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Abstract

Wood pellets are classified as a solid biomass type. They are one of the most popular bio-heating fuels used in Europe, especially in the small heating sector, where pellets are burned in low-power domestic boilers. The pellets and automatic pellet-fired heating devices gained popularity due to the increasing air pollution (smog) problem and the low emission limiting campaigns associated with it. Wood pellets are formed as a result of small forestry particles mechanical compression (mainly conifers originated) and they are listed among renewable energy sources. The purpose of the presented studies was to compare the quality of wood pellets used for pellet-fired boilers and to identify, qualitatively and quantitatively, impurities marked in the samples obtained from the domestic market. The application of petrographic analyses, applied so far in relation to fossil fuels, is a presented work innovation for wood pellets. The microscopic analyses were performed on both certified (ENplus/DINplus) and uncertified wood pellets available on the market. Unfortunately, the analysis revealed that the quality requirements were not met, because of the unacceptable contamination presence. The unacceptable organic inclusions in the analyzed samples are fossil coals and their derivatives, coke, and polymeric materials of natural origin. Unacceptable inorganic inclusions determined in the analyzed samples were: glass, slag, rust, pieces of metal, stone powder, plastic, and polymeric materials of inorganic origin.
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Abstract

The article focuses on multicomponent system separation with the use of an innovative membrane-based technique i.e. pervaporation. Pervaporation is a membrane technique for separation of liquid mixtures on solid nonporous membranes. Pervaporation is used in this study to separate a quaternary system acetone-butanol-ethanol-water. Such a system may be derived from ABE fermentation process, and the resulting product, biobutanol, is a potential biofuel and may be used in internal combustion engines. Experiments in the study involving concentration of butanol by pervaporation were performed using PERVAP 4060 flat-sheet commercial membrane. To describe the PV process a semi-empirical approach was used. As a result of experiments and calculations permeance coefficients were obtained. Separation and permeance factors were calculated to assess the efficiency of the system separation. Beforehand, activity coefficients were determined for all the components of the mixture with the NRTL equation. Separation coefficients for all the components differed depending on process parameters: concentration, feed flow rate and process temperature. The study confirmed the separation effect of the quaternary system. The most interesting results were obtained for the concentration of butanol. Pervaporation allows to concentrate butanol over 10 times. The permeance coefficient reached for butanol an average value of 7.06·10-3 in comparison with the results for ethanol 3.24·10-2 and acetone 1.83·10-2 [kmol(m2h)-1]. The temperature change from 50 to 70°C led to an increased permeance factor and there was no apparent effect on it in the feed flow rate. Due to the hydrophobicity of the membrane water fluxes in the quaternary system were negative.
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Abstract

The research issues discussed in the paper concentrate on the participation of the municipal services sector in shaping local development in the commune. The aim of the study is to verify the actual level of involvement of this sector in the development process of the commune, and the thesis is: “The activities of the municipal services sector are one of the factors shaping local development in the commune.” The basic research method is a critical review of domestic and foreign literature and participant observation.
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