Applied Mechanics and Materials Vol. 832

Abstract: The aim of the paper is to analyze the application possibilities of the Vortec tube in relation to its energy and economic aspects.The first part consists of an introduction, a description of the energy separation phenomenon in the Vortec tube and the application possibilities and parameters affecting Vortec tube functioning.The second part of the paper deals with the energy balance and economic operational aspects of Vortec tubes produced commercially. The energy balance consists of a thermal calculation of the Vortec tube, the energy-efficiency identification of thermal energy production and a comparison with thermal equipment used in practice. The thesis next continues with an economic analysis of the Vortec tube’s operation, connected with the production of compressed gas. The output of this part is a cost assessment of thermal energy production by means of the Vortec tube and its economic classification in the thermal resources generally used in Slovakia.The last part of the paper includes a static thermal calculation of a dryer using hot air produced by the Vortec tube from the point of view its thermal and temperature potential.

Abstract: In this paper, we will present the research findings concerning relationships between technological and material variables (parameters) during densification of selected types of herbaceous biomass. In general during the biomass densification can be recognized various technological and also material variables which significantly influence the final solid biofuels quality. In case of herbaceous biomass densification there are some important differences with comparing the wooden biomass. These differences come from the material (herbaceous) composition and also from material structure and influencing also lonely treatment, densification and also the combustion of final briquettes from herbaceous biomass. The main goal of presented experimental research is to determine the relationship between compression pressure, compression temperature and raw material particle size. Experimental research described in this paper was realized by single-axis densification, which was represented by experimental pressing stand. The impact of investigated variables on the final briquettes density and briquettes dilatation was determined. Mutual interactions of these variables on final briquettes quality are showing the importance of mentioned variables during the densification process. The experimental findings presented here are significant from briquettes production point of view and also from densification machines engineering point of view.

Abstract: Densification process of biomass to the form of high-grade solid biofuel (briquette or pellet) is influenced by amount of technological factors. Size fraction and moisture content of raw material have the most importance. The densification process may be describing by complicated mathematical models based on behaviour of pressed particular matter. Therefore it is complicated to energy optimize the process. This paper deals with a methodology for determining the compressibility for pine sawdust on the basis of experiments. It also specifies the effectiveness criterion for biomass densification in order to optimize the densification process in terms of energy input. The experiments were performed in two stages. The first stage was an experimental investigation of the influence of size fraction and moisture content on the final compressibility of pine sawdust. High-pressure binderless densification of pine processing residues in the form of sawdust was studied. A piston-and-die process was used to produce densified briquettes under 20 °C temperature and at pressure up to 159 MPa. The results show the behaviour of the pressure load when the parameters of the particulate matter are changed. In the second stage, the experiments were evaluated and optimized to achieve minimum energy input of the process and a maximum degree of densification. For this purpose the Effectiveness Criterion for Densification was designed

Abstract: This contribution describes a design of experime ntal reactor for decomposing the process of gasses with different contents of hydrocarbons (CH ₄ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₆ , C ₃ H ₈ ) . It shows pyrolysis process as a possible source for synthesis gas production . The mathematical modeling ( Ansys Fluent) was used to predict maximal temperature and velocity in three designs and the best result was chosen for manufacturing. Optimal dimensions and material s were chos en basing on the analysis. The ch emical analysis is a second step of research and it is not used in this article .

Abstract: At present, deposition of garbage in landfills is one of the most popular methods to dispose of solid waste produced in municipal areas. In a landfill, large amounts of organic garbage is deposited, where certain types of bacteria flourish and decompose the garbage, whereby heat is produced as by-product. During the decades of operation, considerable quantities of heat are generated in these microbiologically active zones. In such zones, the temperature is typically about 40-60 °C. Knowing this quantities could obviously help planning an energy management system. In this respect, the objective is to extract as much heat from the landfill as possible, and utilize it for applications such as space heating, domestic hot water production, greenhouses, etc. The present paper aims to outline the methods of estimation of the amount of heat that is produced in a landfill during the decades of its operation. The methodology of measurement of thermal conditions and of the heat output capacity is presented, with an example of data, collected so far.

Abstract: This article focuses on the use of alternative renewable energy sources (waste and biomass) as a full replacement for traditional non-renewable resources. We focus on ways to increase the heating value of the raw materials by drying and pyrolysis, and the possibilities of influencing low heating value of fuels by using pyrolysis products. Pyrolysis generates heat and products, which may be used directly as fuel or after modification as additives for fuels. Pyrolysis is a suitable process for recovery of municipal, biological or contaminated waste. It contributes to a sustainable way of energy production and waste management. Moreover, the production in local conditions from local resources, increases land use, employment in the regions and energy self-sufficiency in the state. With combined production of fuels (pellets, briquettes) from biomass, wastes and pyrolysis products we expect to increase the heating value of well over 20 MJ.kg^-1.

Abstract: It is still necessary to be interested in the efficient production of heat and electricity nowadays. The prevailing method of production of electricity in the Czech Republic has been the conversion of heat energy released during the combustion of fuels.This fact is also associated with a large field of diagnostic measurements focused on monitoring the efficiency of this conversion and the subsequently emerging pollutants. This specific area of diagnostic measurements has its characteristic features, which are descripe in this article.

Abstract: Possibilities of anaerobic processing of substrates rich in sulphur were studied. High concentrations of sulphur cause problems when contained in biogas, as well as inhibition by sulphides in anaerobic processes. The impact of ferrous chloride on anaerobic processes, directly dosed to the anaerobic reactor was studied. This sulphur removal method is commonly known, though the objective of our study was to identify problems when it is applied on substrates rich in sulphur. Waste biomass from cystine production was used as substrate, which is produced in large quantities (17000 t/y) by Biotika, a.s. Slovenská Ľupča and requires processing; sulphur content range from 4 up to 5 % in the biomass. Specific biogas production was 0.410 m³/kg COD i.e. 0.737 m³/kg VSS, while 77 % sulphide inhibition occurred after several dose repetitions. Inhibition decreased to 25.4 % during long-term processing of cystine biomass in a mixed anaerobic reactor. Ferrous chloride dosing, however, resulted in high excess sludge generation, lower organic content in the sludge and high concentration of dissolved inorganic salts. These factors may lead to secondary problems in long-term processing of cystine biomass.

Abstract: Satisfying of increasing demands of society has often resulted in uncontrolled discharges of harmful substances into the atmosphere. The situation is gradually improving over the past 50 years, but the environmental impact is still evident and it must be monitored and evaluated. Reduction of emissions released into the atmosphere and reduction of air pollution impact on the Earth surface occurs due to development of new methods and technologies in the industry and legislation. This paper deals with the possibilities of the two methods of the SO₂ concentration measurements - sorption - cumulative and ultraviolet fluorescent method at the location of the power plant Novaky. In the imission area is built automated measuring station (AMS) Oslany (operated by ENVITECH, managed by Slovak Hydrometeorological Institute Bratislava) as the measure of the total concentration of the pollutant. The research have shown that the maximum concentration detected in this area reached up to 64.46 µg.m^-3 of SO₂

Abstract: Vehicles are the dominant source of many air pollutant emissions in urban areas. The effects caused by vehicle emissions have been receiving increasing attention, and recent epidemiological studies show elevated risks of cardiovascular morbidity, cancer, allergic diseases for drivers, commuters and individuals living near roadways. During the experimental research conducted in this paper, emission characteristics of Otto 1.1 EFI engine were investigated in varying operating modes in order to adequately simulate the movement of the Fiat Punto Classic (FPC) passenger car in city driving conditions in line with the New European Driving Cycle (NEDC). The NEDC is a stylized cycle, with periods of constant acceleration, deceleration and constant speed, and it is supposed to represent the typical usage of a passenger car in Europe. The analysis of exhaust gas samples was conducted by using the gas chromatography technique in combination with the photoionization detector (GC/PID). The results of emission tests indicate high concentration levels of toluene in the exhaust gas mixtures, ranging from 7.07 to 116.87 ppm. The total mass of the emitted toluene after 100 km of driving in accordance with the NEDC was 7.7647 g.