Present investigation focuses on the fractional conversion of low volatile weakly caking coal(LVWC)under the standard set of operating conditions for gasification.For this purpose,samples of LVWC of different ash cont...Present investigation focuses on the fractional conversion of low volatile weakly caking coal(LVWC)under the standard set of operating conditions for gasification.For this purpose,samples of LVWC of different ash content have been collected from Kusunda Area of Bharat Coking Coal Ltd.Gasification results were validated using Homogenous and Shrinking Core kinetic models and the suitability of selected samples for gasification was assessed by estimating the activation energy.The values of activation energy for LVWC samples were obtained in the range of 25.17-44.09 kJ/mol.Further,empirical models were developed to correlate the response of interest with the input variables(temperature,residence time and CO_(2) flow rate).The significance of these developed empirical models was checked using analysis of variance(ANOVA).展开更多
This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acr...This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.展开更多
An open air stockpile of conical shape was formed with 3.5 m base diameter and 5 m height using 500 tons of -200 mm size ROM thermal coal on a concrete floor. Coal sample from the stockpile were collected at 30 days i...An open air stockpile of conical shape was formed with 3.5 m base diameter and 5 m height using 500 tons of -200 mm size ROM thermal coal on a concrete floor. Coal sample from the stockpile were collected at 30 days interval for analysis of various chemical properties like;proximate analysis, ultimate analysis, gross calorific value (GCV) and various combustion related properties such as ignition temperature, peak temperature, burnout temperature, maximum combustion rate, ignition index, burnout index, combustion performance index and combustion rate intensity index. Experimental results show that, due to weathering of coal fixed carbon decreased from 35.6% to 19.9%, elemental carb on (C) decreased from 46.6% to 28.6%, hydrogen (H) decreased from 3.3% to 2.9% and GCV decreased by up to 55% of original value during 330 days of storage of coal in an open atmosphere. Ash con tent of coal increased form 29.2% to 46.6% due to loss of combustibles. Sulfur (S) of coal was found to get increased from 0.33% to 1.08% during storage. The activation energy of coal combustion increased from 22 kJ/mol to 54 kJ/mol. Variation in combustion parameters signifies that weathering has significant negative impact on coal combustion properties as coal become difficult to ignite.展开更多
Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover cl...Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover clean coal with ash content of about 20% with the highest possible yield. Diesel oil as collector and pine oil as frother were used. Box-Behnken statistical design was followed for analyzing the performance at varying pulp density, collector and frother dosage. Results were discussed using 2D surface plots. Response function predictions determined by the regression analysis show coefficient of correlation(R^2) for yield and the ash content as 0.72 and 0.86, respectively. The highest yield of 45.79% is obtained at pulp density 10%, collector dose 2 kg/t and frother dose 1.5 kg/t. The lowest ash content of 18.9% is obtained at pulp density 10%, collector dose 1 kg/t and frother dose 1 kg/t.展开更多
This work presents the analysis of combustion characteristics of high ash Indian coal(28%-40%)collected from different mines of Singaurali coalfield,India.All the coal samples were characterized by proximate and gross...This work presents the analysis of combustion characteristics of high ash Indian coal(28%-40%)collected from different mines of Singaurali coalfield,India.All the coal samples were characterized by proximate and gross calorific value analysis.Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals.Various combustion kinetic parameters such as ignition temperature,peak temperature and burnout temperature,ignition index and burnout index,combustion performance index plus rate and intensity index of combustion process,activation energy were determined to analyse the combustion behaviour of coal.Further all these combustion properties were compared with the volatile matter,ash,fixed carbon and fuel ratio of each coal.Theoretical analysis shows that with increase in ash content,combustion performance initially increases and later descends.Further,coal with(25±1.75)%volatile matter,20%-35%ash and fuel ratio 1.4-1.5 were found to be optimum for coal combustion.展开更多
Beneficiation of coal of -4.76 mm + 3 mm size fraction was investigated in a laboratory model Denver jig.Process variables were studied to analyze their effect on the performance of jig in terms of yield and ash conte...Beneficiation of coal of -4.76 mm + 3 mm size fraction was investigated in a laboratory model Denver jig.Process variables were studied to analyze their effect on the performance of jig in terms of yield and ash content of clean coal. Three-factor three-level Box-Behnken design of experiments with response surface methodology(RSM) was employed to understand the performance behavior of jig. From the study, the bed height was found to be the most significant parameter affecting the yield and ash content of clean coal. It was possible to reduce the ash content from 24.32% in feed to an ash content of 16.55% in clean coal at 2 L/min water flow rate and 10 min jigging time. Influence of operating variables of the jig on responses was presented and discussed in 3D surface plots. The developed model was found to be significant within the range of parameters under investigation with correlation of co-efficient values as 0.99(yield) and 0.98(ash).展开更多
Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable vol...Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion.In the present work,experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal.Heat-affected coal(31%ash and 5300 kcal/kg GCV)collected from Jharia coalfield were blended with thermal coal(28%ash and 5650 kcal/kg GCV)in different ratios of 90:10,80:20,70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities.Burning characteristics of all the coals were carried out using TGA.Various combustion parameters such as ignition temperature,peak temperature,burnout temperature,ignition index,burnout index,combustion performance index,rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process.Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.展开更多
Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alt...Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIR） spectroscopy. A three-layer artificial neural network （ANN） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.展开更多
Numerical methods of a 3D multiphysics,two-phase transport model of proton exchange membrane fuel cell(PEMFC)is studied in this paper.Due to the coexistence of multiphase regions,the standard finite element/finite vol...Numerical methods of a 3D multiphysics,two-phase transport model of proton exchange membrane fuel cell(PEMFC)is studied in this paper.Due to the coexistence of multiphase regions,the standard finite element/finite volume method may fail to obtain a convergent nonlinear iteration for a two-phase transport model of PEMFC[49,50].By introducing Kirchhoff transformation technique and a combined finite element-upwind finite volume approach,we efficiently achieve a fast convergence and reasonable solutions for this multiphase,multiphysics PEMFC model.Numerical implementation is done by using a novel automated finite element/finite volume programgenerator(FEPG).By virtue of a high-level algorithmdescription language(script),component programming and human intelligence technologies,FEPG can quickly generate finite element/finite volume source code for PEMFC simulation.Thus,one can focus on the efficient algorithm research without being distracted by the tedious computer programming on finite element/finite volume methods.Numerical success confirms that FEPG is an efficient tool for both algorithm research and software development of a 3D,multiphysics PEMFC model with multicomponent and multiphase mechanism.展开更多
Oil storage in cavern tank is one of the important ways of oil storage.More than 80%of the oil tanks in the cave storage have been used for around 30 years in China and leakage accidents are likely to occur.When it oc...Oil storage in cavern tank is one of the important ways of oil storage.More than 80%of the oil tanks in the cave storage have been used for around 30 years in China and leakage accidents are likely to occur.When it occurs,the motor closing facilities preventing leakage spreading should be set up.The leaking oil flow characteristic in tunnel must be known for setting up the motor closing facilities.Based on the open-channel unsteady flow theory,a numerical model of tank leakage coupling the oil flow in tunnel was developed,and the characteristic line method was used to solve the model under the given initial condition and boundary condition.The variation of the depth and flow rate with time of oil flowing in the tunnel can be obtained.In order to verify the accuracy of model,the measurement data of high accuracy experimental system for unsteady open-channel flow were conducted to compare with the calculation.It fully confirms the high precision of the numerical model and reflects the variation characteristics of each hydraulic parameter in the numerical model of unsteady open channel flow truly.And then,the leaking oil flow characteristic in tunnel was obtained.It is that the farther from the leaking tank,the lower depth and flow rate of the oil in the tunnel revealed.Furthermore,the effect of the size of oil tank crack on the depth and flow rate was investigated.The greater size of crack makes the oil flow rate higher and the oil deeper in the tunnel and flow faster.展开更多
文摘Present investigation focuses on the fractional conversion of low volatile weakly caking coal(LVWC)under the standard set of operating conditions for gasification.For this purpose,samples of LVWC of different ash content have been collected from Kusunda Area of Bharat Coking Coal Ltd.Gasification results were validated using Homogenous and Shrinking Core kinetic models and the suitability of selected samples for gasification was assessed by estimating the activation energy.The values of activation energy for LVWC samples were obtained in the range of 25.17-44.09 kJ/mol.Further,empirical models were developed to correlate the response of interest with the input variables(temperature,residence time and CO_(2) flow rate).The significance of these developed empirical models was checked using analysis of variance(ANOVA).
基金the National Metallurgical Laboratory,Jamshedpur for their kind support
文摘This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.
文摘An open air stockpile of conical shape was formed with 3.5 m base diameter and 5 m height using 500 tons of -200 mm size ROM thermal coal on a concrete floor. Coal sample from the stockpile were collected at 30 days interval for analysis of various chemical properties like;proximate analysis, ultimate analysis, gross calorific value (GCV) and various combustion related properties such as ignition temperature, peak temperature, burnout temperature, maximum combustion rate, ignition index, burnout index, combustion performance index and combustion rate intensity index. Experimental results show that, due to weathering of coal fixed carbon decreased from 35.6% to 19.9%, elemental carb on (C) decreased from 46.6% to 28.6%, hydrogen (H) decreased from 3.3% to 2.9% and GCV decreased by up to 55% of original value during 330 days of storage of coal in an open atmosphere. Ash con tent of coal increased form 29.2% to 46.6% due to loss of combustibles. Sulfur (S) of coal was found to get increased from 0.33% to 1.08% during storage. The activation energy of coal combustion increased from 22 kJ/mol to 54 kJ/mol. Variation in combustion parameters signifies that weathering has significant negative impact on coal combustion properties as coal become difficult to ignite.
文摘Refuse coal fines of size <500 μm was collected from a metallurgical coal preparation plant located in the eastern coalfield region of India. The coal was beneficiated using froth flotation technique to recover clean coal with ash content of about 20% with the highest possible yield. Diesel oil as collector and pine oil as frother were used. Box-Behnken statistical design was followed for analyzing the performance at varying pulp density, collector and frother dosage. Results were discussed using 2D surface plots. Response function predictions determined by the regression analysis show coefficient of correlation(R^2) for yield and the ash content as 0.72 and 0.86, respectively. The highest yield of 45.79% is obtained at pulp density 10%, collector dose 2 kg/t and frother dose 1.5 kg/t. The lowest ash content of 18.9% is obtained at pulp density 10%, collector dose 1 kg/t and frother dose 1 kg/t.
文摘This work presents the analysis of combustion characteristics of high ash Indian coal(28%-40%)collected from different mines of Singaurali coalfield,India.All the coal samples were characterized by proximate and gross calorific value analysis.Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals.Various combustion kinetic parameters such as ignition temperature,peak temperature and burnout temperature,ignition index and burnout index,combustion performance index plus rate and intensity index of combustion process,activation energy were determined to analyse the combustion behaviour of coal.Further all these combustion properties were compared with the volatile matter,ash,fixed carbon and fuel ratio of each coal.Theoretical analysis shows that with increase in ash content,combustion performance initially increases and later descends.Further,coal with(25±1.75)%volatile matter,20%-35%ash and fuel ratio 1.4-1.5 were found to be optimum for coal combustion.
文摘Beneficiation of coal of -4.76 mm + 3 mm size fraction was investigated in a laboratory model Denver jig.Process variables were studied to analyze their effect on the performance of jig in terms of yield and ash content of clean coal. Three-factor three-level Box-Behnken design of experiments with response surface methodology(RSM) was employed to understand the performance behavior of jig. From the study, the bed height was found to be the most significant parameter affecting the yield and ash content of clean coal. It was possible to reduce the ash content from 24.32% in feed to an ash content of 16.55% in clean coal at 2 L/min water flow rate and 10 min jigging time. Influence of operating variables of the jig on responses was presented and discussed in 3D surface plots. The developed model was found to be significant within the range of parameters under investigation with correlation of co-efficient values as 0.99(yield) and 0.98(ash).
文摘Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields,India.Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion.In the present work,experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal.Heat-affected coal(31%ash and 5300 kcal/kg GCV)collected from Jharia coalfield were blended with thermal coal(28%ash and 5650 kcal/kg GCV)in different ratios of 90:10,80:20,70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities.Burning characteristics of all the coals were carried out using TGA.Various combustion parameters such as ignition temperature,peak temperature,burnout temperature,ignition index,burnout index,combustion performance index,rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process.Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.
基金the funding given by Council of Scientific and Industrial Research(CSIR)India through project NWP-31 for this project
文摘Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIR） spectroscopy. A three-layer artificial neural network （ANN） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.
基金supported by NSF Grant DMS-0913757 and 111-Program for energysaving and environment-friendly automobile(B08019)of ChinaPengtao Sun was also partially supported by State Key Laboratory of Scientific and Engineering Computing,Chinese Academy of Sciences during his visit in July,2010.Su Zhou is supported by 863 Program(2008AA050403)+2 种基金Shanghai Pujiang Talent Plan(08PJ1409)of China.Qiya Hu is supported by The Key Project of Natural Science Foundation of China G11031006National Basic Research Programof China G2011309702Natural Science Foundation of China G10771178.
文摘Numerical methods of a 3D multiphysics,two-phase transport model of proton exchange membrane fuel cell(PEMFC)is studied in this paper.Due to the coexistence of multiphase regions,the standard finite element/finite volume method may fail to obtain a convergent nonlinear iteration for a two-phase transport model of PEMFC[49,50].By introducing Kirchhoff transformation technique and a combined finite element-upwind finite volume approach,we efficiently achieve a fast convergence and reasonable solutions for this multiphase,multiphysics PEMFC model.Numerical implementation is done by using a novel automated finite element/finite volume programgenerator(FEPG).By virtue of a high-level algorithmdescription language(script),component programming and human intelligence technologies,FEPG can quickly generate finite element/finite volume source code for PEMFC simulation.Thus,one can focus on the efficient algorithm research without being distracted by the tedious computer programming on finite element/finite volume methods.Numerical success confirms that FEPG is an efficient tool for both algorithm research and software development of a 3D,multiphysics PEMFC model with multicomponent and multiphase mechanism.
基金by Natural Science Foundation of Chongqing(cstc2019jcyj-msxmX0268,cstc2019jcyjmsxmX0286 and cstc2019jcyj-msxmX0628).
文摘Oil storage in cavern tank is one of the important ways of oil storage.More than 80%of the oil tanks in the cave storage have been used for around 30 years in China and leakage accidents are likely to occur.When it occurs,the motor closing facilities preventing leakage spreading should be set up.The leaking oil flow characteristic in tunnel must be known for setting up the motor closing facilities.Based on the open-channel unsteady flow theory,a numerical model of tank leakage coupling the oil flow in tunnel was developed,and the characteristic line method was used to solve the model under the given initial condition and boundary condition.The variation of the depth and flow rate with time of oil flowing in the tunnel can be obtained.In order to verify the accuracy of model,the measurement data of high accuracy experimental system for unsteady open-channel flow were conducted to compare with the calculation.It fully confirms the high precision of the numerical model and reflects the variation characteristics of each hydraulic parameter in the numerical model of unsteady open channel flow truly.And then,the leaking oil flow characteristic in tunnel was obtained.It is that the farther from the leaking tank,the lower depth and flow rate of the oil in the tunnel revealed.Furthermore,the effect of the size of oil tank crack on the depth and flow rate was investigated.The greater size of crack makes the oil flow rate higher and the oil deeper in the tunnel and flow faster.
