Economically Optimized Design of Methane Fermentation Systems for Swine Production Facilities
ABSTRACT AN economically optimum methane fermentation system is a function of the value of the energy produced and the cost to produce it. The point of maximum economic benefits occurs where unit energy production cost (UEPC), defined as total annual costs divided by net energy output, is a minimum. This study analyzed the operation of methane fermentation systems designed at various volatile solids (VS) loading concentrations and detention times for both mesophilic (35 °C) and thermophilic (60 °C) operating temperatures for swine production facilities. Dynamic computer simulations of the animal production facility and the methane plant provided yearly net energy production data which were used to determine the UEPC. From these computer simulations, a series of characteristic UEPC curves was developed for each loading concentration which shows the minimum UEPC as a function of detention time (DT).