Analysis of Potential Natural Gas Explosions in Steam Boilers: The Case of a Sugar Beet Factory

This study involved conducting a risk assessment to identify potential gas explosions in natural gas-fired steam boilers. Following the risk assessment, scenarios were developed to illustrate how explosive atmospheres might form, and the frequencies of these scenarios occurring were calculated by event tree analysis. The explosive atmospheres that could form in the event of these scenarios occurring were then classified. The highest explosion frequency (9.6 ×10-6/yr) was obtained for Scenario 4 (gas release into the boiler room due to a flange leak). As the natural ventilation of the boiler room cannot keep the background gas concentration below 25% of the lower flammable limit, the dilution is low and the boiler room was classified as Zone 1; mechanical ventilation therefore needs to be provided. Scenario 2 (activation of the pressure relief valve due to regulator failure), a primary release source, was classified as Zone 1 with a hazardous distance of about 24 m.