Customer specs are getting tougher
Like in any industry, quality is of utmost importance in the cement industry. The quality consciousness has gone so far that the industry tries to ensure same consistency in each bag, let alone every kilogram of the product in it. That calls for consistency in mix of materials at various stages in their quality and characteristics. At this juncture, companies are adopting the latest laboratory instrumentation and automation techniques in the cement industry.
Cement plants are well spread out at their locations making it difficult for manually monitoring various parameters and adjusting process parameters on a real-time basis. Besides, availability of skilled manpower in remote areas where many cement plants are located, and retaining them has become a difficult task for companies. So, remote operation, support from distant locations, and online assistance are all vital for the smooth operation of quality control systems in modern cement plants.
Increasing environmental regulations, need for production efficiency and cost control at every level in a growing competitive business environment, need to curtail human errors in this continuous process industry, and growing demand for consistency of product quality by customers are placing increasingly tough requirements for sample analysis quality and complexity, and for sample throughput in cement plants, are some of the other reasons for cement companies adopting automation of their laboratory ecosystem.
In the early days, sample collection and transfer it to testing laboratory and adjusting the controls based on the laboratory results were being done manually. Then came semi-automatic sampling and automatic sample preparation; followed by automation of sample transportation; then a compact and interlaced design that suits a single integrated line or a clinker grinding facility was introduced, and now, robots have entered the arena. Today, human intervention in the process has been reduced to almost nil by robots.
Indian cement industry, known to be one of the leaders in energy efficiency and emission control in the world, is also emulating global best practices in quality control. The real-time evaluation of samples is a challenge with the size of plants, and any delay in corrective action could affect a large volume of production. Some of the challenges on the way include ensuring:
- High speed and accuracy of sample collection and results;
- Stricter quality controls sought by cement markets;
- Support for 24/7/365 operations; and
- Zero health and safety hazards or incidents.
Many of the cement manufacturing facilities are located at remote areas facing hostile environments or extreme weather conditions. Even equipment manufacturers are taking measures to meet these stringent demands. Dr Harald van Weeren, Global Manager for Cement Solutions and Hari Bhaskar, Manager for Automation Solutions, Malvern Panalytical, a division of Spectris Pte Ltd., say, "Our instruments are designed from the ground up with a hostile environment in mind. For instance, we have different product lines which are designed and calibrated for cement samples.
We understand that plants are dusty, humid and hot. Our Epsilon 4 benchtop XRF for elemental analysis and Aeris compact XRD are designed to be closed cabinet analysis to prevent dust from interfering with the sample analysis and also expensive detectors."
For 24/7 plant operation, the process laboratory must operate constantly with only very few, short stops, the laboratory automation system should be seamlessly integrated with the plant automation system and plant Management Information System (MIS) seamlessly. "With seamless integration...between Central Control Room (CCR) and Quality Control Lab, we've seen improved reliability. The integration between laboratory and plant automation which enabled us to get uniform quality of raw mix, stable operation with optimised oxygen control resulting increasing productivity and lower heat & power consumption," says Sanjay Joshi, Chief Manufacturing Officer, Nuvoco Vistas Corp.
"As far as integration to plant control, our automation control system can seamlessly communicate with plant control through commonly available protocols such as OPC Clients, Modbus or Profibus etc., which are used in cement industries. The laboratory analysis flow and equipment mimics can be displayed on Plant Control panels with alarm signals and other monitoring signals," say Harald and Hari.
Considering costs involved in manpower vs. automation, balance always tilts in favour of the latter and the industry is also moving towards the same. Some laboratories in the industry have also adopted robotic technologies. "The whole operation can be done with robots - with single/multiple robots," says Joshi.
Instruments like X-ray fluorescence and X-ray Diffractometer and optical microscopes are widely used cement industry laboratories.
Cement manufacturer, Nuvoco has procured X-Ray Fluorescence and X-Ray Diffraction equipment with reproducibility and high accuracy for its production units. "These equipments provide us with a much stricter control over our product's quality parameters. To reduce human errors, auto-samplers have been installed to draw a representative and average sample. Additionally, we have cross belt analysers installed for limestone quality assurance. Expert systems are installed for efficient control of the raw mix, clinker and cement quality," Joshi says.
Laboratory automation solutions company, Malvern Panalytical has designed cement editions to its product lines. Its newest range of X-ray diffraction diffractometers for understanding the mineralogy, is the Aeris compact XRD, which is the first benchtop XRD that is built with inputs from industry and users. "Unlike other solutions in the market, the Aeris is built with a closed box cabinet with external sample loading. This is so that cement dust does not get into the analytical chamber. Moreover, the Aeris is easy to operate, requiring minimal or no training. Plus it can handle numerous samples as customers have the option of placing it on the automation conveyor belt." One can choose the level of automation based on several factors like capacity of plant, integrated or grinding unit, technical skills and knowhow of plant personnel.
When the whole laboratory system and process is automated unbiased results can be viewed on the central screen without any manual intervention, and the same can be transmitted anywhere automatically, making multiple and remote observation of plant operations possible.
"Above all, companies gain in terms of data consistency and reliability. Automation eliminates manual sampling, where there could instances of operator biases. For instance, there may be variances or margin of error between operators. This is especially noticed when another operator takes on the next work shift,ö say Harald and Hari.
"Automated lab also reduces standard deviation of quality parameters in raw mix, thus resulting best utilisation of the different grade limestone (thus increasing mines life) and avoiding expensive purchased additives," says Joshi.
"So in a nutshell, it improves cement quality consistency, maximises plant availability and stabilises operation, improves raw mix uniformity and raw mix cost," adds Joshi.