Hardgrove grindability index （HGI） is an important indicator of coal grindability, and is one of the most important parameters to determine the capacity of coal pulverizer in power station. However, HGI is an empiri...Hardgrove grindability index （HGI） is an important indicator of coal grindability, and is one of the most important parameters to determine the capacity of coal pulverizer in power station. However, HGI is an empirical grindability index without linkages to any known physical parameters. To investigate the effect of energy input on the grinding in Hardgrove mill. a T20WN torque meter was installed on the shaft of a modified Hardgrove mill to record the torque driving the mill. Samples from four kinds of coals with HGI ranging from 36 to 72 were prepared according to the procedure of standard HGI test and ground in a modified Hardgrove mill at different revolutions. The relation of sample size reduction degree to specific comminution energy （Ecs） was studied with Shi-Kojovic model, The results show that Shi-Kojovic model predicted well the coal size reduction degree with Ecs in Hardgrove mill. The griadability index given by Shi-Kojovic model has a similar trend with HGI. The relation of sample size reduction degree to Ecs reveals that HGI has a non-linear relationship with effective specific energy in Hardgrove mill, which explains the non-linear relation of HG1 to industrial pulverizer capacity.展开更多
Pulsed electric field is an innovative method for non-thermal food processing. The effects of pulsed electric field on cell disintegration and mass transfer in sugar beet were studied. Sugar beet slices were treated b...Pulsed electric field is an innovative method for non-thermal food processing. The effects of pulsed electric field on cell disintegration and mass transfer in sugar beet were studied. Sugar beet slices were treated by various Field strengths （0.5-6 kV cm^-1）, capacity of capacitors （0.5, 8 and 32 μF） and pulse numbers （1-100 pulses）. The cell disintegration index and energy input for each treated sample was evaluated. The results showed that the cell membrane of PEF （Pulsed Electric Field） treated samples using 2 kV cm^-1, 8 μF after 20 pulses, and 3 kV cm1, 8 μF after 10 pulses were rapidly disintegrated in less than 1 min. Most important parameters during cell permeabilization were the total energy input followed by field strength. Energy efficiency index was defined as cell disintegration index per energy input unit. The maximum efficiency index was achieved using 2 kV cm^-1, 8 μF after 5 pulses. Comparison between PEF pretreatment and thermal method showed that large amount of sugar may be extracted after PEF pretreatment using field strength of 2 Kv cm^-1, 8μF in less than 10 min at ambient temperature. In.addition, the consumed energy for thermal treatment was approximately 20 to 50 times more than PEF pretreatment. Optimizing the field conditions in PEF treatment is an important factor to achieve high amount of sugar extraction from sugar beet.展开更多
基金the financial supports provided by the National Key Basic Research and Development Program of China (No. 2012CB214904)the Coal Joint Fund of the National Natural Science Foundation of China and Shenhua Group (No. 51134022)+2 种基金the Creative Scholars Climbing Program of Jiangsu Province Basic Research Program (No. BK2010002)the Funds for Creative Research Groups of China (No. 50921002)the Australia Coal Association Research Program (No. C15079)
文摘Hardgrove grindability index （HGI） is an important indicator of coal grindability, and is one of the most important parameters to determine the capacity of coal pulverizer in power station. However, HGI is an empirical grindability index without linkages to any known physical parameters. To investigate the effect of energy input on the grinding in Hardgrove mill. a T20WN torque meter was installed on the shaft of a modified Hardgrove mill to record the torque driving the mill. Samples from four kinds of coals with HGI ranging from 36 to 72 were prepared according to the procedure of standard HGI test and ground in a modified Hardgrove mill at different revolutions. The relation of sample size reduction degree to specific comminution energy （Ecs） was studied with Shi-Kojovic model, The results show that Shi-Kojovic model predicted well the coal size reduction degree with Ecs in Hardgrove mill. The griadability index given by Shi-Kojovic model has a similar trend with HGI. The relation of sample size reduction degree to Ecs reveals that HGI has a non-linear relationship with effective specific energy in Hardgrove mill, which explains the non-linear relation of HG1 to industrial pulverizer capacity.
文摘Pulsed electric field is an innovative method for non-thermal food processing. The effects of pulsed electric field on cell disintegration and mass transfer in sugar beet were studied. Sugar beet slices were treated by various Field strengths （0.5-6 kV cm^-1）, capacity of capacitors （0.5, 8 and 32 μF） and pulse numbers （1-100 pulses）. The cell disintegration index and energy input for each treated sample was evaluated. The results showed that the cell membrane of PEF （Pulsed Electric Field） treated samples using 2 kV cm^-1, 8 μF after 20 pulses, and 3 kV cm1, 8 μF after 10 pulses were rapidly disintegrated in less than 1 min. Most important parameters during cell permeabilization were the total energy input followed by field strength. Energy efficiency index was defined as cell disintegration index per energy input unit. The maximum efficiency index was achieved using 2 kV cm^-1, 8 μF after 5 pulses. Comparison between PEF pretreatment and thermal method showed that large amount of sugar may be extracted after PEF pretreatment using field strength of 2 Kv cm^-1, 8μF in less than 10 min at ambient temperature. In.addition, the consumed energy for thermal treatment was approximately 20 to 50 times more than PEF pretreatment. Optimizing the field conditions in PEF treatment is an important factor to achieve high amount of sugar extraction from sugar beet.
