Wide-size-range medium-solids are used in a modularized coal beneficiation demonstration system with a gas-solid fluidized bed. The characteristics of fluidization and dry-beneficiation of the medium solids were studi...Wide-size-range medium-solids are used in a modularized coal beneficiation demonstration system with a gas-solid fluidized bed. The characteristics of fluidization and dry-beneficiation of the medium solids were studied. The numerical simulation results show that 0.15–0.06 mm fine magnetite powder can decrease the disturbances caused by the bubbles. This is beneficial to the uniformity of the gas-solid interactions and thus to the uniformity and stability of the bed density and height. The experimental results show that, with an increase in the fine coal content in medium solids, both the fluidization quality and the beneficiation performance of the bed decreased gradually. When the fine coal content was no more than 13%, a relatively high superficial gas velocity increased the beneficiation efficiency. When the content was more than 13%, part of the fine coal was separated, leading to product layers. The separation efficiency was therefore gradually decreased. The models for predicting the bed density standard deviation and the probable error, E, value were both proposed. The E value can reach to 0.04–0.07 g/cm^3 under the optimized experimental parameters. This work provides a foundation for the adjustment of the bed density and the separation performance of the modularized 40–60 ton per hour dry coalbeneficiation industrial system.展开更多
A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide...A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide-size-range magnetite powder （0.3-0.06 ram） and 〈1 mm fine coal were numerically studied. The simulation results show that the fluidization performance of the wide-size-range medium-solid bed is good. The separation performance of the modularized system was then investigated in detail using a mixture of 〈0.3 mm magnetite powder （mass fraction of 0.3-0.06 mm particles is 91.38 %） and 〈1 mm fine coal as solid media. The experimental results show that at separation densities of 1.33 g/cm^3 or 1.61 g/cm^3, 50-6 mm coal can be separated effectively with probable error, E, values of 0.05 g/cm^3 and 0.06 g/cm^3, respectively. This technique is beneficial for saving water resources and for the clean utilization of coal.展开更多
Lignite and sub-bituminous coals from western U.S. contain high amounts of moisture （sub-bituminous： 15%-30%, lignites： 25%-40%）. German and Australian lignites （brown coals） have even higher moisture content, 5...Lignite and sub-bituminous coals from western U.S. contain high amounts of moisture （sub-bituminous： 15%-30%, lignites： 25%-40%）. German and Australian lignites （brown coals） have even higher moisture content, 50% and 60%, respectively. The high moisture content causes a reduction in plant performance and higher emissions, compared to the bituminous （hard） coals. Despite their high-moisture content, lignite and sub-bituminous coals from the western U.S. and worldwide are attractive due to their abundance, low cost, low NOx and SOx emissions, and high reactivity. A novel low-temperature coal drying process employing a fluidized bed dryer and waste heat was developed in the U.S. by a team led by GRE （Great River Energy）. Demonstration of the technology was conducted with the U.S. Department of Energy and GRE funding at Coal Creek Station Unit 1. Following the successful demonstration, the low-temperature coal drying technology was commercialized by GRE under the trade name DryFiningTM fuel enhancement process and implemented at both units at Coal Creek Station. The coal drying system at Coal Creek has been in a continuous commercial operation since December 2009. By implementing DryFining at Coal Creek, GRE avoided $366 million in capital expenditures, which would otherwise be needed to comply with emission regulations. Four years of operating experience is described in this paper.展开更多
Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utiliz...Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed drying can use air of 1.5 times of the minimum fluidizing velocity performance at bubbling fluidized-bed. Experiments have been performed on coal particle sizes of 0.3-1 mm, 1-1.18 mm and 1.18-2.8 mm, with operating temperatures being 100℃, 125℃ and 150℃, respectively. It is found that fluidization has a higher drying rate due to the heat transfer rate through air velocity. Hence, moisture content in lignite can be dried to a desired value with a time interval of 10 rain. The experiment through fluidized-bed reactor is expected to be useful for saving money and time.展开更多
基金financially supported by the National Program on Key Basic Research Project of China (No.2012CB214904)the National Natural Science Foundation of China (Nos.51221462,51134022 and 51174203)
文摘Wide-size-range medium-solids are used in a modularized coal beneficiation demonstration system with a gas-solid fluidized bed. The characteristics of fluidization and dry-beneficiation of the medium solids were studied. The numerical simulation results show that 0.15–0.06 mm fine magnetite powder can decrease the disturbances caused by the bubbles. This is beneficial to the uniformity of the gas-solid interactions and thus to the uniformity and stability of the bed density and height. The experimental results show that, with an increase in the fine coal content in medium solids, both the fluidization quality and the beneficiation performance of the bed decreased gradually. When the fine coal content was no more than 13%, a relatively high superficial gas velocity increased the beneficiation efficiency. When the content was more than 13%, part of the fine coal was separated, leading to product layers. The separation efficiency was therefore gradually decreased. The models for predicting the bed density standard deviation and the probable error, E, value were both proposed. The E value can reach to 0.04–0.07 g/cm^3 under the optimized experimental parameters. This work provides a foundation for the adjustment of the bed density and the separation performance of the modularized 40–60 ton per hour dry coalbeneficiation industrial system.
基金Projects(50921002, 50774084) supported by the National Natural Science Foundation of ChinaProject(2007AA05Z318) supported by the National High-tech Research and Development Program of China+1 种基金Project(BK2010002) supported by the Natural Science Foundation of Jiangsu Province of ChinaProject(20100480473) supported by the China Postdoctoral Science Foundation
文摘A 40-60 t/h modularized dry coal beneficiation process with a novel method to control the bed was designed around a gas-solid fluidized bed separator. Furthermore, the hydrodynamics of medium-solids consisting of wide-size-range magnetite powder （0.3-0.06 ram） and 〈1 mm fine coal were numerically studied. The simulation results show that the fluidization performance of the wide-size-range medium-solid bed is good. The separation performance of the modularized system was then investigated in detail using a mixture of 〈0.3 mm magnetite powder （mass fraction of 0.3-0.06 mm particles is 91.38 %） and 〈1 mm fine coal as solid media. The experimental results show that at separation densities of 1.33 g/cm^3 or 1.61 g/cm^3, 50-6 mm coal can be separated effectively with probable error, E, values of 0.05 g/cm^3 and 0.06 g/cm^3, respectively. This technique is beneficial for saving water resources and for the clean utilization of coal.
文摘Lignite and sub-bituminous coals from western U.S. contain high amounts of moisture （sub-bituminous： 15%-30%, lignites： 25%-40%）. German and Australian lignites （brown coals） have even higher moisture content, 50% and 60%, respectively. The high moisture content causes a reduction in plant performance and higher emissions, compared to the bituminous （hard） coals. Despite their high-moisture content, lignite and sub-bituminous coals from the western U.S. and worldwide are attractive due to their abundance, low cost, low NOx and SOx emissions, and high reactivity. A novel low-temperature coal drying process employing a fluidized bed dryer and waste heat was developed in the U.S. by a team led by GRE （Great River Energy）. Demonstration of the technology was conducted with the U.S. Department of Energy and GRE funding at Coal Creek Station Unit 1. Following the successful demonstration, the low-temperature coal drying technology was commercialized by GRE under the trade name DryFiningTM fuel enhancement process and implemented at both units at Coal Creek Station. The coal drying system at Coal Creek has been in a continuous commercial operation since December 2009. By implementing DryFining at Coal Creek, GRE avoided $366 million in capital expenditures, which would otherwise be needed to comply with emission regulations. Four years of operating experience is described in this paper.
基金supported by the Power Generation & Electricity Delivery of the Korea Institute of Energy Technology Evaluation and Planning (Grant No. NP2008-0092-05) grant funded by the Korea Government Ministry of Knowledge Economy
文摘Lignite is a low rank coal which is evenly distributed throughout the world and accounts for 45% of the total coal reserves. As it has a higher moisture content, its moisture content must be reduced in order to utilize it in power plant. In the present work, experiments on lignite has been done using a lab scale fluidized-bed reactor. Drying lignite through fluidized-bed reactor has a higher drying rate because there is good contact between particles and gas in the fluidized-bed reactor. Fluidized-bed drying can use air of 1.5 times of the minimum fluidizing velocity performance at bubbling fluidized-bed. Experiments have been performed on coal particle sizes of 0.3-1 mm, 1-1.18 mm and 1.18-2.8 mm, with operating temperatures being 100℃, 125℃ and 150℃, respectively. It is found that fluidization has a higher drying rate due to the heat transfer rate through air velocity. Hence, moisture content in lignite can be dried to a desired value with a time interval of 10 rain. The experiment through fluidized-bed reactor is expected to be useful for saving money and time.
