The development of municipal waste energy, the use of municipal waste power generation, harm into profit, waste into treasure, not only reduces the garbage pollution of the environment, but also for the solution of today's energy scarcity problem opened up a new way to solve the increasing urban environmental pollution and the growing shortage of conventional energy is a best choice. Experts predict that waste-to-energy generation will become a new protagonist in the energy market in the 21st century.
Rubbish is the waste material abandoned by human beings in production and life. With the development of the world's economy and the rapid growth of the population, industrial and domestic waste is increasing. At present, the total amount of garbage produced globally reaches 45 billion tons per year, about 8 tons per capita. Among them, more than 10 billion tons of new garbage are produced globally every year, with an incremental rate as high as 8 to 10 percent. Such a rich garbage resource has become another new field of development of the global scientific and technological community.
With the enhancement of people's awareness of environmental protection, the rise of the green movement and the global energy shortage to human beings to light up the "yellow card" warning, the scientific treatment of municipal garbage and the rational use of the scientific and technological community has become a high priority of the research topic. Scientists around the world in the search for ways to deal with urban waste and the development and utilization of a variety of new energy sources, found that the abandoned city garbage is also a very valuable new energy.
Scientific research shows that in the city garbage, contains a large number of secondary energy materials - organic combustibles, which contains the proportion of combustibles and heating value is quite high. Such as ash in the usual municipal garbage, combustible materials accounted for 27%; vegetable combustibles accounted for 23.5%; paper combustibles accounted for 84.4%; plastic combustibles accounted for 88%. Combined, about 2 tons of garbage burning heat is equivalent to 1 ton of coal combustion issued by the heat. Therefore, energy experts believe that a city's garbage, like a low-grade "open pit mine", can be developed indefinitely. And the development and use of the most cost-effective method, is to develop urban waste power generation.
The use of municipal waste energy as a new energy industry, in recent years, rapid development in the global boom. At present, the United States, Japan, France, Britain, Germany, the Netherlands, Italy and other industrially developed countries will be included in the national waste power generation "agenda", invested a lot of money and manpower, the use of modern high-tech means, large-scale development of new technologies to generate electricity from municipal waste, and tend to make it commercialized. At present, the world has more than 800 all kinds of garbage power station in operation. Germany in 1995 there were 67 waste power plants; the United States has more than 170 waste power plants; Japan currently has 125 waste power plants, total power generation capacity of 450 megawatts, by 2010 waste power plants will reach more than 200, the total power generation capacity of 10 gigawatts (10 × 109 watts); the United Kingdom will be more than 50% of the garbage used for power generation. Therefore, municipal waste power generation as a new energy source, its development prospects are broad.
Currently the use of municipal waste power generation, there are a variety of ways. One is the use of municipal waste landfill biogas, power generation, and more importantly, waste incinerator combustion waste heat for power generation, and then the garbage is made of solid fuels directly burned for power generation.
The treatment of urban garbage, in the past, is mostly transported to the suburbs for sealed landfills. With the development of modern bio-engineering high technology, now the use of microbial engineering new technology, with anaerobic bacteria for fermentation treatment, through biodegradation, you can produce biogas. Each ton of domestic waste can produce 400 cubic meters of biogas. The biogas is then used to generate electricity, which is fed into the power grid for use. Thus the garbage "biogas field" came into being, and "biogas field" power generation prospects.
The use of garbage "biogas field" power generation, can be said to be the current technology is mature, low investment, low cost, easy to use and manage, and is highly favored by the developed countries of a way of urban waste treatment. The Netherlands in 1991 has enacted the municipal waste biogas power generation program, and invested more than 80 million U.S. dollars, the construction of several large-scale biogas power plants. Widest garbage biogas field in the north of the Netherlands, 15 million tons of domestic garbage storage, every hour can produce 5000 cubic meters of biogas, can be converted into 4.5 megawatts of electricity. France held a "European Conference on Fermented Waste Development" in Metz, put forward to accelerate the use of garbage production of biogas power generation program. Finland's first garbage biogas field power plant in Vantaa completed and put into operation, has landfilled 1.03 million tons of garbage, in the next 10 years can produce 30 million cubic meters of biogas for power generation. Britain's current garbage biogas field power generation capacity of 18 megawatts. The UK Department of Energy intends to invest another 150 million pounds in 10 years to build a number of garbage biogas field power plants. The U.S. Illinois garbage biogas field power plant, covers an area of 61 hectares, landfill 1.8 million tons of garbage, power generation capacity of 1,600 kilowatts, equivalent to 28,000 barrels of oil each year with the power generation capacity. Japan in Dry Leaf County built 42,000 square meters of garbage biogas field power plant, the annual power generation capacity of 11,000 kilowatt hours.
Establishment of waste incineration plant, the garbage will be incinerated, has long been used in various industrially developed countries, and in the incineration process, the recovery of its thermal energy, and used to generate electricity, to achieve the waste incineration of energy, or in recent years.
This is due to the city landfill disposal of waste, covers a large area, there is pollution. And the use of waste incineration treatment, not only after incineration, the remaining volume and weight of the garbage is reduced, covers an area of small. At the same time incineration removes harmful substances, and through the flue gas purification system after treatment, can prevent air pollution. With the development of new modern thermal energy technology, the heat generated by the garbage in the incineration process can be processed by the recovery system to push the turbine generator to generate electricity and be incorporated into the power grid for use. Therefore, the use of incineration method of waste disposal for power generation, is currently an important development trend in developed countries around the world.
In addition, many countries are also actively carrying out the garbage made of solid fuel, or with industrial waste directly burned, for power generation. India in the city of Madras to build a garbage concentrated fuel power plant, its daily treatment of 60 tons of garbage fuel, power generation capacity of 5 megawatts. The United Kingdom in Scotland built an annual incineration of 8 million used tires waste thermal power plant, to 25,000 households to supply electricity. Japan in Fukushima Prefecture, Iwaki established a waste plastic as fuel for the thermal power plant, the daily treatment of waste plastic 200 tons, generating capacity of 25 megawatts, to 10,000 households to supply electricity.
China's garbage "resources" are also very rich, the country produces more than 100 million tons of garbage each year, the annual growth rate of 10%. China's waste-to-energy industry has begun, the use of municipal waste to generate electricity has been included in the agenda of major cities. Many large and medium-sized cities have been carried out waste power generation.
Shenzhen City, 10 years ago, has taken the lead in the country to carry out waste-to-energy, there are two saturated steam waste incineration boiler, 400 tons of garbage incineration, power generation capacity of 3 megawatts; Hangzhou City, the introduction of foreign equipment, will be built, "garbage methane gas field" power plant; Zhuhai, China will be used in the design of the garbage incinerator, daily The city of Hangzhou has introduced foreign equipment to build a "garbage biogas field" power plant.
Knowledge Points
Biodegradation
Biodegradation refers to the phenomenon of microorganisms converting organic substances into simple inorganic substances. The excretions and dead bodies of various organisms in nature are converted into simple inorganic matter by the decomposition of microorganisms. Microorganisms also degrade synthetic organic compounds. For example, through oxidation, the ai agent into dieldrin; through the reduction, the nitro-containing pesticide reduced to amine; aromatic ring cleavage phenomenon is also a common microbial degradation of a reaction.
Microbial degradation makes it possible for the cycle of life elements to be repeated, so that a variety of complex organic compounds can be degraded, thus maintaining a virtuous cycle of the ecosystem.