Satake Sakurako, Hosoki Ai, Kuramitz Hideki, Ueda Akira
Graduate School of Sustainability Studies for Research, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan.
Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan.
Sensors (Basel). 2024 Nov 27;24(23):7580. doi: 10.3390/s24237580.
Techniques for monitoring calcium carbonate and silica deposits (scale) in geothermal power plants and hot spring facilities using fiber optic sensors have already been reported. These sensors continuously measure changes in light transmittance with a detector and, when applied to field tests, require the installation of a power supply and sensor monitoring equipment. However, on some sites, a power supply may not be available, or a specialist skilled in handling scale sensors is required. To overcome this problem, we have developed a method for evaluating scale formation that is based on a batch process that can be used by anyone. In brief, this method involves depositing scale on a section of the optical fiber sensor and then fusing this section to the optical fiber and measuring it. Using this sensor, a technician in the field can simply place the sensor in the desired location, collect the samples at any given time, and send them to the laboratory to measure their transmittance. This simple and easy method was achieved by using a hetero-core type of fiber optic. This evaluation method can measure with the same sensitivity as conventional real-time methods, while its transmittance response for the sensor corresponds to the saturation index (SI) changes in the scale components in the solution due to increases in temperature and concentration. In the field of carbon dioxide capture and storage (CCS), this evaluation method can be used to quantitatively measure the formation of carbonate minerals, and it can also be used as an indicator for determining the conditions for CO mineral fixation, as well as in experiments using batch-type autoclaves in laboratory testing. It is also expected to be used in geothermal power plants as a method for evaluating scale formation, such as that of amorphous silica, and to protect against agents that hinder stable operation.
利用光纤传感器监测地热发电厂和温泉设施中碳酸钙和二氧化硅沉积物（水垢）的技术已有报道。这些传感器通过探测器持续测量透光率的变化，应用于现场测试时，需要安装电源和传感器监测设备。然而，在一些场所可能无法提供电源，或者需要有处理水垢传感器技能的专业人员。为克服这一问题，我们开发了一种基于分批处理的水垢形成评估方法，任何人都可使用。简而言之，该方法包括在光纤传感器的一段上沉积水垢，然后将该段与光纤熔合并进行测量。使用这种传感器，现场技术人员只需将传感器放置在所需位置，在任何给定时间采集样本，然后将其送到实验室测量透光率。这种简单易行的方法是通过使用异芯型光纤实现的。这种评估方法能够以与传统实时方法相同的灵敏度进行测量，同时其对传感器的透光率响应与由于温度和浓度升高导致溶液中水垢成分的饱和指数（SI）变化相对应。在二氧化碳捕集与封存（CCS）领域，这种评估方法可用于定量测量碳酸盐矿物的形成，还可作为确定CO矿物固定条件的指标，以及在实验室测试中用于分批式高压釜的实验。它也有望在地热发电厂中用作评估水垢形成（如无定形二氧化硅水垢形成）的方法，并用于防止妨碍稳定运行的因素。
