CIESC Journal ›› 2014, Vol. 65 ›› Issue (z2): 25-32.DOI: 10.3969/j.issn.0438-1157.2014.z2.004

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Phase equilibrium property analysis of N2/O2/CO2 based on several state equation models

LI Shuhong, LI Xianliang, YANG Wenchao, ZHANG Yongxin, ZHANG Xiaosong   

  1. School of Energy and Environment, Southeast University, Nanjing 210096, Jiangsu, China
  • Received:2014-08-18 Revised:2014-08-28 Online:2014-12-30 Published:2014-12-30
  • Supported by:

    supported by the Peak of Six Personnel in Jiangsu Province (2013-JNHB-014) and the Natural Science Foundation of Jiangsu Province (BK2011017).

基于不同状态方程模型的N2/O2/CO2相平衡特性分析

李舒宏, 李献亮, 杨文超, 张永信, 张小松   

  1. 东南大学能源与环境学院, 江苏 南京 210096
  • 通讯作者: 李舒宏
  • 基金资助:

    江苏省六大人才高峰项目(2013-JNHB-014);江苏省自然科学基金项目(重点研究专项)(BK2011017)。

Abstract:

CO2 capture is imperative currently, cryogenic separation is one of the important methods of CCS(carbon dioxide capture and storage). The accuracy of CO2-N2 phase equilibrium property is related to the liquefied CO2 recovery and recycling purity in cryogenic method, and it will affect the choice of the system and energy consumption analysis further. N2-CO2 phase equilibria calculation based on several state equation models were made in this article. The calculation results show that the PR state equation combined with Vdw mixing rules is most suitable for N2-CO2 phase equilibrium calculation, the maximum deviation is 7.37%, the average deviation is about 3%. Then the CO2 bubble point, dew point and the temperature of sublimation at the condition of 2 MPa with the PR equation model were calculated. An energy consumption analysis about cryogenic system was made, the results show that the method combined liquefaction and sublimation achieved higher recovery and recycling purity, and compared with sublimation separation method, the former method reduce energy consumption by more than 9%. At last, an analysis about the impact of O2 on the CO2-N2 phase equilibrium property was made.

Key words: CO2 capture, phase equilibria, equation of state, mixing rules, energy consumption analysis

摘要:

当前CO2捕获日益迫切,低温捕集CO2是其中的重要方法,而N2-CO2相平衡计算的准确程度关系到低温捕集中CO2的液化回收率以及回收纯度的分析,并影响系统形式的选择及能耗分析。通过不同状态方程及混合规则进行相平衡计算方法的对比选择,结果显示结合Vdw混合规则的PR状态方程计算N2/O2相平衡特性时精度最高,最大偏差为7.37%,平均偏差在3%左右,理想方程偏差最大;之后利用PR方程进行2 MPa压力下泡露点以及凝华温度的计算,并采用液化结合凝华的方法进行系统能耗分析,结果显示此方法能达到较高回收率及回收纯度,并与仅使用凝华方法分离相比,能耗降低9%以上;此外研究了O2对N2-CO2二元系统的相平衡特性的影响。

关键词: 二氧化碳捕集, 相平衡, 状态方程, 混合规则, 能耗分析

CLC Number: