Alternative fuels provide opportunities for reducing production costs. Further benefits are environment-related: reduction of emissions, utilization of energy from alternative fuels etc.
Fuels that are classified as alternative fuels are different kinds of plastics, paper, wood chips, organic solvents etc. Speaking about cement industry, even shredded car tires are used, as chips fed into the riser duct helping to keep the temperature high enough for pre-calcination. Over the past 30-40 years, cement companies have developed strong know-how on the use of alternative fuels. This know-how is recognized at national level in many countries.
Changes that appeared in the process
It is of great interest to be able to predict the changes that will occur in the burning process when alternative fuels are used (instead of coal for instance), the heat transmission in the kiln and chemical changes, such as the composition of raw meal and parameters controlling the clinker burning process. It is also important to find out how alternative fuel affects the product that leaves the clinker kiln.
The effective heating value (LHV) is an issue that, combined with the higher need for oxygen may have surprised the kiln operators the first time tires were used as fuel in the clinker manufacturing process. But effective use and great efforts within the research and testing programs made the world more familiar with the new fuel.