Development of an air-flow sorting device for the enrichment of fine particles from fire scene residues

Abstract

Detecting cigarette ash in fire scene residues is crucial for determining the cause of fire disasters. Due to the extremely low concentration of cigarette ash, direct acid leaching and spectroscopic analysis are time-consuming and unreliable. This study developed an air-flow sorting device that combines centrifugal and fluidization technologies to pre-enrich cigarette ash, a significant lightweight material. To enhance the enrichment performance of the air-flow sorting device for cigarette ash, the study systematically investigated the impact of the rotary fluidized chamber's placement angle and cylinder height on the flow field characteristics and separation performance through numerical simulations and physical experiments. The results indicate that these parameters impact separation performance by affecting static pressure distribution, tangential velocity, axial velocity, and turbulence intensity. The optimum performance is attained when the rotary fluidized chamber's placement angle is inverted and the cylinder height measures 300 mm. At a fan frequency of 40 Hz, the pressure drop, yield, d₅₀, enrichment ratio, and recovery are 2460 Pa, 20.45 %, 25.71 μm, 4.2, and 78.71 %, respectively. The findings offer theoretical guidance for the structural design and optimization of practical equipment for cigarette ash enrichment.