Abstract:
In integrated steel manufacturing plants, by-product combustible gases from industrial processes constitute a large part of the energy balance of this type of company, enabling greater sustainability, energy efficiency and cost reduction regarding fuels purchasing. However, the processes of generation and distribution of these gases represents risks of fires and explosions potentially catastrophic for people, assets and industrial operations. Therefore, these activities require monitoring and strict control of quality parameters in order to act in a preventive manner to avoid the formation of explosive gas mixture. In this context, the Limiting Oxygen Concentration (LOC), according to the standard No. 69 of 2019 National Fire Protection Association (NFPA 69 - 2019), is reinforced as the main control parameter of combustible gas explosivity. Particularly for mixtures with varied composition the determination of this parameter becomes fundamentally more complex according to the number of combustible compounds, since each type needs a different oxygen ratio for the mixture to become flammable. In this work, technically based on the NFPA 69 – 2019 standard, the LOCs of typical compositions for Coke Oven Gas (COG), Blast Furnace Gas (BFG) and Linz Donawitz Gas (LDG) are presented from data collected in these utilities’ distribution processes at integrated steel plant in northeast of Brazil. Based on the guidelines of the same standard, safety recommended levels are presented for installations and equipment Continuously Monitored and Controlled by Safety Interlocks (CMCSI) and non-CMCSI.