Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations

Abstract

-Trinanes, P. (2017). Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations. Process Safety and Environmental Protection, Predicting concentrations of fine particles in enclosed vessels using a camera based system and CFD simulations AbstractOne of the main challenges in industries handling biomass is the consequence of the particle breakage of pelletised biomass in smaller fractions which can lead to fine particles smaller 500 ¿m that can form dust clouds in the handling and storing equipment. These dust clouds present potential health and safety hazards as well as dust explosion hazards to plant operators because the airborne dust can occur in high concentrations close to the dust explosion limits of the biomass material, during the filling process of storage silos. Preventing dust explosions and the damage of plant infrastructures requires a profound understanding of the particle/air dynamics in the dust cloud circulating in the storage silo. The limited access to the storage facilities as well as the silo size requires a detailed study of the particle/air dynamics at different scales. Lab scale experiments were conducted as a first step to establishing a new optical method for measuring particle concentrations. A small scale experimental rig was fed centrally with different sized wood pellets and a single camera and a laser was utilised to capture the dust concentration in different areas of the silo. According to the experimental results, a higher mass concentration of dust was observed near the silo wall as well as near the main particle jet. However, the mass concentrations were below the explosive limits at the area in between main particle jet and silo wall. These experimental results were then feeding into a 2D CFD simulation representing the particle dynamics in the laser sheet (2D plane). Qualitative findings show a good agreement of the particle/air dynamics between experiments and simulations. AbstractBiomass generates a increasing interest as renewable fuel and industries handling biomass show fast levels of growths over the last decade and, yet, several challenges remain in the handling, transporting and storing of biomass such as wood pellets. One challenge is the consequence of the particle breakage of pelletised biomass in smaller fractions which can lead to fine particles smaller 500 microns which can form dust clouds in the handling and storing equipment. These dust clouds present potential health and safety hazards as well as dust explosion hazards to plant operators because during the filling process of storage silos the airborne dust can occur in high concentrations close to the dust explosion limits of the 2 biomass material. Preventing dust explosions and the damage of plant infrastructures requires a profound understanding of the particle/ air dynamics in the dust cloud circulating in the storage silo. The limited access to the storage facilities as well as the silo size require a detailed study of the particle/ air dynamics a...

Overview of Health and Safety Risks in the Process of Production and Storage of Forest Biomass for Energy Purposes—A Review

“…According to [117], the explosive mixture of wood dust from biomass is at a concentration in the range of 100 g/m 3 to several kg/m 3 . In the cited work from 2015 [116], up to 50% more dust than the minimum explosive limit was detected. There is thus a risk of explosion when filling a large-capacity silo.…”

“…According to the World Health Organization (WHO), from 2021, healthy air is considered to be where the daily average concentration of PM2.5 particles does not exceed 15 µg•m −3 [115]. In the paper [116], the authors evaluated the danger of the dust component during the storage of biomass in large-capacity silos (50,000 m 3 and more). They found that in this type of biomass storage, dust particles together with fungal spores can create a dusty mixture that can be dangerous to the health of operators working with this biomass and can even form a highly flammable and explosive mixture in case of contact with a source of heat or fire.…”

A Modelling and Validation Approach for Predicting Particle Concentrations of Airborne Dust during the Filling Process of Cylindrical Silos

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