Critical gas velocity in a three‐phase internal loop airlift reactor with low‐density particles

Abstract

In the present investigation the effects of the addition of organic additives (propanol, benzoic acid, iso-amyl alcohol and carboxymethyl cellulose) on the critical gas velocity, (U sg ) c , in an internal airlift loop reactor with low-density particles (Nylon-6 and polystyrene) were reported. Whereas the (U sg ) c was reduced by adding the above additives, it increased with solids loading and density of the particles. The draft tube-to-reactor diameter ratio (D E /D) in the range of 0.5-0.6 gave minimum (U sg ) c values. The proposed dimensionless correlation predicted the experimental data well.

Volumetric mass transfer coefficients in an internal loop airlift reactor with low‐density particles

“…All experiments were carried out at above the critical gas velocity. The critical gas velocity is the minimum gas velocity required to induce a liquid circulation velocity for complete suspension of particles 4, 29. The k L a value is the rate of gas transfer across the gas–liquid interface per unit driving force and is mainly affected by the static and dynamic properties of the liquid, geometry of the reactor and presence of solids 8, 13, 28.…”

Bioreactors: Airlift Reactors

“…Many studies have been conducted on the suspension of solids in ALRs, particularly on the use of this type of device for catalytic processes in the chemical industry (282)(283)(284)(285)(286)(287). A very important point is the minimum gas superficial velocity that leads to complete solid fluidization (161,282,285,(287)(288)(289)(290)(291)(292)(293). Hysteresis has been observed in some cases (294,295); once total fluidization has been attained, the superficial velocity can be reduced to values lower than that required to reach this state.…”