The future of ceramic kilns: EU recognition for the DREAM project led by Sacmi Forni

The European Commission lists the project - completed successfully in September 2019 - as one of the co-funded 'success stories' of the Horizon 2020 programme. The outcome? A predictive model to accelerate innovation, with net consumption savings, higher efficiency and reduced emissions.
To build higher-performing ceramic kilns that consume and pollute less: this was the goal of the DREAM (Design for Resource and Energy efficiency in ceramic kilns) project, co-funded by the EU and led by SACMI Forni and CRIT (Centro di ricerca e innovazione tecnologica) based in Vignola.  
Completed in 2019, the project is now one of the 'success stories' showcased on the EU Commission website in recognition of the intense research and development work carried out by the two project leaders together with 11 other European partners from the university, industrial and research worlds.

The software

At the heart of the DREAM project lay the development of a computerised kiln model where all the key stages of the process – infeed, pre-heat, firing, indirect cooling and final cooling – are sub-divided into discrete moments and analysed using equation systems with high predictive power. The result? Extremely useful, measurable data on the anticipated results and a model useful for accelerating innovation.

The software

The micro-turbine option

«To produce all the electricity needed without going beyond the factory’s requirements», explains Gabriele Frignani of SACMI Forni, is central to the proposal, which tested the feasibility of powering the kilns with micro-turbines in place of traditional large-scale turbines.
The first advantage is strictly economical - the excess energy produced by large-scale turbines is usually sold back to the mains grid and thus taxed – but there is also the second advantage that the plant flows are simplified and it is possible to set up the machine to self-produce the exact amount of energy needed to power the electrical and thermal systems.  
By way of example; if we consider the installation of a micro-turbine on an existing kiln (the DREAM project tested a solution with 100 kW/h power output), the energy saving achieved running the kiln is equal to 100% of the electrical energy produced, net of the costs of the burnt gas (in Italy the cost differential between gas and electricity is approx. a fifth with the same kW produced).
The third advantage is more efficient handling of any power blackouts. In fact, with this system, the kiln does not have to be re-started so it is possible to avoid the usual procedures for cleaning out the systems which can take up to 10 minutes causing rejects and production downtime.

Better utilization of excess kiln heat

One of the advantages of the predictive model is that it allows the effectiveness of specific changes to kiln design to be tested in advance.  For example: the idea of directing hot fumes towards parts of the kiln itself may prove to be less effective than sending this heat to the upstream dryer or other machines which use the heat as primary energy source.
«On the basis of the theoretical model and tests carried out, maximum savings are obtained when the heat is directed towards, for example, the spray-dryer (numerically speaking the heat associated with the micro-turbine fumes reduces the energy consumption of the spray-dryer)

Better utilization of excess kiln heat
It is also relatively cost-effective to direct the fumes to the recovery driers, whereas the field-tested solution to direct the heat to the recirculation driers has been shown to be only partially efficient», Gabriele Frignani tells us.
The results are further savings thanks to a more efficient use of the thermal energy of the burnt fumes.

Reduced waste and emission

By definition, every industrial kiln releases a certain quantity of heat into the atmosphere. Part of the DREAM project concerned the development and testing of a new generation of kiln linings (new paints and refractory materials) that reduce this heat loss by approx. 10 percentage points.
Furthermore the new coating introduced - «a completely new product on the market which has now become an integral part of SACMI Forni’s range of products» - has shown unprecedented resistance to chemical aggression,  increasing the lifetime of the linings and reducing maintenance costs.  
At factory level, the use of these new systems can show a drop in thermal energy consumption of more than 5% (considering an annual consumption of 5 million cubic metres of gas, or its electrical energy equivalent, a net saving of approx.. 500 tons in CO2 emissions could be obtained). 
In all cases, the thermal and electrical energy savings obtained from gas combustion give a net reduction in carbon dioxide emissions in the proportion of 2 kg of CO2 for each m3 of burnt gas (or equivalent in electrical energy).

Production voids

The DREAM project has also produced some important innovations in the management of “production voids”. Whereas the traditional approach is to deal with the problem locally by applying “void recipes” in the kiln, DREAM designed software to identify the production void as soon as it forms in line and, through its supervisor, it enables the kiln to “prepare” the optimum thermal conditions for the arrival of the void. «Basically the model can foresee the arrival of production voids generated by the various machines which make up the line and therefore assess any corrective actions to be taken on the kiln in good time and through the use of objective parameters».

The future

The project also tested both a new monitoring software and the development of a new generation of “multi-use” filters capable of significantly lowering even emissions like NOx without having to first lower the temperature of the fumes before filtering.  This heralds what will, in all probability, become a necessity for ceramic plants after 2023 when new EU regulations (BREF) on industrial emissions limits will be published.
«At the moment this new generation of filters are at the Research and Development stage. We believe that this issue will form an important part of the future for our industrial plants, especially if new regulations require further lowering of limits for nitrogen oxide emissions».

The future

Limits of the virtual model

«Increased levels of knowledge in areas that might be decisive in keeping ahead of market developments, standards and consumption patterns - underlines Gabriele Frignani - have been a pivotal part of the DREAM project, as have the opportunities that stem from working with international and multidisciplinary teams at the very highest level». Without support from Europe, these research activities would have been beyond the reach of the single companies «but the market demands continuous innovation in real time».
Of course – points out Frignani – even the virtual model has its limits. For example «it cannot predict any defects in material following a variation of process parameters, but it can nevertheless indicate the best thermo-dynamic conditions». This is why «industrial tests carried out inside the factory remain necessary in order to apply the virtual model to a real kiln which is already up and running».
In short, SACMI Forni takes an approach that seeks to generate added value. As well as incorporating some of the innovations developed during the DREAM project into its new product range, SACMI Forni works alongside customers daily to perform in-field testing of this new approach to kiln engineering/control and so improve sustainability, competitiveness and efficiency.
Find more information also on the European Commission website (General Directorate for Research and Innovation)

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