Search results for "ta215"
showing 10 items of 41 documents
Recovery of aliphatic low-molecular-mass carboxylic acids from hardwood kraft black liquor
2015
Abstract During alkaline pulping of wood, substantial amounts of carbohydrates-derived aliphatic carboxylic acids (formic and acetic acids together with various hydroxy acids) are formed and dissolved into the cooking liquor (“black liquor”). These acids with low heating values are considered to be potential feedstocks for the chemical industry but, due to many factors, their straightforward recovery as free acids from black liquor (pH 13–14) is difficult. In this paper, we outlined the partial recovery of volatile formic and acetic acids from the acidified birch ( Betula pendula ) kraft black liquor (pH approximately 2.5) by distillation, and the partial recovery of significant low-molecul…
Phosphotungstic acid (PTA) in the synthesis of 3D CdS superstructures by diffusion assisted hydrothermal method
2015
Abstract In this study, the synthesis of cadmium sulfide (CdS) microstructures by gas diffusion assisted hydrothermal method using phosphotungstic acid (PTA) is reported. The as-synthesized products were characterized by Fourier transform infrared (FTIR), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of PTA dose, thioacetamide amount, time and temperature on the morphology of obtained particles have been studied. In this process, PTA ion host stabilizes the CdS particles against aggregation and thioacetamide plays two roles, being at the same time a sulfur source and a capping ligand. Based on the performed analyses it seems that the thioacetamide is mor…
Microwave-Assisted Esterification of Tall Oil Fatty Acids with Methanol Using Lignin-Based Solid Catalyst
2016
During alkaline pulping significant amounts of lignin, carbohydrates (mostly hemicelluloses), and extractives (tall oil soap and turpentine) are removed from wood feedstock. In this study, the catalytic esterification of fatty acids in tall oil with methanol to produce fatty acid methyl esters under microwave irradiation was performed at 100 °C for 10–60 min. A novel heterogeneous acid catalyst tested for this purpose was synthesized from the hardwood alkali lignin that was precipitated by acidification from the black liquor from soda-AQ pulping. The comparative reaction data were obtained by using other solid catalysts, Amberlyst 15, and p-toluenesulfonic acid. The results showed the highe…
Physical properties of aerosol particles measured from a bubbling fluidized bed boiler
2015
Abstract Increased use of biomass and waste fuels, and the consequent corrosion problem have led to an increased need to study and monitor the combustion processes. This study presents an extensive physical characterization of aerosol particles measured from a bubbling fluidized bed boiler with different fuel mixtures and optional ferric sulfate feeding. The fuel mixtures included bark, sludge, peat and solid recovered fuel. Previously, the characterization of the particles analyzed from a fluidized bed reactor has mainly focused on chemical off-line analysis of collected impactor samples, large coarse mode particles or laboratory-scale reactors. In this study, the focus is in the particle …
Application of Potassium Ion Impregnated Titanium Dioxide as Nanocatalyst for Transesterification of Linseed Oil
2018
The current work comprises the investigation of biodiesel production from linseed oil using TiO2 and a potassium L-tartrate monobasic (C4H5KO6)-modified TiO2 nanocatalyst. Different amounts of C4H5KO6 were considered for TiO2 modification. The nanocatalyst TiO2–0.5C4H5KO6 (1:0.5 molar ratio) showed the best conversion rate for biodiesel production. The nanocatalyst was characterized by FTIR, XRD, TEM, BET, and XPS, and the Hammett indicator–benzenecarboxylic acid titration method was used for basicity measurement. The biodiesel was characterized by GC-MS and 1H and 13C NMR. Furthermore, the optimum reaction parameters for transesterification reaction were analyzed, and the yield was determi…
Rapid one-step solvent-free acid-catalyzed mechanical depolymerization of pine sawdust to high-yield water-soluble sugars
2017
Abstract One-step absolute solvent-free acid-catalyzed mechanical depolymerization of pine sawdust (PSD) and commercially available α-cellulose to water-soluble sugars was carried out using ball milling. For comparison purposes, the commonly reported “solvent-free” mechanocatalytic depolymerization of lignocellulose method, which normally involves three steps (acid impregnation in solvent, vacuum drying, and mechanical depolymerization of lignocellulose), was performed. The 3,5-dinitrosalicylic acid (DNS) method was used to measure the total reducing sugar (TRS) of the obtained sugar solution, and major monosaccharides in the solution were analyzed by capillary electrophoresis (CE). More th…
Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation
2019
Abstract In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent fu…
Sulphate removal over barium-modified blast-furnace-slag geopolymer
2016
Blast-furnace slag and metakaolin were geopolymerised, modified with barium or treated with a combination of these methods in order to obtain an efficient SO4(2-) sorbent for mine water treatment. Of prepared materials, barium-modified blast-furnace slag geopolymer (Ba-BFS-GP) exhibited the highest SO4(2-) maximum sorption capacity (up to 119mgg(-1)) and it compared also favourably to materials reported in the literature. Therefore, Ba-BFS-GP was selected for further studies and the factors affecting to the sorption efficiency were assessed. Several isotherms were applied to describe the experimental results of Ba-BFS-GP and the Sips model showed the best fit. Kinetic studies showed that th…
Influence of torrefaction pretreatment on the pyrolysis of Eucalyptus clone: A study on kinetics, reaction mechanism and heat flow
2016
Abstract The adverse nature of biomass requires specific pretreatment processes to better utilize it in bioenergy applications, and torrefaction is one of the most recognized thermal pretreatment methods. In this regard, we studied the effect of torrefaction pretreatment on kinetics, reaction mechanism and heat flow during the pyrolysis of biomass by making a comparative analysis between the pyrolysis of dried and torrefied Eucalyptus wood. Torrefied biomass was produced at three temperatures, namely 250, 275 and 300 °C. Pyrolysis was performed at 700 °C. The char yield during pyrolysis increased from 22.39 percent to 36.34 percent when the torrefaction temperature was increased from 250 to…
Removal of silicon from CFB-derived fly ash leachate in the context of phosphorus recovery
2018
High concentrations of dissolved silica in the acid leachate impose two major challenges on precipitation based recovery of phosphorus (P). Firstly, co-precipitation of colloidal silica in the acidic regimes decreases the purity and value of precipitated P-products. In addition, silica scaling on internal surfaces of equipment is also a problematic issue in industrial operations. Therefore, removal of dissolved silica prior to P-recovery process minimizes the risks of Si-contamination in P-products and Si-scaling. In the present study, silica removal was achieved by accelerated silica polymerization with higher acidity and ionic strength of mineral acid, which also assisted the leaching of …