Long kiln technology can still be found in older cement factories in the USA, Russia, Asia and South America in particular. But even in these countries, ever lower emission limit values are forcing plant operators to apply secondary measures for NOx reduction in exhaust gas. To reduce the nitrogen oxides in the flue gas of such plants, a special injection system needs to be retrofitted. Only in this way the reagent can be brought into the optimum temperature range inside the rotating kiln. The practical implementation of this process requires a high degree of technological and process knowledge.
In the case of plants with conventional long kilns, the challenge is above all to realize an injection system that is able to successfully master the interface between the stationary valve skid unit and the rotating kiln. Due to the eccentricity of the long kiln, the center of kiln entry moves during operation. It is moved further still by thermal expansion. These factors and their consideration alone shows just how complex the task is.
A further challenge is the selection of the material for the nozzle lances and other components in the kiln. These are constantly rotated during the firing phase by the hot material within the kiln.
The scope of delivery for these injection systems covers the customized design and supply of valve skid units, pipe systems for the decoupling of rotating and static components, pipelines in and on the kiln as well as injection lances within the long kiln.
Lechler has already installed more than 15 injection systems in the USA which are even below the required emission limit values and at the same time comply with NH3 slip requirements.
Lechler nozzle lances and systems for different specified limits, which can grow modularly to meet your specific requirements.