A fuel gas flow regulation method and system for a flare pilot light

Abstract

The present application belongs to the technical field of high-acid gas field gas production, and particularly relates to a fuel gas flow regulation method and system for a flare eternal flame, which obtains the instantaneous fuel gas flow required by the flare through a natural gas instantaneous venting gas amount calculation formula and a fuel gas calculation formula; obtains the size of the flow-limiting nozzle required by the flare according to the obtained instantaneous fuel gas flow required by the flare and the corresponding relationship between the instantaneous fuel gas flow required by the flare and the size of the flow-limiting nozzle required for regulation; and selects the branch in which the flow-limiting nozzle corresponding to the size of the flow-limiting nozzle required is located according to the size of the flow-limiting nozzle required, and controls the branch to be turned on. The specific control information is calculated before regulation, and the control information is actually information for controlling the branch to be turned on or turned off, so as to control the branch to be turned on or turned off, and adjust the fuel gas flow of the flare eternal flame to the required flow value. Therefore, the method of the present application is simple and accurate in implementation process, and has low regulation difficulty and high regulation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of gas production technology for high-acid gas fields, specifically relating to a method and system for regulating the fuel gas flow of a flare lamp. Background Technology

[0002] The gas production station of the high acid gas field uses a fuel gas supply flare that burns continuously around the clock to ignite the high hydrogen sulfide gas (highly toxic) vented from the gas production station. The high hydrogen sulfide gas burns with oxygen in the air to produce carbon dioxide, sulfur dioxide (low toxicity) and water, thereby reducing the toxicity of the burning high hydrogen sulfide gas. The process can also be switched to purge pipelines containing high hydrogen sulfide gas to ensure the safety of station equipment, personnel and environment.

[0003] When operators enter the site to adjust the fuel gas, they must wear positive pressure air respirators for safety protection. Depending on the station conditions, weather, wind speed, and other factors, they must adjust the fuel gas flow rate for the flare burner in a timely manner. However, manual adjustment relies on experience to first determine whether to increase or decrease the fuel gas flow rate, and then slowly adjust the needle valve at the gas extraction station to limit the fuel gas flow. Therefore, manual control is inefficient. Furthermore, because the fuel gas pipeline into the flare burner is very long (approximately 300-400 meters), and for safety reasons, the needle valve limiting the fuel gas flow is located a considerable distance from the flare's fuel gas inlet on this pipeline. Therefore, adjusting the valve opening at this location results in a delay before it affects the flare's fuel gas inlet, further increasing the difficulty of adjustment. Thus, the process of manually adjusting the valve is very slow, and due to the delay in the adjustment result, the gas flow rate and velocity cannot be precisely controlled manually.

[0004] Therefore, the existing fuel gas flow control based on manual adjustment for flare lamps has the following problems: (1) The valve adjustment time is long and the operator's workload is high; (2) Because manual adjustment is not easy to control, when the valve opening is too large, the fuel gas consumption is too large, resulting in energy waste; when the valve opening is too small, the fuel gas flow is too small and it is blown out by wind, rain or strong airflow, which cannot ignite the high hydrogen sulfide natural gas, causing personal injury and environmental pollution. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for regulating the fuel gas flow rate of a torch lamp, in order to solve the problems of difficulty in control and high adjustment difficulty in existing methods based on manual adjustment of fuel gas flow rate.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for regulating the fuel gas flow rate of a torch lamp, comprising the following steps:

[0007] 1) Obtain the instantaneous flow rate of fuel gas required by the flare by using the instantaneous venting volume calculation formula of natural gas and the fuel gas calculation formula; the instantaneous venting volume calculation formula of natural gas is established based on the correspondence between natural gas parameters and venting pipeline parameters and instantaneous venting volume of natural gas, and the fuel gas calculation formula is established based on the correspondence between instantaneous venting volume of natural gas and instantaneous flow rate of fuel gas required by the flare.

[0008] 2) Based on the instantaneous flow rate of the flare required for fuel gas and the correspondence between the instantaneous flow rate of the flare required for fuel gas and the nozzle size of the flow-limiting nozzle required for regulation, the required nozzle size of the flow-limiting nozzle is obtained.

[0009] 3) Based on the required flow-limiting nozzle size, select the branch where the flow-limiting nozzle of that size is located, and control the conduction of this branch.

[0010] Its beneficial effects are as follows: To avoid the problems of high adjustment difficulty, low adjustment efficiency, and low adjustment accuracy associated with manually adjusting the fuel gas flow rate of the torch lamp, this invention first obtains the required fuel gas flow rate during the fuel gas quantity control process. Based on this calculated fuel gas flow rate, the control system obtains the required nozzle size and then selects the corresponding control branch to achieve the fuel gas quantity control process. This establishes a control system that can quickly and accurately switch between different flow rates, has a certain degree of versatility, and reduces workload. Furthermore, because the method of this invention only requires pre-calculation before adjustment to obtain specific control information—which is actually the information on whether the control branch is on or off—and based on this, the fuel gas flow rate of the torch lamp can be adjusted to the required flow rate value by controlling the branch to be on or off, the method of this invention is simple and accurate, with low adjustment difficulty and high adjustment efficiency.

[0011] Furthermore, the formula for calculating the instantaneous air release volume of the natural gas is as follows: ;in, This refers to the instantaneous air release rate of natural gas. The molar mass of the gas; The compressibility factor of natural gas at the cross section; To vent inlet temperature; The Mach number of the gas at the inlet cross section; To release the inlet pressure; This refers to the inner diameter of the venting pipeline. The isentropic index of the gas; is the gas constant.

[0012] Furthermore, the formula for calculating the fuel gas is as follows: ,in This represents the maximum instantaneous consumption of fuel gas required for the flare. These are preset parameters.

[0013] Furthermore, the correspondence between the instantaneous flow rate of the fuel gas required for the flare and the nozzle size of the flow-limiting nozzle needed for regulation is as follows:

[0014] ;

[0015] in, The diameter of the air nozzle; The relative density of natural gas; The insulation coefficient of natural gas; This is equivalent to the operating pressure before venting.

[0016] To address the aforementioned technical problems, this invention also provides a fuel gas flow control system for a torch continuously lit lamp, comprising a control system and a control branch connected in series. The control branch includes a first control device and a second control device connected in parallel. The first control device includes a first regulating valve and a first flow-limiting nozzle connected in series, and the second control device includes a second regulating valve and a second flow-limiting nozzle connected in series. The first and second flow-limiting nozzles have different nozzle sizes. The control system includes a memory and a processor. The processor executes instructions to implement the fuel gas flow control method for the torch continuously lit lamp described above, achieving the same beneficial effects as the method.

[0017] Furthermore, it also includes gate valves installed at the front and rear ends of the first flow-limiting nozzle, and gate valves installed at the front and rear ends of the second flow-limiting nozzle.

[0018] The system in this invention also has gate valves installed before and after the first flow-limiting nozzle, and gate valves installed before and after the second flow-limiting nozzle, so that when the flow-limiting nozzle malfunctions and needs to be replaced, the valves before and after the corresponding flow-limiting nozzle can be closed to repair or replace the nozzle.

[0019] Furthermore, the gate valve at the front end of the No. 1 flow-limiting nozzle and the gate valve at the front end of the No. 2 flow-limiting nozzle form a main valve, which is connected in series between the control system and the regulation system.

[0020] In this invention, a main valve is set between the control system and the control branch. This main valve is used for the switching of the entire system. That is, the gate valves at the same end of the first flow limiting nozzle and the second flow limiting nozzle are shared by the main valve. Compared with setting a gate valve at the front end of the first flow limiting nozzle and another gate valve at the front end of the second flow limiting nozzle, the system of this invention reduces the number of gate valves, thereby reducing the complexity of the system and the control complexity, and also reducing the cost of the system.

[0021] Furthermore, it also includes pressure gauges and thermometers installed on both the branch where the No. 1 control device is located and the branch where the No. 2 control device is located.

[0022] In this invention, pressure gauges and thermometers are installed in each branch to obtain pressure and temperature data of each branch.

[0023] Furthermore, the control branch also includes a manual control process, which is connected in parallel with the first control device and also in parallel with the second control device, so that when manual control is required, the control system can make the branch where the manual control process is located open; the manual control process includes a regulating valve for controlling the fuel gas flow rate of the branch where the manual control process is located.

[0024] The system of the present invention sets up the manual control process, the first control device, and the second control device in parallel. That is, the first control device, the second control device, and the manual control process are three branches in parallel. Specifically, the manual control process includes a regulating valve for manual adjustment. When it is necessary to manually increase the purging volume, the branch where the manual control process is located is controlled to be open. By manually adjusting the regulating valve in the manual control process, the fuel gas flow rate of the torch lamp reaches the required gas volume. Attached Figure Description

[0025] Figure 1 This is a flowchart of the calculation model for the fuel gas volume control system of the torch lamp of the present invention.

[0026] Figure 2 This is a schematic diagram of the fuel gas volume control system for the torch lamp of the present invention.

[0027] The system comprises: 1. Control system; 2. No. 1 regulating device; 3. Manual control process; 4. No. 2 regulating device; 5. No. 1 regulating valve; 6. No. 2 regulating valve; 7. No. 1 flow-limiting nozzle; 8. Regulating valve; 9. No. 2 flow-limiting nozzle; 10. No. 2 gate valve; 11. No. 1 gate valve; 12. Ball valve; and 13. Pressure regulating system. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] Example of a fuel gas flow control system for a torch lamp:

[0030] To avoid the problems of high adjustment difficulty, low adjustment efficiency, and low adjustment accuracy associated with manually adjusting the fuel gas flow of the torch lamp, the system in this embodiment designs a control system and at least two regulating devices, including flow-limiting nozzles, with multiple regulating devices connected in parallel. During the fuel gas flow regulation process, the system first obtains the required fuel gas flow through a fuel gas flow demand calculation model of the control system. Based on this calculated fuel gas flow, the control system obtains the required nozzle size and then selects the appropriate regulating branch for the corresponding control device to achieve the fuel gas flow regulation process.

[0031] like Figure 2 The diagram shown is a system structure diagram of this embodiment. The system in this embodiment is located at the front end of the fuel gas pipeline into the flare. Specifically, it includes a control system 1 and a regulating branch connected in series. The regulating branch in this embodiment includes a first regulating device 2 and a second regulating device 4 connected in parallel. The first regulating device 2 includes a first regulating valve 5 and a first flow-limiting nozzle 7 connected in series. The control system 1 controls the on / off state of the first regulating device and the fuel gas flow rate when it is on by controlling the first regulating valve 5. The second regulating device 4 includes a second regulating valve 6 and a second flow-limiting nozzle 9 connected in series. The control system 1 controls the on / off state of the second regulating device 4 and the fuel gas flow rate when it is on by controlling the second regulating valve 6. Furthermore, the nozzle sizes of the first and second flow-limiting nozzles in this embodiment are different; the nozzle size of the first flow-limiting nozzle is larger than that of the second flow-limiting nozzle. The nozzle size range of the first flow-limiting nozzle is 5~8mm, and the nozzle size range of the second flow-limiting nozzle is 1~3mm.

[0032] In this embodiment, the No. 1 control device 2 is used when the flare lamp requires a larger gas supply. Upon receiving a control signal, the No. 1 control device switches the process to the No. 1 control device, accurately increasing the gas volume to the required flow rate through the flow-limiting nozzle. The No. 2 control device 4 is used to supply the minimum continuous gas volume for daily combustion of the flare lamp. That is, when the flare lamp control system is in normal operation, the control system 1 performs model calculations and switches the process to the No. 2 control device. The No. 2 regulating valve 6 and the No. 2 gate valve 10 are in the open state, while the regulating valve 8, the No. 1 regulating valve 5, and the No. 1 gate valve 11 are in the closed state. The fuel gas provides the minimum continuous gas volume to the flare lamp through the flow-limiting nozzle 9 and the pressure regulating system 13, ensuring the good operating condition of the flare lamp. When severe weather is detected and rapid adjustment of the flare gas flow is required, control system 1 performs model calculations and switches the process to control device 1. Control valve 5 and gate valve 11 are open, while control valve 8, control valve 6, and purge inlet ball valve 12 are closed. Through the flow-limiting nozzle 7, the gas flow rapidly increases and precisely reaches a stable flow rate. Control system 1 acquires the instantaneous flow rate of the flare gas required during venting and, based on this instantaneous flow rate, obtains the nozzle size value of the corresponding flow-limiting nozzle under these conditions. Then, using the calculated nozzle size value, it selects the corresponding control device, activating the branch containing that control device, thereby achieving rapid and accurate control of the fuel gas flow reaching the flare gas inlet.

[0033] In this embodiment, the system also has gate valves installed before and after the first flow-limiting nozzle 7, and gate valves installed before and after the second flow-limiting nozzle 9, respectively. This allows for the closure of the corresponding valves before and after the flow-limiting nozzle to facilitate repair and replacement when the nozzle malfunctions and needs replacement. The specific locations of the gate valves are as follows: Figure 2 As shown, a main valve is installed between the control system 1 and the control branch. This main valve is used for the switching of the entire system. Specifically, the gate valves on the same end of the flow-limiting nozzle 7 (No. 1) and flow-limiting nozzle 9 (No. 2) are shared by the main valve. The gate valve on the other end of flow-limiting nozzle 7 is gate valve 11, and the gate valve on the other end of flow-limiting nozzle 9 is gate valve 10. When flow-limiting nozzle 7 malfunctions, it is replaced by closing the main valve and gate valve 11. Similarly, when flow-limiting nozzle 9 malfunctions, it is replaced by closing the main valve and gate valve 10.

[0034] In this embodiment, the system also has pressure gauges installed on both the branch where the first control device 2 is located and the branch where the second control device 4 is located (e.g., Figure 2 PG in the middle) and thermometers (such as Figure 2 The TI in the pressure gauge and thermometer is used to obtain pressure and temperature data for each branch.

[0035] The control branch in this embodiment also includes a manual control process 3, which is connected in parallel with both the first and second control devices. Specifically, the first and second control devices, along with the manual control process, form three parallel branches. The manual control process 3 includes a regulating valve 8 for manual adjustment. When a manual increase in purging volume is required, the control device closes the second regulating valve 6, the second gate valve 10, the first regulating valve 5, and the first gate valve 11, while opening the regulating valve 8 and the inlet ball valve 12. This allows fuel gas to enter the manual control process 3, achieving the required gas volume through manual adjustment. By retaining the manual control branch, it can be activated to achieve the corresponding control when manual control is needed.

[0036] Based on the system of this embodiment, the specific process of the fuel gas quantity control method for the flare lamp includes:

[0037] 1) Obtain the required nozzle size based on real-time data;

[0038] like Figure 1 As shown, the control system 1 mainly selects the size of the flow-limiting nozzle based on the nozzle and fuel gas flow demand model.

[0039] Natural gas venting requires consideration of frictional adiabatic processes during the venting process. Hydraulic calculations should employ the Van Noe equation for one-dimensional flow of compressible fluids with frictional adiabatic properties. Therefore, this embodiment first uses the instantaneous venting volume and fuel gas calculation formulas to calculate the instantaneous venting volume of natural gas:

[0040] ;

[0041] in, This represents the instantaneous air release rate of natural gas, expressed in kg / s. This represents the molar mass of the gas, expressed in kg / mol. The compressibility factor of natural gas at the cross section; The vent inlet temperature is expressed in Kelvin (K). The inlet cross-section gas Mach number is 0.5 in this embodiment; The pressure at the vent inlet is measured in MPa. This refers to the inner diameter of the venting pipeline, in mm. The isentropic index of the gas is taken as 1.23 in this embodiment; is a gas constant, with units of kJ / (kg·K); where M is based on the composition of high-sulfur natural gas, and is taken as 21.27 in this embodiment; The value was calculated using the GERG-2008 equation in software, and was taken as 0.82 for high-sulfur natural gas components. Based on the composition of high-sulfur natural gas, the value is 466.19;

[0042] Secondly, based on the instantaneous flow rate of fuel gas required by the flare during the venting period. The calculation is as follows:

[0043] ;

[0044] in These are preset parameters, and they vary depending on the weather conditions. Different values ​​are used to correct the amount of fuel gas.

[0045] The method used in this embodiment The specific values ​​are shown in Table 1 below:

[0046] Table 1

[0047] Serial Number Sunny weather Gale force below level 5 Gale force of level 5 or above <![CDATA[1×10 -4 ]]> <![CDATA[5×10 -4 ]]> <![CDATA[8×10 -4 ]]>

[0048] Finally, use the valve size calculation formula to calculate the valve size:

[0049] ;

[0050] in, This refers to the nozzle diameter, in mm. This represents the maximum instantaneous consumption of fuel gas required for the flare. The compressibility factor of natural gas at the cross section; The vent inlet temperature is expressed in Kelvin (K). The relative density of natural gas is given by 0.74 for high-sulfur natural gas. The adiabatic coefficient of natural gas is 1.3 for polyatomic natural gas containing hydrogen sulfide. The instantaneous gas volume at the initial venting, i.e. This is equivalent to the operating pressure before venting.

[0051] 2) Based on the obtained nozzle size, select one of the first and second control devices to conduct, and control the other to block. That is, the system automatically selects a suitable flow-limiting nozzle and transmits the signal to the valve through the control system to achieve rapid process switching. Specifically, when the nozzle size calculated in step 1) does not exceed the set value, the second control device is selected to conduct, and the first control device is controlled to block. When the nozzle size calculated in step 1) exceeds the set value, the first control device is selected to conduct, and the second control device is controlled to block.

[0052] The system design of this embodiment is simple and easy to operate. Through the torch lamp control system, it solves the problems of inaccurate fuel gas volume control, fuel gas energy waste, or insufficient fuel gas flow that can be blown out by wind, rain, or strong air currents, making it impossible to ignite natural gas with high hydrogen sulfide content, causing personal injury and environmental pollution. It achieves the effects of reducing control time, reducing labor intensity, and saving energy and protecting the environment.

[0053] Example of a method for regulating the fuel gas flow rate of a torch lamp:

[0054] The method in this embodiment obtains the instantaneous flow rate of fuel gas required by the flare using the formulas for calculating the instantaneous venting volume of natural gas and the fuel gas. Based on the obtained instantaneous flow rate of fuel gas required by the flare and the correspondence between the instantaneous flow rate of fuel gas required by the flare and the nozzle size of the flow-limiting nozzle needed for regulation, the required nozzle size is obtained. According to the required nozzle size, the branch containing the flow-limiting nozzle of that size is selected, and this branch is controlled to be connected. Specifically, the fuel gas flow rate regulation method for the flare starter can be implemented through a fuel gas flow rate regulation system for the flare starter. The process of implementing the fuel gas flow rate regulation method for the flare starter has been described in detail in the embodiment of the fuel gas flow rate regulation system for the flare starter, and will not be repeated here.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A method for regulating the fuel gas flow rate of a torch lamp, characterized in that, Includes the following steps: 1) Obtain the instantaneous flow rate of fuel gas required by the flare by using the instantaneous venting volume calculation formula of natural gas and the fuel gas calculation formula; the instantaneous venting volume calculation formula of natural gas is established based on the correspondence between natural gas parameters and venting pipeline parameters and instantaneous venting volume of natural gas, and the fuel gas calculation formula is established based on the correspondence between instantaneous venting volume of natural gas and instantaneous flow rate of fuel gas required by the flare. 2) Based on the instantaneous flow rate of the flare required for fuel gas and the correspondence between the instantaneous flow rate of the flare required for fuel gas and the nozzle size of the flow-limiting nozzle required for regulation, the required nozzle size of the flow-limiting nozzle is obtained. 3) Based on the required flow-limiting nozzle size, select the branch where the flow-limiting nozzle of that size is located, and control the conduction of this branch.

2. The method for regulating the fuel gas flow rate of the torch lamp according to claim 1, characterized in that, The formula for calculating the instantaneous air release rate of natural gas is as follows: ;in, This refers to the instantaneous air release rate of natural gas. The molar mass of the gas; The compressibility factor of natural gas at the cross section; To vent inlet temperature; The Mach number of the gas at the inlet cross section; To release the inlet pressure; This refers to the inner diameter of the venting pipeline. The isentropic index of the gas; is the gas constant.

3. The method for regulating the fuel gas flow rate of the torch lamp according to claim 2, characterized in that, The formula for calculating the fuel gas is: ,in This represents the maximum instantaneous consumption of fuel gas required for the flare. These are preset parameters.

4. The method for regulating the fuel gas flow rate of the torch lamp according to claim 3, characterized in that, The relationship between the instantaneous flow rate of fuel gas required for the flare and the nozzle size of the flow-limiting nozzle needed for regulation is as follows: ； in, The diameter of the air nozzle; The relative density of natural gas; The insulation coefficient of natural gas; This is equivalent to the operating pressure before venting.

5. A fuel gas flow control system for a torch continuously lit lamp, characterized in that, The system includes a control system and a control branch connected in series. The control branch includes a first control device and a second control device connected in parallel. The first control device includes a first regulating valve and a first flow-limiting nozzle connected in series. The second control device includes a second regulating valve and a second flow-limiting nozzle connected in series. The nozzle sizes of the first and second flow-limiting nozzles are different. The control system includes a memory and a processor. The processor is used to execute instructions to implement the fuel gas flow control method for the torch lamp as described in any one of claims 1 to 4.

6. The fuel gas flow control system for the torch's continuous flame according to claim 5, characterized in that, It also includes gate valves installed at the front and rear ends of the No. 1 flow-limiting nozzle, and gate valves installed at the front and rear ends of the No. 2 flow-limiting nozzle.

7. The fuel gas flow control system for the torch's continuous flame according to claim 6, characterized in that, The gate valve at the front end of the No. 1 flow-limiting nozzle and the gate valve at the front end of the No. 2 flow-limiting nozzle form a main valve, which is connected in series between the control system and the regulation system.

8. The fuel gas flow control system for the torch's continuous flame according to claim 5, characterized in that, It also includes pressure gauges and thermometers installed on both the branch where the No. 1 control device is located and the branch where the No. 2 control device is located.

9. The fuel gas flow control system for the torch's continuous flame according to claim 5, characterized in that, The control branch also includes a manual control process, which is connected in parallel with the first control device and also in parallel with the second control device, so that when manual control is required, the control system can make the branch where the manual control process is located open; the manual control process includes a regulating valve for controlling the fuel gas flow rate of the branch where the manual control process is located.

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