A novel PX production shortcut through PX selectivity intensification in toluene and methanol methylation

doi:10.16085/j.issn.1000-6613.2021-1405

Abstract

Abstract:

Based on the reaction kinetics model for modified ZSM-5 catalyst with high Si/Al ratio, the factors influencing the para-xylene (PX) selectivity for methylation of toluene and methanol were discussed, and a short process for PX production was proposed based on the idea of PX selectivity intensification. The proposed short process was compared with the existing processes from the aspects of raw material utilization, energy consumption and economic indicators. The results showed that the PX selectivity for xylene can reach more than 99.7% under the conditions of short contact time, high toluene/methanol feed ratio, high diluent/methanol ratio, low reaction temperature and pressure. Compared with the existing processes, the short process was of high raw materials utilization rate, low energy consumption, process simplicity and good economy, and avoids the separation of xylene isomers. Hence, the short process had strong technical competitiveness for PX production by toluene methanol methylation.Meanwhile, by using non-petroleum-based methanol, it was helpful to form a complementary and coordinated development mode for coal chemical industry and petrochemical industry.

Key words: para-xylene, methylation of toluene-methanol, selectivity intensification, reaction kinetics, process systems, optimal design

摘要：

基于改性的高硅铝ZSM-5催化剂反应动力学模型，本文探讨了甲苯甲醇甲基化反应中影响对二甲苯（PX）选择性的因素，提出了基于选择性强化的短流程甲苯甲醇甲基化PX生产工艺，并从原料利用率、能耗以及经济指标等角度，与已有工艺进行了对比分析。结果表明，在短停留时间、高甲苯/甲醇进料比、高稀释剂/甲醇进料比、较低反应温度和压力条件下，可以促使PX在二甲苯异构体中的选择性达到99.7 %以上。短流程PX生产工艺规避了二甲苯异构体的分离，具有原料利用率高、能耗低、工艺简单的特点，具有良好的经济性。当前工艺研究进一步提升了甲苯甲醇甲基化PX生产工艺的技术竞争力，利用非石油基的甲醇，有助于形成煤化工和石油化工技术互补、协调发展的新格局。

关键词: 对二甲苯, 甲苯甲醇甲基化, 选择性强化, 反应动力学, 过程系统, 优化设计

CLC Number:

TQ206

LI Guixian, ZHANG Junqiang, YANG Yong, FAN Xueying, WANG Dongliang. A novel PX production shortcut through PX selectivity intensification in toluene and methanol methylation[J]. Chemical Industry and Engineering Progress, 2022, 41(6): 2939-2947.

李贵贤, 张军强, 杨勇, 范学英, 王东亮. 基于PX选择性强化的短流程甲苯甲醇甲基化PX生产新工艺[J]. 化工进展, 2022, 41(6): 2939-2947.

Figures/Tables 15

序号	反应方程式	反应速率表达式	指前因子 $A i$ /mol·g^-1·h^-1·Pa^-2	活化能 $E a i$ /kJ·mol^-1
R1	C₇H₈+CH₃OH $→$ p-C₈H₁₀+H₂O	$r 1 = k 1 p T p M$	5.66×10⁵	76.66
R2	p-C₈H₁₀ $→$ m-C₈H₁₀	$r 2 = k 2 p P X$	5.85×10^-2	19.24
R3	p-C₈H₁₀ $→$ o-C₈H₁₀	$r 3 = k 3 p P X$	7.71×10^-2	16.80
R4	p-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 4 = k 4 p P X p M$	1.16×10⁴	57.47
R5	o-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 5 = k 5 p O X p M$	1.16×10⁴	57.47
R6	m-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 6 = k 6 p M X p M$	1.16×10⁴	57.47
R7	2CH₃OH $→$ C₂H₄+2H₂O	$r 7 = k 7 p M 2$	1.73×10⁴	44.94

序号	反应方程式	反应速率表达式	指前因子 $A i$ /mol·g^-1·h^-1·Pa^-2	活化能 $E a i$ /kJ·mol^-1
R1	C₇H₈+CH₃OH $→$ p-C₈H₁₀+H₂O	$r 1 = k 1 p T p M$	5.66×10⁵	76.66
R2	p-C₈H₁₀ $→$ m-C₈H₁₀	$r 2 = k 2 p P X$	5.85×10^-2	19.24
R3	p-C₈H₁₀ $→$ o-C₈H₁₀	$r 3 = k 3 p P X$	7.71×10^-2	16.80
R4	p-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 4 = k 4 p P X p M$	1.16×10⁴	57.47
R5	o-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 5 = k 5 p O X p M$	1.16×10⁴	57.47
R6	m-C₈H₁₀+CH₃OH $→$ C₉H₁₂+H₂O	$r 6 = k 6 p M X p M$	1.16×10⁴	57.47
R7	2CH₃OH $→$ C₂H₄+2H₂O	$r 7 = k 7 p M 2$	1.73×10⁴	44.94

工艺参数	优化前	优化后
温度/℃	493.00	470.00
压力/kPa	300.00	350.00
空时/g·h·mol^-1	1.37	1.20
甲苯甲醇进料比	6.72	8.10
对二甲苯选择性/%	99.62	99.71
甲苯转化率/%	14.57	12.00
甲醇转化率/%	97.24	92.12

设备编号	模块名称	设备名称	工艺参数
C-101和C-102	Compr	单级压缩机	级数：单级；出口压力400kPa，效率0.80
H-101	Heater	预热器	冷物流出口温度90℃
H-102	Heater	加热器	冷物流出口温度470°C
H-103	Heater	冷却器	热物流出口温度40℃
H-104	Heater	预热器	冷物流出口温度150℃
P-101~P-107	Pump	进料泵/循环泵	泵出口压力400kPa，效率0.90
R-101	Rplug	甲基化反应器	绝热操作，压力350kPa
R-101	Rplug	甲基化反应器	催化剂：改性高硅铝比HZSM-5
V-101	Flash2	闪蒸罐	温度40℃，压力300kPa
D-101	Decanter	析水器	绝热操作，压力300kPa
T-101	Radfrac	甲苯精馏塔	操作压力200kPa；塔顶馏出物与进料比0.88
			塔顶冷凝器类型：部分汽-液
			理论板数80；进料板位置40；回流比1.55
T-102	Radfrac	对二甲苯精馏塔	操作压力200kPa；塔顶馏出物与进料比0.977
			塔顶冷凝器类型：全回流
			理论板数103；进料板位置12；回流比4.129
S-101	FSplit	分流器	弛放分流比0.1
S-102	FSplit	分流器	弛放分流比0.36

项目	物流
项目	S1	S2	S3	S4	S5	S6	S7	S8	S9	S10	S11	S12
温度/℃	25.00	25.00	25.00	25.00	470.00	478.40	40.00	40.00	27.00	135.50	165.65	224.53
压力/kPa	101.33	101.33	101.33	101.33	350.00	350.00	300.00	300.00	300.00	200.00	200.00	400.00
气相分率	1.00	0	0	0	1.00	1.00	1.00	1.00	0	1.00	0	0
总摩尔流量/kmol·h^-1	90.00	2371.00	185.50	187.00	9448.66	9579.56	95.09	855.80	2555.18	1347.72	179.13	4.12
组分摩尔流量/kmol·h^-1
H₂	90.00	0	0	0	907.68	907.68	90.00	810.01	0	7.67	0	0
C₂H₄	0	0	0	0	0.06	0.06	0	0.04	0	0.02	0	0
M	0	0	0	187.00	70.90	14.82	0.02	0.17	0	14.63	0	0
T	0	0	185.50	0	1523.41	1340.26	2.20	19.76	0	1318.15	0.15	0
OX	0	0	0	0	0	0.24	0	0	0	0	0.12	0.12
PX	0	0	0	0	0.56	179.39	0.06	0.55	0	0.01	178.59	0.18
MX	0	0	0	0	0	0.27	0	0	0	0	0.27	0
C₉H₁₂	0	0	0	0	0	3.82	0	0	0	0	0	3.82
H₂O	0	2371.00	0	0	6946.05	7133.03	2.81	25.27	2555.18	7.24	0	0

工艺	原料/kmol·h^-1		对二甲苯 /kmol·h^-1	甲苯有效利用率/%	甲醇有效利用率/%
工艺	甲苯	甲醇	对二甲苯 /kmol·h^-1	甲苯有效利用率/%	甲醇有效利用率/%
Ashraf工艺^［12］	215.24	393.65	178.59	82.97	45.36
Liu工艺^［13］	215.24	393.00	178.37	82.87	45.38
新工艺	185.50	187.00	178.59	96.27	95.50

流股名称	流股位置	起始温度 /℃	目标温度 /℃	热负荷/MW
CS1	甲醇进料预热	25.00	90.00	0.39
CS2	反应器进料	77.00	470.00	147.20
CS3	H-104进料预热器	28.90	150.00	11.06
CS4	T-101塔釜再沸器	165.90	166.10	27.80
CS5	T-102塔釜再沸器	224.00	224.50	8.74
HS1	反应器出口	479.00	40.00	171.20
HS2	T-101塔顶冷凝器	136.10	135.50	18.46
HS3	T-102塔顶冷凝器	166.20	165.70	8.73

项目	费用
TCI
塔壳成本/kUSD	$22688.6 × D 1.066 × H 1.066$
塔盘成本/kUSD	$1426.0 × D 1.55 × H$
塔径D/m	Aspen tray sizing
塔高H/m	$H = N / e T × 0.6096$
换热器成本/USD	$9367.8 × A 0.65$
换热面积A/m²	$A = Q / u × Δ T$
TOC
加热炉/USD·MW^-1·a^-1	17.1
急冷水/USD·MW^-1·a^-1	0.36
电费/USD·(kW·h·a)^-1	0.132
高压蒸汽/USD·MW^-1·a^-1	35.6
中压蒸汽/USD·MW^-1·a^-1	29.6
低压蒸汽/USD·MW^-1·a^-1	28.0
总年度成本TAC/kUSD·a^-1	$13$ TCI+TOC

项目	费用
TCI
塔壳成本/kUSD	$22688.6 × D 1.066 × H 1.066$
塔盘成本/kUSD	$1426.0 × D 1.55 × H$
塔径D/m	Aspen tray sizing
塔高H/m	$H = N / e T × 0.6096$
换热器成本/USD	$9367.8 × A 0.65$
换热面积A/m²	$A = Q / u × Δ T$
TOC
加热炉/USD·MW^-1·a^-1	17.1
急冷水/USD·MW^-1·a^-1	0.36
电费/USD·(kW·h·a)^-1	0.132
高压蒸汽/USD·MW^-1·a^-1	35.6
中压蒸汽/USD·MW^-1·a^-1	29.6
低压蒸汽/USD·MW^-1·a^-1	28.0
总年度成本TAC/kUSD·a^-1	$13$ TCI+TOC

References 21

1	顾祥万. 对二甲苯市场分析及发展建议[J]. 化工进展, 2014, 33(6): 1628-1631.
	GU Xiangwan. Paraxylene market analysis and development proposal[J]. Chemical Industry and Engineering Progress, 2014, 33(6):1628-1631.
2	ZHANG Jingui, QIAN Weizhong, KONG Chuiyan, et al. Increasing para-xylene selectivity in making aromatics from methanol with a surface-modified Zn/P/ZSM-5 catalyst[J]. ACS Catalysis, 2015, 5(5): 2982-2988.
3	陈嵩嵩, 张国帅, 霍锋, 等. 煤基大宗化学品市场及产业发展趋势[J]. 化工进展, 2020, 39(12): 5009-5020.
	CHEN Songsong, ZHANG Guoshuai, HUO Feng, et al. Market and technology development trends of coal-based bulk chemicals[J]. Chemical Industry and Engineering Progress, 2020, 39(12): 5009-5020.
4	于政锡, 徐庶亮, 张涛, 等. 对二甲苯生产技术研究进展及发展趋势[J]. 化工进展, 2020, 39(12): 4984-4992.
	YU Zhengxi, XU Shuliang, ZHANG Tao, et al. Research progress and development trend in para-xylene production technology[J]. Chemical Industry and Engineering Progress, 2020, 39(12): 4984-4992.
5	CHAKINALA Nandana, CHAKINALA Anand. Process design strategies to produce p-xylene via toluene methylation: a review[J]. Industrial & Engineering Chemistry Research, 2021, 60(15): 5331-5351.
6	张玉黎, 徐庶亮, 叶茂. 甲醇甲苯烷基化流化床反应器的数值模拟[J]. 化工进展, 2020, 39(12): 5057-5065.
	ZHANG Yuli, XU Shuliang, YE Mao. A numerical investigation on alkylation of toluene with methanol in fluidized bed reactor[J]. Chemical Industry and Engineering Progress, 2020, 39(12): 5057-5065.
7	CHEN Qingteng, LIU Jian, YANG Bo. Identifying the key steps determining the selectivity of toluene methylation with methanol over HZSM-5[J]. Nature Communications, 2021, 12(1): 3725.
8	代成义, 陈中顺, 杜康, 等. 甲醇制芳烃催化剂及相关工艺研究进展[J]. 化工进展, 2020, 39(12): 5029-5041.
	DAI Chengyi, CHEN Zhongshun, DU Kang, et al. Research progress of catalysts and related technologies for methanol to aromatics[J]. Chemical Industry and Engineering Progress, 2020, 39(12): 5029-5041.
9	HUANG Xin, WANG Ruizhuang, PAN Xu, et al. Catalyst design strategies towards highly shape-selective HZSM-5 for para-xylene through toluene alkylation[J]. Green Energy & Environment, 2020, 5(4): 385-393.
10	ZHANG Chundong, KWAK Geunjae, LEE Yun-Jo, et al. Light hydrocarbons to BTEX aromatics over Zn-modified hierarchical ZSM-5 combined with enhanced catalytic activity and stability[J]. Microporous and Mesoporous Materials, 2019, 284: 316-326.
11	张志萍, 赵岩, 吴宏宇, 等. 改性纳米HZSM-5催化剂上甲苯与甲醇的烷基化反应[J]. 催化学报, 2011, 32(7): 1280-1286.
	ZHANG Zhiping, ZHAO Yan, WU Hongyu, et al. Shape-selective alkylation of toluene with methanol over modified nano-scale HZSM-5 zeolite[J]. Chinese Journal of Catalysis, 2011, 32(7): 1280-1286.
12	ASHRAF Muhammad T, CHEBBI Rachid, DARWISH Naif A. Process of p-xylene production by highly selective methylation of toluene[J]. Industrial and Engineering Chemistry Research, 2013, 52(38): 13730-13737.
13	LIU Jing, YANG Yu, WEI Shun’an, et al. Intensified p-xylene production process through toluene and methanol alkylation[J]. Industrial & Engineering Chemistry Research, 2018, 57(38): 12829-12841.
14	BREEN John, BURCH Robbie, KULKARNI Manisha, et al. Enhanced para-xylene selectivity in the toluene alkylation reaction at ultralow contact time[J]. Journal of the American Chemical Society, 2005, 127(14): 5020-5021.
15	BREEN John, BURCH Robbie, COLLIER Paul, et al. Improved selectivity in the toluene alkylation reaction through understanding and optimising the process variables[J]. Applied Catalysis A: General, 2007, 316(1): 53-60.
16	FAN Zongliang, SU Xin, WANG Dongliang, et al. Simulation of catalytic toluene alkylation with methanol in fixed-bed reactors[J]. International Journal of Chemical Kinetics, 2021, 53(4): 558-568.
17	谭远婷, 祝然, 张新平, 等. 甲苯甲醇烷基化制对二甲苯动力学模型[J]. 化学反应工程与工艺, 2016, 32(2): 120-128.
	TAN Yuanting, ZHU Ran, ZHANG Xinping, et al. Kinetic model of toluene alkylation with methanol to para-xylene[J]. Chemical Reaction Engineering and Technology, 2016, 32(2): 120-128.
18	CHOUDHARY Vasant, NAYAK Vikram, CHOUDHARY Tushar. Single-component sorption/diffusion of cyclic compounds from their bulk liquid phase in H-ZSM-5 zeolite[J]. Industrial & Engineering Chemistry Research, 1997, 36(5): 1812-1818.
19	ALABI Wahab, ATANDA Luqman, JERMY Rabindran, et al. Kinetics of toluene alkylation with methanol catalyzed by pure and hybridized HZSM-5 catalysts[J]. Chemical Engineering Journal, 2012, 195/196: 276-288.
20	唐建远, 娄报华, 宁春利, 等. 改性的高硅铝比的HZSM-5催化剂上甲苯与甲醇的择形烷基化制对二甲苯[J]. 复旦学报(自然科学版), 2013, 52(1): 23-29.
	TANG Jianyuan, LOU Baohua, NING Chunli, et al. Shape-selective alkylation of toluene and methanol to p-xylene over modified HZSM-5 catalyst with high Si/Al molar ratios[J]. Journal of Fudan University (Natural Science), 2013, 52(1): 23-29.
21	娄报华. 甲苯甲醇烷基化合成对二甲苯催化剂研究[D]. 上海: 华东理工大学, 2014.
	LOU Baohua. Catalyst of toluene alkylation with methanol to p-xylene[D]. Shanghai: East China University of Science and Technology, 2014.

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