Category Archives: Biofuels

Is Green Car Fuel A Reality?

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drop-in-biofuelsVehicles 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.

Also Read: Exploring the Rise of Green Energy Vehicles in Business

Resource Base for Second-Generation Biofuels

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Second-generation biofuels, also known as advanced biofuels, primarily includes cellulosic ethanol. The resource base for the production of second-generation biofuel are non-edible lignocellulosic biomass resources (such as leaves, stem and husk) which do not compete with food resources. The resource base for second-generation biofuels production is broadly divided into three categories – agricultural residues, forestry wastes and energy crops.

second-generation-biofuels

Agricultural Residues

Agricultural residues encompasses all agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. which come from cereals (rice, wheat, maize or corn, sorghum, barley, millet), cotton, groundnut, jute, legumes (tomato, bean, soy) coffee, cacao, tea, fruits (banana, mango, coco, cashew) and palm oil.

Rice produces both straw and rice husks at the processing plant which can be conveniently and easily converted into energy. Significant quantities of biomass remain in the fields in the form of cob when maize is harvested which can be converted into energy.

Sugarcane harvesting leads to harvest residues in the fields while processing produces fibrous bagasse, both of which are good sources of energy. Harvesting and processing of coconuts produces quantities of shell and fibre that can be utilised while peanuts leave shells. All these lignocellulosic materials can be converted into biofuels by a wide range of technologies.

Forestry Biomass

Forest harvesting is a major source of biomass energy. Harvesting in forests may occur as thinning in young stands, or cutting in older stands for timber or pulp that also yields tops and branches usable for production of cellulosic ethanol.

Biomass harvesting operations usually remove only 25 to 50 percent of the volume, leaving the residues available as biomass for energy. Stands damaged by insects, disease or fire are additional sources of biomass. Forest residues normally have low density and fuel values that keep transport costs high, and so it is economical to reduce the biomass density in the forest itself.

Energy Crops

Energy crops are non-food crops which provide an additional potential source of feedstock for the production of second-generation biofuels. Corn and soybeans are considered as the first-generation energy crops as these crops can be also used as the food crops. Second-generation energy crops are grouped into grassy (herbaceous or forage) and woody (tree) energy crops.

Grassy energy crops or perennial forage crops mainly include switchgrass and miscanthus. Switchgrass is the most commonly used feedstock because it requires relatively low water and nutrients, and has positive environmental impact and adaptability to low-quality land. Miscanthus is a grass mainly found in Asia and is a popular feedstock for second-generation biofuel production in Europe.

Woody energy crops mainly consists of fast-growing tree species like poplar, willow, and eucalyptus. The most important attributes of these class species are the low level of input required when compared with annual crops. In short, dedicated energy crops as feedstock are less demanding in terms of input, helpful in reducing soil erosion and useful in improving soil properties.

Biofuels from Lignocellulosic Biomass

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Lignocellulosic biomass consists of a variety of materials with distinctive physical and chemical characteristics. It is the non-starch based fibrous part of plant material.

Lignocellulose is a generic term for describing the main constituents in most plants, namely cellulose, hemicelluloses, and lignin. Lignocellulose is a complex matrix, comprising many different polysaccharides, phenolic polymers and proteins. Cellulose, the major component of cell walls of land plants, is a glucan polysaccharide containing large reservoirs of energy that provide real potential for conversion into biofuels.

Straw_Bales

First-generation biofuels (produced primarily from food crops such as grains, sugar beet and oil seeds) are limited in their ability to achieve targets for oil-product substitution, climate change mitigation, and economic growth. Their sustainable production is under scanner, as is the possibility of creating undue competition for land and water used for food and fibre production.

The cumulative impacts of these concerns have increased the interest in developing biofuels produced from non-food biomass. Feedstocks from lignocellulosic materials include cereal straw, bagasse, forest residues, and purpose-grown energy crops such as vegetative grasses and short rotation forests. These second-generation biofuels could avoid many of the concerns facing first-generation biofuels and potentially offer greater cost reduction potential in the longer term.

The largest potential feedstock for biofuels is lignocellulosic biomass, 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 biomass resources do not interfere with food security. Moreover, bioethanol is very important for both rural and urban areas in terms of energy security reason, environmental concern, employment opportunities, agricultural development, foreign exchange saving, socioeconomic issues etc.

Lignocellulosic biomass consists mainly of lignin and the polysaccharides cellulose and hemicellulose. Compared with the production of ethanol from first-generation feedstocks, the use of lignocellulosic biomass is more complicated because the polysaccharides are more stable and the pentose sugars are not readily fermentable by Saccharomyces cerevisiae. 

In order to convert lignocellulosic biomass to biofuels the polysaccharides must first be hydrolysed, or broken down, into simple sugars using either acid or enzymes. Several biotechnology-based approaches are being used to overcome such problems, including the development of strains of Saccharomyces cerevisiae that can ferment pentose sugars, the use of alternative yeast species that naturally ferment pentose sugars, and the engineering of enzymes that are able to break down cellulose and hemicellulose into simple sugars.

Lignocellulosic biomass processing pilot plants have been established in the EU, in Denmark, Spain and Sweden. The world’s largest demonstration facility of lignocellulose ethanol (from wheat, barley straw and corn stover), with a capacity of 2.5 Ml, was first established by Iogen Corporation in Ottawa, Canada. Many other processing facilities are now in operation or planning throughout the world.

Economically, lignocellulosic biomass has an advantage over other agriculturally important biofuels feedstock such as corn starch, soybeans, and sugar cane, because it can be produced quickly and at significantly lower cost than food crops.

Lignocellulosic biomass is an important component of the major food crops; it is the non-edible portion of the plant, which is currently underutilized, but could be used for biofuel production. In short, biofuels from lignocellulosic biomass holds the key to supplying society’s basic needs without impacting the nation’s food supply.

Biochemical Method for Ethanol Production

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Ethanol from lignocellulosic biomass is produced mainly via biochemical route. The three major steps involved in the biochemical method for ethanol production 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.

Bioethanol-production-process

Pretreated biomass can directly be converted to ethanol by using the process called simultaneous saccharification and cofermentation (SSCF). Pretreatment is a critical step which enhances the enzymatic hydrolysis of biomass.

Basically, it alters the physical and chemical properties of biomass and improves the enzyme access and effectiveness which may also lead to a change in crystallinity and degree of polymerization of cellulose. The internal surface area and pore volume of pretreated biomass are increased which facilitates substantial improvement in accessibility of enzymes. The process also helps in enhancing the rate and yield of monomeric sugars during enzymatic hydrolysis steps.

Pretreatment methods can be broadly classified into four groups – physical, chemical, physio-chemical and biological. Physical pretreatment processes employ the mechanical comminution or irradiation processes to change only the physical characteristics of biomass. The physio-chemical process utilizes steam or steam and gases, like SO2 and CO2. The chemical processes employs acids (H2SO4, HCl, organic acids etc) or alkalis (NaOH, Na2CO3, Ca(OH)2, NH3 etc).

The acid treatment typically shows the selectivity towards hydrolyzing the hemicelluloses components, whereas alkalis have better selectivity for the lignin. The fractionation of biomass components after such processes help in improving the enzymes accessibility which is also important to the efficient utilization of enzymes.

The pretreated biomass is subjected to enzymatic hydrolysis using cellulase enzymes to convert the cellulose to fermentable sugars. Cellulase refers to a class of enzymes produced chiefly by fungi and bacteria which catalyzes the hydrolysis of cellulose by attacking the glycosidic linkages. Cellulase is mixture of mainly three different functional protein groups: exo-glucanase (Exo-G), endo-glucanase(Endo-G) and ?-glucosidase (?-G).

The functional proteins work synergistically in hydrolyzing the cellulose into the glucose. These sugars are further fermented using microorganism and are converted to ethanol. The microorganisms are selected based on their efficiency for ethanol productivity and higher product and inhibitors tolerance. Yeast Saccharomyces cerevisiae is used commercially to produce the ethanol from starch and sucrose.

Escherichia coli strain has also been developed recently for ethanol production by the first successful application of metabolic engineering. E. coli can consume variety of sugars and does not require the complex growth media but has very narrow operable range of pH. E. coli has higher optimal temperature than other known strains of bacteria.

Lower GHG emissions and empowerment of rural economy are major benefits associated with bioethanol

The major cost components in bioethanol production from lignocellulosic biomass are the pretreatment and the enzymatic hydrolysis steps. In fact, these two process are someway interrelated too where an efficient pretreatment strategy can save substantial enzyme consumption.

Pretreatment step can also affect the cost of other operations such as size reduction prior to pretreatment. Therefore, optimization of these two important steps, which collectively contributes about 70% of the total processing cost, are the major challenges in the commercialization of bioethanol from 2nd generation feedstock.

Enzyme cost is the prime concern in full scale commercialization. The trend in enzyme cost is encouraging because of enormous research focus in this area and the cost is expected to go downward in future, which will make bioethanol an attractive option considering the benefits derived its lower greenhouse gas emissions and the empowerment of rural economy.

Breaking Down the Process of Biofuel Production

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Biofuels are renewable and sustainable forms of energy. They can reduce greenhouse emissions by almost 30%, which means that although they do release carbon dioxide into the atmosphere, they do so in a very limited manner.

With the aim of building a green new world, and eliminating the need for fossil fuel and other traditional energy sources, people are now turning towards biofuel to meet their daily needs. Thus, we see biofuel being used for transportation in many countries. It’s also being used to generate electricity. The rural areas in many underdeveloped and developing countries will use biofuel for their cooking purposes as well. All in all, this particular fuel has diverse uses.

Biofuel is produced from biomass, which itself is treated as a clean energy source. We can produce biofuel from biomass through a series of steps. These steps can be performed even in our houses if we have the right materials. A quick overview of the whole biofuel production process is described below.

biofuel-production

1. Filtration

The purpose of the filtration process is to get rid of the unnecessary particles from the biomass. In this step, we take the waste vegetable oil and then heat it to a certain degree. Once the liquid has been heated, the waste particles will automatically separate themselves from the main mixture. Afterward, we just have to filter it with a regular filter paper.

2. Water removal

Next, we need to remove water from the residual gangue. If the water is allowed to stay in the mixture, it’ll end up delaying the overall process. By removing all the water, we can make the reaction move a lot faster. The easiest way to remove water from the mixture is by heating it steady at 212 degrees F for some time.

3. Titration

Titration is conducted on the mixture to determine the amount of chemical catalyst (like lye) that will be needed. The catalyst is a key component in any chemical reaction. It pretty much determines how fast and how much of a product we’re going to receive. Thus, this step is very important in the biofuel manufacturing process.

4. Sodium methoxide preparation

In this step, we take methanol (18-20% of the waste vegetable oil) and mix it with sodium hydroxide. This gives us sodium methoxide, which is also used as a catalyst in the reaction. It helps perform synthesis reactions on the reagents and facilitates the overall reaction process. Sodium methoxide is a key ingredient in this manufacturing process. It’s considered to be a standard substance used to accelerate the reaction, and yield better results.

5. Mixing and heating

Next, we heat the residue between 120-130 degrees F. Afterward, we mix it properly. This process aims to evenly distribute the mixture. This will help the mixture to settle down later on, and cool off, after which we can begin the extraction process. In a way, the mixing and heating stage can be seen as the final preparation before extraction.

biofuel-production

6. Setting

Once the mixing is completed, the liquid is allowed to cool and settle down, after which we can extract the final product, i.e. the biofuel.

7. Separation

After the liquid has cooled, the biofuel can be extracted from the top of the mixture. It’ll be found floating on top, like oil in water. To get the biofuel, we’ll have to remove the glycerin underneath it. This can be done by simply draining it out from the bottom, and keeping the fuel afloat. The biofuel is finally ready.

The whole process described above is for a small-scale operation. However, it can be scaled up as needed, given that you have the right tools, ingredients, and setup.

It should also be noted that chemical catalysts (such as lye) are used in the manufacturing process as well. Recently, however, scientists and researchers are looking into the use of ultrasonics as additional catalysts. According to recent observations, a combination of chemicals and ultrasonics can lead to a higher yield of fuel, and reduce the overall processing time. This also leads to better utilization of biomass.

Companies such as Coltraco (https://coltraco.com/) are now using ultrasonic systems and technology in a wide variety of fields, one of which is the renewable energy industry. And while the technology’s use in other fields has gained more traction in recent times, it shouldn’t be long before it’s used in biofuel manufacturing, as well as in other renewable energy sectors, in full swing.

How Biofuel is Impacting Our World in 2023

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The world is changing. We’ve come a long way from the days when the only option for fuel was the fossil-fueled version. However, more strides can be made. In 2021, fossil fuels still accounted for 79% of U.S. energy consumption. While it’s hard to leave behind our dependence on it, fossil fuels must eventually go, and renewable energy sources must take their place.

In 2021, renewable energy contributed only 12% to the total U.S. energy consumption. Of course, that rate is gradually growing upward. Now, you can find renewable fuels and even hybrid engines that combine both traditional petroleum-based fuels and biofuels. What are these biofuels?

how biofuels is impacting the world

The best way to explain them is by looking at how they work and what they do for our planet’s future. Biofuel is one of the renewable energy sources that contributed to the U.S. energy consumption in 2021. Of all the other renewable sources, biofuel was the joint-second most popular one, alongside hydroelectric energy. As time progresses, we’ll see this energy source contributing more to our energy sector and the environment.

Having said all that, here are a few ways biofuel is impacting our world today and will continue impacting it in 2023 and beyond.

Producing Biofuels is Better for the Environment

Biofuels are a renewable, clean-burning source of energy that can be used to replace fossil fuels. When you burn biofuel, you aren’t releasing greenhouse gasses into the air. In fact, when considering the life-cycle carbon footprint of biofuels—from cultivation through production and use—they actually emit fewer greenhouse gasses than petroleum or other fossil fuels.

Diesel engines and diesel are used in trucks and heavy equipment like tractors and bulldozers, buses, trains, and ships. Biofuel can be used as an alternative fuel instead of diesel fuel in these vehicles without requiring any modifications to them because it is chemically compatible with petroleum diesel.

Many colleges and universities across the world are heavily invested in research involving biofuels. Even courses are specifically designed to involve their students in either generic or extensive ways. Studying Strayer University’s notebooks will help you realize just that. Students use these notebooks to gain a better understanding of their biology and chemistry lessons. They also use them for research down the line. A quick look at these notebooks will reveal just how invested these universities are in biofuel and other green energy alternatives.

Biofuel is Less Expensive Than Other Petroleum Alternatives

When it comes to cost, biofuels have a distinct advantage over petroleum alternatives. On top of these high prices, consumers are also paying high taxes on their fuel purchases due to their carbon emissions being harmful to the environment and society at large.

Coal is another fossil fuel whose prices fluctuate depending on how much demand there is for it from utilities across North America. Coal-produced energy is also costly. Thus, biofuel needs to be embraced by the masses if they want to limit their spending on fossil fuels.

Biofuel Consumption Increases the Gross Domestic Product

The more fuel you use, the more money you spend on that fuel. When you buy biofuel, your purchase creates jobs in areas like agriculture, transportation, and distribution. This creates a ripple effect throughout your local economy as well as in other sectors around the world.

In addition to this direct benefit, governments also benefit from rising GDPs because they can collect taxes on these sales. Consumers will also have more disposable income to spend on goods and services outside of their normal budgets, increasing economic activity worldwide.

Biofuel Can be Better for Your Engine’s Lifespan

In addition to being better for the environment, biofuel can also be better for your engine’s lifespan. The reason is that the different chemicals in biofuels react differently with your engine. As a result, you may need a different blend of biofuel than your car is used to running on. This means that you should consult with an auto mechanic before using any kind of alternative fuel in your vehicle.

Biofuels Are More Efficient Than Gasoline and Diesel

Biofuels are more efficient than petroleum fuels. They have a higher energy density than conventional gasoline and diesel, which means you can get more power out of a smaller amount of fuel. This is especially important for cars that rely on internal combustion engines (ICE), which are the standard vehicle in many parts of the world.

impact of biofuels on air quality

Biofuels are increasingly being used to power vehicles around the world

The majority of ICEs cannot burn biofuel blends directly. They require some kind of modification first. However, they can use it by converting existing gasoline or diesel engines with special hardware.

Biofuels Improve Air Quality in Urban Areas

Biofuels reduce the amount of particulate matter (PM), carbon monoxide (CO), and nitrogen oxides (NOx) in urban areas. PM is a collection of solid particles that get into the air and cause health problems like lung cancer and asthma. CO causes smog that can irritate your eyes and make it hard to breathe normally. NOx gasses contribute to the formation of ozone, another pollutant that is harmful to human health.

The concentration of all these gasses and particles in biofuel emissions is low. Thus, vehicles running on biofuel do not heavily harm the air quality.

Bottom Line

Biofuel is the future of clean energy. The sooner we understand this fact and accept biofuel, the better it is for us and this planet.

Everything You Need to Know About Biomass Energy Systems

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Biomass is a versatile energy source that can be used for production of heat, power, transport fuels and biomaterials, apart from making a significant contribution to climate change mitigation. Currently, biomass-driven combined heat and power, co-firing, and combustion plants provide reliable, efficient, and clean power and heat.

Feedstock for biomass energy plants can include residues from agriculture, forestry, wood processing, and food processing industries, municipal solid wastes, industrial wastes and biomass produced from degraded and marginal lands.

biomass-energy-systems

The terms biomass energy, bioenergy and biofuels cover any energy products derived from plant or animal or organic material. The increasing interest in biomass energy and biofuels has been the result of the following associated benefits:

  • Potential to reduce GHG emissions.
  • Energy security benefits.
  • Substitution for diminishing global oil supplies.
  • Potential impacts on waste management strategy.
  • Capacity to convert a wide variety of wastes into clean energy.
  • Technological advancement in thermal and biochemical processes for waste-to-energy transformation.

Biomass can play the pivotal role in production of carbon-neutral fuels of high quality as well as providing feedstock for various industries. This is a unique property of biomass compared to other renewable energies and which makes biomass a prime alternative to the use of fossil fuels. Performance of biomass-based systems for heat and power generation has been already proved in many situations on commercial as well as domestic scales.

Biomass energy systems have the potential to address many environmental issues, especially global warming and greenhouse gases emissions, and foster sustainable development among poor communities. Biomass fuel sources are readily available in rural and urban areas of all countries. Biomass-based industries can provide appreciable employment opportunities and promote biomass re-growth through sustainable land management practices.

The negative aspects of traditional biomass utilization in developing countries can be mitigated by promotion of modern biomass-to-energy technologies which provide solid, liquid and gaseous fuels as well as electricity as shown. Biomass wastes can be transformed into clean and efficient energy by biochemical as well as thermochemical technologies.

The most common technique for producing both heat and electrical energy from biomass wastes is direct combustion. Thermal efficiencies as high as 80 – 90% can be achieved by advanced gasification technology with greatly reduced atmospheric emissions. Combined heat and power (CHP) systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity.

Biochemical processes, like anaerobic digestion and sanitary landfills, can also produce clean energy in the form of biogas and producer gas which can be converted to power and heat using a gas engine.

In addition, biomass wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels. Cellulosic ethanol can be produced from grasses, wood chips and agricultural residues by biochemical route using heat, pressure, chemicals and enzymes to unlock the sugars in lignocellulosic biomass. Algal biomass is also emerging as a good source of energy because it can serve as natural source of oil, which conventional refineries can transform into jet fuel or diesel fuel.

Things You Should Know About Biofuels

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Biofuels refers to liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. A variety of fuels can be produced from biomass resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The biomass feedstock for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues.

Biodiesel

The agricultural resources include grains used for biofuels production, animal manures and residues, and crop residues derived primarily from corn and small grains (e.g., wheat straw). A variety of regionally significant crops, such as cotton, sugarcane, rice, and fruit and nut orchards can also be a source of crop residues.

The forest resources include residues produced during the harvesting of forest products, fuelwood extracted from forestlands, residues generated at primary forest product processing mills, and forest resources that could become available through initiatives to reduce fire hazards and improve forest health.

Municipal and urban wood residues are widely available and include a variety of materials — yard and tree trimmings, land-clearing wood residues, wooden pallets, organic wastes, packaging materials, and construction and demolition debris.

Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking. Biofuel industries are expanding in Europe, Asia and the Americas. Biofuels are generally considered as offering many priorities, including sustainability, reduction of greenhouse gas emissions, regional development, social structure and agriculture, and security of supply.

First-generation biofuels are made from sugar, starch, vegetable oil, or animal fats using conventional technology. The basic feedstocks for the production of first-generation biofuels come from agriculture and food processing. The most common first-generation biofuels are:

  • Biodiesel: extraction with or without esterification of vegetable oils from seeds of plants like soybean, oil palm, oilseed rape and sunflower or residues including animal fats derived from rendering applied as fuel in diesel engines
  • Bioethanol: fermentation of simple sugars from sugar crops like sugarcane or from starch crops like maize and wheat applied as fuel in petrol engines
  • Bio-oil: thermochemical conversion of biomass. A process still in the development phase
  • Biogas: anaerobic fermentation or organic waste, animal manures, crop residues an energy crops applied as fuel in engines suitable for compressed natural gas.

First-generation biofuels can be used in low-percentage blends with conventional fuels in most vehicles and can be distributed through existing infrastructure. Some diesel vehicles can run on 100 % biodiesel, and ‘flex-fuel’ vehicles are already available in many countries around the world.

Bioethanol-production-process

Second-generation biofuels are derived from non-food feedstock including lignocellulosic biomass like crop residues or wood. Two transformative technologies are under development.

  • Biochemical: modification of the bioethanol fermentation process including a pre-treatment procedure
  • Thermochemical: modification of the bio-oil process to produce syngas and methanol, Fisher-Tropsch diesel or dimethyl ether (DME).

Advanced conversion technologies are needed for a second-generation biofuels. The second generation technologies use a wider range of biomass resources – agriculture, forestry and waste materials. One of the most promising second-generation biofuel technologies – ligno-cellulosic processing (e. g. from forest materials) – is already well advanced. Pilot plants have been established in the EU, in Denmark, Spain and Sweden.

Third-generation biofuels may include production of bio-based hydrogen for use in fuel cell vehicles, e.g. Algae fuel, also called oilgae. Algae are low-input, high-yield feedstock to produce biofuels.

Things You Should Know About Algaculture

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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, using land that is not suitable for agriculture.

Algae holds enormous potential to provide a non-food, high-yield, non-arable land use source of biodiesel, ethanol and hydrogen fuels. Microalgae are the fastest growing photosynthesizing organism capable of completing an entire growing cycle every few days. Up to 50% of algae’s weight is comprised of oil, compared with, for example, oil palm which yields just about 20% of its weight in oil.

Algaculture (farming of algae) can be a route to making vegetable oils, biodiesel, bioethanol and other biofuels. Microalgae are one-celled, photosynthetic microorganisms that are abundant in fresh water, brackish water, and marine environments everywhere on earth. The potential for commercial algae production is expected to come from growth in translucent tubes or containers called photo bioreactors or open ocean algae bloom harvesting. The other advantages of algal systems include:

  • carbon capture from smokestacks to increase algae growth rates
  • processing of algae biomass through gasification to produce syngas
  • growing carbohydrate rich algae strains for cellulosic ethanol
  • using waste streams from municipalities as water sources

Algae have certain qualities that make the organism an attractive option for biodiesel production. Unlike corn-based biodiesel which competes with food crops for land resources, algae-based production methods, such as algae ponds or photobioreactors, would “complement, rather than compete” with other biomass-based fuels. Unlike corn or other biodiesel crops, algae do not require significant inputs of carbon intensive fertilizers.  Some algae species can even grow in waters that contain a large amount of salt, which means that algae-based fuel production need not place a large burden on freshwater supplies.

Several companies and government agencies are funding efforts to reduce capital and operating costs and make algae fuel production commercially viable. Companies such as Sapphire Energy and Bio Solar Cellsare using genetic engineering to make algae fuel production more efficient. According to Klein Lankhorst of Bio Solar Cells, genetic engineering could vastly improve algae fuel efficiency as algae can be modified to only build short carbon chains instead of long chains of carbohydrates.

Sapphire Energy also uses chemically induced mutations to produce algae suitable for use as a crop. Some commercial interests into large-scale algal-cultivation systems are looking to tie in to existing infrastructures, such as cement factories, coal power plants, or sewage treatment facilities. This approach changes wastes into resources to provide the raw materials, CO2 and nutrients, for the system.

Ethanol Production from Lignocellulosic Biomass

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Cellulosic ethanol technology is one of the most commonly discussed second-generation biofuel technologies worldwide. Cellulosic biofuels are derived from the cellulose in plants, some of which are being developed specifically as “energy” crops rather than for food production. These include perennial grasses and trees, such as switchgrass and Miscanthus. Crop residues, in the form of stems and leaves, represent another substantial source of cellulosic biomass.

Bioethanol_Pump

The largest potential feedstock for ethanol is lignocellulosic biomass, which includes materials such as agricultural residues (corn stover, crop straws, husks 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. Lignocellulosic biomass feedstocks do not interfere with food security and are important for both rural and urban areas in terms of energy security reason, environmental concern, employment opportunities, agricultural development, foreign exchange saving, socioeconomic issues etc.

Production of Ethanol

The production of ethanol from lignocellulosic biomass can be achieved through two different processing routes. They are:

  • Biochemical – in which enzymes and other micro-organisms are used to convert cellulose and hemicellulose components of the feedstocks to sugars prior to their fermentation to produce ethanol;
  • Thermochemical – where pyrolysis/gasification technologies produce a synthesis gas (CO + H2) from which a wide range of long carbon chain biofuels, such as synthetic diesel or aviation fuel, can be reformed.

Lignocellulosic biomass consists mainly of lignin and the polysaccharides cellulose and hemicellulose. Compared with the production of ethanol from first-generation feedstocks, the use of lignocellulosic biomass is more complicated because the polysaccharides are more stable and the pentose sugars are not readily fermentable by Saccharomyces cerevisiae. 

In order to convert lignocellulosic biomass to biofuels the polysaccharides must first be hydrolysed, or broken down, into simple sugars using either acid or enzymes. Several biotechnology-based approaches are being used to overcome such problems, including the development of strains of Saccharomyces cerevisiae that can ferment pentose sugars, the use of alternative yeast species that naturally ferment pentose sugars, and the engineering of enzymes that are able to break down cellulose and hemicellulose into simple sugars.

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.

Pretreated biomass can directly be converted to ethanol by using the process called simultaneous saccharification and cofermentation (SSCF).  Pretreatment is a critical step which enhances the enzymatic hydrolysis of biomass. Basically, it alters the physical and chemical properties of biomass and improves the enzyme access and effectiveness which may also lead to a change in crystallinity and degree of polymerization of cellulose.

The internal surface area and pore volume of pretreated biomass are increased which facilitates substantial improvement in accessibility of enzymes. The process also helps in enhancing the rate and yield of monomeric sugars during enzymatic hydrolysis steps.

Pretreatment of Lignocellulosic Biomass

Pretreatment methods can be broadly classified into four groups – physical, chemical, physio-chemical and biological. Physical pretreatment processes employ the mechanical comminution or irradiation processes to change only the physical characteristics of biomass. The physio-chemical process utilizes steam or steam and gases, like SO2 and CO2.

The chemical processes employs acids (H2SO4, HCl, organic acids etc) or alkalis (NaOH, Na2CO3, Ca(OH)2, NH3 etc). The acid treatment typically shows the selectivity towards hydrolyzing the hemicelluloses components, whereas alkalis have better selectivity for the lignin. The fractionation of biomass components after such processes help in improving the enzymes accessibility which is also important to the efficient utilization of enzymes.

Conclusions

The major cost components in bioethanol production from lignocellulosic biomass are the pretreatment and the enzymatic hydrolysis steps. In fact, these two process are someway interrelated too where an efficient pretreatment strategy can save substantial enzyme consumption. Pretreatment step can also affect the cost of other operations such as size reduction prior to pretreatment.

Therefore, optimization of these two important steps, which collectively contributes about 70% of the total processing cost, are the major challenges in the commercialization of bioethanol from 2nd generation biofuel feedstock.