Nowadays there are several efficient technologies and equipment to solve one of the major environmental problems: the treatment and disposal of polluting Municipal Solid Waste (MSW).
Waste treatment equipment may generate energy in the form of steam, hot water or electricity, which can be recovered for the production processes of the plant.
What is waste-to-energy technology?
Waste-to-energy refers to technologies designed to recover energy from any type of waste, with a focus on the production of thermal or electrical energy (or both).
Such systems can be based on a number of different technical solutions for recovering energy from waste, including:
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Incineration
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Pyrolysis
The common denominator of all these technologies is their capacity to produce steam using the residual heat from the gases generated by the processes described above.
In turn, the production of steam makes it possible to:
Supply heating in urban centres, in line with the district heating model.
Supply a variety of industrial processes
Produce electrical energy via steam-powered turbines for self-consumption in industrial plants and/or sale via classic “sell to grid” models
Another valid technical alternative, albeit one that only applies to pyrolysis processes, is the direct production of energy via syngas-powered turbines. This is rather less common, due to the unique nature of pyrolytic reactors and the high CAPEX required for such facilities; however, these solutions guarantee outstanding performance, heat balance close to autothermal operation, very low OPEX and, as a result, a short return on investment.
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What is incineration?
Direct combustion, also known as incineration, is the process by which organic matter (always comprising carbon and hydrogen) reacts with an excess of oxygen to produce carbon dioxide and water, with a minimal amount of ash as a by-product.
This process takes place in combustion kilns, which must maintain a minimal amount of oxygen (usually 6 %, although 11 % may also be required) at the output in order to ensure complete combustion. If there is insufficient oxygen, the combustion reaction will not be complete and compounds may be generated that are not fully oxidised, such as monoxides and other pollutants (e.g. SOx, NOx, HCl and particulate matter).
It is a process that must take place at a high temperature (800 °C – 1100 °C), depending on the amount of halogenated elements in the waste (chlorine, fluorine, bromine).
Direct combustion generates energy in the form of heat. This energy can then be used to generate steam and electricity via turbines, power for the plant’s own consumption, hot water for domestic heating, and other energy recovery applications.
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What is pyrolysis?
Pyrolysis is the chemical decomposition of organic compounds in the absence of oxygen. The process usually takes place at temperatures between 450 °C – 600 °C at negative pressure, and aims to break the long hydrocarbon chains into shorter ones. During this process, syngas (or synthesis gas) is generated by the volatile compounds that would normally be sent to a combustion chamber for oxidation. The process also generates a solid, carbon-rich waste material known as char. Pyrolysis is the first stage in the gasification phase for combustion.
It can be carried out in two types of kiln: rotary and static. Rotary kilns are recommended for large volumes of waste (1-5 t/h) and static kilns for smaller volumes.
What are the advantages of waste-to-energy systems?
- Flexibility regarding the technical solutions available.
- Flexibility regarding the type of waste and the method of feeding it into the system and processing it.
- Fully scalable solutions.
- Turnkey projects in which Tecam assumes total responsibility for the design and provides full guarantees.
- Solutions for the continuous monitoring of emissions, which local authorities require in order to permit these types of facility to operate.
Please contact us today for further information on waste-to-energy solutions. We’ll be happy to help.