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In fluidized bed reactors such as Fluid Cokers TM , liquid injections are used. Good contact between liquid and bed solids is required to maximize product yields and quality, and gas-atomized nozzles are, therefore, used in all these processes. The spray nozzle technology is known to affect the liquid distribution. Therefore, the objective of this study is to assess the effect on liquid distribution of a draft tube located downstream of the spray nozzle, inside the fluidized bed. Experiments were conducted at a relevant scale, using a commercial-scale nozzle with a liquid flow rate of about 100 L/min in a large-scale pilot fluid bed containing about 7 tonnes of silica sand. Liquid injected into a fluidized bed either forms liquid-solid agglomerates or free moisture, consisting of individual particles coated with a thin layer of liquid. Several electrodes were used to map the free moisture distribution throughout the bed. A draft tube greatly improves the contact efficiency throughout the bed. It also increases the penetration of the gas-liquid jet formed by spray inside the fluidized bed.

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