Led by Guangzhou Energy Research Institute of Chinese Academy of Sciences and implemented by chief scientist Chen Yong, Chengdu Institute of Biology of Chinese Academy of Sciences completed the "Integrated Technology Demonstration of Municipal Domestic Waste Recycling and Energy Utilization", which is one of the 100 scientific and technological innovation projects in Guangdong Province. The demonstration project was built in Boluo County, Guangdong Province, with 100 projects specially supported as the starting capital, with a total investment of 22.85 million yuan. This is a 200-ton/day energy self-sufficient municipal solid waste comprehensive treatment and utilization system. The first phase of the project deals with 54,000 tons of domestic garbage every year, and produces 65,438 tons of organic compound fertilizer+8,000 tons.
The problem of urban garbage disposal affects the national economy and people's livelihood.
The rapid growth of garbage production has seriously harmed the environment. The annual storage of garbage in China is 6 billion tons, 1.997, and the annual output of garbage in China is1.40 billion tons, with an annual growth rate of 8- 10%. Up to now, the vast majority of municipal solid waste in China is still mainly piled and buried in the open air, which not only occupies valuable land resources, but also causes serious secondary pollution to the environment.
It is imperative to study the comprehensive management technology. On the one hand, the main obstacle to the recycling of garbage lies in the complex composition of garbage itself and the difficulty of recycling. On the other hand, the research and development of related technologies has not kept up. The existing utilization technology often adopts a single mode (such as incineration for power generation) to treat different garbage components in the same way, which leads to large consumption and poor economy in the treatment process itself. Therefore, it is of great significance to study the key technologies of comprehensive treatment according to the different components of garbage according to local conditions, which is a major event related to the national economy and people's livelihood.
The demonstration project has been carefully conceived and adopted comprehensive technology to foster strengths and avoid weaknesses.
Domestic and foreign municipal solid waste treatment mainly adopts landfill, composting, incineration and other methods, among which landfill technology occupies a large area; Composting technology has the disadvantages of volume reduction, reduction and low degree of harmlessness; Using garbage incineration technology has a high degree of reduction, but the investment is huge. Therefore, relying solely on a certain technology to deal with garbage is not the fundamental method to solve the garbage problem that is suitable for China's national conditions.
According to the characteristics of municipal solid waste in China, and from the viewpoint that garbage is a kind of misplaced resource, this project has developed a new technology and process of garbage treatment and recycling with low investment, high treatment efficiency and low cost-energy self-sufficient municipal solid waste comprehensive treatment and utilization system. According to the different components and physical and chemical properties of garbage in China, different garbage treatment technologies are organically combined to achieve the goal of reduction, reduction and harmlessness, and at the same time, the treatment cost is minimized and the garbage resources are comprehensively utilized as much as possible.
The process of simultaneous application of multiple technologies is scientific and reasonable.
On the basis of studying the composition of domestic waste in Boluo county, the researchers of this project put forward a system integration technology that combines sorting, organic waste fermentation, fertilizer processing, combustible pyrolysis-incineration, gasification power generation, inorganic waste landfill and other processes:
(1) Pre-sorting process
Recover recyclable materials from municipal solid waste through classification, such as renewable plastics, metals, waste paper and glass; Combusting separated combustible materials; Fermenting the sorted perishable organic garbage, and making the treated organic garbage into organic fertilizer; Inorganic waste can be used for landfill, paving or soil improvement (fine inorganic waste).
(2) Fermentation technology
Through the action of microorganisms, urban organic waste can be harmlessly decomposed into organic fertilizer, which can provide organic fertilizer for agriculture. Rotten organic waste comes from spontaneous combustion and returns to nature, thus maintaining the ecology of nature. The process can adopt rapid aerobic fermentation and high temperature ripening, and the treatment period is 15 days. The waste gas produced by closed fermentation is concentrated and discharged at a high level, and the exudate produced in the fermentation process is recycled without wastewater discharge.
(3) Organic waste treatment and fertilizer production process
The way out for urban organic waste treatment is to produce fertilizer. The successful sale and wide application of fertilizers have enabled waste treatment to proceed smoothly and achieved certain economic benefits. In terms of product quality, besides the quality of compost, the treatment of organic waste is also very important. The treated organic waste is processed into fine powder fertilizer by secondary screening, making coarse compost or drying, which can be used in paddy field, dry land and various crops. In addition, it can also be made into organic-inorganic compound fertilizer, which not only has obvious yield increase effect, but also can improve the utilization rate of chemical fertilizer.
(4) Incineration process
Incineration is characterized by rapid reduction, which is suitable for the treatment of combustible organic waste. This treatment technology uses combustible organic matter separated in the separation process for incineration. Because the garbage used for incineration has low moisture content and high calorific value, there is no need to increase auxiliary combustion during incineration, and the generated heat energy is used for fertilizer making and drying, which can save energy.
The process adopts pyrolysis and incineration technology to reduce the volume and quantity of combustible organic waste. Pyrolysis incineration is an advanced incineration technology developed internationally. This technology takes advantage of the high volatility of organic matter in garbage. First, the garbage is pyrolyzed (or gasified), and then the volatiles are released for gas phase combustion. Through pyrolysis, gasification and incineration, dust, NOX, SOX and HCl in flue gas are removed and washed to ensure that the tail gas reaches the standard.
(5) Gasification power generation process
The garbage gasification-internal combustion engine power generation technology adopted by Guangzhou Energy Institute of Chinese Academy of Sciences has the same principle as pyrolysis (gasification) incineration. Combustible gas burns at high temperature in internal combustion engine, which can completely burn harmful macromolecular organic substances and generate small molecular harmless substances such as CO2 and H2O. The process has the characteristics of small installed capacity, low investment and flexible and convenient start-up. This process is the key link to reduce the production cost.
(6) Landfill technology
The original landfill facilities are used in the landfill part of the system.
Technical innovation overcomes difficulties, and technical integration is unique.
A series of key scientific and technological problems have been solved. Mathematical simulation of pyrolysis and incineration and amplification effect of pyrolysis and incineration gasification equipment: Research on gasification and power generation technology and equipment development of organic wastes: Formation mechanism and control method of pollutants during heat treatment: Research on integration, optimization and control of technologies such as sorting, composting, pyrolysis and incineration heating, gasification and power generation, and water gas residue purification.
Through the original unit processing technology. Pyrolysis incineration is a waste incineration technology. On the basis of previous research, our hospital developed a strong cyclone pyrolysis incinerator to make the combustible gas generated by pyrolysis burn at high temperature and minimize secondary pollution. Gasification power generation system is a practical system that uses special gasifier (independent property right) and internal combustion engine to generate power according to the properties of separated combustible garbage.
Comprehensive integration technology is adopted: garbage sorting, composting, pyrolysis and incineration for heating, gasification and power generation and fertilizer production are integrated for the first time, and the process configuration is optimized. The overall level is in the leading position in China, which has laid a theoretical and practical foundation for large-scale promotion in the future.
Pay attention to close cooperation during construction, and implement enterprise management after production.
The project adopts the mode of combining college, land, institute and enterprise, which gives full play to the advantages of partners and provides a successful mode for the transformation of scientific and technological achievements in the future.
Strong alliance to ensure advanced technology. This project is led by Guangzhou Energy Institute and combined with Chengdu Institute of Biology to ensure the advanced nature and reliability of the developed technology.
Work closely with local government to ensure the progress of the project. The project division of labor is determined by all parties through coordination. The overall responsible unit of the project is Guangzhou Energy Research Institute, and has signed relevant contracts and task books with Boluo county government and enterprises respectively, clarifying their respective responsibilities.
Operate demonstration projects in the form of enterprises. After debugging and technical training are completed, the demonstration project will be handed over to the enterprise for operation. Boluo has established a special project company, which is jointly established by the local government, investment enterprises and scientific research institutes.
Establish joint ventures and speed up technology popularization. Cooperate with enterprises with investment strength and extensive social relations in the society to set up a special environmental protection company-Yuexi Environmental Engineering Co., Ltd., which is responsible for technology promotion. The institute is mainly responsible for providing technical support, and the partners are mainly engaged in market development.
The investment and operation costs are low, and the market prospect is very broad.
With the development of national economy, garbage disposal has been put on the agenda of governments at all levels. Traditional garbage disposal has the problems of high operating cost and low output (landfill has no output at all). Even if the government invests in construction, the high annual operating costs will become a huge burden for local governments. Compared with other or traditional garbage disposal methods, the integrated technology of municipal solid waste recycling and energy utilization led by Guangzhou Energy has obvious advantages of eliminating disadvantages and promoting benefits, and the investment and operation costs are lower: the system investment cost is equivalent to 1/5 of foreign technology and 1/2 of other domestic technologies, in which the equipment investment cost is below 1 10,000 yuan/ton. According to the garbage disposal capacity of 6,543,800+500,000 tons/day, Corruptible organics will produce coarse compost products from garbage entering the factory to fermentation. Using the energy of combustible organic matter, the operating cost is about 20 yuan/ton.
Guangzhou Institute of Energy, Chinese Academy of Sciences has made a new breakthrough in the engineering demonstration of the comprehensive integration technology of municipal solid waste recycling and energy utilization, which has played a good demonstration role in the recycling of garbage in China and surrounding areas, and provided a mature technology and its transformation platform for the development of this field. It can be predicted that with the rapid economic development of China and Guangdong Province, the comprehensive integration of municipal solid waste resource and energy has a good market prospect in the whole province and even the whole country. Based on China's annual garbage output of 65438+500 million tons, if half of them are treated by self-sufficient composting system, the total demand will reach more than 36 billion yuan (excluding the cost of land acquisition and landfill construction), and the market scale is also expanding, because the garbage output is still increasing year by year.