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• Submerged aquatic plant (Vallisneria spiralis and Egeria densa) utilisation as a biogas cleaner and feedstock of co-digestion

  172-180

  Gábor Nagy

  Views:

  195

  Biogas was produced from sheep manure and two types of submerged aquatic plant (Vallisneria spiralis and Egeria densa). The gas cleaning was carried out by a water scrubber, where a significant part of CO2 and H2S can be separated from the gas. A part of water from the scrubber was circulated through an aquatic plant growth tank and the growth of used plants was examined. Addition of E. densa to sheep manure increased gas yield by 8% and the mixing of sheep manure and V. spiralis resulted in 21% increase in gas yield. With the used scrubber, 70-80 vol% methane content can be reached in the cleaned biogas, and the water from the scrubber (which contained dissolved CO2 and H2S) resulted in 56-87% increase in size as opposed to 12-44% increase in the control group.

• Adaptability of Powdered Activated Carbon Production from Ground Catering Waste Pyrolysis Coke

  162-171

  Gábor Nagy

  Andrea Simon

  Róbert Géber

  Ádám Rácz

  Views:

  147

  Three mixture of catering waste was pyrolyzed at 650, 725 and 900 °C and the solid residue (coke) was examined for powdered activated carbon production. For this, the carbon content, iodine number, particle size distribution and scanning electron microscopic images were analysed. Based on the carbon content, these cokes are suitable for activated carbon production, which were 60-85 wt.% (depending on the base material and pyrolysis temperature). The studied cokes showed slightly porous structure with smooth surfaces. Because of this, the iodine number was mostly small (13-30). Based on the grinding experiments, 10 minutes of grinding was found to be optimal. After this grinding time, the reached iodine number of powdered activated carbon was 350-610.

• How Implementing Space Capabilities can Realize the Directives of Hungary’s National Security Strategy

  120-141

  Nagy Gábor

  Gergely Singlár

  Zsolt Kelemen

  Dalma Mészáros

  András Tulok

  Csaba Kövesi

  István Danyi

  Sándor Paróczai

  Dénes Hamar

  Lóránt Puszta

  Views:

  359

  The Hungarian Government has released its decree on Hungary’s National Security Strategy, which provides a comprehensive picture of Hungary’s present state of security, sets out the country’s goals and directives to be achieved as well as the necessary government tools and tasks. Significant contributions can be made to the implementation of many of these directives by national space capabilities based on a Hungarian satellite system. In this study we intend to show the validity of this statement by presenting an overview of the legitimacy, features and possible benefits of national space-based capabilities as well as the necessary tasks involved in their implementation.

• Production of Liquid Hydrocarbons from Plastic Wastes

  345-350

  Zsolt Dobó

  Gergő Kecsmár

  Zsófia Jakab

  Gábor Nagy

  Tamás Koós

  Views:

  146

  Thermal pyrolysis of HDPE, LDPE, PP and PS plastic wastes were performed in a batch reactor and the yields of pyrolysis oils and liquid transportation fuels prepared by atmospheric distillation were determined. The gasoline fractions were tested in a traditional spark-ignition engine without any modifications or fuel blending. Fuel consumption and exhaust gas emission (NO_x, CO) were measured and compared to a commercial fuel (RON = 95). PS generated 70.5% gasoline range hydrocarbons from the solid waste, followed by PP with 42.1%, LDPE with 40.8% and HDPE with 37.3%. The fuel consumption was reduced by 9.1-9.4% in the case of PS compared to reference measurement. Reduction in fuel consumption was noticeable at HDPE, LDPE and PP as well. PS gasoline decreased by 91-96%, while HDPE, LDPE and PP more likely increased the CO emission of the engine compared to commercial gasoline. The results show that pyrolysis of plastic wastes is a promising method to generate value added liquid transportation fuels and reduce the footprint of waste accumulation in landfills.

• Innovative Utilization Possibilities of Industrial Wastes from Hungary as Construction Industrial Material

  203-212

  Gábor Mucsi

  Roland Szabó

  Ádám Rácz

  Nóra Papné Halyag

  Mária Nagy Gáborné Ambrus

  Ákos Debreczeni

  Ferenc Móricz

  Ferenc Kristály

  Views:

  125

  The research results carried out at the University of Miskolc Faculty of Earth Science and Engineering in the Center of Excellence of Sustainable Natural Resource Management show that the physical and mechanical properties of the construction industrial products (strength, compactness) made of waste sources can be controlled reasonably by the appropriate processing technologies and under optimized circumstances and characteristics (particle size distribution, specific surface area). It was established that beside the chemical activation, the mechanical activation of solids is an effective tool for improving the product characteristics. However, this modifies the physical as well as structural, mineralogical properties of the raw materials, therefore its determination is of great importance.

• Laboratory-scale gasification of brown coal and char from RDF pyrolysis

  188-193

  Emese Sebe

  Gábor Nagy

  András Arnold Kállay

  Views:

  156

  The pyrolysis is a promising process for producing syngas from wastes. However, the by-product of the technology may contain large quantities of carbon, therefore it is suitable for further syngas production. In this paper we examined the steam gasification of brown coal from Felsőnyárád and char from RDF pyrolysis derived from an experimental pilot plant operating in Zalaegerszeg. We performed our experiments in a laboratory-scale fix-bed reactor at 900 °C. The aim of this work to examine the efficiency of syngas production from pyrolysis char, as well as to explore the similarities and differences of the thermal decomposition of the feedstock materials.