CIESC Journal ›› 2015, Vol. 66 ›› Issue (S2): 30-39.DOI: 10.11949/j.issn.0438-1157.20151069

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Calculation of CO2 frost point temperature in CH4+CO2+N2/C2H6 ternary mixtures

XIONG Xiaojun, LIN Wensheng   

  1. Institute of Refrigeration & Cryogenics, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2015-07-06 Revised:2015-07-12 Online:2015-08-31 Published:2015-08-31
  • Supported by:

    supported by the National Natural Science Foundation of China(51076098).

二氧化碳在CH4+CO2+N2/C2H6三元系中的结霜温度计算

熊晓俊, 林文胜   

  1. 上海交通大学制冷与低温工程研究所, 上海 200240
  • 通讯作者: 林文胜
  • 基金资助:

    国家自然科学基金项目(51076098)。

Abstract:

When natural gas encounters low temperature processes,CO2 in natural gas mixtures easily forms into frost and causes plugging problems,so it is necessary to predict the frost point temperature of CO2 in natural gas mixtures.This paper employs three different methods to calculate the frost point temperature of CO2 in CH4+CO2+N2/C2H6 ternary mixtures.The first method is to build fugacity balance model based PR equation of state.The second method is to establish pressure balance model based Dalton's law of partial pressure.And the third method is using HYSYS software.The results by three different methods are all found to be in good agreement with the experimental results.Moreover,the comparison results of three methods show that the method by PR equation of state has the highest accuracy and the method by Dalton's law of partial pressure has the lowest accuracy.Despite that the method by Dalton's law of partial pressure is not as precise as the other two methods,it can be used for fast prediction in engineering because it is simple to calculate and achieve satisfactory precision.

Key words: carbon dioxide, natural gas, frost, law of partial pressure, equation of state

摘要:

含CO2的天然气体系在历经低温工艺时,由于CO2的三相点温度(216.55 K)较高,容易凝华结霜产生固体CO2,因而有必要对CO2在天然气中的结霜温度进行计算。根据气固相平衡原理,分别采用道尔顿分压定律、PR状态方程对CO2在CH4-CO2-N2和CH4-CO2-C2H6三元系中的结霜温度进行了计算。此外,还采用HYSYS软件对CO2的结霜温度做了相应的计算。将3种方法的计算结果和实验结果进行了比较,结果表明3种方法在预测三元系中CO2的结霜温度时,都具有良好的精度。其中,PR状态方程法和HYSYS法的精度略高于道尔顿分压定律法;道尔顿分压定律法虽精度最低,但计算最简单,且也能获得满意的精度,可做工程快速估算使用。

关键词: 二氧化碳, 天然气, 结霜, 分压定律, 状态方程

CLC Number: