Date palm is one of the principal agricultural products in the arid and semi-arid region of the world, especially Middle East and North Africa (MENA) region. There are more than 120 million date palm trees worldwide yielding several million tons of dates per year, apart from secondary products including palm midribs, leaves, stems, fronds and coir. The Arab world has more than 84 million date palm trees with the majority in Egypt, Iraq, Saudi Arabia, Iran, Algeria, Morocco, Tunisia and United Arab Emirates.
Date palm biomass is found in large quantities across the Middle East
Egypt is the world’s largest date producer with annual production of 1.47 million tons of dates in 2012 which accounted for almost one-fifth of global production. Saudi Arabia has more than 23 millions date palm trees, which produce about 1 million tons of dates per year.
Biomass Potential of Date Palm Wastes
Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits. Some studies have reported that Saudi Arabia alone generates more than 200,000 tons of date palm biomass each year.
Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in dates-producing nations. In countries like Iraq and Egypt, a small portion of palm biomass in used in making animal feed.
The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date biomass an excellent waste-to-energy resource in the MENA region.
Technology Options for Date Palm Biomass Utilization
A wide range of thermal and biochemical technologies exists to tap the energy stored in date palm biomass to useful forms of energy. The low moisture content in date palm wastes makes it well-suited to thermochemical conversion technologies like combustion, gasification and pyrolysis which may yield steam, syngas, bio oil etc.
On the other hand, the high volatile solids content in date palm biomass indicates its potential towards biogas production in anaerobic digestion plants, possibly by codigestion with sewage sludge, animal wastes and/and food wastes. The cellulosic content in date palm wastes can be transformed into biofuel (bioethanol) by making use of the fermentation process.
The highly organic nature of date palm waste makes it highly suitable for compost production which can be used to replace chemical fertilizers in date palm plantations. Thus, abundance of date palm trees in the MENA and the Mediterranean region, can catalyze the development of biomass and biofuels sector in the region.
High oil prices, competing demands between foods and other biofuel sources, and the world food crisis, have ignited interest in algaculture (farming of algae) for making vegetable oil, biodiesel, bioethanol, biogasoline, biomethanol, biobutanol and other biofuels. Algae can be efficiently grown on land that is not suitable for agriculture and hold huge potential to provide a non-food, high-yield source of biodiesel, ethanol and hydrogen fuels.
Several recent studies have pointed out that biofuel from microalgae has the potential to become a renewable, cost-effective alternative for fossil fuel with reduced impact on the environment and the world supply of staple foods, such as wheat, maize and sugar.
What are Algae?
Algae are unicellular microorganisms, capable of photosynthesis. They are one of the world’s oldest forms of life, and it is strongly believed that fossil oil was largely formed by ancient microalgae. Microalgae (or microscopic algae) are considered as a potential oleo-feedstock, as they produce lipids through photosynthesis, i.e. using only carbon, water, sunlight, phosphates, nitrates and other (oligo) elements that can be found in residual waters.
Oils produced by diverse algae strains range in composition. For the most part are like vegetable oils, though some are chemically similar to the hydrocarbons in petroleum.
Advantages of Algae
Apart from lipids, algae also produce proteins, isoprenoids and polysaccharides. Some strains of algae ferment sugars to produce alcohols, under the right growing conditions. Their biomass can be processed to different sorts of chemicals and polymers (Polysaccharides, enzymes, pigments and minerals), biofuels (e.g. biodiesel, alkanes and alcohols), food and animal feed (PUFA, vitamins, etc.) as well as bioactive compounds (antibiotics, antioxidant and metabolites) through down-processing technology such as transesterification, pyrolysis and continuous catalysis using microspheres.
Algae can be grown on non-arable land (including deserts), most of them do not require fresh water, and their nutritional value is high. Extensive R&D is underway on algae as raw material worldwide, especially in North America and Europe with a high number of start-up companies developing different options.
Most scientific literature suggests an oil production potential of around 25-50 ton per hectare per year for relevant algae species. Microalgae contain, amongst other biochemical, neutral lipids (tri-, di-, monoglycerides free fatty acids), polar lipids (glycolipids, phospholipids), wax esters, sterols and pigments. The total lipid content in microalgae varies from 1 to 90 % of dry weight, depending on species, strain and growth conditions.
What is Algae Biorefinery
In order to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, carbohydrates) should be used and therefore biorefining of microalgae is very important for the selective separation and use of the functional biomass components.
The term algae biorefinery was coined to describe the production of a wide range of chemicals and biofuels from algal biomass by the integration of bio-processing and appropriate low environmental impact chemical technologies in a cost-effective and environmentally sustainable.
If biorefining of microalgae is applied, lipids should be fractionated into lipids for biodiesel, lipids as a feedstock for the chemical industry and essential fatty acids, proteins and carbohydrates for food, feed and bulk chemicals, and the oxygen produced can be recovered as well.
The potential for commercial algae production, also known as algaculture, is expected to come from growth in translucent tubes or containers called photo bioreactors or in open systems (e.g. raceways) particularly for industrial mass cultivation or more recently through a hybrid approach combining closed-system pre-cultivation with a subsequent open-system.
Advantages of Algae Biorefinery
The major advantages of an algae biorefinery include:
Use of industrial refusals as inputs ( CO2,wastewater and desalination plant rejects)
Large product basket with energy-derived (biodiesel, methane, ethanol and hydrogen) and non-energy derived (nutraceutical, fertilizers, animal feed and other bulk chemicals) products.
Not competing with food production (non-arable land and no freshwater requirements)
Better growth yield and lipid content than crops.
Indeed, after oil extraction the resulting algal biomass can be processed into ethanol, methane, livestock feed, used as organic fertilizer due to its high N:P ratio, or simply burned for energy cogeneration (electricity and heat). If, in addition, production of algae is done on residual nutrient feedstock and CO2, and production of microalgae is done on large scale in order to lower production costs, production of bulk chemicals and fuels from microalgae will become economically, environmentally and ethically extremely attractive.
Biochar is a carbon-rich, fine-grained residue which can be produced either by ancient techniques (such as covering burning biomass with soil and allowing it to smoulder) or state-of-the-art modern biomass pyrolysis processes. Combustion and decomposition of woody biomass and agricultural residues results in the emission of a large amount of carbon dioxide. Biochar can store this CO2 in the soil leading to reduction in GHGs emission and enhancement of soil fertility.
Biochar holds the promise to tackle chronic human development issues like hunger and food insecurity, low agricultural productivity and soil depletion, deforestation and biodiversity loss, energy poverty, water pollution, air pollution and climate change. Let us have a close look at some of the most promising applications of biochar.
1. Use of biochar in animal farming
At present approx. 90% of the biochar used in Europe goes into animal farming. Different to its application to fields, a farmer will notice its effects within a few days. Whether used in feeding, litter or in slurry treatment, a farmer will quickly notice less smell. Used as a feed supplement, the incidence of diarrhoea rapidly decreases, feed intake is improved, allergies disappear, and the animals become calmer.
In Germany, researchers conducted a controlled experiment in a dairy that was experiencing a number of common health problems: reduced performance, movement disorder, fertility disorders, inflammation of the urinary bladder, viscous salivas, and diarrhoea. Animals were fed different combinations of charcoal, sauerkraut juice or humic acids over periods of 4 to 6 weeks.
Experimenters found that oral application of charcoal (from 200 to 400 g/day), sauerkraut juice and humic acids influenced the antibody levels to C. botulinum, indicating reduced gastrointestinal neurotoxin burden. They found that when the feed supplements were ended, antibody levels increased, indicating that regular feeding of charcoal and other supplements had a tonic effect on cow health.
2. Biochar as soil conditioner
In certain poor soils (mainly in the tropics), positive effects on soil fertility were seen when applying untreated biochar. These include the higher capacity of the soil to store water, aeration of the soil and the release of nutrients through raising the soil’s pH value. In temperate climates, soils tend to have humus content of over 1.5%, meaning that such effects only play a secondary role.
Indeed, fresh biochar may adsorb nutrients in the soil, causing at least in the short and medium term – a negative effect on plant growth. These are the reasons why in temperate climates biochar should only be used when first loaded with nutrients and when the char surfaces have been activated through microbial oxidation.
The best method of loading nutrients is to co-compost the char. This involves adding 10–30% biochar (by volume) to the biomass to be composted. Co-composting improves both the biochar and the compost. The resulting compost can be used as a highly efficient substitute for peat in potting soil, greenhouses, nurseries and other special cultures.
Because biochar serves as a carrier for plant nutrients, it can produce organic carbon-based fertilizers by mixing biochar with such organic waste as wool, molasses, ash, slurry and pomace. These are at least as efficient as conventional fertilizers, and have the advantage of not having the well-known adverse effects on the ecosystem. Such fertilizers prevent the leaching of nutrients, a negative aspect of conventional fertilizers. The nutrients are available as and when the plants need them. Through the stimulation of microbial symbiosis, the plant takes up the nutrients stored in the porous carbon structure and on its surfaces.
A range of organic chemicals are produced during pyrolysis. Some of these remain stuck to the pores and surfaces of the biochar and may have a role in stimulating a plant’s internal immune system, thereby increasing its resistance to pathogens. The effect on plant defence mechanisms was mainly observed when using low temperature biochars (pyrolysed at 350° to 450°C). This potential use is, however, only just now being developed and still requires a lot of research effort.
3. Biochar as construction material
The two interesting properties of biochar are its extremely low thermal conductivity and its ability to absorb water up to 6 times its weight. These properties mean that biochar is just the right material for insulating buildings and regulating humidity. In combination with clay, but also with lime and cement mortar, biochar can be added to clay at a ratio of up to 50% and replace sand in lime and cement mortars. This creates indoor plasters with excellent insulation and breathing properties, able to maintain humidity levels in a room at 45–70% in both summer and winter. This in turn prevents not just dry air, which can lead to respiratory disorders and allergies, but also dampness and air condensing on the walls, which can lead to mould developing.
As per study by the Ithaka Institute’s biochar-plaster wine cellar and seminar rooms in the Ithaka Journal. Such biochar-mud plaster adsorbs smells and toxins, a property not just benefiting smokers. Biochar-mud plasters can improve working conditions in libraries, schools, warehouses, factories and agricultural buildings.
Biochar is an efficient adsorber of electromagnetic radiation, meaning that biochar-mud plaster can prevent “electrosmog”. Biochar can also be applied to the outside walls of a building by jet-spray technique mixing it with lime. Applied at thicknesses of up to 20 cm, it is a substitute for Styrofoam insulation. Houses insulated this way become carbon sinks, while at the same time having a more healthy indoor climate. Should such a house be demolished at a later date, the biochar-mud or biochar-lime plaster can be recycled as a valuable compost additive.
Soil substrates – Highly adsorbing and effective for plantation soil substrates for use in cleaning wastewater; in particular urban wastewater contaminated by heavy metals.
A barrier preventing pesticides getting into surface water – berms around fields and ponds can be equipped with 30-50 cm deep barriers made of biochar for filtering out pesticides.
Treating pond and lake water – biochar is good for adsorbing pesticides and fertilizers, as well as for improving water aeration.
5. Use of biochar in wastewater treatment – Our Project
The biochar grounded to a particle size of less than 1.5 mm and surface area of 600 – 1000 m2/g. The figure below is the basic representation of production of biochar for wastewater treatment.
We conducted a study for municipal wastewater which was obtained from a local municipal treatment plant. The municipal wastewater was tested for its physicochemical parameters including pH, chemical oxygen demand (COD), total suspended solids (TSS), total phosphates (TP) and total Kjeldahl nitrogen (TKN) using the APHA (2005) standard methods.
Bio filtration of the municipal wastewater with biochar acting as the bio adsorbent was allowed to take place over a 5 day period noting the changes in the wastewater parameters. The municipal wastewater and the treated effluent physicochemical.
The COD concentration in the municipal wastewater decreased by 90% upon treatment with bio-char. The decrease in the COD was attributed to the enhanced removal of bio contaminants as they were passed through the biochar due to the biochar’s adsorption properties as well as the high surface area of the bio char. An 89% reduction in the TSS was observed as the bio filtration process with bio char increased from one day to five days
The TKN concentration in the wastewater decreased by 64% upon treatment with bio char as a bio filter. The TP in the wastewater decreased by 78% as the bio filtration time with biochar increase. The wastewater pH changed from being alkaline to neutral during the treatment with biochar over the 5 day period
6. Use of Biochar in Textiles
In Japan and China bamboo-based biochar are already being woven into textiles to gain better thermal and breathing properties and to reduce the development of odours through sweat. The same aim is pursued through the inclusion of biochar in shoe soles and socks.
Nowadays, biofuels are in high demand for transportation, industrial heating and electricity generation. Different technologies are being tested for using MSW as feedstock for producing biofuels. This article will provide brief description of biochemical and thermochemical conversion routes for the production of biofuels from municipal solid wastes.
The waste is collected and milled, particles are shredded to reduce the size of 0.2-1.22 mm. MSW is pretreated to improve the accessibility of enzymes and make use of the enzymes in the bacteria for biological degradation on solid waste. The mixture of biomass is mixed with sulfuric acid and sodium hydroxide and autoclaved. After steam treatment, the mixture is filtered and washed with deionized water. The pre-treated mixture is then dried and drained overnight. The pre-treatment process improves the formation of sugars by enzymatic hydrolysis, avoids the loss of carbohydrate and avoids the formation of by-products inhibitory.
After pre-treatment (pre-hydrolysis), the mixture undergoes enzymatic hydrolysis for conversion of polysaccharides into monomer sugars, such as glucose and xylose. The common enzymes used for starch-based substrates are amylase, pullulanase, isomylase and glucoamylase. Whereas for lignocellulose based substrates cellulases and glucosidases.
Finally, the mixture is fermented; sugars are converted to ethanol by using microorganisms such as, bacteria, yeast or fungi. The cellulosic and starch hydrolysates ethanolic fermentation were fermented by M. indicus at 37 °C for 72 h. The fungus uses the hexoses and pentoses sugars with a high concentration of inhibitors (i.e. furfural, hydroxymethyl furfural, and acetic acid).
The composition of MSW feedstock effects the yield of the subsequent processes. A high composition of food and vegetable waste is more desirable, as these wastes are easily degradable and result in high yields compared to paper and cardboard.
Gasification process is carried out by treating carbon-based material with either oxygen or steam to produce a gaseous fuel which requires high temperature and pressure. It can be described as partial oxidation of the waste. At first waste is reduced in size and dried to reduce the amount of energy used in the gasifier.
Layout of a Typical Biomass Gasification Plant
The carbonaceous material oxidizes (combines with oxygen) to produce syngas (carbon monoxide and hydrogen) along with carbon dioxide, methane, water vapor, char, slag, and trace gases (depending on the composition of the feedstock). The syngas is then cleaned to remove any sulfur or acid gases and trace metals (depending on the composition of the feedstock).
The main uses of syngas are direct burning on site to provide heat or energy (by using boilers, gas turbines or steam driven engines) and refined to liquid fuels such as gasoline or ethanol.
Syngas can then be converted into biofuels and chemicals via catalytic processes such as the Fischer-Tropsch process. The Fischer-Tropsch process is a series of catalytic chemical reactions that convert syngas into liquid hydrocarbons by applying heat and pressure. Hydrocracking, hydro-treating, and hydro-isomerization can also be part of the “upgrading” process to maximize quantities of different products.
Biochemical conversion of biomass involves use of bacteria, microorganisms and enzymes to breakdown biomass into gaseous or liquid fuels, such as biogas or bioethanol. The most popular biochemical technologies are anaerobic digestion (or biomethanation) and fermentation. Anaerobic digestion is a series of chemical reactions during which organic material such as human waste is decomposed through is decomposed through the metabolic pathways of naturally occurring microorganisms in an oxygen depleted environment.
Biomass wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels.If you are writing an essay related to this topic experts from the best custom essay service in usa advise you to read and analyze the information provided in this article.
Anaerobic digestion is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas. Anaerobic digestion is a reliable technology for the treatment of wet, organic waste. Organic waste from various sources is biochemically degraded in highly controlled, oxygen-free conditions circumstances resulting in the production of biogas which can be used to produce both electricity and heat. Biomass conversion technologies are slowing being built for home boilers also.
The team over at The Solar Advantage says this, ‘”Almost any organic material can be processed with anaerobic digestion. This includes biodegradable waste materials such as municipal solid waste, animal manure, poultry litter, food wastes, sewage and industrial wastes.”
An anaerobic digestion plant produces two outputs, biogas and digestate, both can be further processed or utilized to produce secondary outputs. Biogas can be used for producing electricity and heat, as a natural gas substitute and also a transportation fuel. A combined heat and power plant system (CHP) not only generates power but also produces heat for in-house requirements to maintain desired temperature level in the digester during cold season. In Sweden, the compressed biogas is used as a transportation fuel for cars and buses. Biogas can also be upgraded and used in gas supply networks. You can find learnerships in these specialised fields for those interested in a career in this sector.
Working of Anaerobic Digestion Process
Digestate can be further processed to produce liquor and a fibrous material. The fiber, which can be processed into compost, is a bulky material with low levels of nutrients and can be used as a soil conditioner or a low level fertilizer. A high proportion of the nutrients remain in the liquor, which can be used as a liquid fertilizer. Many companies are use R&D tax credits to carry out these initiatives.
A variety of fuels can be produced from waste resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues. Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking, apart from powering home boilers.
The largest potential feedstock for ethanol is lignocellulosic biomass wastes, which includes materials such as agricultural residues (corn stover, crop straws and bagasse), herbaceous crops (alfalfa, switchgrass), short rotation woody crops, forestry residues, waste paper and other wastes (municipal and industrial). Bioethanol production from these feedstocks could be an attractive alternative for disposal of these residues. Importantly, lignocellulosic feedstocks do not interfere with food security.
Ethanol from lignocellulosic biomass is produced mainly via biochemical routes. The three major steps involved are pretreatment, enzymatic hydrolysis, and fermentation. Biomass is pretreated to improve the accessibility of enzymes. After pretreatment, biomass undergoes enzymatic hydrolysis for conversion of polysaccharides into monomer sugars, such as glucose and xylose. Subsequently, sugars are fermented to ethanol by the use of different microorganisms.
Used cooking oil is one of the major sources of biofuel. As the push for alternative sources of energy is enhanced, biofuel production has also gone into high gear. As such, it has moved from the unsustainable food sources to more sustainable sources such as used cooking oil.
With the adoption of used cooking oil as a source of biofuel, producers have gained numerous benefits. Here are a few.
Cheap to procure
One of the major benefits of used cooking oil as a source of biofuels is that it is cheap to procure. Sources of used cooking oil abound, and they are happy to have it offloaded off their homes and their premises.
Most times, you will find that those that have the used cooking oil will pay to have it taken away from them. As such, hotels and restaurants and even households pay biofuel companies to collect it from their premises.
This makes the process of collecting used cooking oil efficient and affordable. This is a huge first step in the recycling of used cooking oil into biofuel.
Easy to process
Once the used cooking oil arrives at the processing center, it passes through a chemical process that converts the used cooking oil to biofuel.
The process is easy and uses easily available reagents. This process eliminates all the impurities within the used cooking oil. It is a five-stage chemical process that culminates in the conversion of used cooking oil into a useful biofuel.
Another benefit derived from used cooking oil as a biofuel, is the fact that it is environmentally friendly. Biofuels produced from used cooking oil can replace fossil fuel diesel in a world ravaged by global warming. It burns efficiently and thus has almost zero emissions that can be harmful to the environment.
Biofuel from used cooking oil can easily replace diesel in vehicles and plant machinery. After processing, the resulting biofuel can easily replace diesel in numerous existing machines and vehicles. Many of these machines will not need any re calibration for them to use this fuel.
The use of used cooking oil biofuel will thus save money for the users and also help them reduce their impact on the environment. Company trucks and plant machinery that use diesel can easily switch to biofuels and companies will see a significant savings in their fuel expense as well.
Can be used to manufacture diverse products
Used cooking oil when recycled is not limited only to the production of biofuels. Rather, it can be used to produce a range of other products and materials that could be a significant business unit.
Used cooking oil can be processed into raw materials for animal and pet feeds. Used cooking oil contains high amounts of protein that will beneficial in animal feed.
Further, used cooking oil can be used to make soap, lubricants and many other useful products.
With these other products, companies that process used cooking oil have a range of products to get to the market to ensure that they remain afloat profitably.
Alternative source of energy for small businesses
Many small businesses have adopted the use of biofuel that is produced from recycled used cooking oil. This helps them save on high energy costs by using it to power some of the processes that use electricity and other expensive sources of energy.
There are many biofuel producing companies that use used cooking oil as part of their raw materials. I have outlined why it is beneficial not only to biofuel producers, but also to the end users of the biofuel that comes from it.
Biofuel commercialization has proved to be costly and lingering than expected due to its high production cost and modification to flexibility in engines. Drop-in fuels are alternatives to existing liquid fuels without any significant modification in engines and infrastructures. According to IEA, “Drop-in biofuels are liquid bio-hydrocarbons that are functionally equivalent to petroleum fuels and are fully compatible with existing petroleum infrastructure”.
What are Drop-in Biofuels
Drop-in biofuels are can be produced from oilseeds via trans-esterification, lignocellulosic biomass via thermochemical process, sugars and alcohol via biochemical conversion or by hybrids of the above methods. Drop-in fuels encompass high hydrogen to carbon ratio with no/low sulfur and oxygen content, low water solubility and high carbon bond saturation. In short drop-in fuel is a modified fuel with close functional resemblance to fossil fuel.
Existing biofuels – bioethanol and biodiesel – have wide variation from fossil fuels in their blend wall properties – high oxygen content, hydrophilicity, energy density and mainly compatibility in existing engines and infrastructures. Oxygenated groups in biofuel have a domino effect such as reduction in the energy density, production of impurities which are highly undesirable to transportation components, instability during storage etc.
Reduced sulphur oxide emissions by ultra low sulphur content.
Reduced ignition delay by high cetane value
Reduced hydrocarbons and nitrogen oxides emissions
Low aromatic content
Low olefin content, presence of olefin compounds undergo auto-oxidation leading to surface depositions.
High saturates, therefore leaving minimum residues
Low particulate emissions
No oxygenates therefore has high stability.
Potential Biomass Feedstock
Drop-in biofuels can be produced from various biomass sources- lipids (vegetable oils, animal fats, greases, and algae) and lignocellulosic material (such as crop residues, woody biomass, and dedicated energy crops). The prominent technologies for biomass conversion to drop-in fuel are the thermochemical and the biochemical process.
The major factor playing role in selection of biomass for thermochemical methods is the energy content or heating value of the material, which is correlated with ash content. Wood, wood chips accounts for less than 1% ash content, which is favorable thermal processing than biochemical process, whereas straws, husks, and majority of the other biomass have ash content ranging up to 25% of dry mass.
Free sugar generating plants such as sugarcane and sweet sorghum, are desirable feedstock for Acetone-Butanol-Ethanol fermentation and have been widely implemented. Presently there is a focus to exploit lignocellulosic residues, rich in hydrocarbon, for fuel production. However, this biomass requires harsh pretreatment to remove lignin and to transform holocellulose (cellulose & hemicelluloses) into fermentable products.
The lignocellulose transformation technology must be circumspectly chosen by its life cycle assessment, as it resists any changes in their structural integrity owing to its complexity. Lignocellulosic biomass, when deoxygenated, has better flexibility to turn to drop-in fuels. This is because, in its native state of the feedstock, each oxygen atom consumes two hydrogen atoms during combustion which in turn reduces effective H: C ratio. Biomass feedstock is characterized with oxygen up to 40%, and higher the oxygen content higher it has to be deoxygenated.
Thermochemical methods adopted for biomass are pyrolysis and gasification, on thermolysis of biomass produce intermediate gas (syngas) and liquid (bio crude) serving as precursors for drop-in fuel. Biomass when exposed to temperature of 500oC-600oC in absence of oxygen (pyrolysis) produce bio-oil, which constitutes a considerable percentage of oxygen. After down streaming by hydroprocessing (hydrotreating and hydrocracking) the rich hydrocarbon tar (bio-oil) can be converted to an efficient precursor for drop-in fuel.
At a higher temperature, above 700, under controlled oxygen, biomass can be converted to liquid fuel via gas phase by the process, gasification. Syngas produced is converted to liquid fuel by Fischer-Tropsch with the help of ‘water gas shift’ for hydroprocessing. Hydroprocessing after the thermochemical method is however costly and complex process in case of pyrolysis and inefficient biomass to fuel yield with gasification process.
The advanced biocatalytic processes can divert the conventional sugar-ethanol pathway and convert sugars to fatty acids. Modified microbial strain with engineered cellular machineries, can reroute the pathway to free fatty acid that can be transformed into butanol or drop-in fuel with necessary processing.
Schematic for the preparation of jet fuel from biomass
Biological processing requires operation under the stressful conditions on the organisms to reroute the pathways, in additional to lowering NADPH (hydrogen) consumption. Other value added products like carboxylic acid, polyols, and alcohol in the same biological routes with lower operational requirements have higher market demands and commercial success. Therefore little attention is given by chemical manufacturers to the biological pathways for drop-in fuel production.
The mechanisms of utilization of lignocellulosic biomass to fuel by biological pathway rely heavily on the availability of monomeric C5 and C6 sugars during fermentation. Ethanol is perhaps the best-known and commercially successful alcohol from ABE fermentation. However, butanol has various significant advantages over ethanol- in the perception of energy content, feasibility to existing infrastructures, zero blend wall, safety and clean aspects.
Although butanol is a closer drop-in replacement, existing biofuel ethanol, is a major commercial competitor. Low yield from fermentation due to the toxicity of butanol and complexity in down streaming are the vital reasons that hamper successful large scale butanol production.
Challenges to Overcome
Zero oxygen and sulphur content mark major challenges for production of drop-in fuels from conventional biomass. This demands high hydrogen input on the conventional biomass, with H: C ratio below 0.5, like sugar, starch, cellulose, lignocellulose to meet the effective hydrogen to carbon ratio of 2 as in drop-in fuel. This characterizes most of the existing biomass feedstock as a low-quality input for drop-in fuels. However oleochemicals like fats, oils, and lipids have closer H: C ratio to diesel, gasoline and drop-in fuels, thus easier to conversion.
Oleochemical feedstock has been commercially successful, but to prolong in the platform will be a major challenge. Lipid feedstock is generally availed from crop-based vegetable oil, which is used in food sectors. Therefore availability, food security concerns, and economics are the major constraints to sustaining the raw material. Consequently switching to lignocellulosic biomass feedstock for drop-in holds on.
Despite the hurdles on biomass characteristics and process technology for drop-in fuel, it is a vital requirement to switch to better replacement fuel for fossil fuel, considering environmental and economic benefits. Understanding its concepts and features, drop-in fuel, can solve existing greenhouse emission debate on current biofuels. Through crucial ambiguities existing on future of alternative fuels, drop-in fuel has a substantial potential to repute itself as an efficient sustainable eco-friendly fuel in the near future.
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Pablo Domínguez de María John: INDUSTRIAL BIORENEWABLES:A Practical Viewpoint: Wiley & Sons.
Ram Sarup Singh, Ashok Pandey, Edgard Gnansounou: BIOFUELS- PRODUCTION AND FUTURE PERSPECTIVES, CRC Press.
Satinder Kaur Brar, Saurabh Jyoti Sarma, Kannan Pakshirajan : PLATFORM CHEMICAL BIOREFINERY-FUTURE GREEN CHEMISTRY, Elsevier.
Sergios Karatzos, James D. McMillan, Jack N. Saddle: Summary of IEA BIOENERGY TASK 39 REPORT-THE POTENTIAL AND CHALLENGES OF DROP-IN BIOFUELS, IEA Bioenergy.
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Global demand for fuel efficiency, environmental quality and energy security have elicited global attention towards liquid biofuels, such as bioethanol and biodiesel. Around the world, governments have introduced various policy measurements, mandatory fuel blending programmes, incentives for flex fuel vehicles and agricultural subsidies for the farmers.
In India, the government launched Ethanol Blended Petrol (EBP) programme in January 2013 for 5% ethanol blended petrol. The policy had significant focus on India’s opportunity to agricultural and industrial sectors with motive of boosting biofuel (bioethanol and biodiesel) usage and reducing the existing dependency on fossil fuel.
The Government of India initiated significant investments in improving storage and blending infrastructure. The National Policy on Biofuels has set a target of 20% blending of biofuel by 2017. However, India has managed to achieve only 5% by September 2016 due to certain technical, market and regulatory hurdles.
In India, sugarcane molasses is the major resource for bioethanol production and inconsistency of raw material supply holds the major liability for sluggish response to blending targets. Technically speaking, blend wall and transportation-storage are the major challenges towards the biofuel targets. Blending wall is the maximum percent of ethanol that can be blended to fuel without decreasing the fuel efficiency.
Various vehicles are adaptable to various blending ratio based on the flexibility of engines. The technology for the engine modification for flex fuel is not new but making the engines available in India along with the supply chain and calibrating the engine for Indian conditions is the halting phase. The commonly used motor vehicles in the country are not effectual with flex fuel.
Sugarcane molasses is the most common feedstock for bioethanol production in India
Ethanol being a highly flammable liquid marks obligatory safety and risk assessment measures during all phases of production, storage and transportation. The non-uniform distribution of raw material throughout the country, demands a compulsory transportation and storage, especially inter-state movement, encountering diverse climatic and topographic conditions.
Major bioethanol consumers in India are potable liquor sector (45%), alcohol based chemical industry (40%), the rest for blending and other purposes. The yearly profit elevation in major sectors is a dare to an economical ethanol supply for Ethanol Blending Programme. Drastic fluctuation in pricing of sugar cane farming and sugar milling resulted to huge debt to farmers by mill owners. Gradually the farmers shifted from sugarcane cultivation other crops.
Regulatory and policy approaches on excise duty on storage and transportation of ethanol and pricing strategy of ethanol compared to crude oil are to be revised and implemented effectively. Diversifying the feedstocks (especially use of lignocellulosic biomass) and advanced technology for domestic ethanol production in blending sectors are to be fetched out from research laboratories to commercial scale. Above all the knowledge of economic and environmental benefits of biofuel like reduction in pollutants and import bills and more R&D into drop-in biofuels, need to be amplified for the common man.
Vehicles remain a huge global pollutant, pumping out 28.85Tg of CO2 in Maharashtra alone, according to a study by the Indian Institute for Science in Bangalore. However, vehicles cannot be discarded, as they form the lifeblood of the country’s towns and cities. Between electric vehicles and hybrids, work is being done to help rectify the situation by making use of green car fuel and technological advancements.
Emissions continue to be a huge issue, and there are two main options for helping to rectify that. The first is electric, which is seeing widespread adoption; and the second, biomass fuel, for more traditional vehicles. Between the two, excellent progress is being made, but there’s much more to be done.
How electric is helping
Electric cars are favoured heavily by the national authorities. A recent Times of India report outlined how the government is aiming for an all-electric vehicle fleet by 2030 and is pushing this through with up to US$16m of electric vehicle grants this year.
Green vehicles are obviously a great choice, improving in-city noise and air pollution whilst providing better vehicular safety to boot; a study by the USA’s MIT suggested that electric vehicles are all-around safer than combustion.
However, where EVs fall down to some extent is through the energy they use. As they are charged from the electricity grid, this means that the electricity is largely derived from fossil fuels – official statistics show that India is 44% powered by coal. Ultimately, however, this does mean that emissions are reduced. Fuel is only burned at one source, and oil refining isn’t done at all, which is another source of pollutants. However, as time goes on and the government’s energy policy changes, EVs will continue to be a great option.
The role of biofuels
Biofuels are seeing a huge growth in use – BP has reported that globally, ethanol production grew 3% in 2017. Biofuel is commonly a more favoured option by the big energy companies given the infrastructure often available already to them. While biofuel has been slow on the uptake in India, despite the massive potential available for production, there are now signs this is turning around with the construction of two US$790m biofuel facilities.
Biofuels are increasingly being used to power vehicles around the world
The big benefit of biofuel is that it will have a positive impact on combustion and electric vehicles. The Indian government has stated they intend to use biofuel alongside coal production, with as much as 10% of energy being created using biofuel. Therefore, despite not being emission-free, biofuel will provide a genuine green energy option to both types of eco-friendly vehicle.
Green car fuel is not entirely clean. The energy has to come from somewhere, and in India, this is usually from coal, gas, and oil. However, the increase in biofuel means that this energy will inevitably get cleaner, making green car fuel absolutely a reality.
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