biomass energy

Energy provided by living plants in nature

Collection

zero Useful+1

zero

This entry is made by Compilation and application of scientific encyclopedia entries of "Science Popularization China" to examine.

Biomass energy is the energy provided by living plants in nature. These plants use biomass as a medium to store solar energy, which is renewable energy. According to calculations, the energy stored by biomass is twice the total energy consumption of the world. Biomass energy is the earliest energy used in human history. Before the second half of the 19th century, firewood was the main energy used by human beings. At present, the more effective ways to use biomass energy are: (1) biogas production. It mainly uses urban and rural organic waste, straw, water, human and livestock manure to produce combustible gas methane through anaerobic digestion for domestic and production purposes. (2) Use biomass to produce alcohol. In the current world energy structure, biomass energy accounts for very little.^[1]

Chinese name: biomass energy
Foreign name: biomass energy
Category: Energy

Meaning: Solar energy is stored in biomass as chemical energy
Media: biomass
Nature: Renewable energy
Purpose: Producing alcohol and biogas from biomass

catalog

brief introduction

Announce

edit

Biomass energy can be converted into conventional solid, liquid and gaseous fuels, which are inexhaustible renewable energy It is also the only renewable carbon source.

Biomass characteristics

Announce

edit

Biomass refers to the utilization of air water , land and other organisms produced through photosynthesis, that is, all living and growing organic substances are collectively referred to as biomass. It includes plants, animals and microorganisms. Broad concept: biomass includes all plants, microorganisms, animals that feed on plants and microorganisms, and the waste produced by them. Representative biomass such as crops, crop waste, wood, wood waste and animal manure. In a narrow sense, biomass mainly refers to the lignocellulose (lignin for short), such as straw and trees, except grain and fruit Agricultural product processing industry Leftovers Agricultural and forestry wastes And livestock manure and wastes in the production process of animal husbandry. Features: renewable, low pollution, widely distributed.

Analysis on the characteristics of China's biomass energy in 2013: ① renewable. Biomass energy is converted from solar energy, which is converted into chemical energy through photosynthesis of plants. The energy stored in biomass, like wind energy and solar energy, belongs to renewable energy, which can realize the sustainable use of energy.

② Clean and low-carbon. The content of harmful substances in biomass energy is very low, which is clean energy 。 At the same time, the conversion process of biomass energy is through the photosynthesis of green plants carbon dioxide And water to synthesize biomass, and the use of biomass energy generates carbon dioxide and water, forming a cycle of carbon dioxide emissions, which can effectively reduce the net emissions of human carbon dioxide and reduce the greenhouse effect.

③ Alternative advantages. Modern technology can be used to convert biomass energy into alternative fossil fuels Biomass briquette fuel , biomass combustible gas, biomass liquid fuel, etc. In terms of thermal conversion, biomass energy can be directly burned or converted to form solid, gas and liquid fuels that are easy to store and transport, and can be used for most of the oil, coal and natural gas industrial boiler And kiln. According to the Energy Report released by the International Natural Fund in February 2011, 60% of industrial fuels and industrial heating will use biomass energy by 2050.

④ Rich raw materials. Biomass energy resources are abundant and widely distributed. according to WWF It is estimated that the potential available amount of global biomass energy will reach 350EJ/year (about 8.212 billion tons of standard oil, equivalent to 73% of global energy consumption in 2009). According to the statistics of China's Medium and Long term Development Plan for Renewable Energy, the potential of biomass resources to be converted into energy is about 500 million tons of standard coal. With the expansion of afforestation area and the development of economy and society, the potential of biomass resources to be converted into energy in China can reach 1 billion tons of standard coal. In the context of the gradual depletion of traditional energy, biomass energy is an ideal alternative energy, known as the "fourth largest" energy after coal, oil and natural gas.

biomass

Announce

edit

Fat fuel speedboat

biomass It refers to various forms formed by photosynthesis Organism , including all animals, plants and microorganisms. The so-called biomass energy is solar energy chemical energy Form The form of energy stored in biomass, that is, the energy carried by biomass. It comes directly or indirectly from Green plants It can be converted into conventional solid, liquid and gaseous fuels, inexhaustible renewable energy It is also the only renewable carbon source. The original energy of biomass energy comes from the sun, so in a broad sense, biomass energy is a form of solar energy. Many countries are actively researching, developing and utilizing biomass energy. Biomass energy is contained in plants, animals, microorganisms and other organic matter that can grow. It is converted from solar energy. In organic matter, all energy materials from animals and plants except fossil fuels belong to biomass energy, usually including wood, forest waste Agricultural Waste , aquatic plants, oil plants, urban and industrial organic wastes, animal manure, etc. Terrestrial Biomass energy resources It is abundant and a harmless energy source. Every year, the earth produces 173 billion tons of material through photosynthesis, which contains energy 10-20 times of the total energy consumption of the world, and the utilization rate is less than 3%.

classification

Announce

edit

According to different sources, biomass suitable for energy utilization can be divided into five categories: forestry resources, agricultural resources, domestic sewage and industrial organic wastewater, urban solid waste and livestock manure.

Forestry resources

biomass energy

Forestry biomass resources refer to biomass energy provided by forest growth and forestry production, including firewood forest, scattered wood in forest tending and thinning operations, residual branches, leaves and sawdust; Branches, sawdust, sawdust, shoots, barks and stumps in the process of wood collection, transportation and processing; Wastes of forestry by-products, such as shells and nuts.

agricultural resource

Agricultural biomass energy resources refer to agricultural crops (including Energy crops )； Wastes during agricultural production, such as crop straws (corn straw, sorghum straw, wheat straw, rice straw, soybean straw cotton stalk Etc.); Wastes from agricultural processing industry, such as rice husks left over during agricultural production. Energy plants generally refer to various plants used to provide energy, usually including herbaceous energy crops Oil crops , hydrocarbon production plants and aquatic plant And so on.

Sewage and wastewater

domestic sewage It is mainly composed of various drainage of urban residents' living, business and service industries, such as cooling water, bath drainage, toilet drainage, laundry drainage, kitchen drainage, fecal sewage, etc. Industrial organic wastewater is mainly the wastewater discharged in the production process of alcohol, wine making, sugar making, food, pharmacy, paper making, slaughtering and other industries, which is rich in organic matter.

solid waste

The urban solid waste is mainly composed of urban residents' domestic waste, commercial and service waste, and a small amount of construction waste and other solid waste. Its composition is relatively complex, which is affected by the average living standard of local residents energy consumption structure , urban construction, natural conditions, traditional habits, seasonal changes and other factors.

livestock manure

livestock manure It is the general term of livestock and poultry excreta, and it is other forms of biomass (mainly grain, crop straw and forage grass And so on), including feces and urine discharged by livestock and poultry and their mixture with bedding grass.

methane

methane It is a kind of biomass energy conversion combustible gas 。 Biogas is a mixture, and its main component is methane (CH4). Biogas is a kind of mixed gas produced by organic substances under anaerobic conditions through microbial fermentation. Since this gas was first found in marshes, it is called biogas. Human and livestock manure, straw, sewage and other organics are stored in closed biogas digesters anaerobic Fermentation under (no oxygen) conditions, various microorganisms of biogas fermentation Decomposition and conversion to produce biogas. Biogas is a mixed gas that can be burned. It can usually be used for cooking and lighting by farmers.

characteristic

Announce

edit

Renewable

Biomass energy is a renewable resource. Biomass energy can be regenerated through plant photosynthesis Wind energy , solar energy equivalent renewable energy Abundant resources can ensure the sustainable use of energy;

Low pollution

The sulfur content and nitrogen content of biomass are low, and the SOX and NOX generated during combustion are less; When biomass is used as fuel, because the carbon dioxide it needs for growth is equal to the amount of carbon dioxide it emits, the net carbon dioxide emissions to the atmosphere are approximately zero, which can effectively reduce greenhouse effect ；

Wide distribution

In regions lacking coal, biomass energy can be fully utilized;

The total amount is very rich

Biomass energy is the fourth largest energy in the world, second only to coal, oil and natural gas. According to biologists' estimates, the earth's land produces 100 to 125 billion tons of biomass every year; Ocean produces 50 billion tons of biomass annually. The annual production of biomass energy far exceeds the total energy demand of the world, equivalent to 10 times the total energy consumption of the world. China's biomass resources that can be developed as energy will reach 300 million tons by 2010. With the development of agriculture and forestry, especially the promotion of carbon fuel forest, biomass resources will be more and more.

Wide application

Biomass energy can be formed by biogas and compression solid fuel Gasification production gas, gasification power generation, production Fuel alcohol Thermal cracking production biodiesel It is used in various fields of the national economy.

utilize

Announce

edit

Gasification and combustion boiler

Biomass energy has always been an important energy source for human survival. It is second only to coal, oil and natural gas and occupies the world Total energy consumption The fourth energy plays an important role in the whole energy system. Experts estimate that biomass energy is likely to become the future Sustainable energy As part of the system, by the middle of the next century, various biomass alternative fuels produced by new technologies will account for more than 40% of the global total energy consumption.

The utilization of biomass energy by human beings, including straw and firewood of crops directly used as fuel; Indirect fuels include agricultural and forestry wastes, animal excrement, garbage and algae, which are generated by microbial action methane , or use pyrolysis method to produce liquid and gaseous fuel , can also be manufactured Biochar 。 Biomass energy is the most extensive renewable energy in the world. It is estimated that the total biomass generated by photosynthesis alone on the earth each year amounts to 144-180 billion tons (dry weight), and its energy is about 3 to 8 times of the total energy consumption of the world in the early 1990s. However, it has not been used reasonably by people, and most of it is directly used as firewood, which is inefficient and affects the ecological environment. Modern biomass energy is used through biomass anaerobic fermentation To produce methane, to generate fuel gas, bio oil and biochar by pyrolysis, to produce ethanol and methanol fuel from biomass, and to utilize bioengineering technology Cultivate energy plants and develop them Energy farm 。

Ways of utilization

Biomass energy wood compressed particles

The utilization of biomass energy mainly includes direct combustion Thermochemistry Conversion and biochemical conversion. The direct combustion of biomass will still be the main way of biomass energy utilization in China for a long time to come. Current modification thermal efficiency The traditional wood burning stoves, which only account for about 10%, and the promotion efficiency of wood saving stoves, which are simple in technology, easy to promote, and have obvious benefits, are listed as one of the key tasks of rural new energy construction by the state. Thermochemical conversion of biomass refers to the technology of vaporization, carbonization, pyrolysis and catalytic liquefaction of biomass under certain temperature and conditions to produce gaseous fuel, liquid fuel and chemical substances. Biochemical conversion of biomass includes biomass biogas conversion and biomass ethanol conversion. Biogas conversion is Organic matter In an anaerobic environment, by Microbial fermentation Produce a kind of combustibility with methane as the main component mixed gas That is biogas. Ethanol conversion is to use sugar, starch, cellulose and other raw materials to produce ethanol through fermentation.

Utilization status

By the end of 2006 (1898), 18.7 million rural household biogas digesters, 140000 biogas digesters for domestic sewage purification, more than 2000 livestock and poultry farms and industrial wastewater biogas projects had been built nationwide, with an annual biogas production of about 9 billion cubic meters, providing high-quality domestic fuel for nearly 80 million rural people.

China has developed a variety of fixed bed And a fluidized bed gasifier, which uses straw, sawdust, rice husk and tree branches as raw materials to produce gas. In 2006, more than 800 sets were used for drying wood and agricultural and sideline products at the village and town level Straw gasification Centralized gas supply system Nearly 600 sites, with an annual production of 20 million cubic meters of biomass gas.

The development of biomass energy focuses on solving the "five difficulties"

Faced with the global situation of reducing fossil energy consumption and controlling greenhouse gas emissions, using biomass energy resources to produce renewable energy products that can replace fossil energy has become one of the important ways for China to cope with global warming and control greenhouse gas emissions, Biomass power generation will reach the goal of 13 million kilowatts. However, due to the difficulty in collecting raw materials and insufficient policy subsidies, the development scale and level of the biomass energy industry is far lower than the utilization of wind and solar energy. How to give play to the production enthusiasm of biomass energy enterprises and solve these problems as soon as possible? To this end, the reporter interviewed Xiao Mingsong, Secretary General of Biomass Special Committee of China Rural Energy Industry Association, Energy Research Institute of National Development and Reform Commission researcher Qin Shiping Professor Yuan Zhenhong, Secretary General of Biomass Energy Professional Committee of Renewable Energy Society.^[2]

One difficulty: insufficient understanding

Biomass energy is in an awkward situation. Qin Shiping, a researcher from the Energy Research Institute of the National Development and Reform Commission, told our reporter frankly: "It is important to say that biomass energy is the most important among renewable energy, but in comparison, its industrialization and development scale are the worst. There are some objective reasons, but also some problems of understanding."^[2]

The importance of biomass energy is reflected in the following four points. Qin Shiping introduced: First, China is a country with less land and more people. Agricultural and forestry residues, urban garbage and other wastes are the main sources of biomass resources. In the past, farmers used to treat straw with a fire, while urban garbage is mostly landfill, but waste treatment is a rigid demand, With the improvement of the national CO2 emission limit, the energy utilization of biomass has become a more advanced and effective method; Second, China is short of fossil energy, of which liquid fuel is the most scarce, and liquid fuel can only be converted by using biomass; Third, all production stages of biomass energy can be artificially intervened, while wind energy and solar energy can only rely on the sky. Power generation must cooperate with peak shaving, while biomass energy is not needed, and it can even provide peak shaving for other energy sources; Fourthly, biomass raw materials need to be collected, which can increase farmers' income, stimulate local consumption, and effectively promote the development of rural economy. For a power plant with a capacity of 25 million to 30 million kilowatts, farmers will get about 50 million to 60 million yuan in material collection. If the problem of "agriculture, countryside and farmers" is solved, it will play a very important role in the development of the whole society.^[2]

In addition to the limited development scale objectively, Qin Shiping believed that: the understanding of biomass energy is different, and the amount of investment is inconsistent with the local GDP growth. The dispersion of resources leads to the investment of biomass energy in one place, which is more than 200 million at most; In the view of some government officials, biomass energy is a bit like "chicken ribs". It is a pity that some people can not eat enough and lose it. In addition, local governments should help coordinate the interests of farmers, ban burning and other "troublesome things". As a result, the overall project scale of biomass energy is small and the technology investment is insufficient. Although it is good for the country and farmers, it is in an awkward position of poor development.^[2]

Yuan Zhenhong, secretary-general of the Biomass Energy Professional Committee of the Renewable Energy Society, also told reporters by telephone that compared with traditional energy such as coal, oil and natural gas, the investment in technology of biomass energy is obviously much lower. For the development of biomass energy, first of all, we should unify our thinking from the top, improve our understanding of the importance of biomass energy, and increase investment in technology.^[2]

The second difficulty: the subsidy threshold is too high

For the support of biomass energy, the state has adopted a variety of subsidies. However, many enterprises are also troubled by the high threshold of subsidies, cumbersome procedures, advance payment before subsidies. According to the document CJ [2008] No. 735 issued by the Ministry of Finance, only when the registered capital of an enterprise is more than 10 million yuan and the annual straw consumption is more than 10000 tons, can the enterprise be eligible for a subsidy of 140 yuan/ton. In this regard, Xiao Mingsong, secretary-general of the Biomass Special Committee of China Rural Energy Industry Association, believes that a registered capital of 10 million yuan is a necessary means for the state to consider preventing business risks, which does not matter to large enterprises, but is difficult for some small and medium-sized companies to achieve. However, the annual consumption of 10000 tons of straw requires a considerable storage site. The fire hazard and cost increase caused by this need are also issues that enterprises have to consider. In fact, if the drum excitation surface is expanded, three or five thousand tons is also applicable. Restricted by these practical problems, the ten thousand ton subsidy policy of the Ministry of Finance is difficult to implement.^[2]

Qin Shiping, who participated in the formulation of the national subsidy policy, explained that the original intention of the national policy formulation was not to encourage biomass energy enterprises to adopt simple practices and flourish everywhere, but to encourage enterprises to specialize in biomass energy and cultivate backbone enterprises, which requires a certain material foundation. For a 10000 ton factory, the fixed assets will need about 4 million yuan. With the working capital, 10 million yuan is not much. In terms of energy utilization, the 10000 ton scale is just a bit of scale. As long as it is the same owner, the production points can be scattered. If the scale is too small, the cost of subsidies and supervision is too high. As for the way of subsidy, Qin Shiping acknowledged that there were some defects, and the whole mechanism lacked the participation of the competent energy department and the technical department. How can the system be more conducive to supervision, fairness and openness still need to be further improved. The rapid development of the industry has been attributed to the subsidy policy. However, we should not cancel the subsidy policy because of some problems, which will cause a major blow to the fledgling biomass energy utilization industry. Because the state subsidy not only provides funds, but also shows the state's support attitude towards the industry and has a strong guiding role for enterprises and investment.

In addition, fixed electricity price is also an important part of subsidies. Biomass power generation is 0.75 yuan/kWh, garbage and methane Power generation is 0.65 yuan/kilowatt hour. VAT is levied and refunded immediately, and income tax is calculated at 90% of sales revenue. Yuan Zhenhong pointed out that the government encouraged production, there was no market after production, and the industry still could not develop. Therefore, both producers and users should be encouraged to open up markets for enterprises. Only when the industry develops can the country have policies. Conversely, if the policy is not given, the enterprise can hardly have a market.^[2]

Three difficulties: Bad layout will suffer losses

How much capacity should the enterprise build? Qin Shiping often met with the person in charge of an enterprise who asked him for advice.

"There is no best, only the best, and the best is the best. For example, if there is only a few points of land for each person in southern Jiangsu, there is no way to collect, and there is no way to build large plants in these places, but the Northeast Reclamation Area is more suitable for building large power plants. The lower the cost is, the higher the benefit will be. We must adjust measures to local conditions. In dense areas, gasification can be built for power generation, and it is not necessary to build power plants. "

Xiao Mingsong also suggested that enterprises should consider all aspects and make rational layout, otherwise they would easily fall into development dilemma. To build a biomass power plant, we should first consider sustainable development, decentralized use of raw materials, and whether water resources, electricity, and human environment can support this project.^[2]

Four difficulties: difficult to control cost price

Restricted by the farming system, the rural land in China is highly dispersed, and the collection, storage and transportation of resources will bring great adverse factors, which will be magnified many times in the subsequent links. "Some people think that the expansion of the collection radius is just an extra fuel money. In fact, the transportation means and labor costs are different." Qin Shiping explained that, "The biomass power plant with an installed capacity of 30000 kilowatts needs about 250000 to 300000 tons of straw a year. If the average household of 10 mu of arable land in China is calculated, it needs about 200000 farmers to complete the project. Then you need to take scales with you when purchasing, and 200000 tickets are needed for all. You need to load vehicles one by one, which cannot achieve efficient mechanization."

Xiao Mingsong also understood the suffering of enterprises very well. "Biomass energy depends on agriculture, resources are in the hands of the people, farmers have a good sense of the market, and completely follow the market. If the collection radius is too large, farmers need to spend a lot of time to collect and transport, then farmers will ask to calculate the labor cost according to the time they go out to work, so that the cost of raw materials spent by enterprises will be greatly increased. If the enterprise insists on not raising the price, it may cause the enterprise to be short of food, shrink production and affect economic benefits. If the cost of raw materials per kilowatt hour exceeds a certain range, no matter how power is generated, it will be a loss. With the rapid increase of labor costs in recent years, costs have become a shackle around the neck of enterprises. "^[2]

"Therefore, the first thing for enterprises to consider is the availability of raw materials. If they are not mature, they should not rush into the industry." Xiao Mingsong believes that local governments can coordinate, such as using the demonstration effect to encourage farmers to plant straw crops, doing a good job in the combination of enterprises and farmers, and balancing the interests of enterprises and farmers.^[2]

Five difficulties: small technology investment

"There is a certain gap between China's biomass energy technology and that of foreign countries, but technology and national subsidies can maintain industrialized operation. Technological progress is endless, foreign technology and equipment costs are too high for us, cars are high in science and technology, but if you go to farmland, it is not as good as tractors." Qin Shiping smiled and compared to reporters. Scientific research departments are doing front-end research every year, and the efforts are not very strong. From laboratory to field to large-scale production of industrial enterprises, technological innovation takes a long time. Enterprises can explore while producing.

"The problem is that some research results are somewhat disconnected from production, and have not been transformed into productivity and promoted to the society." Xiao Mingsong said that, on the one hand, the technology department is unable to carry out large-scale production due to lack of funds, and on the other hand, in order to recover technology costs as much as possible, the enterprise intends to lengthen the cycle of new technology introduction to the market. "However, what we are facing now is an international market. If we hold on to the old technology, once a new technology is put on the market, the enterprise will always face low efficiency, which is difficult to maintain."

"The technology input of biomass energy is still very small. From a macro perspective, the existing energy has not been exhausted. Monopolies control some energy terminals, and also limit the technology input of small and medium-sized enterprises. If PetroChina invests in biomass energy, it is easy to produce ethanol gasoline, because fuel ethanol is added to gasoline according to the standard requirements to form ethanol gasoline, which can be controlled by others throughout the industry chain. When the big energy is still sustainable, we will not put too much effort on biomass energy. " In addition, international oil, coal and natural gas prices have a linkage relationship. When their prices approach the prices of biomass energy products, enterprises will have more profits. When fossil energy resources are exhausted to a certain extent, the advantages of biomass energy will be reflected.^[2]

Utilize technology

1. Direct combustion

The research and development of biomass direct combustion and solidification molding technology mainly focuses on the design of special combustion equipment and the application of biomass briquettes. The molding technologies that have been successfully developed can be divided into three main categories according to the shape of the molded products: the spiral extrusion technology to produce bar shaped shaped products developed by Japan as a representative, the piston extrusion cylindrical block molding technology developed by European countries, and the internal pressure roller granular molding technology and equipment developed and researched by the United States.

2. Biomass gasification

Biomass gasification technology It is to put solid biomass in the gasifier for heating, and at the same time, air oxygen or steam To produce high grade combustible gas. It is characterized by gasification rate of more than 70% and thermal efficiency of 85%. Biomass gasification Combustible gas After treatment, it can be used for synthesis, heating, power generation and other different purposes, which is of great significance for remote mountain areas with abundant biomass materials. It can not only change their quality of life, but also improve energy efficiency and save energy.

3. Liquid biofuel

Liquid fuels made from biomass are called biofuels. Biofuels mainly include Bioethanol , bio butanol, bio diesel, bio methanol, etc. Although the use of biomass to make liquid fuel started early, it has developed slowly oil resources Since the 1970s, many countries have increasingly attached importance to the development of biofuels and achieved remarkable results.

four methane

Biogas is produced when various organic substances are isolated from the air (reduced) and under suitable temperature and humidity conditions Fermentation A combustible gas produced. Methane, the main component of biogas, is similar to natural gas and is an ideal gaseous fuel. It is colorless and odorless, and can be burned after mixing with appropriate amount of air.

1) Traditional and comprehensive utilization technology of biogas

China is a country that develops more biogas in the world. At first, it was mainly rural household biogas digesters to solve the problem of straw burning and insufficient fuel supply. Later, large and medium-sized biogas projects began in 1936. Since then, the establishment of large and medium-sized wastewater, aquaculture wastewater, village and town biomass waste, and urban garbage biogas has widened the scope of biogas production and use.

Since the 1980s Biogas fermentation Comprehensive utilization technology, an efficient agricultural model with biogas as the link, multi-level utilization of materials and rational flow of energy, has gradually become an effective way to promote sustainable development by using biogas technology in rural areas of China. Through biogas fermentation comprehensive utilization technology, biogas is used for household energy consumption and agricultural by-product production and processing, and biogas slurry is used for feed Biopesticide The production of culture liquid, the use of biogas residue for fertilizer production, the "four in one" biogas ecological agriculture model of combining plastic greenhouses, biogas digesters, gas poultry houses and toilets promoted in the north of China, and the biogas as the link in the central region Ecological orchard The "pig fruit" model established in the south, as well as the "breeding biogas", "pig biogas fish" and "grass cattle biogas" models established in other regions according to local conditions, are all ecological agricultural models with agriculture as the leader and biogas as the link, and the multi-level utilization of biogas, biogas slurry and biogas residue. The establishment of biogas fermentation comprehensive utilization ecological agriculture mode makes rural biogas and agricultural ecology closely combined, which is an effective measure to improve rural environmental health, and an effective way to develop green planting and breeding industry, and has become a new growth point of rural economy.

2) Biogas power generation technology

methane With the continuous development of large-scale biogas digester construction and biogas comprehensive utilization, a biogas utilization technology for combustion power generation will anaerobic fermentation The treated biogas is used on the engine and is equipped with a comprehensive power generation device to generate electric energy and heat energy. Biogas power generation has the characteristics of high efficiency, energy saving, safety and environmental protection. It is a widely distributed and inexpensive distributed energy. Biogas power generation has received extensive attention and actively promoted in developed countries. The grid connected electricity generated by biomass energy accounts for about 10% of the total energy in some Western European countries.

3) Biogas fuel cell technology

Fuel cell is a device that directly converts chemical energy stored in fuel and oxidant into electrical energy. When fuel and oxidant are continuously supplied to the fuel cell from outside, it can generate electricity continuously. basis electrolyte The fuel cell is divided into Alkaline fuel cell (AFC), proton exchange membrane (PEMFC), phosphoric acid (PAFC), dissolved carbonate (MCFC) and solid oxide (SOFC), etc.

Fuel cell energy conversion efficiency is high, clean, pollution-free, and low noise. It can be used for centralized power supply or decentralized power supply. It is one of the most competitive efficient and clean power generation methods in the 21st century Uninterruptible power supply , submarines and space power supply have a broad application prospect and huge potential market.

five Biological hydrogen production

Hydrogen is a kind of clean and efficient energy, which has a wide range of industrial uses and huge potential. In the future, biological hydrogen production has gradually become a hot topic of attention, but it is not easy to convert other substances into hydrogen. The biological hydrogen production process can be divided into two categories: anaerobic photosynthetic hydrogen production and anaerobic fermentation hydrogen production.

6. Biomass power generation technology

Biomass power generation technology is a technology that converts biomass energy into electricity, mainly including agricultural and forestry waste power generation, garbage power generation and biogas power generation. As a kind of renewable energy, biomass power generation has been paid more and more attention internationally, and in China, it has also received more and more attention from the government and support from the people.

Biomass power generation collects, processes and arranges waste agricultural and forestry residues to form commodities, and prevents environmental pollution caused by straw burning in the field. It also changes the appearance of rural villages. It is one of the energy strategic choices for China to build ecological civilization and achieve sustainable development. If China's biomass energy utilization reaches 500 million tons of standard coal, it can solve more than 20% of China's energy consumption and reduce the carbon emission of carbon dioxide by nearly 350 million tons, sulfur dioxide nitrogen oxide The emission reduction of smoke and dust is nearly 25 million tons, which will produce huge environmental benefits. More importantly, China's biomass energy resources are mainly concentrated in rural areas. Vigorously developing and utilizing the abundant biomass energy resources in rural areas can promote the development of rural production, significantly improve the rural appearance and living conditions of residents, and will contribute to the construction of New socialist countryside Have a positive and far-reaching impact.^[3]

7. Primary battery

The primary battery is made by transferring electrons during chemical reaction. The product is the same as that of direct combustion, but the energy can be fully utilized.

New utilization

Fat fuel speedboat

New Zealand amateur navigator and environmentalist Peter Bethune announced that he would drive the fat powered speedboat "Earth Race" for a round the world voyage. It is reported that Bethune will set out from Valencia, Spain, on March 1, 2008, and start a round the world voyage with a total length of about 45000 kilometers. Bethune said that he intended to challenge the world record of 75 day round the world voyage set by the British ship "Wired and Wireless Adventure" in 1998.

Fat as fuel "Earth Race" is known as the fastest ecological ship in the world, with a cost of 2.4 million dollars and a combination of many high-tech. The Earth Race is about 23.8 meters long and looks like a swan spreading its wings. The hull is protected by three layers of shells, with two advanced engines inside. The maximum speed can reach 40 knots per hour (about 74 km). Even when sailing in huge waves, the speed will not slow down.

Although there are many kinds of animal fats, Bethune plans to use only human fats Biofuels As the power source of the "Earth Race", 100% biofuels are used to complete an environmental journey around the world.

In order to raise enough fat biofuels, Bethune took the lead and took the initiative to lie on the operating table. However, despite the great efforts of plastic surgeons, the fat extracted from his body is only enough to produce 100 milliliters of biofuel. The 10 liters of fat extracted by his two assistants can be made into 7 liters of biofuel, which can be used for the Earth Race to sail 15 kilometers.

Pitt went on a "green" round the world tour to break the 75 day round the world record set by the British "wired and wireless adventurer" in 1998. A total of 70000 liters of biofuel was needed, that is, Pitt needed fat volunteers to donate about 70000 kilograms of fat.

resources

Announce

edit

Forest energy

Forest energy is the biomass energy provided by forest growth and forestry production process, mainly fuel wood, but also some residues of forest industry. Forest energy plays an important role in China's rural energy. Around 1980, the country's rural consumption of forest energy was about 100 million tons of standard coal, accounting for more than 30% of the total rural energy consumption. In hilly, mountainous and forest areas, more than 50% of rural domestic energy consumption depended on forest energy.

Fuel wood comes from branches pruned during the growth of trees, leftovers from wood processing, and fuel forests that provide fuel wood specifically. In 1979, 88.85 million tons of fuelwood were reasonably provided nationwide, and 181 million tons were actually consumed, more than double the amount of fuelwood; In 1995, it was reasonable to provide 143.229 million tons of forest energy, including more than 20 million tons of fuel wood for firewood forest, 213.39 million tons of rural consumption nationwide, and about 70 million tons of supply and demand gap.

Crop straw

Crop straw is not only a by-product of agricultural production, but also a traditional fuel in China's rural areas. Straw resources are closely related to agriculture, mainly crop production. According to the statistical data in 1995, the annual output of crop stalks in China is 604 million tons, of which fertilizer returning and collection losses account for about 15%, and the remaining 513.4 million tons. The available 513.4 million tons of crop straw can be used as feed and industrial raw materials, and most of the rest can also be used as cooking and heating fuel for farmers. The consumption of straw as energy in rural areas nationwide is about 286.2 million tons, but most of them are in inefficient use, that is, directly burning on the wood stove conversion efficiency Only about 10% - 20%. With the development of rural economy and the increase of farmers' income, regional differences are gradually expanding, and the proportion of commercial energy in rural domestic energy consumption is increasing at a rapid speed. In fact, the increase of farmers' income and the difficulty of obtaining commercial energy can be the opportunity and motivation for them to turn to commercial energy. In rural areas close to commodity energy production areas or rich rural areas, commodity energy (such as coal Liquefied petroleum gas ) has become its main energy consumption for cooking. The straw used in the traditional way has become the first object to be replaced, resulting in an increase in the amount of straw discarded in the field and directly burned year by year. In many areas, the amount of waste straw has accounted for more than 60% of the total amount of straw, which not only harms the environment, but also wastes resources. Therefore, it is imperative to speed up the high-quality conversion and utilization of straw.

animal manure

Livestock manure is also an important biomass energy. In addition to a small amount of direct combustion in pastoral areas, livestock manure is mainly used as raw material for biogas fermentation. The main livestock in China are chickens, pigs and cattle. According to the variety, weight, fecal excretion and other factors of these livestock, fecal resources can be estimated. According to calculation, the total amount of livestock manure resources in China is about 850 million tons, equivalent to 78.4 million tons of standard coal, including 578 million tons of cow manure and 48.9 million tons of standard coal, Pig manure 259 million tons, 22.3 million tons of standard coal, 14 million tons of chicken manure, and 7.17 million tons of standard coal.

Among the excrement resources, the excrement of large and medium-sized farms is more convenient for centralized development and large-scale utilization. There are more than 6000 large and medium-sized cattle, pig and chicken farms in China, which discharge more than 800000 tons of feces and urine and flushing sewage every day. The annual fecal sewage resource in China is 160 million tons, equivalent to 11.575 million tons of standard coal.

domestic garbage

With the expansion of urban scale and the acceleration of urbanization process, the production and accumulation of urban garbage in China are increasing year by year. In 1991 and 1995, the whole country Output of industrial solid waste 588 million tons and 645 million tons, respectively. During the same period, the amount of urban domestic waste increased at an annual rate of about 10%. In 1995, the total number of cities in China reached 640, and the amount of garbage cleared and transported was 107.5 million tons.

Urban domestic waste is mainly a mixture of household waste, commercial and service waste and a small amount of construction waste. Its composition is relatively complex, and its composition is mainly affected by the living standard of residents, energy structure, urban construction, green area and seasonal changes. The garbage composition of China's major cities has shown a trend of transition to modern cities, with the following characteristics: First, the organic content of garbage is close to 1/3 or even higher; Second, food waste is the main component of organic matter; Third, the content of easily degradable organic matter is high. The calorific value of urban garbage in China is 4.18 Megajoule /G (1000 kcal/kg).

Benefit analysis

Announce

edit

Simple analysis on the benefit of biomass power generation energy forest

The growing area of the Swedish willow clonal energy forest is mainly related to the promotion of willow as a crop by the Swedish Farmers' Trade Association and other institutions. At the same time, the government subsidy system also provides a large area of promotion of willow energy forest necessary condition 。 There are about 11000 hm willow energy forests in southern and central Sweden, of which 2000 hm were planted in 1994 and 5000 hm were planned to be planted in 1995. The average biomass production of these energy forests per hectare per year is 10-12t, which is equivalent to 25-30m wood or 4-5m fuel oil, about 25-30 barrels of crude oil. If the biomass produced is used for power generation, these energy forests can generate 7300-8760kwh of electricity per hectare per year, calculated according to the power generation efficiency of domestic direct fired generating units at 1.37kg/kwh; If it is calculated according to 1.05kg/kwh of raw material consumption per unit electricity of imported direct fired generating units, 9500-11430kwh can be generated per hectare per year. If the bamboo willow is taken as the analysis object, the average biomass production per hectare per year can reach more than 37.8t under the condition of ultra short-term rotation (rotation period is 1-2 years), which is equivalent to 94.5m wood or 15.12m fuel oil, about 94 barrels of crude oil. Affected by the global financial storm, the international crude oil price has plummeted. Based on the current average price of 43 dollars/barrel, the annual output value per hectare is 4042 dollars, equivalent to about 27500 yuan (exchange rate 6.8). These energy forests can provide 27560kwh of power generation per hectare every year; Each hectare can generate 36000kwh of electricity every year.

significance

Announce

edit

China is a country with a large population and a rapidly developing economy. In the 21st century, China will face the dual pressure of economic growth and environmental protection. Therefore, changing the mode of energy production and consumption and developing and utilizing renewable clean energy resources such as biomass energy are of great significance for establishing a sustainable energy system, promoting national economic development and environmental protection.

The development and utilization of biomass energy is of special significance to China's rural areas. 80% of China's population lives in rural areas, and biomass energy such as straw and firewood is the main living fuel in rural areas. Although the use of commodity energy such as coal has increased rapidly in rural areas, biomass energy still occupies an important position. In 1998, the total domestic energy consumption in rural areas was 365 million tons of standard coal, including 207 million tons of standard coal for straw and firewood, accounting for 56.7%. Therefore, developing biomass energy technology to provide energy for living and production in rural areas is an important task to help these areas shake off poverty and become rich and achieve the goal of a well-off society.

From 1991 to 1998, the total rural energy consumption increased from 568 million tons of standard coal to 672 million tons of standard coal, an increase of 18.3%, with an average annual growth of 2.4%. In the same period, the number of rural households using liquefied petroleum gas and electric cookers increased from 15.78 million to 49.37 million, more than twice, with an annual growth rate of 17.7%, more than six times the total growth rate. It can be seen that with the development of rural economy and the improvement of farmers' living standards, the demand for high-quality fuel in rural areas is increasingly urgent. Traditional energy The utilization mode has been difficult to meet the needs of rural modernization, and the high-quality conversion and utilization of biomass energy is imperative.

Biomass energy high-tech conversion technology can not only greatly accelerate the process of energy modernization for rural residents and meet the urgent needs of farmers for high-quality energy after they become rich, but also can be applied in production fields such as township enterprises. Due to China's vast land and large population, conventional energy cannot fully meet the growing demand of the vast rural areas, and because various international conventions on environmental issues are being formulated to limit carbon dioxide, etc Greenhouse gas emissions This is very unfavorable for China, which is dominated by coal. Therefore, based on the existing rural Biomass resources Research on new transformation technology and development of new equipment are both urgent needs for rural development, as well as for reducing emissions, protecting the environment and implementing sustainable development strategies.

Domestic status

Announce

edit

China is rich in biomass energy resources. It is estimated that China's theoretical biomass energy resources are about 5 billion tons of standard coal, which is about four times of China's total energy consumption. Under collectable conditions, the available biomass energy resources in China are mainly traditional biomass, including crop straw, firewood, livestock manure, domestic garbage, industrial organic waste residue and wastewater.

51% of agricultural output is converted into straw, with an annual output of about 600 million tons, about 300 million tons can be used as fuel, equivalent to 150 million tons of standard coal; The annual available amount of forestry waste is about 900 million tons, about 300 million tons can be used for energy, equivalent to 200 million tons of standard coal. The planting area of energy crops such as sweet sorghum, jatropha curcas, pistachio chinensis and tung oil trees can reach more than 20 million hectares, which can meet the annual output of about 50 million tons Bioliquid fuel Raw material demand. Theoretically, livestock breeding and industrial organic wastewater can produce about 80 billion cubic meters of biogas annually.

Diversified development of energy

Biofuels not only help promote energy diversification, but also help us get rid of the traditional Fossil energy It can also reduce greenhouse gas emissions and alleviate the pressure on the environment. Therefore, it is regarded as one of the alternative fuels and has a positive significance for strengthening energy security.

Accelerate the development of biomass energy industry

The National Energy Administration will organize key enterprises and key resource provinces to increase innovation and promote the development of advanced biomass energy industry.^[4]

The Special Plan for Advanced Biomass Energy Chemical Industry Demonstration Project will be prepared and issued as soon as possible to clarify the development goals, main tasks and access conditions of biomass energy chemical industry. Relying on key resource areas and powerful backbone enterprises Cellulosic ethanol Industrialization demonstration and bioenergy key innovation fields such as alcohol, electricity, gas and chemical cogeneration should be selected and implemented well. The National Energy Administration will work with relevant departments to introduce relevant supporting policies in combination with the development priorities and directions of bioenergy.^[4]

Expert advice

On September 2, 2022, at the "First Chinese Ecological and Environmental Protection Industry Service Double Carbon Strategy Academician Forum", Jia Zhibang suggested that indirect emission reduction such as biomass energy should be included in the carbon emission reduction trading market system.^[8]

Mass energy research

Announce

edit

Biomass energy utilization diagram^[5]

Biomass energy research and development has become one of the major hot topics in the world, and has attracted the attention of governments and scientists all over the world. Many countries have formulated corresponding development and research plans, such as Japan's Sunshine Plan, India's green energy project, the United States' energy farm and Brazil's alcohol energy plan, among which the development and utilization of biomass energy accounts for a considerable proportion. Most of the biomass energy technologies and devices abroad have reached the level of commercial application, realizing large-scale industrial operation. Take the United States, Sweden and Austria as examples. The conversion of biomass into high-grade energy has achieved considerable scale, accounting for 4%, t6% and 10% of the country's primary energy consumption, respectively. In the United States, the total installed capacity of biomass power generation has exceeded 10 gigawatts, and the single unit capacity has reached 10-25 megawatts; The Staten Garbage Treatment Station in New York, the United States, invested 20 million dollars to treat garbage by wet method and recycle biogas for power generation and fertilizer production. Brazil is the country with the most distinctive development and application of ethanol fuel, and has implemented the largest ethanol development plan in the world. Ethanol fuel has accounted for more than 50% of the country's automobile fuel consumption. The United States has developed the technology of using cellulose waste to produce alcohol, and has established a 1 MW rice husk power generation demonstration project with an annual output of 2500 tons of alcohol. In 2013, the global biomass power generation capacity was 413778.1 million kilowatt hours, and the annual revenue of the global biomass power generation market was $28681.8 billion.^[6]

problem analysis

Announce

edit

The incentive of high energy prices and consideration of energy security make the governments of all countries attach great importance to biomass energy. Countries have different emphasis on the development of biomass energy, but the two main reasons are the same, namely energy substitution and environmental protection.

According to the 2007 World Renewable Energy Report, the global production of bioethanol increased from 33 billion liters in 2005 to 39 billion liters in 2006; Among them, the output of the United States was 18.3 billion liters, an increase of 22%, surpassing that of Brazil. Fuel ethanol consumption in Brazil increased from 15 billion liters in 2005 to 17.5 billion liters in 2006. Fuel ethanol supplies 41% of non diesel motor vehicle fuel, and about 70% of Brazilian motor vehicles use "mixed fuel". The production of fuel ethanol in the EU has grown rapidly, with an increase of 77.8% in 2006, but the absolute number is still less than that in Brazil and the United States.

Realistic in China Socio economic environment There are also some negative factors restricting the development and application of biomass energy:

The market environment and security mechanism are not perfect

The development of biofuel ethanol in China lacks a clear development goal, has not formed a continuous and stable market demand, and is still in the stage of "production based sales, planned supply". All links from production to sales of domestic biofuel ethanol have been strictly controlled by the government departments, which is a closed operation of policy, and has not yet formed a real sense of marketization.

Incomplete system

In the afternoon of 2001, China issued two mandatory national standards, namely, denatured biofuel ethanol (GB 183502-2001) and ethanol gasoline for vehicles (GB183512-2001), It is extremely urgent to formulate relevant basic standards and process control standards for biofuel ethanol from different biomass sources on the basis of existing standards.

Difficult to commercialize

Decentralized resources, backward collection means and slow industrialization process restrict the large-scale and commercial utilization of high and new technologies of biomass energy. Centralized power generation and heat supply is the main technical way of efficient and clean utilization of biomass energy internationally. However, these technologies need to have a certain scale to produce economic benefits.

Backward technology

The technical content of the equipment used is low, the investment in R&D is too small, and the R&D of some key technologies has not progressed much. For example, the gas production rate of anaerobic digestion is low, and the automation degree of equipment and management is poor; The tar problem in gasification utilization has not been solved, affecting long-term application; The efficiency of biogas power generation and gasification power generation is low, and the problem of secondary pollution has not been completely solved.

Lack of relevant policies

There is a lack of policies specifically supporting the development of biomass energy and encouraging the production and consumption of biomass energy. In the absence of certain economic subsidies, it is difficult to achieve large-scale biomass cogeneration, and the competitiveness is weak.

Land contradiction

Biomass energy is not coordinated with agriculture and forestry in the use of resources. Energy crops have begun to become the main body of biomass energy in many countries. However, China is short of land resources, and there is a contradiction between energy crops and agriculture and forestry competing for land.

Utilization constraints

Some problems restricting biomass power generation are gradually emerging. The low subsidy standard of electricity price makes the biomass power generation project face loss once it is put into operation. The Renewable Energy Law clearly points out that preferential tax and loan policies should be formulated to stimulate the development of renewable energy. However, relevant tax rebate policies on biomass power generation have not yet been implemented.

Development prospect

Announce

edit

The future development of China's biomass energy industry will focus on biogas and biogas power generation, liquid fuel, biomass solid briquette fuel and biomass power generation; The policy environment for promoting the development of biomass energy industry will be further improved; The technical level was further improved; More large enterprises will participate; The biomass energy industry will certainly become a new growth point of China's national economy.^[7]

(1) A good macro policy environment has gradually formed, providing good development opportunities for the biomass energy industry

(2) The technical level has been continuously improved and the product field has been further expanded

(3) Large enterprises actively participate in promoting the industry to enter a stage of rapid development^[7]

Novice on the road

Growth task Getting Started with Editing Edit Rule Edit by myself

I have questions

Content query Online Service Official post bar Feedback

Complaints and suggestions

Report bad information Failed to appeal through entries Complaint of infringement information Blocking query and unblocking

Jinggong Network Anbei No. 1100000200001