The Experts below are selected from a list of 8583 Experts worldwide ranked by ideXlab platform
Jose María Palacios - One of the best experts on this subject based on the ideXlab platform.
-
Low temperature co pyrolysis of a Low Rank Coal and biomass to prepare smokeless fuel briquettes
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: M. J. Blesa, J. L. Miranda, M. T. Izquierdo, Rafael Moliner, Jose María PalaciosAbstract:Abstract Smokeless fuel briquettes have been prepared with Low-Rank Coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600 °C with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of Coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture.
-
Low-temperature co-pyrolysis of a Low-Rank Coal and biomass to prepare smokeless fuel briquettes
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: M. J. Blesa, J. L. Miranda, M. T. Izquierdo, Rafael Moliner, Jose María PalaciosAbstract:Smokeless fuel briquettes have been prepared with Low-Rank Coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600 °C with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of Coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture. © 2003 Elsevier Science B.V. All rights reserved.
M. J. Blesa - One of the best experts on this subject based on the ideXlab platform.
-
Low temperature co pyrolysis of a Low Rank Coal and biomass to prepare smokeless fuel briquettes
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: M. J. Blesa, J. L. Miranda, M. T. Izquierdo, Rafael Moliner, Jose María PalaciosAbstract:Abstract Smokeless fuel briquettes have been prepared with Low-Rank Coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600 °C with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of Coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture.
-
Low-temperature co-pyrolysis of a Low-Rank Coal and biomass to prepare smokeless fuel briquettes
Journal of Analytical and Applied Pyrolysis, 2003Co-Authors: M. J. Blesa, J. L. Miranda, M. T. Izquierdo, Rafael Moliner, Jose María PalaciosAbstract:Smokeless fuel briquettes have been prepared with Low-Rank Coal and biomass. These raw materials have been mixed in different ratios and have been pyrolysed at 600 °C with the aim to reduce both the volatile matter and the sulphur content, and to increase the high calorific value (HCV). The co-pyrolysis of Coal and biomass has shown a synergetic effect. The biomass favours the release of hydrogen sulphide during the thermal treatment. This fact can be explained in terms of the hydrogen-donor character of the biomass. Moreover, the optimisation of the amount of binder and the influence of different types of biomass in the blend have been studied with respect to the mechanical properties of the briquettes (impact resistance, compression strength and abrasion). Briquettes prepared with sawdust (S) present better mechanical properties than those with olive stones (O) because of its fibrous texture. © 2003 Elsevier Science B.V. All rights reserved.
Yaowen Xing - One of the best experts on this subject based on the ideXlab platform.
-
Role of molecular simulation in understanding the mechanism of Low-Rank Coal flotation: A review
Fuel, 2020Co-Authors: Rui Zhang, Yaowen XingAbstract:Abstract Flotation is the main method for recovering and reusing fine Low-Rank Coal by taking advantage of the difference in physicochemical properties of the mineral surface, but its efficiency has not yet reached a satisfactory level. Particles, flotation reagents, and air bubbles are highly dispersed and interact with each other in a flotation cell. Therefore, a basic understanding on the fundamental mechanism of the above interactions involved in a Low-Rank Coal flotation system is the prerequisite for improving Low-Rank Coal flotation recovery. In recent years, with the development of theoretical chemistry and computational chemistry, molecular simulation has gradually become a powerful tool for studying Low-Rank Coal flotation, which has shed new light on the molecular structure of Low-Rank Coal and the interfacial interaction in Low-Rank Coal flotation at the molecular or atomic levels. In this paper, we first review the basic theory of molecular simulation, and then we review the recent advances in the molecular structure of Low-Rank Coal. Coal-water, Coal-reagent, Coal-bubble, and Coal-clay interactions are discussed comprehensively from the viewpoint of molecular simulation. This review is closed with a brief conclusion and perspective discussion.
-
enhancement of flotation response of fine Low Rank Coal using positively charged microbubbles
Fuel, 2019Co-Authors: Longwu Wang, Rui Zhang, Zili Yang, Yaowen XingAbstract:Abstract This study investigates the possibility of using positively charged (PC) microbubbles in pulp conditioning to improve the flotation response of fine Low-Rank Coal. The surface properties of the Coal are characterized by means of a zeta potential analyzer, scanning electron microscopy, and X-ray photoelectron spectroscopy. Batch flotation tests are conducted with the use of PC microbubbles, cetyltrimethylammonium bromide (CTAB) solution, and tap water in pulp conditioning. The roles of PC microbubbles in the Coal flotation are illustrated by combining observations of particle–particle and particle–bubble interactions and extended Derjaguin–Landau–Verwey–Overbeek (DLVO) theory calculations. The results indicate that fine Low-Rank Coal is negatively charged and contains a large amount of oxygen. In addition, the rough structure and the presence of numerous impurity mineral particles on the surface of Low-Rank Coal afford adsorption sites for water molecules. These features of the Coal render traditional collectors ineffective, whereas the presence of PC microbubbles significantly enhances flotation recovery. However, increasing CTAB concentration cannot continuously improve flotation performance with the use of PC microbubbles, possibly because the excess CTAB molecules can form bilayer or micelle adsorption structures on the Coal surface, particularly on the mineral surface. The presence of PC microbubbles promotes particle–particle agglomeration and particle–bubble attachment by providing an additional attractive electrical double-layer force and enhancing hydrophobic interactions. The extended DLVO theory calculations agree well with the experimental results.
-
Effects of pore compression pretreatment on the flotation of Low-Rank Coal
Fuel, 2019Co-Authors: Zili Yang, Ming Li, Zijian Ma, Yaowen XingAbstract:Abstract The poor flotation efficiency of Low-Rank Coal in the flotation process is due to the large and rich pore structure on its surface. In this study, the changes in the pore structure before and after pore compression pretreatment were analyzed by a scanning electron microscope and Brunauer–Emmett–Teller analysis. The effects on the flotation were then evaluated by analyzing the results of collector adsorption experiments and flotation kinetics tests. After pore compression, the pore state on Low-Rank Coal surface was from open to half-closed and then closed. Further, the pore volume, specific surface area, and average pore diameter of the particles decreased from 0.02497 to 0.01214 cm3/g, 17.383 to 5.006 m2/g, and 9.6992 to 5.7466 nm, respectively. In addition, the adsorption rate of the collectors improved and the equilibrium adsorption time of n-dodecane decreased from 436 s to 250 s, whereas the adsorption rate of water decreased with the porosity of the Coal after pore compression. Meanwhile, according to the flotation results, the maximum clean Coal yield (74.44%) was obtained within 400 MPa of pressure pretreatment using n-dodecane as a collector; this value is 20.46% points higher than that of raw Coal flotation using n-hexane as the collector. Furthermore, it was also found that a collector with too high a viscosity or too short a carbon chain causes the total cumulative yield of the Low-Rank Coal to decrease. It is anticipated that the results of this work can provide guidance in Low-Rank Coal flotation applications.
-
enhancement of the surface hydrophobicity of Low Rank Coal by adsorbing dtab an experimental and molecular dynamics simulation study
Fuel, 2019Co-Authors: Zili Yang, Rui Zhang, Yaowen XingAbstract:Abstract This study investigated the mechanism of improving the surface hydrophobicity of Low-Rank Coal by adsorbing dodecyltrimethylammonium bromide (DTAB). Experimental tests were conducted to analyze the adsorption characteristic of DTAB on the Coal surface including the adsorption amount, Zeta potential, wetting heat, and X-ray photoelectron spectroscopy measurement. Furthermore, the adsorption configuration, spatial location of the simulation systems, and the Coal–water interaction were investigated by molecular dynamics (MD) simulation at the atomic scale. Experimental results indicate that the hydrophobicity of the Low-Rank Coal first increased, then decreased as the DTAB concentration increased. The electrostatic force plays a dominant role in the adsorption of DTAB on Low-Rank Coal surface. The adsorption of DTAB reduced the wetting heat between water and Low-Rank Coal because the oxygen-containing groups were covered. The decrease in hydrophobicity at high DTAB concentration was due to the formation of a bilayer or micelle adsorption. MD simulation results show that the adsorption of DTAB reduced the thickness of the water adsorption layer. The nitrogen atoms of DTAB were oriented toward the Coal surface, such that the alkyl chains were oriented to the water phase, thereby producing an additional repulsive effect and subsequently inhibiting the adsorption of water molecules. As a result, the number of hydrogen bonds and the interaction energy between water molecules and Low-Rank Coal decreased, indicating that the hydrophobicity of Low-Rank Coal was enhanced.
-
Waste colza oil used as renewable collector for Low Rank Coal flotation
Powder Technology, 2019Co-Authors: Mengdi Xu, Yaowen XingAbstract:Abstract The high cost of Low Rank Coal flotation using diesel as the collector significantly restricts the improvement in economic efficiency of the Coal plant. Waste colza oil (WCO) from the catering industry was used as a renewable and alternative collector for ultrafine Low Rank Coal flotation in this investigation. Scanning electron microscopy (SEM) test was carried out to check the surface morphologies of the Coal sample. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) tests were performed to examine the Coal chemical compositions. The flotation yield using WCO was always higher than that of using diesel, especially at a high dosage. When 6 kg/t dosage was used, 35.68% yield was obtained with WCO, 5.54% higher than that with diesel. The mechanism of WCO used as an alternative collector was discussed based on the induction time, FTIR, and XPS tests. The induction time of the Low Rank Coal after conditioning with 6 kg/t diesel and WCO were 200 ms and 100 ms, respectively, indicating that WCO was a more effective collector for improving the floatability of Low Rank Coal compared with traditional diesel. XPS tests confirmed the adsorption of WCO on Coal surface as the WCO has a large amount of C O groups according to FTIR results. The hydrogen bonding between oxygen-containing groups in WCO and Low Rank Coal surface was responsible for the improvement of floatability and flotation recovery.
L I Xianchun - One of the best experts on this subject based on the ideXlab platform.
-
experimental study on drying and moisture re adsorption kinetics of an indonesian Low Rank Coal
Journal of Environmental Sciences-china, 2009Co-Authors: L I Xianchun, Hui Song, Qi Wang, Chatphol Meesri, T F Wall, Y U JianglongAbstract:Abstract The drying kinetics of an Indonesian Low Rank Coal and moisture re-adsorption of the dried Coal using a thermobalance and a climatic chamber were investigated. Results show that the drying kinetics is best represented by two stages, as a constatnt rate stage folLowed by a rate decay stage. The water removal rate is dependent mainly on drying temperature and Coal sample size. The apparent activation energy ( E ) of drying was 26.58 kJ/mol. A rate equation for drying of the Coal was obtained from the experimental data. The moisture re-adsorption rate was dependent on drying temperature, Coal particle size, and relative humidity of the atmosphere.
Y U Jianglong - One of the best experts on this subject based on the ideXlab platform.
-
experimental study on drying and moisture re adsorption kinetics of an indonesian Low Rank Coal
Journal of Environmental Sciences-china, 2009Co-Authors: L I Xianchun, Hui Song, Qi Wang, Chatphol Meesri, T F Wall, Y U JianglongAbstract:Abstract The drying kinetics of an Indonesian Low Rank Coal and moisture re-adsorption of the dried Coal using a thermobalance and a climatic chamber were investigated. Results show that the drying kinetics is best represented by two stages, as a constatnt rate stage folLowed by a rate decay stage. The water removal rate is dependent mainly on drying temperature and Coal sample size. The apparent activation energy ( E ) of drying was 26.58 kJ/mol. A rate equation for drying of the Coal was obtained from the experimental data. The moisture re-adsorption rate was dependent on drying temperature, Coal particle size, and relative humidity of the atmosphere.
