Electric conductance method for the assessment of liquid–gas injection into a large gas–solid fluidized bed

Liquid injections are applied widely in fluidized bed reactors such as Fluid Cokers, fluid catalytic crackers and polymerization reactors. In such industrial processes, it is necessary to optimize the contact between the injected liquid and the bed solids as it has a significant effect on product yields and quality, and reactor operability.The present paper presents and tests a novel measurement method employing electrical conductance to characterize the liquid distribution in a large scale fluid bed of about 7 tonnes of silica sand, using commercial-scale Fluid Coker spray nozzles. It was used to determine the effect of increasing atomization gas-to-liquid ratio (G/L) on the liquid–solid contact efficiency. Electrodes have been employed to map the free moisture distribution through the entire bed. The results indicated that raising the G/L ratio improves the contact efficiency, especially at high G/L ratios.

► A measurement method using electrical conductance successfully applied in a large fluid bed. ► Performance of an industrial Fluid Coker nozzle was investigated implementing the method. ► Very high atomization gas flow rates in the nozzle reduce liquid trapped in agglomerates. ► Very high atomization gas flow rates also improve distribution of liquid over the bed volume. ► This means a higher yield of valuable products in a Fluid Coker, as well as improved operability.