化工学报 ›› 2022, Vol. 73 ›› Issue (1): 266-274.DOI: 10.11949/0438-1157.20211431
翁俊旗1(),刘鑫磊1,余佳豪1,施尧1,叶光华1(),屈进2(),段学志1,李金兵2,周兴贵1
收稿日期:
2021-10-08
修回日期:
2021-12-20
出版日期:
2022-01-05
发布日期:
2022-01-18
通讯作者:
叶光华,屈进
作者简介:
翁俊旗(1998—),男,硕士研究生,基金资助:
Junqi WENG1(),Xinlei LIU1,Jiahao YU1,Yao SHI1,Guanghua YE1(),Jin QU2(),Xuezhi DUAN1,Jinbing LI2,Xinggui ZHOU1
Received:
2021-10-08
Revised:
2021-12-20
Online:
2022-01-05
Published:
2022-01-18
Contact:
Guanghua YE,Jin QU
摘要:
压降是衡量固定床反应器优劣的重要指标,直接影响了反应性能和综合能耗,催化剂颗粒的外形和尺寸是影响固定床反应器压降的关键因素。采用颗粒分辨计算流体力学模型,研究了工业上常用的蜂窝状催化剂颗粒上中空结构对固定床反应器压降的影响规律。首先,通过对比实验测量的催化剂床层空隙率和压降,验证了建立的颗粒分辨计算流体力学模型的合理性和准确性,其中模型计算获得的压降与实验值相差5%以内。接着,研究了蜂窝状催化剂颗粒开孔个数的影响,发现在催化剂颗粒体积和开孔体积相同的情况下,开孔个数不会显著影响催化剂床层的空隙率,但开孔个数增加会导致压降增大,这主要是由于孔径变小后增大了流体在孔内的动量损失。最后,考察了单孔柱催化剂颗粒尺寸的影响,发现可通过调变外圆柱半径、内孔半径和高度,进而大幅度改变催化剂床层空隙率和压降,当单孔柱壁面越薄时,空隙率越大,致使压降越低。研究结果可以为催化剂颗粒外形的优化设计提供强大的模型工具和一定的理论指导。
中图分类号:
翁俊旗, 刘鑫磊, 余佳豪, 施尧, 叶光华, 屈进, 段学志, 李金兵, 周兴贵. 蜂窝状催化剂中空结构对固定床反应器压降的影响[J]. 化工学报, 2022, 73(1): 266-274.
Junqi WENG, Xinlei LIU, Jiahao YU, Yao SHI, Guanghua YE, Jin QU, Xuezhi DUAN, Jinbing LI, Xinggui ZHOU. Influence of hollow structure of honeycomb catalysts on the pressure drop in packed bed reactors[J]. CIESC Journal, 2022, 73(1): 266-274.
参数 | 数值 |
---|---|
进口温度Tin | 220℃ |
出口压力Pout | 10 atm(1 atm=101325 Pa) |
进口流速uin | 1 m/s |
进口氧气摩尔分数XO | 8% |
进口乙烯摩尔分数XC | 36% |
进口氮气摩尔分数XN | 44% |
进口二氧化碳摩尔分数XCO | 12% |
反应管内径D | 35 mm |
黏度μ | 2.26×10-5 Pa?s |
密度ρ | 6.41 kg/m3 |
表1 流动模拟所用的边界条件及模型参数
Table 1 Boundary conditions and model parameters for flow simulations
参数 | 数值 |
---|---|
进口温度Tin | 220℃ |
出口压力Pout | 10 atm(1 atm=101325 Pa) |
进口流速uin | 1 m/s |
进口氧气摩尔分数XO | 8% |
进口乙烯摩尔分数XC | 36% |
进口氮气摩尔分数XN | 44% |
进口二氧化碳摩尔分数XCO | 12% |
反应管内径D | 35 mm |
黏度μ | 2.26×10-5 Pa?s |
密度ρ | 6.41 kg/m3 |
图5 单孔柱和七孔柱催化剂颗粒在床层中的角度分布和径向空隙率分布
Fig.5 Angle distributions and radial voidage distributions of Raschig ring and seven-hole cylinder catalyst pellets in the packed bed
图6 单孔柱和七孔柱催化剂颗粒床层中流速分布和压力分布的截面图
Fig.6 Contours of flow rate and pressure in the beds packed with Raschig ring and seven-hole cylinder catalyst pellets
外形 | 平均空隙率 | 压降(ΔP/L)/(Pa/m) | 表观反应速率/(mol/(m3·s) |
---|---|---|---|
单孔柱 | 0.582 | 3660 | 5.56 |
七孔柱 | 0.579 | 3982 | 7.73 |
表2 单孔柱和七孔柱催化剂颗粒堆积床层的空隙率、压降和表观反应速率
Table 2 Voidages, pressure drops, and apparent reaction rates of catalyst in the beds packed with Raschig ring and seven-hole cylinder catalyst pellets
外形 | 平均空隙率 | 压降(ΔP/L)/(Pa/m) | 表观反应速率/(mol/(m3·s) |
---|---|---|---|
单孔柱 | 0.582 | 3660 | 5.56 |
七孔柱 | 0.579 | 3982 | 7.73 |
图7 单孔柱和七孔柱催化剂颗粒床层中温度分布和乙烯浓度分布的截面图
Fig.7 Contours of temperature and C2H4 concentration in the beds packed with Raschig ring and seven-hole cylinder catalyst pellets
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
3.86 | 1.56 | 5.60 | 0.514 | 4501 |
3.86 | 1.81 | 6.00 | 0.545 | 4320 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
3.86 | 2.15 | 6.80 | 0.599 | 3226 |
3.86 | 2.28 | 7.20 | 0.634 | 2802 |
表3 单孔柱催化剂外形尺寸以及相应床层空隙率和压降(R不变,变化r和H)
Table 3 Dimensions of Raschig rings, as well as the voidages and pressure drops of their corresponding beds (R unchanged, but r and H varied)
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
3.86 | 1.56 | 5.60 | 0.514 | 4501 |
3.86 | 1.81 | 6.00 | 0.545 | 4320 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
3.86 | 2.15 | 6.80 | 0.599 | 3226 |
3.86 | 2.28 | 7.20 | 0.634 | 2802 |
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
5.09 | 2.00 | 3.20 | 0.524 | 4492 |
4.31 | 2.00 | 4.80 | 0.569 | 4002 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
3.57 | 2.00 | 8.00 | 0.622 | 3500 |
3.36 | 2.00 | 9.60 | 0.643 | 3188 |
表4 单孔柱催化剂外形尺寸以及相应床层空隙率和压降(r不变,变化R和H)
Table 4 Dimensions of Raschig rings, as well as the voidages and pressure drops of their corresponding beds (r unchanged, but R and H varied)
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
5.09 | 2.00 | 3.20 | 0.524 | 4492 |
4.31 | 2.00 | 4.80 | 0.569 | 4002 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
3.57 | 2.00 | 8.00 | 0.622 | 3500 |
3.36 | 2.00 | 9.60 | 0.643 | 3188 |
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
3.46 | 1.00 | 6.40 | 0.461 | 5927 |
3.63 | 1.50 | 6.40 | 0.516 | 4728 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
4.15 | 2.50 | 6.40 | 0.642 | 3199 |
4.46 | 3.00 | 6.40 | 0.699 | 2188 |
表5 单孔柱催化剂外形尺寸以及相应床层空隙率和压降(H不变,变化R和r)
Table 5 Dimensions of Raschig rings, as well as the voidages and pressure drops of their corresponding beds (H unchanged, but R and r varied)
外径R/mm | 内径r/mm | 高度H/mm | 平均空隙率 | 压降(ΔP/L)/(Pa/m) |
---|---|---|---|---|
3.46 | 1.00 | 6.40 | 0.461 | 5927 |
3.63 | 1.50 | 6.40 | 0.516 | 4728 |
3.86 | 2.00 | 6.40 | 0.582 | 3660 |
4.15 | 2.50 | 6.40 | 0.642 | 3199 |
4.46 | 3.00 | 6.40 | 0.699 | 2188 |
图8 单孔柱催化剂颗粒床层的压降和空隙率(R不变,变化r和H)
Fig.8 Pressure drops and voidages of the beds packed with Raschig ring catalyst pellets (R unchanged, but r and H varied)
图9 单孔柱催化剂颗粒床层的压降和空隙率(r不变,变化R和H)
Fig.9 Pressure drops and voidages of the beds packed with Raschig ring catalyst pellets (r unchanged, but R and H varied)
图10 单孔柱催化剂颗粒床层的压降和空隙率(H不变,变化R和r)
Fig.10 Pressure drops and voidages of the beds packed with Raschig ring catalyst pellets (H unchanged, but R and r varied)
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