INVESTMENT, IRREVERSIBILITY, AND UNCERTAINTY IN ENERGY BEET–BASED ETHANOL

This study evaluates optimal investment decision rules for an energy beet ethanol firm to exercise the option to invest, mothball, reactivate, and exit the ethanol market, considering uncertainty and volatility in the market price of ethanol, feedstock, and irreversible investment. A real options framework is used to compute gross margins of ethanol that trigger entry into and exit from the ethanol market. Results show that volatility in ethanol gross margins has much greater effects on exit and entry decisions than investment costs, and it also causes firms to wait longer before entering the ethanol market and, once active, to wait longer before exiting.

Effect of storage conditions on industrial sugar retention in energy beets

Energy beets could compete with corn grain as important industrial-sugar feedstocks for biofuels. However, long-term energy beet storage is necessary to maximize processing equipment use, and storage conditions may entirely differ from those established in the sugar industry. This work evaluated combined effects of surface treatment, temperature, and storage atmosphere on beet sugar retention. Initially, beets were dipped in solutions of either a senescence inhibitor (N6-benzylaminopurine) or one of two antimicrobial agents (acetic acid and pHresh 10.0r) at weight fractions of 0.05 and 0.1%, and 0.1 and 1%, respectively. Beets were then stored for up to 36 wk either under aerobic conditions or in sealed containers, at 6ºC or 25ºC. Surface treatment did not show a statistically significant effect on sugar retention. Aerobic storage at 25ºC enabled initial beet sugar retention due to dehydration caused by low relative humidity (37%) in air. In contrast, aerobic storage at 6ºC enabled sugar retention for 24 wk; however, sugar retention decreased sharply thereafter to 56%. This decrease coincided with mold appearance on beet surfaces. Beets stored in sealed containers at both temperatures retained 38% of initial sugars. Increasing surface area to better incorporate preservatives into beet tissue could improve long-term sugar retention.

Effect on Different Modes to Ethanol Fermentation of Energy Beet

In order to meet the needs of industrial mass production,people began to explore the effect on different modes to ethanol fermentation.Ethanol fermentation with energy beet was done by using batch fermentation and continuous fermentation.Results showed that batch fermentation was better than continuous mode,but its technology was cockamamie.The residual glucose content in fermenting mash was high when fermentation was continuous.And the fermentation was halfway.But continuous fermentation was convenient for industrialization producing.Although the residual glucose content in continuous fermentation mode was high through 0.06 h-1 sugar concentration,the last translation rate of ethanol was high.

Technological Optimization of Ethanol Fermentation on Energy Beet with Tolerance High Temperature Yeast Strain

Temperature affected ethanol fermentation of energy beet greatly.This study showed that yeast HADY was tolerant to high temperature and when the fermentation temperature was 45°C,the translation rate of ethanol was higher.The three main factors were screened out from nine factors related fermentation by Plackett-Burman design and response surface methodology, such as substrate concentration, ratio of solvent to material, added HADY amount,nutrient salts, phosphorus addition amount, pH value, rotational speed, fermentation temperature and fermentation time. The three main factors included substrate concentration, fermentation temperature and phosphorus addition amount.The optimized technological parameters of HADY were as follows:substrate concentration12%, ratio of solvent to material 1:1, added HADY15%,nutrient salts 0.5,added phosphorus 0.9%, pH 5.0,rotation speed 130r/min, fermentation temperature 37°C and fermentation time 44 hours.At the time, the result showed that the translation rate of ethanol was 89.43%.