China energy development direction

Development Direction and Countermeasures of Biomass Energy in China

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Biological bridge

Biomass energy is solar energy fixed on the earth through plant photosynthesis, and it is most likely to become one of the main new energy sources in 2 1 century. It is estimated that the energy stored by plants every year is about 10 times of the world's main fuel consumption; And the utilization as energy is less than 1% of its total amount. In order to complete the carbon cycle in nature, most of these unused biomass will release energy and carbon through natural decomposition and return to nature. In fact, biomass energy is the earliest, most and most direct energy used by human beings. Up to now, more than 654.38+0.5 billion people in the world still use biomass as their living energy. Biomass combustion is a traditional way of utilization, which not only has low thermal efficiency, but also has high labor intensity and serious pollution. Through biomass energy conversion technology, biomass energy can be efficiently used to produce various clean fuels, replacing coal, oil, natural gas and other fuels to generate electricity. And reduce dependence on mineral energy, protect national energy resources, and reduce environmental pollution caused by energy consumption. Experts believe that biomass energy will become an important part of sustainable energy in the future. By 20 15, 40% of global energy consumption will come from biomass energy.

1.2 energy and environment

Mankind is facing the dual pressures of development and environment. Energy is an important driving force for economic and social development. The more the economy develops, the more energy consumption, especially the increase of fossil fuel consumption. There are two outstanding problems before us: one is the increasingly serious environmental pollution, and the other is that the existing fossil fuels on the earth will be dug up one day. According to consumption, the world oil resources will be exhausted in the next 50 to 80 years. By 2059, the 200th anniversary of the first oil well drilling in the world, there may be little oil resources left in the world. On the other hand, the excessive consumption of fossil fuels consumes these limited resources too quickly and prematurely, releasing a lot of redundant energy and carbon, breaking the balance between energy and carbon in nature, which is the direct factor causing catastrophic consequences such as ozone layer destruction, global warming and acid rain. That is to say, if new energy sources are not developed to replace the dominant position of fossil conventional energy sources in the energy structure, a serious and disastrous energy and environmental crisis will occur in 2 1 century, which is one of the three most likely disasters that mankind will face in the next century.

1.3 national security

Of course, developing biomass energy is not the only way to obtain new energy. Humans can acquire nuclear energy through high-tech means, even from outer space, but the harm is obvious to all. First of all, the development of nuclear energy is likely to bring new unstable factors to the already uneasy world, and even directly threaten the living environment of mankind; Secondly, the energy development carried out by a country or group in the limited outer space area that human beings can reach at the technological level in the next century will inevitably lead to new struggles or disputes, and its fortunes are self-evident. Biomass energy is not only the safest and most stable energy, but also different kinds of energy can be produced through a series of conversion technologies, such as curing and carbonization to produce organic fuel, gasification to produce gas fuel, liquefaction and vegetable oil to obtain liquid fuel, and electricity can be produced if necessary. At present, all countries in the world, especially developed countries, are committed to developing efficient and pollution-free biomass energy utilization technology, protecting their own mineral energy resources and providing fundamental guarantee for the sustainable development of the national economy.

2. Development of biomass energy technology abroad

The development and utilization of biomass energy has long been concerned by governments and scientists all over the world. Many countries have made corresponding development and research plans, such as Japan's sunshine plan, India's green energy project, American energy farms and Brazil's alcohol energy plan. Other countries, such as Denmark, Netherlands, Germany, France, Canada and Finland, have been conducting their own research and development for many years, and have formed their own unique biomass energy research and development system with their own technological advantages.

2. 1 biogas technology

Anaerobic method is mainly used to treat livestock manure and high concentration organic wastewater, which is the early development of biomass energy utilization technology. Before 1980s, developing countries mainly developed biogas digester technology, using crop straws and livestock manure as raw materials to produce biogas as cooking fuel. Such as domestic biogas digesters in India and China; However, developed countries mainly develop anaerobic technology to treat livestock manure and high-concentration organic wastewater. At present, developed countries such as Japan, Denmark, the Netherlands, Germany, France and the United States generally adopt anaerobic treatment of livestock manure, and developing countries such as India, the Philippines and Thailand have also built large and medium-sized biogas projects to treat livestock manure. Adopt a new self-circulating anaerobic technology. Dutch IC Company made the gas production rate of anaerobic treatment of beer wastewater reach the level of 65438+1100m3/m3.d, which greatly saved investment, operating expenses and occupied area. The United States, Britain, Italy and other developed countries mainly use biogas technology to treat garbage. Staten Waste Treatment Station in new york, USA invested 20 million US dollars to treat waste by wet method, and produced 260,000 m3 of biogas per day for power generation and fertilizer recovery. The benefit is considerable, and it is estimated that the total investment can be recovered in 10. Britain has already achieved 18MW garbage biogas power generation, and will invest 10.50 billion pounds to build more garbage biogas power plants in the next10 year.

2.2 Biomass pyrolysis and gasification

As early as 1970s, some developed countries, such as the United States, Japan, Canada and European countries, began to research and develop biomass pyrolysis gasification technology. By the 1980s, there were 19 companies and research institutions in the United States engaged in the research and development of biomass pyrolysis and gasification technology. The laboratory of Canada 12 University is conducting research on biomass pyrolysis and gasification technology; In addition, the Philippines, Malaysia, India, Indonesia and other developing countries have also carried out research in this field. Tampere Power Company of Finland began to build a waste wood gasification power plant in Sweden, with an installed capacity of 60MW and a heat output of 65mW. 196, the Swedish Energy Center obtained a loan from the World Bank, and planned to build a power plant with an installed capacity of 20-3mw in Brazil, using advanced technologies such as biomass gasification and combined cycle power generation to treat the rich local bagasse resources.

2.3 Biomass liquid fuel

Another interesting technology, because biomass liquid fuels, including ethanol and vegetable oil, can directly replace petroleum fuels such as gasoline as clean fuels. Brazil is the most distinctive country in the development and application of ethanol fuel. In the mid-1970s, in order to get rid of excessive dependence on imported oil, the world's largest ethanol development plan was implemented. By 199 1, the ethanol output reached1300 million liters. Of the 9.8 million vehicles, nearly 4 million are pure ethanol vehicles, and most of the rest use 20% ethanol fuel. 1996, the renewable resources laboratory of the United States developed the technology of producing alcohol from cellulose waste, and haskell industrial group of the United States established the 1MW rice husk power generation demonstration project: the annual processing capacity of rice husk10.2 million tons, the annual power generation capacity of 8 million kwh, and the annual output of alcohol of 2,500 tons, with obvious economic benefits.

2.4 Other technologies

In addition, biomass compression technology can be used to compress solid agricultural and forestry wastes into briquette fuel that can replace coal. For example, the United States has developed biomass pellet molding fuel; Thailand, Philippines, Malaysia and other third world countries have developed rod-shaped fuel.

3. Biomass energy in China

China is basically an agricultural country, and the rural population accounts for more than 70% of the total population. Biomass has always been one of the main energy sources in rural areas, and it also occupies a favorable position in the national energy composition.

3. 1 biomass energy

The existing area of forest, grassland and cultivated land in China is 410.40 billion hectares, and the theoretical biomass resources can reach more than 65 billion tons/year (the amount of organic carbon produced by plants through photosynthesis in the first square kilometer of land area is about10.58 tons/year). If the average calorific value is 15000 kJ/kg, the theoretical resource is at most 3.3 billion standard coal, which is equivalent to more than three times the total annual energy consumption in China.

In fact, at present, the biomass that can be used as energy mainly includes straw, firewood, livestock manure, domestic garbage, organic waste residue and wastewater. According to the survey, at present, the straw resources in China have exceeded 720 million tons, about 360 million tons of standard coal. Except about 654.38+0.2 billion tons used for feed, paper making, textile and building materials, the remaining 600 million tons can be used as energy: the main sources of fuelwood are forestry harvesting, afforestation pruning and firewood forest. According to a survey, the average annual output of fuelwood in China is about 65.438+0.27 billion tons, which is equivalent to 74 million tons of standard coal. The output of municipal solid waste is about 654.38+0.2 billion tons, increasing by 8%-654.38+0% every year. It is estimated that the total exploitable biomass energy resources in China are about 700 million tons of standard coal.

3.2 Biomass Energy and Its Utilization

The energy utilization of biomass in China is mostly used for rural living energy, and rarely used for industrial production of township enterprises. However, direct combustion has been the main utilization mode for a long time, and in recent years, new technologies have been adopted to utilize biomass energy, but the scale is small. The popularization degree is low, and it accounts for a very small proportion in the energy structure of the whole country and even rural areas.

Direct combustion of biomass not only has low thermal efficiency, but also makes people's living environment worse and worse due to the discharge of a large amount of smoke and dust, which seriously damages the physical and mental health of women and children. In addition, it also has extremely adverse effects on ecology, society and economy:

1. In the case of unreasonable utilization of biomass energy, unreasonable felling of natural resources such as forests will destroy natural vegetation and ecological balance;

2. Organic garbage, organic wastewater, organic waste residue, livestock manure and some agricultural wastes are not fully utilized, which not only wastes resources, but also makes them the main source of organic pollution, which not only causes serious air and water pollution, but also emits a lot of greenhouse gases, which intensifies the global greenhouse effect;

3. At the same time, with the rapid development of economy and the improvement of people's living standards, the problem of energy shortage is bound to become a major problem hindering the sustainable development of the national economy in the 2/kloc-0 century, which must be paid enough attention to and solved by effective measures.

In fact, vigorously developing and utilizing biomass energy is of great significance to alleviate the energy, environment and ecological problems in the 2 1 century, and has produced many benefits.

4. Reduce pollution and improve people's living conditions. Whether it is organic sewage treatment, urban garbage energy utilization or straw pyrolysis, it is an important point to solve the environmental pollution problem, which is also the primary goal of most biomass utilization.

5. Solve the problem of rural energy supply and improve the living standards of farmers.

China's rural energy supply is tight, and biomass energy is abundant. Developing and utilizing biomass energy is conducive to improving rural energy supply. Improve their living standards.

6. Improve the energy structure and reduce the environmental pressure. China can develop 700 million tons of biological resources. If fully developed, it can occupy an important position in China's energy consumption, which is of great significance for improving China's energy structure, reducing China's dependence on fossil fuels, further reducing the emissions of pollutants such as CO2 and SO2 in China, and finally alleviating the pressure on the environment caused by energy consumption.

3.3 Market demand

It can be predicted that with the development of national economy and the improvement of people's living standards, the market prospect of biomass energy utilization technologies and devices will be more and more broad. Main basis:

1. At present, most crop straws are burned in farmland because they cannot be effectively used, which not only wastes a lot of energy, but also causes serious environmental pollution, which has a certain negative impact on social life and economic development. For example, there have been smoke incidents in Chengdu Shuangliu Airport and Capital Airport. With the improvement of living standards, farmers who are getting richer urgently change their cooking and heating conditions by burning straw firewood directly. Using biomass combustible gas as living energy will improve their sanitary environment, improve their quality of life and reduce their labor intensity.

2. Many grain, wood, tea, fruit and other processing plants produce a large number of wastes such as chaff, sawdust, sawdust and fruit shells every day. Using biomass gasification technology to convert it into combustible gas to produce high-quality energy and turn waste into treasure can kill two birds with one stone.

3. Livestock manure is not only an extremely harmful environmental pollution source, but also an important biomass energy source. With the continuous construction and development of large livestock farms, environmental pollution is becoming more and more serious. Using anaerobic technology to treat livestock manure has more energy and environmental significance.

With the rapid development of China's social economy, the increase of urban population and the improvement of residents' lives, the problem of urban garbage disposal has become increasingly prominent. Take Beijing, China as an example. 1995 The annual garbage output has exceeded 4 million tons, and 1996 Beijing garbage reached 4.85 million tons. Using anaerobic technology to treat organic waste can not only obtain energy, but also achieve the goal of low-cost pollution control.

5. China's remote areas are rich in biomass resources, and most of them belong to areas lacking electricity. Biomass can be gasified to generate electricity or heat for personal use.

In fact, the advantage of biomass energy technology is that it can not only obtain inexhaustible energy, but also protect the environment and save resources.

3.4 Development Status and Problems of Biomass Energy Technology in China

Our government and relevant departments attach great importance to the utilization of biomass energy, and several major leaders of the country have repeatedly instructed and instructed to strengthen the energy utilization of crop straw. The State Science and Technology Commission listed the research and application of biomass energy technology as the key research project in the three five-year plans of the country, and a large number of outstanding scientific research achievements and successful application examples emerged, such as biogas digesters, livestock manure biogas technology, biomass gasification power generation, centralized gas supply, biomass briquette and so on. Considerable social and economic benefits have been achieved. At the same time, China has formed a high-level scientific research team including famous domestic scientific research institutes and universities, and has a group of famous experts and scholars who are enthusiastic about the research and development of biomass pyrolysis and gasification technology.

A. Biogas technology is the earliest biomass energy utilization technology in China. In 1970s, in order to solve the problem of energy shortage in rural areas, China vigorously developed and popularized household biogas digesters, and built 5.25 million household biogas digesters nationwide. In the recent three consecutive five-year plans, the state has listed the development of new biogas technology as a key scientific and technological project, and plans to implement a large number of research projects and demonstration projects on biogas and its utilization. Up to now, more than 30,000 large and medium-sized biogas digesters have been built in China, with a total volume of over 6,543.8+0.37 million m3 and an annual output of 55 million m3. There are more than 630 biogas projects with the scale exceeding 100m3, including 583 centralized gas supply stations with 83,000 users, with an average annual gas consumption of 43 1 m3, which are mainly used to treat livestock manure and organic wastewater. These projects have achieved certain environmental and social benefits and played a positive role in developing local economy and anaerobic technology in China. During the Ninth Five-Year Plan period, the high-efficiency anaerobic technology applied to the treatment of high-concentration organic wastewater and municipal solid waste was listed as key scientific and technological projects, which were undertaken and implemented by Chengdu Institute of Biology of China Academy of Sciences and Hangzhou Institute of Energy and Environment respectively, and expected progress was made.

The main problems of anaerobic technology and engineering in China are: little research on related technologies, poor matching of auxiliary equipment, low degree of automation, rough processing of non-standard equipment, high project cost, serious secondary pollution of open pretreatment and post-treatment, etc.

B in recent years, great progress has been made in biomass gasification technology in China. The forms of gasifier range from traditional up-draft and down-draft to the most advanced fluidized bed, fast fluidized bed and double-bed system. Besides traditional heating, the most important breakthrough in application is rural household gas supply and gasification power generation. During the "Eighth Five-Year Plan" period, the State Science and Technology Commission arranged the scientific and technological research topic of "Biomass Pyrolysis Gasification and Heat Utilization Technology", and achieved considerable results: (1) A biomass gasification device with medium calorific value was successfully developed by using oxygen gasification process; Downdraft fluidized bed process was used to successfully develop 100 household biomass gasification centralized gas supply system and device; downdraft fixed bed process was used to successfully develop biomass gasification drying system and device for grain and cash crops; Using fluidized bed dry distillation process, 65,438+0,000 household centralized gas supply systems and devices for biomass gasification were successfully developed. During the Ninth Five-Year Plan period, the State Science and Technology Commission arranged the scientific research topic of "Biomass Pyrolysis and Gasification and Related Technologies", focusing on the research and development of 1MW large-scale biomass gasification power generation technology and rural straw gasification centralized gas supply technology. At present, more than 200 rural gasification stations have been built in China, and more than 0/00 rice husk gasification power generation units have been built. The influence of gasification technology is gradually expanding.

C. During the Eighth Five-Year Plan period, China began to explore and study the technology of producing ethanol fuel from cellulose waste, mainly studying the dilute acid hydrolysis and fermentation technology of cellulose waste, and entered the intermediate test stage during the Ninth Five-Year Plan period. Our country has made a preliminary study on alternative fuels such as vegetable oil and biomass pyrolysis oil, such as physical and chemical characteristics of vegetable oil, esterification modification process, combustion performance of diesel engine, etc. During the Ninth Five-Year Plan period, the classified investigation of wild oil plants and the construction of breeding bases were carried out. There are some studies on biomass liquefaction in China, but the technology is relatively backward, mainly high-pressure liquefaction and pyrolysis liquefaction.

D. In addition, during the Eighth Five-Year Plan period, China also focused on tackling key problems of biomass compression molding technology, introduced advanced foreign models, digested and absorbed them, and developed various biomass compression molding machines suitable for China's national conditions to produce rod, block or granular biomass molding fuel. The service life of the screw of biomass screw forming machine in China is over 500 hours, which belongs to the international advanced level.

Although China has made great achievements in developing biomass energy, there is still a certain gap in technical level compared with developed countries, such as:

A. the development of new technologies is weak and the use of technologies is single. In China, early biomass utilization mainly focused on biogas utilization. In recent years, the development and application of pyrolysis and gasification technology have been paid more and more attention, and some breakthroughs have been made. However, the development of other technologies is very slow, including industrial technologies such as alcohol production, pyrolysis and liquefaction, direct combustion and cultivation of fast-growing forests, and there is no breakthrough.

B due to scattered resources and backward collection methods, the scale of biomass energy utilization projects in China is very small; In order to reduce investment, most projects use simple technology and simple equipment, which has low equipment utilization rate and low conversion efficiency. Therefore, biomass energy projects have low return on investment and high operating costs, and it is difficult to form economies of scale and cannot play its due significant energy role.

C. Compared with the scientific research content, the investment is too little, which makes the technical content of the research low, mostly low-level repetitive research, and finally fails to solve some key technologies, such as low biogas production rate of anaerobic digestion and poor automation degree of equipment and management; The tar problem in gasification utilization has not been completely solved, which brings serious problems to long-term application; The efficiency of biogas power generation and gasification power generation is low, and the corresponding secondary pollution problem has not been completely solved Therefore, many engineering systems are often in a state of maintenance or failure, which reduces the operation intensity and efficiency of the system.

In addition, in the realistic social and economic environment of China, there are still some negative factors that restrict or hinder the development, popularization and application of biomass energy utilization technology, mainly as follows:

A. Under the current energy price conditions, biomass energy products lack market competitiveness, and the low return on investment has dampened investors' investment enthusiasm, while the high sales price has dampened consumers' enthusiasm.

B. the technical standards are not standardized and the market management is chaotic. Due to the lack of corresponding technical standards and strict technical supervision, many units and individuals who do not have the technical strength participated in the biogas project contracting and the production of straw gasification gas supply equipment, which led to the failure of engineering technology, failed to achieve the expected goal, and even brought security problems, which brought great negative impact on the future utilization of biomass.

C. At present, it is not feasible to support the development of biomass energy, and governments at all levels should formulate relevant policies as soon as possible, such as price subsidies and special preferential policies for power generation.

D people don't know enough about biomass energy, so the publicity and popularization of common sense should be strengthened.

E the government should pay full attention to the strategic position of biomass energy. Developing biomass energy is a systematic project, which should be regarded as the basic construction project to realize sustainable development.

4. Development direction and countermeasures

4. 1 development direction

China is rich in biomass energy resources and low in price, but its economic environment and development level are in a favorable stage of developing biomass technology. According to these characteristics, the development of biomass in China should not only learn from foreign advanced experience, but also highlight its own characteristics. Therefore, the future development direction should be in the following aspects:

A further give full play to the role of biomass energy as supplementary energy in rural areas, provide clean energy for rural areas, improve rural living environment and improve people's living standards. Including biogas utilization, straw gas supply, small gasification power generation and other practical technologies.

B strengthen the industrialized application of biomass, increase the proportion of biomass energy utilization, and improve the status of biomass energy in the energy field. Only in this way can we fundamentally expand the influence of biomass energy and create conditions for its large-scale application in the future, which is also the key to whether biomass energy can become an important alternative energy source in the future.

C. study the technology of transforming substances into high-grade energy products to improve the utilization value of biomass energy. This is an important technical reserve, the basis of multi-channel utilization of biomass in the future, and the key to improve the role and status of biomass energy in the future.

D. At the same time, develop new biomass energy in mountainous areas, wasteland and desert, research, cultivate and develop fast-growing and high-yield plant varieties, develop energy farms and forest farms in areas where current conditions permit, establish biomass energy bases, and provide large-scale energy resources such as wood or vegetable oil.

4.2 Countermeasures

According to the above main development directions, whether the biomass utilization technology in China can develop rapidly in the future mainly depends on the following aspects:

A. Industrialization: strengthen the commercialization of biomass utilization technology, formulate strict technical standards, strengthen technical supervision and market management, standardize market activities, and create a good market environment for biomass technology promotion.

B. In terms of industrial production and large-scale application: strengthen the connection between biomass technology and industrial production, and solve the key technologies in demonstration application. In technical research, we not only pay attention to solving technical problems in popularization and application, but also improve and test the reliability and economy of biomass energy technology in production practice, thus creating conditions for large-scale utilization of biomass.

C. In terms of technical research, we should not only focus on solving technical problems in popularization and application, such as tar treatment and biogas technology in cold areas, but also explore new technologies for biomass utilization, such as advanced technologies such as biomass oil production and biomass oxygen production.

Formulate the national development plan of biomass energy, introduce new technologies and new processes, demonstrate, develop and popularize them, and make full and rational use of biomass energy resources. 2 1 century, some fossil fuels will be gradually replaced by high-quality biomass energy products (solid fuel, liquid fuel, combustible gas, electricity, electric energy, etc.). ) to solve the problems of energy shortage and environmental pollution in China.

4.3 Priority areas

Straw energy utilization

Organic waste treatment and energy utilization

Industrial organic waste residue and wastewater treatment and energy utilization

biomass liquid fuel

4.4 Main key technologies

Efficient biomass gasification power generation technology

IGCC organic waste power generation technology

Efficient anaerobic treatment and biogas recovery technology

Cellulose alcohol production technology

Biomass pyrolysis liquefaction technology

Cultivation and utilization technology of energy plants

5. Conclusion

Biomass energy will become an important part of sustainable energy in the next century. China has a vast territory, but the fossil energy resources are limited and the biomass resources are abundant, so it is of great strategic and practical significance to develop biomass energy. Using high technology to convert biomass such as straw, livestock manure and organic wastewater into high-grade energy, developing biomass energy will involve many interests such as rural development, energy development, environmental protection, resource protection, national security, ecological balance and so on. I hope to get extensive attention and support from all walks of life, governments at all levels, experts and scholars, and create a favorable development environment for the biomass energy industry in China.

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