Development of biofuels for a green future

In the context of fossil fuel sources are gradually depleted, production and use of biofuels has become a popular trend in the world. In Vietnam, the development of biofuel production and use has been implemented since 2018. However, in order for this fuel to be widely used to contribute to environmental protection, there are still many obstacles.Among the alternative energy sources currently in use (wind, solar and nuclear energy), bioenergy is an inevitable development trend, especially in agricultural countries and imported. fuel, due to its benefits: production technology is not too complicated, utilizing local raw materials, increasing agricultural economic efficiency, without changing engine structure as well as lower facilities Existing floors and competitive prices compared to gasoline.Increasing the use of biofuels is not only about protecting the environment but also contributing to the positive transformation of the lives of people in remote areas of the country.


I. INTRODUCTION
As we all know, the world economy has so far and can last for most of the 21st century, heavily dependent on fossil fuels, despite this resource, including crude oil, which is a very big and polluting agent, is entering the preparatory phase of exhaustion as the inevitable fate of all kinds of finite natural resources when fully exploited [1][2] [3].
In addition, the need to protect the living environment on earth is long-term clean as well as the need for economic development at a high speed and on a large scale, making global energy security increasingly threatened.important.Therefore, the task of finding alternative sources for fossil fuels has been set for nearly half a century and is becoming increasingly urgent [4] [5] [6].One of the ways to solve this task is to use biomass, ie materials of organic origin to directly burn, to produce heat or electricity, or convert into energy carriers gas or liquid fuel.
Ethanol C2H5OH is a colorless liquid, boiling at 78.30C and is a versatile organic solvent, can be produced from petroleum through ethylene hydration reaction (synthetic ethanol, not used for energy purposes.amount) or from biological materials (bioethanol, mainly used for energy purposes) [7] [8].Bioethanol is capable of completely replacing petroleum-derived gasoline, or it can be mixed with gasoline to produce bio-gasoline.Biogas is registered with the letter "E" with a number of percentages of blended bioethanol in the gasoline.On the market, we often encounter bio-petrol such as E5, E20, E95 ... ie bio-petrol contains 5%, 20%, 95% ethanol [9].Lower gasoline types E25 are used directly for conventional gasoline engines, Van  without modification or modification of the machine.Using this type of fuel has reduced the dependence on imported petroleum-based gasoline, and increased the octane index of gasoline, reduced the amount of toxic emissions but had to consume more fuel on the same road [10].
With gasoline higher than E25, the car must transform engine structure.On the market there are FFV vehicles, called flexible fuel vehicles, that meet the requirements for all types of bio-fuels.Butanol has the formula C4H9OH, that is, has the same OH function group as ethanol, but the number of CH2 groups is more than 3 times, so it belongs to strong alcohol.butanol is less or more difficult to mix with water than ethanol.Like ethanol, butanol is obtained through chemical synthesis called butanol synthesized, mainly used as an industrial solvent, but if obtained by biological pathways, it is called bio-butanol, used like fuel [11].Bio-butanol has many advantages over bioethanol, such as being easily dissolved in gasoline, machinery is less likely to be corroded due to its non-absorbent properties; Not soluble in water, so it is easy to distill to absolute purity; energy density is 25% higher than bioethanol, close to the energy density of gasoline made from petroleum; High octane index approximates the average octane index of gasoline (RON96), so when using, it is not necessary to convert conventional gasoline engines; There is much lower pressure than gasoline as well as bioethanol, so it is less likely to be lost due to evaporation during storage, transportation, distribution and safety when using [12].
Due to the above advantages, bio-butanol is currently considered the preferred choice as an alternative to petroleum-based gasoline.In addition, bio-ethanol and biobutanol were also chosen as fuel for fuel cells used in transportation instead of hydrogen, however, they had to use the hydrogen reformer in the car.To have hydrogen before supplying fuel cells [13].The amount of CO2 emitted by the battery in this case is the amount of CO2 in the atmosphere absorbed by the plant during the previous photosynthesis process, so it can be considered as a balance of CO2 in the environment, no additional emissions [14].
Traditional diesel is also known as DO oil, containing hydrocarbons in the kerosen and medium segments in the oil refining process, ie at boiling temperatures from 2000C to 350 0 C. The main use of diesel is to fuel the internal combustion engine with the combustion properties characterized by the ability to burn itself, expressed by cetane values [15] [16].The longer the hydrocarbon has the n-paraffin circuit, the higher the cetane value, whereas, aromatic hydrocarbons, many rounds have low cetane values.Hexadecan n-C16H34 has cetane values of 100 and alpha-methylnapthalen C11H10 has a cetan value of zero.
Diesel chemical trends of internal combustion engines are Development of biofuels for a green future Van Huong Dong, Danh Chan Nguyen Ho Chi Minh city University of Transport, Ho Chi Minh city, Vietnam based on the advantages of diesel compared to gasoline as greater capacity when using the same amount of fuel, diesel engine accelerates faster, diesel prices can be cheaper when oil prices crude too high and may reduce the content of toxic substances in the exhaust gas [17][18].Biodiesel is a diesel fuel produced from biological materials, with the main chemical component of methyl ester of fatty acids.Compared with traditional diesel, made from petroleum, biodiesel has many advantages in terms of environmental protection such as, low sulfur (2-11ppmS), easy to decompose by microbiology, reducing air pollution.In addition, they are more lubricant than petroleum diesel, so the engine life will be longer and the material is taken from agricultural products or waste, so it can be regenerated quickly, contributing to increase value, using redundant labor, barren land, reducing import costs in foreign currencies [19][20].Today, depending on the source of different materials that each country produces many different types of biodiesel, then mix with traditional diesel according to the ratio specified in product standards such as B5 (5% biodiesel, 95 % diesel oil), B10 (10% biodiesel, 90% diesel oil), B20 (20% biodiesel, 80% diesel oil) [21].The disadvantage of biodiesel compared to petroleum diesel is that, the lower the heat, the higher the freezing point, the harder it is to use in the cold or in the winter, not the complete alternative to oil because of the supply of raw materials.difficult, abundant but not big enough to meet the demand; high costs should have a support policy of the state, production equipment and infrastructure in distribution must be newly built, the legal system to use gasoline fuel biofuel is not available or incomplete.

II. BIOFUEL SOURCES
Biofuel is a fuel made directly or indirectly from organic materials -biomass, consisting of two main sources from plants and animal waste, not from fossil sources such as oil, coal.At present, biofuels account for about 20% of global energy consumption.Particularly there are some countries, the use of biofuels is even bigger, such as Germany, Brazil, India ..., these are the leading countries in proving the availability and superiority of biofuels [22].Because fossil energy reserves are declining rapidly, as well as their use which has many consequences for habitat, bioenergy is an inevitable development for the future [23].
Some typical types of biofuels that are widely known today include: bioethanol (bioetanol), biodiesel (biodiesel), green diesel (diesel), biological kerosene (biokerosen-or reactive fuel).biological forces), other biological alcohols (methanol, butanol), bio ether, biogas, syngas, solid biomass fuels.In fact, the two most important biofuels are bioetanol and biodiesel, because of the many properties they have: use for the two most common types of transport (gasoline and motor vehicles).Diesel engine has many properties similar to fossil fuels, but cleaner and cleaner; produced from abundant and renewable materials such as sugar, starch, animal and vegetable fats and oils ... [24] [25] Biofuels can exist in all three solid, liquid, and gas states, and are also divided into three generations.First-generation biofuels, also known as traditional biofuels, are made from products used in food (sugar, starch, cooking oil, animal fat ...); Second generation biofuels are produced from agricultural and forestry by-products (waste oil, rubber seed oil, straw, rice husk, organic waste ...); Third generation biofuels come from non-food sources (such as marine microalgae, jatropha ...) [26] [27].These types are easy to grow and produce very large oil yield.
Each generation of fuel has its own advantages and disadvantages, for example, the production of fuel from the first generation faces the problem of food security and lack of land; Second-generation fuel production does not encounter this disadvantage but the transition from biomass to product is more difficult; Third-generation fuel overcomes all these disadvantages, but the price is currently at a high level, so breakthrough developments are needed to successfully commercialize.
Worldwide, the main source of raw materials for biofuel production is agricultural products, oilseeds, algae, cellulose and a small part of fish fat and animal fat in general [28].In South Africa and in the US, biofuels are made from corn.In Western European countries and in the United States, soybean-produced diesel production increased at the time of the nutritional value of unfermented soybean products, questioned with many genetically modified soybean plants.can produce high yields but not yet allowed for human consumption and for livestock.The use of bio-gasoline is becoming a trend in many countries, especially Europe and America.Currently, some countries have forced to use biogasoline such as Australia, New Zealand, China, India, Brazil ...Even in Southeast Asia, the Philippines, Thailand are the leading countries in using Bio-gasoline for more than 10 years.Indonesia is currently required to use E3 gasoline, from 2020 using E5 gasoline and after 2025 will use E25 gasoline [29][30] [31].
In Thailand, the Philippines ... biofuels are produced from cassava, palm nuts, and coconut rice, while in Brazil produced from sugarcane and in Canada, from waste wood, sawdust and wood byproducts.The fast-growing Kudzu vine has been imported from Japan, a few decades ago, which has spread over American soil.Many wetlands in Canada and the United States have become the new home of a fast-growing European tree called Purple Loosestrife.
These plants have almost zero cultivation costs, but very large yields.Along with the biomass sources from algae, oil of the seedling pomace (jodropha, Jatropha) and other nuts other than food, cultivation does not have to compete with food production land as well as all kinds of waste from livestock farms, agricultural waste and fiber industry, waste from vegetables ... is a very rich and promising material source for biofuels [32].
The biggest obstacle is that these resources are very scattered, it is difficult for collectors without a proper logistics organization.If the price of oil continues at a longterm high, biofuels can replace part of petroleum fuel, without subsidizing the state and being able to compete with other fuels to go into the market in a sustainable way [33] [34]. A. Corn Not only are staples in many countries, corn is also a potential source of biofuels.Thanks to the high sugar content to produce ethanol, corn is the source of the large amount of ethanol used in the production of E85 fuel.To produce ethanol from corn, the manufacturer first separates corn to get lignin and cellulose, which contains high sugar content.Refined ethanol is often added as a smoke reducing admixture [36].However, ethanol can also be used as the main fuel.Not only food, corn can also be a fuel.In the US, corn ethanol is actually an effective alternative fuel for fossil fuels.However, using corn is not without drawbacks.The demand for irrigation using people's water for growing corn is increasing, the potential risk of domestic and production water sources.Moreover, many farmers are switching from growing crops to growing corn for ethanol production.It is this, which has become a burden for the agricultural sector.Because cultivation does not meet the demand for food, the price of food may be pulled up by the fuel market.

B. Soybean
Soybeans are considered one of the most versatile ingredients.Soybeans are also used to make crayons and inks while corn to produce ethanol, soybeans are the main raw material for biodiesel production.To produce biodiesel from soybeans, one needs to filter out the oil of this seed.Oil content in soybeans is quite high, about 20% of grain content.The oil after being filtered out will be mixed with a catalyst to remove glycerin, The remaining oil can be used directly as fuel for engine use.Biodiesel is also cleaner than conventional diesel, reducing the problem of dust and health effects.

C. Palm
Manufacturers use palm oil to make biodiesel.Palm trees are used in many fields.In the food sector, palm oil is also popular, especially in the US and Western consumers because of its low fat content.In addition, palm oil is also used as a fuel.Palm oil combined with diesel produces a biofuel that benefits the environment because palm oil produces organic mixtures that, when burned in the engine, do not increase the concentration of carbon dioxide (CO2).CO2 is absorbed by palm trees in the growth cycle, thereby helping to balance the amount of gas escaping when burning.However, the use of palm oil also leads to potential consequences.Humans destroy natural forests for palm plantation, causing the habitat of many plants and animals to be destroyed.Because orangutans like to eat young palm leaves, the palm growers hunt them mercilessly.The number of orangutans was also reduced.George Washington Carver listed a list showing more than three hundred effects of peanuts, including the effect of biofuel.However, like corn, using peanuts as fuel has an inadequate effect on food issues.While many regions still lack food, people use peanuts to produce fuel.Brazil is a pioneer in using ethanol as an alternative fuel.From 1970 to deal with the oil crisis, the Pro-alcohol national program was born.Initially mixing 5% ethanol in gasoline to increase octane value, today has mixed up to 25%.Brazilian transport vehicles can use gasoline, ethanol independently or use a mixture of gasoline and ethanol.In addition to 3 million ethanol cars, there are 17 million cars running 25% ethanol.There are also about 400 small aircraft using ethanol.Annual production of 13-14 million m3 of ethanol is used domestically and for export, equivalent to 200,000 barrels of oil per day.The country has over 6.5 million hectares of sugarcane land.Annual sugarcaneethanol industry has a turnover of over 8 billion USD.
In the US, the government has adopted many policies such as a $ 0.5 / galon tax reduction on biofuels; tax reduction after import; Small manufacturer support.As a result, in 2005, the US produced 15 million cubic meters of biofuels.Currently 30% of gasoline in the US is made of biofuel.The US government also facilitates industrial-scale agricultural development to focus on creating material areas that meet the requirements of biofuel production.
In Europe, many companies have studied the production of biodiesel from soybean oil, canola oil, sunflower oil.Britain, France, Germany, Spain, Austria and Denmark have invested heavily in Biofuel programs.
China is a big oil importer after the US, in 2004, imported nearly 100 million tons of crude oil.Currently, the country has about 24 million cars and is expected to have about 100 million cars by 2020, so the amount of fuel used is very large.So, for many years, there has been a development program to produce ethanol from cereals and 10% anhydrous ethanol into gasoline.Since 2002, pilot ethanol has been used in 5 cities: Zhengzhou, Luoyang, Indonesia, Henan Province, Harbin, East China, Heilongjiang Province.Currently 80% of the ethanol fuel fuel market share is used in Heilongjiang, Jilin, Liu Ning and Ha Nam provinces.By the end of 2005, 27 more cities in Shandong, Hubei, Jiangsu and Hebei provinces were required to use ethanol blended gasoline.The amount of petroleum used in the pilot areas accounts for 25% of the total national consumption of gasoline.According to the ethanol-blended gasoline development program in the Reform and Development Committee's five-year plan 2005, China will produce more than 1.1 million tons of ethanol per year.The world's largest ethanol production plant with a capacity of over 600,000 tons / year began operating in Shandong province.
India is obliged to use pilot gasoline containing 5% ethanol in 9 states and 4 sub-regions since January 1, 2003.The remaining states will use ethanol blended gasoline in the second phase.This decision represents the Indian Government 's efforts to reduce dependence on imported oil from abroad (1 million barrels per day) and benefit sugarcane industry (acreage of 4.6 million hectares of sugarcane).).
Thailand has set up a National Committee on Ethanol to direct its implementation, promoting the development of biofuels.The Royal Project to produce ethanol blended gasoline has been implemented since 1985 with the participation of universities, research institutes and enterprises.On December 26, 2000, the Thai government approved a strong promotion policy for the production and use of ethanol as an alternative fuel.For the biofuel production program, policies to increase sugarcane and cassava production for alcohol production have been issued.In the crop year 2002 -2003, Thailand has about 1 million hectares of sugarcane with about 60 million tons of sugarcane, 4 times more than Vietnam and 20 million tons of fresh cassava.Thailand is striving to use over 2.5 million m3 ethanol by 2015, accounting for 10% of the domestic fuel and oil use.
Malaysia and the Philippines are countries that have the strength in research and production of biodiesel from oil crops in Southeast Asia.Malaysia has successfully cooperated with Mitsubishi Research on palm oil biodiesel production and has sold products to Europe.Meanwhile, the Philippines has enacted the Biofuels Law on January 12, 2007.Accordingly, Philippine petrol and diesel will have to mix 1% of biofuels.This blending rate increased to 2-5% after 2 years and is expected to increase to 4% after 4 years)

IV. CONCLUSION
The uneven development across regions has led to the situation of migration from rural to urban areas with increasing speed.Along with the rapid urbanization and the increase in transportation, the air and urban environment have been seriously polluted, especially in large cities.The level of pollution in big cities is at an alarming level.Therefore, the use of biofuel in gasoline will contribute to improving the environmental pollution by reducing the generation of waste gases in traditional fuels such as CO, SO2, dust particles and CO2.In addition, the development of raw material areas for ethanol production (cassava, sugarcane, algae ...) also contributes to green vegetation which reduces the impact of floods and storms and erosion.Development of biofuels helps countries to be proactive, not dependent on the issue of fuel imports, especially in countries without oil and coal resources.At the same time, curb the increase in oil prices, stabilize the energy profile for the world.The development of biofuels on the basis of utilizing huge biomass resources and being produced from renewable sources will really be a priority option in terms of security.energy security for nations.
Hiong Dong and Danh Chan Nguyen are with Ho Chi Minh city University of Transport, Ho Chi Minh city, Vietnam.