摘要
采用带有高压复合电极的pH计研究了高压下二氧化碳-盐水体系的pH值变化规律。结果表明,盐水体系中通入二氧化碳气体后,溶液的pH值均随着压力升高而降低,且先急剧下降后趋于平缓。相同浓度的盐溶液,在相同压力下,氯化镁、氯化钙、氯化钠及硫酸钠溶液的pH值均低于碳酸钠和碳酸氢钠溶液。二氧化碳在碳酸钠和碳酸氢钠溶液中主要是以HCO3-的形式存在,而在氯化镁、氯化钙、氯化钠和硫酸钠溶液中主要是以H2CO3的形式存在。大庆模拟水中含有较多的NaHCO3和Na2CO3,NaHCO3和Na2CO3对模拟水的pH值起主导作用,CO2在大庆模拟水中溶解后,主要以HCO3-形式存在。10%的氯化钙溶液的pH值随着温度的升高而降低。在实验考察的温度及压力范围内,氯化钙和CO2作用不会形成不溶的碳酸盐垢。
The pH variational characteristics of CO2-brine system in high pressure were studied using pH meter with high pressure compound electrode. The results indicate that after insufflating CO2, the pH value of the brine system decreased with rising pressure and it dropped sharply at first then went gently. The pH value of MgCl2 ,CaCl2, NaCl ,Na2SO4 solution was lower than NaaCO3 and NaHCO3 with the same concentration and pressure because that CO2 existed mainly in the form of HCO3^- in Na2CO3 and NaHCO3 solution whereas in the form of H2CO3 in MgCl2 ,CaCl2 ,NaCl,Na2SO4 solution. There was a mass of NaaCO3 and NaHCO3 in Daqing modeling water which played a leading role in pH value of solution. After dissolved in Daqing modeling water, CO2 existed mainly in the form of HCO3^-. The pH value of 10% CaCl2 solution decreased with temperature rising. No insoluble carbonate was found after the reaction between CaCl2 and CO2 in the experimental temperature and pressure.
出处
《应用化工》
CAS
CSCD
2009年第4期469-473,共5页
Applied Chemical Industry
基金
国家重点基础研究发展计划资助项目(2006CB705805)
关键词
二氧化碳
盐水
PH
高压
carbon dioxide
salt solution
pH
high pressure
