Scandinavian Biofuel

Scandinavian Biofuel Company

Microwave assisted pyrolysis for waste treatment and renewable energy

Microwave Assisted Pyrolysis

Pyrolysis as principle describes the chemical decomposition of hydrocarbon materials by heating in the absence of oxygen or any other reagents. Pyrolysis is the ideal treatment for organic raw material. The process has been known for centuries. A well-known example is the gas works, where coal is heated to produce coke, town gas and hydrocarbon liquids.

The Microwave Assisted Pyrolysis process is well suited to recycle a variety of waste fractions such as tires, sewage sludge, agricultural waste, waste wood, electronic scrap, cables, plastic waste etc.


Process

Many projects for the pyrolysis of organic waste, in particular plastic and rubber waste such as car tires, have been designed and realized. Very few of these projects have however been successful:

- The quality of the end product depends on the ability to control the temperature through the whole feedstock. Organic materials are in general poor heat-conductors, so this is not easily achieved by conventional pyrolysis techniques. The poor quality of the end product prevents reasonable prices to make the process economical viable.

- Process efficiency and economics depend on continuous processing. This is difficult or impossible to achieve by conventional pyrolysis techniques, as the even heating of moving material is very difficult. In particular will feedstock containing plastic or rubber represent a challenge, as these materials get sticky when heated.

The Microwave Assisted Pyrolysis technology eliminates the described problems. The microwaves heat by exciting the individual molecules in the organic material. The heating is very accurate and even through the feedstock, and the heat control can be given within very narrow margins.


Advantages

The Microwave Assisted Pyrolysis is, compared to incineration, easily controllable. Incineration is complicated and expensive to control, and will usually create harmful or toxic components that have to be removed from the flue gas.

The pyrolysis is a process with no oxygen present. Consequently oxides cannot be formed. For the same reason dioxins cannot occur, as the formation of dioxins is dependent of the presence of oxygen.

The process is completely enclosed, and all products are collected and duly treated without any emissions to the environment, called dry distillation process. As no oxygen is added to the process, the produced gas will be a concentrated fuel gas with high calorific value.

The feedstock is brought into the pyrolysis reactor through air locks purged with inert gas to prevent oxygen to enter the reactor. It is then heated by means of microwaves to a temperature where the bonds between the solids and the volatiles in the material are broken. The volatile fraction consists of a vapor that is separated into gases and fluids by condensation.


Project Examples

Project examples with maximized electricity production.