How COSMA on Your Kiln Can Improve Your Plant's
Performance

BENEFITS OF CLINKER ANALYSIS WITH COSMA

COSMA - Technical Differentiation
The use of XRD analysers with Rietveld capability to directly measure mineralogy is now widely accepted in the cement industry as the most effective way to monitor product quality. However, laboratory-based analysers, even robotic systems are limited by the small, possibly unrepresentative, quantities of sample materials made into tablets for analysis. Furthermore, there is a significant time lag between taking the sample, analysing it, and providing the data to the plant operator or expert system for control action.

COSMA differentiates itself from contemporary laboratory-based XRD analysers in that it not only measures the mineralogy of clinker and cement directly, but it also does so continuously and in real time. COSMA analyses up to 250kg of material in a day, thus presenting a clear and representative picture of the entire process. COSMA thus provides the operator or expert system with the necessary information to initiate timely control actions and closely control product quality and the process in general.

COSMA - Benefits of a Clinker Installation
COSMA realizes substantial benefits that can be measured in real dollar terms. COSMA analyses crushed and ground clinker from the kiln or cooler.

COSMA displays clinker mineralogy in a real time, continuous trend, which can be directly correlated with other process variables. This direct insight into kiln performance allows the operator to optimise materials and plant operation, and achieve maximum production, highest quality and minimum cost.

COSMA measures free lime and other clinker minerals directly, continuously and in real time. With this data, the operator or expert system can initiate the appropriate corrective actions to control free lime closely, thus reducing free lime variability and promoting more stable and, generally, softer burning. Furthermore, with the more current information provided by COSMA, operators are enabled to permit a tighter move to greater optimisation, leading to real cost advantages afforded by an assured knowledge of free lime content.

Free Lime Excursion Cement Plant Control



Because COSMA measures all relevant minerals, the operator can diagnose the cause of a free lime excursion and take appropriate and timely corrective action.

Following are examples of specific ways in which the analysis of clinker by COSMA can impact directly on plant performance and, therefore, plant profitability.

  1. Lower fuel costs or higher production
    In general, a 30°C drop in kiln temperature means a fuel saving of 3%, or the corresponding increase in clinker production. This same change in temperature leads to a 0.3% increase in average free lime. Thus, closer kiln control with COSMA resulting in a 0.3% increase in average free lime will lead to a 3% reduction in fuel use for the same level of production. Alternately, if the kiln is fan or heat load limited, a 0.3% increase in average free lime will allow the kiln to produce 3% more clinker for the same amount of fuel use. COSMA thus generates benefits in the form of lower fuel costs or higher revenue from increased product sold.


    Following is an estimate of the cost/benefit for 1,000,000tpa clinker plant, with fuel costs of $10/tonne and in which average free lime increased from 0.7% to 1.2% through closer kiln control via COSMA. Cement price is $50 per tonne. (Take the conservative position that the 0.5% increase in average free lime will result in a 3% saving in fuel usage.


    Fuel savings
    Current annual fuel costs = 1,000,000tpa * $10/tonne = $10,000,000
    Annual fuel savings @ 3% = $300,000


    Production increase
    Current annual plant revenue = 1,000,000tpa * $50/tonne = $50,000,000
    Annual production increase @ 3% = 30,000 tonnes
    Annual revenue increase @ $50 = $1,500,000


  2. Increased clinker grindability
    Clinker with higher free lime content is more reactive and requires less milling. Furthermore, softer burned clinker is easier to grind. A 0.3% increase in average free lime results in a power saving of 3% to 4% in finish milling. Closer control of free lime with COSMA thus generates benefits in the form of lower energy costs to grind the clinker to the fineness required to meet specified strengths and setting times.


    Following is an estimate of the cost/benefit for 1,000,000tpa clinker plant, with grinding energy usage of 35kwh/tonne at $0.10/kwh, and in which average free lime increased from 0.7% to 1.2% through closer kiln control via COSMA. Cement price is $50 per tonne. (Take the conservative position that the 0.5% increase in average free lime will result in a 3% saving in grinding energy usage.)


    Fuel savings
    Current annual grinding energy costs = 1,000,000tpa * $3.50/tonne = $3,500,000
    Annual grinding energy saving @ 3% = $105,000


    Production increase
    Current annual plant revenue = 1,000,000tpa * $50/tonne = $50,000,000
    Annual production increase @ 3% = 30,000 tonnes
    Annual revenue increase @ $50 = $1,500,000


  3. Increased refractory life
    Kiln temperature and stability directly influence refractory life. Softer burning and a stable kiln will therefore extend refractory life. Closer kiln control with COSMA thus generates benefits in the form of lower refractory costs and longer periods between shutdowns.

  4. Reduced NOx emissions
    Softer burning at lower peak temperatures results in lower NOx emissions. Closer kiln control with COSMA generates benefits in the form of lower regulatory costs.

  5. Control of alternative fuels
    The use of multiple fuels, including alternative fuels, results in variable energy input to the kiln, depending on fuel quality and availability. COSMA will measure the resultant variations in free lime and the other clinker mineral phases, thus allowing the operator or expert system to compensate by controlling fuels or raw materials.

  6. Improved clinker management
    COSMA can analyse clinker at the point where it is separated on the basis of its free lime content and/or clinker type and directed to various applications or end uses. Thus, real time, continuous analysis by COSMA means that various clinker types are sent to the correct silo with minimal use of fringe bins.

  7. Improved clinker properties
    The production of better quality clinker through closer control of free lime and clinker mineralogy will allow the use of more additives in blended cements. The use of COSMA to improve clinker quality and thereby increases additives used means that either less clinker is used to produce the same amount of cement, or that more cement is sold by the plant.

  8. Less shift testing
    On-line instrumentation means that there is a lower requirement for laboratory analysis. COSMA can therefore enable the deployment of skilled staff to other tasks that improve the overall operation, uptime and reliability of the plant.