English name: energy plant English name: energy plant Definition: Herbs and woody plants with high sugar content (hydrocarbons) planted specially for providing energy raw materials. Applied discipline: electric power (first-class discipline); Renewable Energy (two disciplines) This content was approved and published by the National Committee for the Examination and Approval of Scientific and Technological Terminology.

Energy plants-Eucalyptus can be used as energy plants. With the continuous depletion of fossil energy, people began to look for alternative energy sources around the world.

Energy factory

There are many kinds of plants that can be used as energy, mainly some crops and organic residues, forest and forestry industrial residues, algae and aquatic plants are also energy plants to be developed. Using plants as energy can be used as solid fuel, and can also be converted into carbon, combustible gas or bio-crude oil by scientific methods. In forestry energy, foreign countries attach importance to cultivating trees with fast growth, high photosynthetic efficiency and strong reproduction. There are more than 60 kinds of energy plants in China Academy of Forestry. There are two ways to use forest energy: dry distillation to extract gas, tar and carbon; Direct combustion of petroleum plants is also a new field opened up in recent years. Oil is a non-renewable energy source, so its exhaustion is inevitable and inevitable. Therefore, many countries are carrying out research on alternative energy, and the research on energy plants comes into being. Professor Carl, the American Nobel Prize winner, developed the first artificial oil plant as early as 1984, and obtained the harvest of crude oil per hectare 120- 140 barrels. At present, the United States has planted millions of acres of petroleum plants, Britain has also developed 6.5438+0.5 million acres, and Switzerland has also formulated a plan to replace half of the country's oil consumption with vegetable oil. Europe and North America also grow a large number of perennial herbs as fuel to generate electricity, such as elephant grass. Britain also found that grassland nettle, large nettle, high sand grass and other plants grow rapidly and are important energy plants. There are Euphorbiaceae Euphorbia, red coral and sea paint, which are also ideal fuel plants. Pittosporum, also known as petroleum fruit, is a potential petroleum substitute. Brazil's shampoo tree, dig a hole in the tree and the oil will flow out.  grass in the United States, giant algae on the west coast and tufted algae in Australia can also extract oil. There are also many petroleum plants in China, such as Shannan Tree and Eucalyptus, which can produce high oil. According to the identification of scientists, there are more than 65,438+00 species of herbs, 65,438+08 species of shrubs, 23 species of trees and 65,438+08 species of shrubs in the Asia-Pacific region as productive energy plants.

Energy plants rich in similar petroleum components

Broussonetia papyrifera, green elm, Xigu coconut, Jatropha curcas and Hevea brasiliensis all belong to this kind of plants. For example, the milk secreted by Hevea brasiliensis is very similar to petroleum, and can be directly used as diesel oil without refining, with an annual output of 40L per tree. South tree oil is a special vegetable oil in Hainan Province, China. Its trunk contains a light brown flammable oily liquid similar to kerosene. Drill a hole in the trunk, and this liquid will flow out, and it can also be directly used as fuel oil.

Rich in carbohydrates such as high sugar, high starch and cellulose.

The final product obtained by using these plants is ethanol. These plants are various and widely distributed, such as cassava, potato, Jerusalem artichoke, beet, sugarcane, sorghum and corn, which are all good raw materials for ethanol production.

Oil-rich energy plants

This plant is not only an important part of human food, but also a very widely used raw material in industry. Processing oil-rich energy plants is an effective way to prepare biodiesel. There are more than 10,000 kinds of oil-rich plants in the world, and there are nearly 1,000 kinds in China, some of which have high oil content. For example, the oil content of Litsea cubeba seeds in northern Guangxi is 64.4%, and that of Cinnamomum camphora seeds in Lauraceae is 67.2%. Some species of this plant have great storage capacity. For example, Xanthium sibiricum with oil content 15% ~ 25% is widely distributed in North China, Northeast China and Northwest China, and is rich in resources. The annual output of Shaanxi province alone reaches 13500 t ... Artemisia sphaerocephala and Artemisia sphaerocephala are mainly distributed in Inner Mongolia, Shaanxi, Gansu and Ningxia, with an oil content of 16% ~ 23% and a reserve of 500,000t ... Some higher freshwater plants such as peanut, water hyacinth and water hyacinth also have great oil production potential.

Fuel wood energy plants

This plant mainly provides firewood and charcoal. Such as Salicaceae, Myrtaceae, Eucalyptus, Leucaena, etc. At present, the better firewood trees in the world are Canadian poplar, Italian poplar and American phoenix tree. In recent years, China has developed some tree species suitable for fuelwood, such as Amorpha fruticosa, Elaeagnus angustifolia, Salix matsudana and Paulownia. In some places, it takes 3-5 years to grow firewood forests, and the average firewood forest can produce about 15t. The awn grass planted in the United States is highly flammable, and the harvested hay can be easily made into fuel for power generation in power plants by using the existing technology.

Development prospect of renewable energy

With more and more countries adopting policies and measures to encourage renewable energy, the production scale and application scope of renewable energy are expanding. In 2007, the global renewable energy generation capacity reached 240,000 MW, an increase of 50% over 2004. In 2007, at least 60 countries formulated relevant policies to promote sustainable energy development. The European Union has set the goal that sustainable energy accounts for 20% of the total energy by 2020, and China has also set the goal that renewable energy accounts for 0/5% of the total energy by 2020. Since the implementation of the Renewable Energy Law on June 5438+ 10, 2006, China's renewable energy has entered a period of rapid development. In 2007, the total investment of renewable energy projects in China reached 654.38+0.2 billion US dollars, ranking second in the world. Among the 4 trillion investment plans announced from June 65438 to October 2008 10, there is no doubt that there is an investment plan to develop new clean energy. Natural gas, nuclear energy and hydropower have become priority development targets. According to China's medium and long-term energy plan, by 2020, China can basically rely on conventional energy to meet the energy demand of national economic development and people's living standards. By 2020, the total utilization of renewable energy in China is equivalent to 600 million tons of standard coal, which will play a greater role in China's energy structure adjustment, reducing greenhouse gas emissions and protecting the ecological environment.

manufacturing technique

Biodiesel production

Chemical sorghum

Biodiesel is mainly produced by chemical method in the world, that is, at a certain temperature, animal and vegetable oils and low-carbon alcohols undergo ester exchange reaction under the catalysis of acid or alkali to generate corresponding fatty acid esters, and then biodiesel is obtained after 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 the by-product in the production process is about 10% glycerol. However, the chemical production process is complex, and alcohol is definitely excessive; The moisture and free fatty acids in oil raw materials will seriously affect the yield and quality of biodiesel; The product purification is complex, the esterification product is difficult to recover and the cost is high; The subsequent process must have a corresponding recovery device, which has high energy consumption and low recovery rate of by-product glycerol. The use of acid-base catalysis causes serious corrosion to equipment and pipelines, and a large amount of wastewater is produced by using acid-base catalysis, and the discharge of waste alkali (acid) solution is easy to cause secondary pollution to the environment. In view of the problems existing in the production of biodiesel by chemical method, people began to study the synthesis of biodiesel by biological enzyme method, that is, the corresponding fatty acid methyl ester and ethyl ester were prepared by transesterification with lipase. Enzymatic synthesis of biodiesel requires less equipment, mild reaction conditions, less alcohol consumption and no pollution discharge. Using soybean oil as raw material, the immobilized enzyme process was adopted. The amount of enzyme is 30% of the oil, the molar ratio of methanol to soybean oil is 12: 1, the reaction temperature is 40℃, and the yield of biodiesel is 92%. Biodiesel prepared by biological enzyme method has not been popularized in industrialization because of its high cost and short storage time. In addition, there are still some problems that restrict the industrial production of biodiesel by biological enzyme method. For example, lipase can effectively esterify or transesterify long-chain fatty alcohols, but the conversion rate of short-chain fatty alcohols is low (for example, methanol or ethanol is generally only 40%-60%); Short-chain fatty alcohols are toxic to enzymes, which are easily inactivated. By-product glycerol is difficult to recover, which not only inhibits the formation of products, but also is toxic to enzymes. Supercritical extraction of Machilus yunnanensis

That is, when the temperature exceeds its critical temperature, gas and liquid will be indistinguishable, so the substance is in a flowing state and will not condense when any pressure is applied. The density of supercritical fluid is close to liquid, the viscosity is close to gas, and the thermal conductivity and diffusion coefficient are between gas and liquid, so extraction and reaction can be carried out at the same time. Supercritical method can obtain rapid chemical reaction and high conversion rate. Kusdiana and Saka found that rapeseed oil can be converted into biodiesel by supercritical methanol within 4 minutes, and the conversion rate is over 95%. However, it needs high temperature and high pressure, and the requirements for equipment are very strict, and a lot of research work is needed before mass production.

Bioethanol production

The production of bioethanol is a process in which macromolecules such as cellulose and starch, which are widely found in nature, are used as raw materials and converted into ethanol by physical and chemical means and biological means. The production process includes three main parts: raw material collection and treatment, glycolysis, ethanol fermentation and ethanol recovery. There are many sources of raw materials for producing fuel alcohol by fermentation, which are mainly divided into sugar raw materials, starch raw materials and cellulose raw materials, among which the technology of fermenting alcohol with sugar raw materials is the most mature and the cost is the lowest. Wood fiber raw materials need pretreatment before enzymolysis and fermentation, among which ammonia explosion fiber technology is considered as the most promising pretreatment method. With the breeding of yeast with high temperature tolerance, high sugar tolerance and high alcohol tolerance, and the improvement of underflow feeding technology and fermentation separation coupling technology, the cost of alcohol industrial fermentation will be lower and lower.

Development and utilization

international

Ximondm

The international research on energy plants began in the late 1950s and early 1960s, developed in the 1970s and developed rapidly since 1980s. During the period of 1986, Dr. Calvin, the Nobel Prize winner of the University of California, successfully introduced Euphorbia lathyris, Ulmus pumila and other tree species with high development value in California, and harvested 120- 140 barrels of oil per hectare. He also carried out feasibility analysis and research on industrial application, and proposed to create an "oil plantation", which pioneered the artificial planting of oil plants. So far, there has been a rapid upsurge in the development and research of energy plants around the world, and many countries have formulated corresponding development and research plans. For example, Japan's "Sunshine Plan", India's "Green Energy Project", America's "Energy Farm" and Brazil's "Alcohol Energy Plan". With the discovery of more plants such as "diesel tree", "alcohol tree" and "wax tree" and the continuous maturity of cultivation techniques, "petroleum botanical gardens" and "energy forest farms" have been established all over the world to plant some plants that produce similar petroleum fuels. Britain, France, Japan, Brazil, Russia and other countries have also carried out research and application of petroleum plants, cultivated new tree species with the help of genetic engineering technology, and adopted more advanced cultivation techniques to increase production. At present (20 10), the United States has planted more than one million hectares of fast-growing oil forests, and established research bases for oil plants such as Populus deltoides, Alnus cremastogyne, Sophora japonica and eucalyptus. There are 6.5438+0.2 million hectares of acacia trees in the Philippines, and 6.5438+0.0 million barrels of oil can be collected after 6 years. In Japan, a 50,000-square-meter experimental field of oil plants was established, and 6,543.8+0.5 million oil plants were planted, with an annual output of more than 654.38+0.000 barrels of oil. Switzerland's "Green Energy Plan" plans to plant 654.38 million hectares of oil crops in 10 year to meet 50% of the country's annual oil demand. Thailand's automobile fuel gas station made of coconut oil opened in Bashu, central Thailand, becoming the first coconut oil gas station in the world. Brazil is the most distinctive country in the development and application of ethanol fuel, and has implemented the largest "ethanol planting" plan in the world. In 2004, Brazil's ethanol production reached 654.38+0.46 billion, and its ethanol consumption exceeded 654.38+0.22 billion. Brazil's ethanol production accounts for 44% of the world's total output and 66% of its export volume. The United States has adopted genetic engineering technology. Lignocellulose was successfully converted into ethanol. 20 10 in March, Viacheslav Andrianov, a researcher in the laboratory of the Biotechnology Foundation of Thomas Jefferson University in the United States, said that compared with other plants, tobacco leaves can extract more oil and sugar and are attractive "energy plants". Andrianov's research team changed the gene of tobacco, which greatly increased the oil content of tobacco leaves. The tobacco oil extracted from reconstituted tobacco leaves is 2 1 times that of ordinary tobacco leaves. The researchers said that the oil content of tobacco after transgenic is greatly improved, which is expected to "transform" into biofuel, providing new ideas for solving the current energy crisis.

China

Rubber tree in Brazil

China is a "big oil-poor country" and a big energy consumer in the world. 1993, China changed from a net oil exporter to a net oil importer, and its oil imports increased year by year. At present, its dependence on oil imports has exceeded 1/3. The research, development and utilization of energy plants in China started late, and there is still a big gap compared with developed countries in Europe and America. However, China is rich in plant resources. Plant samples were analyzed as early as 158 1 year 1982. A total of 974 plants were collected and sorted into China Oily Plants and Sichuan Oily Plants, and some plants with high oil content were screened out, such as Sapium sebiferum, Phoebe bournei, Tetraena mongolica and Wujiaojiao. It has been found that there are 697 genera 15 1 family 1554 species of oil plants in China, and there are 154 species of plants with oil content above 40%. Although the utilization of energy plants in China is in the primary stage, the biodiesel industry has been highly valued and supported by the leaders of the State Council and 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 national plan. During the Seventh Five-Year Plan period, Sichuan Academy of Forestry and other units successfully extracted biodiesel from wild Jatropha curcas (the fruit of Jatropha curcas). The research and application technology of fuel oil plants, a key project of the Eighth Five-Year Plan of China Academy of Sciences, completed the investigation and study of fuel oil plant resources in Jinsha River basin, and established a demonstration area for jatropha curcas cultivation. During this period, Hunan province completed the research on the technology of making methyl ester fuel oil from bark trees and its combustion characteristics; During the Ninth Five-Year Plan period, according to the framework of the Outline for the Development of New and Renewable Energy, in the plans formulated by the relevant ministries and commissions of the central government and local governments, the key points are as follows: conducting a nationwide survey of green energy plant resources to provide scientific basis for making long-term research and development; Using genetic engineering and hybrid breeding technology to cultivate new varieties with high yield and short renewal period; Carry out basic research and development research on energy plant fuel, including combustion characteristics, refining technology, comprehensive utilization and development of energy plants. The research and development of energy plant products in China mainly focuses on biodiesel and ethanol fuel. The research content of biodiesel involves the distribution, selection, cultivation, genetic improvement, processing technology and equipment of oil plants. The main raw materials for biodiesel production are rapeseed, soybean, jatropha curcas, Pistacia chinensis, Yunnan Runnan and so on. Jatropha curcas oil content is as high as 40%-60%, which is an ideal raw material for biodiesel.