Showing papers on "Algae fuel published in 2016"

Macroalgae and microalgae as a potential source for commercial applications along with biofuels production: A biorefinery approach

Abstract: Due to diminishing petroleum reserves and deleterious environmental consequences of exhaust gases from fossil-based fuels, research on renewable and environment friendly fuels has received a lot of impetus in the recent years. However, the availability of the non-edible crops serve as the sources for biofuel production are limited and economically not feasible. Algae are a promising alternative source to the conventional feedstocks for the third generation biofuel production. There has been a considerable discussion in the recent years about the potential of microalgae for the production of biofuels, but there may be other more readily exploitable commercial opportunities for macroalgae and microalgae. This review, briefly describes the biofuels conversion technologies for both macroalgae and microalgae. The gasification process produces combustible gases such as H2, CH4, CO2 and ammonia, whereas, the product of pyrolysis is bio-oil. The fermentation product of algae is ethanol, that can be used as a direct fuel or as a gasohol. Hydrogen can be obtained from the photobiological process of algal biomass. In transesterification process, algae oil is converted into biodiesel, which is quite similar to those of conventional diesel and it can be blended with the petroleum diesel. This study, also reviewed the production of high value byproducts from macroalgae and microalgae and their commercial applications. Algae as a potential renewable resource is not only used for biofuels but also for human health, animal and aquatic nutrition, environmental applications such as CO2 mitigation, wastewater treatment, biofertilizer, high-value compounds, synthesis of pigments and stable isotope biochemicals. This review is mainly an attempt, to investigate the biorefinery concept applied on the algal technology, for the synthesis of novel bioproducts to improve the algal biofuels as even more diversified and economically competitive. The employment of a high-value, co-product strategy through the integrated biorefinery approach is expected to significantly enhance the overall commercial implementation of the biofuel from the algal technology.

Use of Microalgae for Advanced Wastewater Treatment and Sustainable Bioenergy Generation

Abstract: Given that sustainable energy production and advanced wastewater treatment for producing clean water are two major challenges faced by modern society, microalgae make a desirable treatment alternative by providing a renewable biomass feedstock for biofuel production, while treating wastewater as a growth medium. Microalgae have been known to be resilient to the toxic contaminants of highly concentrated organic wastewater (e.g., organic nitrogen, phosphorus, and salinity) and are excellent at sorbing heavy metals and emerging contaminants. Economic and environmental advantages associated with massive algae culturing in wastewater constitute a driving force to promote its utilization as a feedstock for biofuels. However, there are still many challenges to be resolved which have impeded the development of algal biofuel technology at a commercial scale. This review provides an overview of an integrated approach using microalgae for wastewater treatment, CO2 utilization, and biofuel production. The ma...

Microalgae biofuels: A comparative study on techno-economic analysis & life-cycle assessment

Abstract: This work analyses the sustainability of microalgae-derived biofuel production by performing an extensive comparison of conversion pathways, one studied at the University of Aveiro (UA), Portugal and the other studied at the National Renewable Energy Laboratory (NREL), Golden, Colorado, USA. The objective of this comparison is to address each of these processing technologies from beginning to end by way of a life-cycle assessment and an economic feasibility analysis aimed at large-scale application. An integrated algal biofuel production model was established through the development of separate data inventories supporting both the UA and NREL scenarios. Among the processing technologies evaluated were solvent extraction, trans-esterification and product purification for biodiesel (UA), fermentation, distillation, and hydrodeoxygenation for renewable diesel (NREL). The computed minimum fuel selling prices (in 2011-year dollars) were $10.55/GGE (gasoline gallon equivalent) and $4.35/GGE for the UA-Portugal pathway and the NREL-USA case, respectively. The work shows that the valorization of co-products is particularly significant since it adds revenue which may be used to improve the final fuel selling price. Analysis of the NREL pathway shows that the algae biomass cultivation step contributes significantly (~ 50%) to total emissions, which emphasizes the decisive role the ‘microalgae growth phase’ plays in such a process. The life-cycle analysis, conducted with SimaPro software, shows that the biofuel processing technology adopted by UA, albeit simpler, requires upgrading in order to achieve optimum results: the lipid extraction process is extremely problematic because it contributes significantly to greenhouse gas (GHG) emissions and fossil energy consumption. Increasing the recovery of solvent (hexane) used during the process can play a major role in reducing total GHG emissions.

Macroalgae (seaweed) for liquid transportation biofuel production: what is next?

Abstract: Marine algal biofuel is considered a promising solution for energy and environmental challenges. Macroalgal biomass has the potential for bypassing the shortcoming of first and second generation of biomass from food crop and lignocellulosic sources. In this review, we summarize the findings in this domain in the past two decades with a focus on the process of saccharification and fermentation of macroalgae for transportation biofuels. In general, macroalgae contains high levels of carbohydrates, almost no or comparatively less lignin than in terrestrial plants, which makes it a very promising source for liquid biofuel production via bioconversion. After harvest, macroalgal biomass goes through several process units, including pre-treatment and/or saccharification and fermentation to be converted to biofuel, e.g., bioethanol. We also propose strategies for further studies to realize macroalgae biomass potential for transportation bioenergy production.

Characteristics analysis of carbon nanowires in diesel: Neochloris oleoabundans algae oil biodiesel–ethanol blends in a CI engine

Abstract: The present work is dedicated to the study of diesel–biodiesel–ethanol blends in a diesel engine using carbon nanowires additives of various concentrations. Algae oil from microalgae has the possibility of becoming a sustainable fuel source as biodiesel. The Neochloris oleoabundans algal oil was extracted by the mechanical extraction method. The transesterification reaction of algal oil with methanol and base catalyst was used for the production of biodiesel. Experimental investigation results were studied for various parameters such as exhaust emission of carbon monoxide, hydrocarbon, oxides of nitrogen gases, and smoke.

Microalgae Potential and Multiple Roles—Current Progress and Future Prospects—An Overview

Abstract: Substantial progress has been made in algal technologies in past few decades. Initially, microalgae drew the attention of the scientific community as a renewable source of biofuels due to its high productivity over a short period of time and potential of significant lipid accumulation. As of now, a technological upsurge has elaborated its scope in phycoremediation of both organic and inorganic pollutants. The dual role of microalgae—i.e., phycoremediation coupled with energy production—is well established, however, commercially, algal biofuel production is not yet sustainable due to high energy inputs. Efforts are being made to make the algal biofuel economy through modification in the cultivation conditions, harvesting, and extraction of value added products. Recent studies have demonstrated algal biomass production with various types of wastewater and industrial effluents. Similarly, the recent advent of eco-friendly harvesting technologies—such as low-cost green coagulants, electrochemical harvesting, etc.—are energy efficient and economical. Contemporary improvement in efficient lipid extraction from biomass will make algal biodiesel economical. The absolute extraction of all the value added products from algal biomass, either whole cell or lipid extracted biomass, in a complete biorefinery approach will be more economical and eco-friendly.

Environmental impact of an algal biofuel doped with carbon black

Abstract: This paper investigated the role of the emission characteristics of a diesel engine when carbon black (CB) blended with Caulerpa peltata algae oil methyl ester (CPOME) is used as a fuel. Biodiesels are produced from Caulerpa peltata algae oil (CPO) by the transesterification process. The biodiesel blends containing 10%, 15%, and 20% CB were denoted as B20, B20CB10, B20CB15, and B20CB20. The CPOME was mixed with CB nanoparticles with the aid of a mechanical stirrer. The fuel properties of all blends were studied and compared according to ASTM standard. Tests were performed at full-load CI engine operation with a constant speed of 1500 rpm. The acquired data were studied for various parameters, such as exhaust emissions of HC, CO, CO2, NOx, and smoke opacity.

Emission analysis of the effect of carbon nanowires in biodiesel–ethanol blends

Abstract: The present work is dedicated to study of diesel–biodiesel–ethanol blends in a diesel engine using addition of various concentrations of carbon nanowires. Algae oil from microalgae has the potential to become a sustainable fuel source as biodiesel. The Neochloris oleoabundans algal oil was extracted by mechanical extraction method. The transesterification reaction of algal oil with methanol and base catalyst was used for the production of biodiesel. Experimental investigation results were studied for various parameters, such as exhaust emission of carbon monoxide, hydrocarbon, oxides of nitrogen gases, smoke, and carbon dioxide.

From macroalgae to liquid fuel via waste-water remediation, hydrothermal upgrading, carbon dioxide hydrogenation and hydrotreating

Abstract: This article showcases a proof-of-concept in the production of high quality renewable biofuel from algae. Here, we introduce a path combining a number of approaches that, when integrated as a whole, create a process that takes algae grown in waste-water through to a liquid fuel containing fractions ready for blending with regular gasoline, jet fuel and diesel. With the overarching goal of reducing the nitrogen content invariably associated with whole algal biomass, we apply a number of approaches including (i) nutrient starvation to reduce the internal nitrogen of the freshwater alga Oedogonium (ii) continuous co-solvent (10 wt% n-heptane) hydrothermal liquefaction (HTL) to produce a non-polar biocrude containing <1 wt% N; (iii) blending the biocrude with green feed produced from the hydrogenation of CO2 to obtain <0.5 wt% N; (iv) hydrogenation and hydro-isomerization of the blend in two stages over nanodisperse silica-supported Ni2P (achieving 630 ppm N) and acidic zeolite-supported Pt catalysts respectively to produce a synthetic paraffinic mixture (SPM) containing 277 ppm N and 0.12% O. With the incorporation of renewable H2 (which can be from gasification of polar organics produced in the solvent HTL, or other renewable sources) and captured CO2 the process demonstrates a new and technically cohesive approach to the production of renewable, high-quality biofuels for demanding transport applications.

Green biodiesel production: a review on feedstock, catalyst, monolithic reactor, and supercritical fluid technology

Abstract: The advancement of alternative energy is primarily catalyzed by the negative environmental impacts and energy depletion caused by the excessive usage of fossil fuels. Biodiesel has emerged as a promising substitute to petrodiesel because it is biodegradable, less toxic, and reduces greenhouse gas emission. Apart from that, biodiesel can be used as blending component or direct replacements for diesel fuel in automotive engines. A diverse range of methods have been reported for the conversion of renewable feedstocks (vegetable oil or animal fat) into biodiesel with transesterification being the most preferred method. Nevertheless, the cost of producing biodiesel is higher compared to fossil fuel, thus impeding its commercialization potentials. The limited source of reliable feedstock and the underdeveloped biodiesel production route have prevented the full-scale commercialization of biodiesel in many parts of the world. In a recent development, a new technology that incorporates monoliths as support matrices for enzyme immobilization in supercritical carbon dioxide (SC-CO2) for continuous biodiesel production has been proposed to solve the problem. The potential of SC-CO2 system to be applied in enzymatic reactors is not well documented and hence the purpose of this review is to highlight the previous studies conducted as well as the future direction of this technology.

Cofactor symbiosis for enhanced algal growth, biofuel production, and wastewater treatment

Abstract: Algae have gained attention for production of fuels and chemicals, and treatment of wastewater. The high cost of algae cultivation, however, has limited industry adoption for these applications. Developing methods to increase algal growth rates and lipid content has emerged as an important strategy toward reducing production costs, and significant research effort has been exerted in this area. We have reported previously that co-culturing the green alga, Auxenochlorella protothecoides, with Escherichia coli under mixotrophic conditions led to 2–6 fold increases in algal growth, doubling of neutral lipid content, and elevated nutrient removal rates compared to axenic growth, indicative of a symbiotic relationship. In the present work, we reveal that symbiosis stems largely from E. coli's provision of thiamine derivatives and degradation products to A. protothecoides. LCMS showed that residual cell-free medium obtained from axenic E. coli culture contained roughly 1.15 nM thiamine pyrophosphate and 4.0–9.1 nM of the thiamine precursor and degradation product, 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP). These compounds were found to promote the growth, lipid content, and glucose uptake of A. protothecoides, while dramatically improving substrate utilization efficiency. Due to widespread cofactor auxotrophy among algae, the co-culture results presented here likely extend to a large number of microbial community systems. We show that algal-algal symbiosis based on cofactor exchange is also possible, opening a new frontier in algae cultivation management. These findings highlight the potential of engineered microbial communities for improved algal biofuel production and wastewater treatment.

A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock.

Abstract: Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

Phytosterol structured algae oil nanoemulsions and powders: improving antioxidant and flavor properties

Abstract: Algae oil, enriched with omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFA), is known for its health benefits. However, protection against lipid oxidation as well as masking of unpleasant fishy malodors in algae oil enriched foods is a big challenge to achieve. In this study, we firstly achieved a one-pot ultrasound emulsification strategy (alternative heating-homogenization) to prepare phytosterol structured thermosensitive algae oil-in-water nanoemulsion stabilized by quillaja saponin. After spray drying, the resulting algae oil powders from the structured nanoemulsion templates exhibit an excellent reconstructed behavior, even after 30 d of storage. Furthermore, an enhanced oxidative stability was obtained by reducing both the primary and secondary oxidation products through formulation with β-sitosterol and γ-oryzanol, which are natural antioxidants. Following the results of headspace volatiles using dynamic headspace-gas chromatography-mass spectrometry (DHS-GC-MS), it was clear that the structured algae oil-loaded nanoemulsion and powder had lower levels of fishy off-flavour (e.g., (Z)-heptenal, decanal, ethanone, and hexadecenoic acid), whereas the control emulsion and oil powder without structure performed worse. This study demonstrated that the structure from phytosterols is an effective strategy to minimize the fishy off-flavour and maximize oxidative stability of both algae oil nanoemulsions and spray-dried powders, and opens up the possibility of formulation design in polyunsaturated oil encapsulates as novel delivery systems to apply in functional foods and beverages.

Target Cultivation and Financing Parameters for Sustainable Production of Fuel and Feed from Microalgae

Abstract: Production of economically competitive and environmentally sustainable algal biofuel faces technical challenges that are subject to high uncertainties. Here we identify target values for algal productivity and financing conditions required to achieve a biocrude selling price of $5 per gallon and beneficial environmental impacts. A modeling framework—combining process design, techno-economic analysis, life cycle assessment, and uncertainty analysis—was applied to two conversion pathways: (1) “fuel only (HTL)”, using hydrothermal liquefaction to produce biocrude, heat and power, and (2) “fuel and feed”, using wet extraction to produce biocrude and lipid-extracted algae, which can substitute components of animal and aqua feeds. Our results suggest that with supporting policy incentives, the “fuel and feed” scenario will likely achieve a biocrude selling price of less than $5 per gallon at a productivity of 39 g/m2/day, versus 47 g/m2/day for the “fuel only (HTL)” scenario. Furthermore, if lipid-extracted alg...

Theoretical Calculations on the Feasibility of Microalgal Biofuels: Utilization of Marine Resources Could Help Realizing the Potential of Microalgae.

Abstract: Microalgae have long been considered as one of most promising feedstocks with better characteristics for biofuels production over conventional energy crops There have been a wide range of estimations on the feasibility of microalgal biofuels based on various productivity assumptions and data from different scales The theoretical maximum algal biofuel productivity, however, can be calculated by the amount of solar irradiance and photosynthetic efficiency (PE), assuming other conditions are within the optimal range Using the actual surface solar irradiance data around the world and PE of algal culture systems, maximum algal biomass and biofuel productivities were calculated, and feasibility of algal biofuel were assessed with the estimation The results revealed that biofuel production would not easily meet the economic break-even point and may not be sustainable at a large-scale with the current algal biotechnology Substantial reductions in the production cost, improvements in lipid productivity, recycling of resources, and utilization of non-conventional resources will be necessary for feasible mass production of algal biofuel Among the emerging technologies, cultivation of microalgae in the ocean shows great potentials to meet the resource requirements and economic feasibility in algal biofuel production by utilizing various marine resources

An experimental study on usage of plastic oil and B20 algae biodiesel blend as substitute fuel to diesel engine.

Abstract: Usage of plastics has been ever increasing and now poses a tremendous threat to the environment. Millions of tons of plastics are produced annually worldwide, and the waste products have become a common feature at overflowing bins and landfills. The process of converting waste plastic into value-added fuels finds a feasible solution for recycling of plastics. Thus, two universal problems such as problems of waste plastic management and problems of fuel shortage are being tackled simultaneously. Converting waste plastics into fuel holds great promise for both the environmental and economic scenarios. In order to carry out the study on plastic wastes, the pyrolysis process was used. Pyrolysis runs without oxygen and in high temperature of about 250–300 °C. The fuel obtained from plastics is blended with B20 algae oil, which is a biodiesel obtained from microalgae. For conducting the various experiments, a 10-HP single-cylinder four-stroke direct-injection water-cooled diesel engine is employed. The engine is made to run at 1500 rpm and the load is varied gradually from 0 to 100 %. The performance, emission and combustion characteristics are observed. The BTE was observed to be higher with respect to diesel for plastic-biodiesel blend and biodiesel blend by 15.7 and 12.9 %, respectively, at full load. For plastic-biodiesel blend, the emission of UBHC and CO decreases with a slight increase in NO x as compared to diesel. It reveals that fuel properties are comparable with petroleum products. Also, the process of converting plastic waste to fuel has now turned the problems into an opportunity to make wealth from waste.

Identification and quantification of suspended algae and bacteria populations using flow cytometry: applications for algae biofuel and biochemical growth systems

Abstract: Species diversity in algae biofuel and biochemical culturing systems can affect yield; in many large-scale algae growth systems, it is not practical to maintain a monoculture. To better understand and monitor these complex systems, techniques are required which can quickly and effectively quantify the species distribution and overall growth of a mixed microbial community in suspension. A flow cytometric method has been developed which can be used to differentiate populations of three Chlorophyta species, one diatom species, cyanobacteria, and heterotrophic bacteria according to their fluorescence and morphology. The nucleic acid stain SYTO9 was used to discriminate species with similar natural autofluorescence and to identify heterotrophic bacteria. Absolute cell enumeration was performed with counting beads and validated with a hemocytometer. Species identification was validated by analyzing known mixtures of axenic cell cultures. The utility of the method was demonstrated by studying the effect of light intensity on species succession, growth, and biomass accumulation in small algae growth systems over 22 days. Flow cytometric analysis, augmented with SYTO9 stain and counting beads, can be utilized to monitor algae biofuel and biochemical growth systems involving multiple species. This method allows for monitoring of contamination, succession, and overall growth in both natural and intentionally created microbial communities.

The Selective Use of Hypochlorite to Prevent Pond Crashes for Algae-Biofuel Production.

Abstract: Although algae-biofuels have many advantages including high areal productivity, algae can be preyed upon by amoebas, protozoans, ciliates, and rotifers, particularly in open pond systems. Thus, these higher organisms need to be controlled. In this study, Chlorella kessleri was used as the algal culture and Brachionus calyciflorus as the source of predation. The effect of sodium hypochlorite (bleach) was tested with the goal of totally inhibiting the rotifer while causing minor inhibition to the alga. The 24-hr LC(50) for B. calyciflorus in spring water was 0.198 mg Cl/L while the 24-hr LC(50) for C. kessleri was 0.321 mg Cl/L. However, chlorine dissipates rapidly as the algae serves as reductant. Results showed a chlorine dosage between 0.45 to 0.6 mg Cl/L and a dosing interval of two hours created the necessary chlorine concentrations to inhibit predation while letting the algae grow; thus giving algae farmers a tool to prevent pond crashes.

Optimal Design of Distributed Algae-Based Biorefineries Using CO2 Emissions from Multiple Industrial Plants

Abstract: This work proposes an optimization approach for capturing carbon dioxide from different industrial facilities to yield an algae-based biorefinery. The proposed approach is based on a distributed system to account for the economies of scale and includes site selection for the processing facilities. Additionally, the model considers optimization for the technologies used in the process stages and different technologies to yield several products. The algae oil that is obtained from each facility can be sent to processing hubs located in the same plant and/or to a central processing unit. The objective function is to minimize the total annual cost for the treatment of flue gases, including the capital and operating costs for the different processing stages and the overall transportation costs associated with the system minus the sales of products plus the tax credit for reducing CO2 emissions. The results show several economic benefits.