ZZS wind sifter - separation of substitute fuel

According to the Federal Statistical Office, more than 50 million tons of industrial and commercial waste were generated in Germany in 2019. This represents an enormous burden for the environment. A large part of this waste is stored in landfills. Incineration in the waste incineration plant is also a popular disposal method. However, there are also ways to make the waste usable. For example, there is the possibility of obtaining energy from them and using them for cement production. Commercial and industrial waste are ideal for this.

For most people, garbage is a worthless item that just needs to be disposed of as quickly as possible. However, the waste is often not quite as worthless as it appears at first glance. Many of the substances that are no longer needed contain a lot of energy. For example, waste contains plastics, paper, wood and some other materials that can be used as fuel. This can not only pay off financially. The environment also benefits from it. On the one hand, in this case it is not necessary to store the waste in landfills. Therefore, the landscape is not polluted in the process. On the other hand, this energy makes it possible to replace fossil fuels. The corresponding materials are called substitute fuels.

Using the waste as fuel is not a fundamentally new idea. This has been implemented in waste incineration plants for decades. However, the waste is usually incinerated unsorted. However, since it also contains many non-flammable substances, this means that the combustion process cannot run optimally. This severely limits the possible uses. It is therefore very important to separate the flammable substances beforehand. This enables a better combustion process and thus many additional application possibilities. 

Sorting is usually carried out on the basis of the density of the substances. Light materials like paper or plastic are usually flammable, while heavy materials like metal or glass are not suitable for combustion. Most waste, however, only contains around 20 percent light substances. The vast majority of 80 percent is heavy waste. This also shows how important sorting is, as most of the waste is unsuitable for energy generation. However, the heavy waste can often be recycled in other ways. For example, after this pre-sorting, it is much easier to separate metals or glass and then to recycle these materials.

To sort the waste based on its density, you can use the WINDSICHTER ZZS from TRENNSO-TECHNIK^®. This device has a so-called zigzag sifter. This is a vertical channel that has several kinks. It is possible to introduce the waste into the classifier via a rotary valve. A strong air current is applied here and fed into the duct from below. This principle already leads to a separation of the waste materials based on their density. The air flow pulls the light parts upwards with it, while the heavy waste material remains on the floor.

The special zigzag shape of the sifter leads to an even more reliable separation. It often happens that heavier and lighter fabrics stick to each other. If they hit a kink, however, they are directed to the side and hit the side wall with great force. This leads to them becoming detached from each other. By repeating this process on multiple kinks, there is a very reliable separation. It is possible to regulate the speed of the air flow. This allows the separation of the materials to be precisely adapted to the requirements.

After separating the waste, it is possible to use it as an energy source. They are used particularly frequently in cement works. Cement production requires a lot of energy and leads to significant CO2 emissions. However, the use of substitute fuels from waste makes it possible to significantly reduce the need for fossil fuels. As a rule, so-called co-incineration is used, in which the waste materials are burned together with fossil fuels.