Patent Application
20240410576
Embodiments of the present disclosure are generally directed to an air-assist flare for use in burning waste gases and, more particularly, to an air-assist flare having auto-adjusting fan speed settings and accurate gas pressure measurements.
Gas flares are combustible gas burners that are commonly used in industrial plants, such as petroleum refineries, chemical plants, natural gas processing plants, as well as oil and gas production sites. A typical flare apparatus includes a flare stack, which can extend high above the ground, and a flare tip mounted on the flare stack.
In an air-assist flare, one or more blowers are used to blow air up through the flare stack. The air-assist flare is generally useful with tanks or other low-pressure sources (e.g., 8 oz. per square inch of tank pressure). The fan allows the flare tip to draw a sufficient flow of gas and air to cleanly burn the gas.
Embodiments of the present disclosure are generally directed to an air-assist flare for use in burning waste gases and methods of operating the air-assist flare.
In one embodiment, the air-assist flare includes a flare body, a fan, a gas feed pipe, a pilot burner, a pressure sensor and a controller. The fan is configured to operate at a plurality of fan speed settings to drive a flow of air through the flare body at a plurality of flow rates. The fan speed settings include a minimum fan speed setting corresponding to a minimum flow rate, and a maximum fan speed setting corresponding to a maximum flow rate. The gas feed pipe is coupled to a source of flammable gas and includes an output port within the flare body. The pilot burner is configured to ignite a mixture of the flammable gas discharged through the output port and the flow of air. The pressure sensor is configured to generate a pressure output signal that is indicative of a pressure within the gas feed pipe. The controller is configured to adjust the fan speed setting based on the pressure output signal. When the controller detects an error in the pressure output signal, the controller sets the fan speed setting to a predetermined fan speed setting.
Another embodiment of the air-assist flare includes a flare body, a fan, a gas feed pipe, a main pipe, a pressure sensor and a controller. The fan is configured to drive a flow of air through the flare body. The gas feed pipe includes an output port within the flare body. The main pipe connects the source of flammable to the gas feed pipe. The pressure sensor includes a pitot tube within the main pipe, a tap having a first end coupled to an impact pressure opening of the pitot tube, and a pressure transducer coupled to a second end of the tap and configured to produce a pressure output signal that is indicative of a pressure at the impact pressure opening. The controller is configured to adjust a fan speed setting based on the pressure output signal.
In one embodiment of the method, the air-assist flare includes a flare body, a fan configured to operate at a plurality of fan speed settings to drive a flow of air through the flare body at a plurality of flow rates, a gas feed pipe coupled to a source of flammable gas including an output port within the flare body, a pressure sensor configured to generate a pressure output signal that is indicative of a pressure within the gas feed pipe, and a controller configured to adjust a fan speed setting based on the pressure output signal. In the method, a flow of flammable gas is delivered from the source of flammable gas to the output port through the gas feed pipe, the pressure output signal is generated using the pressure sensor, and the fan speed setting is adjusted based on the pressure output signal using the controller.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.
Embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. Elements that are identified using the same or similar reference characters refer to the same or similar elements. The various embodiments of the present disclosure may, however, be embodied in many different forms and should not be construed as limited to only those set forth herein.
Specific details are given in the following description to provide a thorough understanding of embodiments of the present disclosure. However, it is understood by those of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, frames, supports, connectors, motors, processors, and other components may not be shown, or shown in block diagram form in order to not obscure the embodiments in unnecessary detail.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosed embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed embodiments of the present disclosure belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In some embodiments, the air-assist flare 100 includes a flare body 106, a gas feed pipe 108, and a pilot burner 110. In some embodiments, the flare body 106 may be tubular, and formed of stainless steel, or another suitable material.
In some embodiments, the flare body 106 includes a fan 116 at a proximal end 118. The fan 116 may be attached to the proximal end 118 of the flare body 106 (shown), or it may be supported within the proximal end 118 of the flare body 106 by another structure.
A distal end 120 of the gas feed pipe 108 extends into the flare body 106, as shown in
The pilot burner 110 is configured to ignite the gas 124 discharged through the output port 122 of the pipe 108. The pilot burner 110 receives a flow of combustible pilot gas from a pilot gas source 130, and an ignition controller 132 controls the ignition of the discharged pilot gas. The ignition controller 132 may include one or more processors configured to execute instructions stored in memory to control the operation of the pilot burner 110, as discussed below. The ignition controller 132, which may be remotely located from the pilot burner 110, controls the ignition of the pilot gas using any suitable technique, such as through an insulated conductor. The ignition controller 132 may also control a valve, which controls the flow of the pilot gas from the gas source 130 to the pilot burner 110. The air-assist flare 100 may include a sensor 135, such as a temperature sensor (e.g., thermocouple), and the ignition controller 132 controls the ignition of the pilot burner 110 based on a signal from the sensor 135.
The fan 116 of the air-assist flare 100 is configured to pull air that is external to the bottom or proximal end 138 of the flare body 106 and drive a flow of air 140 through the flare body 106, as illustrated in
In some embodiments, the fan 116 has a diameter that is larger than the diameter of the flare body 106. In some embodiments, the fan 116 may have a diameter of 10 or more inches, such as 12 inches, and the flare body 106 may have a diameter of less than 10 inches, such as 8 inches, for example.
In some embodiments, a fan controller 146 controls the operation of the fan 116. The fan controller 146 may include one or more processors that are configured to execute instructions stored in memory to control the operation of the fan 116, as discussed below. In some embodiments, the fan controller 146 may be combined with the ignition controller 132 into a single system controller. The fan controller 146 may be remotely located from the air-assist flare 100 and control the operation of the fan 116 through an insulated cable or another suitable communication link.
In some embodiments, the fan 116 is configured to operate at a plurality of different fan speed settings to drive the flow of air 140 through the flare body 106 at a plurality of different flow rates. For example, the fan speed settings may include a minimum fan speed setting corresponding to a minimum flow rate, and a maximum fan speed setting corresponding to a maximum flow rate. Additional intermediary fan speed settings may provide additional flow rates between the minimum flow rate and the maximum flow rate.
The greater the flow rate of the gas 124 through the gas feed pipe 108, the greater the airflow 140 that is required to efficiently burn the gas 124 discharged through the output port 122. Embodiments of the flare 100 include the use of one or more sensors to estimate the flow rate of the flammable gas 124 through the gas feed pipe 108 and control the fan speed setting based on the estimated flow rate. In some embodiments, the fan controller 146 also controls the operation of the fan 116 based on a signal from the ignition controller 132 and/or the sensor 135.
In one embodiment, the system 100 includes a pressure sensor 147 that is configured to produce a pressure output signal 148 that is indicative of a pressure of the flow of flammable gas 124, such as the pressure within the gas feed pipe 108, the main pipe 126 and/or the source of flammable gas 104, for example. This pressure is related to the flow rate of the flammable gas 124 through the gas feed pipe 108. Thus, the fan controller 146 may control the fan speed setting based on the pressure output signal 148 to ensure proper burning of the gas 124 is discharged through the output port 122.
The pressure sensor 147 may take on various forms. In one embodiment, the pressure sensor 147 may be contained within the source of flammable gas 104, as indicated in phantom lines. Alternatively, as discussed below in greater detail, the pressure sensor 147 may include a tap to the pressure of the main pipe 126 and the gas feed pipe 108, as indicated by arrow 149.
In operation, the flammable gas 124 is delivered to the gas feed pipe 108 through the main pipe 126 and is discharged through the output port 122 into the interior of the flare body 106, such as adjacent a distal end 150, for example. The fan controller 146 sets the fan speed setting of the fan 116 based on the pressure output signal 148. The fan 116 drives the airflow 140 to pull air that is external to the air-assist flare 100 through the proximal end 118 and the interior of the flare body 106. The airflow 140 mixes with the gas 124 and is ignited by the pilot burner 110 to burn the flammable gas 124.
In some embodiments, the air-assist flare 100 is formed much smaller than traditional air-assist flares. For instance, in some embodiments, the flare body 106 may have a length of less than 8 feet, less than 6 feet, or less than 4 feet, such as 2-8 feet, 2-6 feet, 2-4 feet, 4-6 feet, or 5-8 feet. Accordingly, the air-assist flare 100 may be formed significantly smaller and lighter than traditional air-assist flares, which typically have a length of 10-20 feet.
When the air-assist flare 100 has the relatively smaller size, it is suitable for burning smaller volumes of combustible gas than traditional air-assist flares, such as approximately 130,000 cubic feet per day. In order to increase burning capacity, multiple air-assist flares 100 may be coupled to the same source 104 of the flammable waste gas. In some embodiments, multiple air-assist flares 100 may be coupled to the same pipe 126 or separate pipes that are coupled to the waste gas source 104. Accordingly, one may customize an arrangement of air-assist flares 100 to accommodate a volume of combustible gas that is to be burned, thereby avoiding the necessity of using an air-assist flare that is larger and more expensive than necessary for the job. Additionally, the smaller size and lower cost of the air-assist flare 100 justifies its use for low-volume applications over non-air-assist type flares having lower burning efficiencies.
In some embodiments, the main pipe 126 has a large diameter relative to the gas feed pipe 108. In some embodiments, the main pipe 126 has a diameter in the range of 6-10 inches, such as 8 inches. In some embodiments, the gas feed pipe 108 has a diameter in the range of 1.5-3.0 inches, such as 2.0 inches, for example.
A coupling 152 may be used to join the pipe 108 to the output of the pipe 126. In one example, the coupling 152 may comprise suitable flanges 155 and 156 for joining to a flange 157 of the pipe 126 and flange 158 of the pipe 108, as indicated in
In one embodiment, the main pipe 126 is oriented transversely to the gas feed pipe 108. For example, the main pipe 126 may be horizontally oriented while the gas feed pipe 108 is vertically oriented, as shown in
The ignition controller 132 and the fan controller 146 may take on any suitable form, including a single controller that performs their functions. A simplified diagram of an example of a controller 162 in accordance with embodiments of the present disclosure that may form the controller 132, the controller 146 or a combined controller, is shown in
The one or more processors 164 may be components of one or more computer-based systems, and may include one or more control circuits, microprocessor-based engine control systems, and/or one or more programmable hardware components, such as a field programmable gate array (FPGA). The memory 166 represents local and/or remote memory or computer readable media. Such memory 166 comprises any suitable patent subject matter eligible computer readable media and does not include transitory waves or signals. Examples of the memory 166 include conventional data storage devices, such as hard disks, CD-ROMs, optical storage devices, magnetic storage devices and/or other suitable data storage devices. The controller 162 may include circuitry 168 for use by the one or more processors 164 to receive input signals 169 (e.g., sensor signal 148), issue control signals 170 (e.g., signals that control the pilot burner 110 or fan 116, etc.) and/or communicate data 172, such as in response to the execution of the instructions stored in the memory 166 by the one or more processors 164.
The air-assist flare 100 may be forced to operate in extreme environmental conditions, such as hot summer conditions and cold winter conditions, and be subject to rain, snow, sand, etc., in addition to the heat from the burning gas 124. These conditions can adversely affect the components of the air-assist flare 100, such as the sensors, controllers, electronic connections, etc. Additionally, it is common to locate air-assist flares in remote locations where it must operate substantially unsupervised.
As mentioned above, it is desirable to provide the airflow 140 to ensure that a sufficient mix of the gas 124 and the air is provided at the output port 122 of the gas feed pipe 108 to facilitate complete or nearly complete combustion of the gas 124. Some embodiments of the present disclosure relate to maintaining the airflow 140 in the event of an error in the pressure output signal 148.
In one embodiment, the fan controller 146 adjusts the fan speed setting of the fan 116 to a predetermined fan speed setting when an error in the pressure output signal 148 is detected. The error may relate to the fan controller 146 failing to receive the pressure output signal 148 due to, for example, a failure of the pressure sensor 147, a failure of the controller 146, a disruption (e.g., broken wire, short, etc.) of the communication link between the pressure sensor 147 and the fan controller 146 through which the pressure output signal 148 is communicated, or another failure that prevents the fan controller 146 from receiving or processing the pressure output signal 148. The error may also relate to the pressure value indicated by the pressure output signal 148 being out of the expected range for the signal, or another type of error.
In one embodiment, the predetermined fan speed setting to which the fan controller 146 sets the fan 116 in response to the error in the pressure output signal 148 is the minimum fan speed setting. This provides at least some airflow 140 for combusting the gas 124 while avoiding potentially providing too great an airflow 140 for the flow of the gas 124 discharged through the output port 122.
Additionally, the fan controller 146 may set the fan speed setting of the fan 116 based on the pressure indicated by the pressure output signal 148. This may be done prior to igniting the discharged gas 124 using the pilot burner 110.
The fan controller 146 may use a mapping of detected pressures to fan speed settings, or an equivalent thereto (e.g., formula), that is stored in the memory 166 (
At 182, an error in the pressure output signal 148 is detected by the fan controller 146. The detected error may be a loss of reception of the pressure output signal 148 by the controller 146, or another error, such as those discussed above.
At 184, the fan controller 146 sets the fan speed setting of the fan 116 to a predetermined fan speed setting. In one embodiment, the predetermined fan speed setting is the minimum fan speed setting.
Subsequently, if the error in the pressure output signal 148 is resolved, the air-assist flare 100 returns to normal operation. Thus, the controller 146 processes the pressure output signal 148 to determine the corresponding fan speed setting for the fan 116 and sets the fan 116 to the corresponding fan speed setting to facilitate complete combustion of the gas 124 discharged through the output port 122.
Some embodiments of the present disclosure relate to the pressure sensor 147 and techniques for obtaining an accurate reading of the pressure of the flammable gas 124 within the pipes 126 and 108, which may be used to estimate the flow of the flammable gas 124 discharged through the output port 122 and the optimum fan speed setting for the fan 116 to completely combust the discharged gas 124.
In one embodiment, the pressure sensor 147 includes a pressure transducer 188 that converts the pressure sensed through the tap 149 into the pressure output signal 148, as indicated in
The flow of the gas 124 may be unstable in certain locations as it travels through the main pipe 126 and the gas feed pipe 108. When the air-assist flare 100 includes the coupling 152 that transitions the fluid pathway from the horizontal pipe 126 to the vertical pipe 108, and/or a coupling that transitions the fluid pathway from the larger diameter pipe 126 to the smaller diameter pipe 108, the flow of the gas 124 may become turbulent, as indicated in
In one embodiment, the tap 149 is extended to a location where the flow of the gas 124 is substantially laminar. For example, the tap 149 may extend through the coupling 152 into the main pipe 126 where the flow of the gas 124 is more laminar, such as a distance 190 of 10-24 inches, for example, upstream from the coupling 152 relative to the flow of the gas 124.
In one embodiment, the pressure sensor 147 includes a pitot tube 192 that is supported within the main pipe 126. The pitot tube 192 includes an impact pressure opening 194 that faces the flow of the gas 124. The tap 149 is coupled to the impact pressure opening 194 to receive the pressure at the impact pressure opening 194. With the pitot tube 192 positioned within the pipe 126 where the flow of the gas 124 is substantially laminar, the pressure output signal 148 produced by the transducer 188 is more stable and accurate than when the tap 149 extends into more turbulent flows of the gas 124.
In some embodiments, the fan controller 146 and pressure transducer 188 may be attached to and supported by the pipe 126, the pipe 108 and/or the coupling 152.
In one embodiment, the air-assist flare 100 includes a heat shield 200 that operates to shield the transducer 188 and the fan controller 146 from the heat of the burning gas 124 at the distal end 150 of the flare body 106. Thus, the heat shield 200 is positioned between the distal end 150 and the fan controller 146 and the transducer 188.
The heat shield 200 may be attached to a section of the air-assist flare 100, such as the flare body 106, the pipe 108, the pipe 126, or the coupling 152. In the example of
The conduit forming the tap 149 may include an elbow 206 that allows the transducer 188 and the controller 146 to be connected to a vertical section of conduit 208. In one embodiment, the tap 149 is connected to the conduit 208 through a bleed ring 210 and suitable fittings, as indicated in the isometric view of
In one embodiment, a valve 212 controls the exposure of the transducer 188 to the conduit that is connected to the tap 149. The valve 212 allows the tap 149 to be sealed in the event the transducer 188 and/or the controller 146 require servicing.
Although embodiments of the present disclosure have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the disclosed embodiments.
The present application is based on and claims the benefit of U.S. provisional patent application Ser. No. 63/506,916, filed Jun. 8, 2023, the content of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63506916 | Jun 2023 | US |
