Gas supply system and stable operation control method for supercritical gas boiler

Abstract

The present invention relates to a gas supply system for a supercritical gas boiler, comprising a gas main pipeline and a plurality of gas branch pipelines connected to each boiler burner in a one-to-one correspondence. A gas storage device and a main flow regulating valve are provided on the gas main pipeline, and the main flow regulating valve is located downstream of the gas storage device. In addition, a method for controlling the stable operation of a supercritical gas boiler is provided, which is implemented based on the above-mentioned gas supply system. The present invention arranges a gas storage device on the gas main pipeline, and the gas storage device can be used as a primary buffer, which can significantly alleviate the adverse impact of gas fluctuations on the boiler and improve the operating stability of the supercritical gas boiler and the generator set; the gas storage device cooperates with the main flow regulating valve to realize secondary regulation of gas fluctuations, and the operating stability of the supercritical gas boiler and the generator set is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of coal gas power generation, and in particular relates to a coal gas supply system of a supercritical coal gas boiler and a method for controlling the stable operation of the supercritical coal gas boiler. 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 gas supply system for a supercritical gas boiler and a method for controlling the stable operation of a supercritical gas boiler, which can at least solve some of the defects of the prior art.

[0005] The present invention relates to a gas supply system for a supercritical gas boiler, comprising a gas main pipeline and a plurality of gas branch pipelines connected one-to-one with each boiler burner, wherein a gas storage device and a main flow regulating valve are arranged on the gas main pipeline, and the main flow regulating valve is located downstream of the gas storage device.

[0006] As one of the implementation modes, a first monitoring position is provided on the gas main pipeline, and the first monitoring position is located between the gas storage device and the main flow regulating valve. A gas calorific value monitoring unit and a plurality of first pressure monitoring units arranged in sequence along the gas flow direction are provided at the first monitoring position.

[0007] As one of the implementation modes, a second monitoring position is further provided on the gas main pipeline, and the second monitoring position is located upstream of the gas storage device. At the monitoring position, a plurality of second pressure monitoring units are sequentially provided along the gas flow direction.

[0008] As one of the implementation modes, a branch pipe flow regulating valve is also provided on the gas branch pipeline.

[0009] As one of the implementation modes, a bypass pipe is further provided on the gas main pipeline, two ends of the bypass pipe are respectively connected to the upstream and downstream of the gas storage device, and a bypass valve is provided on the bypass pipe.

[0010] The present invention also relates to a method for controlling the stable operation of a supercritical gas boiler, the method being implemented based on the gas supply system of the supercritical gas boiler mentioned above;

[0011] The method comprises:

[0012] When the upstream gas pressure fluctuation is within the set fluctuation range, the upstream gas first enters the gas storage device for buffering, and the gas storage device supplies gas to the boiler burner to achieve a primary buffer for gas fluctuations;

[0013] When the upstream gas pressure fluctuation exceeds the set fluctuation range and / or the gas calorific value at the outlet side of the gas storage device fluctuates, the gas flow is adjusted through the main flow regulating valve on the basis of the primary buffer of the gas storage device to achieve secondary regulation of the gas fluctuation.

[0014] As one of the implementation modes, regulating the gas flow rate by the main flow regulating valve specifically includes:

[0015] A first monitoring position is arranged on the gas main pipeline, the first monitoring position is located between the gas storage device and the main flow regulating valve, and a gas calorific value monitoring unit and a plurality of first pressure monitoring units arranged in sequence along the gas flow direction are arranged at the first monitoring position;

[0016] The gas pressure is monitored by each first pressure monitoring unit at the first monitoring position, 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 first monitoring position to the main flow regulating valve;

[0017] 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;

[0018] 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;

[0019] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve unchanged.

[0020] As one of the implementation modes, the method further includes:

[0021] 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.

[0022] As one of the implementation modes, the method further includes:

[0023] Obtain the time t2 required for gas to be transmitted from the first 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,

[0024] If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3;

[0025] 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.

[0026] As one of the implementation modes, the method further includes:

[0027] A bypass pipe is arranged on the gas main pipeline, the two ends of the bypass pipe are respectively connected to the upstream and downstream of the gas storage device, and a bypass valve is arranged on the bypass pipe;

[0028] Monitoring gas pressure fluctuations upstream of the gas storage device, when the upstream gas pressure does not fluctuate or the upstream gas pressure fluctuation is within the allowable fluctuation range, the upstream gas directly flows through the bypass pipe; when the gas pressure fluctuation exceeds the allowable fluctuation range, the upstream gas enters the gas storage device;

[0029] And / or, a bypass flow regulating valve is arranged on the bypass pipe, and a stable flow rate is set through the bypass pipe. When the upstream gas pressure fluctuates positively, the bypass pipe maintains a normal gas flow rate, and the excess gas enters the gas storage device; when the upstream gas pressure fluctuates negatively, all the gas flows through the bypass pipe, and the fluctuation amount is supplemented by the gas storage device.

[0030] The present invention has at least the following beneficial effects:

[0031] In the present invention, a gas storage device is arranged on the gas main pipeline. The gas storage device can serve as a primary buffer, which can significantly alleviate the adverse impact of gas fluctuations on the boiler and improve the operating stability of the supercritical gas boiler and the generator set; the gas storage device cooperates with the main flow regulating valve to achieve secondary regulation of gas fluctuations, and the operating stability of the supercritical gas boiler and the generator set is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic structural diagram of a gas supply system for a supercritical gas boiler provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] 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.

[0035] Embodiment 1

[0036] like Figure 1 An embodiment of the present invention provides a gas supply system for a supercritical gas boiler, 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 gas storage device 2 and a main flow regulating valve 13 are provided on the gas main pipeline 1, and the main flow regulating valve 13 is located downstream of the gas storage device 2.

[0037] The gas storage device 2 is located downstream of the main gas source connected to the gas main pipeline 1. In one embodiment, the gas storage device 2 is a gas cabinet, which is a mature gas storage equipment, and the specific structure is not described here.

[0038] In this embodiment, a gas storage device 2 is arranged on the gas main pipeline 1. The gas storage device 2 can serve as a primary buffer, which can significantly alleviate the adverse impact of gas fluctuations on the boiler and improve the operating stability of the supercritical gas boiler and the generator set; the gas storage device 2 cooperates with the main flow regulating valve 13 to achieve secondary regulation of gas fluctuations, and the operating stability of the supercritical gas boiler and the generator set is higher.

[0039] Optionally, multiple sets of gas storage devices 2 can be provided, and each gas storage device 2 is connected in parallel, so that each gas storage device 2 can receive upstream gas and supply gas to downstream, which can further improve the operating stability and reliability of the supercritical gas boiler and the generator set. For example, two sets of gas storage devices 2 are provided, and when one set of gas storage devices 2 supplies gas to the downstream, the other set of gas storage devices 2 receives upstream gas; based on this scheme, on the one hand, it can avoid unnecessary fluctuations caused by the gas storage device 2 taking in and exhausting gas at the same time, and on the other hand, after the gas storage device 2 receives the upstream gas alone and then supplies gas to the downstream after a period of time, it can play a gas homogenization effect and improve the uniformity of the calorific value of the gas in the gas storage device 2.

[0040] In one embodiment, the capacity of the gas storage device 2 is 10,000 to 100,000 Nm 3 .

[0041] In one embodiment, if Figure 1 The gas main pipeline 1 is provided with a first monitoring position 11, which is located between the gas storage device 2 and the main flow regulating valve 13. A first gas calorific value monitoring unit 112 and a plurality of first pressure monitoring units 111 arranged in sequence along the gas flow direction are provided at the first monitoring position 11. The first gas calorific value monitoring unit 112 can be a calorific value meter, and the first pressure monitoring unit 111 can be a pressure monitoring device such as a pressure transmitter.

[0042] The first 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.

[0043] 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.

[0044] In one embodiment, the gas heat supply is calculated using the following formula:

[0045] Q 煤气 =qm 气

[0046] Wherein, q is the calorific value of the gas, which can be monitored in real time by the above-mentioned calorific value monitoring unit 112; m 气 It is the gas flow rate, which can be obtained by monitoring the gas pressure.

[0047] The gas calorific value monitoring unit 112 may be arranged on the same cross section of the gas main pipeline 1 opposite to one of the first pressure monitoring units 111 , or may be arranged between two adjacent first pressure monitoring units 111 , or may be arranged downstream of each first pressure monitoring unit 111 .

[0048] 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.

[0049] There is a certain distance between the first monitoring position 11 and the main flow regulating valve 13 to ensure that corresponding processing can be performed in advance when the gas fluctuates. In one embodiment, the distance between the first monitoring position 11 and the main flow regulating valve 13 is more than 20m, for example, controlled within the range of 20 to 100m.

[0050] There is a certain distance between the main flow regulating valve 13 and the boiler burner 5 , and the distance is preferably greater than 20 m, for example, in the range of 20 to 100 m.

[0051] The main flow regulating valve 13 is obviously an automatic valve, and a flow regulating valve such as an electric butterfly valve can be used.

[0052] In one embodiment, if Figure 1 The gas main pipeline 1 is also provided with a second monitoring position 12, which is located upstream of the gas storage device 2. A plurality of second pressure monitoring units 121 are sequentially provided at the monitoring position along the gas flow direction. By monitoring the upstream gas pressure through the second monitoring position 12, it is possible to timely understand whether the upstream gas pressure fluctuates, which is convenient for subsequent adjustment.

[0053] Furthermore, a second gas calorific value meter 122 is provided at the second monitoring position 12, which can monitor the calorific value of the gas online. The second gas calorific value meter 122 can be arranged on the same cross-section of the gas main pipeline 1 relative to one of the second pressure monitoring units 121, or can be arranged between two adjacent second pressure monitoring units 121, or can be arranged downstream of each second pressure monitoring unit 121.

[0054] Optionally, the gas main pipeline 1 is further provided with a bypass pipe 6, the two ends of which are respectively connected to the upstream and downstream of the gas storage device 2, and a bypass valve 62 is provided on the bypass pipe 6. Further, the inlet end of the bypass pipe 6 is located between the second monitoring position 12 and the gas storage device 2, and the outlet end of the bypass pipe 6 is located between the gas storage device 2 and the first monitoring position 11. In this scheme, according to the pressure fluctuation of the upstream gas, it can be selected to make the upstream gas enter the gas storage device 2 or directly supply it to the boiler burner 5. For example, when the gas fluctuation is within the allowable range, it can be directly supplied to the boiler burner 5.

[0055] The bypass valve 62 may be a cut-off valve.

[0056] Preferably, a bypass flow regulating valve 61 can be provided on the bypass pipe 6. Based on this design, part of the coal gas can flow through the bypass pipe 6 and part of the coal gas can enter the coal gas storage device 2, thereby reducing the flow impact on the coal gas storage device 2. When the upstream coal gas flow exceeds the gas storage margin of the coal gas storage device 2, the smoothness and safety of the system operation can be guaranteed; in one of the embodiments, a stable flow rate can be set through the bypass pipe 6. When the upstream coal gas has a positive fluctuation, the bypass pipe 6 maintains a normal coal gas flow rate, and the excess coal gas enters the coal gas storage device 2. The coal gas storage device 2 absorbs the coal gas increment, which can improve the stability of the system operation while reducing the impact on the coal gas storage device 2, and the regulation is also faster and more effective; when the upstream coal gas has a negative fluctuation, all the coal gas flows through the bypass pipe 6, and the fluctuation amount is supplemented by the coal gas storage device 2.

[0057] In one embodiment, if Figure 1 , the gas branch pipeline 4 is also provided with a branch flow regulating valve 41. A third pressure monitoring unit 42 can be further provided on the gas branch pipeline 4. By controlling the main flow regulating valve 13 on the gas main pipeline 1 and the branch flow regulating valve 41 on the gas branch pipeline 4, the controllability and control flexibility of the boiler gas flow can be further improved, thereby improving the operating stability of the supercritical gas boiler. In addition, a shut-off valve 43 is also provided on the gas branch pipeline 4, for example, a hydraulic shut-off valve is used, which can further improve the reliability of system operation.

[0058] 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.

[0059] Alternatively, if Figure 1 An electric blind plate valve 14 and a hydraulic quick-cut valve 15 are also provided on the gas main pipeline 1, which can further improve the reliability of system operation.

[0060] 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.

[0061] Embodiment 2

[0062] An embodiment of the present invention provides a method for controlling the stable operation of a supercritical gas boiler. The method is implemented based on the gas supply system of the supercritical gas boiler provided in the first embodiment.

[0063] The above methods include:

[0064] When the upstream gas pressure fluctuation is within the set fluctuation range, the upstream gas first enters the gas storage device 2 for buffering, and the gas storage device 2 supplies gas to the boiler burner 5, thereby achieving a first-level buffer for gas fluctuations, which can correspondingly improve the operating stability of the supercritical gas boiler.

[0065] Under normal working conditions, after the gas storage device 2 is added, the gas can be supplied to the boiler burner 5 relatively stably. However, when the upstream gas pressure fluctuates greatly, the gas pressure at the outlet of the gas storage device 2 may still fluctuate, and when the gas storage device 2 continuously inhales and exhausts gas, the internal gas calorific value may also fluctuate, which may cause the gas calorific value at the outlet of the gas storage device 2 to fluctuate. Therefore, when the upstream gas pressure fluctuates beyond the set fluctuation range and / or the gas calorific value at the outlet of the gas storage device 2 fluctuates, the gas flow is adjusted through the main flow regulating valve 13 on the basis of the primary buffer of the gas storage device 2, so as to achieve secondary regulation of gas fluctuation.

[0066] Among them, the upstream gas fluctuation can be realized through the above-mentioned second monitoring position 12.

[0067] Furthermore, regulating the gas flow rate through the main flow regulating valve 13 specifically includes:

[0068] A first monitoring position 11 is provided on the gas main pipeline 1, and the first monitoring position 11 is located between the gas storage device 2 and the main flow regulating valve 13. A gas calorific value monitoring unit 112 and a plurality of first pressure monitoring units 111 are provided at the first monitoring position 11 in sequence along the gas flow direction;

[0069] The gas pressure is monitored by each first pressure monitoring unit 111 at the first 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 first monitoring position 11 to the main flow regulating valve 13;

[0070] If ΔQ 煤气 >0, after time t1, the opening of the main flow regulating valve 13 is reduced to improve the stability of the main steam parameters of the gas boiler;

[0071] If ΔQ 煤气 <0, after time t1, the opening of the main flow regulating valve 13 is increased to improve the stability of the main steam parameters of the gas boiler;

[0072] If ΔQ 煤气 =0, keeping the opening of the main flow regulating valve 13 unchanged.

[0073] The setting of the first monitoring position 11 has been described in the above-mentioned embodiment 1 and will not be described in detail here.

[0074] In one embodiment, the gas heat supply is calculated using the following formula:

[0075] Q 煤气 =qm气

[0076] Where, q is the calorific value of gas; m 气 is the gas flow rate.

[0077] Furthermore, when calculating the time t1 required for the gas to run from the first monitoring position 11 to the main flow regulating valve 13, the position of the gas pressure measuring point at the center of the first monitoring position 11 or the center position of the first monitoring position 11 is used as the starting running position of the gas, and the gas flow rate can be calculated based on the gas pressure monitored at the starting running position and combined with the pipe diameter, etc.

[0078] Furthermore, when calculating ΔQ 煤气 When calculating the pressure difference between each two adjacent first pressure monitoring units 111, the gas pressure fluctuation amount is first obtained. Specifically, the pressure difference between each two adjacent first pressure monitoring units 111 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 two adjacent first pressure monitoring units 111, it is preferably the monitoring data of the downstream pressure monitoring unit minus the monitoring data of the upstream pressure monitoring unit. 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.

[0079] Obviously, the detection of gas fluctuations at the second monitoring position 12 can refer to the detection method at the first monitoring position 11, so it will not be described in detail.

[0080] Further preferably, when adjusting the opening of the main flow regulating valve 13, 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.

[0081] In the case where the gas calorific value does not fluctuate much, preferably, for every 1 KPa drop or rise in the gas pressure, the opening of the main flow regulating valve 13 increases or decreases by 1% to 10% accordingly.

[0082] Further preferably, the method further comprises:

[0083] When the main flow regulating valve 13 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.

[0084] 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:

[0085] Q 水 =ηQ 煤气

[0086] Among them, Q 水 is the heat absorbed by the feed water heat exchange; η is the boiler thermal efficiency.

[0087] Q 水 =m 水 (h out -h in )

[0088] 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 .

[0089] Therefore, the calculation formula for the boiler main feed water flow is:

[0090]

[0091] 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 13, the boiler thermal efficiency η is recalculated, and the specific calculation method is a conventional technology in the field and is not described here.

[0092] Accordingly, the adjustment amount of the boiler main feed water flow is calculated according to the following formula:

[0093]

[0094] 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.

[0095] 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.

[0096] Furthermore, the method further comprises:

[0097] Obtain the time t2 required for the gas to be transmitted from the first monitoring position 11 to the boiler burner 5 and the time t3 required for the feed water to be transmitted from the feed water pump to the boiler water wall,

[0098] If t2>t3, the main feed water flow of the boiler is adjusted with a lag time of t2-t3;

[0099] 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.

[0100] 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.

[0101] In one embodiment, the method further comprises:

[0102] A bypass pipe 6 is provided on the gas main pipeline 1, and the two ends of the bypass pipe 6 are respectively connected to the upstream and downstream of the gas storage device 2, and a bypass valve 62 is provided on the bypass pipe 6;

[0103] The gas pressure fluctuation is monitored upstream of the gas storage device 2. When the upstream gas pressure does not fluctuate or the upstream gas pressure fluctuation is within the allowable fluctuation range, the upstream gas runs directly through the bypass pipe 6; when the gas pressure fluctuates, the upstream gas enters the gas storage device 2.

[0104] The arrangement of the bypass pipe 6 has been described in the above-mentioned first embodiment and will not be described in detail here.

[0105] Regarding the above-mentioned allowable fluctuation range, in one embodiment, based on the normal gas flow, the gas flow fluctuation amount Δm 气 When it is in the range of 0 to 6%, it can be considered that the upstream gas pressure fluctuation is within the allowable fluctuation range.

[0106] The above-mentioned fluctuation range can be determined according to specific working conditions and system design parameters. In the above-mentioned scheme with bypass pipe 6, optionally, on the basis of normal gas flow, the gas flow fluctuation amount Δm 气 When it is in the range of 6-40%, it can be considered that the upstream gas pressure fluctuation is within the set fluctuation range.

[0107] When the upstream gas passes directly through the bypass pipe 6, the inlet and outlet of the gas storage device 2 are preferably closed; when the upstream gas enters the gas storage device 2, the bypass pipe 6 is preferably closed.

[0108] In another embodiment, as described in the above-mentioned embodiment 1, a bypass flow regulating valve 61 is provided on the bypass pipe 6, so that part of the gas can flow through the bypass pipe 6 and part of the gas can enter the gas storage device 2, thereby reducing the flow impact on the gas storage device 2. When the upstream gas flow exceeds the gas storage margin of the gas storage device 2, the smoothness and safety of the system operation can be ensured. Preferably, a stable flow rate can be set through the bypass pipe 6. When the upstream gas has a positive fluctuation, the bypass pipe 6 maintains a normal gas flow rate, and the excess gas enters the gas storage device 2. The gas storage device 2 absorbs the gas increment, which can improve the stability of the system operation while reducing the impact on the gas storage device 2, and the regulation is also faster and more effective; when the upstream gas has a negative fluctuation, the gas is all circulated through the bypass pipe 6, and the fluctuation is supplemented by the gas storage device 2.

[0109] In addition, when the gas storage device 2 fails or is undergoing maintenance, the upstream gas can be directly passed through the bypass pipe 6, thereby ensuring the smooth operation and safety of the system; moreover, in this operating condition, when the upstream gas fluctuates, the operating stability of the supercritical gas boiler can still be ensured by adjusting the main flow regulating valve 13 and by adjusting the main feed water flow of the boiler. The above-mentioned adjustment methods of the main flow regulating valve 13 are applicable to this operating condition and will not be repeated here.

[0110] 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 is implemented based on the gas supply system of the supercritical gas boiler; The gas supply system of the supercritical gas boiler includes a gas main pipeline and a plurality of gas branch pipelines connected to each boiler burner in a one-to-one correspondence. A gas storage device and a main flow regulating valve are provided on the gas main pipeline, and the main flow regulating valve is located downstream of the gas storage device; The method comprises: When the upstream gas pressure fluctuation is within the set fluctuation range, the upstream gas first enters the gas storage device for buffering, and the gas storage device supplies gas to the boiler burner to achieve a primary buffer for gas fluctuations; When the upstream gas pressure fluctuation exceeds the set fluctuation range and / or the gas calorific value at the outlet of the gas storage device fluctuates, the gas flow is adjusted by the main flow regulating valve on the basis of the primary buffer of the gas storage device to achieve secondary regulation of gas fluctuations; Regulating the gas flow rate by the main flow regulating valve specifically includes: A first monitoring position is arranged on the gas main pipeline, the first monitoring position is located between the gas storage device and the main flow regulating valve, and a gas calorific value monitoring unit and a plurality of first pressure monitoring units arranged in sequence along the gas flow direction are arranged at the first monitoring position; The gas pressure is monitored by each first pressure monitoring unit at the first monitoring position, 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 first monitoring position to the main flow regulating valve; 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; The method further comprises: 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: The gas branch pipeline is also provided with a branch flow regulating valve; Obtain the time t2 required for gas to be transmitted from the first 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; 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: The method further comprises: A bypass pipe is arranged on the gas main pipeline, the two ends of the bypass pipe are respectively connected to the upstream and downstream of the gas storage device, and a bypass valve is arranged on the bypass pipe; Monitoring gas pressure fluctuations upstream of the gas storage device, when the upstream gas pressure does not fluctuate or the upstream gas pressure fluctuation is within the allowable fluctuation range, the upstream gas directly flows through the bypass pipe; when the gas pressure fluctuation exceeds the allowable fluctuation range, the upstream gas enters the gas storage device; And / or, a bypass flow regulating valve is arranged on the bypass pipe, and a stable flow rate is set through the bypass pipe. When the upstream gas pressure fluctuates positively, the bypass pipe maintains a normal gas flow rate, and the excess gas enters the gas storage device; when the upstream gas pressure fluctuates negatively, all the gas flows through the bypass pipe, and the fluctuation amount is supplemented by the gas storage device.

3. The method for controlling the stable operation of a supercritical gas boiler according to claim 1, characterized in that: A second monitoring position is also provided on the gas main pipeline. The second monitoring position is located upstream of the gas storage device. A plurality of second pressure monitoring units are sequentially provided at the monitoring position along the gas flow direction.

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