CAJ | 학술논문

采用κ-ε模型和组分输运方程进行数值模拟,考察了重油催化工业沉降器抑制结焦改造后其沉降空间的稳态流场及油气分率.结果表明,改造后的沉降器空间油气以顶部下行、底部上行略带扭摆的纵向流动为主,顶部油气下行速度小于0.15 m/s,底部油气上行速度平均为0.5 m/s,纵向流速比横向流速高1～2个数量级.中心抽吸管口区域存在较强的油气汇聚,速度10 m/s左右.改造后的沉降空间不存在流动死区,绝大部分油气能迅速从中心抽吸管排出沉降器,只有低于10%的油气不能迅速排出沉降器,停留时间稍长.沉降器下部油气摩尔分率较大(平均约50%,顶部低于25%,部分区域甚至小于10%).改造后沉降器空间的结焦大大减轻.
채용κ-ε모형화조분수운방정진행수치모의,고찰료중유최화공업침강기억제결초개조후기침강공간적은태류장급유기분솔.결과표명,개조후적침강기공간유기이정부하행、저부상행략대뉴파적종향류동위주,정부유기하행속도소우0.15 m/s,저부유기상행속도평균위0.5 m/s,종향류속비횡향류속고1～2개수량급.중심추흡관구구역존재교강적유기회취,속도10 m/s좌우.개조후적침강공간불존재류동사구,절대부분유기능신속종중심추흡관배출침강기,지유저우10%적유기불능신속배출침강기,정류시간초장.침강기하부유기마이분솔교대(평균약50%,정부저우25%,부분구역심지소우10%).개조후침강기공간적결초대대감경.
The gas flow field distribution and the molar fraction distribution of oil gas in the RFCC disengager after anti-coke deposition retrofitting were simulated by using k-t model and species transport equation.Results indicated that the oil gas flow field was not symmetrical and the lengthways velocity was 10 or 10~2 times larger than the transverse velocity.Gas in the upper space of the disengager flowed downwards with the velocity less than 0.15 m/s and the upward stream existed in the lower part with the velocity about 0.5 m/s.Near the center of the disengager gas pooled towards the nozzle of plenum tube with its velocity of 10 m/s.There were no stagnant regions for gas current and most of it was pumped out of the disengager quickly except for a small portion, which only took 10% mass fraction of all the oil gas with some what longer residence time correspondingly.The average molar fraction of oil gas was 50% at the bottom of the disengager and less than 25% in the upper place, even less than 10% in some areas.Total coke deposition in the disengager was reduced after anti-coke amelioration.