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Stehlik P.,Brno University of Technology | Stehlik P.,EVECO Brno
Applied Thermal Engineering | Year: 2011

The present contribution shows certain practical aspects of selection and design of heat exchangers for industrial applications where polluted flue gas (off-gas) represents one process fluid. One of the key factors in designing heat exchangers for these applications is the primary selection of a suitable type. The presently available possibilities and methodologies of efficient heat exchanging device selection and supporting software do not allow covering all the needs of related industries. A concrete example of an industrial process furnace is used to demonstrate the issues of "compactness and enhancement vs. reliability" for various temperature levels of high temperature applications. Attention is also given to the specific area of fouling of the heat exchanging surfaces by flue gas. In high temperature applications, it is necessary to pay special attention to all phases of a solution. Heat integration of devices into the plant system and its possibilities are presented. The irreplaceable role of modelling and optimization on the design of heat exchangers and its design details is emphasized which may significantly contribute to final product quality. An important role in high temperature applications is also played by CFD simulations. © 2010 Elsevier Ltd. All rights reserved.


Dvorak R.,Brno University of Technology | Chlapek P.,Brno University of Technology | Jecha D.,Brno University of Technology | Puchyr R.,EVECO Brno | Stehlik P.,Brno University of Technology
Journal of Cleaner Production | Year: 2010

Meeting environmental limits represents the most important issue in the field of waste processing. Our primary effort consists either in eliminating hazardous emissions or in prevention of their production. However, this is not feasible in most cases therefore the so called secondary methods have to be applied. Technologies based on adsorption of hazardous compounds using activated carbon, deNOx/deDiox technologies as well as technology of catalytic filtration using a special material REMEDIA® proved itself to be very efficient. The latter technology consists in using a baghouse with bags manufactured from a special material (two layers - membrane from ePTFE and felt with bound in catalyst) called REMEDIA® which has successfully been used for removal of PCDD/F during recent period. However, it has been found that this technology can partially remove NOx as well. Based on our experience from operation industrial incineration plants it has been proved that even after more than three years' operation the activity of filtration material was not decreased and efficiency of dioxins removal from flue gas ranges from 97 to 99% (Pařízek et al., 2008). Based on industrial experience and new findings it has been decided to focus continuing research and development on deNOx experiments by applying SCR using the above mentioned efficient filtration material. This type of material is primarily designed for reduction of PMs and PCDD/F. Experiments with this filtration material should test possibilities for simultaneous reduction of PMs, PCDD/F and NOx. Tests are performed in MSW incineration plant utilizing new experimental unit and under standard conditions. Waste processing capacity of the incineration plant amounts to 15 t/h. Tests result in evaluation of overall reduction efficiency and negative factors that might influence the efficiency. Catalytic filtration is further compared to other types of deNOx methods. Thus we have obtained qualitatively new knowledge about this method the value of which is emphasized by full scale industrial testing. © 2010 Elsevier Ltd. All rights reserved.


Pavlas M.,Brno University of Technology | Stehlik P.,Brno University of Technology | Oral J.,EVECO Brno | Klemes J.,University of Manchester | And 2 more authors.
Applied Thermal Engineering | Year: 2010

The main part of this paper is an industrial case study. It deals with an application of a heat pump in energy systems for biomass gasification in a wood processing plant. Process integration methodology is applied to deal with complex design interactions as many streams requiring heating and cooling are involved in the energy recovery. A refrigeration cycle maintains low temperature in the scrubber where the production gas (or synthesis gas-syngas) is cooled and undesirable contaminants are removed before the syngas is introduced into the engine. In addition to electricity generation, a large amount of waste heat is available in the biomass gasification system studied in the paper, and its appropriate heat integration with utility systems within a plant allows the available heat to be efficiently utilized for the site. The conceptual understanding gained from the case study provides systematic design guidelines for further process development and industrial implementation in practice. © 2009 Elsevier Ltd. All rights reserved.


Stehlik P.,Brno University of Technology | Stehlik P.,EVECO Brno | Turek V.,Brno University of Technology | Jegla Z.,Brno University of Technology | Kilkovsky B.,Brno University of Technology
Proceedings of the 15th International Heat Transfer Conference, IHTC 2014 | Year: 2014

A long-term experience and know-how from waste processing and especially from waste- and biomass-toenergy systems as well as continuing research and development brings new insights into manufacturing of equipment and their operation. Polluted flue gas (off-gas) causes high propensity to fouling and necessitates of subsequent cleaning. In some cases, it is not possible to utilize conventional approach. Novel designs of air pre-heaters, heat recovery steam generators and special heat exchangers therefore always respect primary importance of processes themselves as well as analyses aimed at selection and design of heat exchangers including specific features and fouling problems. However, the problems in operation cannot be avoided and therefore it is often necessary to use tailor-made solutions making provisions especially for fouling. We have been utilizing very efficient approach combining intuitive design and sophisticated tools based on Computational Fluid Dynamics (CFD). It is used for both troubleshooting and virtual prototyping and illustrated through industrial applications. Based on solving concrete industrial examples, a useful methodology which generalizes several particular features and takes into account economic aspects of different cases has been developed.


Ucekaj V.,EVECO Brno | Sarlej M.,EVECO Brno | Puchyr R.,EVECO Brno | Oral J.,EVECO Brno | Stehlik P.,Brno University of Technology
Clean Technologies and Environmental Policy | Year: 2010

Maximum possible utilization of renewable sources as well as minimization of waste production and preference of recycling is definitely a positive trend. Global economic crisis, however, has brought about several aspects that have been neglected before. It is difficult to find a market for much of the sorted PET bottles and paper; thus sorting itself and recycling unfortunately lose their meaning. This gives rise to the question as to whether current procedures and technologies are appropriate or not. This article tries to offer a new approach which lies in maximizing waste processing (sorting, recycling, incineration, etc.) at the site of its production, along with an emphasis on maximizing efficiency of waste treatment by minimization of transport distances, labour costs and use of synergic effects of several different technologies in an open central controlled system called "MICROREGION". © Springer-Verlag 2010.

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