Oil-gas co-combustion control system for heat-conducting oil furnace in oil field

Abstract

The invention discloses an oil-gas co-combustion control system for an oil field heat-conducting oil furnace, and relates to the technical field of oil exploitation. The system comprises a combustion-supporting air door actuator, an atomization air door actuator, a fuel oil inlet regulating valve, a fuel oil return regulating valve, a PLC (programmable logic controller), a fuel oil pressure transmitter, a medium temperature transmitter, a combustor, an upper computer, a gas flow regulating valve and the like. A medium temperature signal serves as a main variable, the system can adjust distribution of fuel and air volume in real time, and automatic switching of three operation modes of fuel oil, fuel gas and oil-gas co-combustion is achieved. The optimal design of the combustor comprises a spiral heating pipe and a rotary shifting plate structure, so that the combustion efficiency and the heat conduction efficiency are improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil exploitation, in particular to an oil-gas mixed combustion control system for a heat-conducting oil furnace in an oil field. Background Art

[0002] In traditional oilfield production, associated gas is usually vented directly or burned in a simple flare due to its low yield. This method not only wastes precious energy, but also pollutes the atmospheric environment. Traditional thermal oil boilers usually only support a single fuel, such as oil or gas, lack flexible selection of fuel types, and cannot be adjusted according to actual working conditions and fuel supply conditions. This leads to low energy utilization efficiency and inability to fully utilize available resources such as associated gas. Summary of the invention

[0003] In order to overcome the defects of the above-mentioned prior art, the present invention provides the following technical solutions: a control system for oil-gas mixed combustion of a thermal oil furnace in an oilfield, comprising a combustion-supporting damper actuator, an atomizing damper actuator, a fuel inlet regulating valve, a fuel return regulating valve, a PLC controller, a fuel pressure transmitter, a medium temperature transmitter, a burner, a host computer and a gas flow regulating valve; the start and stop and load regulation of the control system for oil-gas mixed combustion of the thermal oil furnace in the oilfield are controlled by the medium temperature transmitter.

[0004] Preferably, the medium temperature signal is used as the main variable of the system, and the gas flow regulating valve or the fuel inlet regulating valve and the fuel return regulating valve are adjusted through the PLC controller to distribute the fuel and air volume.

[0005] Preferably, the system air volume control has two damper actuators, one of which is a combustion-supporting damper actuator and the other is an atomizing damper actuator. The system automatically adjusts the two damper actuators according to the load input.

[0006] Preferably, in the mixed combustion mode, when the gas volume cannot meet the load requirement, the mode is manually switched to the oil supplement combustion mode.

[0007] Preferably, the burner includes a combustion chamber, in which a first spiral heating tube and a second spiral heating tube are arranged in a spiral and cross-shaped manner. The bottom of the combustion chamber is provided with a conical bottom surface, and a bottom recovery nozzle is provided at the lowest point of the conical bottom surface for recovering incompletely burned fuel.

[0008] Preferably, a rotating paddle plate top bracket and a rotating paddle plate bottom bracket are respectively fixed to the top of the inner wall of the combustion chamber and the conical bottom surface, and a plurality of rotating paddle plates arranged in a circular array are rotatably mounted between the rotating paddle plate top bracket and the rotating paddle plate bottom bracket.

[0009] Preferably, a feeding pipe is provided at the rotation axis position of all the rotating dial plates, and there are at least two feeding pipes, which are used to provide fuel oil and gas respectively.

[0010] Preferably, a top cone cover is fixed on the top of the combustion chamber, an exhaust passage is fixed on the top of the top cone cover, a gas turbine is rotatably installed inside the exhaust passage, and the gas turbine and all rotating plates are fixedly matched through a transmission frame rod.

[0011] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention makes full use of the energy that would otherwise be wasted by using the associated gas generated during the oil field production process as one of the fuels. In the traditional method, the associated gas is usually directly burned or vented due to its low yield, which not only wastes energy but also causes environmental pollution. After adopting the present system, the associated gas is effectively used in the combustion process, reducing the dependence on external fuels, reducing energy consumption and emissions, and achieving the dual goals of efficient resource utilization and environmental protection; (2) The present invention supports three operating modes: fuel oil, gas, and oil and gas mixed combustion, and can be switched according to the associated gas supply and load demand. When the gas supply is sufficient, the gas mode is preferred; when the gas is insufficient to meet the load demand, it is switched to the mixed combustion mode and fuel oil is supplemented; (3) The burner of the present invention is provided with first and second spiral heating tubes arranged in a spiral cross, and a rotatable dial plate structure. The rotating dial plate rotates under the impetus of the high-temperature and high-pressure gas, so that the fuel is subjected to centrifugal force and is more evenly distributed around the inner wall of the combustion chamber. This design improves the combustion efficiency of the fuel. At the same time, the spiral heating tube can absorb more heat, improve the heat conduction efficiency, and ensure that the medium temperature quickly reaches and stabilizes within the set range. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural block diagram of the control system of the present invention.

[0013] Figure 2 It is a schematic diagram of the external structure of the combustion chamber of the present invention.

[0014] Figure 3 It is a schematic diagram of the internal structure of the combustion chamber of the present invention.

[0015] Figure 4 It is a schematic diagram of the structure of the spiral heating tube of the present invention.

[0016] In the figure: 1-combustion-supporting damper actuator; 2-atomizing damper actuator; 3-fuel inlet regulating valve; 4-fuel return regulating valve; 5-PLC controller; 6-fuel pressure transmitter; 7-medium temperature transmitter; 8-burner; 9-host computer; 10-gas flow regulating valve; 11-combustion chamber; 12-top cone cover; 13-exhaust channel; 14-gas turbine; 15-transmission frame rod; 16-rotating dial plate top bracket; 17-rotating dial plate; 18-rotating dial plate bottom bracket; 19-feeding pipe; 20-bottom recovery nozzle; 21-conical bottom surface; 22-first spiral heating tube; 23-second spiral heating tube. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1-Figure 4 , and further illustrate the technical solution of the present invention through specific implementation methods.

[0018] The present invention provides an oilfield thermal oil furnace oil-gas mixed combustion control system, comprising a combustion-supporting damper actuator 1, an atomizing damper actuator 2, a fuel inlet regulating valve 3, a fuel return regulating valve 4, a PLC controller 5, a fuel pressure transmitter 6, a medium temperature transmitter 7, a burner 8, a host computer 9 and a gas flow regulating valve 10; the start and stop and load regulation of the oilfield thermal oil furnace oil-gas mixed combustion control system are all controlled by the medium temperature transmitter 7.

[0019] The medium temperature signal is used as the main variable of the system. The gas flow regulating valve 10 or the fuel inlet regulating valve 3 and the fuel return regulating valve 4 are adjusted through the PLC controller 5 to distribute the fuel and air volume.

[0020] The system air volume control has two damper actuators, one is the combustion damper actuator 1, and the other is the atomization damper actuator 2. The system automatically adjusts the two damper actuators according to the load input.

[0021] In mixed combustion mode, if the gas volume cannot meet the load requirements, manually switch to oil supplement combustion mode.

[0022] The burner 8 comprises a combustion chamber 11, in which a first spiral heating tube 22 and a second spiral heating tube 23 are arranged in a spiral and cross-arranged manner. A conical bottom surface 21 is arranged at the bottom of the combustion chamber 11, and a bottom recovery nozzle 20 is arranged at the lowest point of the conical bottom surface 21 for recovering incompletely burned fuel oil. A rotating plate top bracket 16 and a rotating plate bottom bracket 18 are respectively fixed on the top of the inner wall of the combustion chamber 11 and the conical bottom surface 21, and a plurality of rotating plates 17 arranged in a circular array are rotatably installed between the rotating plate top bracket 16 and the rotating plate bottom bracket 18. Feeding pipes 19 are arranged at the rotation axis position of all rotating plates 17, and there are at least two feeding pipes 19, which are used to provide fuel oil and gas respectively. A top cone cover 12 is fixed at the top of the combustion chamber 11, and an exhaust channel 13 is fixedly arranged at the top of the top cone cover 12, and a gas turbine 14 is rotatably installed inside the exhaust channel 13, and the gas turbine 14 and all rotating plates 17 are fixedly transmission-matched through a transmission frame rod 15.

[0023] During the combustion process, a high temperature and high pressure environment will be generated inside the combustion chamber 11. At this time, the pressure inside the combustion chamber 11 increases, causing the high temperature and high pressure gas inside the combustion chamber 11 to be discharged through the exhaust passage 13. In this process, the gas will drive the gas turbine 14 to rotate. The rotation of the gas turbine 14 drives all the rotating plates 17 to rotate through the transmission frame rod 15. The rotation of the rotating plates 17 will drive the fuel and / or gas ejected from the feed pipe 19 to rotate (the feed pipe 19 is provided with multiple nozzles), so that it is subjected to centrifugal force, which allows more fuel and / or gas to gather to the edge of the inner wall of the combustion chamber 11. Since the first spiral heating tube 22 and the second spiral heating tube 23 are arranged on the edge of the inner wall of the combustion chamber 11, the first spiral heating tube 22 and the second spiral heating tube 23 can absorb more heat. The first spiral heating tube 22 and the second spiral heating tube 23 are arranged in a spiral cross manner, which can reduce the length of the same pipeline inside the combustion chamber 11, thereby ensuring the efficiency of the first spiral heating tube 22 and the second spiral heating tube 23 in absorbing heat (the liquid inside the first spiral heating tube 22 and the second spiral heating tube 23 has been completely heated, and if the pipeline is too long, excess heat will be wasted).

[0024] It consists of a combustion-supporting air door actuator 1, an atomizing air door actuator 2, a fuel inlet regulating valve 3, a fuel return regulating valve 4, a PLC controller 5, a fuel pressure transmitter 6, a medium temperature transmitter 7, a burner 8, a host computer 9, and a gas flow regulating valve 10.

[0025] The PLC controller 5 is respectively connected with the combustion-supporting damper actuator 1, the atomizing damper actuator 2, the fuel inlet regulating valve 3, the fuel return regulating valve 4, the medium temperature transmitter 7, the fuel pressure transmitter 6, the host computer 9, and the gas flow regulating valve 10. This structure can fully burn the fuel in the fuel, gas, and oil-gas mixed combustion modes, so that the exhaust gas meets the emission standards, and the medium temperature is controlled within the required range.

[0026] According to the combustion fuel used, it is divided into three modes: oil mode, gas mode and oil-gas mixed combustion mode.

[0027] First, when the fuel mode is selected through the upper computer 9 according to the working conditions, after the burner starts and runs to normal combustion, the control system tracks and adjusts the fuel return regulating valve 4 according to the fuel pressure transmitter 6, and the fuel furnace adjusts the fuel inlet regulating valve 3 and the damper actuator (combustion-supporting damper actuator 1, atomizing damper actuator 2) according to the medium temperature transmitter 7.

[0028] When the gas mode is selected, after the leak detection is passed, the main gas valve is opened, and after normal combustion, the control system can adjust the gas flow regulating valve 10 according to the medium temperature transmitter 7. When the gas volume cannot meet the load demand, it is manually switched to oil supplement and enters the mixed combustion mode.

[0029] In mixed combustion mode, first manually give the gas flow control valve 10 and the damper actuator (combustion-supporting damper actuator 1, atomizing damper actuator 2) an initial opening value, and the system will adjust the damper (combustion-supporting damper actuator 1, atomizing damper actuator 2) based on the initial opening according to the amount of oil replenishment. When the mixed combustion mode increases the load, adjust the gas first, then adjust the fuel oil; when reducing the load, adjust the fuel oil first, then adjust the gas. Each stage of adjustment is automatic proportional tracking adjustment.

[0030] It can realize the control of three operating modes: fuel oil, gas, and oil-gas mixed combustion, and automatic adjustment of combustion load; it can realize the control of the medium temperature of the thermal oil furnace; it can realize the stable adjustment of the oil supply pressure.

[0031] The mixed combustion control sequence is: mixed combustion operation mode → fan start (gas valve group leak detection) → front scavenging → ignition valve opening → establishment of ignition flame → main gas valve opening → establishment of main fire flame → normal combustion → automatic load (stage adjustment) → meeting shutdown conditions → closing fuel valve → closing main gas valve → rear scavenging → shutdown.

[0032] In addition, when the system is first started, the data acquisition program can be started to collect data related to the combustion process, including the flow of fuel and gas, the working status of the burner, the medium temperature, and the exhaust gas composition. These data are preliminarily processed and stored in the system database. The system will classify and analyze the historical data, and use the classification algorithm in machine learning (such as K-means clustering) to classify different combustion modes and working conditions. For new working conditions, the system will compare it with the existing patterns in the database to find the closest historical data and adapt the corresponding combustion mode. After the first selection of the appropriate combustion mode, the system will monitor the combustion state in real time, obtain real-time data through the medium temperature transmitter 7 and the fuel pressure transmitter 6, and make subtle adjustments to the fuel and gas ratio according to error feedback to keep the combustion in the optimal state. This process is similar to the integral link in PID control, which can effectively reduce the deviation.

[0033] When there is less associated gas, the system will select the fuel mode. The system calculates the optimal fuel input flow and dynamically adjusts the damper opening based on multiple parameters such as ambient temperature, fuel pressure, and preset target temperature, so that the fuel combustion process can achieve the goal of high efficiency and environmental protection. When the amount of associated gas is sufficient, the system switches to the gas mode. According to the composition analysis of the gas (obtained by the gas sensor) and the combustion load demand, the gas flow is automatically calculated and controlled. When the gas supply is insufficient or the load demand fluctuates greatly, the system switches to the mixed combustion mode. In this mode, the system will add fuel when the gas flow is insufficient, and automatically fine-tune the ratio of fuel and gas based on real-time combustion feedback.

[0034] Emission filtration and graded treatment: Primary filtration: The first step of the emission control module is to pass the exhaust gas through a mechanical filter to filter out large particles and impurities. These impurities may include incompletely burned fuel particles or other suspended matter. Primary filtration ensures that subsequent gas treatment processes are not interfered with by impurities; Ionization decomposition: After primary filtration, the exhaust gas is sent to the ionization chamber, and a high-voltage electric field is used to dissociate harmful molecules in the gas (such as nitrogen oxides, carbon monoxide, etc.) into relatively harmless atoms or molecules. This ionization decomposition technology can significantly reduce the concentration of harmful gases and is one of the key technologies to meet emission standards; Catalytic conversion: The dissociated gas enters the catalytic converter and is further converted into harmless substances such as carbon dioxide and water vapor with the help of catalysts (such as metals such as palladium and platinum).

Claims

1. An oilfield thermal oil furnace oil and gas mixed combustion control system, characterized in that: It comprises a combustion-supporting air damper actuator (1), an atomizing air damper actuator (2), a fuel inlet regulating valve (3), a fuel return regulating valve (4), a PLC controller (5), a fuel pressure transmitter (6), a medium temperature transmitter (7), a burner (8), a host computer (9) and a fuel gas flow regulating valve (10); The start / stop and load regulation of the oil-gas mixed combustion control system of the oil field thermal oil furnace are all controlled by the medium temperature transmitter (7).

2. The oil-gas mixed combustion control system of an oilfield thermal oil furnace according to claim 1, characterized in that: The medium temperature signal is used as the main variable of the system. The gas flow regulating valve (10) or the fuel inlet regulating valve (3) and the fuel return regulating valve (4) are adjusted through the PLC controller (5) to distribute the fuel and air volume.

3. The oil-gas mixed combustion control system of an oilfield thermal oil furnace according to claim 2 is characterized in that: The system air volume control has two damper actuators, one of which is the combustion damper actuator (1) and the other is the atomization damper actuator (2). The system automatically adjusts the two damper actuators according to the load input.

4. The oil-gas mixed combustion control system of an oilfield thermal oil furnace according to claim 3 is characterized in that: In mixed combustion mode, if the gas volume cannot meet the load requirements, manually switch to oil supplement combustion mode.

5. The oil-gas mixed combustion control system of an oilfield thermal oil furnace according to claim 4, characterized in that: The burner (8) comprises a combustion chamber (11), wherein a first spiral heating tube (22) and a second spiral heating tube (23) are arranged in a spiral and cross-arranged manner, and the bottom of the combustion chamber (11) is provided with a conical bottom surface (21), and a bottom recovery nozzle (20) is provided at the lowest point of the conical bottom surface (21) for recovering incompletely burned fuel.

6. The oil-gas mixed combustion control system of an oilfield thermal oil furnace according to claim 5, characterized in that: A rotating plate top bracket (16) and a rotating plate bottom bracket (18) are fixed to the top of the inner wall of the combustion chamber (11) and the conical bottom surface (21), respectively, and a plurality of rotating plates (17) arranged in a circular array are rotatably mounted between the rotating plate top bracket (16) and the rotating plate bottom bracket (18).

7. The oil-gas mixed combustion control system for a thermal oil furnace in an oil field according to claim 6, characterized in that: Feeding pipes (19) are arranged at the positions of the rotation axes of all the rotating dial plates (17), and there are at least two feeding pipes (19), which are used to supply fuel oil and fuel gas respectively.

8. The oil-gas mixed combustion control system for a thermal oil furnace in an oil field according to claim 7, characterized in that: A top cone cover (12) is fixed on the top of the combustion chamber (11), an exhaust passage (13) is fixedly provided on the top of the top cone cover (12), a gas turbine (14) is rotatably mounted inside the exhaust passage (13), and the gas turbine (14) and all the rotating dial plates (17) are fixedly coupled via a transmission frame rod (15).

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