An experimental study of vertical gas conveying of Geldart-D powder as a dilute phase is performed in a pipe of length 22m and internal diameter 0.05m using a fluidized blow tank at gas velocity ranging from 5m.S-1 to...An experimental study of vertical gas conveying of Geldart-D powder as a dilute phase is performed in a pipe of length 22m and internal diameter 0.05m using a fluidized blow tank at gas velocity ranging from 5m.S-1 to 13m.s-1 and loading ratio up to about 30. The characteristics of gas conveying, such as pressure drop, the choking velocity and the minimum primary velocity of the fluidized blow tank, are discussed in detail.展开更多
Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic ...Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.展开更多
Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can...Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can only be achieved, if the pellets remain intact until they are ingested by the birds. Many factors may affect pellet physical quality, such as feed nutritional composition, ingredient particle size, conditioning temperature and time, feed moisture, etc.. Despite their importance, sometimes these factors are not managed properly, therefore, pelleted feed may not contain a high amount of intact pellets. In addition, the possible interactions among these variables may yield different responses in comparison with those expected when individual factors are considered. Very few experiments have been conducted to evaluate the impact of combined factors on pellet quality. This may be explained by the presence of many qualitative and quantitative factors in the manufacturing process. Research indicates that heat processing and feed formulation, especially fat inclusion level, are the factors which have the biggest influence on pellet quality. Strategies, such as the expansion process and fat inclusion restriction or post pellet liquid fat application could be implemented to produce high physical quality pellets. More research is needed to identify which factors have a positive or negative effect on pelleting process and to find new strategies to improve pellet physical quality.展开更多
文摘An experimental study of vertical gas conveying of Geldart-D powder as a dilute phase is performed in a pipe of length 22m and internal diameter 0.05m using a fluidized blow tank at gas velocity ranging from 5m.S-1 to 13m.s-1 and loading ratio up to about 30. The characteristics of gas conveying, such as pressure drop, the choking velocity and the minimum primary velocity of the fluidized blow tank, are discussed in detail.
基金Supported by National Science Foundation of USA(CMMI-0970112)
文摘Biofuels produced from cellulosic biomass can be used to replace petroleum-based transportation fuels. However, the manufacturing cost of cellulosic biofuels is still high, partly due to the low density of cellulosic feed-stocks. Pelleting of cellulosic feedstocks can increase their density, making their transportation and storage as well as biofuel conversion more efficient and, therefore, reducing the overall cost of biofuel manufacturing. It has been shown that ultrasonic-vibration-assisted (UV-A) pelleting, without using high-temperature steam and binder materials, can produce pellets with density comparable to that produced by conventional pelleting methods. Furthermore, the sugar yield of biomass (wheat straw) processed with UV-A pelleting is 20% higher than that of biomass pelleted without ultrasonic vibration. This paper reports an experimental investigation of UV-A pelleting of switchgrass. The influences of ultrasonic vibration on pellet density, stability, durability, and pelleting force are discussed. It is concluded that pellets processed with ultrasonic vibration had higher density and stability than those processed without ultrasonic vibration, they were more durable than those processed without ultrasonic vibration, and pelleting force with ultrasonic vibration was lower than that without ultrasonic vibration.
文摘Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can only be achieved, if the pellets remain intact until they are ingested by the birds. Many factors may affect pellet physical quality, such as feed nutritional composition, ingredient particle size, conditioning temperature and time, feed moisture, etc.. Despite their importance, sometimes these factors are not managed properly, therefore, pelleted feed may not contain a high amount of intact pellets. In addition, the possible interactions among these variables may yield different responses in comparison with those expected when individual factors are considered. Very few experiments have been conducted to evaluate the impact of combined factors on pellet quality. This may be explained by the presence of many qualitative and quantitative factors in the manufacturing process. Research indicates that heat processing and feed formulation, especially fat inclusion level, are the factors which have the biggest influence on pellet quality. Strategies, such as the expansion process and fat inclusion restriction or post pellet liquid fat application could be implemented to produce high physical quality pellets. More research is needed to identify which factors have a positive or negative effect on pelleting process and to find new strategies to improve pellet physical quality.
