10-100 seconds

Generally, fluidized bed reactors for gasification work on certain principles. The governing parameters related to the residence or retention time are detailed below;

1.) Air/Gas flow rate

2.) Velocity ratio

3.) Bed height & diameter

4.) Particle size

5.) Fluidization efficiency & Fluidized bed load

I feel without knowing all the above parameters, it really becomes difficult to predict such real time parameter only by the help of bed diameter singly. Moreover, as mentioned above ideal reactors do not exist rather real time datas can be monitored accordingly. So ideal retention time is not actually understood properly or can be justified scientifically in this particular case.

Still on this particular context, on basis of extensive literature review, it is found out that Average Retention Time for product gas in fludized reactor for gasification accounts to be in the range of 1.5-2.0 seconds. On basis of bed diameter ranging between 8-10 cm, 0.01 pound air/sec ,the retention time is approximately 1.75 seconds. As we are already aware that the reaction takes place in the lab scale, so the retention time too varies within a short range in order to minimize the error factor.