What is hazardous waste?
Hazardous waste refers to industrial or municipal waste that due to its toxicity and hazardousness must be treated using extremely safe methods. Of course they should not be disposed of in landfills. Such types of waste include those containing phosphides, isocyanates, alkali metals and acids, which form gases during combustion (e.g. chlorine forms hydrogen chloride, HCl), along with those containing mercury, etc.
A specific solution to eliminate hazardous waste
Because this kind of waste is considered hazardous, it must be thermally incinerated at a very high temperature (1100°C) for two seconds in a combustion chamber with minimal oxygen content. This ensures complete oxidation and destruction.
To carry out this process, at Tecam we normally use rotary or static kilns, depending on the type of waste to be treated. Rotary kilns are used most frequently, as they are designed to treat a wide variety of solid waste.
Controlled pyrolysis
Controlled pyrolysis or gasification is the process by which organic matter is partly oxidised. The oxygen content is regulated, with less than the stoichiometric amount added in order to be able to control the combustion process. The operating temperature of controlled pyrolysis is usually higher than it is for regular pyrolysis (750°C) due to the fact that partial oxidation takes place, which generates energy and increases the temperature inside the kiln.
This process also generates syngas, which is a mixture of carbon monoxide, hydrogen, carbon dioxide, water and nitrogen. Additionally, it generates solid waste and inert, non-combustible materials such as heavy metals.
Where is pyrolysis technology applied, and what are its advantages?
These systems are used to treat municipal waste, plastics and sewage sludge.
They represent the first phase in the combustion process and are intended to achieve gasification (i.e. extract the volatile compounds from the waste) so that it is easier to oxidize the waste in the secondary oxidation chamber.
Moreover, since this process generates syngas, it can then be used to produce energy and/or reused in other processes.
What does pyrolysis equipment consist of?
Pyrolysis systems consist of the following elements:
- Pre-treatment: this may consist of drying or other preparatory measures.
- Ram feeder: this is a series of valves that make it possible to control the feeding of the waste. The main purpose of this device is to allow the waste to enter while preventing air from entering the kiln from outside.
- Rotary or static kiln: this kiln has a cylindrical, horizontally positioned body that rotates on its axle, allowing the solid waste inside to decompose.
- Air inlet fan: this controls the amount of oxygen. It usually operates on the basis of 30% of the stoichiometric amount, i.e. only the stoichiometric amount of oxygen required to oxidise 30% of the waste is added.
- Extraction of ash and fixed carbon: the waste material contains a certain amount of compounds that cannot be gasified, and generate ash and fixed carbon (char) as a result. Furnaces must be fitted with a device to extract these waste materials, cool them down and send them on to be further treated.
At Tecam we are specialists in waste valorization through pyrolysis or incineration processes, for the sectors that are most sensitive to environmental impacts.
We drive sustainable productivity and innovation for industries with more extensive and more complex needs.
If you are interested in obtaining further details on this topic or learning more about Tecam environmental solutions for emissions treatment and waste valorization, please contact us – we will be happy to help you: +34 93 428 11 54 or info@tecamgroup.com
