Figure 7 starch costs by process area 1999 vi32

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Figure 7. Starch costs by process area (1999$) VI.3.2 Lignocellulose Costs by Area While not as large as the corn feed costs, the cost for stover feedstock is still significant. In this model, steam costs appear as the largest single area of capital for a FBC and turbogenerator system, and cooling water and chilled water are produced via a cooling water tower and chiller, respectively, which appear in the utilities capital section. For this process, pretreatment is the largest steam consumer, followed by distillation. Enzyme production consumes 32% of the 9,615 kW of power used in the plant to compress the air fed to the cellulase fermentors and to agitate the fungal slurry. -$0.50 -$0.30 -$0.10 $0.10 $0.30 $0.50 $0.70 $0.90 Cost per Gallon of Fuel Ethanol Depreciation Process Electricity Variable Operating Labor, Supplies, and Overhead Co-products Feedstock Feed Handling Saccharification Fermentation Distillation Solid/Syrup Separation Storage/Load-out Wastewater Treatment Utilities Corn at $1.94/bushel
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25 Fermentation requires 15% of the electricity to agitate and pump the solids-containing slurry. Electricity consumption is estimated from vendor quotes, engineering firm reviews, and comparison with similar applications. While an estimate, it is a rigorous one, including every piece of equipment for the plant down to spares. Comparing the electricity consumption of the two processes, fermentation power is ten times higher in the lignocellulose process due to the higher solids concentration and longer residence time, and there is extensive power usage in the cellulase production area for air compressors. Pretreatment reactors require more power than the mash cookers in the starch process due to solids concentration. Figure 8. Lignocellulose costs by process area (1999$) VII Future Impact of Co-Products Co-products can have a substantial impact on the economic viability of a low-value product like ethanol. Changing market environments, regulatory action, and political issues can affect the entire product slate from a plant. Ensuring that a market exists for current and potential co-products after an industry is robust is an important planning exercise in the design of commercial processes. -$0.50 -$0.30 -$0.10 $0.10 $0.30 $0.50 $0.70 $0.90 Cost per Gallon of Fuel Ethanol Depreciation Variable Operating Labor, Supplies, and Overhead Process Electricity Total Process Electricity Co-products Feedstock Feed Handling SSCF Distillation Solid/Syrup Separation Storage/Load-out Wastewater Treatment Utilities Pretreatment Enzyme Production Boiler/Turbogenerator Stover at $35/dry ton
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26 VII.1 The Future of Starch Process Co-Products VII.1.1 DDG As previously stated, DDG is the principal co-product of the dry mill ethanol industry. DDG is 27% protein and is currently sold as animal feed. Unfortunately, the animal feed markets are now becoming saturated and the price of DDG has dropped from more than $150 per wet ton in 1995-1996 to $86 per wet ton in the 1998-1999 market year.
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  • Spring '10
  • BLANCHE
  • The Land, ........., corn ethanol industry

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