Theses of the PhD dissertation

Átírás

1 Theses of the PhD dissertation PRODUCTION OF MODERN FUEL COMPONENTS FROM FISCHER-TROPSCH HEAVY PARAFFIN MIXTURE Doctoral School of Chemical Engineering and Material Science, University of Pannonia Made by: GYÖRGY PÖLCZMANN chemical engineer, MSc. Supervisor: DR. JENŐ HANCSÓK chemical engineer, Eur. Ing., DSc. professor University of Pannonia Faculty of Engineering Institute of Chemical and Process Engineering MOL Department of Hydrocarbon and Coal Processing 2013

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3 1. INTRODUCTION AND OBJECTIVES Nowadays, the application of fuels and lubricants produced from renewable feedstocks has come to the front because of serious environmental problems (e.g. greenhouse effect) and the ambiguity of crude oil supply (e.g. import dependence). In the integrated Fischer-Tropsch synthesis liquid hydrocarbon product mixtures with different composition ( synthetic crude ) and subsequently fuels, base oils, paraffins and other special products are produced from natural gas, coal, crude oil residues, biomass and wastes through synthesis gas in three main steps. The Fischer-Tropsch wax (>30% of the Fischer-Tropsch products) produced of synthesis gas of different sources is a mixture of high molecular weight (C 20 -C 100 ) n-paraffins, which is practically free of sulphur, nitrogen and aromatics, but which is a solid at ambient conditions (high pour point, C). The Fischer-Tropsch paraffin mixture can be upgraded by hydrocracking or hydroisomerization to get lower pour point product. The product comprises of lower chain and/or branched hydrocarbons. The volume of the gaseous and low octane number naphta products formed over conventional hydrocracking catalysts is significant (6-8% and 10-20%), however, the selectivity for target products (gas oil, base oil) is relatively low. Therefore, it is very important to develop new catalytic systems (reactor, catalyst, reaction mixture, process parameters) for the production of the appropriate mixture of gas and base oils (target products) with high isoparaffin content, and mainly to develop the suitable catalysts and determine the application parameters. The general main objective of my research and development work was to contribute to the economic and effective production of high quality products (gas oil and base oil) from biomass based heavy paraffin mixture produced by Fischer-Tropsch synthesis with isomerization hydrocracking. The experiments were made on bifunctional catalysts with different composition and in a catalytic system containing two catalyst with main function. For the better understanding of the catalytic reactions, experiments were made with n-hexadecane model compound on these catalysts. Correlations were made between the properties of the catalysts, the applied process parameter combinations and the quality properties of the feedstocks and the products. The advantageous catalyst were investigated in a catalytic system together with a commercial hydrotreating catalyst to produce base oil product with high oxidation stability. Based on the application properties of the best quality products recommendations were made how to apply these products. 3

4 2. EXPERIMENTAL Part of the experiments (investigations in microreactor) were made in a high-pressure microreactor system which was accessible by the MTA Chemical Research Center in the frame of a scientific co-operation. The experiments with increased volume were carried out in a high-pressure reactor system. This consists of a tubular down-flow reactor of 100 cm 3 efficient volume and it is free of back-mixing. The system contains all the equipments and devices applied in the reactor system of industrial hydrotreating plants (pumps, separators, heat exchangers, as well as temperature, pressure and gas flow regulators). The feedstocks of the experiments were Fischer-Tropsch paraffin mixture produced from biomass based synthesis gas, and n-hexadecane as model compound. The tested catalysts were produced in the frame of a co-operation with the MTA Chemical Research Center, or they were base catalyst available in commercial operation. Whenever it was possible, the required analytical methods of the actual standards were used. Furthermore other physico-chemical and spectroscopical methods were used, mainly during the investigations of the catalysts. The experiments were carried out on a catalyst by steady-state activity and continuous operation. 4

5 3. NEW SCIENTIFIC RESULTS 3.1. Investigation of different catalysts for the hydroisomerization of n-hexadecane model compound [4] It was concluded that the bifunctional Pt/AlSBA-15 catalyst (weak acidity, organized nanopores) had higher selectivity for the hydroisomerization of n-c 16 hydrocarbon, than the strong Brønsted acidic Pt/beta or the barely acidic Pt/SAPO It was pointed out that from the view of the formation of dibranched C 16 compounds the mesoporous Pt/AlSBA-15 catalyst was more effective than the microporous, strongly acidic Pt/beta. The main reason behind the differences of i-c 16 selectivities was rather the different cracking activity than the different pore structure It was concluded, that C above the temperature belonging to the starting activity of the catalysts mono- and dibranched C 16 isomers were in the product mixtures. At higher temperatures the iso-c 16 yield began to decrease, mono- and dibranched cracking products appeared too Investigation of isomerization and hydrocracking of biomass based Fischer- Tropsch heavy paraffin mixture to produce gas oil and base oil fraction; comparison of micro- and mesoporous catalysts [1-3,5-6,8,10]. To reach the desired objective it is elemental to find the proper ratio of isomerization and cracking reactions and to adjust it to the maximal yield and the deisred properties of the desired product fraction. The main tool for this purpose is the formation and choosing of the catalyst with proper acidity and bifuncionality It was concluded that the investigated Pt/SAPO-11 is applicable to produce base oil fraction with high isoparaffin content from Fischer-Tropsch heavy paraffin mixture It was recognized that the isomerizaton and hydrocracking of Fischer-Tropsch heavy paraffin mixture can be a new application area of the Pt/AlSBA-15 catalyst, which was not investigated for this purpose in detail It was concluded that from the different platinum containing AlSBA-15 supported catalysts the one having 0,5% platinum was the most applicable for the production of

6 target product with high isoparaffin content and with adequate yield. Higher platinum content practically do not result significant activity increase even in case of longer experiments (240 hours) On the Pt/AlSBA-15 catalyst the advantageous process parameter combinations (P=40-60 bar, T= C, LHSV=0,5-1,5 h -1, illetőleg T= C, P=50-60 bar, LHSV=1,5-2,0 h -1 ) of the production of the target products with high isoparaffin content [C 11 -C 20 (62,1-80,2%) and C 21 -C 30 fraction (52,4-54,5%)] and with adequate yield (>25% and >50%) were determined It was recognized that the advantageous process parameter combinations for the two target fractions with high isoparaffin content are not in the same range. That means the flexible changing of the process parameters the desired fraction can be produced with high yield, subject to the demands It was concluded that the experiments with n-c 16 model compound confirmed the main conclusions of the experiments made with F-T heavy paraffins Simultaneous application of 0,5% Pt/AlSBA-15 catalyst and a commercial hydrotreating catalyst (in one reactor bed in laboratory equipment) to produce high stability base oil fraction [7,9] It was proved that the increased size catalytic system has high flexibility too, because expediently changing the process parameters one or another target product can be produced with high yield and high isoparaffin content It was concluded that the increased size catalytic system with two catalyst is applicable to produce high stability base oil products, simultaneously with the production of high quality gas oil products The advantageous process parameters of the production of target products with high isoparaffin content were determined The products had practically zero sulphur-, nitrogen- and aromatic content (<5-5 mg/kg and <0,1%) already at the mildest process parameter combinations. This can be explained with the practical total sulphur- nitrogen- and aromatic removal in the investigated new catalytic system. 6

7 4. PUBLICATIONS IN THE TOPIC OF THE PHD DISSERTATION 4.1. Base publications of the PhD dissertation 1 Pölczmann, Gy., Szegedi, Á., Valyon, J., Wollmann, A., Hancsók, J.: Catalytic Conversion of Fischer-Tropsch Waxes, Chemical Engineering Transactions, 2010, 21, Gy. Pölczmann, J. Valyon, Á. Szegedi, R. M. Mihályi, J. Hancsók: Hydroisomerization of Fischer Tropsch Wax on Pt/AlSBA-15 and Pt/SAPO-11 Catalysts, Topics in Catalysis, 2011, 54 (14-16), , ISSN: , DOI /s (Impact factor: 2,624) 3 Pölczmann, Gy., Valyon, J., Hancsók, J.: Investigation of Catalytic Conversion of Fischer-Tropsch Wax ont Pt/AlSBA-15 and Pt/beta Zeolite Catalysts, Hungarian Journal of Industrial Chemistry, 2011, 39 (3), Valyon, J., Pölczmann, Gy., Kollár, M., Hancsók, J.: Pore size and acidity effects on the catalytic activity in the hydroisomerization and hydrocracking of Fischer-Tropsch wax, Topics in Chemistry and Material Science, 2011, 6., Pölczmann, Gy., Valyon, J., Mihályi R. M., Hancsók, J.: Selective isomerization of Fischer-Tropsch paraffin mixture on Pt/AlSBA-15 catalyst, Interfaces 11, Sopron, szeptember , CD Proceedings, ISBN: , 13 pp. 6 Pölczmann, Gy., Valyon, J., Hancsók, J.: Catalytic conversion of Fischer- Tropsch wax on Pt/AlSBA-15 and Pt/β zeolite catalysts, XIX International Conference on Chemical Reactors, CHEMREACTOR-19, Austria, Wien, szeptember 5-9., Abstracts CD PP-III Pölczmann, Gy., Hancsók, J.: Production of high stability base oil from Fischer-Tropsch wax, 18th International Colloquium Tribology, Stuttgart/Ostfildern, Germany, január In Book of Synopsis 71. (ISBN: ), In CD Proceedings 10 pp. ( ) 8 Pölczmann, Gy., Valyon, J., Mihályi R. M., Kollár M., Eller Z., Hancsók, J.: Investigation of isomerization and hydrocracking of Fischer-Tropsch wax on Pt/AlSBA-15 and Pt/MCM-22 catalysts, 5th FEZA Conference, Spain, Valencia, július 3-7., Abstracts (ISBN: ) PE-P- 022, Pölczmann, Gy., Hancsók, J.: Nagy stabilitású alapolaj előállítása Fischer- Tropsch paraffinelegyből, Műszaki Kémiai Napok 12, Conference Proceedings, ISBN: , 2012, Pölczmann, Gy., Valyon, J., Hancsók, J.: "Fischer-Tropsch paraffinok katalitikus átalakíthatóságának vizsgálata Pt/AlSBA-15 és Pt/β zeolit katalizátorokon", Műszaki Kémiai Napok 11, Conference Proceedings, ISBN: , 2011, Publications concerning the topic of the PhD dissertation 11 Pölczmann, Gy., Hancsók, J.: Investigation of catalytic production of modern base oils and fuels, 17th International Colloquium Tribology, Stuttgart/Ostfildern, január , In Book of Synopsis 83., In Proceedings 7 pp 12 Pölczmann, Gy., Valyon, J., Szegedi, Á., Hancsók, J.: Investigation of selective isomerization of Fischer-Tropsch wax, 16th International Zeolite 7

8 Conference - 7th International Mesostructured Materials Symposium, Extended Abstracts -CD, július Pölczmann, Gy., Szegedi, Á., Valyon, J., Wollmann, A., Hancsók, J.: Catalytic Conversion of Fischer-Tropsch Waxes, 13th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, Bohemia, Prague, augusztus 28. szeptember 1., In CD Proceedings (ISBN ), 6 oldal 14 Pölczmann Gy., Valyon J., Mihályi R. Magdolna, Hancsók J.: "Investigation of isomerization and hydrocracking of Fischer-Tropsch wax on different catalysts", SynFuel2012 Symposium, Munich, június ; in Proceedings P227, 2 oldal (extended abstract) 15 Pölczmann, Gy., Valyon, J., Hancsók, J.: "Nagy molekulatömegű Fischer- Tropsch paraffinok átalakíthatóságának vizsgálata", Műszaki Kémiai Napok 10, Conference Proceedings, ISBN: , 2010, Hancsók., J.; Varga Z.; Eller., Z.; Pölczmann, Gy., Kasza., T.: "Liquid Alternative Diesel Fuels with High Hydrogen Content", 9th International Colloquium Fuels, január , Stuttgart/Ostfildern, Germany, ISBN-Nr , Pölczmann, Gy., Baladincz, J., Hancsók, J.: Investigation Of Producing Modern Base Oils, Hungarian Journal of Industrial Chemistry, 2008, 36 (1-2), Pölczmann, Gy., Baladincz, J., Nemesnyik, Á., Hancsók, J.: Környezetbarát motorolajok IV. Újgenerációs szintetikus alapolajok és a növényolajok, Magyar Kémikusok Lapja, 2007, 62(3), Hancsók, J., Krár, M., Pölczmann Gy., Holló, A.: A bioeredetű motorhajtóanyag gyártás új lehetőségei, I. Bio-szintézisgáz előállítása, Olaj Szappan Kozmetika, 2006, 55(4), Baladincz J., Pölczmann Gy., Magyar Sz., Hancsók J.: Az izoparaffinok jelentősége a kőolajiparban VI. Nagy viszkozitásindexű alapolajok előállítása szintézisgázból, MOL Szakmai Tudományos Közlöny, 2007, 1, Hancsók, J., Krár, M., Pölczmann Gy., Holló, A.: A bioeredetű motorhajtóanyag gyártás új lehetőségei, Szintetikus biogázolajok II. szintetikus biogázolaj előállítása bio-szintézisgázból, Olaj Szappan Kozmetika, 2007, 56(1), Pölczmann Gy., Hancsók J., Varga Z., Nagy G.: Gázolajok előállítása szintetikus kőolaj izomerizáló hidrokrakkolásával, Műszaki Kémiai Napok 06 - Conference Proceedings (ISBN ), 2006, Pölczmann Gy., Magyar Sz., Hancsók J.: Korszerű szintetikus alapolajok előállítása biomassza alapon, Műszaki Kémiai Napok 07 Conference Proceedings (ISBN ), 2007, Nagy, G., Pölczmann, Gy., Varga, Z., Hancsók, J.: Gázolajpárlatok aromástartalmának csökkentési lehetőségei I., MOL Szakmai Tudományos Közlemények, 2007, 1, Nagy, G., Hancsók, J., Varga, Z., Pölczmann, Gy., Kalló, D.: Hydrodearomatization of Gas Oil Fractions on Pt-Pd/USY Catalyst, Petroleum & Coal, 2007, 49(1), Nagy, G., Hancsók, J., Varga, Z., Pölczmann, Gy., Kalló, D.: Investigation of Hydrodearomatization of Prehydrogenated Gas Oil Fractions on Pt-Pd/H- 8

9 USY Catalysts, Topics in Catalysis, 2007, 45(1-4), , DOI: /s (Impact factor: 2,36) 27 Varga, Z., Hancsók, J., Nagy, G., Pölczmann, Gy., Kalló, D.: Upgrading of Gas Oils: The HDS Kinetics of Dibenzotiophene and Its Derivates in Real Gas Oil, Topics in Catalysis, 2007, 45(1-4), , DOI: /s z (Impact factor: 2,36) 28 Nagy, G., Pölczmann, Gy., Kalló, D., Hancsók, J.: Investigation of hydrodearomatization of gas oils on noble metal/support catalysts, Chemical Engineering Journal, 2009, 154, (Impact factor: 2,816) 29 Hancsók, J., Kovács, S., Pölczmann, Gy., Kasza, T.: Investigation the effect of oxygenic compounds on the isomerization of bioparaffins over Pt/SAPO- 11, Topics in Catalysis, 2011, 54, (Impact factor: 2,624) 30 Nagy G., Hancsók J., Varga Z., Pölczmann G.: Investigation of Aromatics Reduction in Low Sulphur Gas Oil, 42nd International Petroleum Conference, Bratislava, October 11th-12th, 2005, pp. 1-12, ISBN X (CD-ROM) 31 Nagy, G., Hancsók, J., Varga, Z., Pölczmann, Gy.: "Hydrodearomatization of gas oil fraction on Pt-Pd/H-USY catalyst", 7th International Symposium MOTOR FUELS 2006, Slovakia, Tatranské Matliare, június , in Proceedings (ISBN ), Varga, Z., Hancsók, J., Nagy, G., Pölczmann, Gy.: Quality improvement of heavy gas oils on NiMo and CoMo catalysts, 7th International Symposium MOTOR FUELS 2006, Slovakia, Tatranské Matliare, június , in Proceedings (ISBN ), Nagy, G., Hancsók, J., Varga, Z., Pölczmann, Gy.: "Investigation of hydrodearomatization of prehydrogenated gas oil fractions on PtPd/H-USY catalysts", 12th Nordic Symposium on Catalysis, Norway, Trondheim, május , Kiadvány (ISBN: ), Varga, Z., Hancsók, J., Nagy, G., Pölczmann, Gy., Kalló, D.: Upgrading of gas oils: the HDS kinetics of dibenzotiophene and its derivatives in real gas oil, 12th Nordic Symposium on Catalysis, Norway, Trondheim, május , Kiadvány (ISBN: ), Pölczmann, Gy., Hancsók, J., Nagy, G., Varga, Z.: Hydrodearomatization of Prehydrogenated Gas Oils on Pt-Pd/USY Catalyst, 6th International Colloquim, Fuels 2007, Germany, Esslingen, január , In Proceedings (ISBN ), Nagy, G., Hancsók, J., Pölczmann, G., Varga, Z., Kalló, D.: Study on the effect of sulphur and nitrogen content of gas oil on the hydrodearomatization activity of Pt-Pd/USY catalysts, Chemical Engineering Transactions (Proceeding of The 8th International Conference on Chemical and Process Engineering), 2007, 11, Gy. Pölczmann, G. Nagy, Z. Varga, J. Hancsók: Hydrodesulphurization and hydrodearomatization of gas oil derived from Hungarian crude oil, EuropaCat VIII, Extended Abstracts (CD), 2007, P Gy. Pölczmann, Sz. Magyar, J. Hancsók, J. Baladincz: Modern base oils from Hungarian crude slack wax, 16th International Colloquium Tribology, Book of Synopses (CD), 2008, 9 oldal 39 Gy. Pölczmann, J. Hancsók, J. Baladincz: Hydroisomerization of Hungarian crude slack wax on Pt/SAPO-11 catalyst, Lubrication Management and Technology 08, Full Scientific Proceedings (CD), ISBN:

10 1, 2008, B Nagy, G., Pölczmann, Gy., Kalló, D., Hancsók, J.: Investigation of Hydrodearomatization on Noble Metal/Support Catalysts, 8th International Symposium MOTOR FUELS 2008, Tatranské Matliare, június , In Proceedings - Part 1 (ISBN ), Nagy, G., Hancsók, J., Pölczmann, Gy., Varga, Z., Kalló, D.: Investigation of two-stage hydrodearomatization of gas oils, 5th International Conference on Environmental Catalysis, Belfast, augusztus 31. szeptember 3. In Proceedings Hancsók, J., Nagy, G., Pölczmann, Gy., Beck, Á., Kalló, D.: Hydrodearomatization of sulphur and nitrogen containing gas oils on bimetallic catalysts, Studies in Surface Science and Catalysis, Zeolites and Related Materials: Trends, Targets and Challenges, Proceedings of 4th International FEZA Conference, 2008, 174-B, ISBN: , Nagy, G., Hancsók, J., Pölczmann, Gy., Varga, Z., Kalló D.: Investigation of Hydrodearomatization of Gas Oils on Noble Metal/Support Catalysts XVIII International Conference on Chemical Reactors, Abstracts, Malta, szeptember 29. október Gy. Pölczmann, J. Hancsók, J. Baladincz: Investigation of Production of High Viscosity Index Base Oil by Catalytic Way, Interfaces 08, CD Proceedings, ISBN: , 2008, 12 oldal 45 J. Hancsók, J. Baladincz, Gy. Pölczmann: Production of High Quality Base Oil and Gas Oil from Hungarian Crude Slack Wax, 13th Nordic Symposium on Catalysis, Book of Abstracts, 2008, Nagy G., Hancsók J., Varga Z., Pölczmann G.: Környezetbarát dízelgázolajok előállítása II. Gázolajpárlatok aromástartalmának csökkentése, Magyar Kémikusok Lapja, 2006, 61(1), Magyar, J., Hancsók, J., Nagy, G., Pölczmann, Gy.: Környezetbarát dízelgázolajok előállítása, III. Gázolajpárlatok hidegfolyási tulajdonságainak javítása katalitikus úton, Magyar Kémikusok Lapja, 2006, 61(2), Szalmásné Pécsvári G., Hancsók, J., Nagy, G., Pölczmann, Gy.: Kénmentes és csökkentett aromástartalmú motorhajtóanyagok előállítása párlatok hidrokrakkolásával, Magyar Kémikusok Lapja, 2006, 61(3), Magyar, J., Hancsók, J., Krár, M., Pölczmann, Gy.: Újgenerációs biomotorhajtóanyagok II., Magyar Kémikusok Lapja, 2006, 61(9-10), Baladincz, J., Hancsók, J., Magyar, Sz., Pölczmann, Gy.: Környezetbarát motorolajok I. Kőolajeredetű alapolajok előállítása: hidrokrakkolás, Magyar Kémikusok Lapja, 2006, 61(12), Hancsók, J., Baladincz, J., Magyar, Sz., Pölczmann, Gy.: Környezetbarát motorolajok II. Kőolajeredetű alapolajok előállítása: paraffin szénhidrogének izomerizálása, Magyar Kémikusok Lapja, 2007, 62(1), Varga Z., Hancsók J., Nagy G., Pölczmann Gy.: Gázolajpárlatok heteroatomeltávolításának vizsgálata átmentifém-szulfid katalizátorokon, Műszaki Kémiai Napok 06 - Conference Proceedings (ISBN ), 2006, Nagy G., Hancsók J., Varga Z., Pölczmann Gy.: Középpárlatok 10

11 aromástartalmának csökkentési lehetőségei, Műszaki Kémiai Napok 06 - Conference Proceedings (ISBN ), 2006, Pölczmann Gy., Hancsók J., Baladincz J.: Korszerű alapolajok előállításának kulcskérdései, Műszaki Kémiai Napok 08 Conference Proceedings (ISBN ), 2008, Pölczmann Gy., Hancsók J.: Nagy izoparaffin-tartalmú gázolajok előállításának vizsgálata, Műszaki Kémiai Napok 09 Conference Proceedings (ISBN ), 2009, Other publications 56 Kovács, S., Pölczmann, Gy., Hancsók, J.: Investigation Of Storage Stabilty of Biodiesels, Hungarian Journal of Industrial Chemistry, 2011, 39 (3), Beck, Á., Pölczmann, Gy., Hancsók, J.: Investigation of thermal-, oxidationand storage stability of biodiesel containing diesel fuel, World Bioenergy 2008 Conference & Exhibition, Sweden, Jönköping, május In Proceedings of Poster Session, Á. Beck, M. Krár, Gy. Pölczmann, J. Hancsók.: Development of Multifunctional Additives for New Generation Biofuels, Bioenergy 2009, Book of Proceedings, 2009, ISBN: , Beck, A., Pölczmann, Gy., Hancsók, J.: Improving the compatibility of multifunctional detergent-dispersant additives, 17th International Colloquium Tribology, Stuttgart/Ostfildern, január , In Book of Synopsis 53., In Proceedings 4 pp 60 Varga Z., Hancsók J., Pölczmann G.: Etanoltartalmú dízelgázolajok, MOL Szakmai Tudományos Közlemények, 2005, 2, Kovács, S., Pölczmann, Gy., Beck, Á., Holló, A., Hancsók, J.: "Biodízelek tárolási stabilitásának vizsgálata", Műszaki Kémiai Napok 11, Conference Proceedings, ISBN: , 2011, Pölczmann, Gy., Holló, A., Hancsók, J.: Különböző összetételű biodízelek tárolási stabilitásának vizsgálata, Mobilitás és környezet: Járműipar, energetika és környezetvédelem konferencia, Veszprém, július 9-11., CD Proceedings, abstract 4.4. Patent application: Eller Z.; Hancsók J.; Kasza T.; Pölczmann Gy.; Rosenbergné Mihályi M.; Szegedi Á.; Szoboszlai Zs.; Valyon J.; Varga Z.: KATALIZÁTOR ÉS ELJÁRÁS PARAFFIN SZÉNHIDROGÉNEK SZELEKTÍV HIDROIZOMERIZÁLÁSÁRA ÉS ELJÁRÁS A KATALIZÁTOR ELŐÁLLÍTÁSÁRA, 2012, number:

12 5. SCIENTOMETRIC DATAS Base publications of the PhD dissertation: 10 summarized impact factor: 2,624 Publications concerning the topic of the PhD dissertation: 45 summarized impact factor: 10,16 Other publications: 7 Total number of publications: 62 - in international journal: 11 - first author or corresponding author: 3 - in hungarian journal: 12 - in conference proceedings: 39 Patent application: 1 Total quotation, without self quotations: (in hungarian and foreign books, in hungarian and foreign lectorated journals, in foreign patents, in foreign PhD dissertations and studies) 13 Other quotations of the dissertation: (in hungarian PhD-, diplom- and other dissertations) 54 Summarized impact factor of the publications: 12,721 Veszprém, 2013 May 12