Heat and mass transfer based feed bottleneck identification and reengineering of multi-feed demethanizer in ethylene complex

doi:10.11949/j.issn.0438-1157.20161178

Abstract

Abstract:

In the distillation columns, feed composition and temperature always affect the mass exchange and energy utilization, and improper feed-location can cause bad behavior of the separation and energy. To solve the feed position problem of the multi-feed distillation column, a method that identifies improper feed locations is proposed. By defining the conception of the heat transfer temperature driving force and heat transfer rate, mass transfer driving force and mass transfer rate of the tray, the method using the heat/mass transfer composite curve for the bottleneck identification is presented and applied to identify bottlenecks of the multi-feed demethanizer. The strategy that adjusts the feed locations for the process reengineering can achieve the goal of the debottlenecking for the distillation. Process simulation and bottleneck analysis show that the proposed method can identify the feed bottleneck of the demethanizer and the process reengineering can realize the debottlenecking operation. The heat and mass transfer characteristics of the whole tower become better with saving more cold energy.

Key words: process system, computer simulation, distillation, demethanizer, bottleneck identification, process reengineering, numerical analysis

摘要：

精馏塔进料的组成与温度会影响塔内质量交换和能量利用，不恰当的进料会导致全塔的分离及用能效果变差。针对多进料精馏塔的组合进料问题提出一种识别不合适进料位置的方法，基于塔板的传热温差和传热量、传质浓度差和传质量计算方法提出应用传热/传质复合曲线识别精馏塔进料瓶颈的方法，并将其应用于裂解装置脱甲烷塔进料瓶颈的识别，采用调整进料位置的流程重构策略实现去瓶颈的操作。流程模拟及瓶颈分析结果表明所提出的方法能识别出脱甲烷塔的进料瓶颈，重构流程的方法能实现去瓶颈的操作，并使全塔的传质传热特性、分离效果变好，能耗降低。

关键词: 过程系统, 计算机模拟, 精馏, 脱甲烷塔, 瓶颈识别, 流程重构, 数值分析

CLC Number:

TE624

WU Bo, LUO Xionglin. Heat and mass transfer based feed bottleneck identification and reengineering of multi-feed demethanizer in ethylene complex[J]. CIESC Journal, 2016, 67(11): 4705-4715.

吴博, 罗雄麟. 基于传热/传质的乙烯裂解过程脱甲烷塔进料瓶颈识别及流程重构策略[J]. 化工学报, 2016, 67(11): 4705-4715.

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