Case Studies
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Implementation of CEMTEC’s Online Particle Size Analyzer into CEMEX‘ Rudniki plant
The Cemex Rudniki plant is located in Poland, approximately 74 km north of the regional capital Katowice. With five cement mills in operation, the plant has a maximum annual production capacity of 1.2 Mt cement. The cement type CEM III A 42.5 with its high slag content is accounts for the largest proportion of the overall production. In 2016, CEMEX acquired a Cemtec Particle Size Analyzer (CEOPS) with a multi-pattern controller for process optimization, which has proven crucial for product quality improvement and operation upgrade.
Challenge
- Correlating the fineness of cement with its comprehensive strength during implementation of the controller
- Persuade the operational staff to the new system, which aims for P80 instead of Blaine as the main quality parameter
Solution
- Commissioning of a controller, the CEOPS analyzer, a compressed air maintenance unit and four sampling units
- Reconfiguring the automation system by replacing the Blaine value with the P80 value as a reference for cement production.
Result
- Increased total plant capacity
- Reduced specific energy consumption
- Improved cement quality due to continuous feedback from the CEOPS analyzer
- Reduced operational risk
- Decreased workload of laboratory staff
CEOPS Analyzer
The CEOPS is a customized solution, which provides online measurement of the particle size distributions. It is entirely developed and manufactured by CEMTEC in Europe. This tailored approach guarantees representative sampling required for proper regulation of the plant. There are multiple communication interfaces to integrate the CEOPS unit into higher-level control systems, offering various options for improved control of grinding circuits. For the measurement, a Malvern Insitec laser unit is incorporated into the CEOPS system.
Controller
The CEOPS was connected with a multi-pattern controller to optimize the grinding parameters of the cement mills. In this application, the basic operational principle can be described as follows: The controller gathers information from the plants’ main PLC (grinding chamber filling degree, operational set points) and the CEOPS (fineness of the product), generating optimized set points for the fresh feed and the dynamic separator based on this data.
Project description
The described system was delivered and subsequently commissioned in the second quarter of 2017. The scope of delivery comprised a controller, the CEOPS analyzer, a compressed air maintenance unit and four sampling units. All sampling units were assembled in pre-selected positions to cover all production lines. Figure 1 and 2 visualize the positions and the sampling units’ set-up in the plant. During the implementation of the controller, correlating the fineness of the cement with the compressive strength proved to be one of the most difficult tasks.
Therefore, 431 different samples for each cement type were collected in a test trial, in which the most characteristic values, namely the Blaine value, the P80 value as well as the 2-day and 28-day compressive strength, were determined and combined in a data set. The operational data and the values obtained by the laboratory were analyzed regarding their interrelationship. While the gathered data displayed a poor correlation between the measured Blaine values and the compressive strength, it turned out that the P80 can be easily correlated to the compressive strength. Figures 3 and 4 illustrate the improvement in quality resulting from the implementation of the CEOPS system, as the standard deviations of the main cement quality parameters - the 2-day and 28-day compressive strength - has decreased. When implementing the algorithms for the controller feature, it turned out that the product’s P80 value is more reliable for the adjustment of the plant‘s set points, because the measurement is independent of the laboratory staff, while the Blaine measurement method relies on manual operation
Product Description
Figure 5 highlights the high deviation in Blaine value while keeping the P80 constant. Considering the points mentioned above, CEMEX decided to change its control philosophy and replaced the Blaine value with the P80 value as a reference for cement production. After the reconfiguration of the automation system, CEMEX was able to achieve a higher throughput while improving the quality of its products. The biggest challenge hereby was to convince the operational staff to adapt to and familiarize themselves with the new system, which aims for P80 as the main quality parameter rather than for the Blaine value.
| P80 (Mm) | 24 | 25 | 26 | 27 |
|---|---|---|---|---|
| Average value (Blaine) | 4568 | 4574 | 4780 | 4376 |
| Standard deviation | 186 | 223 | 373 | 263 |
| Cement type | Difference in energy consumption with regulation ON-OFF(%) |
|---|---|
| CEM | 42.4R | 103.1 |
| CEM | 52.2N | 95.4 |
| CEM || BM(V-LL) 32.5R | 100.5 |
| CEM || BS 42.5R | 100.0 |
| CEM || B-V 32.5R | 108.2 |
| CEM || A 42.5N | 86.8 |
Promising Results.
More than two years have passed since the tailormade system was implemented in the CEMEX Rudniki plant, having brought considerable benefits ever since. A comparison of the collected production data shows that 5% of energy was saved as a result of the implementation of the CEOPS system.
Table 1 visualizes the economic improvement. The calculations were performed based on more than 25 thousand data points, which have been collected during the test trials. The values presented in Table 1 refer to the drawn power of the entire grinding circuit and the total amount of produced cement.
Despite this achievement, the total cost of maintaining the system merely amounted to less than 2,500 €/year. Furthermore, the availability of the system was estimated at 98%, as the majority of the system’s shutdowns only occurred during scheduled standstills of the plant. Therefore, the initial investment for purchasing and installing the system was amortized in less than a year. The surplus energy from the optimized production process was utilized to increase the capacity of the grinding facility. Additionally, the cement quality has improved, which is a major asset for CEMEX, as the company is widely known for its high standards in terms of product quality.
The CEOPS system CEMEX purchased for its Rudniki plant led to highly positive results, making the project a great success.