초록 ▼

A method of operating a flare assembly is provided. If it is determined that the injection of primary steam into the combustion zone is necessary to achieve smokeless operation, primary steam is injected through a steam injector assembly into the combustion zone. If it is determined that steam is no

A method of operating a flare assembly is provided. If it is determined that the injection of primary steam into the combustion zone is necessary to achieve smokeless operation, primary steam is injected through a steam injector assembly into the combustion zone. If it is determined that steam is not necessary, an alternative gas is discharged though the steam injector assembly into the combustion zone. In one embodiment, the alternative gas is heated. In another embodiment, if it is determined that steam is necessary, a maximum allowable flow rate of steam is calculated, and the flow rate of steam is modulated to achieve smokeless operation and avoid a flow rate of steam in excess of the maximum allowable flow rate of steam. A flare assembly is also provided.

대표청구항 ▼

1. A method of operating a flare assembly that receives a waste gas stream at a varying flow rate, conducts a vent gas stream to a flare tip, discharges the vent gas stream through the flare tip into a combustion zone in the atmosphere, discharges primary steam through a steam injector assembly into

1. A method of operating a flare assembly that receives a waste gas stream at a varying flow rate, conducts a vent gas stream to a flare tip, discharges the vent gas stream through the flare tip into a combustion zone in the atmosphere, discharges primary steam through a steam injector assembly into the combustion zone and burns flare gas in the combustion zone, comprising: a. providing a source of alternative gas;b. providing a source of primary steam;c. receiving the waste gas stream;d. determining the flow rate of the vent gas stream;e. discharging the vent gas stream through the flare tip into the combustion zone;f. igniting and combusting flare gas in the combustion zone;g. determining if the injection of primary steam into the combustion zone is necessary to achieve smokeless operation;h. if it is determined in step (g) that the injection of primary steam into the combustion zone is necessary to achieve smokeless operation, carrying out the following steps: i. shutting off the flow of alternative gas through the steam injector assembly into the combustion zone if alternative gas is being discharged through the steam injector assembly into the combustion zone;ii. discharging primary steam through the steam injector assembly into the combustion zone;iii. determining the flow rate of primary steam discharged through the steam injector assembly into the combustion zone;iv. modulating said flow rate of primary steam through the steam injector assembly into the combustion zone to achieve smokeless operation; andi. if it is determined in step (g) that the injection of primary steam into the combustion zone is not necessary to achieve smokeless operation, carrying out the following steps: i. shutting off the flow of primary steam through the steam injector assembly into the combustion zone if primary steam is being discharged through the steam injector assembly into the combustion zone;ii. discharging alternative gas through the steam injector assembly into the combustion zone; andiii. heating said alternative gas prior to discharging said alternative gas through the steam injector assembly into the combustion zone. 2. The method of claim 1, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation, said method further comprises the step of calculating a maximum allowable flow rate of primary steam through the steam injector assembly into the combustion zone, and said flow rate of primary steam through the steam injector assembly into the combustion zone is modulated in accordance with step (h) (iv) to achieve smokeless operation and avoid a flow rate of steam in excess of said maximum allowable flow rate of steam. 3. The method of claim 2, wherein said maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on applicable regulations with respect to operation of the flare assembly in the location in which the flare assembly is installed. 4. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the maximum steam/vent gas ratio that is to be allowed is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said maximum steam/vent gas ratio. 5. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the hydrocarbon flow rate is determined;the maximum steam/hydrocarbon ratio that is to be allowed is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said hydrocarbon flow rate and said maximum steam/hydrocarbon ratio. 6. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the minimum allowable net heating value of said flare gas is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said minimum allowable net heating value of said flare gas. 7. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the molecular weight of the vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said molecular weight. 8. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the net heating value of said vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said net heating value of said vent gas. 9. The method of claim 3, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the molecular weight of the vent gas stream is determined;the net heating value of said vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said molecular weight and net heating value of said vent gas stream. 10. The method of claim 3, wherein said method further comprises the steps of: determining the actual net heating value of the vent gas stream; anddetermining the minimum allowable net heating value of the vent gas stream; andif the actual net heating value of the vent gas stream is less than said minimum allowable net heating value of the vent gas stream, adding enrichment fuel gas to the vent gas stream in an amount sufficient to increase said actual net heating value of said vent gas stream to a level that is at least as high as said minimum allowable net heating value of the vent gas stream. 11. The method of claim 1, wherein when alternative gas is selected from the group of air, air mixed with supplemental steam and air mixed with a gas other than supplemental steam that is used as a motive fluid to educt air into the steam injector assembly. 12. A method of operating a flare assembly that receives a waste gas stream at a varying flow rate, conducts a vent gas stream to a flare tip, discharges the vent gas stream through the flare tip into a combustion zone in the atmosphere, discharges primary steam through a steam injector assembly into the combustion zone and burns flare gas in the combustion zone, comprising: a. providing a source of alternative gas;b. providing a source of primary steam;c. receiving the waste gas stream;d. determining the flow rate of the vent gas stream;e. discharging the vent gas stream through the flare tip into the combustion zone;f. igniting and combusting flare gas in the combustion zone;g. determining if the injection of primary steam into the combustion zone is necessary to achieve smokeless operation;h. if it is determined in step (g) that the injection of primary steam into the combustion zone is necessary to achieve smokeless operation, carrying out the following steps: i. shutting off the flow of alternative gas through the steam injector assembly into the combustion zone if alternative gas is being discharged through the steam injector assembly into the combustion zone;ii. discharging primary steam through the steam injector assembly into the combustion zone;iii. determining the flow rate of primary steam discharged through the steam injector assembly into the combustion zone;iv. calculating a maximum allowable flow rate of primary steam through the steam injector assembly into the combustion zone; andv. modulating said flow rate of primary steam through the steam injector assembly into the combustion zone to achieve smokeless operation and avoid a flow rate of steam in excess of said maximum allowable flow rate of steam; andi. if it is determined in step (g) that the injection of primary steam into the combustion zone is not necessary to achieve smokeless operation, carrying out the following steps: i. shutting off the flow of primary steam through the steam injector assembly into the combustion zone if primary steam is being discharged through the steam injector assembly into the combustion zone; andii. discharging alternative gas through the steam injector assembly into the combustion zone. 13. The method of claim 12, wherein said maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is determined based on applicable regulations with respect to operation of the flare assembly in the location in which the flare assembly is installed. 14. The method of claim 12, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the maximum steam/vent gas ratio that is to be allowed is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said steam/vent gas ratio. 15. The method of claim 14, wherein said maximum steam/vent gas ratio is determined based on applicable regulations with respect to operation of the flare assembly in the location in which the flare assembly is installed. 16. The method of claim 12, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the hydrocarbon flow rate is determined;the maximum steam/hydrocarbon ratio that is to be allowed is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said hydrocarbon flow rate and said maximum steam/hydrocarbon ratio. 17. The method of claim 16, wherein said maximum steam/hydrocarbon ratio is determined based on applicable regulations with respect to operation of the flare assembly in the location in which the flare assembly is installed. 18. The method of claim 12, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve said desired effect: the minimum allowable net heating value of said flare gas is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said flow rate of the vent gas stream and said minimum allowable net heating value of said flare gas. 19. The method of claim 18, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the molecular weight of the vent gas stream is determined;the net heating value of the vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said flow rate of the vent gas stream, said molecular weight and said net heating value of the vent gas. 20. The method of claim 19, wherein said minimum allowable net heating value of said flare gas is determined based on applicable regulations with respect to operation of the flare assembly in the location in which the flare assembly is installed. 21. The method of claim 12, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve said desired effect: the molecular weight of the vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said flow rate of the vent gas stream and said molecular weight. 22. The method of claim 12, wherein if it is determined in step (g) that the injection of steam into the combustion zone is necessary to achieve smokeless operation: the net heating value of said vent gas stream is determined; andsaid maximum allowable flow rate of steam through the steam injector assembly into the combustion zone is calculated based on said vent gas stream flow rate and said net heating value of said vent gas. 23. The method of claim 12, wherein said method further comprises the steps of: determining the actual net heating value of the vent gas stream; anddetermining the minimum allowable net heating value of the vent gas stream; andif the actual net heating value of the vent gas stream is less than said minimum allowable net heating value of the vent gas stream, adding enrichment fuel gas to the vent gas stream in an amount sufficient to increase said actual net heating value of said vent gas stream to a level that is at least as high as said minimum allowable net heating value of the vent gas stream. 24. The method of claim 12, wherein when alternative gas is selected from the group of air, air mixed with supplemental steam and air mixed with a gas other than supplemental steam that is used as a motive fluid to educt air into the steam injector assembly.