final moisture content, energy input, and capital costs that can be applied to both new and existing dryers. During this project we will develop a table of drying properties for bioenergy feedstocks of switchgrass, miscanthus, sorghum, high-moisture baled corn stover, and poplar chips. We will also formulate a physics-based drying model for moving bed dryers relevant to a model based control system in order to minimize drying time and energy consumption.Products of this research will include a table of important drying parameters for select crops as well as a model based control system for dryers. The technologies resulting from this project can immediately be implemented in current biopower and solid biofuel gasification facilities as well as future second generation thermochemical facilities. These technologies will likely reduce the capital by 30% and operating costs by 25% resulting in dramatic biofuels production cost reduction.