聚酯降膜增黏反应过程模拟

doi:10.13475/j.fzxb.20231201101

摘要/Abstract

摘要： 为促进对降膜熔融缩聚制备高分子量聚对苯二甲酸乙二醇酯(PET)增黏反应过程的理论认识,指导降膜反应器的设计与缩聚工艺优化,建立了降膜反应器串联五釜的连续聚合过程数学模型,以与工业生产数据匹配的五釜流程模拟结果为降膜反应釜入口物料参数,考察了PET分子量与端基量等品质指标随降膜增黏反应进程的变化,讨论了降膜反应器内温度和压力对聚合产物分子量与端基量的影响规律。结果表明:随着增黏反应的进行,可顺利得到特性黏度为1.0 dL/g以上、端羧基量为16 mmol/kg的产品;所建立的降膜反应器模型能够对增黏效果进行灵敏分析,高温低压有利于提升增黏反应效率,但过低的压力导致高黏熔体变得难处理和转移,且会增加设备成本和提高工艺精确控制的难度,温度过高则会显著增加副产物的生成;对降膜反应器选择压力为0.1 kPa左右、温度区间为285~290 ℃进行工艺参数调优,采用优化后的连续生产工艺流程最终反应器出口PET的分子量在39 000 g/mol左右;模拟结果与工业生产值吻合,可运用于分析降膜增黏反应技术应用实践。

关键词: 聚酯, 液相增黏, 反应器, 缩聚, 过程模拟, 缩聚工艺

Abstract:

Objective This research develops a comprehensive model for enhancing poly(ethylene terephthalate) (PET) production via liquid-state polymerization. By focusing on falling film flow and process simulation, the model aims to optimize the design of falling film reactors and refine the polymerization process, thereby improving the overall efficiency of industrial PET fiber production.

Method A mathematical model for continuous polymerization was developed, focusing on a six-reactor system including five reactors and an additional falling film reactor, based on a specific industrial setup. This model, calibrated with industrial data, defines the input parameters for the falling film reactor. It analyzes changes in key quality metrics like molecular weight and end-group content and explores the influences of temperature and pressure on these metrics within the reactor.

Results In this study, a mathematical model was constructed for a falling film liquid-phase polymerization reactor, tailored to simulate and analyze the distribution of component concentrations and polymer molecular weights within the reactor under varying operational conditions. The model demonstrated high accuracy, particularly under reaction conditions of 287 ℃ and 100 Pa, successfully yielding a product with an intrinsic viscosity (η_intr) value of 1.004 5 dL/g. The η_intr value at the product outlet showed only a 0.05% deviation, demonstrating the model's precision and its ability to reflect the reactor's production process accurately. The model meticulously details the axial distribution of components, showing a decrease in acid and hydroxyl end groups (E_a) and hydroxyl end group (E_g) along the reactor's length, while vinyl end groups (E_v) and degree of polymerization (DPN) increase almost linearly. Notably, the molecular flow rates of small molecules, ethylene glycol quality flow (Q_EG) and water quality flow (Q_w), exhibit a nonlinear response along the reactor length, with an initially high evaporation rate that gradually slows as the reaction proceeds and the DPN increases. Furthermore, the model assesses how molecular weight (M_WN) fluctuates with temperature changes, especially in the range of 270-300 ℃. The M_WN initially rises with the temperature increase, then declines, particularly when the temperature exceeds 290 ℃, leading to a sharp increase in E_v concentration. At 300 ℃, the concentration of E_a surges dramatically to 40 mmol/kg. Concurrently, the contents of diethylene glycol (DEG) and DEG end groups (E_DEG) decrease under these conditions. Under controlled conditions of 270-300 ℃ and 0.01-1.0 kPa, an increase in vacuum level results in a rise in M_WN and a reduction in the production of E_a, E_DEG, and DEG. This meticulous process optimization was evidenced by the enhanced M_WN value of approximately 39 000 g/mol at the outlet, underscoring the model's effectiveness in optimizing PET production.

Conclusion This study established a mathematical model for a polyester falling film liquid-state polymerization reactor, integrating a liquid phase plug flow model, a fully mixed gas phase model, and coupling PET reaction kinetics with gas-liquid mass transfer and high-viscosity fluid dynamics to simulate the polycondensation process. This model reflects the concentration of components and molecular weight distribution inside the vertical falling film reactor, indicative of the degree and progression of high-viscosity molten polymerization, typically challenging to measure online in industrial production. Exploring the relationship between component and molecular weight distribution along the reactor axis could lead to the development of direct spinning processes for polyester products with different intrinsic viscosities. The model also analyzes the impact of reaction temperature and pressure on the molecular weight and end-group content during polymer melt polycondensation, suggesting that controlling reactor temperature (285-290 ℃) and pressure (0.1 kPa) with an input melt viscosity of 0.63 dL/g and carboxyl end group of 31 mmol/kg can produce high-viscosity polyester products with an η_intr value about 1.0 dL/g. Sensitivity analysis of the model to determine optimal operating parameters offers high industrial application value.

Key words: poly(ethylene terephthalate), liquid-state polymerization, reactor, polymerization, process simulation, polymerization process

中图分类号:

TQ343.4

陈世昌, 曹峻华, 陈文兴. 聚酯降膜增黏反应过程模拟[J]. 纺织学报, 2025, 46(01): 16-24.

CHEN Shichang, CAO Junhua, CHEN Wenxing. Process simulation of falling film liquid-state polymerization of polyester[J]. Journal of Textile Research, 2025, 46(01): 16-24.

导出引用管理器 EndNote|Reference Manager|ProCite|BibTeX|RefWorks

链接本文: http://www.fzxb.org.cn/CN/10.13475/j.fzxb.20231201101

http://www.fzxb.org.cn/CN/Y2025/V46/I01/16

图/表 11

图1

表1

表2

表3

图2

图3

表4

图4

图5

图6

图7

参考文献 22

[1]	刘海霆. 关于我国聚酯工业发展趋势的分析[J]. 合成技术及应用, 2023, 38(1): 24-27.
	LIU Haiting. Analysis on the development trend of polyester industry in China[J]. Synthesis Technology and Application, 2023, 38(1):24-27.
[2]	钱伯章. 我国PET生产现状[J]. 聚酯工业, 2017, 30(1): 5-7,10.
	QIAN Bozhang. Production status of PET in China[J]. Polyester Industry, 2017, 30(1): 5-7,10.
[3]	姚军义, 王玉合, 吴旭华, 等. 国内涤纶工业丝发展现状[J]. 合成技术及应用, 2017, 32(2): 26-30.
	YAO Junyi, WANG Yuhe, WU Xuhua, et al. Development status of polyester industry filament in China[J]. Synthetic Technology and Application, 2017, 32(2): 26-30.
[4]	陈文兴, 马建平, 王建辉, 等. 涤纶工业丝熔体直纺生产技术的研发[J]. 合成纤维工业, 2013, 36(4): 1-4.
	CHEN Wenxing, MA Jianping, WANG Jianhui, et al. Development of melt direct spinning process technology for polyester industrial yarn[J]. Synthetic Fiber Industry, 2013, 36(4): 1-4.
[5]	赵玲, 朱中南. 聚酯熔融缩聚增黏过程的工程分析[J]. 聚酯工业, 2004, 17(1): 1-4.
	ZHAO Ling, ZHU Zhongnan. Engineering analysis of viscosity increasing process of polyester melt polycondensation[J]. Polyester Industry, 2004, 17(1): 1-4.
[6]	CHEN S, ZHANG L, WANG Y, et al. Residence time distribution of high viscosity fluids falling film flow down outside of industrial-scale vertical wavy wall: experimental investigation and CFD prediction[J]. Chinese Journal of Chemical Engineering, 2019, 27(7): 1586-1594.
[7]	WANG Y J, CHEN S C, LIN Q S, et al. Numerical simulation and experimental verification of the film-forming behavior of falling film flow down clamped channels with high-viscosity fluid[J]. Industrial & Engineering Chemistry Research, 2020, 59(44): 19698-19711.
[8]	CHEN S, CHEN S, GUANG S, et al. Film reaction kinetics for melt postpolycondensation of poly(ethylene terephthalate)[J]. Journal of Applied Polymer Science, 2020. DOI:10.1002/app.48988.
[9]	吕陈秋, 顾爱军, 张宇航, 等. 基于Aspen Polymer的聚酯聚合反应研究及流程模拟[J]. 化工进展, 2014, 33(5): 1086-1092,1100.
	LU Chenqiu, GU Aijun, ZHANG Yuhang, et al. PET polymerization analysis and process simulation with Aspen Polymer[J]. Chemical Industry and Engineering Progress, 2014, 33(5): 1086-1092,1100.
[10]	罗娜. 大型聚酯生产过程智能建模、控制与优化研究[D]. 上海: 华东理工大学, 2010:11-38.
	LUO Na. Research on intelligent modeling,control and optimization for poly(ethylene terephalate)process[D]. Shanghai: East China University of Science and Technology, 2010:11-38.
[11]	张素贞, 叶心宇, 陈军. 聚酯工业生产过程模型及仿真[J]. 计算机与应用化学, 1994(4): 258-268.
	ZHANG Suzhen, YE Xinyu, CHEN Jun. Modelling and simulation of PET industrial process[J]. Computers and Applied Chemistry, 1994(4): 258-268.
[12]	李文艳. 工业聚酯装置生产过程建模与分析[D]. 杭州: 浙江大学, 2011: 22-49.
	LI Wenyan. Modeling and analysis of industrial poly(ethylene terephthalate)plant[D]. Hangzhou: Zhejiang University, 2011: 22-49.
[13]	王金堂, 周兴贵, 赵玲, 等. 五釜工艺聚酯工业装置的稳态模拟[J]. 合成纤维工业, 2012, 35(1): 59-63.
	WANG Jintang, ZHOU Xinggui, ZHAO Ling, et al. A steady-state model for five-reactor PET industrial process[J]. Synthetic Fiber Industry, 2012, 35(1): 59-63.
[14]	LAUBRIET C, LECORRE B, CHOI K Y. Two-phase model for continuous final stage melt polycondensation of poly(ethylene terephthalate): 1: steady-state analy-sis[J]. Industrial & Engineering Chemistry Research, 1991, 30(1): 2-12.
[15]	RIECKMANN T, VÖLKER S. Micro-kinetics and mass transfer in poly(ethylene terephthalate) synthesis[J]. Chemical Engineering Science, 2001, 56(3): 945-953.
[16]	刘向文, 朱中南. 聚对苯二甲酸乙二醇酯缩聚反应动力学研究[J]. 聚酯工业, 1994(4): 5-8; 1995(1):17-21.
	LIU Xiangwen, ZHU Zhongnan. Study on the kinetics of polycondensation polymerization of polyethylene terephthalate[J]. Polyester Industry, 1994(4): 5-8; 1995(1):17-21.
[17]	RAVINDRANATH K, MASHELKAR R A. Modeling of poly(ethylene terephthalate) reactors[J]. Polymer Engineering & Science, 1982, 22(10): 628-636; 1984, 24(1): 30-41.
[18]	SCHEIRS J, LONG T E. Modern polyesters:chemistry and technology of polyesters and copolyesters[M]. New York: John Wiley & Sons, 2005:69-71.
[19]	RAVINDRANATH K, MASHELKAR R A. Finishing stages of PET synthesis: a comprehensive model[J]. AIChE Journal, 1984, 30(3): 415-422.
[20]	赵玲, 朱中南, 戴干策. PET缩聚过程反应与传质:Ⅰ:反应动力学研究[J]. 化学反应工程与工艺, 2000(2): 159-163.
	ZHAO Ling, ZHU Zhongnan, DAI Gance. Study on reaction and mass transfer:Ⅰ:reaction kinetics of PET polycondensation process[J]. Chemical Reaction Engineering and Technology, 2000(2): 159-163.
[21]	赵玲, 朱中南, 戴干策. PET缩聚过程反应与传质:Ⅱ:传质规律研究[J]. 化学反应工程与工艺, 2000(2): 164-168.
	ZHAO Ling, ZHU Zhongnan, DAI Gance. Study on the reaction and mass transfer:II:mass transfer rules of PET polycondensation process[J]. Chemical Reaction Engineering and Technology, 2000(2): 164-168.
[22]	RENWEN H, FENG Y, TINZHENG H, et al. The kinetics of formation of diethylene glycol in preparation of polyethylene terephthalate and its control in reactor design and operation[J]. Die Angewandte Makromolekulare Chemie, 1983, 119(1): 159-172.

Metrics

Viewed

Full text

Abstract

Cited

Shared

Discussed

反应釜类别	过程参数	E_S/%	τ/h	M_WN/(g·mol^-1)	[E_a]/(mmol·kg^-1)	[E_g]/ (mmol·kg^-1)
酯化Ⅰ釜	目标值	92.0	2.0	720~980	—	—
酯化Ⅰ釜	模拟值	92.9	1.8	917	731	1 255
酯化Ⅱ釜	目标值	96.0	2.0	1 000~1 200	—	—
酯化Ⅱ釜	模拟值	95.0	1.9	1 203	520	1 062
预缩Ⅰ釜	目标值	98.5	1.0~2.0	2 800~4 000	—	—
预缩Ⅰ釜	模拟值	99.5	1.9	4 632	127	301
预缩Ⅱ釜	目标值	99.4	1~1.5	10 000~12 000	—	—
预缩Ⅱ釜	模拟值	99.7	0.9	10 890	55	127
终缩聚釜	目标值	99.9	1~1.2	19 200~21 000	28~32	—
终缩聚釜	模拟值	99.8	1.03	19 940	31	68

参数	符号	取值
反应温度/℃	T	282
数均分子量/(g·mol^-1)	M_WN	19 940
特性黏度/(dL·g^-1)	η_intr	0.630
动力黏度/(Pa·s)	μ	300
端羟基初始浓度/(mmol·kg^-1)	[E_g]⁰	68
端羧基初始浓度/(mmol·kg^-1)	[E_a]⁰	31
酯基初始浓度/(mmol·kg^-1)	[Z]⁰	5 200
乙烯基初始浓度/(mmol·kg^-1)	[E_v]⁰	0.048
端二甘醇基初始浓度/(mmol·kg^-1)	[E_DEG]⁰	0.570
乙二醇初始浓度/(mmol·kg^-1)	[EG]⁰	0.025 7
水初始浓度/(mmol·kg^-1)	[W]⁰	0.016 2
二甘醇初始浓度/(mmol·kg^-1)	[DEG]⁰	0.012 27

序号	反应方程式
M1	E_g+E_g Z+EG
S2	E_g E_a+AA
S3	E_v+E_g Z+AA
S4	E_g+EG E_a+DEG
S5	E_g+E_DEG Z+DEG
S6	E_g+E_g E_a+E_DEG
S7	E_a+EG E_g+W
S8	E_a+E_g Z+W
S9	Z E_a+E_v

参数	目标值	模拟值
[E_a]/(mmol·kg^-1)	20	16
[E_g]/(mmol·kg^-1)	—	33
[E_v]/(mmol·kg^-1)	—	0.11
[W]/(mmol·kg^-1)	0	6.30×10^-3
[E_DEG]/(mmol·kg^-1)	—	0.28
[Z]/(mmol·kg^-1)	—	5.20×10³
[EG]/(mmol·kg^-1)	0	9.28×10^-3
[DEG]/(mmol·kg^-1)	0	2.90×10^-3
τ/h	1.000 0	1.063 0
η_intr/(dL·g^-1)	1.005 0	1.004 5