CN108954318B - Analysis system and analysis method for axial staged premixed combustion characteristics of gas fuel - Google Patents

Abstract

The invention discloses an analysis system and analysis method for the axial staged premixed combustion characteristics of gaseous fuels. By using the analysis system for the axially staged premixed combustion characteristics of gaseous fuels in the present invention, the pollutant content under different working condition parameters can be obtained , the main combustion flame image and the secondary combustion flame image, so as to obtain the axially graded premixed combustion characteristics. Therefore, there is no need for on-site verification, which reduces the research cost of axially staged premixed combustion. In addition, the analysis system for the axial staged premixed combustion characteristics of the gaseous fuel in the present invention can also analyze different fuels, and has a wide range of applications. The analysis system in the present invention is used for analyzing the axial staged premixed combustion characteristics of the gaseous fuel.

Description

Analysis system and method for axially staged premixed combustion characteristics of gaseous fuel

technical field

The invention relates to the technical field of fuel combustion characteristic analysis, and more specifically, relates to an analysis system and analysis method for gas fuel axially staged premixed combustion characteristics.

Background technique

Axial staged combustion technology has been widely applied to gas turbines. It has been verified on the spot that it has a remarkable effect in adjusting the load range and reducing emissions. At the same time, it can be found from the structure of the gas turbine combustor that currently applies axial staged technology that the manufacturer's blending of axial staged Sexual focus and determination of optimum secondary fuel/air distribution ratios and residence times have a large impact on axially staged combustion characteristics. However, the research on the axially staged combustion characteristics can only be carried out on site, and the research cost is high.

Therefore, how to reduce the research cost of axially staged premixed combustion has become an urgent technical problem to be solved by those skilled in the art.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is how to reduce the research cost of axially staged premixed combustion. Therefore, the present invention provides an analysis system and analysis method for gaseous fuel axially staged premixed combustion characteristics.

To achieve the above object, the present invention provides the following technical solutions:

An analysis system for axially staged premixed combustion characteristics of gaseous fuels, including:

a fuel inlet for the introduction of gaseous fuel;

Air inlet for introducing air;

an axially staged burner having a primary combustion zone and a secondary combustion zone;

a primary fuel supply conduit in communication with the primary injection assembly of the primary combustion zone;

a secondary fuel supply tube in communication with the secondary injection assembly of the secondary combustion zone;

A fuel distributor that communicates with the fuel inlet port and the primary fuel supply pipe and the secondary fuel supply pipe, and the fuel distributor can adjust the primary fuel flow rate and the flow rate of the primary fuel entering the primary fuel supply pipe. the secondary fuel flow rate of the secondary fuel supply pipe;

a primary air supply duct communicating with the air inlet of said primary combustion zone;

a secondary air supply pipe communicating with said secondary fuel supply pipe;

An air distributor that communicates with the air inlet port and the primary air supply pipe and the secondary air supply pipe, and the air distributor can adjust the primary air flow rate and the entry into the primary air supply pipe the secondary air flow rate of the secondary air supply pipe;

A flue gas detector for detecting the pollutant content in the flue gas discharged from the axially staged burner;

a flame acquisition instrument for collecting a primary combustion flame image of the primary combustion zone and a secondary combustion flame image of the secondary combustion zone; and

The controller receives working condition parameters, and controls the air distributor and the fuel distributor according to the working condition parameters to adjust the primary air flow rate, the secondary air flow rate, and the primary fuel flow rate and the secondary fuel flow rate are within the corresponding threshold; and the corresponding pollutant content, main combustion flame image and secondary combustion flame image under the working condition parameters are obtained.

Preferably, in the above analysis system for axially staged premixed combustion characteristics of gaseous fuel, the working condition parameters include: total equivalence ratio, secondary equivalence ratio and secondary load ratio.

Preferably, in the above-mentioned analysis system for axially staged premixed combustion characteristics of gaseous fuel, the secondary injection assembly includes four nozzles, and the operating condition parameters also include the number of openings of the nozzles, and the secondary injection assembly according to the The operating parameters described above determine the opening or closing of the nozzle.

Preferably, in the above-mentioned analysis system for axially staged premixed combustion characteristics of gaseous fuels, the diameter of the nozzles is 1mm or 2mm, and four nozzles are arranged crosswise.

Preferably, in the above-mentioned analysis system for axially staged premixed combustion characteristics of gaseous fuel, the fuel distributor includes a first mass flow controller arranged on the first-stage fuel supply pipe and a first mass flow controller arranged on the second-stage fuel supply pipe. The second mass flow controller on the supply pipe, wherein the range of the first mass flow controller is 0-200SLM, and the range of the second mass flow controller is 0-5SLM.

Preferably, in the above-mentioned analysis system of gaseous fuel axially staged premixed combustion characteristics, the fuel distributor further includes a third mass flow controller arranged in parallel with the first mass flow controller, wherein the The range of the third mass flow control is 0-37.5SLM.

Preferably, in the above-mentioned analysis system of gaseous fuel axially staged premixed combustion characteristics, the air distributor includes a fourth mass flow controller arranged on the primary air supply pipe and a fourth mass flow controller arranged on the secondary air supply pipe. The fifth mass flow controller on the supply pipe, wherein the fourth mass flow controller has a range of 0-1000SLM, and the fifth mass flow controller has a range of 0-50SLM.

Preferably, in the above-mentioned analysis system for axial staged premixed combustion characteristics of gaseous fuel, the fuel inlet end is further provided with a first switching valve, and the primary fuel supply pipe is provided with a second switching valve, and the two The stage fuel supply pipe is provided with a third switch valve, and the air inlet end is further provided with a fourth switch valve.

The present invention also discloses an analysis method for the axial staged premixed combustion characteristics of gaseous fuel, including:

Dock the fuel with the fuel inlet;

Connect the air to the air inlet port;

Set working condition parameters;

receiving operating condition parameters, and controlling the air distributor and the fuel distributor according to the operating condition parameters to adjust the primary air flow rate, the secondary air flow rate, the primary fuel flow rate and the The secondary fuel flow rate is within the corresponding threshold; and the corresponding pollutant content, main combustion flame image and secondary combustion flame image under the working condition parameters are obtained.

Preferably, in the above analysis method of gaseous fuel axially staged premixed combustion characteristics, the pollutant content includes NO _X content and CO content.

It can be seen from the above-mentioned technical scheme that by adopting the analysis system of gaseous fuel axial staged premixed combustion characteristics in the present invention, the pollutant content, main combustion flame image and secondary combustion flame image under different working conditions parameters can be obtained, thereby Axial staged premixed combustion characteristics are obtained. Therefore, no field verification is required, which reduces the research cost of axially staged premixed combustion. In addition, the analysis system for the axial staged premixed combustion characteristics of gaseous fuels in the present invention can also analyze different fuels, and has a wide range of applications.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of an analysis system for the axially staged premixed combustion characteristics of a gaseous fuel provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of another analysis system for axially staged premixed combustion characteristics of gaseous fuel provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of another analysis system for axially staged premixed combustion characteristics of gaseous fuel provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of another analysis system for axially staged premixed combustion characteristics of gaseous fuel provided by an embodiment of the present invention;

Fig. 5 is a schematic diagram of another analysis system for axially staged premixed combustion characteristics of gaseous fuel provided by an embodiment of the present invention;

In the figure, 101 is the fuel inlet, 102 is the primary fuel supply pipe, 103 is the secondary fuel supply pipe, 104 is the air inlet, 105 is the primary air supply pipe, 106 is the secondary air supply pipe, 200 300 is the fuel distributor, 301 is the first mass flow controller, 302 is the second mass flow controller, 303 is the third mass flow controller, 400 is the air distributor, 401 is the fourth Mass flow controller, 402 is the fifth mass flow controller, 500 is the smoke detector, 600 is the flame collector, 700 is the controller, 801 is the first switching valve, 802 is the second switching valve, 803 is the third On-off valve, 804 is the fourth on-off valve.

Detailed ways

The core of the present invention is to provide an analysis system and analysis method for gaseous fuel axially staged premixed combustion characteristics, so as to reduce the research cost of axially staged premixed combustion.

In addition, the examples shown below do not limit the content of the invention described in the claims in any way. In addition, all the contents of the configurations shown in the following embodiments are not limited to be essential to the solution of the invention described in the claims.

Please refer to Fig. 1 to Fig. 5, the analysis system of gaseous fuel axially staged premixed combustion characteristic in the present invention, comprises: fuel inlet port 101, air inlet port 104, axially staged combustor 200, primary fuel supply Pipe 102, secondary fuel supply pipe 103, fuel distributor 300, primary air supply pipe 105, secondary air supply pipe 106, air distributor 400, smoke detector 500, flame collector 600 and controller 700. in:

The fuel inlet 101 is used to introduce gaseous fuel, and the fuel is directly connected to the fuel inlet 101 to provide fuel to the entire system;

The air inlet 104 is used to introduce air, and the air is directly connected to the air inlet 104 to provide air for the whole system;

Axially graded burner 200, with a main combustion zone and a secondary combustion zone; the main combustion zone and the secondary combustion zone use quartz glass tubes with a length of 300mm respectively, wherein the burner in the main combustion zone adopts lean premixed combustion, and the secondary combustion zone Also take premixed combustion. The injection assembly of the secondary combustion zone includes four nozzles that can be controlled and closed separately. The diameter of the secondary nozzles is 1 mm or 2 mm, and the arrangement is cross arrangement.

The primary fuel supply pipe 102 communicates with the primary injection assembly of the main combustion zone, and is used to introduce fuel into the primary injection assembly of the main combustion zone for combustion in the primary combustion zone;

The secondary fuel supply pipe 103 communicates with the secondary injection assembly of the secondary combustion zone, and is used to introduce fuel into the secondary injection assembly of the secondary combustion zone to burn in the secondary combustion zone; in the embodiment of the present invention , the secondary fuel supply pipe 103 is a rubber pipe, and the length of the pipe is relatively long, and the secondary fuel/air premixed gas has reached a state of uniform mixing before being injected into the secondary combustion zone.

The fuel distributor 300 is connected to the fuel inlet port 101 and the primary fuel supply pipe 102 and the secondary fuel supply pipe 103. The fuel distributor 300 can regulate the primary fuel flow rate entering the primary fuel supply pipe 102 and the secondary fuel supply pipe. The secondary fuel flow rate of the pipe 103; there are many structures that can realize the fuel distribution of the primary fuel supply pipe 102 and the secondary fuel supply pipe 103, and the present invention will not focus on the description. In order to achieve precise control, in the embodiment of the present invention Further, the fuel distributor 300 includes a first mass flow controller 301 disposed on the primary fuel supply pipe 102 and a second mass flow controller 302 disposed on the secondary fuel supply pipe 103, wherein the first mass flow The range of the controller 301 is 0-200SLM, and its accuracy is 1% of full scale, and the range of the second mass flow controller 302 is 0-5SLM.

In addition, in order to adapt to different working conditions, the fuel distributor 300 also includes a third mass flow controller 303 arranged in parallel with the first mass flow controller 301 , wherein the range of the third mass flow control is 0-37.5SLM. When the working condition parameter exceeds the range of the second mass flow controller 302 , the controller selects the third mass flow controller 303 to adjust the flow distributed to the secondary fuel supply pipe 103 .

The primary air supply pipe 105 communicates with the air inlet of the main combustion zone and is used to provide air to the main combustion zone;

The secondary air supply pipe 106 communicates with the secondary fuel supply pipe 103 and is used for premixing with the fuel in the secondary fuel supply pipe 103; within the scope of protection of the invention. In the embodiment of the present invention, the secondary air supply pipe 106 is a rubber pipe, and the length of the pipe is relatively long, so that the air and fuel can be mixed evenly before entering the secondary injection assembly of the secondary combustion zone;

The air distributor 400 is connected to the air inlet port 104 and the primary air supply pipe 105 and the secondary air supply pipe 106. The air distributor 400 can adjust the primary air flow entering the primary air supply pipe 105 and the secondary air supply Tube 106 for secondary air flow. There are many structures capable of distributing air to different pipes, which are not specifically described in the present invention, and in order to achieve precise control, the air distributor 400 in the embodiment of the present invention includes a fourth mass arranged on the primary air supply pipe 105 The flow controller 401 and the fifth mass flow controller 402 arranged on the secondary air supply pipe 106, wherein the fourth mass flow controller 401 has a range of 0-1000 SLM, and the fifth mass flow controller 402 has a range of 0 -50SLM.

The smoke detector 500 is used to detect the pollutant content in the smoke exhausted by the axially staged burner 200 . Normally, the flue gas detector 500 includes a flue gas sampling probe and a flue gas analyzer, wherein the sampling probe is used to sample the flue gas, and the flue gas analyzer is used to analyze the _O2 , CO, NO and NO ₂ content, in the embodiment of the present invention, the sampling probe is set at the outlet of the secondary combustion zone, the sampling hole is facing the direction of the flue gas flow, the sampling probe introduces the flue gas into the flue gas analyzer, and analyzes the flue gas. The content of O ₂ , CO, NO and NO ₂ in the air, the measurement accuracy of O ₂ is ±0.2%, and the measurement accuracy of CO, NO and NO ₂ is ±5% of the measured value. When actually measuring the flue gas composition, the flue gas composition data is calculated within a period of time after the flue gas composition is stable, and the arithmetic mean is obtained to obtain the flue gas composition under this working condition. The NO _x /CO emission data have been converted to The state of dry oxygen concentration 15% (@15%O2).

The flame collecting instrument 600 is used to collect the main combustion flame image of the main combustion zone and the secondary combustion flame image of the secondary combustion zone. In order to obtain the heat release intensity of the flame under different combustion conditions, the distribution of OH* (OH chemical autofluorescence) was obtained by testing, indicating the position of the main reaction zone. The stronger the OH* signal, the higher the local heat release rate. OH *Weaker signal indicates lower heat release rate. The OH* test is obtained by ICCD (enhanced CCD) camera combined with BP308/10 narrow-band filter. The ICCD shutter speed is set to 600000ns, and the delay time value is 5ns to ensure that the measurement is carried out within the pulse width of each pulse, which can accurately capture the flame shape , and reduce clutter interference. The image is processed by methods such as average (Average, AVG) and root mean square (Root Mean Square, RMS) after background noise correction.

The controller 700 receives the working condition parameters, and controls the air distributor 400 and the fuel distributor 300 according to the working condition parameters to adjust the primary air flow, secondary air flow, primary fuel flow and secondary fuel flow at corresponding thresholds and obtain the corresponding pollutant content, main combustion flame image and secondary combustion flame image under the working condition parameters. The above working condition parameters include: total equivalence ratio, secondary equivalence ratio and secondary load ratio; pollutant content includes: NO _X content and CO content.

By adopting the analysis system for the axial staged premixed combustion characteristics of the gas fuel in the present invention, the pollutant content, the main combustion flame image and the secondary combustion flame image under different operating conditions can be obtained, thereby obtaining the axial staged premixed combustion characteristics. Therefore, no field verification is required, which reduces the research cost of axially staged premixed combustion. In addition, the analysis system for the axial staged premixed combustion characteristics of gaseous fuels in the present invention can also analyze different fuels, and has a wide range of applications. The analysis system in the present invention is used for analyzing the axial staged premixed combustion characteristics of the gaseous fuel.

In order to further expand the scope of application of the analysis system, the secondary injection assembly in the secondary combustion zone of the present invention includes four nozzles, and the operating condition parameters also include the number of openings of the nozzles, and the secondary injection assembly determines the opening of the nozzles according to the operating condition parameters or off. The diameter of the nozzle is 1mm or 2mm, and four nozzles are arranged crosswise.

The following natural gas is replaced by 99.9% methane fuel, and the temperature of fuel and air inlet is normal temperature:

Based on the fuel axial classification and the Chemkin zero-dimensional analysis and simulation results for different equivalence ratios of the secondary premixed gas, it is found that increasing the equivalence ratio of the secondary stage is beneficial to reducing NOx emissions. Proportional experimental research, considering that the length of the secondary flame should not be too long, the secondary nozzle structure arrangement when the secondary equivalent ratio is 5 is 2 secondary nozzles with a diameter of 2mm. The ratio of secondary load is changed to 5% and 10%. For the same ratio of secondary load, the combustion characteristics at different adiabatic flame temperatures are studied by changing the total equivalent ratio. When the secondary load ratio is 5%, the secondary fuel flow rate is small. The second mass flow controller 302 is controlled by Bronkhorst thermal mass flowmeter/controller with high precision, its precision is ±0.8% of reading +±0.2% of full scale, and the range is 0-5SLM; when the fuel secondary load is 10 %, the third mass flow controller 303 adopts a thermal mass flowmeter with a range of 0-50SLM, and its accuracy is 1% of full scale;

In order to use the Bronkhorst thermal mass flowmeter with high precision to control the fuel secondary load ratio unchanged, considering that when the secondary load ratio is large, it will exceed the Bronkhorst range, therefore, when the secondary load ratio is 5%, different secondary load ratios are selected. Experimental study on equivalence ratio of premixed gas. The second-stage equivalence ratio is divided into two cases: lean burn and rich burn. At the same time, in order to avoid the influence of different adiabatic flame temperatures of the second-stage premixed gas on the NOx/CO emission of fuel axially staged combustion, two cases with the same adiabatic flame temperature near equivalence ratio 1 are selected. Equivalence ratios are studied, which are 0.8 and 1.25, respectively. The NOx/CO emissions of the same fuel secondary load ratio and secondary equivalence ratio were measured at different flame temperatures by changing the total equivalence ratio.

Also considering the accuracy of secondary fuel measurement, the research of different fuel staged injection structures is carried out when the secondary load ratio is 5%. Different fuel staged injection structures are divided into two-stage injection methods and two-stage nozzle diameters. The two-stage injection methods are 4 nozzles intersecting jets and 2 nozzles facing each other. The diameters of the secondary nozzles are 1mm and 2mm respectively.

The research on the influence of fuel axial staged combustion characteristics mainly investigates the flame structure and pollutant emissions, focusing on pollutant emissions, and compares the advantages of axial fuel staged combustion with traditional lean premixed combustion.

Table 1: Corresponding table of parameters for different working conditions of fuel axially staged combustion

Under the action of the above-mentioned analysis system, the pollutant content under different working conditions is finally obtained, as shown in Table 2:

Table 2: Pollutant content table corresponding to different working condition parameters of fuel axially staged combustion

In order to facilitate control, the fuel inlet end is also provided with a first on-off valve 801, the primary fuel supply pipe is provided with a second on-off valve 802, the secondary fuel supply pipe is provided with a third on-off valve 803, and the air inlet end is also provided with a The fourth switch valve 804 . By arranging the first on-off valve 801, it is possible to control the cut-off section of the fuel introduction at the fuel inlet; by arranging the second on-off valve 802, it is possible to directly control the on-off of the fuel introduction on the primary fuel supply pipe; by setting the third switch The valve 803 can directly control the opening and closing of fuel introduction on the secondary fuel supply pipe. By setting the fourth on-off valve 804, it is possible to directly control the opening and closing of the air introduced into the air inlet port.

The present invention also discloses an analysis method for the axial staged premixed combustion characteristics of gaseous fuel, including:

Dock the fuel with the fuel inlet;

Connect the air to the air inlet port;

Set working condition parameters; in the present invention, working condition parameters can be set according to experience to obtain more favorable experimental data.

receiving operating condition parameters, and controlling the air distributor and the fuel distributor according to the operating condition parameters to adjust the primary air flow rate, the secondary air flow rate, the primary fuel flow rate and the The secondary fuel flow rate is within the corresponding threshold; and the corresponding pollutant content, main combustion flame image and secondary combustion flame image under the working condition parameters are obtained.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. An analysis system for the axially staged premixed combustion characteristics of a gaseous fuel, comprising:

a fuel inlet for introducing gaseous fuel;

an air inlet for introducing air;

an axial staged combustor having a primary combustion zone and a secondary combustion zone;

a primary fuel supply pipe in communication with the primary injection assembly of the primary combustion zone;

a secondary fuel supply pipe in communication with the secondary injection assembly of the secondary combustion zone; the fuel access end is also provided with a first switch valve, the primary fuel supply pipe is provided with a second switch valve, the secondary fuel supply pipe is provided with a third switch valve, and the air access end is also provided with a fourth switch valve;

a fuel distributor communicating the fuel access end with the primary and secondary fuel supply pipes, the fuel distributor being capable of regulating a primary fuel flow rate into the primary fuel supply pipe and a secondary fuel flow rate into the secondary fuel supply pipe;

a primary air supply duct in communication with the air inlet of the primary combustion zone;

a secondary air supply pipe in communication with the secondary fuel supply pipe;

an air distributor communicating the air inlet with the primary air supply pipe and the secondary air supply pipe, the air distributor being capable of regulating a primary air flow rate into the primary air supply pipe and a secondary air flow rate into the secondary air supply pipe;

a flue gas detector for detecting the content of pollutants in the flue gas discharged by the axial staged burner;

the flame acquisition instrument is used for acquiring a main combustion flame image of the main combustion zone and a secondary combustion flame image of the secondary combustion zone; and

the controller is used for receiving working condition parameters, and controlling the air distributor and the fuel distributor according to the working condition parameters so as to adjust the primary air flow rate, the secondary air flow rate, the primary fuel flow rate and the secondary fuel flow rate to be within corresponding thresholds; the corresponding pollutant content, the main combustion flame image and the secondary combustion flame image under the working condition parameters are obtained; the working condition parameters comprise: total equivalence ratio, secondary equivalence ratio, and secondary load ratio.

2. The system for analyzing the axial staged premixed combustion characteristics of gaseous fuel of claim 1, wherein said secondary injection assembly comprises four nozzles, said operating parameters further comprise the number of nozzles open, and said secondary injection assembly determines whether a nozzle is open or closed based on said operating parameters.

3. The system for analyzing the axial staged premixed combustion characteristics of gaseous fuel according to claim 2, wherein said nozzles have a diameter of 1mm or 2mm, four of said nozzles being arranged crosswise.

4. The system for analyzing the axially staged premixed combustion characteristics of gaseous fuel of claim 3, wherein said fuel dispenser comprises a first mass flow controller disposed on said primary fuel supply pipe and a second mass flow controller disposed on said secondary fuel supply pipe, wherein said first mass flow controller has a range of 0 to 200SLM and said second mass flow controller has a range of 0 to 5SLM.

5. The system for analyzing axially staged premixed combustion characteristics of gaseous fuel of claim 4, wherein said fuel dispenser further comprises a third mass flow controller disposed in parallel with said first mass flow controller, wherein said third mass flow controller has a range of 0-37.5SLM.

6. The system for analyzing axially staged premixed combustion characteristics of gaseous fuel of claim 5, wherein said air distributor comprises a fourth mass flow controller disposed on said primary air supply pipe and a fifth mass flow controller disposed on said secondary air supply pipe, wherein said fourth mass flow controller has a range of 0-1000SLM and said fifth mass flow controller has a range of 0-50SLM.