Oil Agglomeration Research Articles

Fine coal recovery from washery tailings in Turkey by oil agglomeration

In Turkey, coal washeries discharge huge amount of fine coal containing tailings. Loss of economically valuable energy source and negative environmental effects of accumulated tailings necessitate the recovery of fine coals from these tailings. In the present study, the tailings sample from Tunçbilek Coal Washery of Turkish Coal Enterprise was subjected to oil agglomeration process in order to investigate the possibility of fine coal recovery. Free available waste sunflower oil was extensively used as bridging liquid. Effects of various parameters including solid ratio, oil dosage, agitation rate and time, slurry pH, amount of washing water, particle size, and oil type on deashing and desulphurization were investigated. Optimally, 84.1% of ash and 57.6% of the sulphur was removed from the tailings by combustible recovery of 46.8%. A clean coal with 29.9% ash and 1.3% sulphur was produced from the tailings containing 54.6% ash and 3.0% sulphur. In addition to ash and sulphur analyses, SEM-EDS analysis and polished section examination were also undertaken to reveal the performance of the process.

Effect of a Dispersant Agent in Fine Coal Recovery from Washery Tailings by Oil Agglomeration (Preliminary Study)

Among the fine coal cleaning methods, the oil agglomeration process has important advantages such as high process recovery, more clean product, simple dewatering stage. Several coal agglomeration studies have been undertaken recently and effects of different variables on the process performance have been investigated. However, unlike flotation studies, most of the previous agglomeration studies have not used dispersing agents to minimize slime coating effects of clays. In this study, agglomeration process was applied for recovery of fine coals from coal washery tailings containing remarkable amount of fine coal. Negative effect of fine clays during recovery was tried to be eliminated by using dispersing agent instead of de-sliming. Although ash reductions over 90 % were achieved, performance remained below expectations in terms of combustible matter recovery. However, this study is a preliminary one. It is considered that more satisfied results will be obtained in the next studies by changing the variables such as solid ratio, oil dosage, dispersant type and dosage.

A novel and effective method for removing organic sulfur from low rank coal

The organic sulfur in coal is difficult to remove using gravity separation, oil agglomeration and flotation. Even though chemical leaching/oxidation and bio-desulfurization by bacteria are considered as the efficient methods in organic sulfur removal from low rank coal, these chemical and biological desulfurization technologies are usually difficult to be quickly applied in coal cleaning industry. In this investigation, the reduced iron (Fe) powder, acting as a promoter, was introduced to enhance the desulfurization of low rank coal. Low rank coal was pre-heated with the Fe powder, and then the coal char was forwarded to dry magnetic separation. The organic sulfur in coal could be bonded with Fe and form the Fe-related magnetic compounds which is effectively separated by dry magnetic separator.

Non-polar oil assisted DDA flotation of quartz II: Effect of different polarity oil components on the flotation of quartz

It is well accepted that non-polar oils can be used as collector extender in oil agglomeration flotation of many different types of mineral. In this paper, in order to study the influences of oil structures on the non-polar oil assisted dodecylamine (DDA) flotation of quartz, the research focuses on the interaction of DDA (collector) and non-polar oil (collector extender) in aqueous phase. In this work, saturated hydrocarbon dodecane and cyclohexane, unsaturated hydrocarbon dodecene, aromatic hydrocarbon dimethylbenzene and 1-methylnaphthalene were chosen as researched subjects, and the influences of oil structures on interfacial activity of oil–DDA–water ternary models were investigated by experimental and theoretical methods. The flotation results demonstrated that the collecting capability of the oil and DDA combination follows the order of 1-methylnaphthalene>dimethylbenzene>dodecene>cyclohexane>dodecane. Moreover, molecular dynamic (MD) simulation is performed to investigate the interfacial property of these five non-polar oil-DDA-water systems, and five parameters, radial distribution functions, interaction energy, density distribution, interfacial thickness and self-diffusion coefficient are proposed to reveal the influence mechanism of molecular structure on interfacial activity of the ternary oil-DDA-water systems. The same trends are obtained from the parameters described above, aromatic hydrocarbon dimethylbenzene and 1-methylnaphthalene performance better than saturate hydrocarbon and unsaturated hydrocarbon. The researched results indicate the interaction between non-polar oil and DDA hydrophobic alkyl tail would enhance the mobility of oil component, which induce significant change of interfacial thickness and diffusivity. Additionally, the interaction between DDA hydrophilic head group and water molecules via strong hydrogen bonds, van der Waals interactions and weak electrostatic attraction would lead to water molecules penetrate through DDA monolayer and adsorb on oil surface. The researches enable us to obtain a deeper microscopic-level understanding of the interaction between oil-DDA-water ternary components, and maybe have some references for designing of oil-assisted flotation agent.

Non-polar oil assisted DDA flotation of quartz I: Interfacial interaction between dodecane oil drop and mineral particle

In this paper, in order to study the interaction mechanism of non-polar oil assisted dodecylamine (DDA) flotation of quartz, the particle-oil drops system were treated the same as the hydrophobic particles system. Pure dodecane was chosen as research object, the interfacial interactions between quartz particle and oil drop were investigated through calculation of the extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) potential energy profile. Based on the calculations of the van der Waals attractive interaction potential, hydrophobic interaction potential, hydrocarbon chain association potential, and electrostatic interaction potential, the results indicated that the mineral particle and oil drop attachment state was mainly dominated by hydrophobic interaction potential. In the modification of oil agglomeration flotation process, the adsorption of DDA on the dodecane/water interface presented significant effects on the interfacial interactions between quartz particle and oil drop. It was found that the adsorption of DDA at dodecane/water interface changed the zeta potential value of oil drop from negative to positive. In this case, the attachment of the particles would occur spontaneously, which was due to the contribution of electric double layer attractive interaction. On the contrary, in the traditional oil agglomeration flotation process, a mechanical agitation was required to overcome a potential barrier due to the existence of electric double layer repulsive interaction between the negatively charged oil drops and mineral particles. This study was focus on the theoretical level, and provided some insights into mechanism of oil agglomeration flotation.

Recovery and de-ashing of coal fines from coal water slurry using the oil agglomeration process by waste transformer oil

ABSTRACTThe waste coal water slurry from coal washeries contains a significant amount of energy values in terms of both fine and ultrafine coals. These slurries, when disposed off without proper treatment, pose a threat to the environment. Oil agglomeration can be a promising technique to recover these fine coals. In the present study, waste transformer oil from the power generation-transmission sector was used to recover these coal fines. The effect of pulp density, agglomeration time, oil dosage, and particle size was investigated for the performance of the process. The performance of the process was evaluated based on % ash rejection and % organic matter recovery.

Modeling and optimization of coal oil agglomeration using response surface methodology and artificial neural network approaches

In this study, response surface methodology (RSM) and artificial neural network (ANN) were used to develop an approach to analyze the behavior of different process variables such as pulp density, oil dosage, agglomeration time, and particle size, which affects the coal oil agglomeration process using Linseed oil as a bridging liquid. The investigation was done using Box-Behnken design (BBD) of response surface methodology, the same design of experimental data was used in training with the artificial neural network, and the results obtained from the two methodologies were compared. The ANN model predicted responses with better accuracy with coefficient of determination (R2) 0.97 and 0.95 for % ash rejection and % organic matter recovery respectively in comparison to RSM-BBD R2 of 0.97 and 0.92 for % ash rejection and % organic matter recovery respectively. The optimal condition established for the high % ash rejection and % organic matter recovery were pulp density (3.002%), oil dosage (15%), agglomeration time (15min), particle size (0.168mm) with predicted % ash rejection and % organic matter recovery as 68.00% and 95.24% respectively, with the desirability of 96.90%. The proposed optimal conditions were examined in the laboratory and the % ash rejection and % organic matter recovery achieved as 64.60% and 93.93 respectively.

Central composite design application in oil agglomeration of talc

Central composite design application in oil agglomeration of talc

21.褐炭熱水処理および油水置換の効果 : 褐炭の脱金属,脱炭酸と溶剤スラリー粘度の低減

21.褐炭熱水処理および油水置換の効果 : 褐炭の脱金属,脱炭酸と溶剤スラリー粘度の低減

No.4 植物油凝集法による有機炭素成分回収時の微粉廃棄石炭の粒径や撹拌条件の調査(改質・処理・クリーン化(1))

No.4 植物油凝集法による有機炭素成分回収時の微粉廃棄石炭の粒径や撹拌条件の調査(改質・処理・クリーン化(1))

A hybrid computational intelligence framework in modelling of coal-oil agglomeration phenomenon

The phenomenon of Coal–Oil agglomeration for recovering the coal fines by agitating the coal-water slurries in oil is often practised by coal industry to ensure a safe and healthy environment. Experimental procedure for implementing this phenomenon is complex which involves three main mechanisms: crushing, ultimate and proximate analysis. Past studies have often focused on studying this phenomenon by the application of statistical modelling based on response surface designs. The response surface designs hold an assumption of pre-definition of the model structure, which may introduce uncertainty in the predictive ability of the model. Alternatively, the computational intelligence approach of Genetic programming (GP) that evolves the explicit models automatically can be used. However, the effective functioning of GP is often affected by its nature of producing the models of complex size. Therefore, this work develops a hybrid computational intelligence approach namely, Support vector regression-GP (SVR-GP) to study the coal-oil agglomeration phenomenon. Experimental studies based on five inputs, namely, oil dosage, agitation speed, agglomeration time, temperature, and pH are used to measure the organic matter recovery (OMR (%)) from the coal water slurries. A hybrid computational intelligence approach of SVR-GP is proposed in formulating the relationship between OMR (%) and the five inputs. The performance comparison and validation of the SVR-GP model is done based on the coefficient of determination, root mean square error and mean absolute percentage error. 2-D and 3-D surface analysis based on parametric and sensitivity approach is then conducted on the proposed model to find the relevant relationships between OMR (%) and inputs. The findings suggest that the pH of coal slurry has a significant effect on the OMR (%) and hence is important for reducing coal waste generation and promoting a cleaner environment.

Effect of oil type on the recovery of coal fines from coal waste slurry by the oil agglomeration process

ABSTRACTThe coal fines from slurry waste discarded from the Jamadoba coal preparation plant were used for the recovery of significant energy value coal fines. The effect of oil type was investigated using different oils (edible oil and nonedible oil) at constant pulp density (PD) and agglomeration time (AT) and varying oil dosages. (ODs) The results were evaluated based on % organic matter recovery (% OMR) and % ash rejection (% AR).

A new method for ultra-fast concentration of hydrophobic particles

In froth flotation, fine hydrophobic particles selectively attach to the surface of air bubbles, in turn rising through the liquid and then more slowly as part of the foam that emerges from the system. This paper proposes a paradigm shift from the traditional use of air bubbles as the hydrophobic separation medium to potentially a far more powerful version that utilises a novel hydrophobic binder, a concentrated water in oil emulsion. We show empirically the oil consumption increases linearly with the specific surface area of the particles, with an average oil film thickness of 178nm for fine coal particles, well below the level required for conventional oil agglomeration. The new approach is ultrafast, achieving agglomeration within seconds under batch conditions, with strong selectivity. We also show for the first time continuous steady state agglomeration can be achieved by simply passing the feed and binder suspensions through a partially closed ball valve. Here the residence time through the valve is less than 0.1s. And, by subjecting the agglomerated product to further shear, the emulsion is inverted, releasing bound water. Pressure driven filtration then delivers remarkably low product moistures. Operational aspects of this new technology are discussed.

Recovery of coal fines from coal waste slurry by oil agglomeration process using linseed oil

ABSTRACTThe coal fines from Jamadoba Coal Preparation Plant was used for coal oil agglomeration, and the effect of pulp density (PD), oil dosage (OD), agglomeration time (AT), and particle size (PS) were investigated using linseed oil as bridging liquid. The results were evaluated based on % ash rejection (% AR) and % organic matter recovery (% OMR). The maximum % AR and % OMR were achieved at low PD (3%), high OD (15%), high AT (15 min), and low PS (75 µm).

Statistical Optimization of Coal–Oil Agglomeration Using Response Surface Methodology

ABSTRACTIn this study, a three-level and five-variable Box-Behnken design combined with response surface methodology (RSM) was used to develop an approach to analyze the behavior of different variables of oil agglomeration where pulp density, oil dosage, agglomeration time, particle size, and oil type were varied. The response of coal–oil agglomeration to this variation was investigated using the Box-Behnken design. The efficiency of this process was evaluated by calculating percent ash rejection (%AR) and percent organic-matter recovery (%OMR). The optimal conditions established were pulp density (3%), oil dosage (15%), agglomeration time (15 min), and particle size (0.15 µm) using linseed oil with a predicted %AR and %OMR as 66.02% and 95.93%, respectively, with a desirability of 94.20%. The optimal condition was experimentally validated as 64.60% for ash rejection and 93.94% for organic-matter recovery. The coefficient of determination (R2) was found to be .870 and .926 for %AR and %OMR, respectively.

SOME REMARKS ON ATTACHMENT OF A GAS BUBBLE TO ANOTHER PHASE BOTH IMMERSED IN WATER

In this paper the importance of definition of hydrophobicity and aquaoleophilicity in terms of contact angle as well as the properties of water films in flotation and oil agglomeration were briefly presented. It was shown that the hysteresis of contact angle for a considered system depends on the way of measurement and geometry of the system due to the presence of other that excess pressure and capillary forces and buffering properties of the capillary force. It was suggested that, the measured advancing and receding contact angles should be, when possible, recalculated into the Young (rest, equilibrium) contact angle. It was discussed that quartz is not a good model of hydrophilic surface because its contact angle with a gas phase in water is not zero and that a spontaneous attachment between highly hydrophobic materials such as hydrocarbons and Teflon in dynamic system, such as flotation, does not occur.

Cleaning of High Sulphur Coal by Agglomeration With Waste Vegetable Oil

Laboratory scale agglomeration tests were undertaken to investigate the usability of waste vegetable oil as a bridging liquid in the oil agglomeration for coal cleaning. Waste sunflower oil taken from a university canteen was used as oil in the tests. The effects of the parameters, including coal content, oil content, agitation rate, and agglomeration time on the combustible matter recovery, ash removal, and pyritic sulphur removals, were investigated. It was found that the oil agglomeration process in which waste vegetable oil was used as a bridging liquid succeeded in removal of a considerable amount of ash and pyritic sulphur. Maximum ratios of ash and pyritic sulphur removals were achieved to be 60.63 and 79.09%.

Desulphurizatıon and Deashıng of Fine Coal by Selective Oil Agglomeration Using Waste Motor Oil

Oil agglomeration and enhanced gravity separators are considered to be methods of fine coal cleaning in the future. Although oil agglomeration has benefits, such as high recovery, cleaner product, suitability to oxidized coals, and simple and cheap dewatering stage, it has not been applied in commerecial scale due to oil costs. Use of waste motor oil in the agglomeration instead of original oils can be the solution to this problem. In the present study, fine oxidized coal with a high percent of sulphur was subjected to the agglomeration process by using waste motor oil. The effects of some parameters, including solid concentration, WMO dosage, agglomeration time, stirring speed, coal particle size, pH, and size of recovery sieve, on process performance were investigated. Rejections of ash and pyritic sulphur were obtained to be in the range of 17.94–41.35% and 1.29–36.27%, respectively.

Fuel briquetting using finely disperse waste of coal mining and processing

In focus is fuel briquetting using coal mining and processing waste. The authors present an integrated technology of coal and coke dust processing, including oil agglomeration of input components and fuel briquetting using binder. The optimal binder is chosen to be heavy coal-tar. Influence of a type of compaction and content of different binders on strength of fuel briquettes is analyzed. The quality characteristics of concentrate obtained from dressed coal and coke dust and fuel briquettes made of the concentrate are presented.

Role of recovery sieve size in upgrading of fine coal via oil agglomeration technique

Although recovery sieve size has vital importance for the success of the oil agglomeration technique for upgrading of fine coals, its effect on the process has been generally omitted in previous studies. Therefore, the present study was undertaken to fill the gap in this area and draw attention to the importance of recovery sieve size. An oxidized fine coal sample was subjected to oil agglomeration process and effect of separation sieve size on the success of the process with regard to combustible recovery and ash–sulphur rejection was investigated. 72.90% of ash, 90.90% of pyritic sulphur, and 87.75% of sulphate sulphur were removed from the coal with combustible recovery of 76.53%. Increase in recovery sieve size had positive effect on removals of ash and sulphur. Recovery sieve size was found to be extremely important for the performance of the process in that combustible recovery reduced sharply with increasing sieve sizes. It was concluded that recovery sieve size should be the same size with the top feed size.