留学生作业代写：Development and utilization of bioenergy

下面为大家整理一篇优秀的paper代写范文- Development and utilization of bioenergy，供大家参考学习，这篇论文讨论了生物能源的开发与利用。生物能源既是可再生能源，又是无污染或低污染的绿色能源。如今的生物能源主要是利用农作物、树木和其他植物及其残体，畜禽粪便，有机废弃物等可再生或循环的有机物质为原料。在世界资源日趋贫乏以及环境生态危机日显突出的情况下，生物能源的开发和普及将成为未来社会能源发展的趋势。

Bio-energy is a kind of green energy, which has been widely popularized in the world and has aroused the problems of food security, environmental pollution and energy efficiency. In order to develop and utilize rationally, we should make great efforts in developing the bio-energy which is suitable for the geographical conditions of our country from the national conditions and natural resources, at the same time speeding up the research on the efficiency of energy conversion and adopting the comprehensive development strategy of bioenergy.

Bioenergy mainly refers to the use of crops, trees and other plants and their residues, livestock manure, organic waste and other renewable or recycled organic materials for the production of energy.

Bioenergy mainly includes bio-energy and biofuels. Bio-electric energy is mainly used in various plant straw to generate electricity, while biofuels are produced by fermentation of methanol and ethanol fuel. Bioenergy is not only a renewable energy, but also a green source of pollution and pollution. The development and popularization of bioenergy will become the trend of the development of social energy in the future, when the world resources become scarce and the environmental ecological crisis becomes more and more obvious.

The rise in crude oil prices, countries have been widely concerned about the use of bio-energy to replace the chemical fuel, the U.S. plant structure and expansion of the speed of the rapid increase in alcohol production capacity, ethanol refineries in the United States began to build the site. The consumption of soybean oil in biodiesel is also increasing greatly, and the refining of the oil from the fiber will also step into the energy update plan.

The EU plan stipulates that certain biofuels must be included in transport fuels, and the European Commission has instructed to tighten biofuel production and subsidize biomass farming. Rapeseed oil is almost the raw material of biodiesel in all EU countries, which makes the rape acreage and rapeseed production in the EU grow rapidly. The EU also imports large amounts of palm oil from south-East Asia and biodiesel produced from palm oil.

Brazil's ethanol export growth has risen sharply as oil prices have soared. As one of the world's leading countries for bioethanol, sugar cane is the main ingredient for Brazilian ethanol refineries, and in southern Brazil, where crops and oilseed crops have been grown into sugarcane, the original production of soybeans in the Midwest will be planted in sugarcane.

The Argentine Government has provided greater growth opportunities for the biodiesel industry, and in encouraging biodiesel production, exports of biodiesel enjoy a lower tax rate than the export of raw materials such as corn and soybeans. To ensure high productivity in biodiesel production plants, Argentina is also planning to import products from other South American countries such as soybeans.

The rapid development of bioenergy can result in a large amount of land being used to grow some crops to produce bioenergy, which will result in inadequate supply of some of the agricultural products used for consumption, and higher prices, which burden the low-income earners. The massive use of corn and soybeans to produce biofuels in the United States, the world's largest exporter of corn and soybeans, could trigger a spike in food prices in international markets such as corn and soybeans, as well as rising prices for meat and livestock products, such as corn and soybeans. In the case of tighter food supply and demand, food will become one of the important national political bargaining weights and national strategic resources, and the issue of food security is becoming a core issue of international politics.

The emissions produced by biofuels in the process of production are the source of pollution and environmental pollution. In addition, the cultivation, refinement, transport and distribution of fuel crops can lead to other greenhouse gas emissions. Biofuels, if planted excessively, are detrimental to the growth of forests and other organisms and pose a certain threat to the ecological environment. "The development of bioenergy may trigger deforestation and bring more serious consequences to the environment than the use of fossil fuels, and may affect biodiversity," the U.N. Bulletin said in early 2009.

Energy gains in the life cycle of biofuel production are also one of the issues worth paying attention to. The production of energy crops, as well as the conversion of biofuel to biofuels and their distribution through transport, will require a significant amount of fossil energy, electrical energy and thermal energy throughout the life cycle. In the energy crisis and the food crisis increasingly intrusive human beings today, whether biofuels can truly achieve "energy economy" is worth discussing.

Even in the United States, where resources are well endowed, it is recognized that farmland and corn and soybeans are not sufficient to meet the demand for a substantial reduction in oil dependence. Energy crops generally can be divided into wood fiber and starch/sugar two series. There is no contradiction between the former and human consumption, so it is a hot spot of research and development and is expected to become the main raw material of "second generation biofuels" within 5-10 years. "Third generation biofuels" refers to oil-containing algae, which is more efficient for the conversion of solar energy. The oil content of microalgae in marine engineering is more than 40%, especially suitable for countries with richer sea areas or waters. Relying on biological technology and vigorously developing new energy plants is a key development direction of high quality bioenergy, such as genetic engineering modification of marine microalgae, which can shorten the growth period and increase the oil production. Some countries have begun to cultivate "energy grass" for drought-tolerant, hardy and salt-tolerant, fast growing and high yield. It is feasible to improve the starch content of cassava and sugar content of sweet sorghum stalk by breeding technology, and to reduce the lignin of sweet sorghum, switchgrass and other stem stalks by biotechnology.

The inputs of various energy crops, the single output, and the raw materials needed by the units are important indicators in the selection process of energy crops. "85", "95" during the plan period, the production of ethanol from sweet sorghum stalks was included in the Science and Technology Development Program by the National Science and Technology department, mainly because sweet sorghum was a strong competitor in the bio-energy system, with ethanol production of up to 3 per hectare. 92t, about 2.1 times as much as corn, and 1.3 times.

The feed of biodiesel includes oil plants with high fuel content. Screening of high quality biodiesel to obtain oil resources is an important way to solve the energy shortage, and the oil content and processing technology of all kinds of herbs and woody crops are important indexes of screening. During the "85" period, we studied systematically the distribution, selection, cultivation, genetic improvement, processing technology and equipment development of Jatropha Curcas, Yushu, and other oil plants, and at present, we have the technical basis of popularization and application.

The improvement of biomass conversion efficiency can improve the utilization rate of biomass and reduce environmental pollution, such as the technology of bio-conversion using fermented sugar in the process of fuel ethanol production, which is high speed, high efficiency and highly recovery. Study on the new solid catalyst in the process of biodiesel transformation The research and development of new production processes, such as supercritical and ultrasonic, and the conversion of discarded glycerol into high value-added products. Because cellulose can be extracted from weeds and even from waste paper, cellulose ethanol technology is widely regarded by experts as the real future of bioenergy industry. At present, China's cellulosic ethanol research and development technology has achieved phased results, and the international level is not large, but the distance between the realization of industrial production has a long time. In addition, it may be an important way to promote the industrialization of cellulosic ethanol by drawing on the experience of petrochemical industry, taking the model of bio-refining and ethanol-cogeneration, maximizing and expanding the economic value of the components of the substrate.

Energy crops are mainly related to shrubs and herbs, shrubs with willow and poplar, etc., including fine leaves, switchgrass and reeds, sweet sorghum, rapeseed, sugarcane, sweet potato and cassava. With the progress of science and technology, the category of energy crops has been expanding. Because of the difference of natural environment, development mode, development level, social environment, industrial form and national policy, the main energy crops in the world are different, and are also in constant adjustment. For example, Brazil used sugar cane to produce ethanol, the United States used corn to produce ethanol, but also to develop other energy crops such as switchgrass, Europe to rape and fast-growing dwarf forest, China's sweet sorghum to adapt to the north, sugarcane and cassava to adapt to the south planting.

From the perspective of sustainable development of energy crops, the environmental benefits of energy crops are established, and the cropping system and land system which are suitable to the environment are very important. In the area of energy crop cultivation, the potential ecological problems of long-term cultivation of the same energy crop should be prevented. In the absence of a complete solution to the food problem around the world, the problem of land competition for energy crops and food crops should be coordinated to reduce the negative impact of energy crops. The development of energy crops should take full advantage of barren slopes and saline-alkali land, focusing on non-food types of energy crops. Some energy crops can be on slopes, corner, saline and barren planting, not only to promote biodiversity, but also to a certain extent to improve the surrounding natural environment, such as sweet sorghum can be in the saline-alkali, tidal land, such as marginal soil growth good, its stem production of fuel ethanol will not compete with grain arable land, So it is a very good energy crop.

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