INTERNATIONAL JOURNAL FOR ENGINEERING APPLICATION AND TECHNOLOGY ALGAE BASED BIOFUEL: A SYSTEMATIC LITERATURE REVIEW. Abstract

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1 IJFEAT INTERNATIONAL JOURNAL FOR ENGINEERING APPLICATION AND TECHNOLOGY ALGAE BASED BIOFUEL: A SYSTEMATIC LITERATURE REVIEW Nilesh R. Darokar 1, Pratik S. Urkande 2, Umesh G. Deogirkar 3, Shubham M. Matey 4 1 Student, Mechanical Department, J.D.I.E.T. Yavatmal,(M.S), India, nileshdarokar2013@gmail.com 2 student, Mechanical Department, J.D.I.E.T. Yavatmal,,(M.S),, India, pratikurkande@gmail.com 3 student, Mechanical Department, J.D.I.E.T. Yavatmal,,(M.S),India,deogirkarumesh@gmail.com 4 student, Mechanical Department, J.D.I.E.T. Yavatmal,,(M.S),India,Shubhu.m007@gmail.com Abstract This paper addresses the application of Algae to produce biofuel as a renewable energy resource. This review summarizes information related to the status of algae-based biofuel research and development efforts, including the efforts of a number of commercial biofuel companies. Biodiesel derived from green algae biomass has potential for high volume, cost effective production. This review paper examines particularly, the use algae as a source of biomass for fuel production is investigated, in terms of its productivity, practicality, and innovative potential to create a environmentally friendly, and renewable source of liquid fuel. It is better anticipation for the utilization of non renewable sources. This paper shows the by-products and fuels of algae like hydrogen, lipids, biodiesel, carbohydrate, and ethanol etc., also use of photobioreactor. This paper covers topics such as tarnsesterification, and hydroprocessing processes used to convert algal oil into the biofuels too. Index Terms:- Algae, lipids, biofuel, tarnsesterification, hydroprocessing, photobioreactor. 1.Introduction For the first time in 1942, Harder and Witch suggested that algae (specifically microalgae called diatoms) could be useful source of lipids (oils) as a both food and fuel source. Algae have recently received a lot of attention as a new biomass source for the production of renewable energy. Some of the main characteristics which set algae apart from other biomass sources are that algae (can) have a high biomass yield per unit of light and area, can have a high oil or starch content, do not require agricultural land, fresh water is not essential and nutrients can be supplied by wastewater and CO2 by combustion gas. The importance of algae has increased with the search for renewable energy sources. Even under highly unfavourable growth conditions, algae can thrive and produce valuable by products such as lipids (oils), carbohydrates, proteins, and various feedstocks that can be converted into biofuels and other useful materials. Algae can be used to make biofuel, Bioehanol and biobutanol and by some estimates can produce vastly superior amounts of vegetable oil, compared to terrestrial crops grown for the same purpose. Algae can be grown to produce hydrogen. In 1939 a German researcher named Hans Gaffron, while working at the University of Chicago, observed that the algae he was studying, Chlamydomonas reinhardtii (a green-algae), would sometimes switch from the production of oxygen to the production of hydrogen. Algae can be grown to produce biomass, which can be burned to produce heat and electricity. Algae can be cultivated in either open ponds or photobioreactors. Open ponds

2 are generally categorized as either natural waters, such as lakes, lagoons, and ponds, or artificial ponds or containers. While PBRs facilitate better control of the pure culture environment by providing optimal growth requirements such as amounts of carbon dioxide and water, temperature, exposure to light, mixing, culture density, ph levels, and gas supply and exchange rate. As these systems are closed, all of the specific growth requirements are internally maintained. Algae production can also yield additional secondary benefits such as the generation of hydrogen or methane, which can be used for transportation fuels. Other benefits of algae production can be gained from the removal of nitrogen and phosphorus from the treatment of municipal, agricultural, and industrial wastewater; the absorption of carbon dioxide from industrial flue gas; the production of protein for human or animal consumption; and the production of compounds for 1.1.Production of Biofuels From Algal Biomass by Fast Pyrolysis In recent years microalgae are gaining importance mainly due to their potential for fuel production wit and downs h zero carbon emissions. The main reason for the economical limitation of biofuels manufactured from algae is the high cost of culture media tream processes (extraction, purification, and transformation) on an industrial scale to make algal oil technologies economically feasible, the steps might be improved. In terms of culture media, it is in vogue to use waste water as a partial or complete source of nutrients (carbon dioxide, nitrogen, phosphorous, potassium, magnesium and some micronutriants) for algal growth as an alternative to reduce cultivation cost, whereas in term of oil recuperation and transformation fast pyrolysis is a cheaf alternative. Algae-based biofuels development has focused on the production of biodiesel (fatty acid methyl esters) from microalgae species with high neutral lipid contents, but these efforts have been hampered by energy-intensive lipid extraction techniques and limitations in algae cultivation, dewatering, and processing. Pyrolysis is the thermal decomposition of organic matter occuring in the absence of the oxygen or significantly less oxygen is present than it is required for complete combustion. Pyrolysis is the basic thermochemical process for coverting algae biomass into a useful fuels. In Pyrolysis, the biomass is degraded to bio-gas syngas and biochar at medium high temperature( C) in the absence of oxygen (Chen et al. 2009; Mohan et al. Fig.1:Algae Biodisel pharmaceuticals, cosmetics, and aquaculture purposes. The bottleneck of pyrolysis of algae into biooil is the dewatering pocess prior to pyrolysis which is energy intensive process. Pyrolysis technology can become economical if drying/dehydration process become inexpensive. 1.2.Algae cultivations culture For microalgae, the development of dedicated culture systems only started in the 1950s when algae were investigated as an alternative protein source for the increasing world population. Later, algae were researched for the interesting compounds they produce, to convert CO 2 to O 2 during space travel and for remediation of wastewater. The energy crisis in the 1970s initiated the research on algae as a source of renewable energy. For algae to grow, a few relatively simple conditions have to be met: light, carbon source, water, nutrients and a suitably controlled temperature. One important prerequisite to grow algae commercially for energy production is the need for large-scale systems which can range from very simple open air systems on- or offshore which expose the algae to the environment, to highly controllable, optimized but more expensive closed systems Open culture system:- The simplest open air algae cultivation systems are shallow, unstirred ponds whose sizes range from a few m 2 to 250 ha. The growing season is largely dependent on location and, aside from tropical areas, is limited to the warmer months. CO 2 dissolution from air into water limits the growth rate, making the yield per hectare relatively low. Other negative influences are the slow diffusion of nutrients and flotation and sedimentation of dead and living algae, limiting the usage of available

3 sunlight. Agitation can prevent this using a mechanical arm stirring in a circular motion. Major advantages of open ponds are that they are easy to construct and operate and their costs are minimal. Microorganism contamination, such as the invasion of fast-growing heterotrophic algae and bacteria, poses a significant problem in open pond systems and has restricted their successful use for commercial production of algae. Research efforts to deal with the problem of contamination involve the genetic modification of microalgae Closed culture system An alternative to open ponds are closed ponds where the control over the environment is much better than that for the open ponds. Closed systems or photobioreactors can be described as an enclosed, illuminated culture vessel designed for controlled biomass production of phototrophic liquid cell suspension cultures.the idea behind the closed pond is to close it off, to cover a pond or pool with a greenhouse. It allows more species to be grown, it allows the species that are being grown to stay dominant, and it extends the growing season, only slightly if unheated, and if heated it can produce year round. It is also possible to increase the amount of carbon-di-oxide in these quasi-closed systems, thus again increasing the rate of growth of algae. dissolved oxygen (DO) levels (Torzillo et al., 1986; Richmond et al., 1993; Molina et al., 2001). Some photobioreactor consists of a plate-shaped basic geometry with peaks and valleys arranged in regular distance. This geometry causes the distribution of incident light over a larger surface which corresponds to a dilution effect. Samson and Leduy (1985) developed a flat reactor equipped with fluorescence lamps. A year later, Ramos de Ortega and Roux (1986) developed an outdoor flat panel reactor by using thick transparent PVC materials. After this various designs of vertical alveolar panels and flat plate reactors for mass cultivation of different algae were reported (Tredici and Materassi, 1992; Hu et al., 1996; Zhang et al., 2002; Hoekema et al., Generally, flat-plate photobioreactors are made of transparent materials for maximum utilization of solar light energy. Accumulation of dissolved oxygen concentrations in flat-plate photobioreactors is relatively low compared to horizontal tubular photobioreactors. 2.Working of Photobioreactor Algae Photobioreacter A photobioreactor is a closed equipment which provides a controlled environment and enables high productivity of algae. The microorganisms use photosynthesis process to generate biomass from light and carbon dioxide and include plants, mosses, macroalgae, microalgae, cyanobacteria, and purple bacteria. PBRs facilitate better control of culture environment such as carbon dioxide supply, water supply, optimal temperature, efficient exposure to light, culture density, ph levels, gas supply rate, mixing regime, etc. Tubular photobioreactor is one of the most suitable types for outdoor mass cultures. Tubular photobioreactors are usually constructed with either glass or plastic tube and their cultures are recirculated either with pump or preferably with airlift system. Tubular photobioreactors consist of straight, coiled or looped transparent tubing arranged in various ways for maximizing sunlight capture. The tubes are oriented horizontally or vertically and are supplied from a central utilities installation with pump, sensors, nutrients and CO 2. One of the major limitations of tubular photobioreactor is poor mass transfer when a tubular photobioreactor is scaled up by increasing the diameter of tubes, the illumination surface to volume ratio would decrease also due to very high Fig. no 2. Working of photobioreactor A typical photo-bioreactor is a three phase closed reactor system with culture medium as the liquid phase; cells as the solid phase, and mostly, air as the gas phase. PBRs are complex systems composed of several subsystems. The key systems are:

4 Light system, Optical transmission system, Air handling & gas exchange systems, Mixing system, Nutrient system, Instrumentation system, Electrical system etc. Basically the working of photobioreactor starts with the feeding vessel supplied with water, Algae, CO 2 and nutrients. The flow progresses to the diaphragm pump which moderates the flow of the algae into the actual tube built into the pump is the CO2 inlet valve. The photobioreactor itself is used to promote biological growth by controlling tubes are made of acrylic and are designed to have light and dark intervals to enhance the growth rate. The photobioreactor has a built-in cleaning system that internally cleans the tubes without stopping the production. After the algae have completed the flow through the photobioreactor, it passes back to the feeding vessel. As it progresses through the hoses, the oxygen sensors determine how much oxygen has built up in the plant and this oxygen is released in the feeding vessel itself. It is also at this stage that the optical Cell Density sensor determines the harvesting rate. 3.Advantages of Photobioreactors Cultivation of algae is in controlled circumstances, hence potential for much higher productivity. Large surface-to-volume ratio. PBRs offer maximum efficiency in using light and therefore greatly improve productivity. Typically the culture density of algae produced is 10 to 20 times greater than bag culture in which algaeculture is done in bags - and can be even greater. Better control of gas transfer, reduction in evaporation of growth medium, more uniform temperature. Better protection from outside contamination. Space saving - Can be mounted vertically, horizontally or at an angle, indoors or outdoors. Reduced Fouling - Recently available tube self cleaning mechanisms can dramatically reduce fouling. Covering ponds does offer some of the benefits that are offered by photobioreactors, but enclosed systems will still provide better control of temperature, light intensity, better control of gas transfer, and larger surface area-tovolume ratio. An enclosed PBR design will enhance commercial algal biomass production by keeping algae genetics pure and reducing the possibility of parasite infestation. 4. Disadvantages of Photobioreactors Capital cost is very high. This is one of the most important bottlenecks that is hindering the progress of algae fuel industry. Despite higher biomass concentration and better control of culture decades have shown that the productivity and production cost in some enclosed photobioreactor systems parameters, data accumulated in the last two are not much better than those achievable in open-pond cultures. The technical difficulty in sterilizing these photobioreactors has hindered their application for algae culture for specific end-products such as high value pharmaceutical products. 5.By-products of Algae Since there are so many different algal species, algae as a group can produce a wide variety of products. Depending on the species and growing conditions, algae can yield a wide array of by products such as lipids, carbohydrates, and proteins Lipids And Biodiesel Fig.3:products of algae Lipids are long carbon chain molecules that serve as a structural component of the algal cell membrane. Lipids are a group of naturally occurring molecules that includes fats, waxes, sterols, fat soluble vitamins, monoglycerides, phospholipids and others. The main biological functions of lipids include storing energy, signalling, and acting as structural components of cell membranes. These lipids can be used as a liquid fuel in adapted engines as Straight Vegetable

5 Oil (SVO). In order to efficiently produce biodiesel from algae, strains have to be selected with a high growth rate and oil content. If an open culture system is used, the selected strain must have the ability to remain dominant under the applied conditions. Because of environmental conditions such as temperature, this means in practice that using a locally occurring strain is preferable in most cases (Sheehanet al., 1998). In a closed photobioreactor, competition from other algae can be prevented to some extent and optimal growth conditions can be more easily maintained. From all energy carriers produced from algae, biodiesel has received the most attention and is the only initiative which is on the border of pilot-scale and full-scale deployment Hydrocarbons :- One of the species of algae, Botryococcus braunii is well known for its ability to produce hydrocarbons which have been loosely described as equivalent to the gas-oil fraction of crude oil. (Hillenet al., 1982). Depending on the strain, these hydrocarbons are either C30 to C37 alkenes or C23 to C33 odd numbered alkenes (Ranga Rao and Ravishankar, 2007). These hydrocarbons are mainly accumulated on the outside of the cell, making extraction easier than when the cell wall has to be passed to reach the organics inside the cell (Wijffels, 2006). Other factors affecting growth of hydrocarbon production include availability of nitrogen and phosphate, light intensity and ph (Qin, 2005) Carbohydrates and ethanol :- Some Algae species contains starch over 50 percent have been reported. With new technologies, cellulose and hemicellulose can be hydrolysed to sugars (Hamelinck.et al.,2005), creating the possibility of converting an even larger part of algal dry matter to ethanol. Algae-specific technology for ethanol production is being developed, in which green algae are genetically modified to produce ethanol from sunlight and CO 2 (Deng and Coleman, 1999). Ethanol production from or by algae has very interesting prospects, but is currently only in the preliminary phase of research. Bioethanol can be made from Algae through a biochemical Process similar to corn ethanol. Algal biomass is ground, and the starch is converted by enzymes to sugar. Algal biomass can be used for biogas production. Digestion of algal biomass produces carbon dioxide, methane and ammonia. Some microalgae have been explored as potential methane sources Hydrogen :- Hydrogen offers great promise as a fuel of the future, since it can be applied in mobile applications with only water as exhaust product and no NOx emissions when used in a fuel cell. Currently, hydrogen gas is produced by the process of steam reformation of fossil fuels. Biological hydrogen production is possible; several bacteria can extract hydrogen from carbohydrates in the dark, a group called purple non-sulphur bacteria can use energy from light to extract more hydrogen gas (H 2 ) from a wider range of substrates, while green sulphur bacteria can make H 2 from H 2 S or S 2 O 3. These options are only interesting if a wastewater with these compounds is available (Rupprechtet al., 2006). Other algae can make hydrogen directly from sunlight and water, although only in the complete absence of oxygen. 6.Future scopes of algae for fuels production Algae biofuels have the potential to replace a significant portion of the total diesel used today with a smaller environmental footprint. In addition to this biofuel production can be carried out using marginal land and saline water, placing no additional pressure on land needed. Florentinus et al. (2008) assess the theoretical potential of algae for biofuels production for the several hundred EJ. yr -1. More than 50 years of research have demonstrated the potential of various microalgal species to produce several chemical intermediates and hydrocarbons that can be converted into biofuels. Proponents of algae biofuels make ambitious claims of the potential of the photosynthesis production system to contribute to the world s future fuel needs. Algae biofuels could completely replaced all petroleum derived transport fuels or even provide a significant contribution to liquids fuels on simple assessment, but there is need to develop this information. Such a contribution of algae biofuel is assessed against US Energy Information Agency growth projections. By 2030, oil consumption is expected to increase to ca. 6.2 TL.yr -1 (106 million bbl.d -1 ) with 66% of this growth is likely to occur in non OECD countries in Asia. Transportation fuel use is expected to grow slightly to ca. 56% of total oil production. Over the same time period, biofuel will maintain a relatively steady share of unconventional fuel production and grow to between 277 GL.yr -1 and 416 GL.yr -1 (4.8 to 7.2 billion bbl.d -1, or 8% to 12% of the liquid transportation fuel supply). The EIA uses ca. 340Gl.yr -1 as a reference case for total biofuel production 2030.

6 The 5% contribution of algal biofuels to total biofuel supply by 2030 would require the construction of ML facility. When the technical uncertainty is considered it seems unlikely that the first large scale plant would be commissioned before the middle of the coming decade, and even this would be ambitious. Approaches that rely on molecular biology to achieve breakthroughs. Microalgae include a wide variety of photosynthetic microorganism capable of fixing CO 2 from the atmosphere and water to produce biomass more efficiently asnd rapidly than terrestrial plants. Numerous algal strain as the fuction of laboratory to produced more than that 50 percent of their biomass as lipid with much of material for biodiesel fuels called from triacyglycerides (TAG s ). An additional benefit of growing algae as a biofuels feedstock isthat they can be cultivated on otherwise non-productive (i.e., non-arable) land that is unsuitable for agriculture or in brackish, saline, and waste water that has little competing demand, offering the prospect of a biofuel that does not further tax already limited resources. Using algae to produce feedstocks for biofuels production could have little impact on the production of food and other products derived from terrestrial crops, but will utilize water resources, which will need a life cycle assessment to identify areas for sustainable production. Algae have the potential to reduce the generation of greenhouse gas (GHG) and to recycle CO 2 emissions from flue gases from power plant and natural gas operations as indicated by preliminary life cycle assessments. In the future, an algal-based biorefinery could potentially integrate several different conversion technologies to produce biofuels including biodiesel, green diesel and green gasoline(generated by catalytic hydroprocessing and catalytic cracking of vegetable oils, respectively), aviation fuel (commercial and military), ethanol, and methane, as well as valuable co-products including oils, protein, and carbohydrates. refining (e.g. for desulphurisation and heavy oil upgrading), has been demonstrated for biomass derived oil processing at the ca. 10 Ml.yr -1 scale, and is currently at the commissioning or early production stages in larger capacity facilities. 8.Transesterification In this process, the relatively viscous TAGs are reacted with methanol in the presence of a catalyst to produce FAME, which more closely resemble petroleum-based diesel fuel and glycerol as a coproduct (see Figure ). High conversions are achieved in this reversible reaction by either adding an excess of methanol of removing glycerol as it is formed; both strategies have been used in commercial processes (van Gerpen et al., 2004). Fig. No. 4:Transesterification There are a number of variations of the transesterification process and biodiesel manufacturers will optimize the process for the each feedstock by balancing yields against equipment, catalyst, methanol and energy costs. In the case of algal biofuels, the feedstock composition is uncertain and will likely vary over time since changes in production temperature, light intensity and nutrient levels all affect algal lipid composition. Consequently, process optimization (albeit a known art) will need continuous attention in a production environment with the flexibility to deal with varying feedstock composition.. 7.Conversion of Algal Oil to Biofuels The transesterification of biomass derived lipids to fatty acid methyl ester (FAME) liquid fuels is well established and practised on large scales. The alternative hydroprocessing (or hydrotreating) process has wide spread use in petroleum 9.Hydroprocessing The alternative path from biomass derived lipids to liquid fuels is hydrotreating or hydroprocessing, where the oil is reacted with hydrogen over a catalyst and then isomerised to produce a targeted mixture of alkanes, water, CO 2 and CO (see Figures 2-14 & 2-15). The alkane mixture can be fractionated to produce a synthetic kerosene jet fuel

7 and hydrogenation-renewable diesel (HDRD) or green diesel. HDRD is compatible with petroleum processes and existing fuel infrastructure, and can be blended with petroleum products in any proportion. Fig. No. 5:hydroprocessing The glycerol moiety of the TAG is converted to propane, which can be combusted to provide process heat or liquefied and sold as LPG. 10.The Need for Innovation Reported favourable economic feasibility assessments are often based on biomass production rates and oil yields that are two to three times those achievable in existing production systems. These high growth rates and oil yields are yet to be demonstrated at any scale and over periods of time sufficient to provide assurance for investment in full scale production. Bioprospecting (isolation of algal species from nature), selective breeding and molecular biological strategies all offer potential to improve growth rate and oil yield. Likewise, further R&D is needed to identify and demonstrate high yield, low cost and energy efficient oil extraction. Success in these R&D endeavours has obvious benefit to the economic viability of an algal biofuels industry. There is a need for innovation in all elements of algal biofuels production to address technical inefficiencies, which appear to represent significant challenges to the development of economically viable algal biofuel enterprises. Research needs, funding sources and current activities in the USA are reviewed in greater detail in Appendix A. The review clearly indicates the interest at all levels of government and the in private sector in the development of algal biofuels technologies and enterprises. 11.Conclusions The potential for production of algal biofuels has captured the attention of the nation and the world. It is written up in scientific literature and the popular press. It has stimulated activity in academic labs, start-up companies, large oil companies, and end users. The potential of algal biofuels must be framed by the realization that virtually none of the technologies necessary for their production (with the exception of the conversion of the algal oils themselves to biodiesel or green diesel) have yet been demonstrated at scale or in an integrated fashion under conditions resembling a full-scale production facility. The potential of algal biofuels is based upon benchscale observations, limited outdoor production data, extrapolation, assumption, and limited critical and economic analysis. The technical feasibility has been proven at small scale and, in fact, small samples of algal biodiesel have been produced, but economic feasibility is unknown. It is in recognition of the magnitude of its potential; however, this report has attempted to summarize the state of algae-to-fuels technology and document the economic challenges that must be met before algal biofuel can be produced commercially. It is likely that a significant amount of research and a number of breakthroughs are needed to make algal biofuels a commercial reality. The economic analysis in this report indicates that the major cost for fuel production comes from the growth and harvesting of the algal biomass. The current effort in algal biofuels research seems to follow that of the biotech industry in general, with basic research carried out mainly at academic labs, transitional work divided among academic labs, national labs, start-up companies, and scale-up split between the start-up companies and the larger commercial organizations that will likely play a major role in large-scale manufacturing. As with other areas of biotechnology, it may become difficult to distinguish between purely academic labs and commercial start-ups working with algal biofuels. Commercialization will require R&D efforts at both pilot and production scale expensive efforts that require high-level financial support and can only be justified once technical and cost issues have been addressed. 12.Acknowledgments Algae biofuels can make positive contribution to sustenable development in developing countries. Large uncertainty make algae biofuels currently unsuitable as a priority for many developing countries. We would like to acknowledge the valuable contribution to the Ashok Pande author of book BIODIESEL FROM ALGAE. The necessary information obtained from a report to IEA Bioenergy with authors Al Darzins (NREL),

8 Philip Pienkos (NREL), Les Edye (BioIndustry Partners. 13.Reference 1. Dehue, B., Hamelinck, C., Reece, G., de Lint,S., Archer, R. and Garcia, E. (2008b). Sustainability Reporting Within the RTFO: Framework Report. Ecofys. Utrecht, The Netherlands, Ecofys. 2. Ranga Rao, A. and Ravishankar, G. A. (2007). "Influence of CO2 on growth and hydrocarbon production in Botryococcus braunii." J. Microbiol. Biotechnol. 17(3): Wijffels, R. (2006). Energie via microbiologie: Status entoekomstperspectief voor Nederland. Utrecht, SenterNovem. Wijffels, R. (2007). Presentation Microalgae for production of energy. 4. Qin, J. (2005). Bio-hydrocarbons from algae : impacts of temperature, light and salinity on algae growth. Barton, Rirdc. 5. Deng, M. D. and Coleman, J. R. (1999). "Ethanol synthesis by genetic engineering in cyanobacteria." Appl. Environ. Microbiol. 65(2): Rupprecht, J., Hankamer, B., Mussgnug, J.H., Ananyev, G., Dismukes, C. and Kruse, O. (2006). "Perspectives and advances of biological H2production in microorganisms." Appl. Microbiol. Biotechnol. 72(3): Hamelinck, C. N., van Hooijdonk, G. and Faaij, A. P.C. (2005). "Ethanol from lignocellulosic biomass: techno-economic performance in short-, middle- and long-term." Biomass Bioenerg. 28(4):