化学反应工程与工艺
化學反應工程與工藝
화학반응공정여공예
CHEMICAL REACTION ENGINEERING AND TECHNOLOGY
2014年
1期
71-78
,共8页
陈昇%王维%闫子涵%卢春喜%范怡平
陳昇%王維%閆子涵%盧春喜%範怡平
진승%왕유%염자함%로춘희%범이평
催化裂化%进料段%喷嘴%提升管反应器%曳力模型%计算流体力学
催化裂化%進料段%噴嘴%提升管反應器%抴力模型%計算流體力學
최화열화%진료단%분취%제승관반응기%예력모형%계산류체역학
fluid catalytic cracking%feedstock injection structure%nozzle%riser reactor%drag model%computational fluid dynamics
提升管进料混合段是催化裂化提升管反应器最关键的区域。为找到一种合理的方法以改善提升管进料段内油剂两相流动及混合状况,采用了 EMMS 曳力模型,对提升管进料混合段气固两相流混合及流动进行三维计算流体力学(CFD)模拟,并与实验数据进行了对比;分析了气固两相流动及混合特性,还模拟分析了不同进料角度对提升管进料混合段内二次流的影响以及两相流动、混合状况。结果表明,EMMS/Matrix曳力模型能够较为准确地模拟进料混合段内气固两相流动、混合过程;当喷嘴斜向上喷射进料时,射流影响区颗粒流混合不均匀,颗粒流恢复稳定流型所需时间长,且边壁受二次流影响,出现“高浓度、高返混”区域,工业过程中易引起结焦。由此提出了一种新型提升管进料段结构的改进方案,能合理利用二次流,实现颗粒流均匀混合和流动。
提升管進料混閤段是催化裂化提升管反應器最關鍵的區域。為找到一種閤理的方法以改善提升管進料段內油劑兩相流動及混閤狀況,採用瞭 EMMS 抴力模型,對提升管進料混閤段氣固兩相流混閤及流動進行三維計算流體力學(CFD)模擬,併與實驗數據進行瞭對比;分析瞭氣固兩相流動及混閤特性,還模擬分析瞭不同進料角度對提升管進料混閤段內二次流的影響以及兩相流動、混閤狀況。結果錶明,EMMS/Matrix抴力模型能夠較為準確地模擬進料混閤段內氣固兩相流動、混閤過程;噹噴嘴斜嚮上噴射進料時,射流影響區顆粒流混閤不均勻,顆粒流恢複穩定流型所需時間長,且邊壁受二次流影響,齣現“高濃度、高返混”區域,工業過程中易引起結焦。由此提齣瞭一種新型提升管進料段結構的改進方案,能閤理利用二次流,實現顆粒流均勻混閤和流動。
제승관진료혼합단시최화열화제승관반응기최관건적구역。위조도일충합리적방법이개선제승관진료단내유제량상류동급혼합상황,채용료 EMMS 예력모형,대제승관진료혼합단기고량상류혼합급류동진행삼유계산류체역학(CFD)모의,병여실험수거진행료대비;분석료기고량상류동급혼합특성,환모의분석료불동진료각도대제승관진료혼합단내이차류적영향이급량상류동、혼합상황。결과표명,EMMS/Matrix예력모형능구교위준학지모의진료혼합단내기고량상류동、혼합과정;당분취사향상분사진료시,사류영향구과립류혼합불균균,과립류회복은정류형소수시간장,차변벽수이차류영향,출현“고농도、고반혼”구역,공업과정중역인기결초。유차제출료일충신형제승관진료단결구적개진방안,능합리이용이차류,실현과립류균균혼합화류동。
Feedstock injection zone is the most critical area for fluid catalytic cracking (FCC) riser reactor. The 3-D computational fluid dynamics (CFD) simulation of gas-solid two-phase mixing and flow in this zone was performed by an energy-minimization multi-scale (EMMS) drag model. The dynamic behavior of the mixing and flow was discussed by comparing the simulation results with experimental data. Moreover, the two-phase mixing and flow in different feedstock injection structures with various angles of feedstock nozzles relative to the axes of riser reactor were simulated. The gas-solid inhomogeneous mixing and the secondary flow were analyzed. The results show that the behaviors of gas-solid two-phase mixing and flow in the feedstock injection zone can be depicted well by the EMMS drag model. Furthermore, when the angles of the feedstock jet up to the riser, it will be appeared that the gas-solid two-phase mixing sufficiently require more time to reach the steady flow. The cluster together and back mixing of a large number of particles in the vicinity of riser wall are inevitable, which results in the coke in industry. Finally, a novel way is proposed to realize gas-solid two-phase uniform mixing and flow as well as to control the secondary flow reasonably.