Fundamental study on flow and reaction performance of isobutane alkylation catalyzed by ionic liquid in microreactor

doi:10.11949/0438-1157.20210935

Abstract

Abstract:

Ionic liquid catalysts can significantly increase the rate of alkylation reaction, and it is of great significance to develop high-efficiency reactors suitable for this process. Based on the advantages of microreactor in process intensification, microreactor used for alkylation reaction was designed in this paper. The flow behavior of simulated fluid system was investigated and the phase separation in a wide range of throughput was achieved continuously. According to the above study, the isobutane alkylation was realized in microreactor, and the effects of residence time, temperature and droplet size on the reaction performance were studied. This research finds that the reaction can be finished in 2 s; the maximum selectivity of C₈ and TMPs/DMHs are 70.90% and 13.4 respectively, which are both higher than that in stirred tank reactor. This survey indicates that the microreactor has great potential in optimizing the alkylation reaction performance.

Key words: microreactor, alkylation, flow, separation, reaction

摘要：

离子液体催化剂可以显著提高烷基化反应速率，开发适用于该工艺的高效反应器具有重要意义。基于微反应器在过程强化方面的优势，设计了适用于烷基化反应的微反应器，考察了烷基化模拟体系的流动规律，在较大操作范围内实现了催化剂与产物的连续分相。以上述研究为基础，实现了C₄烷基化反应的微型化，分别考察了停留时间、反应温度、分散尺寸对反应性能的影响。研究结果表明，微反应器内的烷基化反应在2 s内完成。C₈选择性和TMPs（三甲基戊烷）/DMHs（二甲基己烷）分别最高可达70.90%与13.4，均高于相同反应条件下搅拌釜反应器内的反应结果，证明微反应器在优化烷基化反应性能方面拥有巨大潜力。

关键词: 微反应器, 烷基化, 流动, 分离, 反应

CLC Number:

TQ 052.5

Xuemei XUAN, Miao WANG, Dizong CAI, Rui ZHANG, Wenjie LAN. Fundamental study on flow and reaction performance of isobutane alkylation catalyzed by ionic liquid in microreactor[J]. CIESC Journal, 2021, 72(11): 5582-5589.

玄雪梅, 王苗, 蔡迪宗, 张睿, 兰文杰. 离子液体催化烷基化体系在微反应器内的流动和反应基础研究[J]. 化工学报, 2021, 72(11): 5582-5589.

Figures/Tables 14

Table 1 Components of the feedstock

混合烃组分	摩尔分数/%
异丁烷	97.7540
正丁烷	0.0675
反-2-丁烯	0.0192
正-1-丁烯	0.0254
异丁烯	0.0201
顺-2-丁烯	2.1138

Table 2 Density and viscosity of the fluid

试剂

分子式

密度/

(g/cm³)

黏度/

(mPa·s)

C₈H₁₈

Et₃NHCl-1.8AlCl₃-xCuCl

1.29

75.57

Table 3 Interfacial tension of two-phase fluid

序号	体系		界面张力/(mN/m)
序号	分散相	连续相	界面张力/(mN/m)
（W1）	正辛烷	基础离子液体	7.75
（W2）	正辛烷	复合离子液体	10.21

Fig.1 The schematic diagram of microreactor

Fig.2 The schematic overview of the experimental setup

Table 4 Parallel experiments results

产物	产物分布/%(质量)			平均值	标准偏差/%(质量)	相对标准偏差/%
产物	1#	2#	3#	平均值	标准偏差/%(质量)	相对标准偏差/%
C₅	6.98	7.66	7.84	7.49	0.40	6.06
C₆	9.15	9.7	10.72	9.86	0.53	8.08
C₇	7.38	6.79	7.75	7.31	0.52	6.62
C₈	41.05	38.39	38.78	39.41	1.54	3.64
$C 9 +$	35.44	37.46	34.92	35.94	1.56	3.73
C₈组分
TMPs	35.16	33.2	33.34	33.9	1.13	3.23
DMHs	5.61	4.89	5.17	5.22	0.43	6.95

Table 4 Parallel experiments results

产物	产物分布/%(质量)			平均值	标准偏差/%(质量)	相对标准偏差/%
产物	1#	2#	3#	平均值	标准偏差/%(质量)	相对标准偏差/%
C₅	6.98	7.66	7.84	7.49	0.40	6.06
C₆	9.15	9.7	10.72	9.86	0.53	8.08
C₇	7.38	6.79	7.75	7.31	0.52	6.62
C₈	41.05	38.39	38.78	39.41	1.54	3.64
$C 9 +$	35.44	37.46	34.92	35.94	1.56	3.73
C₈组分
TMPs	35.16	33.2	33.34	33.9	1.13	3.23
DMHs	5.61	4.89	5.17	5.22	0.43	6.95

Fig.3 Micrographs of flow regimes and flow patterns transition

Fig.4 The effect of two-phase flow rates on the droplet size

Fig.5 The effect of Qc/Qd on the characteristic size in jetting flow

Fig.6 Flow rates range of phase seperation

Fig.7 Variation of olefin conversion with residence time (Qc = 40 μl/min，Qd = 20 μl/min, ddrop = 300 μm）

Fig.8 The effect of residence time on reaction performance(Qc = 40 μl/min，Qd = 20 μl/min, ddrop = 300 μm, T = 10℃)

Fig.9 The effect of temperature on reaction performance(Qc = 40 μl/min，Qd = 20 μl/min, ddrop = 300 μm, t = 2 s)

Table 5 Effect of droplet size on yields

产物	产物分布（质量分数）/%
产物	100 μm^①	200 μm^②	500 μm^②	86 μm^③[13,31]
C₅	9.65	7.37	10.88	4.36
C₆	6.53	6.43	5.65	7.22
C₇	5.78	6.12	3.90	5.56
C₈	70.90	66.18	33.60	61.36
$C 9 +$	7.12	13.90	45.98	21.50
C₈分布
TMPs	66	59.89	29.11	56.63
DMHs	4.93	6.09	4.12	5.28
TMPs/DMHs	13.4	9.83	7.06	8.10
RON	95.3	94	83.7	92.11
烯烃转化率	94.96	99.65	99.34

Table 5 Effect of droplet size on yields

产物	产物分布（质量分数）/%
产物	100 μm^①	200 μm^②	500 μm^②	86 μm^③[13,31]
C₅	9.65	7.37	10.88	4.36
C₆	6.53	6.43	5.65	7.22
C₇	5.78	6.12	3.90	5.56
C₈	70.90	66.18	33.60	61.36
$C 9 +$	7.12	13.90	45.98	21.50
C₈分布
TMPs	66	59.89	29.11	56.63
DMHs	4.93	6.09	4.12	5.28
TMPs/DMHs	13.4	9.83	7.06	8.10
RON	95.3	94	83.7	92.11
烯烃转化率	94.96	99.65	99.34

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