| 摘要: |
| 水-气平衡法被广泛地应用于海水CO2分压（partial pressure,pCO2）的测定。该方法采用水-气平衡器，使海水与平衡器上部顶空中的空气进行CO2交换，达到平衡后测定该顶空空气中CO2的浓度，再换算成海水pCO2。水-气平衡器是海水pCO2测量仪器的关键部件，其性能在很大程度上决定所获得的pCO2数据的准确度和可靠性。本文介绍了水-气平衡器的平衡原理、平衡器时间常数的测量方法及影响因素，归纳了现有的4种用于海水pCO2测量的水-气平衡器即喷淋式、鼓泡式、层流式及混合式平衡器的结构与特点，着重介绍了两种新型的水气平衡器即基于射流器的鼓泡式平衡器和基于球形降膜的层流式平衡器，比较了不同水-气平衡器的尺寸、运行参数及时间常数，分析了设计和应用水-气平衡器时需考虑的因素。本文可为使用水-气平衡器测定海水pCO2的技术人员提供技术参考。 |
| 关键词: 海洋化学 二氧化碳分压 水-气平衡器 喷淋 鼓泡 层流 |
| DOI：10.3969/J.ISSN.2095-4972.2022.02.002 |
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| 基金项目:国家重点研发计划资助项目（2016YFC1400805） |
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| Air-water equilibrators for measurement of partial pressure of CO2 in seawater |
| LI Quanlong,LIU Wenjing,JIANG Kunshan,YUAN Dongxing |
| (State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology,
Xiamen University, Xiamen 361102, China) |
| Abstract: |
| Air-water equilibration methods have been commonly used in measurement of partial pressure of CO2 (pCO2) in seawater. CO2 dissolved in seawater is equilibrated between the seawater sample and air in the headspace of an air-water equilibrator. After the equilibrium is reached, CO2 concentration in the headspace air is analyzed with a gas analyzer, and pCO2 of seawater sample is calculated. The air-water equilibrator is a key component of a pCO2 measurement system because the equilibrator performance greatly affects the accuracy and reliability of the obtained pCO2 data. This paper introduced the model of equilibrium in air-water equilibrator, the method for measurement of the time constant of air-water equilibrator and the factors affecting the time constant. The structures and features of four types of air-water equilibrators (i.e., shower type, bubble type, laminary flow type and the hybrid type) were summarized. The newly reported bubble type and laminary flow type equilibrators, which are based on venture jet aerator and falling film, respectively, were presented. The sizes, operating parameters and time constants of different equilibrators were listed and compared. The factors to be considered in the equilibrator design and application were analyzed. This paper provided the technical information of air-water equilibrators for pCO2 measurement. |
| Key words: marine chemistry partial pressure of CO2 air-water equilibrator shower type bubble type laminary flow type |
