Search results for "Energy engineering"
showing 10 items of 1099 documents
Innovation Activities in Baltic Countries
2013
Abstract Article discusses a research framework which brings together variety of related factors to innovation process on the basis of systemic review of theoretical and empirical studies. Aim – investigate human capital, R&D, cooperation with external environment, on innovation oriented organizational culture, and market orientation, state policy relation to the process of innovation creation in Latvian, Lithuanian and Estonian innovative enterprises. Main research methods used. Monographs method - information collection and compilation of the influential factors on innovation creation. This method makes it possible to carry out a detailed study of the object, based on scientific literatur…
Dynamic Modeling and Driving Cycle Prediction for a Racing Series Hybrid Car
2014
International audience; This paper presents Noao, a plug-in series hybrid racing car equipped with an engine/generator set as range extender. To determine the velocity profile, i.e., performance of the car and its power profile, a dynamic model for this car is developed using pedal position as input. This value is easy to measure, representative for race cycles, and presents a novelty. The model is validated with the results from experiments. An analysis based on the map of Magny-Cours racing circuit and drivers pedal action on certain zones of the circuit is formulated and is used as a prediction tool to determine drivers inputs on other racing circuits and generate driving schedules. The …
Biomethane production from maize and liquid cow manure – Effect of share of maize, post-methanation potential and digestate characteristics
2013
Abstract This study investigates the co-digestion of liquid cow manure and maize with different share of maize in continuously stirred tank reactors (CSTRs). The objective was to determine the methane yield of reactor and the post-methanation potential of the digestate from different reactor trials. The highest specific methane yield (259 Nl CH 4 /kg volatile solids (VSs)) was obtained when the share of maize in the feedstock was 40% (VS) and the second highest specific methane yield was when the proportion of maize was 60% (VS) (234 Nl CH 4 /kg VS). The post-methanation potential of the digestate was determined in batch assays. The minimum value (maize 40%, 75 ± 1 Nl CH 4 /kg VS feed ) occ…
Hydrogen trapping: Synergetic effects of inorganic additives with cobalt Sulfide absorbers and reactivity of cobalt polysulfide
2012
International audience; The biphasic product CoS2 + Co(OH)(2) obtained by oxidation of cobalt sulfide is known to trap hydrogen at room temperature and low pressure according to a balanced reduction equation. Adding various inorganic compounds to this original absorber induces their reduction by hydrogen in the same conditions at a significant rate: (i) excess cobalt hydroxide is reduced to metallic cobalt; (ii) nitrate ions are reduced to ammonia; (iii) sulfur and sodium thiosulfate are reduced to H2S or NaHS and Na2S, respectively. Without a hydrogen absorber these inorganic compounds are not reduced by H-2, suggesting synergetic effects involving H-2 and the hydrogen absorber. Amorphous …
Hydrogen underground storage—Petrographic and petrophysical variations in reservoir sandstones from laboratory experiments under simulated reservoir …
2018
Abstract Fluctuating energy production by renewables is one of the main issues in transition times of energy production from conventional power plants to an energy production by renewables. Using excess produced electricity (windy/sunny periods) to convert water to oxygen and hydrogen and storing the hydrogen in depleted oil-, gas fields or sedimentary aquifer structures would provide the option to recover and convert hydrogen to electricity in periods with an energy demand. Research focus is here the pore space in the geological underground where still few studies exist. In static batch experiments up to six weeks long, under different reservoir-specific conditions; regarding pressure, tem…
Hydrogen and methane production in extreme thermophilic conditions in two-stage (upflow anaerobic sludge bed) UASB reactor system
2013
Abstract Two-stage hydrogen and methane production in extreme thermophilic (70 °C) conditions was demonstrated for the first time in UASB-reactor system. Inoculum used in hydrogen and methane reactors was granular sludge from mesophilic internal circulation reactor and was first acclimated for extreme thermophilic conditions. In hydrogen reactor, operated with hydraulic retention time (HRT) of 5 h and organic loading rate (OLR) of 25.1 kg COD/m 3 /d, hydrogen yield was 0.73 mol/mol glucose added . Methane was produced in second stage from hydrogen reactor effluent. In methane reactor operated with HRT of 13 h and OLR of 7.8 kg COD/m 3 /d, methane yield was 117.5 ml/g COD added . These resul…
From determination of the fugacity coefficients to estimation of hydrogen storage capacity: A convenient theoretical method
2015
Abstract The equation of state (EOS) from virial expansion (VE) is used in this work to pave the way for determining the fugacity coefficients of the hydrogen fluid at arbitrary temperature and pressure. The fugacity coefficients from our VE method have more physical meanings than the empirical values. In this way, the hydrogen storage capacity of a novel material model can be estimated by using few density functional theory (DFT) calculations with the aid of a continuum model. The efficient continuum model can provide a more accurate estimation of the hydrogen storage capacity than the pure DFT calculations. Furthermore, the expensive grand canonical ensemble (μNT) simulations combining wi…
Batch dark fermentative hydrogen production from grass silage: The effect of inoculum, pH, temperature and VS ratio
2008
Abstract The potential for fermentative hydrogen (H2) production from grass silage was evaluated in laboratory batch assays. First, two different inocula (from a dairy farm digester and digested sewage sludge) were studied with and without prior heat treatment and pH adjustment. Only the inoculum from the dairy farm digester produced H2 from grass silage. Without heat treatment, methane (CH4) was mainly produced, but heat treatment efficiently inhibited CH4 production. pH adjustment to 6 further increased H2 production. The effects of initial pH (4, 5 and 6), temperature (35, 55 and 70 ∘ C ) and the substrate to inoculum volatile solids (VS) ratio (henceforth VS ratio) (1:1; 1.5:1 and 2:1) …
Metal hydride alloys for storing hydrogen produced by anaerobic bacterial fermentation
2016
Abstract This study reports on hydrogen sorption from bacterial fermentation media with powdered palladium (Pd) and alloys (LaNi5, AB5, and AB2) that are capable of forming hydrides. Mass changes of the powders after incubation in fermentation media were measured by differential thermogravimetry. Composition and concentrations of the gases accumulated during fermentation and absorbed by Pd or the alloys were analyzed by mass spectrometry. The results demonstrated that hydrogen (H2) was absorbed and stored by powdered Pd and alloys directly from nutritional broth. The best sorption was obtained with Pd, followed by alloys AB5 and AB2. Scanning electron microscopy revealed that bacteria were …
Experimental investigation on lithium borohydride hydrolysis
2010
Abstract Lithium borohydride, one of the highest energy density chemical energy carriers, is considered as an attractive potential hydrogen storage material due to its high gravimetric hydrogen density (19.6%). Belonging to borohydride compounds, it presents a real issue to overcome aims fixed by the U.S. Department of Energy in the field of energy, and so crystallizes currently attention and effort to use this material for large scale civil and military applications. However, due to its important hygroscopicity, lithium borohydride is a hazardous material which requires specific handling conditions for industrial aspects. In order to understand much more the reaction mechanism involved bet…