油库废气中挥发性有机物的低温脱除过程模拟分析

doi:10.16085/j.issn.1000-6613.2023-0133

摘要/Abstract

摘要：

针对可挥发性有机物（VOCs）油气脱除回收问题，本文采用一维仿真模拟了典型间壁换热器中的微量丙烷的氮气低温冷凝脱除过程。结果表明：本研究中初始丙烷分数为2.25%的气体，将出口丙烷摩尔分数降至1.26×10^-4所需换热器长度为2.85m；换热器前1m中丙烷摩尔分数降低了76%，随后1.85m仅降低23.6%；冷凝所需换热器长度与丙烷初始浓度关系如下：当丙烷初始浓度为2.0%时所需长度最短，为2.84m；低于2.0%时，影响丙烷脱除的主要因素为冷凝速率。随丙烷初始浓度继续降低，所需换热器长度呈近似抛物线上升；高于2.0%时，影响丙烷脱除的主要因素为总冷凝量。随着丙烷浓度升高，所需换热器长度呈近似线性小幅上升。本文工作可为微量油气低温冷凝脱除换热器的换热长度设计提供参考。

关键词: 废物处理, 回收, 数值模拟

Abstract:

The volatile organic compounds (VOCs) in oil depot exhaust should be removed and recycled. The present authors simulated the cryogenic condensation removal of the small quantity of propane in the mixture gas using the one-dimensional calculation method. The results showed that for gas with initial propane fraction of 2.25% the heat exchanger used in present study with a length of 2.85m was required to reduce propane molar concentration in the mixture gas to 1.26×10^-4, and the molar fraction of propane decreased by 76% in the first one meter of the heat exchanger while by only 23.6% in the next 1.85m. The length of the heat exchanger required for condensation varied with the initial concentration of propane. The shortest length, 2.84m, was required when the initial molar concentration of propane was 2.0% . When the initial molar concentration of propane was below 2.0%, the main factor affecting the removal of propane was the condensation rate, and the required heat exchanger length increased rapidly in an approximately parabolic trend as the propane initial molar concentration decreased. When the propane initial molar concentration was higher than 2.0%, the main factor affecting the removal of propane became the total quantity of propane, and the required heat exchanger length increased approximately linearly at a smaller rate as the propane concentration increased. Present study could provide a reference to the design of the length of the heat exchanger for the condensation removal of the valuable component in petroleum gas.

Key words: waste treatment, recovery, numerical simulation

中图分类号:

TE85

邵博识, 谭宏博, 张淇栋. 油库废气中挥发性有机物的低温脱除过程模拟分析[J]. 化工进展, 2023, 42(12): 6270-6277.

SHAO Boshi, TAN Hongbo, ZHANG Qidong. Simulation of cryogenic removal of volatile organic compounds from exhaust gas in oil depots[J]. Chemical Industry and Engineering Progress, 2023, 42(12): 6270-6277.

图/表 11

表1 换热通道结构与流体工况条件

参数	油气（热流体）侧	氮气（冷流体）侧
单层通道自由流截面积A/m²	5.91×10^-3	5.91×10^-3
冷凝换热面垂直于流动方向的宽度L/m	0.72	0.72
入口流速/m·s^-1	0.05	0.53
初始质量流量/g·s^-1	2.57	5.64
热端温度/K	238.15	190.15
入口压力/MPa	0.6	0.1
雷诺数Re	464.2	1229.5
入口丙烷摩尔分数/%	2.25	—
丙烷排放摩尔分数标准/10^-6	126	—

图1 间壁式换热通道内混合气冷凝传热传质示意图

图2 一维模型计算流程

表2 本文计算值与文献[5]中沿换热器长度方向的流体温度对比

长度/m	T_MIX计算值/K	T_MIX文献值/K	T_MIX误差绝对值/%	T_CN2计算值/K	T_CN2文献值/K	T_CN2误差绝对值/%
0	200	200	0	177	177	0
0.1	189.77	194.10	2.23	174.14	173.70	0.252
0.2	183.32	187.20	2.07	172.20	170.92	0.746
0.3	178.98	181.69	1.49	170.83	168.82	1.19
0.4	175.92	177.29	0.771	169.82	167.23	1.55
0.5	173.71	173.78	0.0420	169.07	166.03	1.83
0.6	172.07	170.98	0.635	168.50	165.12	2.04
0.7	170.83	168.74	1.23	168.06	164.43	2.20
0.8	169.88	166.96	1.75	167.72	163.91	2.32
0.9	169.15	165.54	2.18	167.45	163.52	2.40
1.0	168.58	164.40	2.54	167.24	163.22	2.46
1.1	168.13	163.49	2.84	167.07	162.99	2.50
1.2	167.78	162.77	3.08	166.94	162.82	2.53

图3 沿长度方向的温度与丙烷摩尔分数变化特性

图4 沿换热器长度方向各点丙烷冷凝速率

图5 式(4)中物性参数项与浓度差值项的沿长度变化情况

图6 沿换热器长度方向不同初始摩尔分数的丙烷冷凝速率分布

图7 沿换热器长度方向不同初始摩尔分数的丙烷摩尔分数分布

图8 不同丙烷初始摩尔分数下所需换热长度拟合线

表3 丙烷初始摩尔分数变化时各参数与比值ε变化情况

丙烷初始摩尔分数变化情况/%	$q m s 1 / q m s 2$	$q m ¯ 2 / q m ¯ 1$	$ε$
0.5~1.0	0.501	2.217	1.112
1.0~1.5	0.669	1.612	1.078
1.5~1.9	0.752	1.340	1.008
1.9~2.0	0.951	1.055	1.003
2.0~2.5	0.802	1.243	0.998
2.5~3.0	0.836	1.191	0.995

表3 丙烷初始摩尔分数变化时各参数与比值ε变化情况

丙烷初始摩尔分数变化情况/%	$q m s 1 / q m s 2$	$q m ¯ 2 / q m ¯ 1$	$ε$
0.5~1.0	0.501	2.217	1.112
1.0~1.5	0.669	1.612	1.078
1.5~1.9	0.752	1.340	1.008
1.9~2.0	0.951	1.055	1.003
2.0~2.5	0.802	1.243	0.998
2.5~3.0	0.836	1.191	0.995

参考文献 10

1	宋伟强, 高宇. 油气挥发污染控制技术探讨[J]. 环境保护科学, 2009, 35(6): 4-6.
	SONG Weiqiang, GAO Yu. Discussion on pollution control technology for oil gas evaporation[J]. Environmental Protection Science, 2009, 35(6): 4-6.
2	鲁洁明. 油气冷凝回收工艺的探讨与研究[D]. 南京: 东南大学, 2016.
	LU Jieming. Discussion and investigation on gasoline vapor condensation recovery technique[D]. Nanjing: Southeast University, 2016.
3	郭光臣，董文兰，张志廉. 油库设计与管理[M]. 东营：中国石油大学出版社，1991.
	GUO Guangchen, DONG Wenlan, ZHANG Zhilian. Design and management of the fuel depot[M]. Dongying: China University of Petroleum Press, 1991.
4	LI J D, SARAIREH M, THORPE G. Condensation of vapor in the presence of non-condensable gas in condensers[J]. International Journal of Heat and Mass Transfer, 2011, 54 (17/18): 4078-4089.
5	刘瑶. 天然气中二氧化碳凝华特性的研究[D]. 上海: 上海交通大学, 2013.
	LIU Yao. Research on anti-sublimation characteristics of carbon dioxide in natural gas[D]. Shanghai: Shanghai Jiaotong University.
6	王哲, 厉彦忠, 李正宇, 等. 液氦/超流氦制冷系统负压换热器仿真及优化设计[J]. 西安交通大学学报, 2016, 50(8): 143-150.
	WANG Zhe, LI Yanzhong, LI Zhengyu, et al. Simulation and optimization for sub-atmospheric heat exchanger of liquid helium/superfluid helium refrigeration system[J]. Journal of Xi’an Jiaotong University, 2016, 50(8): 143-150.
7	孙瑞. 低温CO₂捕集系统理论分析与性能优化研究[D]. 天津: 天津大学, 2019.
	SUN Rui. Performance analysis and optimization of cryogenic CO₂ capture system[D]. Tianjin: Tianjin University, 2019.
8	王雅宁. 二氧化碳凝华过程动态模型与晶体形态实验研究[D]. 杭州: 浙江大学, 2019.
	WANG Yaning. Transient model of CO₂ desublimation and experimental investigation of crystal shape[D]. Hangzhou: Zhejiang University, 2019.
9	ROHSENOW W M, CHOI H Y. Heat, mass, and momentum transfer[M]. Englewood Cliffs, N.J.: Prentice-Hall, 1961.
10	GILLILAND E R, Multicomponent rectification estimation of the number of theoretical plates as a function of reflux[J]. Industrial Engineering Chemistry, 1940, 32(9): 1220-1223.

[1]	张杰, 王放放, 夏忠林, 赵光金, 马双忱. “双碳”目标下SF₆排放现状、减排手段分析及未来展望[J]. 化工进展, 2023, 42(S1): 447-460.
[2]	郭强, 赵文凯, 肖永厚. 增强流体扰动强化变压吸附甲硫醚/氮气分离的数值模拟[J]. 化工进展, 2023, 42(S1): 64-72.
[3]	邵博识, 谭宏博. 锯齿波纹板对挥发性有机物低温脱除过程强化模拟分析[J]. 化工进展, 2023, 42(S1): 84-93.
[4]	李梦圆, 郭凡, 李群生. 聚乙烯醇生产中回收工段第三、第四精馏塔的模拟与优化[J]. 化工进展, 2023, 42(S1): 113-123.
[5]	王太, 苏硕, 李晟瑞, 马小龙, 刘春涛. 交流电场中贴壁气泡的动力学行为[J]. 化工进展, 2023, 42(S1): 133-141.
[6]	马伊, 曹世伟, 王家骏, 林立群, 邢延, 曹腾良, 卢峰, 赵振伦, 张志军. 低共熔溶剂回收废旧锂离子电池正极材料的研究进展[J]. 化工进展, 2023, 42(S1): 219-232.
[7]	陈匡胤, 李蕊兰, 童杨, 沈建华. 质子交换膜燃料电池气体扩散层结构与设计研究进展[J]. 化工进展, 2023, 42(S1): 246-259.
[8]	刘炫麟, 王驿凯, 戴苏洲, 殷勇高. 热泵中氨基甲酸铵分解反应特性及反应器结构优化[J]. 化工进展, 2023, 42(9): 4522-4530.
[9]	赵曦, 马浩然, 李平, 黄爱玲. 错位碰撞型微混合器混合性能的模拟分析与优化设计[J]. 化工进展, 2023, 42(9): 4559-4572.
[10]	钱思甜, 彭文俊, 张先明. PET熔融缩聚与溶液解聚形成环状低聚物的对比分析[J]. 化工进展, 2023, 42(9): 4808-4816.
[11]	王报英, 王皝莹, 闫军营, 汪耀明, 徐铜文. 聚合物包覆膜在金属分离回收中的研究进展[J]. 化工进展, 2023, 42(8): 3990-4004.
[12]	吕杰, 黄冲, 冯自平, 胡亚飞, 宋文吉. 基于余热回收的燃气热泵性能及控制系统[J]. 化工进展, 2023, 42(8): 4182-4192.
[13]	胡亚飞, 冯自平, 田佳垚, 宋文吉. 空气源燃气热泵系统多制热运行模式下余热回收特性[J]. 化工进展, 2023, 42(8): 4204-4211.
[14]	叶振东, 刘涵, 吕静, 张亚宁, 刘洪芝. 基于钙镁二元盐的热化学储能反应器的性能优化[J]. 化工进展, 2023, 42(8): 4307-4314.
[15]	常印龙, 周启民, 王青月, 王文俊, 李伯耿, 刘平伟. 废弃聚烯烃的高值化学回收研究进展[J]. 化工进展, 2023, 42(8): 3965-3978.