Pyrolysis: Environmental friendly waste treatment
Pyrolysis technology practical applications
Sewage sludge pyrolysis
- Sewage sludge pyrolysis process is an effective reduction of the sludge (to ~10-15% of the initial amount) and neutralisation of organic toxic agents from the sludge.
No supplementary fuel supply is required for the normal operations: significant reductions of running costs
Initial sludge dewatering (to 30-35% moisture) followed by the pyrolysis process disposes waste and generates heat/electricity
- Char from the pyrolysis process has properties similar to brown coal and could be used as a bio-fuel
- Sewage sludge pyrolysis can also be used for recovery of such valuable material as phosphorus
The MSW pyrolysis plant accepts
Fresh raw garbage as collected from households and commercial facilities
- Sorted high calorific waste from Mechanical Biological Treatment facilities (RDF/SRF)
- Aged MSW from landfills (cleaning up open dumps)
MSW pyrolysis plant is a typical Waste-to-Energy pyrolysis plant with non-oxidized metals reclamation.
MSW with high food waste content will require preliminary drying. Energy for drying will be provided by pyrolysis itself.
Waste plastics pyrolysis
Energy recycling of this high calorific feedstock could be done in form of either oil recovery or direct electicity generation.
After pyrolysis in the rotary kiln pyrolysis gases are cooled down comdensing oil. Quality of the recovered oil can improved either by distillation or catalytic treatment of the pyrolysis gas prior to condensation. Recovered plastic pyrolysis oil can be used as diesel generator fuel or fuel for burners.
Pyrolysis of plastics can also perfromed through oxidation of the pyrolysis gas, recuperation of its energy in Heat Recovery Steam Generator and further elctricity generation by steam turbine.
Scrap tyres pyrolysis
Tyres have high calorific value which favours to pyrolysis of scrap tyres through pyrolysis gas oxidation and direct heat/electricity generation.
Solid residuals can be further processed at the pyrolysis plant generating more gas.
Pyrolysis gas can also be condensed recovering pyrolysis oil. The recovered oil and pyrolysis carbon black (CBp) require further upgrade for commercial use.
In both cases non-oxidized metal will be a by-product.
Tyres should be shredded prior to the pyrolysis.
Oil sludge pyrolysis
Proper treatment of oil sludge is essential since these waste materials are hazardous to human and environment.
The design specifications determine configuration of the pyrolysis system, i.e. whether to proceed with the oil sludge disposal and direct electricity generation or with oil condensing.
Gas cleaning system design will depend on oil content available from analysis.
Automotive Shredded Residuals pyrolysis
Automotive Shredded Residue (ASR) or car fluff generally consists of a mixture of plastics, rubber, glass, wood products, cloth, paper, foam, dirt, and electrical wiring, i.e represents a high calorific waste. The industrial ASR pyrolysis systems implements general MPSC scheme, performing pyrolysis followed by generation of electricity.
Solid fase contains also valuable metals to be further recycled.
Electronic waste pyrolysis
Electronic appliances bodies are made of different plastics and therefore represent proper feedstock for waste-to-energy pyrolysis. Printed ciruit boards is a mixture of organic resins, fiberglass, ceramics and metals.
During the pyrolysis the volatile portion of electronic waste is thermally decomposed. Energy of the pyrolysis gas is used for heat/electricity generation. Solid phase includes valuable metals which will be further recycled.
Since bromine flame retardants are used in electronic boards, the pyrolysis facility is equipped with extended gas cleaning.
Medical waste pyrolysis
Medical waste is a multi component hazardous waste. Main constituents of the medical waste are plastics, textile and polyvinylchloride (PVC).
Medical waste also includes needles, pathological wastes from surgery and autopsy, and pharmaceutical waste.
High calorific content of medical waste provides the condition for energy recovery and electicity generation.
Special loading device to pyrolysis kiln allows to treat unshredded medical waste
without preliminary sterilisation which is achived by high temperature in the pyrolysis kiln and a long residence time.
Poultry litter (animal manure) pyrolysis
Poultry litter consists of manure, bedding (saw dust and straw), and food remains. Daily fresh manure output may reach 15-17 kg per 100 birds.
Fresh manure is 75 percent water and the moisture evaporates while it is in the poultry house. Moisture content in dried poultry liiter is in the range 10-30%, while calorofic value 10-16 MJ/kg.
Pyrolysis of poultry liiter eleimintes odour issue, generates energy and produce solid fretilzer with main nutritients. The same approach is applicable to other types of animal manure.
Wood pyrolysis and Biochar production
Waste wooden biomass is pyrolised, and then pyrolysis gas is used for direct electricity production.
Biochar recovered from non-contaminated wood is a valuable product and can be used as
- Soil improvement agent
- Fuel briquets
- Component in metallurgy
Contaminated soil pyrolysis
Pyrolysis technology is efficiently used for the thermal cleaning of contaminated soil.
Several built soil remediation pyrolysis plants (capacity 150-250 tpd) successfully treat soils, which have been heavily contaminated with organic pollutants such as dioxin, PCB, oil, mercury. The cleaned soil is then re-utilized.
Olive waste pyrolysis
Olive waste is usually a mixture of crushed olive pits, olive husk, pulp, some pomace oil. it is destroyed in big amounts in oilve oil production countries, while olive waste is quite calorific waste and can be processed by pyrolysis for energy generation.
Olive pits can also be utilized for biochar production.
Laminated materials pyrolysis
Pyrolysis is successfully used for disposal of laminated materials like TETRAPAK, pharmaceutical and other packaging, aluminium panels, etc.
Pyrolysis process results in reclamination of metal and generation of energy from the other component like plastics and/or paper.
Activated carbon regeneration
Pyrolysis of spent activated carbon brings considerable savings, for instance, to drinking water cleaning facilities.
Contaminants are transferred into gaseous phase and consequently destroyed by downstream pyrolysis. Regenerated activated carbon is solid phase pyrolysis product which is ready for re-use.