I.FLUID CATALYTIC CRACKING: www.wissenschaftler-avh.in
B.CATALYST/ADDITIVES:
Q-43:
What are the most commonly used methods of adding and withdrawing FCC Catalyst to and from Regenerators?
A-43:
Fresh catalyst needs to be added in a semi-continuous method in relatively small batches, dependent on Regen inventory, to avoid excessive activity changes and increased losses. The fresh catalyst will produce significantly more coke and gas than the conditioned Ecat so it should be loaded a bit at a time to maintain stable operations.
Typically, an automatic loading hopper system is employed. This is usually a drum mounted on weight cells, with a timer system that cycles to load a pre-designated catalyst mass, pressurize, exhaust into the Regen, and then vent and refill on a time-to weight calibration. Manual loading is normally not recommended because it is harder to control and prevent the activity or loss issues.
Ecat is normally unloaded by a manual operation through the main startup/shutdown piping or sometimes through a dedicated, smaller pipe. Ecat can be unloaded relatively fast. Its rate is usually limited by the carrying air flow or piping/storage Drum temperature.
There are design guidelines for the maximum carrying air flow to limit line velocity and erosion. Typically, this value is 10-12 mps at the Drum inlet (0 pressure). Temperature is a concern if the Ecat must be removed by trucks since it can stay quite hot in the Drum for a long time.
Loading Ecat is not an issue if the Regen is not in operation, such as startup. During normal operation, Ecat would also be loaded manually from the Drum but its rate is limited by its cooling effect on the Regen inventory. If it flows too fast, the bed will cool quickly and could result in loss of SV delta-P and unstable control.
Fresh catalyst is added in small batches. A small hopper with pressure higher than the regenerator pressure is maintained.Carrier air is used as carrying medium for the catalyst. A time operated control valve controls the rate of addition. Catalyst removal is done when the catalyst level in Regenerator reaches above a level. It is done by using carrier air, a hopper with atmospheric pressure is typically used. Catalyst transfer occurs by pressure difference.
B.CATALYST/ADDITIVES:
Q-43:
What are the most commonly used methods of adding and withdrawing FCC Catalyst to and from Regenerators?
A-43:
Fresh catalyst needs to be added in a semi-continuous method in relatively small batches, dependent on Regen inventory, to avoid excessive activity changes and increased losses. The fresh catalyst will produce significantly more coke and gas than the conditioned Ecat so it should be loaded a bit at a time to maintain stable operations.
Typically, an automatic loading hopper system is employed. This is usually a drum mounted on weight cells, with a timer system that cycles to load a pre-designated catalyst mass, pressurize, exhaust into the Regen, and then vent and refill on a time-to weight calibration. Manual loading is normally not recommended because it is harder to control and prevent the activity or loss issues.
Ecat is normally unloaded by a manual operation through the main startup/shutdown piping or sometimes through a dedicated, smaller pipe. Ecat can be unloaded relatively fast. Its rate is usually limited by the carrying air flow or piping/storage Drum temperature.
There are design guidelines for the maximum carrying air flow to limit line velocity and erosion. Typically, this value is 10-12 mps at the Drum inlet (0 pressure). Temperature is a concern if the Ecat must be removed by trucks since it can stay quite hot in the Drum for a long time.
Loading Ecat is not an issue if the Regen is not in operation, such as startup. During normal operation, Ecat would also be loaded manually from the Drum but its rate is limited by its cooling effect on the Regen inventory. If it flows too fast, the bed will cool quickly and could result in loss of SV delta-P and unstable control.
Fresh catalyst is added in small batches. A small hopper with pressure higher than the regenerator pressure is maintained.Carrier air is used as carrying medium for the catalyst. A time operated control valve controls the rate of addition. Catalyst removal is done when the catalyst level in Regenerator reaches above a level. It is done by using carrier air, a hopper with atmospheric pressure is typically used. Catalyst transfer occurs by pressure difference.
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