Browsing by Subject "biofuel"
Now showing 1 - 8 of 8
- Results Per Page
- Sort Options
Item Algal biofuels : the effect of salinity and pH on growth and lipid content of algae(2009-08) Gutierrez, Cesar Carlos; Marshall, Jill Ann; Sathasivan, Kanagasabapathi; Mehdy, Mona Cynthia, 1955-Supplies of nonrenewable fossil fuels are becoming more limited even as they continue to contribute to pollution and economic concerns. Alternative sources of energy must be developed that help minimize these problems. One potential source of energy is the production of biofuels from algae. Here we evaluate algae found in South Texas brackish water ponds used for aquaculture of fish as a possible source of biofuels. In particular, we examine the effects of salinity and pH on the growth and lipid content of the algae. Samples of algae from the ponds exhibited high levels of growth and lipid production at a salinity of 9 ppt and pH 7. These conditions are similar to the natural conditions of the ponds, indicating that they may be a good source of algal biofuels.Item Biofuel: An Ethical Burnout(2016-11-18) Henry, ConradItem Comprehensive evaluation of algal biofuel production: Experimental and target results(MDPI, 2012-06-20) Beal, Colin M.; Hebner, Robert E.; Webber, Michael E.; Ruoff, Rodney S.; Seibert, A. Frank; King, Carey W.; Beal, Colin M.; Hebner, Robert E.; Webber, Michael E.; Ruoff, Rodney S.; Seibert, A. Frank; King, Carey W.Worldwide, algal biofuel research and development efforts have focused on increasing the competitiveness of algal biofuels by increasing the energy and financial return on investments, reducing water intensity and resource requirements, and increasing algal productivity. In this study, analyses are presented in each of these areas—costs, resource needs, and productivity—for two cases: (1) an Experimental Case, using mostly measured data for a lab-scale system, and (2) a theorized Highly Productive Case that represents an optimized commercial-scale production system, albeit one that relies on full-price water, nutrients, and carbon dioxide. For both cases, the analysis described herein concludes that the energy and financial return on investments are less than 1, the water intensity is greater than that for conventional fuels, and the amounts of required resources at a meaningful scale of production amount to significant fractions of current consumption (e.g., nitrogen). The analysis and presentation of results highlight critical areas for advancement and innovation that must occur for sustainable and profitable algal biofuel production can occur at a scale that yields significant petroleum displacement. To this end, targets for energy consumption, production cost, water consumption, and nutrient consumption are presented that would promote sustainable algal biofuel production. Furthermore, this work demonstrates a procedure and method by which subsequent advances in technology and biotechnology can be framed to track progress.Item Comprehensive Evaluation of Algal Biofuel Production: Experimental and Target Results(MDPI, 2012-06) Beal, C.M.; Hebner, R.E.; Webber, M.E.; Ruoff, R.S.; Seibert, A.F.; King, C.W.Worldwide, algal biofuel research and development efforts have focused on increasing the competitiveness of algal biofuels by increasing the energy and financial return on investments, reducing water intensity and resource requirements, and increasing algal productivity. In this study, analyses are presented in each of these areas—costs, resource needs, and productivity—for two cases: (1) an Experimental Case, using mostly measured data for a lab-scale system, and (2) a theorized Highly Productive Case that represents an optimized commercial-scale production system, albeit one that relies on full-price water, nutrients, and carbon dioxide. For both cases, the analysis described herein concludes that the energy and financial return on investments are less than 1, the water intensity is greater than that for conventional fuels, and the amounts of required resources at a meaningful scale of production amount to significant fractions of current consumption (e.g., nitrogen). The analysis and presentation of results highlight critical areas for advancement and innovation that must occur for sustainable and profitable algal biofuel production can occur at a scale that yields significant petroleum displacement. To this end, targets for energy consumption, production cost, water consumption, and nutrient consumption are presented that would promote sustainable algal biofuel production. Furthermore, this work demonstrates a procedure and method by which subsequent advances in technology and biotechnology can be framed to track progress.Item Energy return on investment for algal biofuel production coupled with wastewater treatment(Water Environment Research, 2012) Beal, Colin M.; Stillwell, Ashlynn S.; King, Carey W.; Cohen, Stuart M.; Berberoglu, Halil; Bhattarai, Rajendra P.; Connelly, Rhykka L.; Webber, Michael E.; Hebner, Robert E.; Beal, Colin M.; Stillwell, Ashlynn S.; King, Carey W.; Cohen, Stuart M.; Berberoglu, Halil; Bhattarai, Rajendra P.; Connelly, Rhykka L.; Webber, Michael E.; Hebner, Robert E.This study presents a second-order energy return on investment analysis to evaluate the mutual benefits of combining an advanced wastewater treatment plant (WWTP) (with biological nutrient removal) with algal biofuel production. With conventional, independently operated systems, algae production requires significant material inputs, which require energy directly and indirectly, and the WWTP requires significant energy inputs for treatment of the waste streams. The second-order energy return on investment values for independent operation of the WWTP and the algal biofuels production facility were determined to be 0.37 and 0.42, respectively. By combining the two, energy inputs can be reduced significantly. Consequently, the integrated system can outperform the isolated system, yielding a second-order energy return on investment of 1.44. Combining these systems transforms two energy sinks to a collective (second-order) energy source. However, these results do not include capital, labor, and other required expenses, suggesting that profitable deployment will be challenging.Item Progression of lipid profile and cell structure in a research-scale production pathway for algal biocrude(Elsevier, 2013-02) Beal, C.M.; Hebner, R.E.; Romanovicz, D.K.; Mayer, C.C.; Connelly, R.L.Although there has been a large research effort associated with individual parts of various algal biofuel production pathways, few studies have tracked changes in product composition throughout an integrated biofuel production process. This study uses microscopy and chromatography to analyze the progression of lipid profile and cell structure of algal cells throughout a research-scale production pathway for biocrude. For the specific processing methods used in this pathway, it is shown that TAG content decreased, while DAG and FFA content increased during processing. The changes in the lipid content corresponded to cell degradation that was observed by SEM and TEM throughout processing. These results demonstrate the dynamic nature of lipid composition in an algal culture used for biofuel production and emphasize the need to monitor changes in lipid profile, as those changes can directly impact biofuel productivity.Item Thermodynamic analysis of algal biocrude production(Elsevier, 2012-08) Beal, C.M.; Hebner, R.E.; Webber, M.E.Although algal biofuels possess great potential, profitable production is quite challenging. Much of this challenge is rooted in the thermodynamic constraints associated with producing fuels with high energy, low entropy, and high exergy from dispersed materials. In this study, a preliminary thermodynamic analysis is presented that calculates the energy, entropy, and exergy of the intermediate products for algal biocrude production. These values are also used in an initial attempt to characterize the thermodynamic efficiency of that system. The production pathway is simplified by assuming ideal solutions throughout. Results for the energy and exergy efficiencies, and the first-order energy and exergy return on investment, of the system are given. The summary finding is that the first-order energy return on investment in the best case considered could be as high as 520, as compared to 1.7 × 10?3 in the experimental unit under development. While this analysis shows that significant improvement may be possible, the ultimate thermodynamic efficiency of algal biofuels likely lies closer to the moderate case examined here, which yielded a first-order energy return on investment of 10. For perspective, the first-order energy return on investment for oil and gas production has been estimated in the literature to be ?35.Item Use of Anion Exchange Resins for One-Step Processing of Algae from Harvest to Biofuel(MDPI, 2012-07) Jones, J.; Lee, C-H.; Wang, J.; Poenie, M.Some microalgae are particularly attractive as a renewable feedstock for biodiesel production due to their rapid growth, high content of triacylglycerols, and ability to be grown on non-arable land. Unfortunately, obtaining oil from algae is currently cost prohibitive in part due to the need to pump and process large volumes of dilute algal suspensions. In an effort to circumvent this problem, we have explored the use of anion exchange resins for simplifying the processing of algae to biofuel. Anion exchange resins can bind and accumulate the algal cells out of suspension to form a dewatered concentrate. Treatment of the resin-bound algae with sulfuric acid/methanol elutes the algae and regenerates the resin while converting algal lipids to biodiesel. Hydrophobic polymers can remove biodiesel from the sulfuric acid/methanol, allowing the transesterification reagent to be reused. We show that in situ transesterification of algal lipids can efficiently convert algal lipids to fatty acid methyl esters while allowing the resin and transesterification reagent to be recycled numerous times without loss of effectiveness.