With the development of the world economy, the demand for energy in countries around the world is getting stronger and stronger. Traditional energy, represented by coal, oil and natural gas, is being chased by countries all over the world;
0 Preface
With the development of the world economy, the demand for energy in countries around the world is getting stronger and stronger. Traditional energy, represented by coal, oil and natural gas, is being chased by countries all over the world. In China, in order to cope with the increasingly serious shortage of electricity, power plants have been built in large numbers across the country, and the prices of coal and oil have also risen sharply. The country’s energy needs and energy security issues have become more and more urgent in front of us.
Since the oil crisis of the 1970s, many Western countries, represented by Denmark, have begun research on various biomass energy generations. Domestic waste, animal waste, and plant dead branches have all been used to try to generate electricity. However, after more than 30 years of scientific research and power plant practice, it is proved that only crop straw power generation is the most suitable choice. First, the pollution of straw burning is less, the sulfur content is only 3.8%0, which is much less than the sulfur content of coal 1%. Secondly, the carbon content of straw is higher, the heat energy generated is larger, and the calorific value per straw is 2t. It is equivalent to the calorific value of It coal and is also suitable for power generation.
1. Analysis of the prospect of straw power generation in China
The annual production of crops in China alone reaches 700 million tons, and it is expected to increase to 800 million tons by 2010. At present, about 145 million tons of straw is used for livestock feed, 0.991 billion tons for returning fertilizer, 0.14 billion tons for industrial raw materials, 280 million tons for farmers' traditional living fuel, and the rest are almost completely discarded and burned. ,What a pity. China's straw production is abundant. The annual amount of straw discarded is about 100 million tons, equivalent to 50 million tons of standard coal. Between 2000 and 2010, the amount of straw obtained per year is about 3.5-370 million tons, which is equivalent to about 170 million tons of standard coal; if these straw resources are used for power generation, the average annual operation of a 90 GW thermal power unit is 5,000 h, and the annual average power generation is 450 billion kWh. It is estimated that by 2020, the annual amount of straw discarded in the country will reach more than 200 million tons, which is equivalent to 100 million tons of standard coal, equivalent to the annual output of Henan, a major coal-producing province.
Crop straw is also a very good resource. If it can be recovered by straw pulverizer and then passed through straw briquetting machine, granule machine and feed pellet machine to make biomass fuel feed for burning and livestock consumption is not the best of both worlds. The method, and if you get the outside sales, you can increase your income.
In most rural areas of China, straw is burned in the field every year during the wheat harvest period, causing heavy smoke and air pollution around the farmland. At the same time, it also caused traffic accidents in nearby roads due to low visibility, and the airport also experienced flight delays due to heavy fog or the aircraft could not take off and land. Straw burning not only pollutes the environment, but also seriously affects the living and production activities of local residents. If we make rational use of straw resources, it will be of great benefit to reduce pollution and waste, increase farmers' income, build new countryside, and create a harmonious society. For example, using straw to generate electricity, the straw ash after power generation can also be reused. It is rich in chemical components such as potassium, magnesium, phosphorus and calcium, and can be used as a high-efficiency agricultural fertilizer.
However, as a new type of energy utilization, there are many different applications of straw power generation in China.
1.1 Straw power plant fuel source is unstable
Straw itself has many uses, and farmers can have multiple choices, so the fuel source of straw power plants may not be stable.
(1) Straw can be processed into fuel ethanol. In the fuel ethanol production plant of Fengxian in Shanghai, the purchase price of straw is 200~250 yuan/t. Except for the profit and freight of the middlemen, the straw can be obtained by the farmers. It is 80-100 yuan / t.
(2) Straw can produce “straw gasâ€. In Mazhuang Village, Qingshanquan Town, Xuzhou, local farmers use straw gas for cooking, which costs 40% more than burning coal and 60% less than burning gas; and the local gas station acquires from the villagers. Straw, the purchase price is about 160 yuan / t.
(3) China's national conditions are that there are fewer people in rural areas, and natural villages are scattered. Most of the rural areas are not cultivated on a large scale. In most areas, there is not much farmland per household, less crops are harvested, and the actual income of individual farmers from selling straw is less. Straw power plants generally require tens of thousands of tons of straw per year, especially for large-scale straw power plants, which reach several hundred thousand tons per year. If the power plant establishes a special acquisition agency to expand the collection radius, it will involve many problems such as straw transportation, sorting, storage, anti-corrosion, etc., and the cost of straw purchase will rise sharply. If the purchase price of straw is reduced, and the other uses of straw and their corresponding purchase prices are compared, the purchase price of the power plant straw does not have any competitive advantage.
(4) China's straw resources are concentrated in several major grain producing areas (such as North China, Northeast China, East China and South China), and the total straw output in Shandong, Hebei, Henan and other places exceeds 60 million tons, suitable for straw power generation. The focus is on the area, while the straw production in other areas is relatively small. The development of straw power generation should be carefully considered. The energy utilization of straw is also closely related to the degree of economic development in various places. Farmers with higher per capita income would rather spend more money on clean and easy-to-clean energy sources, while those with lower per capita incomes would be more likely to use crop straw that is not readily available for use as a daily energy resource. For example, in terms of straw fuel, the proportions of Sichuan, Shandong, and Zhejiang provinces were 41.2%, 34%, and 23.3%, respectively, while in the abandonment rate of straw, Sichuan Province was 10%, and Zhejiang Province was 53%. This is also consistent with the degree of economic development in these areas.
1.2 China's straw power plant scale should not be too large
At the present stage in China, from the perspective of the construction scale of straw power plants, it is not advisable to build large-scale straw power plants too much, which is also determined by China's national conditions.
First of all, large-scale straw power generation systems in foreign countries generally use more mature technologies from developed countries in the West, and most of them use a single biomass fuel. Without the good applicability or engineering practice of mixed biomass, this kind of power generation equipment At home, these systems often have problems once there is a problem with the fuel supply or the need to replace biomass. In addition, in order to improve efficiency, foreign large-scale power generation systems often have large designed capacity, usually above 20 MW, which means that the annual straw consumption is usually around 300,000 tons, and the investment of power plants will be 200-300 million yuan. The on-grid price is higher, and it is harder to fall in the short term. Big investments mean big risks, and average investors are more cautious about this new energy system. The small straw power plant just avoids all the above problems. The equipment needed for the power plant below 3 MW can be fully localized, the price usually does not exceed 15 million yuan; the annual straw demand is about 20,000 tons, around the power plant. The yield of crop straw in several natural villages can meet the demand, and it can guarantee the supply of stable and cheap straw.
1.3 Straw power generation cost is high
Under current circumstances, the cost of straw power generation does not have the ability to compete with conventional energy products. The cost of thermal power in China is between 0.1~0.2 yuan/(kWh), while the cost of straw power generation is between 0.2~0.3 yuan/(kWh). The cost of straw power generation is about twice that of thermal power generation. Competing with conventional energy feed-in tariffs. Under this circumstance, the Renewable Energy Law, which was officially implemented on January 1, 2006, has policy support for the on-grid price of renewable energy power generation. Under the guidance of the “Recommended Measures for the Management of Price and Cost Sharing of Renewable Energy Power Generation†(hereinafter referred to as the “Measuresâ€), China has adopted two forms of government pricing and government guidance prices for renewable energy pricing. Among them, the biomass power generation on-grid price is subject to the government-guided price. The electricity price standard consists of the on-grid electricity price of the desulfurization direct-fired units in 2005 (autonomous regions and municipalities directly under the central government) plus the subsidized electricity price of 0.25 yuan/(kW·h). At the same time, however, the Measures also impose restrictions on the subsidy price of biomass power generation, which stipulates that the on-grid price of biomass power generation will be cancelled after the project has been in operation for 15 years. Moreover, since 2020, the newly approved and approved power generation project subsidy price has been reduced by 2% compared with the previous year's approved project. This regulation shows that straw power generation enjoys national preferential policies for a maximum of 15 years. From the current situation, high-cost straw power generation is not an opponent of conventional energy generation in the fair market competition. From a positive point of view, the fuel cost of thermal power plants as non-renewable energy sources will continue to rise, while the cost of straw power generation is declining. At the same time, the continuous updating of technology has made it possible for China to have its own core technology. After 15 years, the price of straw power generation It is possible to reach the grid standard price. However, the industry has different views. Many people think that if the straw power generation loses the support of the state, it will be difficult to survive. In Denmark, in addition to exempting energy taxes and carbon dioxide taxes, the straw power generation company also gives priority to calling electricity and heat generated by straw. The government also puts forward requirements for power generation operators. Each power generation operation enterprise must have a certain amount of renewable energy capacity, and the subsidies for the above-mentioned taxes and energy-saving technologies will continue to increase in the future. Compared with foreign government subsidy policies, China's renewable energy policy is not detailed enough and comprehensive, and needs to be gradually revised and improved.
2. The utilization of straw resources should conform to China's national conditions.
Ni Weidou, an academician of the Chinese Academy of Engineering, profoundly put forward at the 2006 Tsinghua University Doctoral Forum, “Energy Development under the National Energy Strategyâ€: China should have strategic thinking in the use of biomass energy and traditional energy coal represented by straw. In China, coal-fired industrial boilers are the main source of industrial pollution in China, and are in the same order of magnitude as coal-fired power plant boilers. Every year, China's industrial boilers consume about 400-500 million tons of coal, and the utilization efficiency is only 25% to 30%, which is a great waste. How to reduce the high pollution and low efficiency consumption of this part of coal is an extremely important entry point, and the average energy saving effect occupies a large share of the entire energy structure.
Biomass energy represented by straw is very suitable for industrial boilers with small capacity and low parameters. Ni Weidou proposed two kinds of resource allocation schemes: the first one is to use 100 million tons of standard coal for the current high-pollution and low-efficiency industrial boilers, and 160 million tons of biomass for power generation; the second is 160 million tons. Biomass is used in industrial boilers to replace 100 million tons of standard coal, and the replaced 100 million tons of standard coal is used in modern high-efficiency large-scale power station boilers with 90% desulfurization rate. The effect of the configuration of the two different schemes is quite different, mainly because the second scheme is used to disperse the demand and the concentrated energy is used to exert its strengths. Therefore, Academician Ni Weidou pointed out that the biomass energy represented by straw in China can be used to inefficiently and highly pollute the medium-sized boilers in towns and small and medium-sized boilers in rural areas (the boiler efficiency is only about 60%, which cannot be desulfurized and denitrified). Coal is replaced and used in high-efficiency, low-pollution large-scale power station boilers. This is a win-win situation for rural life, environment and the use of various energy sources. It is also an effective method for China's national conditions.
For an energy resource, it should be examined from a strategic perspective on its rational position in the country's entire energy system. It cannot be discussed on a case-by-case basis. This issue must be considered from a large perspective of the entire energy system across the country. For an energy resource, it is not the first question of what it can do, but the question of what it should do and what it is suitable for. China's biomass energy is generated in the vast rural areas and should be used in combination with the characteristics of rural China and the differences between developed countries.
3, the conclusion
Straw power generation is a promising new energy utilization method, which is worthy of vigorous research, application and promotion. Under the current national conditions in China, the problem of straw collection and transportation should be solved; the economic impact of straw purchase price on farmers should be studied; the investment income risk of large and small straw power plants should be demonstrated; while the practice of straw power generation should be accumulated, Continuously improve and supplement the government's subsidy policy for renewable energy; do a strategic plan for the corresponding status of biomass energy such as straw power generation in the national energy system, so that China's energy utilization can be harmonious, orderly and healthy in the 21st century. Continue to develop.
Sanmenxia Futong New Energy produces and sells biomass fuel feed machinery such as pellet machine, straw briquetting machine and feed pellet machine. target=_blank>Mechanical equipment can perfectly solve the problem of crop straw treatment.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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