(TN&MT) – Waste treatment, in which solid waste (CTR) is an important task that determines the environmental quality and socio-economic development of the country. Choosing the right treatment technology suitable for the locality is important to contribute to environmental protection (environmental protection), bringing the country to develop in a modern, civilized and sustainable way.
Burning and burial are obsolete
With the current volume of waste, the Government and local authorities are looking for a technology that complies with the principles and criteria set by the legal documents. That is, choosing solid waste treatment technology must have access to advanced technologies and experiences in handling solid waste at home and abroad; simple technology but not backward, ensuring effective, safe and non-polluting treatment; prices are acceptable in local conditions; Try to recover the value of CTR to recreate resources.
According to Vietnam Construction Code on Urban Planning (QCXDVN 01/2008), it is recommended to apply advanced technologies, develop clean technologies, domestic research and manufacture technologies, and prioritize reuse. , solid waste recycling, minimizing the volume of landfill CTR (<15%), especially in urban areas that lack land fund for landfill.
Legal documents on the selection of solid waste treatment technology are available, but we have yet to find a technology that meets the requirements. According to the statistics of the Ministry of Natural Resources and Environment, currently, CTR is mostly treated by landfill method, typically 95% in Hanoi and HCMC. HCM 76% and a part is treated by burning method. Both of these methods do not bring about environmental-economic efficiency. Because it causes waste of land resources, State budget; waste of recyclable waste, causing long-term environmental pollution.
Alternative technology: Pyrolysis Alternative technology: Pyrolysis
Scientists say that Vietnam can use the methods that the world tends to choose, such as electricity generation technology and pyrolysis technology. These are the two best solutions to recover values from waste and reduce environmental pollution effectively. These two technologies will bring many long-term values and benefits to the development of industrial parks and urban areas in Vietnam.
According to Mr. Nguyen Thanh Tai, Director of New Technology Limited Company, for Vietnam, the pyrolysis method is more suitable because of this technology, investment capital and low operating costs, high environmental efficiency. Meanwhile, burning electricity requires more money and higher costs. This technology is very suitable for plastic waste disposal. Mr. Tai emphasized: Plastic waste is difficult to decompose causing many environmental problems such as loss of land due to landfill, long time of decomposition causing environmental pollution, expensive processing costs … but it is a renewable energy source. created when using pyrolysis technology to recycle into oil. Based on the composition, structure, characteristics of plastic waste, environmental organizations around the world assess the thermal technology of thermo-chemical technology group, which is one of the best technology solutions available and promotion. The report used instead of other processing methods.
In the context of increasing plastic waste, this is the optimal treatment method. This technology allows recycling of mixed plastic garbage, plastic waste that has not been cleaned and contaminated such as: Plastic recovered from domestic waste, plastic from industrial garbage. At the same time, plastic waste can be recycled with different sizes, especially the treatment of large-sized plastic waste such as rolls or bales … The pyrolysis process of plastics with Cl components (such as PVC) will not Create dioxin as a burning method.
Waste treatment process by pyrolysis technology
Some opinions said that the application of recycling plastic waste pyrolysis technology has solved environmental problems and solved the “renewable energy” problem when providing “green energy” products to society. oil and fuel coal. The pyrolysis process of polymers (plastic, rubber …) produces gases (syngas), liquid (tar), and solids (char). These products can be used as fuel, petrochemicals and monomers.
With this method, the material is fed into the rotary kiln along with the pyrolysis catalyst at the specified rate. The heating furnace uses pyrolysis oil and gas from the system to burn indirect heating for the rotary kiln. Under the effect of heat and catalytic agents in anaerobic environment, the plastic will be thoroughly cracked into a gas body and transferred to the condenser. The remaining solid is powdered coal that will be removed from the rotary kiln by a sealed screw.
During the pyrolysis process, the rotary kiln is always provided with a negative pressure thanks to the vacuum device being placed at the end of the system after the condenser. The hydrocarbon fraction from anaerobic cracking rotary kiln is transferred to a three-stage condenser with vacuum evaporator and indirectly cooled by cold water.
When the temperature is lowered below 35 ° C most hydrocarbon gases will condense from the gas to liquid (pyrolysis oil) and separate from the gas stream. The remaining non-condensing gas will be transferred to the heating furnace.
The heating furnace uses two Olympia automatic oil burners (Japan) to burn pyrolysis oil, start indirect heating for cracking rotary kilns. When cracking occurs during the cracking process, the gas (non-stop gas) will be generated, circulated and burned with two Olympia automatic gas burners to continue heating the cracking rotary kiln until the end of the cycle. pyrolysis. During the coal removal process, the furnace head is fitted with a dust recovery device by filtering the dust sleeve, which helps to clean the coal.
Environment-friendly recycling technology, applied in a closed, highly automated model, low energy consumption. The technology does not emit toxic gases such as dioxins and furans, using environmentally friendly chemicals, all waste is recycled 100% without discharging waste into the environment.
– Plastic waste pyrolysis technology was invented in the early 1970s, the time of large-scale plastic production boom in Europe. The technology was further researched and developed until the 1980s and 1990s when Japanese scientists created new innovations to improve the technology when using plastic pyrolysis recycling catalysts and putting technology into Application of industrial practice. Pioneer is Ebara (Yokohama) and Tsukishiama (Kitai).
– In Vietnam, pyrolysis technology has been interested in Vietnam for the last 4 – 5 years. At present, there are a number of research topics of scientific institutions such as Institute of Mechanical Research, Petroleum Institute, Petrochemical Center – Ho Chi Minh City National University, Science and Technology Enterprises New … Some factories in the field of environment have been implementing applications such as Hai Duong Green Environment Company, Binh Phuoc Environmental Company, Hue Phuong Green Environment Company, … initially obtained the results positive results.