Flare stack combustion apparatus and method
AssigneeSaudi Arabian Oil Company
InventorMazen M. Mashhour
Life of this patent
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Abstract
High-pressure air is discharged in the form of jets moving at a high velocity from nozzles (32) mounted on a ring manifold (30) that encircles the flare stack (10) at a predetermined distance below the flare tip (12), the upper portion of the flare stack being surrounded by an exterior shield (50) that is provided with internal guide vanes (36) at the top portion and perforated with air passages (52) at the bottom portion. The high-velocity air movement in the annular space creates a low pressure zone that in turn induces a larger volume of air from the atmosphere to enter the annular space between the shield and stack where it rises to the flame zone (58), thereby lifting the flame and enhancing turbulent air, fuel and waste gas mixing in the flame zone to minimize or eliminate smoke.
Claims21
An apparatus for enhancing the complete combustion of an undesired chemical and to thereby minimize the formation of smoke in the operation of a flaring stack, the flaring stack having an outlet for the discharge of a flare feedstream that comprises a combustible mixture formed by the undesired chemical and a fuel gas, an igniter located proximate the stack outlet for producing a flame from said combustible mixture, and a shield that is positioned coaxially around the outside surface of the stack proximate the stack outlet, the apparatus comprising:
- a. a plurality of high pressure air jet nozzles spaced apart at predetermined positions below and around the exterior periphery of the flare stack outlet in an annular space defined by the shield and stack, each of the air jet nozzles being directed toward the stack outlet and in the direction of the feedstream's movement;
- and
- b. a source of high pressure air in fluid communication with the plurality of nozzles, whereby the discharge of the air from the nozzles forms a plurality of high-velocity air jets to produce a moving air mass that draws additional atmospheric air into the mass of air moving toward the stack outlet to thereby enhance combustion of the flare feedstream;
- and
- c. a plurality of low pressure wind control nozzles positioned around the periphery of the stack outlet and directed inwardly, wherein a low pressure curtain of air is formed to flow inwardly and upwardly from the stack outlet at the base of the flame to minimize the effect of atmospheric cross winds disruptive to an optimum combustion patterns of the flame.
A method of enhancing the complete combustion of an undesired chemical and minimizing the formation of smoke from an outlet of a flaring stack during operation, the method comprising:
- a. providing a flare feedstream formed from a combustible mixture of the undesired chemical and a fuel gas;
- b. discharging the flare feedstream from the outlet of a flare stack;
- c. igniting the flare feedstream to form a flame in a combustion zone;
- d. providing a plurality of high velocity air streams in the form of air jets spaced apart at predetermined positions below and around the exterior periphery of the flare stack outlet, each of the plurality of air jets directed to move upwardly along the wall of the stack toward the combustion zone to thereby create a low-pressure zone below the end of the outlet of the flare stack, wherein the air jets cause an influx of atmospheric air into the low pressure zone and turbulence in the combustion zone to enhance combustion of the flare feedstream;
- and
- e. providing a plurality of inwardly directed, low pressure air streams from a plurality of wind control nozzles proximate the periphery of the outlet of the flare stack, wherein a low pressure curtain of air is formed to flow upwardly from the outlet at the base of the flame to minimize the effect of atmospheric cross-winds disruptive to an optimum combustion patterns of the flame.
Dependencies are inferred from the claim text.