Picture of a Cement Vertical Raw Mill from a ZKG article
One month ago it was posted the question about “Who decides to stop the Raw Mill in a quality disturbance period?” in the LINKEDIN Group of Cement Industry Experts, (click here to go o the post) 14 comments were received but beyond the quantity, the quality of the comment was quite good, representative of the diverse operational cultures, representing experience from different perspectives in cement operation and staff, quite enriched outcomes by these contributions, a summary of the ideas and concepts has been documented, the following main ideas were identified:
- Responsibility to control the chemistry belongs to Quality Staff and/or Production Staff
- Responsibility to control the fineness belongs Production Staff
- The decision to stop shall be taken by Quality and/or Production Manager, few mentions of lab operator or production staff involvement in this issue.
- Beside previous point , there is a kind of consensus that the Quality and production management shall agree (formally or informally) on the criteria and conditions to stop the Raw Mill.
- The quality manager shall determine the specification for the chemical control of raw meal and production staff shall aim to accomplish the targets
- Explicitly or implicitly mention of Standard Operating procedures for Raw Mix Control, that includes criteria and guidelines.
- Is not just a matter of Quality Control but Quality Assurance
- More tools for predictability and prevention of quality deviations are required, now control is based on taking action after measuring deviations.
- Check the calibration of weigh feeders was mentioned
- It requires teamwork within Production and Quality staffs, not just department heads, to achieve effective decisions in this matter
Figure 1 Keywords of post comments
Figure 2 Same keywords but taking out the words.Quality, Production, Raw, Mill
Implicitly some type of management process was described in the experts contributions, where take the decision to stop the mill is only one of several coordinated actions those QC and production staff shall review on daily basis, but because the comments this process has several variations on specific issue like conditions to stop the mill, parameters to be considered to stop the mill, who decide, priority (production vs quality), etc.
What is missing in my consideration probably because the scope of the question shall be enhanced is:
- Automated systems that trigger control actions instead of the people or provide support the people in charge to take that decision
- Someone mentioned, preventive prediction tools to avoid to stop the mill or in the worst scenario, minimize stoppage time
- Participation of maintenance people to determine criteria and action in case of a mill stoppage is required
- Anticipation or alternative plans for to seasonal conditions (weather rainy or ice) or periodic failures (failures in handling materials of raw materials system)
- SOP for raw material contamination in bins of Feeding system
- Continuous review of weigh feeder calibration and control actions for frequent feeding failures (feeding disturbance)
This question posted in LINKEDIN just open a quite interesting conversation of recurrent opportunities of how tackle disturbances in the continuity during preparation of raw meal, one of these new conversations to explore is the use of technology to reduce the variability caused by natural causes of the raw meal preparation and also by special causes: it works? What technologies you know and have tested? Are sustainable? Have help to develop consistent and reproducible practices for control the chemistry of raw meal?
One last questions
- How is it possible to assess the cost-benefit ratio of possible solutions?
- Is technology a solution by itself of always a change in technology bring also a change in practices that need to be improved anyway?
- Is the process of actions coordination well established, well communicated? and agil?
- In that control process of raw meal chemistry, what is the effect of fuels composition and how fast you need to react to avoid problems with quality and operational issues?
Interesting, don’t you think?
Figure 3 The Macro System of Chemical Control of Raw Meal
In GAMONT we offer support to cash on this kind of opportunities, since how solve specific issues that affect process productivity, how redesign practices and coordination processes to make more effective the control, what technologies would help better than other to make this task more efficient in terms of reduce variability and how far the effectiveness of this system to control raw mix chemistry can reach considering not just the system by self but the whole production process, to determine the constraints that need to be solved to reach a higher level of improvement.
Have a nice day and lest talk soon!