Supercritical gas boiler stable operation control method and system

Abstract

The present invention relates to a method and system for controlling the stable operation of a supercritical gas boiler. The method comprises: setting a monitoring position and an adjusting position on a gas main pipeline, monitoring the gas pressure through each pressure monitoring unit at the monitoring position, and calculating the change ΔQ of the gas heat supply caused by the gas fluctuation. 煤气 ; The time required for gas to run from the monitoring position to the regulating position is t1; if ΔQ 煤气 >0, after time t1, reduce the main flow control valve opening, if ΔQ 煤气 <0, after time t1, the main flow regulating valve opening is increased to improve the stability of the main steam parameters of the gas boiler. The present invention sets a monitoring position upstream of the boiler burner. When gas fluctuations occur during boiler operation, the opening of the flow regulating valve can be adjusted in advance according to the monitored gas fluctuations, thereby maintaining the stability of the heat released by gas combustion per unit time, thereby improving the stability of the main steam parameters of the gas boiler.

Description

Technical Field

[0001] The invention relates to a supercritical gas boiler stable operation control method and a supercritical gas boiler stable operation control system. Background Art

[0002] The low calorific value coal gas power generation industry in steel plants has gone through five generations of technology changes: medium temperature and medium pressure, high temperature and high pressure, high temperature and ultra-high pressure, subcritical, and supercritical. Among them, before the subcritical technology, gas boilers were all drum boilers; and for supercritical technology, boilers use direct current furnaces.

[0003] The amount of coal gas in steel mills is always in an unstable and fluctuating state. In the operation of gas boilers, the matching and adjustment of fuel and feed water is very important, which directly affects the safe operation of the boiler. At present, in subcritical and subcritical gas generator sets, the control of boiler fuel and feed water can be indirectly controlled by the intermediate drum water level, but supercritical direct current furnaces have no drums, and there is no reliable and mature technology for matching fuel and feed water under coal gas fluctuations. Summary of the invention

[0004] The present invention relates to a supercritical gas boiler stable operation control method and a supercritical gas boiler stable operation control system, which can at least solve some defects of the prior art.

[0005] The present invention relates to a method for controlling the stable operation of a supercritical gas boiler, the method comprising:

[0006] A monitoring position and a regulating position are arranged on the main gas pipeline of the boiler, a plurality of pressure monitoring units are arranged in sequence at the monitoring position along the gas flow direction, and the regulating position is located downstream of the monitoring position and is provided with a main flow regulating valve;

[0007] The gas pressure is monitored by each pressure monitoring unit at the monitoring position, and the change in gas heat supply caused by the gas fluctuation is calculated based on the monitored gas pressure fluctuation. 煤气 ; Calculate the time t1 required for gas to run from the monitoring position to the regulating position;

[0008] If ΔQ 煤气 >0, after time t1, the main flow regulating valve opening is reduced to improve the stability of the main steam parameters of the gas boiler;

[0009] If ΔQ 煤气 <0, after time t1, the main flow regulating valve opening is increased to improve the stability of the main steam parameters of the gas boiler;

[0010] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve unchanged.

[0011] As one of the implementation modes, when adjusting the opening of the main flow regulating valve, the adjustment goal is to control the fluctuation range of the boiler midpoint temperature within 0-10°C.

[0012] As one of the implementation modes, the method further includes:

[0013] When the main flow regulating valve is adjusted to the maximum opening and still cannot reach the control target, the main feed water flow of the boiler is further adjusted to reach the control target.

[0014] As one of the implementation methods, the adjustment amount of the boiler main feed water flow rate is calculated according to the following formula:

[0015]

[0016] Where η is the thermal efficiency of the boiler, h out is the specific enthalpy of feed water after heat exchange, h in is the specific enthalpy of feed water before heat exchange.

[0017] As one of the implementation modes, the method further includes:

[0018] Obtain the time t2 required for gas to be transmitted from the monitoring position to the boiler burner and the time t3 required for feed water to be transmitted from the feed water pump to the boiler water wall.

[0019] If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3; or external gas is added to the main gas pipeline to improve the stability of the main steam parameters of the gas boiler;

[0020] If t2<t3, before the main feed water flow of the boiler is adjusted to the right position, the opening of the branch flow regulating valve on the gas branch pipe at the inlet side of the boiler burner is reduced to improve the stability of the main steam parameters of the gas boiler.

[0021] The present invention also relates to a supercritical gas boiler stable operation control system, comprising a gas main pipeline and a plurality of gas branch pipelines connected to the boiler burners one by one, a monitoring position and an adjustment position are arranged on the gas main pipeline, a gas calorific value meter and a plurality of pressure monitoring units sequentially distributed along the gas flow direction are arranged at the monitoring position, the adjustment position is located downstream of the monitoring position and is provided with a main flow regulating valve;

[0022] It also includes a main controller and a comparator, wherein the main controller is used to:

[0023] Acquiring monitoring data of the gas calorific value meter and monitoring data of each of the pressure monitoring units;

[0024] and sending the monitoring data of each pressure monitoring unit to a comparator for comparison, and obtaining the comparison result of the comparator;

[0025] And the change ΔQ of the gas heat supply caused by the gas fluctuation is calculated according to the comparison result. 煤气 , and controls the opening of the main flow control valve according to a predetermined strategy.

[0026] As one of the implementation modes, the predetermined strategy includes:

[0027] If ΔQ 煤气 >0, after time t1, the main flow regulating valve opening is reduced to improve the stability of the main steam parameters of the gas boiler;

[0028] If ΔQ 煤气 <0, after time t1, the main flow regulating valve opening is increased to improve the stability of the main steam parameters of the gas boiler;

[0029] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve unchanged.

[0030] As one of the implementation modes, the gas main pipeline is connected to a gas storage bypass, the gas storage bypass is connected to an external gas source, and the gas storage bypass is provided with a bypass regulating valve and a shut-off valve.

[0031] The present invention has at least the following beneficial effects:

[0032] The present invention sets a monitoring point upstream of the boiler burner. When gas fluctuations occur during the operation of the boiler, the opening of the flow control valve can be adjusted in advance according to the fluctuations in the heat supply value corresponding to the gas fluctuations monitored at the monitoring point, thereby maintaining the stability of the heat released by gas combustion per unit time, thereby improving the stability of the main steam parameters of the gas boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of a gas pipeline of a supercritical gas boiler provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Embodiment 1

[0037] An embodiment of the present invention provides a method for controlling the stable operation of a supercritical gas boiler, the method comprising:

[0038] A monitoring position 11 and a regulating position are set on the main gas pipeline 1 of the boiler. A plurality of pressure monitoring units 111 are sequentially arranged at the monitoring position 11 along the gas flow direction. The regulating position is located downstream of the monitoring position 11 and is provided with a main flow regulating valve 12.

[0039] The gas pressure is monitored by each pressure monitoring unit 111 at the monitoring position 11, and the change ΔQ of the gas heat supply caused by the gas fluctuation is calculated based on the monitored gas pressure fluctuation. 煤气 ; Calculate the time t1 required for the gas to run from the monitoring position 11 to the regulating position;

[0040] If ΔQ 煤气 >0, after time t1, the opening of the main flow regulating valve 12 is reduced to improve the stability of the main steam parameters of the gas boiler;

[0041] If ΔQ 煤气 <0, after time t1, the opening of the main flow regulating valve 12 is increased to improve the stability of the main steam parameters of the gas boiler;

[0042] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve 12 unchanged.

[0043] The monitoring position 11 is a section, that is, has a certain pipeline axial length, such as a monitoring section of the gas main pipeline 1, which is convenient for the arrangement of monitoring equipment.

[0044] The number of gas pressure measuring points (i.e., pressure monitoring units 111) is preferably 3 or more to ensure the accuracy and reliability of pressure monitoring. The distance between two adjacent gas pressure measuring points is preferably within the range of 1 to 20 m, and more preferably within the range of 5 to 15 m.

[0045] In one embodiment, the gas heat supply is calculated using the following formula:

[0046] Q 煤气 =qm 气

[0047] Wherein, q is the calorific value of the gas, which can be monitored in real time by installing a gas calorific value meter 112 on the pipeline; m 气 is the gas flow rate, m 气 It can be obtained by monitoring the gas pressure.

[0048] Correspondingly, a gas calorific value meter 112 is also provided at the monitoring position 11, which can monitor the calorific value of the gas online. The gas calorific value meter 112 can be arranged on the same cross-section of the gas main pipeline 1 relative to one of the pressure monitoring units 111, or can be arranged between two adjacent pressure monitoring units 111, or can be arranged downstream of each pressure monitoring unit 111.

[0049] In actual operation, the fluctuation of the calorific value of coal gas is relatively small. Therefore, in this embodiment, the impact of the fluctuation of coal gas flow on the operation of the boiler is mainly considered.

[0050] There is a certain distance between the monitoring position 11 and the regulating position to ensure that corresponding processing can be carried out in advance when the gas fluctuates. In one embodiment, the distance between the monitoring position 11 and the regulating position is more than 20m, for example, controlled within the range of 20 to 100m.

[0051] There is a certain distance between the adjustment position and the boiler burner 5, and the distance is preferably greater than 20m, for example, in the range of 20 to 100mm.

[0052] Furthermore, when calculating the time t1 required for the gas to run from the monitoring position 11 to the regulating position, the location of the gas pressure measuring point at the center position or the center position of the monitoring position 11 is used as the starting operation position of the gas, and the gas flow rate can be calculated based on the gas pressure monitored at the starting operation position and combined with the pipe diameter, etc.

[0053] Furthermore, when calculating ΔQ 煤气 When calculating the pressure difference between two adjacent gas pressure measuring points, the gas pressure fluctuation amount is first obtained. Specifically, the pressure difference between each adjacent gas pressure measuring point is calculated, and the average value of each pressure difference is taken as the gas pressure fluctuation amount. When calculating the pressure difference between each adjacent gas pressure measuring point, it is preferred that the monitoring data of the downstream gas pressure measuring point is subtracted from the monitoring data of the upstream gas pressure measuring point. Since gas fluctuation is generally a creeping process rather than a sudden change process, the above calculation method can ensure the accuracy and reliability of the monitoring results.

[0054] The main flow regulating valve 12 is an automatic valve, and a flow regulating valve such as an electric butterfly valve can be used.

[0055] Further preferably, when adjusting the opening of the main flow regulating valve 12, the adjustment goal is to control the fluctuation range of the boiler midpoint temperature within 0-10°C, which can achieve the above-mentioned effect of improving the stability of the main steam parameters of the gas boiler.

[0056] In the case where the calorific value of the coal gas does not fluctuate much, preferably, for every 1 KPa drop or rise in the coal gas pressure, the opening of the main flow regulating valve 12 increases or decreases by 1% to 10% accordingly.

[0057] Further preferably, the above control method further includes:

[0058] When the main flow regulating valve 12 is adjusted to the maximum opening and still cannot reach the control target, the main feed water flow of the boiler is further adjusted to reach the control target. Among them, the main feed water flow of the boiler is further adjusted after the flow regulating valve is opened to the maximum opening.

[0059] When the boiler is running, in order to ensure the stability of the main steam parameters, the fuel and feed water should meet the following relationship:

[0060] Q 水 =ηQ 煤气

[0061] Among them, Q 水 is the heat absorbed by the feed water heat exchange; η is the boiler thermal efficiency.

[0062] Q 水 =m 水 (h out -h in )

[0063] Among them, m 水 is the main feed water flow rate of the boiler; h out is the specific enthalpy of feed water after heat exchange, h in is the specific enthalpy of feed water before heat exchange. out and h in The table operation is generally referred to in the current engineering "Handbook of Thermodynamic Properties of Water and Steam"; the parameters of the boiler main feed water and main steam are applicable to the "Water and Superheated Steam Table" in the manual. Specifically, according to the temperature and pressure parameters of the boiler main feed water, the "Water and Superheated Steam Table" can be queried to obtain the specific enthalpy value h of the boiler main feed water. in According to the temperature and pressure parameters of the boiler main steam, query the "water and superheated steam table" to obtain the specific enthalpy value h of the boiler main steam out .

[0064] Therefore, the calculation formula for the boiler main feed water flow is:

[0065]

[0066] Although the boiler thermal efficiency η is different under different loads, since the fluctuation of coal gas is generally a continuous process, the boiler thermal efficiency η will not change suddenly, so it can be approximately considered that the boiler thermal efficiency η at two adjacent monitoring moments remains unchanged. However, preferably, after each adjustment of the opening of the main flow control valve 12, the boiler thermal efficiency η is recalculated, and the specific calculation method is a conventional technology in the field and is not described here.

[0067] Accordingly, the adjustment amount of the boiler main feed water flow is calculated according to the following formula:

[0068]

[0069] Where η is the thermal efficiency of the boiler, h out is the specific enthalpy of feed water after heat exchange, h in is the specific enthalpy of feed water before heat exchange.

[0070] According to the above calculation results, the frequency converter of the feed water pump can be adjusted to achieve the purpose of adjusting the main feed water flow of the boiler. The adjustment amount of the main feed water flow of the boiler is equal to Δm 水 This is obviously an ideal regulation target, but considering the actual operating conditions, the regulation amount of the boiler main feed water flow is close to this Δm 水 It is considered reasonable, and the specific difference should meet the requirement of ensuring that the fluctuation range of the boiler mid-point temperature is between 0 and 10°C.

[0071] Furthermore, the method further comprises:

[0072] Obtain the time t2 required for gas to be transmitted from the monitoring position 11 to the boiler burner 5 and the time t3 required for feed water to be transmitted from the feed water pump to the boiler water wall,

[0073] If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3. Alternatively, external gas is added to the main gas pipeline 1 to improve the stability of the main steam parameters of the gas boiler, wherein the external gas addition point is located downstream of the monitoring position 11, and can be located upstream or downstream of the adjustment position. The time when the external gas reaches the boiler burner 5 is preferably the same as t3. When the gas fluctuation signal is monitored, the external gas is added, and the ventilation time of the external gas is t2-t3. A gas storage bypass 2 can be connected to the main gas pipeline 1, and the gas storage bypass 2 is connected to an external gas source 21, and a bypass regulating valve 22 and a quick-cut valve are set on the gas storage bypass 2, and the flow rate of the external gas is controlled by the bypass regulating valve 22.

[0074] If t2<t3, before the boiler main feed water flow is adjusted to the right position, the opening of the branch pipe flow regulating valve 41 on the gas branch pipe 4 at the inlet side of the boiler burner 5 is reduced to improve the stability of the main steam parameters of the gas boiler. Furthermore, when time t3 is reached, the opening of the branch pipe flow regulating valve 41 is reset to the position before the gas fluctuation to further improve the stability of the subsequent boiler operation.

[0075] Based on the above scheme, the time for gas fluctuations to reach the boiler burner 5 and the time for feed water to reach the boiler water-cooled wall are fully considered to ensure the reliability of the adjustment operation, which can further improve the operating stability of the gas boiler and ensure that the main steam parameters under various operating conditions can be controlled within the target range.

[0076] The gas transported by the main gas pipeline 1 is preferably steel plant gas, such as blast furnace gas, etc. The main steam parameters are preferably a pressure not less than 22.12Mpa and a temperature not less than 540°C. The supercritical gas boiler can be applied to supercritical gas generator sets, ultra-supercritical gas generator sets, etc.

[0077] Embodiment 2

[0078] An embodiment of the present invention provides a supercritical gas boiler stable operation control system, including a gas main pipeline 1 and a plurality of gas branch pipelines 4 connected to each boiler burner 5 in a one-to-one correspondence. A monitoring position 11 and an adjustment position are provided on the gas main pipeline 1. A gas calorific value meter 112 and a plurality of pressure monitoring units 111 distributed in sequence along the gas flow direction are provided at the monitoring position 11. The adjustment position is located downstream of the monitoring position 11 and is provided with a main flow regulating valve 12.

[0079] The pressure monitoring unit 111 may be a pressure measuring device such as a pressure transmitter.

[0080] There is a certain distance between the monitoring position 11 and the regulating position to ensure that corresponding processing can be carried out in advance when the gas fluctuates. In one embodiment, the distance between the monitoring position 11 and the regulating position is more than 20m, for example, controlled within the range of 20 to 100m.

[0081] There is a certain distance between the adjustment position and the boiler burner 5, and the distance is preferably greater than 20 m, for example, in the range of 20 to 100 m.

[0082] The monitoring position 11 is a section, that is, has a certain pipeline axial length, such as a monitoring section of the gas main pipeline 1, which is convenient for the arrangement of monitoring equipment.

[0083] The number of gas pressure measuring points (i.e., pressure monitoring units 111) is preferably 3 or more to ensure the accuracy and reliability of pressure monitoring. The distance between two adjacent gas pressure measuring points is preferably within the range of 1 to 20 m, and more preferably within the range of 5 to 15 m.

[0084] The gas calorific value meter 112 may be arranged on the same cross section of the gas main pipeline 1 opposite to one of the pressure monitoring units 111 , or may be arranged between two adjacent pressure monitoring units 111 , or may be arranged downstream of each pressure monitoring unit 111 .

[0085] The main flow regulating valve 12 is an automatic valve, and a flow regulating valve such as an electric butterfly valve can be used.

[0086] Furthermore, the system further comprises a main controller and a comparator, wherein the main controller is used for:

[0087] Acquire the monitoring data of the gas calorific value meter 112 and the monitoring data of each of the pressure monitoring units 111;

[0088] and sending the monitoring data of each pressure monitoring unit 111 to a comparator for comparison, and obtaining a comparison result of the comparator;

[0089] And the change ΔQ of the gas heat supply caused by the gas fluctuation is calculated according to the comparison result. 煤气 , and controls the opening of the main flow control valve 12 according to a predetermined strategy.

[0090] Further, the predetermined strategy may refer to the relevant content in the above-mentioned embodiment 1, for example, the predetermined strategy includes:

[0091] If ΔQ 煤气 >0, after time t1, the opening of the main flow regulating valve 12 is reduced to improve the stability of the main steam parameters of the gas boiler;

[0092] If ΔQ 煤气 <0, after time t1, the opening of the main flow regulating valve 12 is increased to improve the stability of the main steam parameters of the gas boiler;

[0093] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve 12 unchanged.

[0094] Furthermore, the main controller is also used to adjust the frequency of the inverter of the main water supply pump so that the amount of gas supplied matches the main water supply flow rate. For related content, please refer to the above embodiment 1, which will not be repeated here.

[0095] Furthermore, if Figure 1The gas branch pipeline 4 is provided with a branch flow regulating valve 41, and a pressure monitoring device 42 can be further provided on the gas branch pipeline 4. The branch flow regulating valve 41 and the pressure monitoring device 42 are both electrically connected to the main controller. In addition, a shut-off valve 43 is also provided on the gas branch pipeline 4, such as a hydraulic shut-off valve, which can further improve the reliability of system operation.

[0096] Furthermore, if Figure 1 The gas main pipeline 1 is connected to a gas storage bypass 2, and the gas storage bypass 2 is connected to an external gas source 21. The gas storage bypass 2 is provided with a bypass regulating valve 22 and a cut-off valve 23. The external gas source 21 can be an external gas storage tank, etc. The external gas can be the same type of gas as the gas supplied by the gas main pipeline 1, for example, both are blast furnace gas, and the external gas storage tank can be filled in advance at the initial stage of operation. The bypass point of the gas storage bypass 2 is preferably located downstream of the monitoring position 11, and can be located upstream or downstream of the regulating position.

[0097] The above main controller is also used to:

[0098] Obtain the time t2 required for gas to be transmitted from the monitoring position 11 to the boiler burner 5 and the time t3 required for feed water to be transmitted from the feed water pump to the boiler water wall; send t2 and t3 to the comparator for comparison and obtain the comparison result of the comparator; and execute the setting strategy according to the comparison result. The above setting strategy can refer to the relevant content in Example 1.

[0099] In addition, if Figure 1 Preferably, a heat exchanger 3 is also provided at the tail end of the main gas pipeline 1. The heat exchanger 3 is preferably a flue gas-gas indirect heat exchanger, which can utilize the waste heat of the flue gas discharged by the boiler to improve the combustion effect of the gas.

[0100] Alternatively, if Figure 1 An electric blind plate valve 13 and a hydraulic quick-cut valve 14 are also provided on the gas main pipeline 1, which can further improve the reliability of system operation.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the stable operation of a supercritical gas boiler, characterized in that: The method comprises: A monitoring position and a regulating position are arranged on the main gas pipeline of the boiler, a plurality of pressure monitoring units are arranged in sequence at the monitoring position along the gas flow direction, and the regulating position is located downstream of the monitoring position and is provided with a main flow regulating valve; The gas pressure is monitored by each pressure monitoring unit at the monitoring position, and the change in gas heat supply caused by the gas fluctuation is calculated based on the monitored gas pressure fluctuation. 煤气 ; Calculate the time t1 required for gas to run from the monitoring position to the regulating position; If ΔQ 煤气 >0, after time t1, the main flow regulating valve opening is reduced to improve the stability of the main steam parameters of the gas boiler; If ΔQ 煤气 <0, after time t1, the main flow regulating valve opening is increased to improve the stability of the main steam parameters of the gas boiler; If ΔQ 煤气 =0, keep the main flow regulating valve opening unchanged; When the main flow regulating valve is adjusted to the maximum opening and still cannot reach the control target, further adjusting the boiler main feed water flow to reach the control target; specifically, the method further includes: Obtain the time t2 required for gas to be transmitted from the monitoring position to the boiler burner and the time t3 required for feed water to be transmitted from the feed water pump to the boiler water wall. If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3; or external gas is added to the main gas pipeline to improve the stability of the main steam parameters of the gas boiler; If t2<t3, before the main feed water flow of the boiler is adjusted to the right position, the opening of the branch flow regulating valve on the gas branch pipe at the inlet side of the boiler burner is reduced to improve the stability of the main steam parameters of the gas boiler.

2. The method for controlling the stable operation of a supercritical gas boiler according to claim 1, characterized in that: When adjusting the opening of the main flow regulating valve, the goal of the adjustment is to control the fluctuation range of the boiler midpoint temperature within 0-10°C.

3. The method for controlling the stable operation of a supercritical gas boiler according to claim 1, characterized in that: The adjustment amount of the boiler main feed water flow is calculated according to the following formula: ； Where η is the thermal efficiency of the boiler, h out is the specific enthalpy of feed water after heat exchange, h in is the specific enthalpy of feed water before heat exchange.

4. A supercritical gas boiler stable operation control system, comprising a gas main pipeline and a plurality of gas branch pipelines connected one by one to each boiler burner, characterized in that: A monitoring position and a regulating position are provided on the gas main pipeline. A gas calorific value meter and a plurality of pressure monitoring units sequentially distributed along the gas flow direction are provided at the monitoring position. The regulating position is located downstream of the monitoring position and is provided with a main flow regulating valve. It also includes a main controller and a comparator, wherein the main controller is used to: Acquiring monitoring data of the gas calorific value meter and monitoring data of each of the pressure monitoring units; and sending the monitoring data of each pressure monitoring unit to a comparator for comparison, and obtaining the comparison result of the comparator; And the change ΔQ of the gas heat supply caused by the gas fluctuation is calculated according to the comparison result. 煤气 , and control the opening of the main flow control valve according to a predetermined strategy; The predetermined strategy includes: If ΔQ 煤气 >0, after time t1, the main flow regulating valve opening is reduced to improve the stability of the main steam parameters of the gas boiler; If ΔQ 煤气 <0, after time t1, the main flow regulating valve opening is increased to improve the stability of the main steam parameters of the gas boiler; If ΔQ 煤气 =0, keep the main flow regulating valve opening unchanged; When the main flow regulating valve is adjusted to the maximum opening and still cannot reach the control target, the main feed water flow of the boiler is further adjusted to reach the control target; specifically including: Obtain the time t2 required for gas to be transmitted from the monitoring position to the boiler burner and the time t3 required for feed water to be transmitted from the feed water pump to the boiler water wall. If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3; or external gas is added to the main gas pipeline to improve the stability of the main steam parameters of the gas boiler; If t2<t3, before the main feed water flow of the boiler is adjusted to the right position, the opening of the branch flow regulating valve on the gas branch pipe at the inlet side of the boiler burner is reduced to improve the stability of the main steam parameters of the gas boiler.

5. The supercritical gas boiler stable operation control system according to claim 4, characterized in that: The gas main pipeline is connected with a gas storage bypass, the gas storage bypass is connected with an external gas source, and the gas storage bypass is provided with a bypass regulating valve and a cut-off valve.

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