Pressure loss and droplet entrainment under spray absorber conditions

článek v časopise ve Web of Science, Jimp

en

The interaction of spray with counter-flowing flue gas causes pressure loss (Delta P) and influences droplet entrainment and sorbent loss in gas-liquid scrubbers. As these phenomena were usually investigated separately and not linked with atomizer characteristics, it is difficult to obtain insight into the scrubber operation and select an atomization device proper to particular process. Atomizers typically used in a spray column, together with pressure-swirl and twin fluid effervescent types, were tested in column-like conditions. All the atomizers were tested at the same liquid flow rate of 140 kg/h, with inlet pressure (p(in)) from 0.025 to 0.2 MPa under the counter-flow velocity (u(cf)) ranging from 0 to 1 m/s. A small-scale low-speed wind tunnel was specially designed to simulate spray column flow conditions. The Delta P and droplet entrainment were correlated with atomizer operating regimes. Empirical and analytical models of Delta P were compared with experimental results for different atomizers. Limitations of both models are discussed. The Delta P is influenced by the spray velocity at the discharge orifice (u(L)) and correlates well with the liquid kinetic energy (E-k) and Reynolds number at the discharge orifice. The atomizers working on higher p(in), provide a larger interfacial area, but yield higher E-k at the discharge orifice, causing larger Delta P and a greater risk of sorbent loss due to presence of smaller droplets.

The interaction of spray with counter-flowing flue gas causes pressure loss (Delta P) and influences droplet entrainment and sorbent loss in gas-liquid scrubbers. As these phenomena were usually investigated separately and not linked with atomizer characteristics, it is difficult to obtain insight into the scrubber operation and select an atomization device proper to particular process. Atomizers typically used in a spray column, together with pressure-swirl and twin fluid effervescent types, were tested in column-like conditions. All the atomizers were tested at the same liquid flow rate of 140 kg/h, with inlet pressure (p(in)) from 0.025 to 0.2 MPa under the counter-flow velocity (u(cf)) ranging from 0 to 1 m/s. A small-scale low-speed wind tunnel was specially designed to simulate spray column flow conditions. The Delta P and droplet entrainment were correlated with atomizer operating regimes. Empirical and analytical models of Delta P were compared with experimental results for different atomizers. Limitations of both models are discussed. The Delta P is influenced by the spray velocity at the discharge orifice (u(L)) and correlates well with the liquid kinetic energy (E-k) and Reynolds number at the discharge orifice. The atomizers working on higher p(in), provide a larger interfacial area, but yield higher E-k at the discharge orifice, causing larger Delta P and a greater risk of sorbent loss due to presence of smaller droplets.

Hollow-cone; Full-cone; Effervescent; Pressure loss; Droplet entrainment; Spray column

19.02.2025

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