Enhancing kiln control

Enhancing kiln control
Published: 30 November 2012


The major costs of clinker production are incurred in kiln pyro-processing, so it’s no surprise that this part of the process received more attention than any other. To-date, the trillions of tonnes of clinker manufactured have been produced in plants controlled mostly on elemental chemical data. Bogue equations construct hypothetical mineral compositions that ignore the heat treatment in the kiln. 

Kiln control with COSMA
on-line Mineral Analyser

Fuel combustion specialist FCT International is first with the COSMA mineral analyser, which is designed and developed to measure and report the mineralogical composition of materials being processed, online, in real time.
 
A complete analysis of clinker mineralogy at the cooler reveals a live picture of the pyroprocess and allows corrections to the various parameters that affect clinker quality, before the quality is compromised.
 
With free lime, NOx and fuel consumption being issues critical to the cost-effective operation of a clinker kiln operation, a clear understanding of clinker mineralogy gives best control possibilities. Thus, the complete mineral picture presented by the COSMA analyser enables free lime, NOx and fuel to be mapped and correlations determined so that effective control strategies may be implemented. 
 
Fuel consumption is major casualty of a hard-burn kiln. However, FCT notes that kiln control based on COSMA mineralogical data can increase the operating level of free lime from under 0.5 per cent to an average of over one per cent. This can reduce fuel consumption by some five per cent as the burn zone temperature is decreased. A corresponding five per cent increase in production is then available from the kiln.
 
NOx emissions are obviously tied to kiln burning, the levels primarily dependent on how hard a kiln is being burned.  Better kiln control available from the clear picture presented by a COSMA analyser can reduce emissions by as much as 40 per cent, state FCT.
 
The quality of clinker produced from control models based on a  comprehensive live picture of the pyroprocess will be much improved and consistent, FCT underlines, with dramatic implications for cement milling process and final product performance.  Mill throughput can be maximised with a softer-burned clinker and 28-day strengths can be consistently produced.
 
With kiln operations running under optimum conditions, increased profitability is guaranteed. Therefore, the COSMA analyser helps address challenges relating to pressures on fuel prices, NOx emissions and quality assurance.