含铁化合物对三甘醇脱水性质的影响研究

Effect of iron containing compounds on dehydration properties of triethylene glycol

在天然气三甘醇脱水过程中,天然气带入的杂质在三甘醇循环多次再生过程中,会对三甘醇脱水性能产生明显影响,造成天然气脱水成本增加。以较为常见的Fe_(2)O_(3)、FeCl_(3)和FeS为例,通过室内模拟三甘醇循环再生实验研究了不同质量浓度下含铁化合物对三甘醇脱水性能的影响,分析了引起三甘醇变质的内在因素,为合理使用和延长三甘醇使用寿命提供理论基础。结果表明,在相同再生条件下,Fe_(2)O_(3)、FeCl_(3)和FeS对三甘醇变质有明显的加速作用,随着Fe_(2)O_(3)、FeCl_(3)和FeS杂质质量浓度的增加,三甘醇生成的有机杂质组分和质量浓度都增加。由于三甘醇生成的有机杂质不适应三甘醇脱水系统,使得三甘醇的含水量、发泡性质、粘度和腐蚀性明显增大,三甘醇的蒸发损失增大,表面张力下降,颜色加深且不透明。3种杂质中FeCl_(3)对三甘醇变质影响最大,其次是FeS,影响最小的是Fe_(2)O_(3)。Fe_(2)O_(3)、FeS和FeCl_(3)在三甘醇多次再生过程中引起三甘醇脱水性能明显变化的临界质量浓度分别为7.5 mg/L、7.5 mg/L和4.5 mg/L。研究结果表明,应在三甘醇再生过程中严格控制Fe_(2)O_(3)、FeCl_(3)和FeS杂质的质量浓度。

In t he process of natural gas triethylene glycol dehydration,the impurities brought by natural gas will have a significant impact on the dehydration of triethylene glycol during the repeated regeneration cycle of triethylene glycol,resulting in an increase in the cost of natural gas dehydration.Taking Fe_(2)O_(3),FeCl_(3) and FeS as examples,the effects of iron containing compounds at different mass concentrations on the dehydration properties of triethylene glycol were investigated through indoor simulated triethylene glycol cycle regeneration experiments,and the intrinsic factors causing the deterioration of triethylene glycol were analyzed to provide a theoretical basis for the rational use and prolonging service life of triethylene glycol.The results show that under the same regeneration conditions,Fe_(2)O_(3),FeCl_(3) and FeS can significantly accelerate the deterioration of triethylene glycol.With the increase of the mass concentrations of Fe_(2)O_(3),FeCl_(3) and FeS,the organic impurity components and concentrations generated by triethylene glycol increase.Due to the organic impurities generated by triethylene glycol are not suitable for triethylene glycol dehydration system,the water content,foaming properties,viscosity and corrosion of triethylene glycol are significantly increased,the evaporation loss of triethylene glycol is increased,the interfacial tension is decreased,and the color is deepened and opaque.Among the three impurities,FeCl_(3) has the greatest influence on the deterioration of triethylene glycol,followed by FeS,and the smallest is Fe_(2)O_(3).The critical mass concentrations of Fe_(2)O_(3),FeS and FeCl_(3) causing obvious changes in the dehydration performance of triethylene glycol during multiple regenerations are 7.5 mg/L,7.5 mg/L and 4.5 mg/L,respectively.The results show that the mass concentration of Fe_(2)O_(3),FeCl_(3) and FeS should be strictly controlled during the regeneration process of triethylene glycol.