System and method for coupling gas turbine exhaust with coal-fired boiler air distribution

Abstract

The present disclosure relates to a system and method for coupling flue gas from a gas turbine with air distribution of a coal-fired boiler, the system comprising: a flue gas duct for communicating with a secondary air duct of the coal-fired boiler to introduce flue gas discharged from the gas turbine into the secondary air duct of the coal-fired boiler and mix with secondary air in the secondary air duct to obtain mixed secondary air; and a secondary air adjusting device arranged at a nozzle of the secondary air duct to adjust an air volume of the mixed secondary air injected into a furnace of the coal-fired boiler. The system for coupling flue gas from a gas turbine with air distribution of a coal-fired boiler provided by the present disclosure can introduce flue gas discharged from the gas turbine into the coal-fired boiler and ensure normal operation of the coal-fired boiler.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of coal-fired power generation technology, in particular, to a system and method for coupling flue gas discharged by a gas turbine with air distribution of a coal-fired boiler. BACKGROUND

[0002] With the implementation of the national double carbon policy, the diversity of energy supply in China proposes to significantly increase the proportion of natural gas consumption, accelerate the development of natural gas power generation, and prioritize the construction of gas-steam combined cycle cogeneration units in cities with good economic foundation and guaranteed gas supply, increasing the proportion of natural gas in energy consumption to 12-14%. It is understood that the flue gas discharged by the gas turbine has a relatively high temperature, about 610℃, which contains a large amount of available heat energy. Fully utilizing this heat energy and coupling combustion with the original coal-fired unit can not only bring good economic benefits to the enterprise, but also reduce carbon emissions of the coal-fired unit. However, in related technologies, when the flue gas discharged by the gas turbine is introduced into the coal-fired boiler, it often affects the performance of the coal-fired boiler itself, seriously affecting the normal operation of the coal-fired boiler. SUMMARY

[0003] The purpose of the present disclosure is to provide a system and method for coupling flue gas discharged by a gas turbine with air distribution of a coal-fired boiler, which can introduce flue gas discharged by the gas turbine into the coal-fired boiler and ensure the normal operation of the coal-fired boiler.

[0004] To achieve the above purpose, the present disclosure provides a system for coupling flue gas discharged by a gas turbine with air distribution of a coal-fired boiler, comprising: a flue gas pipeline for communicating with a secondary air duct of a coal-fired boiler to introduce flue gas discharged by a gas turbine into the secondary air duct of the coal-fired boiler and mix with secondary air in the secondary air duct to obtain mixed secondary air; and a secondary air adjusting device for being arranged at a nozzle of the secondary air duct to adjust the amount of air of the mixed secondary air injected into a hearth of the coal-fired boiler.

[0005] Optionally, the secondary air adjusting device comprises a secondary air box and an air port adjusting assembly, the secondary air box is through in the length direction to form a jet channel, one end of the jet channel is used for communicating with the secondary air duct, and the other end is used for being introduced into the hearth, and the air port adjusting assembly is slidably arranged on the secondary air box to adjust the cross-sectional size of the jet channel.

[0006] Optionally, the air port adjusting assembly comprises a partition plate and an air port adjusting plate, the partition plate extends along the length direction of the injection channel to separate the injection channel into an air inlet channel and an adjusting channel, the air port adjusting plate is fixed at one end of the partition plate and blocks the adjusting channel, an adjusting pull rod is fixed on the air port adjusting plate, the adjusting pull rod drives the air port adjusting plate and the partition plate to reciprocate along a direction perpendicular to the injection channel to adjust the size of the air inlet channel and the adjusting channel.

[0007] Optionally, the flue gas duct comprises a flue gas main duct and a plurality of flue gas branch ducts in communication with the flue gas main duct, the flue gas main duct is configured to communicate with the flue gas outlet of the gas turbine, and the plurality of flue gas branch ducts are respectively configured to communicate with the plurality of secondary air channels of the coal-fired boiler, so that the flue gas discharged by the gas turbine is respectively introduced into the plurality of secondary air channels of the coal-fired boiler through the flue gas main duct and the plurality of flue gas branch ducts, and mixed with the secondary air in the plurality of secondary air channels to obtain mixed secondary air.

[0008] Optionally, the system further comprises a flue gas mixing device, the flue gas branch duct comprises a flue gas conveying section configured to be arranged in the secondary air channel, and the flue gas mixing device is configured as a plurality of flue gas conveying through-holes formed in the pipe wall of the flue gas conveying section.

[0009] Optionally, the system further comprises an exhaust air fan, and the flue gas duct is configured to communicate with the gas turbine through the exhaust air fan.

[0010] On the basis of the above technical solutions, the present disclosure further provides a method for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler, which is applicable to the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler. The method comprises the following steps: determining an actual first secondary air amount and a first coal-burning amount required by a coal-fired boiler according to a first gas turbine flue gas amount introduced into a secondary air channel of the coal-fired boiler by a gas turbine; determining a first boiler flue gas amount actually discharged by the coal-fired boiler according to the first gas turbine flue gas amount, a preset primary air amount, the first secondary air amount, and the first coal-burning amount; the preset primary air amount is a primary air amount required by the coal-fired boiler for combustion under operating load; determining a target gas turbine flue gas amount actually introduced into the coal-fired boiler by the gas turbine according to the first boiler flue gas amount and a preset boiler flue gas amount; the preset boiler flue gas amount is a flue gas amount generated by the coal-fired boiler for combustion under operating load.

[0011] Optionally, the method further comprises: determining the actual required first secondary air quantity and the actual required first coal quantity of the coal-fired boiler according to the first gas turbine flue gas quantity introduced into the secondary air duct of the coal-fired boiler, the preset primary air quantity, and the preset total oxygen quantity; the preset total oxygen quantity is the total oxygen quantity required by the coal-fired boiler for combustion under the operating load; determining the actual required first coal quantity of the coal-fired boiler according to the change value of the enthalpy of the first gas turbine flue gas quantity within a preset time period, the calorific value of the coal quality required by the coal-fired boiler, and the preset total coal quantity; the preset total coal quantity is the total coal quantity required by the coal-fired boiler for combustion under the operating load.

[0012] Optionally, the method further comprises: determining the actual required first secondary air quantity and the actual required first coal quantity of the coal-fired boiler according to the first gas turbine flue gas quantity introduced into the secondary air duct of the coal-fired boiler, the preset primary air quantity, and the preset total oxygen quantity; the preset total oxygen quantity is the total oxygen quantity required by the coal-fired boiler for combustion under the operating load; determining the actual required first coal quantity of the coal-fired boiler according to the change value of the enthalpy of the first gas turbine flue gas quantity within a preset time period, the calorific value of the coal quality required by the coal-fired boiler, and the preset total coal quantity; the preset total coal quantity is the total coal quantity required by the coal-fired boiler for combustion under the operating load.

[0013] Optionally, the method further comprises: determining the actual required first secondary air quantity and the actual required first coal quantity of the coal-fired boiler according to the first gas turbine flue gas quantity introduced into the secondary air duct of the coal-fired boiler, the preset primary air quantity, and the preset total oxygen quantity; the preset total oxygen quantity is the total oxygen quantity required by the coal-fired boiler for combustion under the operating load; determining the actual required first coal quantity of the coal-fired boiler according to the change value of the enthalpy of the first gas turbine flue gas quantity within a preset time period, the calorific value of the coal quality required by the coal-fired boiler, and the preset total coal quantity; the preset total coal quantity is the total coal quantity required by the coal-fired boiler for combustion under the operating load.

[0014] Optionally, the determining the target gas turbine flue gas amount actually introduced into the coal-fired boiler according to the first boiler flue gas amount and the preset boiler flue gas amount comprises: in a case that the first boiler flue gas amount actually discharged by the coal-fired boiler is greater than or equal to a preset proportion threshold of the preset boiler flue gas amount, reducing the first gas turbine flue gas amount introduced into the secondary air duct of the coal-fired boiler by the gas turbine; and cyclically performing a flue gas amount adjusting step until a preset termination condition is met; the flue gas amount adjusting step comprises: determining the second secondary air amount actually required by the coal-fired boiler and the second coal combustion amount according to the first gas turbine flue gas amount introduced into the secondary air duct of the coal-fired boiler by the gas turbine; determining the second boiler flue gas amount actually discharged by the coal-fired boiler according to the first gas turbine flue gas amount, the preset primary air amount, the second secondary air amount and the second coal combustion amount; determining the second gas turbine flue gas amount actually introduced into the coal-fired boiler according to the second boiler flue gas amount and the preset boiler flue gas amount; taking the second gas turbine flue gas amount as the new first gas turbine flue gas amount; and wherein the preset termination condition is that the first boiler flue gas amount actually discharged by the coal-fired boiler is less than the preset proportion threshold of the preset boiler flue gas amount.

[0015] By the above technical solution, in the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler provided by the present disclosure, the flue gas discharged by the gas turbine is introduced into the secondary air duct of the coal-fired boiler through the flue gas discharge pipeline, and the flue gas is mixed with the secondary air in the secondary air duct to obtain mixed secondary air; the air amount of the mixed secondary air sprayed into the furnace of the coal-fired boiler is adjusted through the secondary air adjusting device arranged at the spray port of the secondary air duct. Since the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler provided by the present disclosure can adjust the air amount of the mixed secondary air through the secondary air adjusting device arranged at the spray port of the secondary air duct while introducing the flue gas discharged by the gas turbine into the secondary air duct of the coal-fired boiler, the mixed secondary air sprayed into the furnace can be regulated according to the actual combustion demand of the coal-fired boiler, so that the normal operation of the coal-fired boiler can be ensured even if the flue gas discharged by the gas turbine is introduced into the system. Moreover, since the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler makes full use of the flue gas discharged by the gas turbine, the carbon dioxide emission amount of the gas turbine can be reduced.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation of the present disclosure. In the drawings:

[0018] Figure 1is a use state diagram of a flue gas of a gas turbine and air distribution coupled system of a coal-fired boiler of the present disclosure;

[0019] Figure 2 is a structural schematic diagram of a secondary air adjusting device in the flue gas of a gas turbine and air distribution coupled system of a coal-fired boiler of the present disclosure;

[0020] Figure 3 is another structural schematic diagram of a secondary air adjusting device in the flue gas of a gas turbine and air distribution coupled system of a coal-fired boiler of the present disclosure;

[0021] Figure 4 is a flow chart of a method of coupling flue gas of a gas turbine and air distribution of a coal-fired boiler of the present disclosure.

[0022] BRIEF DESCRIPTION OF DRAWINGS

[0023] 1-flue gas pipeline; 11-flue gas main pipeline; 12-flue gas branch pipeline; 121-flue gas feeding section; 2-coal-fired boiler; 21-secondary air duct; 22-furnace; 3-gas turbine; 4-secondary air adjusting device; 41-secondary air box; 411-injection channel; 411a-air inlet channel; 411b-adjusting channel; 42-air port adjusting assembly; 421-separation plate; 422-air port adjusting plate; 423-adjusting pull rod; 5-exhaust air fan. DETAILED DESCRIPTION

[0024] The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0025] In the present disclosure, the orientation words such as "inner" and "outer" used herein refer to "inner" and "outer" with respect to the outline of the corresponding component itself. In addition, the terms "first", "second", etc. used in the present disclosure are used to distinguish one element from another element, and do not have sequentiality and importance. In addition, in the following description, the same reference numerals in different drawings represent the same or similar elements unless otherwise explained. The above definitions are only used to explain and illustrate the present disclosure, and should not be understood as limiting the present disclosure.

[0026] The present disclosure provides a system for coupling flue gas of a gas turbine and air distribution of a coal-fired boiler, as shown in Figure 1 , comprising: a flue gas pipeline 1 for communicating with a secondary air duct 21 of a coal-fired boiler 2, so as to pass the flue gas discharged by a gas turbine 3 into the secondary air duct 21 of the coal-fired boiler 2 and mix with the secondary air in the secondary air duct 21 to obtain mixed secondary air; and a secondary air adjusting device 4 arranged at the injection port of the secondary air duct 21, for adjusting the air volume of the mixed secondary air injected into the furnace 22 of the coal-fired boiler 2.

[0027] Through the technical scheme, in the system for coupling flue gas of a gas turbine and air distribution of a coal-fired boiler provided by the disclosure, the flue gas discharged by the gas turbine 3 is introduced into the secondary air duct 21 of the coal-fired boiler 2 through the flue gas pipeline 1, and the flue gas is mixed with the secondary air in the secondary air duct 21 to obtain mixed secondary air; the air volume of the mixed secondary air sprayed into the hearth 22 of the coal-fired boiler 2 is adjusted through the secondary air adjusting device 4 arranged at the injection port of the secondary air duct 21. Since the system for coupling flue gas of a gas turbine and air distribution of a coal-fired boiler can adjust the air volume of the mixed secondary air through the secondary air adjusting device 4 arranged at the injection port of the secondary air duct 21 while introducing the flue gas of the gas turbine 3 into the secondary air duct 21 of the coal-fired boiler 2, the mixed secondary air sprayed into the hearth 22 can be adjusted according to the actual combustion demand of the coal-fired boiler 2, so that the normal operation of the coal-fired boiler 2 can be ensured even if the flue gas discharged by the gas turbine 3 is introduced into the system. Moreover, since the system for coupling flue gas of a gas turbine and air distribution of a coal-fired boiler makes full use of the flue gas discharged by the gas turbine 3, the carbon dioxide emission of the gas turbine 3 can be reduced.

[0028] In addition, in the system for coupling flue gas of a gas turbine and air distribution of a coal-fired boiler, the flue gas in the gas turbine 3 is introduced into the secondary air duct 21 of the coal-fired boiler 2 through the flue gas pipeline 1, so that the flue gas amount introduced into the coal-fired boiler 2 by the gas turbine 3 can be directly adjusted by arranging an adjusting valve at a suitable position such as the inside, the inlet, or the outlet of the flue gas pipeline 1, and the flue gas passage for connecting the gas turbine 3 and the coal-fired boiler 2 can be blocked by closing the adjusting valve when the flue gas in the gas turbine 3 is not introduced into the coal-fired boiler 2, so that the gas turbine 3 and the coal-fired boiler 2 can be completely independent and normally operated.

[0029] In the specific embodiment provided by the disclosure, reference is made to FIGS. 1 to 4. Figure 1 Figure 2 As shown in FIGS. 1 to 4, the secondary air adjusting device 4 includes a secondary air box 41 and an air port adjusting assembly 42. The secondary air box 41 is through in the length direction to form a spraying channel 411, one end of the spraying channel 411 is used to communicate with the secondary air duct 21, and the other end is used to communicate into the hearth 22. The air port adjusting assembly 42 is slidably arranged on the secondary air box 41 to adjust the cross-sectional size of the spraying channel 411. Through such arrangement, the cross-sectional size of the spraying channel 411 can be changed according to the sliding of the air port adjusting assembly 42, so as to adjust the air volume of the mixed secondary air communicated into the hearth 22 of the coal-fired boiler 2 in the secondary air duct 21.

[0030] In the specific embodiment provided by the disclosure, reference is made to FIGS. 1 to 4. Figure 2 Figure 3 ​​As shown, the air port adjusting assembly 42 comprises a partition plate 421 and an air port adjusting plate 422, the partition plate 421 extends along the length direction of the injection channel 411 to divide the injection channel 411 into an air inlet channel 411a and an adjusting channel 411b, the air port adjusting plate 422 is fixedly arranged at one end of the partition plate 421 and blocks the adjusting channel 411b, an adjusting pull rod 423 is fixedly arranged on the air port adjusting plate 422, the adjusting pull rod 423 drives the air port adjusting plate 422 and the partition plate 421 to reciprocate along the direction perpendicular to the injection channel 411 to adjust the size of the air inlet channel 411a and the adjusting channel 411b. Through such arrangement, the mixed secondary air obtained by mixing the flue gas of the gas turbine 3 and the secondary air of the coal-fired boiler 2 can flow through the air inlet channel 411a, so that when the size of the air inlet channel 411a and the adjusting channel 411b is changed by driving the air port adjusting plate 422 by the pull rod, the flow size and the flow speed of the mixed secondary air entering into the furnace 22 through the air inlet channel 411a can be adjusted, and the adjustment of the air volume and the flow speed of the mixed secondary air according to the actual needs of the coal-fired boiler 2 can be realized.

[0031] It should be noted that the partition plate 421 in the air port adjusting assembly 42 described above can also be independent of the air port adjusting plate 422, that is, the partition plate 421 is fixedly arranged in the injection channel 411, and the air port adjusting plate 422 can reciprocate relative to the partition plate 421 along the direction perpendicular to the injection channel 411 to adjust the size of the air inlet channel 411a and the adjusting channel 411b divided by the partition plate 421 respectively.

[0032] In the specific embodiments provided in the present disclosure, reference is made to Figure 1 As shown, the flue gas exhaust pipeline 1 comprises a flue gas exhaust main pipeline 11 and a plurality of flue gas exhaust branch pipelines 12 in communication with the flue gas exhaust main pipeline 11, the flue gas exhaust main pipeline 11 is used to communicate with the flue gas exhaust port of the gas turbine 3, and the plurality of flue gas exhaust branch pipelines 12 are respectively used to communicate with the plurality of secondary air channels 21 of the coal-fired boiler 2, so that the flue gas exhausted by the gas turbine 3 is correspondingly introduced into the plurality of secondary air channels 21 of the coal-fired boiler 2 through the flue gas exhaust main pipeline 11 and the plurality of flue gas exhaust branch pipelines 12, and mixed with the secondary air in the plurality of secondary air channels 21 to obtain mixed secondary air. In this way, not only can the flue gas exhausted by the gas turbine 3 be introduced into the plurality of secondary air channels 21 of the coal-fired boiler 2 and mixed with the secondary air in the plurality of secondary air channels 21 at the same time, but also the efficiency of introducing the flue gas of the gas turbine 3 into the secondary air channels 21 of the coal-fired boiler 2 can be improved, so that the flue gas of the gas turbine 3 can be quickly mixed with the flue gas in each secondary air channel 21.

[0033] In the specific embodiments provided in the present disclosure, reference is made to Figure 1As shown, the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler further comprises a flue gas mixing device, the flue gas exhaust sub-pipe 12 comprises a flue gas feeding section 121 arranged in the secondary air duct 21, and the flue gas mixing device is configured as a plurality of flue gas feeding through-holes formed in the pipe wall of the flue gas feeding section 121, through which the flue gas can enter into the flue gas feeding section 121 through the plurality of flue gas feeding through-holes to achieve uniform mixing of the flue gas and the secondary air. Here, to further improve the mixing effect of the flue gas and the secondary air, diffusion nozzles with mixing or jetting effect, such as Venturi nozzles, can also be added at the flue gas feeding through-holes.

[0034] In the detailed description provided in the present disclosure, reference is made to Figure 1 As shown, the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler further comprises an exhaust air fan 5, and the flue gas pipe 1 is connected to the gas turbine 3 through the exhaust air fan 5. Since the exhaust air fan 5 is a fan capable of lifting the fluid head, overcoming the fluid flow resistance, and improving the medium conveying capacity, a negative pressure can be formed at the suction inlet, so that the flue gas exhausted by the gas turbine 3 can be quickly introduced into the secondary air duct 21 of the coal-fired boiler 2 by using the exhaust air fan 5.

[0035] On the basis of the above technical solution, the present disclosure further provides a method for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler, which is applicable to the system for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler described above, and reference is made to Figure 4 As shown, the method for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler comprises the following steps: determining the actual first secondary air amount and the first coal-burning amount required by the coal-fired boiler 2 according to the first turbine flue gas amount introduced by the gas turbine 3 into the secondary air duct 21 of the coal-fired boiler 2; determining the first boiler flue gas amount actually exhausted by the coal-fired boiler 2 according to the first turbine flue gas amount, the preset primary air amount, the first secondary air amount, and the first coal-burning amount; the preset primary air amount is the primary air amount required by the coal-fired boiler 2 for combustion under the operating load; determining the target turbine flue gas amount actually introduced by the gas turbine 3 into the coal-fired boiler 2 according to the first boiler flue gas amount and the preset boiler flue gas amount; the preset boiler flue gas amount is the flue gas amount generated by the coal-fired boiler 2 for combustion under the operating load.

[0036] In the above technical solution, since the flue gas discharged by the gas turbine 3 has a high temperature, about 610℃, it contains a large amount of available heat energy, and the flue gas also contains a large amount of oxygen, so that fully utilizing the heat energy and oxygen in the flue gas to assist the combustion of coal in the furnace 22 of the coal-fired boiler 2 has good economic benefits. However, in order to avoid affecting the normal combustion of coal in the furnace 22 of the coal-fired boiler 2 due to the introduction of flue gas from the gas turbine 3, it is necessary to reasonably adjust the amount of flue gas introduced from the gas turbine 3 to the coal-fired boiler 2 according to the actual situation of the coal-fired boiler 2, that is, it is necessary to reasonably adjust the target amount of flue gas introduced from the gas turbine 3 to the coal-fired boiler 2 according to the actual situation of the coal-fired boiler 2. In the method for coupling flue gas from the gas turbine and air supply from the coal-fired boiler provided in the present disclosure, the first amount of flue gas introduced from the gas turbine 3 into the secondary air duct 21 of the coal-fired boiler 2 is used to first determine the actual first amount of secondary air required by the coal-fired boiler 2 and the first amount of coal to be burned, and then the first amount of flue gas, the first amount of secondary air, the preset amount of primary air, and the first amount of coal to be burned are used to determine the actual first amount of flue gas generated by the coal-fired boiler 2 when the amount of flue gas introduced from the gas turbine 3 to the coal-fired boiler 2 is the first amount of flue gas, and finally the target amount of flue gas actually required to be introduced into the coal-fired boiler 2 is determined according to the relationship between the first amount of flue gas and the preset amount of flue gas.

[0037] In the specific embodiment provided in the present disclosure, determining the actual first amount of secondary air required by the coal-fired boiler 2 and the first amount of coal to be burned according to the first amount of flue gas introduced from the gas turbine 3 into the secondary air duct 21 of the coal-fired boiler 2 includes: determining the actual first amount of secondary air required by the coal-fired boiler 2 according to the first amount of flue gas, the preset amount of primary air, and the preset total oxygen amount; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler 2 to burn under the operating load; determining the actual first amount of coal to be burned by the coal-fired boiler 2 according to the change value of enthalpy of the first amount of flue gas within a preset time period, the calorific value of the coal to be burned by the coal-fired boiler 2, and the preset total coal amount; the preset total coal amount is the total coal amount required by the coal-fired boiler 2 to burn under the operating load. Here, since the flue gas discharged by the gas turbine 3 contains a large amount of oxygen, and the preset primary air and secondary air also contain a large amount of oxygen, the first amount of flue gas, the preset amount of primary air, and the preset total oxygen amount can be used to determine the size of the actual first amount of secondary air required by the coal-fired boiler 2. Similarly, since the flue gas discharged by the gas turbine 3 also contains a large amount of heat, and the coal to be burned has a certain calorific value, the actual first amount of coal to be burned can be obtained by the change value of enthalpy of the first amount of flue gas within a preset time period, the calorific value of the coal to be burned by the coal-fired boiler 2, and the preset total coal amount.

[0038] The method comprises the following steps: determining the actual required first and secondary air quantity of the coal-fired boiler 2 according to the first gas turbine flue gas quantity, the preset primary air quantity, and the preset total oxygen quantity, which comprises the following steps: determining the oxygen content in the preset primary air quantity according to the preset primary air quantity; determining the oxygen content in the preset secondary air quantity according to the preset secondary air quantity; obtaining the flue gas composition and the flue gas quantity of the first gas turbine flue gas quantity, and determining the oxygen content in the first gas turbine flue gas quantity according to the flue gas composition and the flue gas quantity of the first gas turbine flue gas quantity; comparing the sum of the oxygen content in the first gas turbine flue gas quantity and the oxygen content in the preset primary air quantity with the preset total oxygen quantity, if the comparison result is less than the preset total oxygen quantity, determining the actual required first and secondary air quantity of the coal-fired boiler 2 according to the lacking oxygen quantity and the oxygen content in the preset secondary air quantity; if the comparison result is greater than the preset total oxygen quantity, no secondary air needs to be supplemented; the preset total oxygen quantity is the total oxygen quantity required for the coal-fired boiler 2 to burn under the operating load. Here, the actual required first and secondary air quantity is calculated by separately obtaining the oxygen content in the preset primary air quantity, the preset secondary air quantity, and the first gas turbine flue gas quantity, and the secondary air entering the coal-fired boiler 2 is adjusted to ensure the normal combustion of coal in the furnace 22 of the coal-fired boiler 2.

[0039] The method comprises the following steps: determining the actual required first coal-burning quantity of the coal-fired boiler 2 according to the change value of the enthalpy value of the first gas turbine flue gas quantity in the preset time period, the heat value of the coal quality required by the coal-fired boiler 2 to burn, and the preset total coal quantity, which comprises the following steps: obtaining the change value of the enthalpy value of the first gas turbine flue gas quantity discharged by the gas turbine 3 in the preset time period and the heat value of the coal quality required by the coal-fired boiler 2 to burn, and converting the first gas turbine flue gas quantity into the second coal-burning quantity of the coal-fired boiler 2 according to the change value of the enthalpy value and the heat value of the coal quality; determining the actual required first coal-burning quantity of the coal-fired boiler 2 according to the difference between the preset total coal quantity and the second coal-burning quantity. Since the flue gas discharged by the gas turbine 3 contains a large amount of heat energy, the change value of the enthalpy value of the first gas turbine flue gas quantity in the preset time period is calculated, and the first gas turbine flue gas quantity is converted into the second coal-burning quantity of the coal-fired boiler 2 according to the change value of the enthalpy value and the heat value of the coal quality, so as to fully utilize the heat energy in the flue gas discharged by the gas turbine 3.

[0040] The method comprises the following steps: determining the target flue gas amount of the gas turbine 3 introduced into the coal-fired boiler 2 according to the first boiler flue gas amount and the preset boiler flue gas amount; and adjusting the flue gas amount of the gas turbine 3 introduced into the coal-fired boiler 2 according to the target flue gas amount of the gas turbine 3 introduced into the coal-fired boiler 2. The step of determining the target flue gas amount of the gas turbine 3 introduced into the coal-fired boiler 2 according to the first boiler flue gas amount and the preset boiler flue gas amount comprises the following steps: in the case that the first boiler flue gas amount actually discharged by the coal-fired boiler 2 is greater than or equal to a preset proportion threshold of the preset boiler flue gas amount, reducing the first flue gas amount of the gas turbine 3 introduced into the secondary air duct 21 of the coal-fired boiler 2; and cyclically performing the flue gas amount adjustment step until a preset termination condition is met. The flue gas amount adjustment step comprises the following steps: determining the second secondary air amount and the second coal combustion amount actually required by the coal-fired boiler 2 according to the first flue gas amount of the gas turbine 3 introduced into the secondary air duct 21 of the coal-fired boiler 2; determining the second boiler flue gas amount actually discharged by the coal-fired boiler 2 according to the first flue gas amount of the gas turbine 3, the preset primary air amount, the second secondary air amount and the second coal combustion amount; determining the second flue gas amount of the gas turbine 3 actually introduced into the coal-fired boiler 2 according to the second boiler flue gas amount and the preset boiler flue gas amount; and taking the second flue gas amount of the gas turbine 3 as the new first flue gas amount of the gas turbine 3; wherein the preset termination condition is that the first boiler flue gas amount actually discharged by the coal-fired boiler 2 is less than the preset proportion threshold of the preset boiler flue gas amount.

[0041] In the above technical solution, since the flue gas discharged by the gas turbine 3 contains a large amount of heat and oxygen, the actual required secondary air amount and the coal combustion amount of the coal-fired boiler 2 can be calculated by the flue gas amount of the gas turbine 3 introduced into the secondary air duct 21 of the coal-fired boiler 2, and then the actual flue gas amount of the coal-fired boiler 2 can be calculated according to the preset primary air amount of the coal-fired boiler 2, the actual required secondary air amount, the coal combustion amount and the flue gas amount of the gas turbine 3. If the actual flue gas amount of the coal-fired boiler 2 is greater than the preset proportion threshold compared with the preset boiler flue gas amount, the flue gas amount of the gas turbine 3 introduced into the coal-fired boiler 2 is adjusted cyclically until the actual flue gas amount of the coal-fired boiler 2 is less than the preset proportion threshold. In this way, the flue gas of the gas turbine 3 introduced into the coal-fired boiler 2 can be effectively utilized without affecting the normal operation of the coal-fired boiler 2.

[0042] It should be noted that the preset proportion threshold can be flexibly set according to the actual situation. Alternatively, the preset proportion threshold can be 10% of the preset boiler flue gas amount.

[0043] The method for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler provided by the present disclosure will be described in detail below through specific embodiments.

[0044] It should be noted that in the present embodiment, two 330MW supercritical tangential boilers and one GE6F.03 gas turbine are provided. The parameters of the supercritical tangential boilers are shown in Table 1-1, the parameters of the gas turbine are shown in Table 1-2, and the parameters of the gas turbine and the supercritical tangential boiler (i.e. the coal-fired boiler) calculated according to the method for coupling flue gas of a gas turbine with air distribution of a coal-fired boiler are shown in Table 1-3.

[0045] In this embodiment, firstly, the required primary air flow, the required secondary air flow, the total coal amount and the exhaust gas amount of the supercritical tangentially fired boiler (i.e. coal-fired boiler) during normal operation at rated load and average load are obtained, wherein the primary air flow, the secondary air flow and the total coal amount are obtained by actual measurement, and the exhaust gas amount is actually equal to the flue gas flow at the inlet of the air preheater, so the flue gas flow at the inlet of the air preheater can be detected to obtain the exhaust gas amount of the supercritical tangentially fired boiler.

[0046] Secondly, since the main influence on the normal operation of the supercritical tangentially fired boiler (i.e. coal-fired boiler) when the flue gas of the gas turbine is introduced into the supercritical tangentially fired boiler is the large amount of heat energy and oxygen contained in the flue gas of the gas turbine, the flue gas amount and composition of the flue gas of the gas turbine are measured in actual calculation, and the heat energy and oxygen provided by the flue gas of the gas turbine for the supercritical tangentially fired boiler are calculated according to the flue gas amount and composition, then the actual heat input required by the supercritical tangentially fired boiler is adjusted by the difference between the total heat required by the supercritical tangentially fired boiler during normal operation and the total heat contained in the flue gas of the gas turbine, and the heat is generated by coal combustion, so the actual coal amount required by the supercritical tangentially fired boiler can be calculated according to the actual heat input required by the supercritical tangentially fired boiler and the heat value of the coal. In addition, sufficient oxygen is required for the combustion of the supercritical tangentially fired boiler, and the oxygen is provided by the primary air and the secondary air during normal operation of the supercritical tangentially fired boiler, so when the flue gas of the gas turbine is introduced into the supercritical tangentially fired boiler, the oxygen contained in the flue gas of the gas turbine is also provided to the supercritical tangentially fired boiler to assist the combustion of coal, so in order to ensure the normal operation of the supercritical tangentially fired boiler under the condition of introducing the flue gas of the gas turbine, the amount of the primary air and the secondary air needs to be adjusted, but since the primary air not only provides oxygen for the combustion of the supercritical tangentially fired boiler, but also has the function of sending the coal required for combustion into the furnace, so under normal circumstances, the supercritical tangentially fired boiler can adapt to the introduction of the flue gas of the gas turbine mainly by adjusting the air flow of the secondary air, and the air flow of the primary air can be adjusted or slightly adjusted, and the relevant data of the primary air after slight adjustment are listed in the following Tables 1-1, 1-2 and 1-3, wherein the "primary air flow after introducing the flue gas of the gas turbine" refers to the primary air flow of the supercritical tangentially fired boiler after adjustment when the first flue gas amount of the gas turbine is introduced.

[0047] The above content will be explained and described by using three tables (i.e. Table 1-1, Table 1-2 and Table 1-3) as follows:

[0048] Table 1-1 is the primary air volume, the secondary air volume, the total coal volume and the exhaust gas volume (equal to the air preheater inlet flue gas flow) obtained by the supercritical tangential boiler (i.e. coal-fired boiler) under the rated load and the average load, wherein the primary air volume is the preset primary air volume when the gas turbine is coupled with the supercritical tangential boiler, the secondary air volume is the preset secondary air volume when the gas turbine is coupled with the supercritical tangential boiler, the total coal volume is the preset total coal volume when the gas turbine is coupled with the supercritical tangential boiler, and the exhaust gas volume is the preset boiler flue gas volume when the gas turbine is coupled with the supercritical tangential boiler, wherein the corresponding parameters of the gas turbine and the supercritical tangential boiler when coupled are shown in Table 1-3.

[0049] Table 1-2 mainly shows the flue gas volume (equal to the air exhaust flue gas flow) obtained by the gas turbine under the rated load and the average load, and the oxygen content in the flue gas and the enthalpy change value of the flue gas within a certain period of time, wherein the flue gas volume will be the first gas turbine flue gas volume when the gas turbine is coupled with the supercritical tangential boiler, and this will be seen in Table 1-3 which shows the corresponding parameters of the gas turbine and the supercritical tangential boiler when coupled.

[0050] Table 1-3 shows that the gas turbine and the supercritical tangential boiler can still maintain normal operation under the condition that the flue gas of the gas turbine is introduced into the supercritical tangential boiler, i.e. the gas turbine is coupled with the supercritical tangential boiler, and the parameters can be obtained according to the contents in Table 1-1 and Table 1-2.

[0051] It should be noted that in Table 1-3, under the condition of the first gas turbine flue gas volume introduced by the gas turbine, the ratio of the first boiler flue gas volume generated by the supercritical tangential boiler to the preset boiler flue gas volume is 3.9% under the rated load and 5.3% under the average load, both of which are less than the preset ratio threshold of 10%, so in Table 1-3, the target gas turbine flue gas volume is the first gas turbine flue gas volume, the second coal volume is the first coal volume, and the second secondary air volume is the first secondary air volume.

[0052] Table 1-1. Parameter table of supercritical tangential boiler under different loads:

[0053]

[0054]

[0055] Table 1-2. Parameter table of gas turbine under different loads:

[0056]

[0057] Table 1-3. Parameter table of gas turbine and supercritical tangential boiler coupling under different loads:

[0058]

[0059] The preferred embodiments of the present disclosure are described in detail above with reference to the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0060] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0061] In addition, various different embodiments of the present disclosure can also be combined in any appropriate manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A method for coupling gas turbine exhaust gas with air distribution from a coal-fired boiler, characterized in that, The method comprises the following steps: According to the first gas turbine flue gas amount introduced into the secondary air duct of the coal-fired boiler, determining the actual required first secondary air amount and the first coal-burning amount of the coal-fired boiler; According to the first gas turbine flue gas amount, the preset primary air amount and the preset total oxygen amount, determining the actual required first secondary air amount of the coal-fired boiler; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler under the operating load; according to the change value of the enthalpy value of the first gas turbine flue gas amount within a preset time period, the calorific value of the coal quality required by the coal-fired boiler and the preset total coal amount, determining the actual required first coal-burning amount of the coal-fired boiler; the preset total coal amount is the total coal amount required by the coal-fired boiler under the operating load; According to the first gas turbine flue gas amount, the preset primary air amount, the first secondary air amount and the first coal-burning amount, determining the first boiler flue gas amount actually discharged by the coal-fired boiler; the preset primary air amount is the primary air amount required by the coal-fired boiler under the operating load; According to the first boiler flue gas amount and the preset boiler flue gas amount, determining the target gas turbine flue gas amount actually introduced into the coal-fired boiler by the gas turbine; the preset boiler flue gas amount is the flue gas amount generated by the coal-fired boiler under the operating load.

2. The method of claim 1, wherein the gas turbine exhaust is coupled to the air supply of the coal-fired boiler. The method comprises the following steps: According to the first gas turbine flue gas amount, the preset primary air amount and the preset total oxygen amount, determining the actual required first secondary air amount of the coal-fired boiler; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler under the operating load; according to the change value of the enthalpy value of the first gas turbine flue gas amount within a preset time period, the calorific value of the coal quality required by the coal-fired boiler and the preset total coal amount, determining the actual required first coal-burning amount of the coal-fired boiler; the preset total coal amount is the total coal amount required by the coal-fired boiler under the operating load; According to the first gas turbine flue gas amount, the preset primary air amount and the preset total oxygen amount, determining the actual required first secondary air amount of the coal-fired boiler; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler under the operating load; according to the change value of the enthalpy value of the first gas turbine flue gas amount within a preset time period, the calorific value of the coal quality required by the coal-fired boiler and the preset total coal amount, determining the actual required first coal-burning amount of the coal-fired boiler; the preset total coal amount is the total coal amount required by the coal-fired boiler under the operating load; According to the first gas turbine flue gas amount, the preset primary air amount, the first secondary air amount and the first coal-burning amount, determining the first boiler flue gas amount actually discharged by the coal-fired boiler; the preset primary air amount is the primary air amount required by the coal-fired boiler under the operating load; According to the first boiler flue gas amount and the preset boiler flue gas amount, determining the target gas turbine flue gas amount actually introduced into the coal-fired boiler by the gas turbine; the preset boiler flue gas amount is the flue gas amount generated by the coal-fired boiler under the operating load.

3. The method of claim 1, wherein the method further comprises: The method comprises the following steps: According to the first gas turbine flue gas amount, the preset primary air amount and the preset total oxygen amount, determining the actual required first secondary air amount of the coal-fired boiler; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler under the operating load; according to the change value of the enthalpy value of the first gas turbine flue gas amount within a preset time period, the calorific value of the coal quality required by the coal-fired boiler and the preset total coal amount, determining the actual required first coal-burning amount of the coal-fired boiler; the preset total coal amount is the total coal amount required by the coal-fired boiler under the operating load; According to the first gas turbine flue gas amount, the preset primary air amount and the preset total oxygen amount, determining the actual required first secondary air amount of the coal-fired boiler; the preset total oxygen amount is the total oxygen amount required by the coal-fired boiler under the operating load; according to the change value of the enthalpy value of the first gas turbine flue gas amount within a preset time period, the calorific value of the coal quality required by the coal-fired boiler and the preset total coal amount, determining the actual required first coal-burning amount of the coal-fired boiler; the preset total coal amount is the total coal amount required by the coal-fired boiler under the operating load; 4. The method of claim 1, wherein the method further comprises: The determining the target flue gas amount of the gas turbine actually introduced into the coal-fired boiler according to the first boiler flue gas amount and the preset boiler flue gas amount comprises: In the case that the first boiler flue gas amount actually discharged by the coal-fired boiler is greater than or equal to a preset proportion threshold of the preset boiler flue gas amount, reducing the first flue gas amount of the gas turbine introduced into the secondary air duct of the coal-fired boiler; and cyclically executing the flue gas amount adjusting step until a preset termination condition is met; The flue gas amount adjusting step comprises: determining the second secondary air amount and the second coal-burning amount actually required by the coal-fired boiler according to the first flue gas amount of the gas turbine introduced into the secondary air duct of the coal-fired boiler; determining the second boiler flue gas amount actually discharged by the coal-fired boiler according to the first flue gas amount, the preset primary air amount, the second secondary air amount and the second coal-burning amount; determining the second flue gas amount of the gas turbine actually introduced into the coal-fired boiler according to the second boiler flue gas amount and the preset boiler flue gas amount; and taking the second flue gas amount as the new first flue gas amount of the gas turbine. The preset termination condition is that the first boiler flue gas amount actually discharged by the coal-fired boiler is less than a preset proportion threshold of the preset boiler flue gas amount.

5. A system for coupling flue gas from a gas turbine with air for a coal-fired boiler, adapted for use in a method for coupling flue gas from a gas turbine with air for a coal-fired boiler according to any one of claims 1 to 4, characterized in that, Comprise: An exhaust flue for communicating with a secondary air duct of a coal-fired boiler to pass flue gas discharged by a gas turbine into the secondary air duct of the coal-fired boiler and mix with secondary air in the secondary air duct to obtain mixed secondary air; And A secondary air adjusting device for being arranged at a nozzle of the secondary air duct to adjust the air amount of the mixed secondary air injected into a hearth of the coal-fired boiler, The system that the flue gas of the gas turbine is coupled with air distribution of the coal-fired boiler further comprises an exhaust air fan, and the exhaust flue is used for communicating with the gas turbine through the exhaust air fan.

6. The system for coupling a gas turbine exhaust with a coal-fired boiler air supply according to claim 5, wherein, The secondary air adjusting device comprises a secondary air box and an air port adjusting assembly, the secondary air box is through in the length direction to form a jet channel, one end of the jet channel is used for communicating with the secondary air duct, and the other end is used for passing into the hearth, and the air port adjusting assembly is slidably arranged on the secondary air box to adjust the cross-sectional size of the jet channel.

7. The system for coupling a gas turbine exhaust with a coal-fired boiler according to claim 6, wherein, The air port adjusting assembly comprises a partition plate and an air port adjusting plate, the partition plate extends along the length direction of the jet channel to separate the jet channel into an air inlet channel and an adjusting channel, the air port adjusting plate is fixedly arranged at one end of the partition plate and blocks the adjusting channel, an adjusting pull rod is fixedly arranged on the air port adjusting plate, and the adjusting pull rod drives the air port adjusting plate and the partition plate to reciprocate along a direction perpendicular to the jet channel to adjust the size of the air inlet channel and the adjusting channel.

8. The system of claim 5, wherein, The exhaust flue comprises an exhaust flue main pipe and a plurality of The exhaust gas total pipeline is used for communicating with an exhaust gas outlet of the gas turbine, and the exhaust gas sub-pipelines are respectively used for communicating with the secondary air ducts of the coal-fired boiler, so that the exhaust gas of the gas turbine is respectively correspondingly introduced into the secondary air ducts of the coal-fired boiler through the exhaust gas total pipeline and the exhaust gas sub-pipelines, and is mixed with the secondary air in the secondary air ducts to obtain mixed secondary air.

9. The system for coupling a gas turbine exhaust with a coal-fired boiler according to claim 8, wherein, The system for coupling the exhaust gas of the gas turbine with the air distribution of the coal-fired boiler further comprises an exhaust gas mixing device, the exhaust gas sub-pipeline comprises a smoke feeding section arranged in the secondary air duct, and the exhaust gas mixing device is configured as a plurality of smoke feeding through holes formed in a pipe wall of the smoke feeding section.

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