Determination of Organic Partitioning Coefficients in Water-Supercritical CO2 Systems by Simultaneous in Situ UV and Near-Infrared Spectroscopies.
Determination of Organic Partitioning Coefficients in Water-Supercritical CO2 Systems by Simultaneous in Situ UV and Near-Infrared Spectroscopies.
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通过同时原位紫外和近红外光谱测定水-超临界二氧化碳系统中的有机分配系数。
DOI：
10.1021/acs.est.6b00641
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发表时间：
2016
影响因子：
11.4
通讯作者：
C. Thompson
中科院分区：
文献类型：
--
作者：
D. Bryce;H. Shao;K. Cantrell;C. Thompson
将二氧化碳注入枯竭的石油或天然气储层进行长期储存，有可能使有机化合物流动，并使其分布在沉积物和储层盐水之间。在考虑健康和环境风险时，了解这一过程很重要，但目前关于超临界CO2和水之间有机物分配的定量数据很少。在这项工作中，开发了一种高压原位测量能力，以评估CO2和水之间的有机物在与深层地下储存CO2相关的条件下的分布。该装置由一个钛反应器与石英窗口，近红外和紫外光谱检测器，和开关阀，便于定量注入到加压反应器的有机试剂。为了证明该系统的实用性，在35-65 °C和约25-150巴的范围内测定苯在水/超临界CO2中的分配系数。随着压力的增加，在CO2相的密度变化被证明有显着的影响苯的分配行为。我们的分配系数比先前通过易发生取样损失的非原位技术确定的值低约5-15倍。本文报道的原位方法可用于量化地质CO2封存情景中可能存在的各种有机化合物的分布行为。
CO2 injected into depleted oil or gas reservoirs for long-term storage has the potential to mobilize organic compounds and distribute them between sediments and reservoir brines. Understanding this process is important when considering health and environmental risks, but little quantitative data currently exists on the partitioning of organics between supercritical CO2 and water. In this work, a high-pressure, in situ measurement capability was developed to assess the distribution of organics between CO2 and water at conditions relevant to deep underground storage of CO2. The apparatus consists of a titanium reactor with quartz windows, near-infrared and UV spectroscopic detectors, and switching valves that facilitate quantitative injection of organic reagents into the pressurized reactor. To demonstrate the utility of the system, partitioning coefficients were determined for benzene in water/supercritical CO2 over the range 35-65 °C and approximately 25-150 bar. Density changes in the CO2 phase with increasing pressure were shown to have dramatic impacts on benzene's partitioning behavior. Our partitioning coefficients were approximately 5-15 times lower than values previously determined by ex situ techniques that are prone to sampling losses. The in situ methodology reported here could be applied to quantify the distribution behavior of a wide range of organic compounds that may be present in geologic CO2 storage scenarios.