No abstract

Biogas is very promising renewable energy resource. The number of biogas plants increase every year. Currently there is a demand for new ways of organic waste treatment from production of different commodities. One of the technologies which produce waste is biodiesel production. One of the wastes from the biodiesel production is G-phase which is mainly consisted from glycerol and methanol. The aim of work was to find the effect of G-phase addition, to fermented material, on biogas resp. methane production. Two lab-scale batch anaerobic fermentation tests (hydraulic retention time 14 and 22 days) under mesophilic temperature conditions 38.5 °C have been performed. The positive effect of G-phase addition to methane production has been found. G-phase was added in three different amounts of inoculums volume 0.5 %, 1% and 1.5 %. The highest absolute methane production has been achieved by 1.5 % addition of G-phase. However it was also found difference in specific methane production due to use of different inoculum consisted of swine or cow manure. The specific methane production in hydraulic retention time of 14 days has been for the same G-phase dose 1.5 % higher for swine manure, 0.547 m3∙kg−1 of organics solids compare with cow liquid manure 0.474 m3∙kg−1 of organics solids.

VÍTĚZ, T., KUKLA, R., TRÁVNÍČEK, P.: Physical properties of sand from the waste water treatment plants. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 4, pp. 233-238 The work is focused on characterization of selected physical properties of sewage sand from the waste water treatment plants. Sand is transported into wastewater mainly in areas with a combined se we ra ge system -principally in connection with rainfalls, in case of which it is transported through the sewerage system together with rainwater, but also (within smaller extents) due to leakages of sewerage systems or bad conduct of natural persons and legal entities. The main attention was focused on basic physical parameters such as content of total solid, ash free dry mass, density and granulometry. These material parameters are very o en underestimated so the set of quality data is completly missing, as well as a background for designers of wastewater treatment plants. This paper should be quite useful e.g. for the purpose of technological equipment design in the region of South Moravia.sand, waste water treatment plant, density, granulometry

TRÁVNÍČEK, P., KUKLA, R, VÍTĚZ, T., MAREČEK, J.: Experimental determination of temperatures of the inner wall of a boiler combustion chamber for the purpose of verifi cation of a CFD model. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 1, pp. 235-242 The paper focuses on the non-destructive method of determination of temperatures in the boiler combustion chamber. This method proves to be signifi cant mainly as regards CFD (Computational Fluid Dynamics) simulations of combustion processes, in case of which it is subsequently advisable to verify the data calculated using CFD so ware application with the actually measured data. Verification of the method was based on usage of reference combustion equipment (130 kW) which performs combustion of a mixture of waste sawdust and shavings originating in the course of production of wooden furniture. Measuring of temperatures inside the combustion chamber is -considering mainly the high temperature values -highly demanding and requires a special type of temperature sensors. Furthermore, as regards standard operation, it is not possible to install such sensors without performing structural alterations of the boiler. Therefore, for the purpose of determination of these temperatures a special experimental device was constructed while exploiting a thermal imaging system used for monitoring of the surface temperature of outer wall of the reference boiler. Temperatures on the wall of the boiler combustion chamber were determined on the basis of data measured using the experimental device as well as data from the thermal imaging system. These values might serve for verifi cation of the respective CFD model of combustion equipment. temperature on the inner wall of a combustion chamber, combustion equipment, thermal imaging measurement, CFD model of the combustion process, heat transmission coeffi cient

Vacuum fluctuation was measured using three different vacuum control methods. Firstly, the use was made of a control valve delivered by the manufacturer; then, an additionally installed frequency converter was used. Lastly, a frequency converter fitted with the stabilisation device prototype was used. First, the control sensitivity according to ISO was measured in all three alternatives. Then the vacuum fluctuation during milking was measured. To conduct the measurements under objectively identified conditions, another measurement was conducted with the air feed during milking being replaced with a precisely defined variable flow rate. The conducted measurement confirmed the fact that when the frequency converter is used, the vacuum fluctuation in the stabilised condition is at the same level as when the control valve is used. If there are sudden changes in the flow rate and the frequency converter is used, the vacuum fluctuation increases. The proposed stabilisation device prototype can reduce the fluctuation.