Pyrolysis (Thermolysis) as a Preferred BioSynENERGY Technology for Generating Value from Waste
Incineration (combustion/burning) of waste material converts input waste into energy and ash but is always associated with emissions of greenhouse gases, unhealthy particulate matter and toxic residues. Even with the most advanced and sophisticated emission controls, combustion can never achieve the environmental standards available with the best engineered pyrolytic platforms. In contrast to combustion/incineration, pyrolytic/gasification "bakes" waste materials at relatively low temperatures (generally, 300 to 650 degrees centigrade) under highly controlled conditions that reduce or eliminate oxygen - so waste conversion is conducted without combustion.
Instead, a variety of waste materials are broken down into smaller carbon-containing compounds; these molecules are collected and sold "as is" or further cost-effectively transformed into valuable end-products that can be used to generate energy (electricity, heating and cooling), oils/solvents, recyclable materials for resale (such as metals) and other bio-products such as biochar - all of which can create substantial profits and new jobs while generating carbon credits and environmental benefits.
The process of pyrolysis (or thermolysis) of waste materials takes place in special chambers with reduced or no oxygen, resulting in thermal decomposition of all organic materials without combustion. Most pyrolytic processes produce solids (char and ash), gases and oils. Depending on the waste feedstock and pyrolysis technology used, these end-products can be sold "as is" or cost-effectively converted into other by-products of greater commercial value. When pyrolysis (a relatively low temperature process) is coupled with gasification (a higher temperature process, but still combustion-free), organic waste compounds into a clean "synthetic gas" (often called syngas or producer gas) that can then be combusted to create steam to generate electricity in special gas engines or turbines.
Conventional incineration/combustion in conventional power plants - whether burning coal or natural gas - also produce steam to drive turbines to generate electricity; however, they operate at lower efficiency and produce environmentally destructive emissions. Coal burning also produces significant amounts of "fly ash", an unavoidable consequence of combustion that can contain toxic metals (including arsenic and mercury); the recent accidental spillage of millions of gallons of stored fly ash in Tennessee underscores the many environmental threats associated with coal burning.
In contrast to incineration/combustion, pyrolysis is the decomposition of organic materials during heating in oxygen-free atmosphere to produce gas, liquid and solid residuals. Decomposition products of the pyrolysis depend upon the heat, pressure and time the material is held within the vessel.
There are many variations of pyrolysis technologies in commercial operation; they vary greatly in their efficiency, cost-effectiveness, environmental impact and range of converting waste materials to profitable products. Some of the advantages of pyrolysis over incineration/ combustion include:
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Greatly increased possibilities for recycling:
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Emissions from pyrolysis are considerably lower:
- depending on the technology variant employed, up to 99% of the material treated is recovered, with virtually no effluents escaping into the environment;
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By displacing fossil-fuels, waste pyrolysis can help meet renewable energy targets, address concerns about global warming, contribute to achieving Kyoto Protocol commitments and generate renewable energy/carbon credits for sale or trading.
- Pyrolysis systems have been developed for a wide range of capacities and wastes, including recovering materials and energy from residues left from materials recycling e.g. electrical and electronic scrap, tires, mixed plastic waste and packaging residues.
The following table describes some areas of proven (commercialized) implementation of pyrolysis technology.
|
Application |
Raw Materials |
Product of the Pyrolysis |
| Waste-to-Energy |
Agricultural and Food Processing Waste
Waste Plastics
Waste Tires
Municipal Solid Waste (MSW)
Biomass
Medical Waste |
Oil/Solvents
Carbonized Materials
Gases (e.g. butane)
Electricity |
| Carbonization System |
Wooden Chips
Organic Sludge |
Carbonized Materials |
| Drying System |
Organic Sludge
Waste Food |
Dried Materials |
| Soil Remediation System |
Contaminated Soil (dioxin, PCB, oil) |
Clean Soil
Recovered Materials |
Summary: BioSynEnergy recommends ONLY environmentally permitted, efficient, patented pyrolystic systems that have been proven to be safe and economical in operation. |
