In some urban-rural fringe areas, where piles of garbage are piled high, groups of ragged men, women and children, regardless of the lingering stench and the bites of mosquitoes and flies, are busy tumbling, digging and picking up. Picking, some people have made a fortune from picking up trash. There is no doubt that there are resources in garbage. So, how much of the discarded materials in our daily life can be used? Please look at the following figures:
Toothbrush: The middle school student toothbrush produced by Beijing Stomatological Hospital weighs 9.1 grams. If you replace one every three months, press Assuming that Beijing has a population of 12 million, the weight of toothbrushes thrown away throughout the year is 436.8 tons. This does not include disposable toothbrushes discarded by hotels;
Toothpaste: "Colgate" full-effect fluoride toothpaste with a net content of 120 grams, the carton weighs 14.9 grams, and the toothpaste tare weight is 16 grams , if each household uses 1 tube per month, 3 million households will discard 1112.4 tons of waste paper and toothpaste skins a year; 3. Soap: The net content of "Safeguard" soap is 125 grams, and its carton weighs 7.4 grams. If 3 million households each With a monthly consumption of 1 yuan, 266.4 tons of cartons are discarded in a year;
Dairy products: Beijing Sanyuan VAD fresh milk has a net content of 243 ml in a packaging bag weighing 3.1 grams. If 2 million people use one bag per day According to statistics, the total weight of plastic bags thrown away in a year is 2,263 tons;
Hypertension medicine: 10-piece carton and empty medicine board of "Beijing Step-down No. 0" produced by Beijing "Shuanghe" The weight of the product and instructions is 11.3 grams, and discarded items account for 89% of the total weight. According to statistics, elderly patients in Beijing account for more than 40% of the patients with this disease. About 560,000 people need to take medication for life. Taking one tablet a day will cause 203.6 tons of "No. 0" packaging to be thrown away in a year. The world produces 490 million tons of garbage every year, and China alone can produce 1.5 kilograms of garbage per person per day. The cumulative stock of domestic waste in China's cities has reached 7 billion tons. According to the forecast of the State Environmental Protection Administration, China's annual urban waste output will be 152 million tons in 2010 and will reach 210 million tons in 2015 and 2020.
China's urban waste incineration power generation was first put into operation in 1987. After that, with the launch of a large number of environmental protection industrialization and environmental protection high-tech industrialization projects, waste incineration power generation technology has developed rapidly, realizing the localization of large-scale waste incineration power generation technology, and the waste incineration processing capacity has increased in the past five years. increased by 5 times.
The principles of garbage disposal are harmlessness, reduction and resource utilization. Waste incineration power generation can save a lot of land resources by greatly reducing landfills. It also reduces the air pollution of groundwater and the surrounding environment of the landfill.
According to China's current policies, urban domestic waste incineration power generation technology will be dominated by mechanical grate furnaces, supplemented by coal-waste mixed combustion fluidized bed waste incineration technology and other technologies. Based on the calculation of a two-stage reciprocating waste incineration equipment with a daily processing capacity of 1,800 tons, the annual power generation can reach 160 million kilowatt hours, which can save 48,000 tons of standard coal, and reduce annual nitrogen oxide emissions by 480 tons and sulfur dioxide emissions by 768 tons.
“Coalbed methane, domestic waste landfill gas, nitrogen oxides, etc. are important sources of global warming.” Han Yeju, President of China and Asia Pacific of the British Syndic Carbon Fund, believes that waste power generation is mainly affected by some The constraints of technical or process issues, such as the highly toxic waste gas generated by combustion during power generation, have not been effectively solved for a long time, so the key to effective emission reduction is the use of advanced technology.
In developed countries, waste treatment and resource utilization have become mature industries, and waste incineration power generation technology is developing towards large-scale and high-efficiency. For example, European countries have formulated strict waste incineration standards and strictly implemented them; the United Kingdom has stipulated in its non-fossil fuel convention and Germany in its new energy law that the power generated by direct waste incineration is mandatory to be connected to the Internet, and electricity price subsidies or green electricity prices are implemented. .
It is understood that China's annual urban domestic waste production is about 150 million tons, of which landfill accounts for 70%, incineration and composting account for 10%, and the remaining 20% ??is difficult to recycle. Among them, the waste-to-energy rate is less than 10%, which is equivalent to wasting 2,800 megawatts of electricity every year. The value of discarded "renewable waste" is as high as 25 billion yuan.
According to the "National Urban Environmental Sanitation "Eleventh Five-Year Plan"", the national urban domestic waste removal volume will reach 180 million tons in 2010, and harmless waste treatment will reach more than 60%. Experts pointed out that if by 2010, the amount of waste incineration accounts for 10% of the total waste production, and the incineration heat is used for power generation and heating, then by 2010, new waste incineration equipment with a daily processing capacity of 32,000 tons will be needed.
With the continuous development of technologies in various aspects such as garbage recycling, processing, transportation, and comprehensive utilization, waste-to-energy generation is likely to become one of the most economical power generation technologies. From the perspective of long-term benefits and comprehensive indicators, it will be optimal. for traditional electricity production.