Control system and control method for flameless burner

Abstract

The present invention discloses a control system and a control method for a flameless burner. The system includes: a preheater for preheating fuel and air; a fuel component detection module for detecting the component information of the fuel; a flue gas concentration detection module for detecting the oxygen content concentration and the nitride concentration of the flue gas; a temperature detection module for detecting the temperature information of the combustion chamber and the temperature of the flameless combustion zone at the tail of the combustion chamber; a control module for analyzing the calorific value of the fuel according to the component information of the fuel and obtaining control information based on the detected temperature information and the oxygen content concentration of the flue gas; and a gas mass flow controller for controlling the mass and flow rate of the output gas in the channel according to the control information. The present invention detects the component information of the fuel at the source of the pyrolysis gas, calculates the calorific value of the fuel, obtains the fuel flow rate under a specified heat load, realizes the effect of wide calorific value, meets the conditions of different fuel components, and can be widely applied to the technical field of fuel burners.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel burners, and in particular to a control system and a control method for a flameless burner. Background Art

[0002] Gas combustion methods include diffusion combustion and premixed combustion, both of which are flame combustions. The fatal drawback of flame combustion is the oxidation reaction of combustible substances under the participation of free radicals, which releases energy in the form of visible light, resulting in low energy utilization efficiency; in addition, nitrogen in the air participates in the combustion reaction to form toxic pollutants NOx, and the low combustion efficiency generates considerable unburned HC and CO, which will cause environmental pollution when discharged into the atmosphere. Flameless combustion is one of the effective ways to solve the problems of incomplete combustion of gas fuels, low thermal efficiency, high CO emission concentration, etc. However, traditional flameless burners mainly solve the problems of inefficient and high-emission combustion through catalysis, or are designed for fuels within a certain calorific value range, or increase the air preheater for preheating to improve the combustion efficiency, etc. Such burners have a narrow fuel application range and a single application field, and are not suitable for the combustion requirements of pyrolysis gas with complex components of municipal solid waste, stale waste and industrial solid waste. There are potential safety hazards such as unstable combustion and incomplete combustion. Summary of the Invention

[0003] To solve at least one of the technical problems existing in the prior art to a certain extent, the purpose of the present invention is to provide a control system and a control method for a flameless burner.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A control system for a flameless burner, comprising:

[0006] A preheater for preheating fuel and air;

[0007] A fuel component detection module, arranged at the front end of the preheater, for detecting the component information of the fuel;

[0008] A flue gas concentration detection module, arranged at the end of the burner, for detecting the oxygen content concentration and nitride concentration of the flue gas;

[0009] A temperature detection module, arranged in the middle of the burner, for detecting the temperature information of the combustion chamber and the temperature of the flameless combustion zone at the tail of the combustion chamber;

[0010] A control module for analyzing the calorific value of the fuel according to the component information of the fuel, obtaining control information according to the detected temperature information and the oxygen content concentration of the flue gas, and controlling the working state of the preheater;

[0011] A gas mass flow controller is provided on the fuel channel and the air channel to control the mass and flow rate of the output gas in the channels according to control information.

[0012] Further, the control system further includes:

[0013] An air ejector is provided at the end of the air channel to eject air according to a preset angle and jet velocity;

[0014] A fuel ejector is provided at the end of the fuel channel to eject fuel according to a preset angle and jet velocity.

[0015] Further, the size of the head nozzle of the ejector is adjustable, and the head nozzle can rotate axially.

[0016] Further, the head nozzle is a conical nozzle with a straight pipe, and the inner diameter of the conical nozzle is less than or equal to one fifth of the inner diameter of the straight pipe.

[0017] Further, the jet velocity range of the fuel is 10 - 30 m / s, and the jet velocity range of the air is 100 - 200 m / s.

[0018] Further, the temperature range of the combustion chamber is 1000°C - 1400°C.

[0019] Further, the fuel components include H2, CH4, C2, and CO.

[0020] Another technical solution adopted by the present invention is:

[0021] A control method for a flameless burner, comprising the following steps:

[0022] Obtain the fuel calorific value according to the component information of the fuel;

[0023] If the fuel calorific value is between 4000 - 10000 kJ / m 3 , start the preheater, and control the mass and flow rate of the fuel and air according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas;

[0024] If the fuel calorific value is between 10000 - 20000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas;

[0025] If the fuel calorific value is above 20000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber.

[0026] The beneficial effects of the present invention are as follows: The present invention detects the component information of the fuel at the source of the pyrolysis gas, calculates the calorific value of the fuel, and obtains the fuel flow rate under a specified heat load, achieving the effect of a wide calorific value (i.e., large fluctuations in the fuel calorific value) and meeting the conditions of different fuel components. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following introduces the related technical solution drawings in the embodiments of the present invention or the prior art. It should be understood that the drawings below only conveniently and clearly show some embodiments of the technical solutions in the present invention. For those skilled in the art, without creative work, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is a cross-sectional view of a control system of a flameless burner in an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of a method of a flameless burner in an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of the central cross-section temperature distribution under different excess air coefficients in an embodiment of the present invention;

[0031] Figure 4 is a schematic diagram of the central cross-section temperature distribution under different air inlet cross-sectional areas in an embodiment of the present invention;

[0032] Figure 5 is a flowchart of the steps of a control method of a flameless burner in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following details the embodiments of the present invention. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention. For the step numbers in the following embodiments, they are only set for the convenience of elaboration and explanation, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0034] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0035] In the description of the present invention, the meaning of "several" is one or more, the meaning of "multiple" is more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the base number, and understandings such as "above", "below", "within", etc. include the base number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0037] This embodiment provides a control system for a flameless burner, including:

[0038] A preheater for preheating fuel and air;

[0039] A fuel component detection module is arranged at the front end of the preheater for detecting the component information of the fuel;

[0040] A flue gas concentration detection module is arranged at the end of the burner for detecting the oxygen content concentration and nitride concentration of the flue gas;

[0041] A temperature detection module is arranged in the middle of the burner for detecting the temperature information of the combustion chamber and the temperature of the flameless combustion zone at the tail of the combustion chamber;

[0042] A control module is used for analyzing the calorific value of the fuel according to the component information of the fuel, obtaining control information according to the detected temperature information and the oxygen content concentration of the flue gas, and controlling the working state of the preheater;

[0043] A gas mass flow controller is arranged on the fuel channel and the air channel for controlling the mass and flow of the output gas in the channel according to the control information.

[0044] This embodiment provides a control system for a flameless burner with a wide calorific value. By combining the characteristics of the calorific value of the fuel itself, key components such as H2 and CH4 that affect the calorific value are analyzed and evaluated. Accordingly, flameless combustion with different interval calorific values can be realized. When the calorific value is too large, the input amount of the fuel can be reduced; when the calorific value is too small, the input amount of the fuel can be increased. And it can effectively solve the problem of generating a large amount of nitrogen oxides during the fuel combustion process, and can effectively achieve wide-calorific-value combustion, especially applicable to the application occasions of flameless combustion of pyrolysis gas with complex components such as domestic waste, stale waste and industrial solid waste.

[0045] Further as an optional implementation manner, the control system further includes:

[0046] An air ejector is provided at the end of the air passage and is used to eject air according to a preset angle and ejection speed;

[0047] A fuel ejector is provided at the end of the fuel passage and is used to eject fuel according to a preset angle and ejection speed.

[0048] Further as an optional implementation manner, the size of the head nozzle of the ejector is adjustable, and the head nozzle can rotate axially.

[0049] Further as an optional implementation manner, the head nozzle is a conical nozzle with a straight pipe, and the inner diameter of the conical nozzle is less than or equal to one-fifth of the inner diameter of the straight pipe.

[0050] Further as an optional implementation manner, the ejection speed range of the fuel is 10 - 30 m / s, and the ejection speed range of the air is 100 - 200 m / s.

[0051] Further as an optional implementation manner, the temperature range of the combustion chamber is 1000°C - 1400°C.

[0052] The above system will be described in detail below with reference to the accompanying drawings.

[0053] As Figure 1 and Figure 2 shown, this embodiment provides a control system for a flameless burner with a wide calorific value, including a fuel component detection module, a preheater, a gas mass flow controller, an air ejector, a fuel ejector, a flue gas concentration detection module (NO x , O2), a burner temperature detection module, and a fuel calorific value calculation and control module (i.e., the control module). Among them, the fuel component detection module is located at the front end of the preheater, the gas mass flow controller is respectively arranged on the fuel passage and the air passage, an ejector is arranged at the end of the fuel passage, an ejector is arranged at the end of the air passage, and the flue gas concentration detection module is arranged at the end of the burner.

[0054] The fuel component detection module detects the component distribution of the fuel in real time, especially the proportion of H2 and CH4 components, and then transmits the detected result data to the fuel calorific value calculation and control module for calorific value analysis. At the same time, it comprehensively analyzes and evaluates the furnace temperature and the oxygen content concentration of the flue gas, and forms a control strategy to be transmitted to the control module to control the fuel and air mass flow rates and the start and stop of the preheater.

[0055] According to the instructions of the control module, preheat the air and fuel to reach the set temperature value. The waste heat temperature of the air and fuel can be adjusted in real time mainly based on the flue gas temperature and the conditions of the combustion chamber, realizing the reuse of the waste heat of the flue gas. While improving the thermal efficiency of the burner, it ensures the full combustion of low-calorific value fuel in the combustion chamber, stabilizes the combustion chamber temperature at about 1200 °C, and reduces the generation of thermal NOx.

[0056] The gas mass flow controller adjusts the appropriate air-fuel ratio according to the instructions of the control module to reach the appropriate air coefficient (1.1 - 1.5), improving the combustion efficiency and thus controlling the formation of NOx. Finally, the air and fuel pass through the ejector and are sprayed according to the instructions. The spraying angle and speed are adjusted according to the numerical simulation results. By axial rotation, the fuel and air intake positions and angles are improved, thereby increasing the gas turbulence. The speed and flow rate of the air and fuel are adjusted by the supercharger. Among them, the speed of the fuel is controlled between 10 - 30 m / s according to the calorific value and the requirements of the combustion conditions, and the air flow rate is preferably controlled between 100 - 200 m / s.

[0057] The control method based on the above control system includes the following steps:

[0058] S1. Calculate the fuel calorific value in real time according to the measurement data of the fuel composition detection module.

[0059] S2. When the fuel calorific value is between 4000 - 10000 kJ / m 3 ³, start the preheater, combine the data of the burner temperature detection module and perform steps S3 - S4; when the fuel calorific value is between 10000 - 20000 kJ / m 3 ³, combine the data of the burner temperature detection module and the oxygen concentration, calculate the fuel mass flow rate and output it to the gas mass flow controller; when the fuel calorific value is above 20000 kJ / m 3 ³, combine the data of the burner temperature detection module, calculate the fuel mass flow rate and output it to the gas mass flow controller.

[0060] S3. Calculate the mass flow rates of the fuel and air, and output the calculation results to the gas mass flow controller.

[0061] S4. According to the measurement data of the flue gas concentration detection module, adjust the gas mass flow controller to increase the speed of the fuel and air.

[0062] Figure 3 and Figure 4 are the simulation case results when the burner changes different excess air coefficients and air inlet cross-sectional areas; Figure 3 and Figure 4Intercept the temperature distribution on the central section of the burner to describe the change trend of the temperature distribution inside the burner when the excess air coefficient and the air inlet cross-sectional area change in the most intuitive way.

[0063] In summary, the control system of this embodiment has the following beneficial effects compared with the prior art:

[0064] (1) By detecting the components of the fuel at the fuel inlet and comprehensively calculating the calorific value of the fuel; since the heat load of the combustion chamber is controlled to be constant, the gas flow rate will change. Therefore, when the calorific value of the fuel changes, the fuel component detection module immediately calculates the calorific value of the fuel according to the fuel components and obtains the fuel flow rate under the specified heat load, and transmits this information to the gas flow controller to make it respond quickly, thus reflecting the effect of "wide calorific value (large fluctuation of fuel calorific value)".

[0065] (2) Combustion stability: The temperature detection module monitors the temperature of each measuring point in the burner in real time, and optimizes the air preheating temperature and air flow rate according to the temperature value to maintain stable combustion.

[0066] (3) Combustion sufficiency: First, control the air excess coefficient to be above 1.1 to ensure sufficient air supply. At the same time, the injection speed of air can be adjusted to ensure that air and fuel have enough residence time in the burner, so that the combustion is more sufficient.

[0067] (4) By setting a fuel component detection and analysis module at the source of the pyrolysis gas, the composition and calorific value of the fuel can be effectively and quickly analyzed and predicted. At the same time, using the preheater to preheat the low-calorific-value fuel can ensure the efficient and stable combustion of the fuel in the furnace, thus improving the safety of the burner; using an adjustable nozzle can solve the combustion problem of low-calorific-value fuel.

[0068] (5) By optimizing the ratio, flow rate and flow pattern of fuel and air, the flameless combustion can be effectively solved and realized, the entrainment rate can be increased and the nitrogen oxide products of the combustion flue gas can be reduced.

[0069] (6) Aiming at the characteristics of low-calorific-value fuel, such as low calorific value, insufficient combustion and easy explosion, the detection of NOx and O2 concentrations in the flue gas tail gas is set, the air flow rate entering the combustion chamber is optimized, and the temperature of the combustion chamber is maintained stable. At the same time, when the fuel calorific value is high, the air flow rate entering the combustion chamber can be optimized to avoid insufficient combustion caused by insufficient air. In addition, this embodiment is provided with a temperature detection device in the combustion chamber, which can perform temperature detection in real time and optimize the adjustment of modules such as fuel, air and preheater to ensure the stable and uniform distribution of the temperature in the combustion chamber.

[0070] As Figure 5 shown, this embodiment also provides a control method for a flameless burner, including the following steps:

[0071] S101. Obtain the component information of the fuel and obtain the calorific value of the fuel according to the component information of the fuel;

[0072] S102. If the calorific value of the fuel is between 4000 - 10000 kJ / m 3 , start the preheater, and control the mass and flow rate of the fuel and air according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas;

[0073] S103. If the calorific value of the fuel is between 10000 - 20000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas;

[0074] S104. If the calorific value of the fuel is above 20000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber.

[0075] The method of this embodiment has a corresponding relationship with the above - mentioned embodiment system. Therefore, a control method of a flameless burner in this embodiment has corresponding beneficial effects.

[0076] In some alternative embodiments, the functions / operations mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the functions / operations involved, two consecutive blocks shown may actually be executed substantially simultaneously or the blocks can sometimes be executed in the reverse order. In addition, the embodiments presented and described in the flowcharts of the present invention are provided by way of example for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Alternative embodiments are expected, where the order of various operations is changed and the sub - operations described as part of a larger operation are executed independently.

[0077] In addition, although the present invention has been described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the described functions and / or features may be integrated in a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It should also be understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. Rather, given the attributes, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the modules will be understood within the ordinary skills of an engineer. Thus, those skilled in the art can implement the present invention as set forth in the claims without undue experimentation. It should also be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0078] If the described functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0079] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a predefined sequence of executable instructions for implementing logical functions and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in conjunction with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0080] More specific examples (nonexhaustive list) of computer-readable media include the following: an electrical connection (electronic device) having one or more wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or otherwise processing as appropriate, and then stored in a computer memory.

[0081] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0082] In the foregoing description of the present specification, descriptions with reference to the terms "one embodiment / example", "another embodiment / example", or "certain embodiments / examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0083] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

[0084] The above has specifically described the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Those skilled in the art can also make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A control system for a flameless burner, characterized in that, Including: A preheater for preheating fuel and air to reach a set temperature value; Wherein the waste heat temperature of air and fuel is adjusted in real time according to the flue gas temperature and the situation of the combustion chamber to realize the reuse of the waste heat of the flue gas; A fuel component detection module is arranged at the front end of the preheater for detecting the component information of the fuel, including the proportion of H2 and CH4 components; A flue gas concentration detection module is arranged at the end of the burner for detecting the oxygen content concentration and nitride concentration of the flue gas; A temperature detection module for detecting the temperature information of the combustion chamber and the temperature of the flameless combustion zone at the tail of the combustion chamber; A control module for analyzing the fuel calorific value according to the component information of the fuel, obtaining control information according to the detected temperature information and the oxygen content concentration of the flue gas, and controlling the working state of the preheater; A gas mass flow controller is arranged on the fuel channel and the air channel for controlling the mass and flow of the output gas in the channel according to the control information to reach a preset air coefficient; The control system further includes: An air ejector is arranged at the end of the air channel for ejecting air according to a preset angle and spraying speed; wherein, the air flow rate is controlled between 100 and 200 m / s; A fuel ejector is arranged at the end of the fuel channel for ejecting fuel according to a preset angle and spraying speed; wherein, the speed of the fuel is controlled between 10 and 30 m / s according to the calorific value and the requirements of the combustion condition.

2. The control system of a flameless burner according to claim 1, characterized in that, The size of the nozzle at the head of the ejector is adjustable, and the head nozzle can rotate axially.

3. The control system of a flameless burner according to claim 2, characterized in that, The head nozzle is a conical nozzle with a straight pipe, and the inner diameter of the conical nozzle is less than or equal to one fifth of the inner diameter of the straight pipe.

4. The control system of a flameless burner according to claim 1, characterized in that, The temperature range of the combustion chamber is 1000℃ - 1400℃.

5. A control method for a flameless burner, applied to a control system of a flameless burner as described in any one of claims 1-4, characterized in that, Including the following steps: Obtain the component information of the fuel and obtain the fuel calorific value according to the component information of the fuel; If the calorific value of the fuel is between 4000 - 10000 kJ / m 3 , start the preheater, and control the mass and flow rate of the fuel and air according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas; If the calorific value of the fuel is between 10,000 and 20,000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber and the oxygen content concentration of the flue gas; If the calorific value of the fuel is above 20000 kJ / m 3 , control the mass and flow rate of the fuel according to the temperature information of the combustion chamber.

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