Dust sample collection and analysis method for assessing the risks of explosions of dust in suspension in grain receiving and storing units

Abstract

Fires and explosions resulting from organic dust in suspension represent potentially fatal risks in all operations where the formation of powdery materials in certain stages of the production process is a secondary result. This article presents a dust sample collection and analysis method to assess the risks of explosions of dust in suspension. The research method was tested in a grain (soybean) receiving, cleaning, drying, storing and shipping unit. It consisted in evaluating the total dust concentration in sectors considered at higher risk for dust explosions, which in this case study included the hopper with manual discharge, the hopper with bascule lift discharge, the dryer, the underground tunnel, the redler conveyor, the elevator, and the cleaning machine. The total concentrations in the sectors under study after 8 hours of use exceeded the recommended levels in four of the seven sampled locations. An increase in concentration was observed according to the time of operation of the unit, emphasizing that, based on the analysis of the values found, one portion of the powder settles quickly, whereas the portion with smaller particle size remains suspended in the air for a long time, representing a very high risk factor. Finally, preventive measures to avoid explosions in locations where concentrations within the detonation range can be found are described.

Keywords:
Risk management; Workplace safety; Accident prevention; Dust explosions; Receiving and storing of grains