Monitoring and maintaining flare head temperature

Abstract

A data stream indicative of a first set of flare head parameters is received. A second set of parameters is determined based on the first set of flare head parameters. A control signal is transmitted to the actuatable device based on the first set of parameters and the second set of parameters. The actuatable device is configured to maintain at least one parameter of the first set of parameters and the second set of parameters within a specified range.

Description

[0001] Priority claim

[0002] This application claims priority to U.S. patent application No. 17 / 811,219, filed on July 7, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to flare tip monitoring. Background Art

[0004] During hydrocarbon production and processing, flare tips are used to safely burn excess hydrocarbons during production or process upsets. The flare tips are mounted at sufficient height and distance to reduce radiation exposure to workers and to reduce the potential for ignition of atmospheric hydrocarbons, as the flare tip is a potential ignition source. The flame at the flare tip burns at a temperature high enough that the flame cannot usually be measured directly. Summary of the invention

[0005] This disclosure describes techniques related to monitoring and maintaining flare tip temperature.

[0006] An exemplary embodiment of the subject matter described within the present disclosure is a method having the following features. A data stream indicating a first set of flare tip parameters is received. A second set of parameters is determined based on the first set of flare tip parameters. A control signal is sent to an actuatable device based on the first set of parameters and the second set of parameters. The actuatable device is configured to maintain at least one of the first set of parameters and the second set of parameters within a specified range.

[0007] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following.A first set of parameters includes a flare mass flow rate and a flare mass flow composition.

[0008] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following.A second set of parameters includes adiabatic flame temperature or theoretical flame temperature.

[0009] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following. Determining the second set of parameters includes: determining an adiabatic flame temperature. The adiabatic flame temperature is determined by the following equation:

[0010] T ad =T ⊕ +LHV molar / ΣV i C pi

[0011] Where T ad is the adiabatic flame temperature in degrees Kelvin (K), T ⊕is 298 K, LHV molar is the lower heating value of the mass flow component in moles, V i is the molar coefficient, and C pi is the molar heat capacity.

[0012] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following. Determining the second set of parameters includes: determining a theoretical flame temperature. The theoretical flame temperature is determined by the following equation:

[0013]

[0014] where T is the temperature in degrees Fahrenheit, NHV is the net heating value of the hydrocarbon stream per pound of excess air in British thermal units, and where .

[0015] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following: Determine a forecast of steam usage. The forecast of steam usage is determined by the following equation:

[0016] W(steam)=W[0.68-(10.8 / MW)]

[0017] Where W (steam) is the flow rate of steam in pounds per hour, W is the flow rate of combustion gases, and where MW is the molecular weight of the hydrocarbon gas in the mass flow in pounds per pound mole.

[0018] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following: Steam flow is regulated by a control signal. The control signal is determined based on a prediction of the steam usage.

[0019] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following: The actuatable device is a blower, and actuation of the blower is controlled by a control signal.

[0020] Aspects of the exemplary method that may be combined with the exemplary method alone or with other aspects include the following: Values ​​of the first set of parameters and the second set of parameters are stored in a database.

[0021] An exemplary embodiment of the subject matter described within the present disclosure is a flare system having the following features. A flare header directs flare gas to a flare head. An actuatable device is arranged and configured to add a mass flow rate to a flare flow flowing through the flare header toward the flare head. A controller is coupled to the actuatable device. The controller is configured to receive a data stream indicating a first set of flare head parameters. The controller is configured to determine a second set of parameters based on the first set of flare head parameters. The controller is configured to send a control signal to the actuatable device based on the first set of parameters and the second set of parameters. The actuatable device is configured to maintain at least one of the first set of parameters and the second set of parameters within a specified range.

[0022] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following.The actuatable device includes a steam supply.

[0023] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following.The actuatable device includes a blower.

[0024] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following.A first set of parameters includes flare mass flow rate and flare mass flow composition.

[0025] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following.A second set of parameters includes adiabatic flame temperature or theoretical flame temperature.

[0026] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following. Determining the second set of parameters includes: determining an adiabatic flame temperature. The adiabatic flame temperature is determined using the following equation:

[0027] T ad =T ⊕ +LHV molar / ΣV i C pi

[0028] Where T ad is the adiabatic flame temperature in degrees Kelvin (K), T ⊕ is 298 K, LHV molar is the lower heating value of the mass flow component in moles, V i is the molar coefficient, and C pi is the molar heat capacity.

[0029] Aspects of the example flare system that may be combined with the example flare system alone or with other aspects include the following. Determining the second set of parameters includes: determining a theoretical flame temperature. The theoretical flame temperature is determined by the following equation:

[0030]

[0031] where T is the temperature in degrees Fahrenheit, NHV is the net heating value of the hydrocarbon stream per pound of excess air in British thermal units, and where .

[0032] Specific embodiments of the subject matter described in this disclosure can be implemented to achieve one or more of the following advantages. The subject matter described herein allows for flare monitoring and extended flare service life. In addition, the subject matter described herein can help enhance combustion and smokeless operation. Such enhancements can reduce the steam and air required for flare operation, thereby reducing the energy required for flare combustion and utility sources (e.g., steam and air) and the associated CO2.

[0033] The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of an example flare system.

[0035] Figure 2 is a schematic diagram of an example controller that may be used with aspects of the present disclosure.

[0036] Figure 3 is a flow chart of an exemplary method that can be used with aspects of the present disclosure.

[0037] Like reference numbers and designations in the various drawings represent like elements. DETAILED DESCRIPTION

[0038] Heat intensity, thermal cycling, and smoke generation are all factors that affect the resulting life of the flare tip. Monitoring flare tip characteristics during operation and actively maintaining those characteristics can extend the life of the flare tip compared to running the flare without monitoring.

[0039] The present disclosure relates to such monitoring practices. For example, a flare tip temperature is monitored based on a first set of flare parameters. The first set of flare parameters is used to determine a second set of flare parameters. Then, an actuatable device is controlled based on the first set of parameters and the second set of parameters to maintain the flare tip within a specified operating range.

[0040] Figure 1is a schematic diagram of an example flare system 100. The flare system 100 includes a flare header 102 that feeds into a knockout tank 104. The knockout tank 104 allows liquid to flow out of the flare header 102 before the gas in the flare header 102 moves to a flare supply line 106. The flare supply line 106 supplies the flare gas to a flare tip 108 where the flare gas is ignited and burned by a flare flame 110. The flare tip 108 is located at a sufficient height and distance from workers to reduce the risk of radiation burns from the flare flame 110. The flare tip 108 itself is designed for a specific range of fuel consumption rates (e.g., flare gas), fuel composition, and temperature. In some cases, exceeding these specified ranges can shorten the life of the flare tip 108.

[0041] In some embodiments, the flare system 100 includes an actuatable device 112 that is arranged and configured to add mass flow to the flare flow flowing through the flare header 102 toward the flare tip 108. The additional mass flow is used to adjust the temperature of the flare flame 110, reduce smoke from the flare tip 108, or a combination of both. Examples of such actuatable devices 112 include steam supplies and blowers. In some embodiments, such actuatable devices are controlled by a controller 114.

[0042] Within the flare header 102 of the flare supply line 106 is a flow meter 116 that is used in conjunction with the known composition of the flare gas to measure or determine the mass flow rate. That is, the flow meter 116 sends a signal or data stream indicative of the mass flow rate. The flow meter 116 is coupled to the controller 114. In some embodiments, the composition of the flare gas is determined by periodic testing or using an online gas chromatograph 118. In embodiments where an online gas chromatograph 118 is used, the online gas chromatograph 118 sends a signal or data stream indicative of the mass flow composition of the flare gas.

[0043] Figure 2 1 is a schematic diagram of an example controller that may be used with various aspects of the present disclosure. The controller 114 may monitor system parameters, among other things, and send signals to initiate and / or adjust various operating parameters of the flare system 100. Figure 2As shown, in some cases, the controller 114 includes a processor 250 (e.g., implemented as one or more processors) and a memory 252 (e.g., implemented as one or more memories), the memory 252 containing instructions for causing the processor 250 to perform operations described herein. The processor 250 is coupled to an input / output (I / O) interface 254 for sending and receiving communications with components in the system, including, for example, sensors such as the flow meter 116 or the gas chromatograph 118, or a remote database 202 storing values ​​of the first set of parameters or the second set of parameters. In some cases, the controller 114 can additionally communicate status with one or more of the various system components of the flare system 100 (including actuator systems, such as the actuatable device 112) and other sensors provided in the flare system 100 (e.g., pressure sensors, temperature sensors, vibration sensors, and other types of sensors), and send actuation and / or control signals thereto. In some cases, the controller 114 can communicate status and send actuation and control signals to one or more components within the flare system 100 (such as the actuatable device 112). Communications may be hardwired, wireless, or a combination of hardwired and wireless. In some embodiments, controllers similar to controller 114 may be located elsewhere, such as in a data truck, elsewhere in the field, or even remotely from the field. In some embodiments, controller 114 may be a distributed controller with different parts located near or off-site. For example, in some cases, controller 114 may be located near components of system 100, or it may be located in a separate control room or data truck. Additional controllers may be used throughout the field as stand-alone controllers or networked controllers without departing from the present disclosure.

[0044] The controller 114 can operate in monitoring, commanding, and using the system 100 to monitor and regulate the condition of the flare tip 108. To monitor and control the system 100, the controller 114 is used in conjunction with sensors 116 and 118. The input and output signals controlled and monitored by the controller 114, including data from the sensors, can be continuously recorded by the controller 114.

[0045] The controller 114 may have different levels of autonomy for controlling the system 100. For example, the controller 114 may begin sensing parameters indicative of smoke generation or high temperatures at the flare tip, and the operator adjusts the actuatable device 112, for example by changing the airflow rate of the blower or the steam injection rate. Alternatively, the controller 114 may begin sensing these parameters, receive additional input from the operator, and begin adjusting the actuatable device 112 without further input from the operator. Alternatively, the controller 114 may begin sensing the parameters and adjust the actuatable device 112 without input from the operator.

[0046] In operation, a controller 114 coupled to the actuatable device 112 receives a data stream indicative of a first set of flare tip parameters, such as a mass flow rate of the flare gas or a composition of the flare gas. The controller 114 also determines a second set of parameters based at least in part on the first set of flare tip parameters, such as a flare temperature (adiabatic or theoretical). The controller 114 then sends a control signal to the actuatable device 112 based on the first set of parameters and the second set of parameters. The actuatable device 112 is configured to maintain or adjust at least one of the first set of parameters and the second set of parameters within a specified range, for example, the flare temperature may be adjusted by changing the amount of steam or air added to the flare flow.

[0047] Figure 3 300 is a flow chart of an exemplary method 300 that can be used with aspects of the present disclosure. In some embodiments, all or part of the following method steps are performed by the controller 114. At 302, a data stream indicating a first set of flare tip parameters is received. In some embodiments, the first set of parameters includes a current flare mass flow rate, a current flare mass flow composition, a specified range of fuel consumption rate (e.g., flare gas), a specified range of fuel composition, and a specified range of flare tip temperature (adiabatic or theoretical).

[0048] At 304, a second set of parameters is determined based in part on the first set of flare tip parameters. In some embodiments, the second set of parameters includes an adiabatic flame temperature, a theoretical flame temperature, or both. In the case of determining an adiabatic flame temperature, the adiabatic flame temperature is determined by the following equation:

[0049] T ad =T ⊕ +LHV molar / ΣViC pi Equation (1)

[0050] Where T ad is the adiabatic flame temperature in degrees Kelvin (K), T ⊕ is 298 K, LHV molar is the lower heating value of the mass flow component in moles, V i is the molar coefficient, and C pi is the molar heat capacity. In some embodiments, LHV molar 、V i and C pi Determined based on the composition of the mass flow.

[0051] In an embodiment where the theoretical flame temperature is determined, the theoretical flame temperature is determined by the following equation:

[0052] Equation (2)

[0053] where T is the temperature in degrees Fahrenheit, NHV is the net heating value of the hydrocarbon stream per pound of excess air in British Thermal Units, and where EA is determined by the following equation:

[0054] Equation (3)

[0055] Where Y is the dry mole percent of O2.

[0056] In some embodiments, the values ​​of the first set of parameters, the second set of parameters, or both are stored in a database 202 or a lookup table. In such embodiments, the database can be located in various locations, for example, locally on the memory 252 of the controller 114, remotely at a separate location, or in a separate memory at the flare site.

[0057] At 306, based on the first set of parameters and the second set of parameters, a control signal is sent, for example, from the controller 114 to the actuatable device 112. The actuatable device 112 is configured to maintain or adjust at least one of the first set of parameters or the second set of parameters within a specified range (based on the control signal). For example, additional steam or air may be added to the mass flow supplied to the flare tip to adjust smoke production, flare temperature, or both.

[0058] In embodiments using steam, steam usage is predicted using the following equation:

[0059] W(steam)=W[0.68-(10.8 / MW)] Equation (4)

[0060] Where W is the flow rate of the flare gas in pounds per hour, W(steam) is the flow rate of the steam, and where MW is the molecular weight of the hydrocarbon gas in the mass flow in pounds per pound mole. In some embodiments, the steam flow is regulated by a controller, more specifically, by a control signal sent from the controller 114 to the steam source. Alternatively or additionally, the actuatable device includes a blower. In such embodiments, the air flow rate of the blower is regulated by the controller 114, more specifically, by a control signal sent by the controller 114 to the blower.

[0061] Although the present disclosure contains many specific implementation details, these details should not be interpreted as limitations on the scope of the claimed protection, but rather as descriptions of features specific to a particular embodiment. Certain features described in the present disclosure in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination. In addition, although the above-mentioned features may be described as functioning in certain combinations, and may even be initially claimed as such, in some cases one or more features in the claimed combination may be deleted from the combination, and the claimed combination may point to a sub-combination or a variation of a sub-combination.

[0062] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that the operations be performed in the particular order or sequential order shown, or that all of the illustrated operations be performed to achieve the desired results. In addition, the separation of various system components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the components and systems described can generally be integrated into a single product or packaged into multiple software products.

[0063] Thus, certain embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. Furthermore, the processes described in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve desirable results.

Claims

1. A method comprising: receiving a data stream indicative of a first set of flare tip parameters; determining a second set of parameters based on the first set of flare tip parameters; and A control signal is sent to an actuatable device based on the first set of parameters and the second set of parameters, the actuatable device being configured to maintain at least one of the first set of parameters and the second set of parameters within a specified range.

2. The method of claim 1, wherein the first set of parameters comprises: flare mass flow rate; and Flare mass flow composition.

3. The method of claim 2, wherein the second set of parameters includes an adiabatic flame temperature or a theoretical flame temperature.

4. The method of claim 3, wherein determining the second set of parameters comprises: Determine the adiabatic flame temperature, wherein the adiabatic flame temperature is determined using the following equation: T ad =T ⊕ +LHV molar / ΣV i C pi Where T ad is the adiabatic flame temperature in degrees Kelvin (K), T ⊕ is 298 K, LHV molar is the lower heating value of the mass flow component in moles, V i is the molar coefficient, and C pi is the molar heat capacity.

5. The method of claim 3, wherein determining the second set of parameters comprises: A theoretical flame temperature is determined, wherein the theoretical flame temperature is determined by the following equation: where T is the temperature in degrees Fahrenheit, NHV is the net heating value of the hydrocarbon stream per pound of excess air in British thermal units, and where .

6. The method of claim 2, further comprising: A forecast of steam usage is determined, wherein the forecast of steam usage is determined by the following equation: W(steam)=W[0.68-(10.8 / MW)] where W (steam) is the flow rate of steam in pounds per hour, and where MW is the molecular weight of the hydrocarbon gas in the mass flow in pounds per pound mole.

7. The method of claim 6, wherein steam flow is regulated by a control signal determined based on a prediction of the steam usage.

8. The method of claim 1, wherein the actuatable device is a blower, actuation of the blower being controlled by the control signal.

9. The method of claim 1, further comprising: The values ​​of the first set of parameters and the second set of parameters are stored in a database.

10. A flare system, comprising: Torch head; a flare header directing flare gas to the flare tip; an actuatable device arranged and configured to add mass flow to a flare stream flowing through the flare header toward the flare tip; and a controller coupled to the actuatable device, the controller being configured to: receiving a data stream indicative of a first set of flare tip parameters; determining a second set of parameters based on the first set of flare tip parameters; and A control signal is sent to an actuatable device based on the first set of parameters and the second set of parameters, the actuatable device being configured to maintain at least one of the first set of parameters and the second set of parameters within a specified range.

11. The flare system of claim 10, wherein the actuatable device comprises a steam supply.

12. The flare system of claim 10, wherein the actuatable device comprises a blower.

13. The flare system of claim 10, wherein the first set of parameters comprises: flare mass flow rate; and Flare mass flow composition.

14. The flare system of claim 10, wherein the second set of parameters includes an adiabatic flame temperature or a theoretical flame temperature.

15. The flare system of claim 14, wherein determining the second set of parameters comprises: Determine the adiabatic flame temperature, wherein the adiabatic flame temperature is determined using the following equation: T ad =T ⊕ +LHV molar / ΣV i C pi Where T ad is the adiabatic flame temperature in degrees Kelvin (K), T ⊕ is 298 K, LHV molar is the lower heating value of the mass flow component in moles, V i is the molar coefficient, and C pi is the molar heat capacity.

16. The flare system of claim 14, wherein determining the second set of parameters comprises: A theoretical flame temperature is determined, wherein the theoretical flame temperature is determined by the following equation: where T is the temperature in degrees Fahrenheit, NHV is the net heating value of the hydrocarbon stream per pound of excess air in British thermal units, and where .

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