With experience of over 40 years, the cement industry is a well-known user of various alternative fuels. Subcoal® has been used on a number of different kilns in Europe, with some surprising new ways of substituting fossil fuels. Not only does the quality of Subcoal® give added value in the process compared to traditional substitute fossil fuels, Subcoal® also has logistic advantages in terms of handling and dosing, read more about Subcoal® logistics here (link).
Below a short summary of proven ways to use Subcoal® in cement kilns.
Short pellets for the main burner
Short Subcoal®, also known as Subcoal® fluff is used in the same way as normal fluff, SRF (solid recovered fuel), EBS (ersatzbrennstof) or CSR via existing feeding systems on the main burner. Depending on the kiln type and size, the short pellets can be used in a similar way to fluffy alternative fuels, even though the density is higher. This is of course depending on the kiln system and kiln settings , as higher density could pose an issue. This can be discussed with our team of experts.
Short pellets are in most cases much dryer than traditional alternative fuels, plus these pellets have been pressed through an 8mm dice which ensures there are no large contaminates which can block the burner or feeding systems. Especially for kilns which import alternative fuels, Subcoal® fluff also makes logistics and handling much easier as no debaling is required.
Subcoal® in various sizes has been successfully applied in kilns without a calciner or kilns with specific demands in their calciner burning chamber. Depending on the configuration of the kiln, pellets can be produced on the optimal density to allow them to burn in the correct zone. This allows kilns to either substitute fossil fuels or more difficult alternative fuels such as tyres with Subcoal.
Various applications have proven that the pellets are heavy enough to prevent them from being sucked up into the bottom cyclone, but they are light enough to prevent them from falling into the clinker.
To produce an alternative fuel with a very fine particle size has proven very difficult. Not only from a commercial point of view, but also from a logistics and handling point of view. Subcoal®, however, also offers a solution for this problem, as the hard pellets allow very fine grinding.
Various types of mills can be used to easily mill Subcoal® down to a < 5mm powder which ensures very quick burnout times. Milling a pellet on site gives extra handling for the end user, but it does offer the possibility to substitute up to 100% of the fossil fuel used at the main burner.
N+P is very experienced in many methods of grinding and we are happy to help you further with these possibilities.
View infographic showing how Subcoal® is used on a cement kiln
NEW WAY OF SUBSTITUTING FOSSIL FUELS
The quality of Subcoal® gives added value in the process to substitute fossil fuels and Subcoal® also has logistic advantages in terms of handling and dosing.