With the increasingly serious environmental pollution and the increasingly urgent energy crisis, people are urgently in need of a clean, environmentally friendly and renewable energy. The renewability and cleanliness of biodiesel have attracted worldwide attention. The production and application status, development trend of biodiesel at home and abroad and the significance of developing biodiesel in China were summarized. The research progress of biodiesel production methods was introduced in detail. The transesterification reaction was mainly introduced. The existing problems of biodiesel were analyzed.
Oil is an extremely important strategic material for national economic and social development and national defense construction. However, in recent years, oil supply is in short supply and oil prices remain high. From the perspective of environmental protection and resource strategy, countries are actively exploring the development of renewable, clean and environmentally friendly energy sources. As a substitute of high quality diesel oil, biodiesel has important strategic significance for sustainable economic development, promoting energy substitution, alleviating environmental pressure and controlling urban air pollution. China is a country with a shortage of petroleum resources and a slow growth of its production capacity. However, with the improvement of living standards, the demand for oil has increased sharply, and the supply gap has become larger and larger. In 2005, China produced 118.5 billion tons of crude oil, imported 112.7 billion tons of crude oil, and imported 17.42 million tons of refined oil. The degree of dependence on foreign oil has reached 42.19%. This situation not only brings great pressure to the oil supply, but also endangers the national energy security. On the other hand, China’s environmental situation is not optimistic, and the pollution caused by the use of energy is an important aspect. Therefore, it is of great significance to develop biodiesel in China.
1 Application of Biodiesel at Home and Abroad
1–1–1 the United States
The United States is one of the first countries to study biodiesel. Soybean oil is the main raw material. The commercial application of biodiesel in the United States began in the early 1990s, but it did not take shape until recent years. It has become the fastest growing alternative fuel in the country. Its output has soared from 500,000 gallons in 1999 to 5,000 gallons in 2000. At present, there are four manufacturers in the United States, with a total production capacity of 300,000 t/a [2], and the production capacity of biodiesel in the United States is expected to reach 1.15 million t/a by 2011. In the development of diesel oil production in the United States, breakthroughs have been made in the rationalization of production costs, the selection of suitable raw materials and the improvement of physicochemical properties. In order to promote the development of biofuels, the U.S. government has adopted strong subsidies.
1-1-2 Europe
Biodiesel is the most widely used in Europe, accounting for 5% of the finished oil. In 2001, the output of biodiesel has exceeded 1 million tons. It mainly uses rapeseed as raw material. At present, waste edible oils and fats, which were usually used as feed in European Union countries, are now turning to biodiesel production. According to the latest EU Biodiesel Market Report issued by Frost & Sulivan Enterprise Consulting Company, in order to achieve the Kyoto Protocol target of reducing carbon dioxide emissions by 8% in 2008-2012, the EU is about to introduce new regulations to encourage the development and use of biodiesel, such as the exemption of VAT on biodiesel and the stipulation that the use of biodiesel in motor vehicles accounts for the proportion of power fuels. Minimum share of gross material sales. In order to facilitate the promotion and use of biodiesel, Germany, Italy and other countries have also formulated technical standards, and formulated corresponding preferential policies, such as German farmers planting rapeseed as raw material for biodiesel can get 1,000 mark/ha subsidy, and the production of biodiesel will be exempted from tax.
By 2007, the turnover of biodiesel in EU will surge from 513.3 billion US dollars in 2000 to 2.4 billion US dollars, with an average annual growth rate of 25%. It is estimated that the total production of biodiesel in European countries will reach 8.3 million tons by 2010. In 2000, Germany’s biodiesel production reached 450,000 tons. In 2001, Germany invested 50 million marks in Haide to build 100,000 tons of biodiesel plant annually. There are seven biodiesel factories in France, with a total capacity of 400,000 t/a. The standard of use is to mix 5% biodiesel with ordinary diesel, and the tax rate on biodiesel is zero.
1-1-3 Other Countries
Japan began to produce biodiesel in 1995. At present, Japan produces 400,000 tons of waste edible oil annually, which provides abundant raw materials for biodiesel production. In the development plan for 2000-2005 formulated by the Japan Institute of Policy Science, 400,000 L of Biodiesel Blended with waste edible oil is required every year, that is, 1% of the diesel consumption in that year. There are four factories in Tokyo and Nagano, Japan, which use recirculating cooking oil to produce biodiesel at lower prices than petroleum-based diesel. The Japanese government has approved the sale of biodiesel as a commercial fuel by gas stations.
Thailand’s biodiesel development plan was launched in July 2001. The first biodiesel plant has been put into operation and tax relief policy has been implemented. Canadian Dynamotive Technologies announced that it had produced high-quality biodiesel by pyrolysis of bagasse in a 6-barrel/day (1 barrel = 158 L) bubbling fluidized bed unit. After 20 years of research, the Federal University of Ceara in northeastern Brazil transesterified castor oil with castor oil as raw material and sodium hydroxide as catalyst to produce biodiesel. PIB Engineering Company of Yugoslavia announced that its technology of producing biodiesel from rapeseed, developed in cooperation with several research institutes, has passed many tests by European environmental protection agencies and formally put into commercial production. In New Zealand, biodiesel is produced from by-product oils and fats of meat joint plants.
There are abundant vegetable oil and animal oil resources in our country. The output of soybean oil reaches 60 million tons every year, and the catering industry produces a large amount of frying oil. If we make full use of it, there will be great room for development. At present, the production and application of biodiesel have also been developed in China. Rapeseed oil, soybean oil, rice bran oil residue, industrial lard, butter and wild Tung seed oil have been successfully used as raw materials to produce biodiesel by esterification with methanol. Its products can not only be used directly as alternative fuels, but also as additives for clean diesel oil and some science and technology. The results have reached the international advanced level. For example, Hainan Zhenghe Bioenergy Company, Sichuan Gushan Oil Chemical Company and Fujian Excellent New Energy Development Company have developed technologies with independent intellectual property rights, and successively built factories with a scale of more than 10,000 tons. In addition, the enzymatic biodiesel production technology of Beijing University of Chemical Technology has achieved some results. The research involves the distribution, selection, breeding, genetic improvement and processing technology and equipment of oil plants.