Improved equation oriented inside-out method of complex crude distillation column simulation

doi:10.11949/0438-1157.20191403

Abstract

Abstract:

Based on inside-out method, adopting the equation oriented idea, main tower and strippers were regarded as a whole for modeling. Algorithm improvement according to the characteristics of complex crude distillation tower was also conducted. Due to the simplified K model of traditional inside-out method is insensitive to the variation of component, when dealt with the system involving petroleum fraction ,it is prone to cause more iterations even abnormal temperature update in partial stages. Thus, the weighting factors for simplified K model by vapor sum rate equation were employed. Moreover, the product flow of strippers were viewed as design variables, taking example by the sum rate method to update the rate of flow, which enabled the algorithm easier to convergent. In order to verify the effective of the improved model, an atmospheric tower have been simulated when used different methods. The results show that the improved algorithm is suitable for simulation calculation of complex refinery towers.

Key words: inside-out method, equation oriented, sum rate method, complex crude distillation column, simulation

摘要：

在内外层算法的基础上，采用联立方程思想将主塔、侧线汽提塔视为一个整体进行建模，并针对复杂炼油塔的特点对算法提出了改进。首先，由于传统内外层法简化的K值模型对组成的变化不敏感，在处理带有石油的体系时，容易出现迭代次数较多，甚至部分塔板温度更新异常的问题，因此采用了汽相分数加和式推导了简化的K值模型加权因子。其次，借鉴流量加和法思想，规定侧线汽提塔的塔底产品流量作为设计变量，增强了算法收敛的稳定性。为验证改进后算法的有效性，采用不同的算法对实际的常压塔进行了模拟，结果显示改进后的算法适合应用于复杂炼油塔的模拟计算。

关键词: 内外层法, 联立方程, 流量加和法, 复杂炼油塔, 模拟

CLC Number:

TQ 015.9

Guangjie LIU, Xiaoyan SUN, Rongshan BI, Jianping WANG, Shuguang XIANG. Improved equation oriented inside-out method of complex crude distillation column simulation[J]. CIESC Journal, 2020, 71(5): 2118-2127.

刘广杰, 孙晓岩, 毕荣山, 王建平, 项曙光. 复杂炼油塔模拟的改进联立方程内外层算法[J]. 化工学报, 2020, 71(5): 2118-2127.

Figures/Tables 15

References 30

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Number	Component	Mass flow/ (kg·h^-1)	Number	Component	Mass flow/ (kg·h^-1)
1	water	233.3	8	C₂H₆	136.2
2	O₂	6.4	9	C₃H₈	200.8
3	N₂	21.2	10	IC₄	86.3
4	H₂S	2.1	11	NC₄	104.2
5	CO₂	29.9	12	C₅	41.6
6	H₂	6.2	13	crude	499209
7	CH₄	198.1

Number	Component	Mass flow/ (kg·h^-1)	Number	Component	Mass flow/ (kg·h^-1)
1	water	233.3	8	C₂H₆	136.2
2	O₂	6.4	9	C₃H₈	200.8
3	N₂	21.2	10	IC₄	86.3
4	H₂S	2.1	11	NC₄	104.2
5	CO₂	29.9	12	C₅	41.6
6	H₂	6.2	13	crude	499209
7	CH₄	198.1

Percent distillate/%	Temperature/℃
0	16.47
5	92.3
10	134.1
30	262.81
50	374.07
70	479.99
90	695.61
95	806.3
100	945.75

Percent distillate/%	Temperature/℃
0	16.47
5	92.3
10	134.1
30	262.81
50	374.07
70	479.99
90	695.61
95	806.3
100	945.75

Item	Draw stage	Return stage	Flow rate/(kg·h^-1)	Return temperature/℃
pumparound P-1	4	2	163133.1	72.2
pumparound P-2	16	14	133779.9	185
pumparound P-3	26	24	160271.6	182