Bubble dispersion greatly relies on spargers. Single or ifice and porous spargers were tested inside a bubble column under a low gas thr oughput to study their influences on gas dispersion and gas-liquid interface ar ...Bubble dispersion greatly relies on spargers. Single or ifice and porous spargers were tested inside a bubble column under a low gas thr oughput to study their influences on gas dispersion and gas-liquid interface ar ea. A PBE model without considering the effect of bubble coalescence was develo ped to describe axial bubble distribution. Both simulation and experimental res ults showed that bubbles broke up much faster than coalesced under low gas veloc ity. For a single orifice sparger, breakage was a dominant feature for bubbles after they left the orifice. Initial bubbles formed over the orifice were mostl y larger than the largest stable bubble. They broke up quickly and their sizes were reduced below the maximum diameter d_s of stable bubbles. In contrast , a porous sparger produced a large amount of initial bubbles smaller than the l argest stable bubble. The bubbles possessed smaller size and narrower distribut ion compared with the bubbles obtained by single orifice spargers. With the por ous sparger, gas-liquid surface area was increased by 5—6 times even though th e gas holdup changed insignificantly. High mass transfer area could be obtained by injecting more small initial bubbles with diameters under d_s.展开更多
在直径为48 mm 的鼓泡塔反应器中,模拟工业条件研究了氧气分压对甲苯液相催化氧化生成苯甲酸反应的影响。结果表明,甲苯液相催化氧化反应在低氧气分压下对氧气是1级反应,随氧气分压增加,氧气的影响逐渐减弱,在高氧气分压区过渡为对氧气...在直径为48 mm 的鼓泡塔反应器中,模拟工业条件研究了氧气分压对甲苯液相催化氧化生成苯甲酸反应的影响。结果表明,甲苯液相催化氧化反应在低氧气分压下对氧气是1级反应,随氧气分压增加,氧气的影响逐渐减弱,在高氧气分压区过渡为对氧气是0级反应.根据甲苯氧化的自由基链式反应机理,推导出了覆盖整个氧气浓度区的动力学方程,不仅可以很好地解释在不同氧气分压区氧气级数变化的现象,而且对反应过程的描述具有很高的计算精度,在145℃和155℃反应温度下的计算误差小于4%。展开更多
文摘Bubble dispersion greatly relies on spargers. Single or ifice and porous spargers were tested inside a bubble column under a low gas thr oughput to study their influences on gas dispersion and gas-liquid interface ar ea. A PBE model without considering the effect of bubble coalescence was develo ped to describe axial bubble distribution. Both simulation and experimental res ults showed that bubbles broke up much faster than coalesced under low gas veloc ity. For a single orifice sparger, breakage was a dominant feature for bubbles after they left the orifice. Initial bubbles formed over the orifice were mostl y larger than the largest stable bubble. They broke up quickly and their sizes were reduced below the maximum diameter d_s of stable bubbles. In contrast , a porous sparger produced a large amount of initial bubbles smaller than the l argest stable bubble. The bubbles possessed smaller size and narrower distribut ion compared with the bubbles obtained by single orifice spargers. With the por ous sparger, gas-liquid surface area was increased by 5—6 times even though th e gas holdup changed insignificantly. High mass transfer area could be obtained by injecting more small initial bubbles with diameters under d_s.
文摘在直径为48 mm 的鼓泡塔反应器中,模拟工业条件研究了氧气分压对甲苯液相催化氧化生成苯甲酸反应的影响。结果表明,甲苯液相催化氧化反应在低氧气分压下对氧气是1级反应,随氧气分压增加,氧气的影响逐渐减弱,在高氧气分压区过渡为对氧气是0级反应.根据甲苯氧化的自由基链式反应机理,推导出了覆盖整个氧气浓度区的动力学方程,不仅可以很好地解释在不同氧气分压区氧气级数变化的现象,而且对反应过程的描述具有很高的计算精度,在145℃和155℃反应温度下的计算误差小于4%。
