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Summary of Precision Control of Wet Steam Generator Combustion Systems: With the thermal exploration and trial production of ultra-heavy oil reservoirs, low-permeability oil reservoirs and deep well heavy oil in oil fields, the technological requirements for high-pressure wet steam generators are getting higher and higher. In order to ensure the safe operation of wet steam generators, it is necessary to improve the control accuracy of the combustion system. This article discusses a comprehensive improvement plan for the combustion control system of the high-pressure wet steam generator of special thermal recovery equipment in oil fields, and explores and attempts to improve the equipment technology of modern enterprises. At present, high-pressure wet steam generators (generators for short) used in oil fields commonly have control lag and failure problems in combustion control, which are mainly manifested in delayed tracking of water and fire quantities, and failure or distortion of connecting rod transmission. These problems are very dangerous for the operation of subcritical and supercritical high-pressure wet steam generators. Only by improving the control accuracy of the generator combustion system can the safe operation of the equipment be ensured. Therefore, the original combustion control system has been improved. The operation of the generator combustion system is a systematic project. Only by coordinating the supply of oil, water, steam and gas can the improvement of the combustion system be realized. This improvement is a comprehensive improvement of pressure, flow, air volume, oil supply volume, dryness and combustion efficiency to achieve precise control of the combustion system. 1. Pressure control Currently, the pressure control of the generator is accomplished by a pneumatic pressure controller. When the steam pressure rises, the pressure controller outputs a pressure signal to the high-value selector. The high-value selector compares it with the given air pressure signal and adjusts the opening of the return valve. During the entire adjustment process, due to the gas signal transmission, not only the signal was weak and the speed was very slow, but the pressure controller, high value selector and return valve often failed, causing the entire adjustment to lag and malfunction. To solve this problem, the original pressure adjustment system was changed to a water supply plunger pump frequency control. The water supply plunger pump frequency converter is a relatively mature control device. The generator steam outlet pressure is converted by the sensor into an electrical signal and then transmitted to the water supply plunger pump frequency converter to control the motor speed. When the steam pressure increases to the set value, the motor speed immediately decreases and the water supply to the generator decreases, thus reducing the steam outlet pressure. This control has the characteristics of fast adjustment and high reliability. 2. Flow control At present, the flow of the generator mainly depends on the differential pressure transmitter and manual control. Because there are many control links, the safety and reliability are poor. In order to solve the problem of inaccurate and untimely flow control of the generator, the frequency converter control of the water supply pump can be used. Under special steam injection conditions, the frequency converter parameters are manually set to keep the water supply volume of the generator at a constant ； After normal operation, the flow rate can be automatically adjusted according to well conditions and steam injection pressure. This adjustment is relatively stable and reliable. 3. Air volume control Currently, the air volume of the generator is controlled by the valve positioner. When the water volume changes, the valve positioner gives an air pressure signal to the air motor, and the air motor controls the opening of the burner damper through the linkage mechanism. It is very difficult to achieve precise control of this kind. In order to achieve good tracking of wind, fire and water volume, the fire volume signal can be directly transmitted to the blower frequency converter. When the opening of the air door remains unchanged, the blower motor speed is adjusted to meet the generator's air volume requirements. When the generator is ignited, the parameters are manually set to ensure the air blast volume. ； When the generator is running normally, it switches to fire volume control. This kind of control has fewer links, fast conversion and reliable performance. 4. Dryness control At present, automatic control of the steam dryness of the generator cannot be achieved. To achieve automatic control, it is necessary to be equipped with an online dryness testing instrument and a signal converter to convert the dryness signal into an electrical signal and send it to the fuel oil pump motor frequency converter to automatically adjust the speed of the fuel oil motor. 5. Furnace tube temperature control At present, when the furnace tube temperature reaches the set value, the generator will shut down due to high tube temperature. Even if the tube temperature rises instantaneously, the furnace will shut down, affecting the steam injection construction. If the temperature of the furnace tube is instantly higher than the set value, the control system can adjust itself and lower the tube temperature by reducing the amount of fire and increasing the amount of water, thus avoiding furnace shutdown. To achieve this control, the temperature sensor signal needs to be transmitted to the fuel oil pump inverter and the water supply pump inverter. 6. Detection and adjustment of combustion efficiency At present, the combustion efficiency of the generator cannot be automatically detected and controlled. To achieve this, it is necessary to equip an online flue gas analyzer and a signal converter to convert the flue gas signal into an electrical signal and send it to the blower motor inverter to ensure sufficient combustion. The above six types of control are all interdependent and restricted, and are in an interactive balance. The signal selection should have priority and importance, which was a key consideration in the design. 7. Application of computer measurement and control system This system can complete the following functions. 1． Automatically collect and process various on-site data. 2. The system software is under the operating system platform and uses industrial control configuration software as the platform. The human-machine interface is graphical and Chinese-language, making it easy and convenient to operate. The operation interface includes: (1) Display the entire process of the boiler process, and each screen dynamically displays the process parameters and process flow ； (2) Display system parameters in chart format ； (3) Real-time dynamic display of relevant alarm parameters ； (4) Historical curve trend chart record of important system parameters ； (5) Real-time curve trend chart recording of important system parameters ； (6) Modify the alarm limit value online according to the operation level. 3． Realize export steam pressure, air supply volume and boiler water supply control. 4. Realize automatic alarm and protection functions. 5. The system prints various production reports according to requirements. Through modification, the high-pressure wet steam generator operates more smoothly and safely.