Full-cycle optimization of acetylene conversion distribution for acetylene hydrogenation beds-in-series reactor

doi:10.11949/0438-1157.20220753

Abstract

Abstract:

During the commercial operation of acetylene hydrogenation three-beds-in-series reactor, most of acetylene hydrogenation reaction is in the first bed, the large amount of heat released by the hydrogenation reaction makes the temperature in the bed higher than the optimal reaction temperature range,which leads to the decrease of ethylene selectivity and the decrease of ethylene yield. This problem was not taken into account in the whole cycle operation optimization. Therefore, this paper first considers the effect of temperature on the accumulation of green oil, and corrects the kinetic equation of catalyst deactivation. Secondly, in order to ensure that the temperature in each bed of the reactor is within the most suitable temperature range for reaction, two schemes of acetylene conversion rate distribution in each bed of the reactor are given from the perspectives of chemical reaction engineering theory and safety in actual production process. Finally, the constraint of acetylene conversion rate is added to the conventional full-cycle operation optimization model, and the full-cycle operation optimization model of acetylene conversion rate distribution is established, and two schemes of acetylene conversion rate distribution are optimized. The optimization results show that the ethylene yield optimized by the two acetylene conversion distribution schemes is much higher than that optimized by the conventional operation, and the ethylene yield is the highest when the acetylene conversion scheme is 33∶33∶33. Considering the safety in the actual production process, the acetylene conversion distribution scheme is 43∶47∶10, which has a better result.

Key words: process system, process optimization, acetylene hydrogenation reactor, acetylene conversion distribution, catalyst deactivation

摘要：

在乙炔加氢反应器的实际生产运行过程中，乙炔加氢反应大部分在第一床层，加氢反应放出的大量热量使得床层内温度高于最佳反应温度范围，致使乙烯选择性降低，乙烯产量下降，而在进行全周期操作优化时并未考虑到此问题。因此，首先考虑温度对绿油累积的影响，修正了催化剂失活动力学方程；其次，为保证反应器各床层内温度都在最佳反应温度范围，从化学反应工程理论和实际生产过程中的安全性两个角度出发，给出两种反应器各床层乙炔转化率分配方案；最后，在常规全周期操作优化模型中添加乙炔转化率约束，建立全周期乙炔转化率分配操作优化模型，并对两种乙炔转化率分配方案进行全周期操作优化。优化结果表明，两种乙炔转化率分配方案操作优化的乙烯产量要远远高于常规操作优化，且乙炔转化率方案为33∶33∶33时，乙烯产量最高，而考虑实际生产过程中的安全性，乙炔转化率分配方案为43∶47∶10时具有更好的效果。

关键词: 过程系统, 过程优化, 乙炔加氢反应器, 乙炔转化率分配, 催化剂失活

CLC Number:

TQ 021.8

Zheng WANG, Feng XU, Xionglin LUO. Full-cycle optimization of acetylene conversion distribution for acetylene hydrogenation beds-in-series reactor[J]. CIESC Journal, 2022, 73(10): 4551-4564.

王峥, 许锋, 罗雄麟. 乙炔加氢串联反应器全周期乙炔转化率最优分配研究[J]. 化工学报, 2022, 73(10): 4551-4564.

Figures/Tables 18

Fig.1 Process flow chart of acetylene post hydrogenation

Table 1 Adjustment of reactor inlet operating conditions

床层	操作方案	乙炔转化率/%	操作点	入口温度/℃	入口氢气流量/(kg·h^-1)
床层1	当前生产方案	68.0	A	47.65	29.40
	方案Ⅰ（平均）	33.3	A′	保持	↓↓
	方案Ⅱ（安全）	45.0	A″	保持	↓
床层2	当前生产方案	28.0	B	48.65	13.92
	方案Ⅰ（平均）	33.3	B′	保持	↓
	方案Ⅱ（安全）	45.0	B″	保持	↑
床层3	当前生产方案	4.0	C	49.65	0.78
	方案Ⅰ（平均）	33.4	C′	保持	↑↑
	方案Ⅱ（安全）	10.0	C″	保持	↑

Fig.2 Relationship between bed temperature and acetylene conversion rate during reactor operation

Table 2 Operational conditions for the simulation run

项目	操作变量	符号及单位	数值
床层1	入口氢气分压	$p_{c l}^{g}$ (0,R,Γ)/kPa	29.55
	入口温度	$T_{1}^{g}$ (0,R,Γ)/K	320.8
	入口乙炔分压	$p_{a 1}^{g}$ (0,R,Γ)/kPa	29.55
	入口乙烯分压	$p_{b 1}^{g}$ (0,R,Γ)/kPa	1684.35
床层2	入口氢气分压	$p_{c 2}^{g}$ (0,R,Γ)/kPa	14.00
	入口温度	$T_{2}^{g}$ (0,R,Γ)/K	321.8
床层3	入口氢气分压	$p_{c 3}^{g}$ (0,R,Γ)/kPa	0.79
	入口温度	$T_{3}^{g}$ (0,R,Γ)/K	322.8
运行周期	时间	Γ/d	180

Table 2 Operational conditions for the simulation run

项目	操作变量	符号及单位	数值
床层1	入口氢气分压	$p_{c l}^{g}$ (0,R,Γ)/kPa	29.55
	入口温度	$T_{1}^{g}$ (0,R,Γ)/K	320.8
	入口乙炔分压	$p_{a 1}^{g}$ (0,R,Γ)/kPa	29.55
	入口乙烯分压	$p_{b 1}^{g}$ (0,R,Γ)/kPa	1684.35
床层2	入口氢气分压	$p_{c 2}^{g}$ (0,R,Γ)/kPa	14.00
	入口温度	$T_{2}^{g}$ (0,R,Γ)/K	321.8
床层3	入口氢气分压	$p_{c 3}^{g}$ (0,R,Γ)/kPa	0.79
	入口温度	$T_{3}^{g}$ (0,R,Γ)/K	322.8
运行周期	时间	Γ/d	180

Table 3 Inlet temperature change of the first reactor bed

项目	$p_{c 1}^{g}$ (0,R,Γ)/kPa	$T_{1}^{g}$ (0,R,Γ)/K
模拟1	29.55	320.8
模拟2	保持	321.8
模拟3	保持	322.8

Table 3 Inlet temperature change of the first reactor bed

项目	$p_{c 1}^{g}$ (0,R,Γ)/kPa	$T_{1}^{g}$ (0,R,Γ)/K
模拟1	29.55	320.8
模拟2	保持	321.8
模拟3	保持	322.8

Fig.3 180 days reactor run simulation of modified deactivated model

Fig.4 First bed catalyst activity of the inlet temperature change system running for 180 days of original deactivated model

Table 4 Inlet hydrogen change of the first reactor bed

项目	$T_{1}^{g}$ (0,R,Γ)/K	$p_{c 1}^{g}$ (0,R,Γ)/kPa
模拟4	320.8	27.55
模拟5	保持	28.55
模拟6	保持	29.55

Table 4 Inlet hydrogen change of the first reactor bed

项目	$T_{1}^{g}$ (0,R,Γ)/K	$p_{c 1}^{g}$ (0,R,Γ)/kPa
模拟4	320.8	27.55
模拟5	保持	28.55
模拟6	保持	29.55

Table 5 Symbolic description of full-cycle operation optimization model

符号	说明
优化目标(J)	全周期乙烯产品累积产量
乙烯产品产量(M_C)	单日乙烯产品产量
周期(Γ_f)	优化运行180 d
反应过程模型f(·)	操作优化应用的模型，表达式见式(6)~式(12)
操作优化约束g(·)	操作优化约束见表6
催化剂活性(θ)	操作优化考虑催化剂活性变化，表达式见式(18)
出口乙炔摩尔分数(α)	α为乙炔摩尔分数，α_lb=1×10^-6，α_ub=1×10^-5
状态变量(x)	各床层入口乙炔分压	各床层出口乙烯分压
	各床层入口乙烯分压	各床层出口氢气分压
	各床层出口乙炔分压	各床层出口温度

Table 6 Constraints of operation optimization

床层	优化变量(u)	符号及单位	优化约束	初值
床层1	入口温度	$T_{1}^{g}$ (0,R,Γ+1)/K	$T_{1}^{g}$ (0,R,Γ)±0.03	320.8
	入口氢气分压	$p_{c 1}^{g}$ (0,R,Γ+1)/kPa	$p_{c 1}^{g}$ (0,R,Γ)±0.05	29.55
床层2	入口温度	$T_{2}^{g}$ (0,R,Γ+1)/K	$T_{2}^{g}$ (0,R,Γ)±0.03	321.8
	入口氢气分压	$p_{c 2}^{g}$ (0,R,Γ+1)/kPa	$p_{c 2}^{g}$ (0,R,Γ)±0.05	14.00
床层3	入口温度	$T_{3}^{g}$ (0,R,Γ+1)/K	$T_{3}^{g}$ (0,R,Γ)±0.015	322.8
	入口氢气分压	$p_{c 3}^{g}$ (0,R,Γ+1)/kPa	$p_{c 3}^{g}$ (0,R,Γ)±0.015	0.79

Table 6 Constraints of operation optimization

床层	优化变量(u)	符号及单位	优化约束	初值
床层1	入口温度	$T_{1}^{g}$ (0,R,Γ+1)/K	$T_{1}^{g}$ (0,R,Γ)±0.03	320.8
	入口氢气分压	$p_{c 1}^{g}$ (0,R,Γ+1)/kPa	$p_{c 1}^{g}$ (0,R,Γ)±0.05	29.55
床层2	入口温度	$T_{2}^{g}$ (0,R,Γ+1)/K	$T_{2}^{g}$ (0,R,Γ)±0.03	321.8
	入口氢气分压	$p_{c 2}^{g}$ (0,R,Γ+1)/kPa	$p_{c 2}^{g}$ (0,R,Γ)±0.05	14.00
床层3	入口温度	$T_{3}^{g}$ (0,R,Γ+1)/K	$T_{3}^{g}$ (0,R,Γ)±0.015	322.8
	入口氢气分压	$p_{c 3}^{g}$ (0,R,Γ+1)/kPa	$p_{c 3}^{g}$ (0,R,Γ)±0.015	0.79

Fig.5 Conventional full-cycle operation optimization

Table 7 Inlet initial value of acetylene conversion rate distribution scheme

床层	优化变量(u)	Ⅰ	Ⅱ-A	Ⅱ-B	Ⅱ-C
床层1	入口温度/K	320.8	320.8	320.8	320.8
	入口氢气流量/(kg·h^-1)	13.67	18.41	19.60	20.10
床层2	入口温度/K	321.8	321.8	321.8	321.8
	入口氢气流量/(kg·h^-1)	13.63	20.25	19.30	18.90
床层3	入口温度/K	322.8	322.8	322.8	322.8
	入口氢气流量/(kg·h^-1)	13.63	2.54	2.54	2.54

Table 8 Distribution scheme of acetylene conversion rate

项目	乙炔转化率平均分配	乙炔转化率安全分配
项目	Ⅰ(33∶33∶33)	Ⅱ-A(43∶47∶10)	Ⅱ-B(45∶45∶10)	Ⅱ-C(47∶43∶10)
乙炔转化率分配附加约束	0.32≤y^[1]≤0.34	0.40≤y^[1]≤0.46	0.42≤y^[1]≤0.48	0.44≤y^[1]≤0.50
	0.32≤y^[2]≤0.34	0.44≤y^[2]≤0.50	0.42≤y^[2]≤0.48	0.40≤y^[2]≤0.46
	0.32≤y^[3]≤0.34	0.05≤y^[3]≤0.15	0.05≤y^[3]≤0.15	0.05≤y^[3]≤0.15

Fig.6 Full-cycle operation optimization of average distribution of acetylene conversion rate

Fig.7 Ethylene mass flow at reactor outlet optimized by conventional optimization and acetylene conversion average distribution scheme

Fig.8 Full-cycle operation optimization of safe distribution of acetylene conversion rate

Fig.9 Optimized outlet ethylene mass flow of each scheme

Table 9 Cumulative product yield of ethylene on system at 180 days operation

优化方案	乙炔转化率分配	180 d乙烯产品累积产量/t	180 d乙烯产品累积增量/t
当前生产方案（未优化）	无	100831.04	251.16
当前生产方案（常规优化）	无	101339.92	713.90
方案Ⅰ	33∶33∶33	101573.55	844.68
方案Ⅱ-A	43∶47∶10	101521.03	816.23
方案Ⅱ-B	45∶45∶10	101511.91	812.62
方案Ⅱ-C	47∶43∶10	101505.81	808.25

References 29

1	杜文莉, 鲍春瑜, 陈旭. 串联型乙炔加氢反应过程的动态优化[J]. 信息与控制, 2017, 46(1): 83-89.
	Du W L, Bao C Y, Chen X. Dynamic optimization of tandem acetylene hydrogenation process[J]. Information and Control, 2017, 46(1): 83-89.
2	McCue A J, Anderson J A. Recent advances in selective acetylene hydrogenation using palladium containing catalysts[J]. Frontiers of Chemical Science and Engineering, 2015, 9(2): 142-153.
3	张健, 黄邦印, 隋志军, 等. 不同Pd/Ag配比Pd-Ag/Al₂O₃催化乙炔加氢微观反应动力学分析[J]. 化工学报, 2018, 69(2): 674-681.
	Zhang J, Huang B Y, Sui Z J, et al. Microkinetic analysis of acetylene hydrogenation over Pd-Ag/Al₂O₃ catalyst with different Pd/Ag ratios[J]. CIESC Journal, 2018, 69(2): 674-681.
4	Abakumov A A, Bychko I B, Selyshchev O V, et al. Highly selective hydrogenation of acetylene over reduced graphene oxide carbocatalyst[J]. Materialia, 2021, 18: 101163.
5	Park Y, Lee S, Hyun K, et al. Breaking the inverse relationship between catalytic activity and selectivity in acetylene partial hydrogenation using dynamic metal-polymer interaction[J]. Journal of Catalysis, 2021, 404: 716-725.
6	杨方明, 张亮, 谢春丽. 碳二加氢反应器优化操作分析[J]. 当代化工, 2011, 40(10): 1007-1012.
	Yang F M, Zhang L, Xie C L. Analysis on optimized operation of acetylene converter[J]. Contemporary Chemical Industry, 2011, 40(10): 1007-1012.
7	罗雄麟. 化工过程动态学[M]. 北京: 化学工业出版社, 2005.
	Luo X L. Chemical Process Dynamics[M]. Beijing: Chemical Industry Press, 2005.
8	谢府命, 许锋, 罗雄麟. 工艺调度对乙炔加氢反应器优化运行策略的影响分析[J]. 化工学报, 2021, 72(5): 2718-2726.
	Xie F M, Xu F, Luo X L. Influence analysis of process scheduling on optimized operation strategy of acetylene hydrogenation reactor[J]. CIESC Journal, 2021, 72(5): 2718-2726.
9	张东平, 王功华. 乙炔加氢反应器的模拟与分析[J]. 石油化工, 2003, 32(5): 414-417.
	Zhang D P, Wang G H. Simulating and analysis of reactor for selective hydrogenation of acetylene[J]. Petrochemical Technology, 2003, 32(5): 414-417.
10	涂飞, 青红英, 罗雄麟, 等. 乙炔加氢反应器的先进控制(Ⅰ): 动态机理模型的建立[J]. 化工自动化及仪表, 2003, 30(1): 20-24.
	Tu F, Qing H Y, Luo X L, et al. Advanced control of acetylene hydrogenation reactor(Ⅰ): Dynamic mechanism model[J]. Control and Instruments in Chemical Industry, 2003, 30(1): 20-24.
11	Weiss G. Modelling and control of an acetylene converter[J]. Journal of Process Control, 1996, 6(1): 7-15.
12	Gobbo R, Soares R P, Lansarin M A, et al. Modeling, simulation, and optimization of a front-end system for acetylene hydrogenation reactors[J]. Brazilian Journal of Chemical Engineering, 2004, 21(4): 545-556.
13	Szukiewicz M, Kaczmarski K, Petrus R. Modelling of fixed-bed reactor: two models of industrial reactor for selective hydrogenation of acetylene[J]. Chemical Engineering Science, 1998, 53(1): 149-155.
14	谢府命, 许锋, 梁志珊, 等. 乙炔加氢反应器全周期操作优化[J]. 化工学报, 2018, 69(3): 1081-1091.
	Xie F M, Xu F, Liang Z S, et al. Full-cycle operation optimization of acetylene hydrogenation reactor[J]. CIESC Journal, 2018, 69(3): 1081-1091.
15	Houzvicka J, Pestman R, Ponec V. The role of carbonaceous deposits and support impurities in the selective hydrogenation of ethyne[J]. Catalysis Letters, 1994, 30(1/2/3/4): 289-296.
16	Asplund S. Coke formation and its effect on internal mass transfer and selectivity in Pd-catalysed acetylene hydrogenation[J]. Journal of Catalysis, 1996, 158(1): 267-278.
17	Takht R M, Sahebdelfar S. Pd-Ag/Al₂O₃ catalyst: stages of deactivation in tail-end acetylene selective hydrogenation[J]. Applied Catalysis A: General, 2016, 525: 197-203.
18	Kuhn M, Lucas M, Claus P. Precise recognition of catalyst deactivation during acetylene hydrogenation studied with the advanced TEMKIN reactor[J]. Catalysis Communications, 2015, 72: 170-173.
19	Rahimpour M R, Dehghani O, Gholipour M R, et al. A novel configuration for P d / A g / α - A l 2 O 3 catalyst regeneration in the acetylene hydrogenation reactor of a multi feed cracker[J]. Chemical Engineering Journal, 2012, 198/199: 491-502.
20	田亮, 蒋达, 钱锋. 催化剂失活条件下的碳二加氢反应器模拟与优化[J]. 化工学报, 2012, 63(1): 185-192.
	Tian L, Jiang D, Qian F. Simulation and optimization of acetylene converter with decreasing catalyst activity[J]. CIESC Journal, 2012, 63(1): 185-192.
21	Samavati M, Ebrahim H A, Dorj Y. Effect of the operating parameters on the simulation of acetylene hydrogenation reactor with catalyst deactivation[J]. Applied Catalysis A: General, 2018, 567: 45-55.
22	Brown M W, Penlidis A, Sullivan G R. Control policies for an industrial acetylene hydrogenation reactor[J]. The Canadian Journal of Chemical Engineering, 1991, 69(1): 152-164.
23	Lesieur M, Sharma S, Nath R. Advanced process control and optimization of acetylene hydrogenation reactors[C]// AIChE Spring National Meeting 15th Annual Ethylene Producers' Conference Session T9a05-Ethylene Plant Process Control. Petromont Varennes, Canada, 2003: 815-827.
24	Aeowjaroenlap H, Chotiwiriyakun K, Tiensai N, et al. Dynamic modelling and optimization of acetylene hydrogenation reactor to improve overall economics of ethylene plant[M]//Computer Aided Chemical Engineering. Amsterdam: Elsevier, 2017: 847-852.
25	戴伟, 朱警, 万文举. C₂馏分选择加氢工艺和催化剂研究进展[J]. 石油化工, 2000, 29(7): 535-540.
	Dai W, Zhu J, Wan W J. Advances in process and catalysts for selective hydrogenation of acetylene[J]. Petrochemical Technology, 2000, 29(7): 535-540.
26	朱炳辰. 化学反应工程[M]. 3版. 北京: 化学工业出版社, 2001.
	Zhu B C. Chemical Reaction Engineering[M]. 3rd ed. Beijing: Chemical Industry Press, 2001.
27	任超, 孙琳, 罗雄麟. 换热器因应结垢慢时变的控制系统重构分析[J]. 化工学报, 2021, 72(10): 5273-5283.
	Ren C, Sun L, Luo X L. Analysis on the reconfiguration of the control system of the heat exchanger in response to the slow and time-varying fouling[J]. CIESC Journal, 2021, 72(10): 5273-5283.
28	Borodziński A, Cybulski A. The kinetic model of hydrogenation of acetylene-ethylene mixtures over palladium surface covered by carbonaceous deposits[J]. Applied Catalysis A: General, 2000, 198(1/2): 51-66.
29	罗雄麟, 涂飞, 杜殿林, 等. 乙炔加氢反应器的先进控制(Ⅲ): 控制策略及其工程应用[J]. 化工自动化及仪表, 2003, 30(3): 10-15.
	Luo X L, Tu F, Du D L, et al. Advanced control of acetylene hydrogenation reactor (Ⅲ): Control strategy and its application[J]. Control and Instruments in Chemical Industry, 2003, 30(3): 10-15.

[1]	Zhewen CHEN, Junjie WEI, Yuming ZHANG. System integration and energy conversion mechanism of the power technology with integrated supercritical water gasification of coal and SOFC [J]. CIESC Journal, 2023, 74(9): 3888-3902.
[2]	Yuyuan ZHENG, Zhiwei GE, Xiangyu HAN, Liang WANG, Haisheng CHEN. Progress and prospect of medium and high temperature thermochemical energy storage of calcium-based materials [J]. CIESC Journal, 2023, 74(8): 3171-3192.
[3]	Guixian LI, Abo CAO, Wenliang MENG, Dongliang WANG, Yong YANG, Huairong ZHOU. Process design and evaluation of CO₂ to methanol coupled with SOEC [J]. CIESC Journal, 2023, 74(7): 2999-3009.
[4]	Yuanzhe SHAO, Zhonggai ZHAO, Fei LIU. Quality-related non-stationary process fault detection method by common trends model [J]. CIESC Journal, 2023, 74(6): 2522-2537.
[5]	Cheng YUN, Qianlin WANG, Feng CHEN, Xin ZHANG, Zhan DOU, Tingjun YAN. Deep-mining risk evolution path of chemical processes based on community structure [J]. CIESC Journal, 2023, 74(4): 1639-1650.
[6]	Zizong WANG, Hansheng SUO, Xueliang ZHAO. Research and construction of digital twin intelligent ethylene plant [J]. CIESC Journal, 2023, 74(3): 1175-1186.
[7]	Yalin WANG, Yuqing PAN, Chenliang LIU. Intermittent process monitoring based on GSA-LSTM dynamic structure feature extraction [J]. CIESC Journal, 2022, 73(9): 3994-4002.
[8]	Ling YANG, Guomin CUI, Zhiqiang ZHOU, Yuan XIAO. Fine search strategy applied to mass exchange network synthesis [J]. CIESC Journal, 2022, 73(7): 3145-3155.
[9]	Kun WANG, Hongbo SHI, Shuai TAN, Bing SONG, Yang TAO. Local time difference constrained neighborhood preserving embedding algorithm for fault detection [J]. CIESC Journal, 2022, 73(7): 3109-3119.
[10]	Shujun ZHANG, Shihui WANG, Xin ZHANG, Xu JI, Yiyang DAI, Yagu DANG, Li ZHOU. Surrogate-assisted multi-objective optimization of hydrogen networks with light hydrocarbon recovery unit [J]. CIESC Journal, 2022, 73(4): 1658-1672.
[11]	Wenliang MENG, Guixian LI, Huairong ZHOU, Jingwei LI, Jian WANG, Ke WANG, Xueying FAN, Dongliang WANG. A novel coal to methanol process with near zero CO₂ emission by pulverized coal gasification integrated green hydrogen [J]. CIESC Journal, 2022, 73(4): 1714-1723.
[12]	Xin ZHANG, Li ZHOU, Shihui WANG, Xu JI, Kexin BI. Integrated optimization of refinery hydrogen networks with crude oil properties fluctuations [J]. CIESC Journal, 2022, 73(4): 1631-1646.
[13]	Senshan CAO, Feng XU, Xionglin LUO. Process simulation of stream circulation system based on stability: [J]. CIESC Journal, 2022, 73(3): 1256-1269.
[14]	Yaoming CHEN,Feng XU,Xionglin LUO. A coordinated optimal margin design method for chemical process based on relative gain and priority [J]. CIESC Journal, 2022, 73(3): 1280-1290.
[15]	Jianfei ZHANG, Jiajiang LIN, Xionglin LUO, Feng XU. Modeling analysis for product distribution control and optimization of heavy oil FCCU [J]. CIESC Journal, 2022, 73(3): 1232-1245.