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Advances in Biodiesel Research and Development and Strategies for Industrialization: With the development of the global economy, energy demand worldwide is increasing steadily. On the contrary, the world’s reserves of fossil fuels (coal, oil, natural gas, etc.) are gradually decreasing ； At the same time, environmental pollution caused by the exhaust gases emitted from the combustion of petrochemical energy products is also a major problem facing humanity. Therefore, developing renewable and environmentally friendly alternative fuels has become one of the most important tasks for humanity in the 21st century. Under these circumstances. Environmentally friendly, renewable biofuel technologies have emerged as a result. As a clean liquid biofuel that can replace petrochemical diesel, biodiesel holds great potential and broad market prospects. 1 Advantages of biodiesel Biodiesel refers to methyl or ethyl esters of long-chain fatty acids produced through the synthesis of renewable oil-based raw materials; it is an environmentally friendly fuel that can serve as a substitute for petrochemical diesel. It is also a new type of environmentally friendly energy source. The oil feedstocks used for producing biodiesel can be vegetable oils (such as soybean oil, cottonseed oil, rapeseed oil, rice bran oil, palm oil, etc.), animal fats, as well as waste edible oils. Biodiesel has advantages that petrochemical diesel cannot match. It has an extremely low sulfur content, low levels of aromatic hydrocarbons, a high oxygen content, a high cetane number, a high flash point, and minimal exhaust emissions ； In the exhaust gases released after biodiesel combustion, the levels of particulates, hydrocarbons, and carbon monoxide are low ； Furthermore, it is a substance that is non-toxic to both humans and animals, environmentally friendly to use, and has certain health benefits. Compared to other alternative fuels such as compressed natural gas and fuel ethanol, systems that use biodiesel require less investment; existing engines, fueling equipment, storage facilities, and maintenance equipment generally need no modifications ； At the same time, it can be used as fuel, or as an additive that can be mixed with regular diesel in any proportion. Issue 2, 2006: 2 Current Status of the Development and Utilization of Biodiesel at Home and Abroad 2.1 United States The United States was the first country to conduct research on biodiesel; specialized research institutions for biodiesel were established as early as the 1970s, with significant investment in human resources and resources. By the 1990s, two major issues – environmental protection and the depletion of oil resources – received increasing attention, and biodiesel, as a focal point in the research and development of new energy sources, attracted even greater focus. **Through policy incentives, biodiesel has quickly become a highlight of the new economic sector. In 1992, the U.S. Energy Policy Act stipulated that by the year 2000, 10% of engine fuel should be replaced with non-petroleum fuels, and by 2010 this proportion was to reach 30%. In 1999, former U.S. President Clinton signed a decree to develop biomass energy, under which biodiesel was listed as one of the key clean fuels to be developed and was granted tax exemptions. Currently, there are 4 manufacturers, with a total production capacity of 300,000 tons per day. The United States has invested significant research efforts in using biotechnology to develop oil crops. \"Biological microalgae\" are produced through biotechnology, resulting in a lipid content of 40% to 60%. **Subsidy policies are used to encourage the cultivation of biofuel crops, mainly grain and oil crops such as soybeans and wheat. In November 2001, the U.S. Department of Agriculture allocated $150 million in subsidies to ethanol producers to increase the use of ethanol and biodiesel. 2.2 Europe: In Europe, biodiesel is primarily produced from rapeseed oil, and many countries offer tax reductions or subsidy programs to enhance the competitiveness of biodiesel, thereby improving air quality and reducing oil imports. In 1988, the German company Nier developed biodiesel, a clean fuel produced from rapeseed oil as its raw material. German automakers are allowed to use biodiesel derived from rapeseed in the cars they produce; therefore, Germans commonly refer to biodiesel as “rapeseed methyl ester”. In Germany, the production capacity of biodiesel increased from 110,000 tons to 533,000 tons between 1995 and 2001. Germany currently has 8 biodiesel production plants, over 900 biodiesel fuel stations, and it is mandated that biodiesel be sold only on major traffic routes. France has 7 manufacturing plants with a total production capacity of 400,000 tons ； 9 in Italy, with a total production capacity of 330,000 tons ； 3 in Austria, with a total production capacity of 55,000 tons ； There are 2 companies in Belgium, with a total production capacity of 240,000 tons, and these manufacturing firms are eligible for tax exemptions. Some automobile manufacturers allow the use of biodiesel only in their car engines; factors such as tax incentives have all contributed to the development of biofuels. Bovine spongiform encephalopathy in Europe spurred the development of biodiesel production from animal fat. According to the newly released report on the European biodiesel market, in order to achieve the goals set out in the Kyoto Protocol (for which Europe is required to reduce its carbon oxide emissions by 8% between 2008 and 2012), the EU will introduce corresponding policies to facilitate a significant increase in biodiesel production. Currently, the EU’s goal for promoting biodiesel is to reach 3.5 million tons by 2005 and 8.3 million tons by 2010. It aims to achieve a ratio of biofuels replacing fossil fuels of 2% by 2005, 5.57% by 2010, and 20% by 2020. 2.3 Others ** Et began researching biodiesel in 1995, and in 1997 established an industrial-scale experimental facility to produce biodiesel using 259 L/day of frying oil as raw material. Currently, the production capacity of biodiesel is 400,000 t/year. Thailand’s plan to develop biodiesel was announced in July 2001; the Thai Petroleum Corporation pledged to purchase 70,000 tons of palm oil and 20,000 tons of coconut oil each year, along with tax incentives. Thailand’s first biodiesel production facility has been put into operation. 2.4 China’s progress in biodiesel: In recent years, our country has supported research and development efforts related to biodiesel, and has included biodiesel in relevant scientific and technological innovation programs. “The 11th Five-Year Development Plan calls for the development of various alternatives to oil, and identifies renewable biodiesel as the **direction for industrial development**. Some initial research results have been achieved in the production of biodiesel using plant oils such as rapeseed oil, soybean oil, and cottonseed oil, as well as their by-products, and waste cooking oil (or gutter oil, swill oil) as raw materials. In 2001, Hainan Zhenghe Bioenergy Company introduced Korean technology to build a biodiesel plant in Handan, Hebei, with an annual production capacity of 10,000 tons. On June 8, 2003, a biodiesel plant with an annual production capacity of 30,000 tons was put into operation by Sichuan Gushan Group at Hebei Gushan Oil Chemistry Co., Ltd. Production lines of a certain scale have also been established in provinces and cities such as Fujian and Beijing. However, these production lines currently use waste oil or vegetable oil residues to produce biodiesel. Hunan Haina Baichuan Bioengineering Company (Yiyang) is utilizing technology from Tsinghua University to carry out pilot production and expansion of biodiesel production. Hunan Tianyuan Bioclean Energy Company has signed an agreement to adopt technology from British company Leo Ltd. for the construction of a facility capable of producing 200,000 tons of biodiesel derived from wild beans per year. 3 Research Progress in Biodiesel Technology Biodiesel is a general term for vegetable diesel and animal diesel. The specific preparation methods include physical methods, chemical methods, physicochemical methods, and biological methods. 3.1 Physical methods 3.1.1 Direct mixing method In 1983, Amahs and others mixed degummed soybean oil with diesel fuel No. 2 in ratios of 1:1 and 1:2 respectively, and conducted tests for 600 hours in direct-injection turbine engines. The results showed that no gelation or mixture separation occurred in the 1:2 mixture, and the fuel viscosity was reduced; hence it could be used as a substitute fuel for agricultural machinery. Currently, countries generally use a mixture ratio of 5% to 30%, and its performance is very similar to that of petroleum diesel. 3.1.2 Microemulsion method: This method involves mixing vegetable oils with animal oils to create microemulsions, in order to address the issue of high viscosity associated with plant and animal oils. In 1982, Georing et al. prepared microemulsions using an ethanol-water solution and soybean oil, while Ziejewski et al. created emulsions using winterized sunflower oil, methanol, and 1-butanol. Neuma et al., utilizing surfactants (mainly soybean oil soaps, sodium dodecyl sulfate, and fatty acid ethanolamines), co-surfactants (mainly ethyl, propyl, and isopentyl alcohols), water, refined diesel, and soybean oil as raw materials, developed a microemulsion system that could serve as a substitute for diesel. 3.2 Chemical methods refer to those that involve chemical reactions; these include chemical cracking methods and chemically catalyzed synthesis methods. 3.2.1 Chemical cracking method: This method involves heating and cracking vegetable oils to produce biodiesel with properties similar to those of conventional diesel. Schwab and Pioch conducted explorations in this area respectively, achieving fairly satisfactory results. 3.2.2 Chemical synthesis method: Acid and base catalysts are used to facilitate the synthesis of biodiesel through esterification or transesterification reactions. Currently, biodiesel is primarily produced by the chemical transesterification method, which involves reacting animal and plant fats and oils with low-carbon alcohols such as methanol or ethanol in the presence of acid or alkaline catalysts to produce the corresponding fatty acid methyl esters or ethyl esters; biodiesel is then obtained after washing and drying. Methanol or ethanol can be reused in the production process; the production equipment is the same as that used in ordinary oil production, and a by-product of about 10%—glycerin—is generated during production. However, the chemical synthesis of biodiesel has the following disadvantages: high requirements for raw materials, complex processes, high energy consumption, dark color, the unsaturated fatty acids in fats being prone to degradation at high temperatures, difficulty in recovering the methyl ester products, and the generation of waste alkaline solutions during the production process. 3.3 Physicochemical methods, namely catalyst-free supercritical fluid technology. To address issues such as high costs, long reaction times, and the difficulty in separating the reaction products from the catalyst in transesterification reactions, a new process that does not use a catalyst has been developed. Issue 2, 2006, VIP Information http://www.cqvip.com Freedman et al. studied the transesterification reaction between soybean oil and methanol under heating conditions, conducted kinetic studies, and determined the characteristics of the reaction in the absence of a catalyst. With an alcohol-to-oil ratio of 21:1 and a reaction time of 10 hours at 23512, the mass fraction of the methyl ester exceeded 85% ； With an alcohol-to-oil ratio of 27:1 and a reaction time of 8 hours at 220°C, the mass fraction of the methyl ester reached 67%. It was also found that the conversion rates of diglycerides and triglycerides were significantly higher than those of monoglycerides; that is, in the absence of a catalyst, the first two steps of the three-step reaction proceeded rapidly, while the final step proceeded very slowly. Saka and Ku~liana proposed a supercritical method for producing biodiesel; the reaction takes place in a preheated batch reactor at a temperature of 350–400°C and a pressure of 45–65 MPa, with a feed ratio of rapeseed oil to methanol of 1:42. Studies have found that methanol treated under supercritical conditions can undergo transesterification with rapeseed oil in the absence of a catalyst, yielding higher yields compared to conventional catalytic processes. The reaction proceeds rapidly, and it eliminates the separation and purification steps required when using a catalyst, thereby making the transesterification process simpler, safer, and more efficient. However, its reaction conditions are too stringent, the requirements for equipment are high, the processing volume is low, and continuous production cannot be achieved; as a result, industrialization is difficult, and its application prospects are uncertain. 3.4 Biological methods include bioenzyme catalysis and genetic engineering methods. 3.4.1 Bioenzymatic catalysis: Biological catalysts, namely lipases, are used to catalyze the transesterification reaction between animal and plant oils and fatty alcohols, in order to produce the corresponding fatty acid methyl esters and ethyl esters. Enzymatic synthesis of biodiesel offers advantages such as mild reaction conditions, low alcohol usage, no pollutant emissions, and low requirements for the feedstock oil. Studies on ester exchange reactions catalyzed by biological enzymes have shown that lipase is an excellent catalyst for the ester exchange of alcohols with fatty acid glycerides. As a biological catalyst, enzymes, with their high catalytic efficiency, are attracting increasing attention. Currently, problems such as the difficulty in separating chemical catalysts and the high energy required can all be solved by using enzyme catalysts. For example, immobilized enzyme catalysts using porous kaolinite as a carrier not only have a longer lifespan and do not require frequent replacement compared to other catalysts, but also exhibit high activity and are easy to separate; they represent a new type of catalyst with excellent performance and low cost. Ban et al. carried out an enzymatic reaction using olive oil and oleic acid as raw materials, achieving a methyl ester content of 90% in the product. How to improve enzyme activity and prevent enzyme poisoning is key to bioenzyme catalysis. The Department of Biochemical Engineering at Beijing University of Chemical Technology approaches the issue from the perspective of an integrated energy-resource-environment system. Using inexpensive and renewable plant and animal oils such as rapeseed oil, rice bran oil, and fried waste oil, as well as low-carbon alcohols like ethanol produced through the fermentation of crops, it produces environmentally friendly biodiesel through bioenzyme transesterification or esterification. New methods for curing using lipase isooctyl esters, along with esterification process reactors, have been developed to produce biodiesel with high conversion rates. Regarding the enzymatic production of biodiesel, at present only a very small number of institutions in China, such as Tsinghua University and Beijing University of Chemical Technology, have carried out some exploratory research; there are still many difficult issues that need to be studied and resolved. ·Oil Engineering· 3.4.2 Genetic engineering construction method: Utilizing genetic engineering techniques to produce biodiesel within organisms. This method enables the methylation (ethylation) of fatty acids to occur within living organisms by altering the fatty acid biosynthesis pathway, thereby opening up a new technical approach for the production of biodiesel. The use of microalgae engineering and microalgae developed through genetic engineering to produce diesel opens up new technical approaches for biodiesel production. 4 The prospects and development strategies for the industrialization of biodiesel in our country. At present, the industrialization of biodiesel in our country is still in its infancy, and there is a significant gap compared to developed countries in the West. However, in our country, there are about 1,000 oil-bearing plants with an oil content of over 15%, and about 300 species with an oil content of over 20% ； China’s hybrid rapeseed varieties are at the world’s leading level, with the planting area of rapeseed and the total output of rapeseed seeds ranking first in the world ； At the same time, our country is a major consumer of edible oils; in 2000, the total consumption of edible oils was around 12 million tons, resulting in approximately 10%, or 1.2 million tons, of waste edible oil. If this waste is recycled, it can also be used as a raw material for biodiesel. It is evident that China has abundant raw material resources required for the development of its biodiesel industry. According to projections by relevant authorities, China’s oil demand will reach 450 million tons per year by 2020, while the country’s annual oil production is expected to be only around 200 million tons at that time, resulting in a gap of 250 million tons. Even if all the world’s oil export capacity were available for China, it would still be completely impossible to meet our needs. Biodiesel features low dynamic viscosity, a high flash point, a high cetane number, and a high oxygen content; it is free of aromatics, is easy to degrade, and is environmentally friendly, making it suitable as a substitute fuel for petroleum. It is evident that biodiesel has broad industrialization prospects. However, the current production cost of biodiesel is high, with raw material costs accounting for over 70% of the total production cost. Therefore, we should adopt the following strategies to promote the industrial development of biodiesel in our country. (1)**Adopt appropriate policies to stimulate the development of the biodiesel industry. At present, many countries **such as the United States, Germany, France, Denmark, Italy, Ireland, and Spain** have adopted corresponding tax reduction policies to provide support. Our country should also adopt corresponding tax reduction and exemption policies ； At the same time, **measures should be taken to enforce the use of biodiesel in sectors such as the military and** ； Furthermore, the government should strive to facilitate the sale of biodiesel in the gas station network. (2)** Enterprises should increase their financial investment to encourage research and development of biodiesel feedstock crops as well as the establishment of feedstock cultivation bases, in order to ensure a stable supply of biodiesel raw materials. First, marginal lands unsuitable for the cultivation of traditional crops are encouraged to grow oilseeds with high yields and high oil content ； Secondly, guide the development of biodiesel feedstock crops in the vast western region ； Third, make full use of our country’s extensive marine resources to develop bio-phytoplankton engineering. At the same time, it is necessary to establish a sound management mechanism and select an appropriate development model in order to achieve a path of integrated development involving the government, local communities, and enterprises, as well as industry, agriculture, and forestry. VIP Information http://www.cqvip.com – Oil Engineering·(3)**: Enterprises should promptly improve and establish quality standards for biodiesel in order to regulate the biodiesel market. (4) Carry out international cooperation to introduce advanced foreign technologies and funds. The development and utilization of biodiesel is a major focus at the international level today. We should seize this favorable opportunity, adhere to a combination of independent development and the introduction, adaptation, and absorption of external technologies, and purposefully and selectively introduce advanced technical processes as well as key equipment and funds, in order to develop China’s biodiesel industry from a high starting point.