Dry mill ethanol plants have traditionally used natural gas as the process fuel for production. Natural gas is used to raise steam for mash cooking, distillation, and evaporation. It is also used directly in DGS dryers and in thermal oxidizers that destroy the volatile organic compounds (VOCs) present in the dryer exhaust.The industry has made great progress in reducing energy consumption since its start in the 1980s; to produce a gallon of ethanol, today's dry mill plants only use about half of the energy used by the earliest plants. Still, natural gas prices are on the rise, and energy costs are second only to raw material costs in the dry mill process. These factors are driving the industry to undertake further efforts to reduce energy use, or to switch from natural gas to other fuels such as coal, wood chips, or even the use of DGS and other process byproducts.

A comprehensive review of state-of-the-art CCHP modeling, optimization, and operation theory and practice This book was written by an international author team at the forefront of combined cooling, heating, and power (CCHP) systems R&D. It offers systematic coverage of state-of-the-art mathematical modeling, structure optimization, and CCHP system operation, supplemented with numerous illustrative case studies and examples. CCHP systems are an exciting emerging energy technology offering significant economic and environmental benefits. Combined Cooling, Heating, and Power Systems: Modelling, Optimization, and Operation is a timely response to ongoing efforts to maximize the efficiency of that technology. It begins with a survey of CCHP systems from the technological and societal perspectives, offering readers a broad and stimulating overview of the field. It then digs down into topics crucial for optimal CCHP operation. Discussions of each topic are carefully structured, walking readers from introduction and background to technical details. A set of new methodologies for the modeling, optimization and control of CCHP systems are presented within a unified framework. And the authors demonstrate innovative solutions to a variety of CCHP systems problems using new approaches to optimal power flow, load forecasting, and system operation design. Provides a comprehensive review of state-of-the-art of CCHP system development Presents new methodologies for mathematical modeling, optimization, and advanced control Combines theoretical rigor with real-world application perspectives Features numerous examples demonstrating an array of new design strategies Reflects the combined experience of veteran researchers in the field whose contributions are well recognized within the energy community Offers excellent background reading for students currently enrolled in the growing number of courses on energy systems at universities worldwide Timely, authoritative, and offering a balanced presentation of theory and practice, Combined Cooling, Heating, and Power Systems: Modelling, Optimization, and Operation is a valuable resource forresearchers, design practitioners, and graduate students in the areas of control theory, energy management, and energy systems design.