Method for metering catalyst in a fluid catalytic cracking catalyst injection system

1. A method for metering catalyst in a fluid catalytic cracking catalyst injection system, the method comprising:

metering catalyst from a low pressure storage vessel to a pressure vessel using a metering device, wherein the metering device determines the quantity of catalyst dispensed with respect to the storage vessel by detecting a change in an amount of catalyst in the low pressure storage vessel;

pressurizing the pressure vessel to at least about 10 pounds per square inch; and

injecting the pressurized catalyst from the pressure vessel into a fluid catalytic cracking unit.

2. The method of claim 1 , wherein the pressurizing step further comprises:

increasing the pressure within the pressure vessel from substantially atmospheric pressure to a pressure in the range of from about 10 to about 100 pounds per square inch.

3. The method of claim 1 , herein the metering step further comprises:

obtaining data from one or more load cells coupled to the low pressure vessel; and

calculating a change in the amount of catalyst disposed in the low pressure vessel using the data.

4. The method of claim 3 , wherein the calculating step further comprises:

determining a first weight of the storage vessel prior to metering; and

comparing the first weight to a second weight of the storage vessel after the metering.

5. The method of claim 1 , wherein the metering step further comprises:

sensing a first level of the catalyst present in the storage vessel prior to the metering; and

comparing the first level to a second level of catalyst present in the storage vessel after metering.

6. The method of claim 5 , wherein the first and second level of catalyst present in the storage vessel is sensed by the use of one of an optical transducer, a capacitance device, or a sonic transducer.

7. The method of claim 1 , wherein the metering step further comprises:

sensing the flow of the catalyst flowing through at least one of the storage vessel, the metering device, or a conduit coupling the storage vessel to the pressure vessel.

8. The method of claim 7 , wherein the catalyst flow is sensed by at least one of a sonic flow meter, capacitance device, or mass flow controller.

9. The method of claim 1 , further comprising:

metering catalyst from a second low pressure storage vessel to the pressure vessel using a second metering device.

10. The method of claim 9 , wherein the step of metering from the second low pressure storage vessel occurs after the injecting step.

11. The method of claim 10 , further comprising:

pressurizing the pressure vessel to at least about 10 pounds per square inch; and

injecting the pressurized catalyst from the pressure vessel into a fluid catalytic cracking unit.

12. The method of claim 9 , wherein the step of metering from the first low pressure storage vessel and the step of metering from a second low pressure storage vessel are performed prior to the injecting step.

13. A method for metering catalyst in a fluid catalytic cracking catalyst injection system, the method comprising:

determining a first quantity of catalyst disposed in a low pressure storage vessel;

transferring catalyst to a pressure vessel;

determining a second quantity of catalyst disposed in the low pressure storage vessel;

resolving a net transferred quantity of catalyst utilizing the first and second quantity of catalyst;

pressurizing the pressure vessel; and

injecting the pressurized catalyst into a fluid catalytic cracking unit.

14. A method for metering catalyst in a fluid catalytic cracking catalyst injection system having two low pressure storage vessels coupled to a pressure vessel, the method comprising:

transferring a first catalyst from a first low pressure storage vessel to a pressure vessel;

determining a quantity of the first catalyst transferred into the pressure vessel from the first low pressure storage vessel;

pressurizing the pressure vessel to at least about 10 pounds per square inch;

injecting the pressurized first catalyst from the pressure vessel into a fluid catalytic cracking unit;

transferring a second catalyst from a second low pressure storage vessel to the pressure vessel;

determining a quantity of the second catalyst transferred into the pressure vessel from the second low pressure vessel;

pressurizing the pressure vessel to at least about 10 pounds per square inch;

injecting the pressurized second catalyst from the pressure vessel into the fluid catalytic cracking unit; and

wherein the first catalyst differs from the second catalyst.

15. The method of claim 14 , wherein the step of determining the quantity of the first catalyst transferred into the pressure vessel from the first low pressure storage vessel further comprises:

metering the amount of catalyst transferred.

16. The method of claim 14 , wherein the step of determining the quantity of the first catalyst transferred into the pressure vessel from the first low pressure storage vessel further comprises:

determining a weight of catalyst transferred.

17. The method of claim 16 , wherein the step of determining the weight of the catalyst transferred further comprises:

weighing the first low pressure storage vessel.

18. The method of claim 14 , wherein the step of determining the quantity of the first catalyst transferred into the pressure vessel from the first low pressure storage vessel further comprises:

determining a change in an amount of catalyst disposed in the first low pressure storage vessel.

19. The method of claim 18 , wherein the step of determining the change in the amount of catalyst disposed in the first low pressure storage vessel further comprises:

sensing a level of catalyst disposed in the first low pressure storage vessel.

20. The method of claim 14 , wherein the step of determining the quantity of the first catalyst transferred into the pressure vessel from the first low pressure storage vessel further comprises:

sensing a metric of flow of catalyst being transferred between the first low pressure storage vessel and the pressure vessel.