Enhancing heavy gas capture in confined spaces through ventilation control technology

Abstract

Gas leakage accidents occur frequently in confined spaces, and heavy gases with a relative density greater than 1.15 among hazardous gases and greenhouse gases are commonly stored in confined spaces. However, atmospheric pollutant emission standards are becoming more stringent, and it is essential to remove heavy gas after accidents while reducing emissions to the atmosphere. This study proposes using a heavy gas collection tank (HGCT) to safeguard the internal environment and minimize emissions to the atmosphere. The capture efficiencies applicable to heavy-gas environments under different ventilation strategies are derived. This research analyzes the impact of the exhaust rate, leakage rate, density of heavy gas, and air supply modes on the indoor concentration distribution. The results demonstrate that the mass flow rate of heavy gas into the exhaust is positively correlated with the exhaust rate, but the gas from the exhaust system contains more air. The exhaust rate should be greater than four times the space volume per hour; otherwise, heavy gas above 1000 ppm accumulates to a height of 0.67 m at ground level. Finally, attachment ventilation as make-up air helps to reduce upstream heavy gas accumulation and reduces the extension of heavy gas along the room width. Combining an HGCT with floor slope and attachment ventilation achieves an efficiency of 96.28%. This study provides valuable insights and references for preventing hazardous heavy gas leakage.