Influence of temperature on biogas production from fermentation residues

Fermentační zbytek z bioplynové stanice má potenciál ke zbytkové produkci bioplynu. Bylo provedeno testování této produkce bioplynu a metanu s dobou testování 180 dní při teplotách 41 oC, 27 oC a 16 oC. Nejvíce bioplynu bylo vyprodukováno vzorkem A při teplotním režimu 41 oC, a sice 152.9 ⨯ 10-3 m3.kg-1. U metanu stejný vzorek vyprodukoval při 41 oC až 86,4 ⨯ 10-3 m3 . kg-1. Statisticky významný rozdíl byl shledán mezi měrnou produkcí bioplynu i metanu všech variant testu. Dále byla produkce bioplynu a metanu v závislosti na teplotě proložena polynomem druhého stupně. Rovnice polynomu pro bioplyn můžeme napsat ve tvaru Y = (-42,927 +- 38,349) + (5,223 +- 2,9566) . X + (-0,0181 +- 0,0510) . X2, (R2 = 0,957) a pro metan Y = (-26,85 +- 27,94) + (2,3296 +- 2,1541) . X + (0,0033 +- 0,0372) . X2, (R2 = 0,939). Tyto rovnice umožňují následné určování případů zastřešení a vytápění konkrétních uskladňovacích jímek na fermentační zbytek s ohledem na dobu trvání testu 180 dní. Teoretická produkce elektrické energie kogenerační jednotou při využití průměrné produkce metanu za 180 dní testu, vzniklého při 41 oC je 70 685,0 kWh.The fermentation residue from the biogas plant has the potential for residual biogas production. This biogas and methane production was tested during 180 days at 41 oC, 27 oC and 16 oC. Most of the biogas was produced by sample A with temperature regime of 41 oC, where the specific productionof this sample was 152.9 ⨯ 10-3 m3 . kg-1. The same sample produced at 41 oC volume of 86.4 ⨯ 10-3 m3 . kg-1of methane. A statistically significant difference was found between the specific biogas and methane production of all test variants. Furthermore, the production of biogas and methane, depending on temperature, was interleaved by a second degree polynomial. The polynomial equations for biogas can be written in the form Y = (-42,927 +- 38,349) + (5,223 +- 2,9566) . X (-0,0181 +- 0,0510) . X2, (R2 = 0,957) and for methane Y = (- 26.85 +- 27.94) + (2.3296 +- 2.1541) . X (0.0033 +- 0.0372) . X2, (R2 = 0.939). These equations allow the subsequent determination of cases of roofing and heating of specific storage wells to the fermentation residue with respect to the test duration of 180 days. The theoretical electricity production by the cogeneration unit using the average methane production for 180 days of the test, generated at 41 oC, overall 70 685.0 kWh.O

The role of mineral phases in the biogas production technology

In the field of electric power industry, renewable energy sources, fertilisers, reclamation, and waste management, biomass is widely studied and used. Minerals are present in every step of biogas transformation, but their forms, occurrence, and composition have not been studied yet. However, there is no comprehensive study research that would address the presence of mineral phases in the process of biogas production. This aim of the study is determination of the amount and composition of the mineral phases present in fermentation residues resulting from different production technologies. Digestate mineral composition was analysed using 46 samples from agricultural biogas plants and university testing biogas reactor. The majority of samples contained the amorphous phase. Minority phases consisted of quartz, albite, orthoclase, muscovite, and amphibole. Opal-CT was found in eleven samples (1.26 to 12.1% wt.). The elements present in gas-liquid fluids or in liquids, gases and aerosols within the biogas technology system may create mineral phases, namely the amorphous phase or the crystalline phase under certain conditions. Opal-CT may enter the fermenter as part of plant tissues referred to as phytoliths, or as an unwanted admixture of different origin. It may also originate from the present amorphous SiO2.Web of Science251595

Isothermal Kinetic Analysis of the Thermal Decomposition of Wood Chips from an Apple Tree

The thermal decomposition of wood chips from an apple tree is studied in a static air atmosphere under isothermal conditions. Based on the thermogravimetric analysis, the values of the apparent activation energy and pre-exponential factor are 34 ± 3 kJ mol−1 and 391 ± 2 min−1, respectively. These results have also shown that this process can be described by the rate of the first-order chemical reaction. This reaction model is valid only for a temperature range of 250–290 °C, mainly due to the lignin decomposition. The obtained results are used for kinetic prediction, which is compared with the measurement. The results show that the reaction is slower at higher values of degree of conversion, which is caused by the influence of the experimental condition. Nevertheless, the obtained kinetic parameters could be used for the optimization of the combustion process of wood chips in small-scale biomass boilers

Influence of the Combine Harvester Parameter Settings on Harvest Losses

This paper deals with the relationship between grain yield and grain losses during harvest. Measurements were carried out on a combine harvester with axial harvesting device allowing various adjustments to combine harvester parameter settings, such as rotor speed, gap between separator and rotor, fan speed, holes of the upper and lower sieves. Values of harvest losses in combine harvester with custom settings for the given crops were compared with values of losses obtained by a harvester with manufacturer’s recommended settings. This paper observes the losses in grains of spring barley and winter wheat crops. All the measurements made showed lower grain losses when the combine harvester settings were customized. In general, custom settings provided quantitative losses lower by 0.198% than settings recommended by manufacturer