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This study analyzes the feasibility of using algae cultivated from wastewater effluent to produce a biodiesel feedstock. The goal was to determine if the energy produced was greater than the operational energy consumed without consideration to constructing the system as well as the emissions and economic value associated with the

This study analyzes the feasibility of using algae cultivated from wastewater effluent to produce a biodiesel feedstock. The goal was to determine if the energy produced was greater than the operational energy consumed without consideration to constructing the system as well as the emissions and economic value associated with the process.

Four scenarios were created:
       1) high-lipid, dry extraction.
       2) high-lipid, wet extraction.
       3) low-lipid, dry extraction.
       4) low-lipid, wet extraction.
In all cases, the system required more energy than it produced. In high lipid scenarios, the energy produced is close to the energy consumed, and a positive net energy balance may be achieved with minor improvements in technology or accounting for coproducts. In the low lipid scenarios, the energy balance is too negative to be considered feasible. Therefore the lipid content affects the decision to implement algae cultivation.

The dry extraction and the wet extraction both require some level of mechanical drying and this makes the two methods yield similar results in terms of the energy analysis. Therefore, the extraction method does not dramatically affect the decision for implementing algae-based oil production from an energetic standpoint. The economic value of the oil in both high lipid scenarios results in a net profit despite the negative net energy. Emission calculations resulted in avoiding a significant amount of CO2 for high lipid scenarios but not for the low lipid scenarios. The CO2 avoided does not account for non-lipid biomass, so this number is an underestimation of the final CO2 avoided from the end products.

While the term "CO2 avoided" has been used for this study, it should be noted that this CO2 would be emitted upon use as a fuel source. These emissions, however, are not “new” CO2 because it has already been emitted and is being captured and recycled. Currently, literature is very divisive on the lipid content present in algae and this study shows that lipid content has a tremendous affect on energy and emissions impacts. The type of algae that can grow in wastewater effluent also should be investigated as well as the conditions that promote high lipid accumulation. The dewatering phase must be improved as it is extremely energy intensive and dominates the operational energy balance.

In order to compete, wet extraction must have a much more significant effect on the drying phase and must avoid the use of the human toxicants methanol and chloroform. Additionally, while the construction phase was beyond the scope of this project it may be a critical aspect in determining the feasibility these systems. Future research in this field should focus on lipid production, optimizing the belt dryer or finding a different method of dewatering, and allocating the coproducts.

Created2012-05
Description
An issue with the utilization of swimming pools is that pumps are operated an excessive number of hours to keep the pool free of debris and algae. Case in point, according to the pool industry, a pump should operate one hour for every ten degrees of ambient temperature. A dynamic

An issue with the utilization of swimming pools is that pumps are operated an excessive number of hours to keep the pool free of debris and algae. Case in point, according to the pool industry, a pump should operate one hour for every ten degrees of ambient temperature. A dynamic model and a control strategy have been developed using Matlab/Simulink that uses environmental conditions together with chemicals that hinder or aid algae growth in order to determine algae population. This model suggests ways to function the pump on shorter time intervals to reduce energy consumption, while simultaneously maintaining algae populations at acceptable levels. Other factors included in the model are pool thermal dynamics and pool pump/filter performance characteristics, since they also have an effect algae growth. This thesis presents the first step for an alternative way of operating a swimming pool by minimizing operating costs while eliminating algae.
ContributorsBallard, Roderick (Author) / Macia, Narciso (Thesis advisor) / Narveson, Brentt (Committee member) / Mchenry, Albert (Committee member) / Dempster, Thomas (Committee member) / Arizona State University (Publisher)
Created2012
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Description
There has been considerable advancement in the algae research field to move algae production for biofuels and bio-products forward to become commercially viable. However, there is one key element that humans cannot control, the natural externalities that impact production. An algae cultivation system is similar to agricultural crop farming practices.

There has been considerable advancement in the algae research field to move algae production for biofuels and bio-products forward to become commercially viable. However, there is one key element that humans cannot control, the natural externalities that impact production. An algae cultivation system is similar to agricultural crop farming practices. Algae are grown on an area of land for a certain time period with the aim of harvesting the biomass produced. One of the advantages of using algae biomass is that it can be used as a source of energy in the form of biofuels. Major advances in algae research and development practices have led to new knowledge about the remarkable potential of algae to serve as a sustainable source of biofuel. The challenge is to make the price of biofuels from algae cost-competitive with the price of petroleum-based fuels. The scope of this research was to design a concept for an automated system to control specific externalities and determine if integrating the system in an algae cultivation system could improve the algae biomass production process. This research required the installation and evaluation of an algae cultivation process, components selection and computer software programming for an automated system. The results from the automated system based on continuous real time monitored variables validated that the developed system contributes insights otherwise not detected from a manual measurement approach. The implications of this research may lead to technology that can be used as a base model to further improve algae cultivation systems.
ContributorsPuruhito, Emil (Author) / Sommerfeld, Milton (Thesis advisor) / Gintz, Jerry (Thesis advisor) / Alford, Eddie (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Sea ice algae dominated by diatoms inhabit the brine channels of the Arctic sea ice and serve as the base of the Arctic marine food web in the spring. I studied sea ice diatoms in the bottom 10 cm of first year land-fast sea ice off the coast of Barrow,

Sea ice algae dominated by diatoms inhabit the brine channels of the Arctic sea ice and serve as the base of the Arctic marine food web in the spring. I studied sea ice diatoms in the bottom 10 cm of first year land-fast sea ice off the coast of Barrow, AK, in spring of 2011, 2012, and 2013. I investigated the variability in the biomass and the community composition of these sea-ice diatoms between bloom phases, as a function of overlying snow depth and over time. The dominant genera were the pennate diatoms Nitzschia, Navicula, Thalassiothrix, and Fragilariopsis with only a minor contribution by centric diatoms. While diatom biomass as estimated by organic carbon changed significantly between early, peak, and declining bloom phases (average of 1.6 mg C L-1, 5.7 mg C L-1, and 1.0 mg C L-1, respectively), the relative ratio of the dominant diatom groups did not change. However, after export, when the diatoms melt out of the ice into the underlying water, diatom biomass dropped by ~73% and the diatom community shifted to one dominated by centric diatoms. I also found that diatom biomass was ~77% lower under high snow cover (>20 cm) compared to low snow cover (<8 cm); however, the ratio of the diatom categories relative to particulate organic carbon (POC) was again unchanged. The diatom biomass was significantly different between the three sampling years (average of 2.4 mg C L-1 in 2011, 1.1 mg C L-1 in 2012, and 5.4 mg C L-1 in 2013, respectively) as was the contribution of all of the dominant genera to POC. I hypothesize the latter to be due to differences in the history of ice sheet formation each year. The temporal variability of these algal communities will influence their availability for pelagic or benthic consumers. Furthermore, in an Arctic that is changing rapidly with earlier sea ice and snowmelt, this time series study will constitute an important baseline for further studies on how the changing Arctic influences the algal community immured in sea ice.
ContributorsKinzler, Kyle (Author) / Neuer, Susanne (Thesis advisor) / Juhl, Andrew (Committee member) / Hartnett, Hilairy (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Microscopic algae have been investigated extensively by researchers for decades for their ability to bioremediate wastewater and flue gas while producing valuable biomass for use as feed, fuel, fertilizer, nutraceutical, and other specialty products. Reports of the exciting commercial potential of this diverse group of organisms started appearing in

Microscopic algae have been investigated extensively by researchers for decades for their ability to bioremediate wastewater and flue gas while producing valuable biomass for use as feed, fuel, fertilizer, nutraceutical, and other specialty products. Reports of the exciting commercial potential of this diverse group of organisms started appearing in the literature as early as the 1940’s. However, nearly 80 years later, relatively few successful commercial microalgae installations exist and algae have not yet reached agricultural commodity status. This dissertation examines three major bottlenecks to commercial microalgae production including lack of an efficient and economical cultivation strategy, poor management of volatile waste nutrients, and costly harvesting and post processing strategies. A chapter is devoted to each of these three areas to gain a better understanding of each bottleneck as well as strategies for overcoming them.

The first chapter demonstrates the capability of two strains of Scenedesmus acutus to grow in ultra-high-density (>10 g L-1 dry weight biomass) cultures in flat panel photobioreactors for year-round production in the desert Southwest with record volumetric biomass productivity. The advantages and efficiency of high-density cultivation are discussed. The second chapter focuses on uptake and utilization of the volatile components of wastewater: ammonia and carbon dioxide. Scenedesmus acutus was cultured on wastewater from both municipal and agricultural origin and was shown to perform significantly better on flue gas as compared to commercial grade CO2 and just as well on waste nutrients as the commonly used BG-11 laboratory culture media, all while producing up to 50% lipids of the dry weight biomass suitable for use in biodiesel. The third chapter evaluates the feasibility of using gravity sedimentation for the harvesting of the difficult-to-separate Scenedesmus acutus green algae biomass followed by microfluidization to disrupt the cells. Lipid-extracted biomass was then studied as a fertilizer for plants and shown to have similar performance to a commercially available 4-6-6 fertilizer. Based on the work from these three chapters, a summary of modifications are suggested to help current and future microalgae companies be more competitive in the marketplace with traditional agricultural commodities.
ContributorsWray, Joshua (Author) / Dempster, Thomas (Thesis advisor) / Roberson, Robert (Thesis advisor) / Bingham, Scott (Committee member) / Neuer, Susanne (Committee member) / Arizona State University (Publisher)
Created2019
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Description
Hydrothermal Liquefaction of Algae represents one of many pathways for the sustainable replacement of fossil fuels in transportation. When processing and researching algal biofuel, determination of the higher heating value (HHV) is paramount. Bomb calorimetry represents to current method for direct determination of HHV. When determining HHV’s indirectly, the industry

Hydrothermal Liquefaction of Algae represents one of many pathways for the sustainable replacement of fossil fuels in transportation. When processing and researching algal biofuel, determination of the higher heating value (HHV) is paramount. Bomb calorimetry represents to current method for direct determination of HHV. When determining HHV’s indirectly, the industry standard is using one of many linear correlations relating elemental composition to HHV. Most of these correlations were developed from coal industry data, meaning that they do not necessarily fit algal product data well. In this study bomb calorimetry data and CHNS/O elemental composition data were collected for Chlorella, Micract, GS 5587.1, Kirchnella, and Gal 87.1 MM8 algae species. This data was added to CHNS/O and HHV values for other algal products in literature, and utilized to test the accuracy of the Dulong, Gumz, Vandralek and Boie correlations for algae products. Several preliminary algae specific correlations were proposed through a linear regression model of the data. Of the 5 samples tested, Kirchnella exhibited the highest HHV (23.2405 ± 0.0216 MJ/kg) and Chlorella exhibited the lowest (20.2055 ± 0.0484 MJ/kg). For both the experimental, and literature CHNS/O vs HHV data, the Vandralek and Boie correlations provided the best approximations in this study. For the totality of the data collected and researched in this study, 6 of 8 proposed correlations outperformed the Vandralek equation for HHV approximation. The most promising proposed correlations incorporated multiple linear regressions for elemental fractions of CHS, CHSO and CHNSO. Being that only 20 distinct algal product samples were regressed to create the proposed correlations, more data should be incorporated before publication of a final correlation. This study should serve as a starting point for the compilation of an exhaustive database for algal product assay and HHV data.
ContributorsCopp, Connor Joseph (Author) / Deng, Shuguang (Thesis director) / Muppaneni, Tapaswy (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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Description
To date, the production of algal biofuels is not economically sustainable due to the cost of production and the low cost of conventional fuels. As a result, interest has been shifting to high value products in the algae community to make up for the low economic potential of algal biofuels.

To date, the production of algal biofuels is not economically sustainable due to the cost of production and the low cost of conventional fuels. As a result, interest has been shifting to high value products in the algae community to make up for the low economic potential of algal biofuels. The economic potential of high-value products does not however, eliminate the need to consider the environmental impacts. The majority of the environmental impacts associated with algal biofuels overlap with algal bioproducts in general (high-energy dewatering) due to the similarities in their production pathways. Selecting appropriate product sets is a critical step in the commercialization of algal biorefineries.

This thesis evaluates the potential of algae multiproduct biorefineries for the production of fuel and high-value products to be economically self-sufficient and still contribute to climate change mandates laid out by the government via the Energy Independence and Security Act (EISA) of 2007. This research demonstrates:

1) The environmental impacts of algal omega-3 fatty acid production can be lower than conventional omega-3 fatty acid production, depending on the dewatering strategy.

2) The production of high-value products can support biofuels with both products being sold at prices comparable to 2016 prices.

3) There is a tradeoff between revenue and fuel production

4) There is a tradeoff between the net energy ratio of the algal biorefinery and the economic viability due to the lower fuel production in a multi-product model that produces high-value products and diesel vs. the lower economic potential from a multi-product model that just produces diesel.

This work represents the first efforts to use life cycle assessment and techno-economic analysis to assess the economic and environmental sustainability of an existing pilot-scale biorefinery tasked with the production of high-value products and biofuels. This thesis also identifies improvements for multiproduct algal biorefineries that will achieve environmentally sustainable biofuel and products while maintaining economic viability.
ContributorsBarr, William James (Author) / Landis, Amy E. (Thesis advisor) / Westerhoff, Paul (Thesis advisor) / Rittmann, Bruce (Committee member) / Khanna, Vikas (Committee member) / Arizona State University (Publisher)
Created2016
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Description
This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a

This thesis examines the use of the moisture swing resin materials employed at the Center for Negative Carbon Emissions (CNCE) in order to provide carbon dioxide from ambient air to photobioreactors containing extremophile cyanobacteria cultured at the Arizona Center for Algae Technology and Innovation (AzCATI). For this purpose, a carbon dioxide feeding device was designed, built, and tested. The results indicate how much resin should be used with a given volume of algae medium: approximately 500 grams of resin can feed 1% CO2 at about three liters per minute to a ten liter medium of the Galdieria sulphuraria 5587.1 strain for one hour (equivalent to about 0.1 grams of carbon dioxide per hour per seven grams of algae). Using the resin device, the algae grew within their normal growth range: 0.096 grams of ash-free dry weight per liter over a six hour period. Future applications in which the resin-to-algae process can be utilized are discussed.
ContributorsBeaubien, Courtney (Author) / Lackner, Klaus (Thesis advisor) / Lammers, Peter (Committee member) / Atkins, Steve (Committee member) / Arizona State University (Publisher)
Created2016
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Description
The project aims at utilization of hydrothermal liquefaction (HTL) byproducts like biochar to grow microalgae. HTL is a promising method to convert wet algal biomasses into biofuels. The initial microalgae liquefaction at a temperature of 300 °C for 30 minute, converted 31.22 % of the Galdieria sulphuraria and 41.00 %

The project aims at utilization of hydrothermal liquefaction (HTL) byproducts like biochar to grow microalgae. HTL is a promising method to convert wet algal biomasses into biofuels. The initial microalgae liquefaction at a temperature of 300 °C for 30 minute, converted 31.22 % of the Galdieria sulphuraria and 41.00 % of the Kirchneriella cornutum into biocrude. Upon changing the reactor from a 100 ml to a 250 ml reactor, the yield in biocrude increased to 31.48 % for G. sulphuraria and dropped to 38.05 % for K. cornutum. Further, energy recoveries based on calorific values of HTL products were seen to drop by about 5 % of the 100 ml calculated values in the larger reactor.

Biochar from HTL of G. sulphuraria at 300 °C showed 15.98 and 5.27 % of phosphorous and nitrogen, respectively. HTL products from the biomass were analyzed for major elements through ICP-OES and CHNS/O. N and P are macronutrients that can be utilized in growing microalgae. This could reduce the operational demands in growing algae like, phosphorous mined to meet annual national demand for aviation fuel. Acidic leaching of these elements as phosphates and ammoniacal nitrogen was studied. Improved leaching of 49.49 % phosphorous and 95.71 % nitrogen was observed at 40 °C and pH 2.5 over a period of 7 days into the growth media. These conditions being ideal for growth of G. sulphuraria, leaching can be done in-situ to reduce overhead cost.

Growth potential of G. sulphuraria in leached media was compared to a standard cyanidium media produced from inorganic chemicals. Initial inhibition studies were done in the leached media at 40 °C and 2-3 vol. % CO2 to observe a positive growth rate of 0.273 g L-1 day-1. Further, growth was compared to standard media with similar composition in a 96 well plate 50 μL microplate assay for 5 days. The growth rates in both media were comparable. Additionally, growth was confirmed in a 240 times larger tubular reactor in a Tissue Culture Roller drum apparatus. A better growth was observed in the leached cyanidium media as compared to the standard variant.
ContributorsMathew, Melvin (Author) / Deng, Shuguang (Thesis advisor) / Lammers, Peter J. (Committee member) / Nielsen, David R (Committee member) / Arizona State University (Publisher)
Created2017
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Description

Temperature swing adsorption is a commonly used gas separation technique, and is being<br/>further researched as a method of carbon capture. Carbon capture is becoming increasingly<br/>important as a potential way to slow global warming. In this study, algae-derived activated<br/>carbon adsorbents were analyzed for their carbon dioxide adsorption effectiveness.<br/>Algae-derived carbon adsorbents were

Temperature swing adsorption is a commonly used gas separation technique, and is being<br/>further researched as a method of carbon capture. Carbon capture is becoming increasingly<br/>important as a potential way to slow global warming. In this study, algae-derived activated<br/>carbon adsorbents were analyzed for their carbon dioxide adsorption effectiveness.<br/>Algae-derived carbon adsorbents were synthesized and then studied for their adsorption<br/>isotherms and adsorption breakthrough behavior. From the generated isotherm plots, it was<br/>determined that the carbonization temperature was not high enough and that more batches of<br/>adsorbent would have to be made to more accurately analyze the adsorptive potential of the<br/>algae-derived carbon adsorbent.

ContributorsCiha, Trevor (Author) / Deng, Shuguang (Thesis director) / Taylor, David (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05