Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 7 Articles
The issue of residues and industrial effluents represents an unprecedented environmental challenge in terms of recovery, storage,\nand treatment. This work discusses the perspectives of treating effluents through anaerobic digestion as well as reporting the\nexperience of using an upflow anaerobic sludge blanket (UASB) reactor as biorefinery annex in a pulp and paper industrial plant to\nbe burned in the boilers. The performance of the reactors has shown to be stable under considerable variations in load and showed\na significant potential in terms of biogas production. The reactors UASB treated 3600.00m3 of effluent daily from a production of\n150.00 tons. The biogas generation was 234.000 kg/year/mill, equivalent in combustible oil. The results of methane gas generated\nby the anaerobic system UASB (8846.00 kcal/m3) dislocate the equivalent of 650.0 kg of combustible oil (10000.00 kcal/kg) per day\n(or 234.000 kg/year). The production of 8846.00Kcal/m3 of energy frombiogas canmake a run at industrial plant for 2 hours. This\nsubstitution can save US$ 128.700 annually (or US$ 550.0 of fuel oil/tons). The companies are invested in the use of the biogas in\ndiesel stationary motors cycle that feed the boilers with water in case of storage electricity....
Bioconversion of hemicellulosic sugars into second generation (2G) ethanol plays a pivotal role in the overall success of biorefineries.\nIn this study, ethanol production performance of a novel xylose-fermenting yeast, Scheffersomyces shehatae UFMG-HM 52.2,\nwas evaluated under batch fermentation conditions using sugarcane bagasse (SB) hemicellulosic hydrolysate as carbon source.\nDilute acid hydrolysis of SB was performed to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH). It was concentrated,\ndetoxified, and supplemented with nutrients in different formulations to prepare the fermentation medium to the yeast evaluation\nperformance. S. shehataeUFMG-HM52.2 (isolated fromBrazilianAtlantic rain forest ecosystem) was used in fermentations carried\nout in Erlenmeyer flasks maintained in a rotator shaker at 30?C and 200 rpmfor 72 h. The use of a fermentation medium composed\nof SBHHsupplemented with 5 g/L ammonium sulfate, 3 g/L yeast extract, and 3 g/L malt extract resulted in 0.38 g/g of ethanol yield\nand 0.19 g L.h of volumetric productivity after 48 h of incubation time....
Resorcinol-formaldehyde resin polymer was used as rawmaterial for preparation of carbon spheres. Samples were treated with CO2\nflow at 850?C by varying activation times.The CO2 activation granted better pore development of pore structure. The experimental\ndata of CH4 adsorption as a function of equilibrium pressure was fitted by Langmuir and Dubinin-Astakhov (D-A) models. It was\nconcluded that the high surface area and micropore volume of carbon spheres did unequivocally determine methane capacities.\nIn addition, a thermodynamic study of the heat of adsorption of CH4 on the carbon spheres was carried out. Adsorption of CH4\non carbon spheres showed a decrease in the adsorption heat with CH4 occupancy, and the heat of adsorption fell from 20.51 to\n12.50 kJ/mol at 298Kand then increased to a little higher values at a very high loading (>0.70), indicating thatCH4/CH4 interactions\nwithin the adsorption layer became significant...
Three materials of perovskite structure, CaMn1??M?O3?? (M = Mg or Mg and Ti), have been examined as oxygen carriers in\ncontinuous operation of chemical-looping combustion (CLC) in a circulating fluidized bed system with the designed fuel power\n300W. Natural gas was used as fuel. All three materials were capable of completely converting the fuel to carbon dioxide and water\nat 900?C. All materials also showed the ability to release gas phase oxygen when fluidized by inert gas at elevated temperature (700ââ?¬â??\n950?C); that is, they were suitable for chemical looping with oxygen uncoupling (CLOU). Both fuel conversion and oxygen release\nimproved with temperature. All three materials also showed good mechanical integrity, as the fraction of fines collected during\nexperiments was small.These results indicate that the materials are promising oxygen carriers for chemical-looping combustion....
Desalination wastewater, which contains large amount of salt waste, might lead to severely environmental pollution. This study\nevaluated the effect of dilution rate (0.1 ? ???? ? 0.3 day?1) on microalgal biomass productivity, lipid content, and fatty acid profile\nunder steady-state condition of Chlorella vulgaris supplementedwith concentrated desalination. Continuous culture was conducted\nfor 55 days. Results show that the biomass productivity (????????) varied from 57 to 126mg L?1 d?1 (dry mass) when the dilution rate\nranged from 0.1 to 0.3 day?1. At lowest dilution rate (???? = 0.1 day?1), the continuous culture regime ensured the highest values\nof maximum biomass concentration (???????? = 570 �± 20mL?1) and protein content (52%). Biomass lipid content was an increasing\nfunction of ????. The most abundant fatty acids were the palmitic (25.3 �± 0.6%) at ???? = 0.1 day?1 and the gamma-linolenic acid\n(23.5 �± 0.1%) at ???? = 0.3 day?1 ones. These fatty acids present 14 to 18 carbons in the carbon chain, being mainly saturated and\npolyunsaturated, respectively. Overall, the results show that continuous culture is a powerful tool to investigate the cell growth\nkinetics and physiological behaviors of the algae growing on desalination wastewater....
The interior ballistics simulations in 9mm small gun chamber were conducted by implementing the process into the mixture\nmultiphase model of Fluent V6.3 platform. The pressure of the combustion chamber, the velocity, and the travel of the projectile\nwere investigated. The performance of the process, namely, the maximum pressure, the muzzle velocity, and the duration of the\nprocess was assessed. The calculation method is validated by the comparison of the numerical simulations results in the small gun\nwith practical tests, and with lumped-parameter model results. In the current numerical study, both the characteristics and the\nperformance of the interior ballistic process were reasonably predicted compared with the practical tests results.The impact of the\nweight charge on the interior ballistic performances was investigated. It has been found that the maximum pressure and themuzzle\nvelocity increase with the increase of the charge weight....
This review examines a variety of adsorbents and discusses mechanisms, modification methods, recovery and regeneration, and\ncommercial applications. A summary of available researches has been composed by a wide range of potentially low-cost modified\nadsorbents including activated carbon, natural source adsorbents (clay, bentonite, zeolite, etc.), biosorbents (black gram husk,\nsugar-beet pectin gels, citrus peels, banana and orange peels, carrot residues, cassava waste, algae, algal, marine green macroalgae,\netc.), and byproduct adsorbents (sawdust, lignin, rice husk, rice husk ash, coal fly ash, etc.). From the literature survey, different\nadsorbents were compared in terms of Zn2+ adsorption capacity; also Zn2+ adsorption capacity was compared with other metals\nadsorption. Thus, some of the highest adsorption capacities reported for Zn2+ are 168mg/g powdered waste sludge, 128.8mg/g\ndried marine green macroalgae, 73.2mg/g lignin, 55.82mg/g cassava waste, and 52.91mg/g bentonite. Furthermore,modification of\nadsorbents can improve adsorption capacity. Regeneration cost is important, but if consumption of virgin adsorbent is reduced, then\nmultiple economic, industrial, and environmental benefits can be gained. Finally, themain drawback of the already published Zn2+\nadsorption researches is that their use is still in the laboratory stage mostly without scale-up, pilot studies, or commercialization....
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