Automation to maximise product quality

May 2, 2017 Mette Dobel

FLSmidth’s newest QCX/BlendExpert™ system improves cement quality significantly.

Tarja Miettinen, Quality Engineer for Finnsementti, using the new QCX/BlendExpertTM  V8 system

For 40 years, FLSmidth has been a pioneer in advanced control systems for cement applications. The QCX/BlendExpertTM range of applications support product optimisation from quarry to cement. It is an advanced control system that controls raw material feeders, additives and silo content to ensure steady quality, thereby reducing fuel consumption and improving productivity. Through advanced estimations it eliminates the need for manual sampling and analysis of raw material and additives, overall resulting in increased stability and profitability.

The eighth generation
The most recent generation of the software is based on vast experience from more than 700 installations of quality control (QCX) systems. It has been designed by FLSmidth’s team of quality experts using the latest control technologies, which, together with today’s powerful PC processors, enable very complex process simulations and corresponding estimations.

The QCX/BlendExpert V8 system was tested on Finsementi’s Lappeenranta plant in Finland, achieving impressive results. Despite previous generations of the application performing very well, the new software has resulted in a 50 percent reduction of Lime Saturation Factor (LSF) standard deviation compared with the QCX/BlendExpert™ V7 systems. Tarja Miettinen, Quality Engineer for Finnsementti describes the immediate impact of the system:

“When the team turned on the new V8 system, it immediately became clear that this was a very good system.”

“We have experienced excellent service from FLSmidth during this period – always receiving fast replies and very competent assistance from people who know the issues in a cement process,” she says, about the end-to-end implementation process and the collaboration with FLSmidth.

Mette Dobel, Global Product Line Manager – Quality Control at FLSmidth, has been responsible for overseeing the development of the new QCX/BlendExpert system. She describes this latest version of the system as a major rethink:

“Because we can make use of more powerful computing power, we can create very advanced process models. Add to this our deep understanding of cement production processes and we were able to build a smarter system.”

"Raw meal quality is becoming increasingly more important, particularly as there is more focus on special cements" - Mette Dobel, Global Product Line Manager - Quality Control at FLSmidth

Strict quality control
In order for cement plants to achieve the best return on investment and to ensure that the cement quality is kept consistent, it is crucial to have very strict quality control procedures in place. Advanced quality control systems are essential in minimising variability in material composition throughout the cement manufacturing process by controlling all chemical compositions. To make these systems successful, they require fast and accurate sampling of
process streams as well as a well-working laboratory.

The QCX/BlendExpert system can operate with laboratory XRF results only, or in a combination of laboratory XRF and online analyses incorporating all results in the control algorithms. The single loop control ensures optimal control as it combines seamlessly the high accuracy of the laboratory XRF instrument with the speed of the online analyzer results.

According to Mette Dobel, quality is becoming more important, particularly as there is more focus on cost of production and on special cements:

“The new QCX/BlendExpertTM system offers cement producers an important step up in quality control.” - Mette Dobel, Global Product Line Manager – Quality Control at FLSmidth

Further to improved quality control, the new QCX/BlendExpert V8 system provides a long list of benefits and helps to overcome some significant challenges in cement production.

Improved features give clear benefits
The new, intuitive user interface, provides an easy overview of the next control steps. The advantage is that this includes and thereby improves understanding of the automated system's next action by plant operators.

Automatic feeder control
The online accounting of individual raw material feed streams and other relevant materials, such as dust, coal, ash, fly ash, alkali and bypass, is based on signals from the weigh feeders.

QCX/BlendExpert software ensures automatic correction of feeders. Thus, if a feeder has been incorrectly calibrated, or not calibrated at all, the QCX/BlendExpert system will detect the error and correct the feeder set-point to offset it. This unique feature contributes to improved overall chemical control performance.

If a feeder is in starvation, the QCX/BlendExpert software estimates whether it can still reach its target in this condition. If it cannot reach all targets, it will, according to control philosophy, jeopardise the targets, which which are least important to the overall clinker quality, for example, alumina module (AlM).

In order to meet the demands of modern plant conditions, where material types can rapidly change, QCX/BlendExpert software can operate with multiple materials per feeder. This results in a fast, flexible and responsive system, with minimal operator intervention, when faced with varying material types.

Maximum use of alternative fuels
Alternative fuels are becoming important for most cement plants. Using by-products provides waste management options that can be economically viable, regionally available and environmentally sound. Some alternative fuels generate chemical constituents, such as alkalis or chlorides that must be considered in the equations when designing the chemical targets of the cement. QCX/BlendExpert system is designed to handle these important factors.

Results from Finnsementti Lappeenranta plant in Finland. The 2011 values represent operation with QCX/Autosampling™ and QCX/BlendExpert™ system V7. The 2015 values represent operation with QCX/Autosampling and QCX/BlendExpert V7 and a PGNAA (prompt gamma neutron activation analysis) before the raw mill. The 2016 values represent operation with QCX/Autosampling and a PGNAA before the raw mill and QCX/BlendExpert V8. Considerable improvements were achieved with the new QCX software.

Advanced modelling enables ‘dynamic bias compensation’ of installed online analysers to compare and adjust the online analysis to the correct laboratory analysis. This makes it more accurate and better for control.

One of the reasons the QCX/BlendExpert system has achieved excellent results is due to its innovative way of dealing with silo content. Silo content and composition is estimated in accordance with applied silo models (continuous, layered or batch) and current product type.

This gives a very efficient and effective chemical process model where chemistry is constantly tracked, also if the mill is stopped and additives are still added to the silo.

The QCX/BlendExpert software's raw material estimation provides a reliable assessment of what chemistry is available in the feeders at any given time, saving both time and money as it eliminates the need for physical sampling, sample preparation and analysis of raw materials – a labour-intensive job.

Using the control tuning feature, the operator can experiment with the blending circuit chemistry by changing feeder settings, material qualities and set points as well as other variations, and subsequently examine the final chemistry with these parameters present. In this advanced feature, it is also possible to call up historical settings and results in order to investigate various scenarios around these events This allows operators to plan for chemical variations from the quarry or from alternative raw material suppliers and evaluate if such materials are acceptable and within control targets.

Rapid financial return
The QCX/BlendExpert V8 system allows fast payback on investment. This is due to not only lower fuel consumption in the kiln and preheater, reduced equipment wear and longer lifetime of mechanical parts, but also optimal use of raw materials and additives.

Automation for better quality
Optimising quality control starts with automated accurate sampling, sample preparation and X-ray analysis, which ensures fast, correct chemical breakdown. Reliable chemistry inputs are the basis of any well-functioning advanced control system.

The fast and complex calculations, which take chemistry, tonnages, price and other factors into the equation, enable the QCX/BlendExpert system to adjust the feeders more frequently and reliably than any human operator can.

Mette Dobel concludes: “We are always striving to automate and optimise control of cement plants and by combining process knowhow, the latest control technologies and today’s powerful PC processors, we have achieved best-in-class performance with our QCX/BlendExpert V8 system.”

Mette Dobel

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