報告書番号

V11044

タイトル（和文）

水中セレンの簡易モニターの開発（その4）－オンラインセレンモニターの開発と実証－

タイトル（英文）

Development of simplified monitor for selenium in aqueous solution (Part 4)- Development and demonstration of the online selenium monitor -

概要 （図表や脚注は「報告書全文」に掲載しております）

当所が開発した水中セレンの簡易・迅速測定法に基づいて、プロセス排水の全セレン濃度を現場で測定できる自動測定機を試作した。本装置は、試料採取、前処理、セレン化水素の発生と定量、測定ラインの洗浄、ガスセンサの校正、等の一連の操作を自動化し、1時間で排水の全セレン濃度を得ることができる。セレン標準試料を用いた場合、0.01～0.5 mg-Se L-1の範囲において直線性に優れた検量線（r2 = 0.998）が得られ、検出下限は0.003、繰返し精度は1.6 %（0.1 mg-Se L-1において）であった。石炭火力発電所での実証試験では、モニター測定値は公定法と高い相関（相関係数 r = 0.971、測定数：88）を示し、セレン排出管理に必要なデータをリアルタイムで提供できることを実証した。

概要 （英文）

We built up a fully automated measuring equipment system for aqueous selenium referred to hereafter as the online selenium monitor. The online selenium monitor was based on rapid pretreatment methods for flue gas desulfurization (FGD) wastewater and on a simple measurement method for aqueous selenium. The pretreatment method entailed digestion with potassium permanganate to decompose organics and the reduction of selenium (VI) to selenium (IV) with hydrochloric acid. The measurement entailed the potentiometric gas sensor detection of selenium hydride generated from aqueous selenium (IV) by borohydride reduction. In the online selenium monitor, the series of measurement operations, i.e., sampling, chemical addition, cell rinsing, and calibration, was automated. The online selenium monitor coud measure selenium compounds with concentrations ranging from 0.01 to 0.5 mg L-1, and the measurement was completed within 60 min. The online selenium monitor was characterized by linear calibration in the range from 0.01 to 0.50 mg L-1 (r2 = 0.998) with a detection limit of 0.003 mg L-1 for selenium. The relative standard deviation for the 0.01 mg L-1 sample was approximately 1.6% (n = 5). To demonstrate its performance, the monitor was installed in three coal-fired power plants and effluent from an FGD unit was analyzed. An excellent correlation (r = 0.971, n = 88) was obtained between the measurements obtained using the online selenium monitor and the Japanese Industrial Standards method during the demonstration test at the third power plant. The demonstration test results confirmed that the equipment developed is a useful tool for managing selenium emission in industrial process effluent.

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