Research on the basic characteristics of spray electrification for the purpose of preventing electrostatic disasters

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13963
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 25020:Safety engineering-related
• Research Institution: National Institute of Occupational Safety and Health,Japan
• Principal Investigator: Endo Yuta 独立行政法人労働者健康安全機構労働安全衛生総合研究所, 電気安全研究グループ, 主任研究員 (80778324)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 静電気 / 噴霧帯電 / 噴出帯電 / 液体 / 有機溶剤 / 火災 / 導電率

Outline of Final Research Achievements

The spray electrification (a kind of electrostatic charging phenomenon of liquids) that occurs when liquids are sprayed out of nozzles, etc., can cause fires in facilities that handle large amounts of flammable organic solvents. In this study, we investigated the conditions under which the charge generated by the spray electrification becomes large and how to reduce the charge. As a result, it was confirmed that the charge greatly depends on the conditions such as the type of liquid to be sprayed, electrical conductivity, and nozzle material. Therefore, from these conditions, the danger of spray electrification can be predicted in advance to some extent. For highly conductive liquids such as alcohol, the charge could be greatly reduced by applying a voltage of several tens of volts to the nozzle.

Free Research Field

静電気安全

Academic Significance and Societal Importance of the Research Achievements

液体の噴霧帯電に起因する火災等が起こる背景の一つに、噴霧帯電現象に関する知見の不足がある。本研究では、噴霧帯電量が液体の種類、導電率、ノズル材質等の各種噴霧条件に依存することを確認した。したがって、現場の状況とこれらの条件を照らし合わせることで、噴霧帯電の危険性をある程度予見し、より強固な安全対策を取ることが可能となる。一方で、状況によっては、噴霧帯電量そのものを低減させる対策も必要となる。そこで本研究では、アルコール等の高導電性の可燃性液体の噴霧帯電量を大きく低減可能な方法を提案し、その効果を確認した。以上の成果は、噴霧帯電に起因する災害防止を講じるうえで有用な知見になると考える。