Simulation and optimization on oxidative coupling reaction of CO to dimethyl oxalate in a tubular fixed bed reactor

doi:10.11949/0438-1157.20211009

Abstract

Abstract:

For a single reaction tube in a tubular fixed bed reactor, the kinetic equation of CO oxidative coupling to dimethyl oxalate obtained under close to industrial conditions is used to establish a one-dimensional and two-dimensional pseudo-homogeneous model. The results of the single-tube experiment are compared, and the results show that the one-dimensional pseudo-homogeneous reactor model can more accurately describe the CO coupling reaction in the single-tube reactor. Furthermore, the effects of operating parameters on hot-spot temperature, reaction conversion, product selectivity and pressure drop were investigated by simulation with one-dimensional pseudo-homogeneous model. Then the sensitivity of reactor hot-spot temperature to operating parameters was carefully analyzed. The results show that coolant temperature has the most significant influence on the hot-spot temperature as well as the conversion of methyl nitrite, thus should be strictly controlled. The gas hourly space velocity low as 2000 h^-1 gives rise to temperature run-away in the reactor. The effects of inlet pressure, feed gas temperature and reactant composition on hot-spot temperature are relatively less. In order to increase the capacity of the coupling reactor and enhance the heat transfer effect in the bed, the feed space velocity can be increased to 4000 h^-1. At the same time, the compressor energy consumption can be reduced by increasing the reactor inlet pressure to 500 kPa. The research results can provide guideline for the process revamp and optimization of the existing industrial parallel tubular reactor for CO oxidative coupling.

Key words: dimethyl oxalate, oxidative coupling reaction, one-dimensional pseudo-homogeneous model, fixed bed reactor, parameter sensitivity

摘要：

针对列管式固定床反应器中的单根反应管，采用在接近工业条件下获得的CO氧化偶联制草酸二甲酯动力学方程，建立了一维、二维拟均相模型，并与单管实验结果进行了对比，结果表明一维拟均相反应器模型更能准确描述单管反应器内的CO偶联反应。进一步利用一维拟均相模型模拟计算了操作参数对床层热点温度、反应转化率、产物选择性及床层压降的影响，分析了反应器热点温度对操作参数的敏感性。计算结果表明：冷却介质温度对反应管热点温度、亚硝酸甲酯转化率有较大影响，是需要严格控制的工艺指标；较低的空速容易引起反应器飞温；反应器进口压力、原料气进料温度和反应物组成在计算范围内对反应器热点温度影响相对较小。为了提高偶联反应器的负荷和强化床层内的传热效果，可以将进料空速提高至4000 h^-1，同时，可以通过将反应器进口压力增大至500 kPa来降低压缩机能耗。研究结果可为现有列管式CO氧化偶联反应器的改进和工艺优化提供参考。

关键词: 草酸二甲酯, 氧化偶联, 一维拟均相模型, 固定床反应器, 参数敏感性

CLC Number:

TQ 203.2

Wenfa MAO, Sainan ZHENG, Nianjun LUO, Jinghong ZHOU, Yueqiang CAO, Xinggui ZHOU. Simulation and optimization on oxidative coupling reaction of CO to dimethyl oxalate in a tubular fixed bed reactor[J]. CIESC Journal, 2022, 73(1): 284-293.

毛文发, 郑赛男, 骆念军, 周静红, 曹约强, 周兴贵. 列管固定床反应器内CO氧化偶联制草酸二甲酯反应模拟及优化[J]. 化工学报, 2022, 73(1): 284-293.

Figures/Tables 12

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指标	单管实验数据	一维拟均相模型计算结果	二维拟均相模型计算结果
MN转化率/%	59.5	64.89	76.06
DMO选择性/%	95.5	89.76	87.33
DMC选择性/%	3.0	3.60	3.64
MF选择性/%	1.5	6.64	9.03
DMO时空产率/(g DMO/(g cat?h))	0.55	0.56	0.64
热点温度/K	408.2	405.86	414.42

指标	单管实验数据	一维拟均相模型计算结果	二维拟均相模型计算结果
MN转化率/%	59.5	64.89	76.06
DMO选择性/%	95.5	89.76	87.33
DMC选择性/%	3.0	3.60	3.64
MF选择性/%	1.5	6.64	9.03
DMO时空产率/(g DMO/(g cat?h))	0.55	0.56	0.64
热点温度/K	408.2	405.86	414.42

冷却介质温度/K	热点温度/K	MN 转化率/%	DMO 选择性/%	DMC 选择性/%	MF 选择性/%
393	398.91	53.59	90.84	3.39	5.77
398	405.86	64.89	89.76	3.60	6.64
403	413.86	76.50	88.50	3.80	7.70
408	423.38	87.63	87.03	3.99	8.98

冷却介质温度/K	热点温度/K	MN 转化率/%	DMO 选择性/%	DMC 选择性/%	MF 选择性/%
393	398.91	53.59	90.84	3.39	5.77
398	405.86	64.89	89.76	3.60	6.64
403	413.86	76.50	88.50	3.80	7.70
408	423.38	87.63	87.03	3.99	8.98

空速/h^-1	压降/kPa	DMO时空产率/ (g DMO/(g cat?h))	热点温度/K	MN转化率/%	DMO选择性/%	DMC选择性/%	MF选择性/%
1000	7.35	0.28	423.56	99.93	86.59	3.57	9.84
2000	27.81	0.47	409.20	81.60	88.90	3.52	7.58
3000	65.71	0.56	405.86	64.89	89.76	3.60	6.64
4000	134.93	0.60	404.28	51.82	90.10	3.71	6.12