First of all, the cost of producing biodiesel from rapeseed oil is very high. According to statistics, 75% of the cost of biodiesel preparation is the cost of raw materials. Therefore, the key to the practical application of biodiesel is to adopt cheap raw materials and improve the conversion rate to reduce the cost.
Secondly, the chemical synthesis of biodiesel has the following disadvantages: complex process, excessive alcohol, high energy consumption and large equipment investment; Dark color, because unsaturated fatty acids in fat are easy to deteriorate at high temperature; The esterification product is difficult to recover and the recovery cost is high; Waste lye is discharged in the production process.
# # # Overview of biodiesel:
First, the main characteristics of biodiesel
Biodiesel is a clean and renewable energy source, which uses oil crops such as soybean, rapeseed, oil palm and Pistacia chinensis as oil.
Liquid fuel made of oil-bearing aquatic plants such as fruit, engineering microalgae, animal fat, waste oil from restaurants, etc.
Biodiesel is a typical "green energy" and a good substitute for petroleum diesel, so it should be developed vigorously.
Sustainable economic development, promoting energy substitution, reducing environmental pressure and controlling urban air pollution are of great strategic significance.
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As we all know, diesel molecules are composed of about 15 carbon chains. It is found that vegetable oil molecules are generally composed of 14- 18 carbon chains, which is similar to the carbon number of diesel molecules. Therefore, biodiesel is a new fuel made from renewable vegetable oil such as rapeseed. According to the chemical composition analysis, biodiesel is a kind of methane with high fatty acid, which is obtained from unsaturated oleic acid C 66.
1. has excellent environmental protection characteristics, mainly because of the low sulfur content in biodiesel, which makes the emission of sulfur dioxide and sulfide low, which can be reduced by about 30% (70% when there is catalyst); Biodiesel does not contain aromatic alkanes that will pollute the environment, so the waste gas is less harmful to human body than diesel. Tests show that compared with ordinary diesel, using biodiesel can reduce air toxicity by 90% and cancer incidence by 94%. Due to the high oxygen content of biodiesel, the smoke emitted during combustion is less, and the carbon monoxide emission is reduced by about 10% compared with diesel (95% when there is a catalyst); Biodiesel is highly biodegradable.
2. It has good low-temperature engine starting performance, and the cold filter point without additives reaches -20℃.
3. It has good lubrication performance, so that the wear rate of fuel injection pump, engine cylinder block and connecting rod is low and the service life is long.
4. It has good safety performance. Biodiesel is not dangerous because of its high flash point. Therefore, the safety in transportation, storage and use is obvious.
5. It has good fuel performance. The high cetane number makes it burn better than diesel oil, and the combustion residue is slightly acidic, which prolongs the service life of catalyst and engine oil.
6. It is renewable. As a renewable energy, unlike oil reserves, its supply will not be exhausted through the efforts of agricultural and biological scientists.
7. Diesel engines can be directly added for use without modification, and there is no need to add additional refueling equipment, storage equipment and specialized technical training of personnel.
8. Mixing biodiesel and petrochemical diesel in a certain proportion can reduce fuel consumption, improve power performance and reduce tail gas pollution.
The excellent performance of biodiesel makes the exhaust emission index of the engine using biodiesel not only meet the current Euro II standard, but even meet the stricter Euro III emission standard to be promulgated and implemented in Europe. Moreover, because the carbon dioxide emitted by biodiesel combustion is far lower than the carbon dioxide absorbed by plants when they grow, the global warming caused by carbon dioxide emission has been improved, which is a major environmental problem that harms human beings. Therefore, biodiesel is a real green diesel.
Second, the production method of biodiesel
At present, biodiesel is mainly produced by chemical method, that is, animal and vegetable oils react with low-carbon alcohols such as methanol or ethanol in acidic or alkaline catalyst and at high temperature (230-250℃) to generate corresponding fatty acid methyl ester or ethyl ester, and then biodiesel is obtained by washing and drying. Methanol or ethanol can be recovered in the production process, and the production equipment is the same as the general oil-making equipment, and about 65,438+00% by-product glycerol can be produced in the production process.
At present, the main problem of biodiesel is high cost. According to statistics, 75% of the cost of biodiesel preparation is the cost of raw materials. Therefore, the key to the practical application of biodiesel is to use cheap raw materials, improve the conversion rate and reduce the cost. The United States has begun to study plants with high oil content through genetic engineering, Japan uses industrial waste oil and waste frying oil, and Europe grows oil-rich crops on land unsuitable for growing food.
However, the chemical synthesis of biodiesel has the following disadvantages: the process is complex, the alcohol must be excessive, the subsequent process must have corresponding alcohol recovery device, the energy consumption is high, the color is dark, and the unsaturated fatty acids in fat are easy to deteriorate at high temperature; The esterification product is difficult to recover and the cost is high; Waste lye is discharged in the production process.
In order to solve the above problems, people began to study the synthesis of biodiesel by biological enzyme method, that is, animal fat and low-carbon alcohol were esterified by lipase to prepare the corresponding fatty acid methyl ester and ethyl ester. Enzymatic synthesis of biodiesel has the advantages of mild conditions, low alcohol consumption and no pollution discharge. But the main problem at present is that the conversion rate of methanol and ethanol is low, generally only 40%-60%. Because lipase is effective for esterification or transesterification of long-chain fatty alcohols, it is effective for short-chain fatty alcohols.
Glycerol and water are difficult to recover, which not only inhibits the formation of products, but also is toxic to immobilized enzyme, making the service life of immobilized enzyme short.
The production of diesel by "engineering microalgae" has opened up a new technical way for diesel production. The National Renewable Laboratory (NREL) of the United States has constructed "engineering microalgae" through modern biotechnology, that is, "engineering microalgae" of diatoms. Under laboratory conditions, the lipid content of "engineered microalgae" can be increased to more than 60%, and outdoor production can also be increased to more than 40%. Generally speaking, the lipid content of microalgae is
It has played an important role. At present, we are studying the selection of appropriate molecular vectors to fully express ACC gene in bacteria, yeast and plants, and further introduce the modified ACC gene into microalgae to obtain more efficient expression. Using "engineering microalgae" to produce diesel oil has important economic and ecological significance. Its advantages are high microalgae production capacity, and the use of seawater as a natural culture medium saves agricultural resources. It is dozens of times higher than terrestrial plants. The produced biodiesel does not contain sulfur, emits no toxic gas when burning, can be degraded by microorganisms when discharged into the environment, does not pollute the environment, and is rich in oil.
High-quality microalgae or "engineering microalgae" is a great advantage in producing biodiesel.
Third, the morning of developing biodiesel abroad.
Biodiesel was born in 1988. It was invented by Nilgon Company in Germany. It is a clean fuel extracted from rapeseed oil. Its outstanding environmental protection and renewability have attracted great attention from developed countries, especially resource-poor countries. Encouraged by industry norms and policies, western countries have taken a series of positive measures to develop biodiesel. In order to facilitate the popularization and use, Germany, Italy and other countries have formulated technical standards for biodiesel. For example, American authority ASTM issued standards in 1996 and 2000 to improve the industrialization conditions of biodiesel, which was actively encouraged by the government.
For example, German farmers can get a subsidy of 1000 DM/hectare for planting rapeseed with biodiesel as raw material, and the production of biodiesel is tax-free.
In Europe and North America, biodiesel production from residual rapeseed oil and soybean oil has been widely used. At present, biodiesel is mainly produced by chemical method. Vegetable oil is esterified with methanol or ethanol in acidic or alkaline catalyst at 230-250℃ to generate corresponding fatty acid methyl ester or ethyl ester biodiesel. The technology of synthesizing biodiesel by biological enzyme method is still under study. Compared with ordinary diesel, biodiesel is more conducive to environmental protection. The emission of toxic organic matter in diesel vehicle exhaust is only110, particulate matter is 20%, and the emission of CO2 and CO is only 10%. According to the Kyoto Protocol, the European Union will request that the deadline be 2008-20 12.
Reduce emissions by 8%. According to the life cycle analysis of the influence of fuel on CO2 in the whole atmosphere, the CO2 emitted by biodiesel is about 50% less than that of fossil diesel. Therefore, the EU recently issued two new directives to promote the application of biodiesel in the automobile fuel market, which will further promote the development of biodiesel industry in Europe. Compared with traditional diesel, the price of biodiesel is more than twice as high. Therefore, the new directive requires EU countries to reduce the tax rate of biodiesel and determine the sales proportion of biodiesel in European automobile fuel.
The biodiesel industry in western countries has developed rapidly. In recent years, western countries have increased their investment in the commercialization of biodiesel, which has increased the investment scale and the number of projects started. The United States, Canada, Brazil, Japan, Australia, India and other countries are actively developing this industry. At present, there are four biodiesel production plants in the United States with a total production capacity of 300,000 tons/year. EU countries mainly use rapeseed as raw material. In 200 1 year, the output of biodiesel has exceeded 1 10,000 tons. In 2000, the biodiesel in Germany reached 450,000 tons. Germany also invested 50 million marks in Hyde area on June 1 1 day, 2006, with an annual output of 10.
Ten thousand tons of biodiesel plant. France has seven biodiesel production plants with a total capacity of 400,000 tons/year. The use standard is to add 5% biodiesel to ordinary diesel, and the tax rate of biodiesel is zero. There are 9 biodiesel production plants in Italy with a total production capacity of 330,000 tons/year, and the biodiesel tax rate is zero. Austria has three biodiesel production plants with a total production capacity of 55,000 tons/year, and the tax rate is 4.6 of that of petroleum diesel.
Fourthly, the development of biodiesel in China.
Our government has formulated some policies and measures to solve the problems of energy saving, substitution and environmental protection. Some scholars and experts have devoted themselves to the research of biodiesel, and this research will make a breakthrough and reach the practical level.
Academician Min Enze, a famous scholar, clearly put forward the topic of developing clean-fuel biodiesel for the first time in the book Green Chemistry and Chemical Engineering: the former Ministry of Machinery Industry and the former sinopec group allocated special funds in the 1980s, and the project was undertaken by Shanghai Internal Combustion Engine Research Institute and Yishan Agricultural Machinery in Guiwai for 10 year, and invited Zhan, an expert from China Petrochemical Research Institute, to do a lot of basic experiments and explorations; Mr. Shi Delu from China Agricultural Engineering Research and Design Institute also conducted experiments on biodiesel in 1985. The Sino-European cooperative research project undertaken by Liaoning Energy Research Institute also involves biodiesel; China University of Science and Technology, Henan Polytechnic University and Army Institute of Chemistry have also conducted research on biodiesel to varying degrees.
The systematic research began with the key scientific research project of the Eighth Five-Year Plan of Chinese Academy of Sciences: "Research and Application Technology of Oil Plants", and completed the investigation of oil plant resources and the research of cultivation techniques in Jinsha River basin, and established a 30-hectare demonstration film of Jatropha curcas cultivation. Since the early 1990s, Changsha Institute of New Technology and Hunan Academy of Forestry have carried out the cooperative research on energy plants and biodiesel for 10 years, and completed the smooth skin during the Eighth Five-Year Plan period. During the Ninth Five-Year Plan period, the national key scientific research project "Plants" was completed.
Petroleum energy utilization technology ".
During the period of 1999-2002, Hunan Academy of Forestry undertook and presided over the introduction of foreign advanced forestry technology (948 Project) by the State Forestry Administration, that is, "the introduction of energy tree species Lvwangshu and its utilization technology", and introduced excellent clones of energy tree species eucalyptus Tim-calli from South Africa, the United States and Brazil. Developed the milk extraction equipment of green Yushu; The composition and fuel characteristics of elm latex were studied.
However, compared with foreign countries, there is still a considerable gap in the development of biodiesel in China, which lingers in the primary research stage for a long time and fails to form the industrialization of biodiesel. The government has not yet issued a set of policies and measures to support, preferential and encourage biodiesel, nor has it formulated a unified standard for biodiesel and implemented an industrialization development strategy. Therefore, after China's entry into WTO, under the background of rapid economic development, environmental protection and dual pressures, it is more urgent to accelerate the industrialization of efficient and clean biodiesel.
Verb (abbreviation of verb) The prospect of biodiesel industrialization in China
In 2003, driven by the sustained and rapid growth of the national economy, China's oil market demand grew strongly, and the total demand for refined oil increased by double digits, reaching 1 1.4%, an increase of 7.4 percentage points over the previous year, which promoted the substantial growth of oil imports and made China a big oil consumer and importer. According to the statistics of China Logistics Information Center, the cumulative average price of petroleum and its products in China in 2003 increased by 1 1.8% compared with the previous year. According to preliminary analysis, the supply and demand situation of China oil market in 2004 is basically similar to that in 2003, and consumption will continue to be maintained.
Demand is strong and supply and demand are basically balanced, but local and structural supply shortages caused by seasonality and transportation factors are not ruled out. It is estimated that the consumption of crude oil in China in 2004 will be 270 million tons, and the net import may exceed 654.38 billion tons.
China is a net importer of oil, and its oil reserves are very limited. A large amount of imported oil poses a threat to China's energy security. Therefore, improving the quality of oil products is more practical for China. Biodiesel has three advantages: renewable, clean and safe. Experts believe that biodiesel is of great strategic significance to the adjustment of agricultural structure, energy security and comprehensive management of ecological environment in China. At present, automobile diesel has become a development direction of automobile industry. According to experts' prediction, by 20 10, the world demand for diesel will increase from 38% to 45%, and the supply of diesel is seriously insufficient, which provides a broad development space for rapeseed to produce biodiesel. The development of biodiesel industry can also promote the rural, economic and social development of China. For example, developing oil crops to produce biodiesel can open a way to transform agricultural and forestry products into industrial products, which is conducive to adjusting agricultural structure and increasing farmers' income.
The balance between supply and demand of diesel oil will also be the focus of the development of China oil market for a long time to come. Insiders pointed out that by 2005, with the increase of China's original processing capacity, there will be some export space for gasoline and kerosene, but the diesel supply gap is still large. It is predicted that by 2065.438+00, the demand for diesel will exceed 654.38 billion tons, an increase of 24% over 2005. By 20 15 years, the market demand will reach about1300,000 tons. In recent years, although refining and chemical enterprises have continuously improved the production ratio of diesel and steam through continuous technological transformation, they still cannot meet the requirements of diesel and steam consumption ratio. At present, production
The ratio of diesel to gasoline is about 1.8, but the consumption ratio of diesel to gasoline in the market is above 2.0, and the consumption ratio of diesel to gasoline in Yunnan, Guangxi, Guizhou and other provinces is even above 2.5. With the acceleration of the development of the western region and the start of major infrastructure projects in the national economy, the contradiction between diesel and gasoline is more prominent. Therefore, the development of biodiesel is not only in line with the direction of adjusting oil product structure and improving diesel-gasoline ratio in petrochemical industry at present.
At present, China's biodiesel technology has made great achievements: Hainan Zhenghe Bioenergy Company, Sichuan Gushan Grease Chemical Company and Fujian Zhuoyue New Energy Development Company have all developed technologies with independent intellectual property rights, and successively built production facilities with a scale of over 10,000 tons, which indicates that biodiesel, a high-tech industry, has been born in China.
The person in charge of China Academy of Engineering said that the development of various petroleum substitutes was put forward in China's "Tenth Five-Year Plan", and the development of bio-liquid fuel was determined as the national industrial development direction. Biodiesel industry has been supported by the leaders of the State Council, the State Planning Commission, the State Economic and Trade Commission, the Ministry of Science and Technology and other government departments, and has been included in the relevant national plans.
China is rich in raw material resources for the development of biodiesel. China has a vast territory, a large geographical span, different distribution of water and heat resources, and rich and diverse energy plant resources. The main families are Euphorbiaceae, Lauraceae, Myrtaceae, Apocynaceae, Compositae, Leguminosae, Cornaceae, hyacinthus orientalis and Araliaceae. At present, the development and utilization of biodiesel in China is still in the early stage of development. It is necessary to reduce the cost of biodiesel as a whole and make it
With the deepening of reform and opening-up, in the process of global economic integration, under the favorable situation of China's accession to the WTO, China's economic level will be further improved, and its demand for energy will increase. As long as the research results of biodiesel are transformed into productivity and industrialized, its application in diesel engines, diesel power plants, air conditioning equipment, rural fuels and so on will be very broad.
# # # New technology:
After years of painstaking research, this proprietary technology has finally developed a high-tech new energy product-caocao hydrocarbon. This product is made of various plant straws and grasses as raw materials, mixed with some heavy hydrocarbon raw materials by grinding and fermentation, and sublimated by the group enzyme elements of biological dihydrogen conversion factors in the middle. Caocao hydrocarbon can extract light diesel oil from heavy hydrocarbon raw materials, and its calorific value can reach 6.5438+0.2 million kcal, which has passed the national first-class intelligence unit.