Stable-ignition methanol boiler ignition system and method

Abstract

The invention belongs to the technical field related to boiler equipment, and discloses a methanol boiler ignition system and method capable of achieving stable ignition, and the system comprises a methanol pipeline, an air pipeline, a built-in steam pipeline and an air channel; the methanol pipeline is connected with the built-in steam pipeline, and a methanol pump and a methanol heater are sequentially arranged on the methanol pipeline; the air pipeline is connected with the air passage, and an air heater is arranged on the air pipeline; the second end of the built-in steam pipeline penetrates through the wall face of the air channel and extends in the air channel, and the second end of the built-in steam pipeline and the second end of the air channel are connected to a combustor for ignition. The second end of the built-in steam pipeline is inserted into the air passage to extend, and only a small part of the first end of the built-in steam pipeline is located outside the air passage, so that hot air can heat and preserve heat of the built-in steam pipeline, it is guaranteed that methanol steam in the built-in steam pipeline is not liquefied, and the ignition stability is good.

Description

Technical Field

[0001] The present invention belongs to the technical field related to boiler equipment, and more specifically, relates to a methanol boiler ignition system and method with stable ignition. Background Art

[0002] In view of the tense current environmental situation, it is crucial to explore the construction of a safe, environmentally friendly and clean energy system. At present, the market for gas and oil-fired boilers is huge, and it is of great significance to study the conversion of boilers from coal and oil to low-carbon clean fuels. Among clean renewable fuels, hydrogen is clean and efficient, but it is costly and difficult to store and transport. Methanol, on the other hand, has a wide source and low price. It can be derived from coal and biomass, and can also be produced by hydrogenation of carbon dioxide. In addition, methanol is a good carrier of hydrogen, and this characteristic has led to the birth and development of alcohol hydrogen technology.

[0003] In the prior art, when methanol is used as a fuel for boiler ignition, it is often necessary to preheat the methanol to form a gaseous state for easy combustion. In the Chinese invention patent specification CN103742935A, a methanol-based boiler ignition system is disclosed. This boiler ignition system includes a methanol filter and an atomizing nozzle. The steam generated by the boiler is used to heat and atomize the filtered methanol to reach the flash point temperature of methanol, and then mixed with air and sent to the boiler for ignition. However, when the boiler load is small, the steam flow rate generated by the boiler is small, and it may not be ignited due to insufficient methanol atomization.

[0004] In the prior art, there is a fuel preheating ignition system that sets a heater for the fuel, first preheats the fuel, and then transports the heated fuel and air to the burner for ignition. Since methanol has a high saturated vapor pressure and is sensitive to temperature, when methanol vapor is transported in a pipeline, gaseous methanol will quickly reach below its dew point temperature, thereby condensing into a liquid state, causing pipeline blockage or poor fuel supply during ignition, which can easily lead to ignition failure. At the same time, too much liquid methanol passing into the boiler will lead to incomplete combustion, resulting in reduced combustion efficiency or even flameout. Such problems not only affect the normal startup and operating efficiency of the boiler, but also increase safety hazards. The existing methanol boiler ignition system has the problem that methanol vapor is easily condensed and liquefied during transportation, which can easily lead to ignition failure. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a methanol boiler ignition system and method with stable ignition, which is used to solve the problem that methanol vapor is easily condensed and liquefied during transportation in the existing methanol boiler ignition system, thus easily leading to ignition failure. By extending the built-in steam pipe for transporting methanol vapor from the inside of the air duct, the methanol vapor can be effectively prevented from liquefying in the pipe, thereby improving the ignition success rate and stability.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a methanol boiler ignition system with stable ignition, comprising a methanol pipeline, an air pipeline, a built-in steam pipe and an air duct; the first end of the methanol pipeline is connected to a methanol tank, and the second end is connected to the first end of the built-in steam pipeline, and a methanol pump and a methanol heater are sequentially arranged on the methanol pipeline; the first end of the air pipeline is connected to a blower, and the second end is connected to the first end of the air duct, and an air heater is arranged on the air pipeline; the outer diameter of the built-in steam pipe is smaller than the inner diameter of the air duct, the second end of the built-in steam pipe passes through the wall of the air duct and extends inside the air duct, and the second end of the built-in steam pipe and the second end of the air duct are respectively connected to a burner for ignition.

[0007] The methanol boiler ignition system with stable ignition provided by the present invention also includes a tapered air duct, the inner diameter of which gradually decreases from the first end to the second end, the first end of the tapered air duct is connected to the second end of the air duct, the inner diameter of the second end of the tapered air duct is larger than the outer diameter of the built-in steam pipe, the second end of the built-in steam pipe extends to be flush with the second end of the tapered air duct, and the second end of the built-in steam pipe and the second end of the tapered air duct are respectively connected to the burner.

[0008] According to the methanol boiler ignition system with stable ignition provided by the present invention, a turbulent structure is provided between the tapered air duct and the built-in steam pipe, and the turbulent structure makes the air flow at the outlet of the second end of the tapered air duct spiral.

[0009] According to the methanol boiler ignition system with stable ignition provided by the present invention, the spoiler structure includes a spiral spoiler, the spiral spoiler extends in a spiral shape from the first end to the second end of the tapered air passage, and the spiral spoiler is a curved surface structure;

[0010] Alternatively, the spoiler structure includes a plurality of spoilers distributed circumferentially between the tapered air duct and the built-in steam pipe, any of the spoilers extends along a curve in the axial direction of the tapered air duct, and the plurality of spoilers are deflected in the same direction at the second end of the tapered air duct compared to the first end.

[0011] The ignition system for a methanol boiler with stable ignition provided by the present invention further comprises a mixed combustion pipeline, wherein the second end of the built-in steam pipeline and the second end of the air duct are respectively connected to the first end of the mixed combustion pipeline, and the second end of the mixed combustion pipeline is used to be connected to a burner; an ignition needle is provided inside the second end of the mixed combustion pipeline;

[0012] And / or, an auxiliary fuel pipeline is connected to the co-firing pipeline.

[0013] According to the methanol boiler ignition system with stable ignition provided by the present invention, the air passage is in a turning structure;

[0014] A filter screen is also provided on the methanol pipeline between the methanol pump and the methanol heater, and a methanol flow meter and a methanol switch are also provided after the methanol heater;

[0015] An air flow meter and an air switch are also arranged on the air pipeline after the air heater.

[0016] According to the methanol boiler ignition system with stable ignition provided by the present invention, a temperature monitor is also provided at the first end of the built-in steam pipe, and the temperature monitor is used to monitor the temperature of the built-in steam pipe; before starting ignition, the built-in steam pipe is preheated by hot air flow, and the methanol pump and the methanol heater are used to start when it is monitored that the temperature of the built-in steam pipe reaches a first preset temperature; the temperature monitor is also used to monitor the temperature of the built-in steam pipe after starting ignition to ensure that its temperature is above the first preset temperature.

[0017] The methanol boiler ignition system with stable ignition provided by the present invention also includes an alcohol-hydrogen pipeline, a first end of the alcohol-hydrogen pipeline is connected to the methanol tank, and a second end is connected to the first end of the built-in steam pipe, and a secondary methanol pump, a thermal cracking device and an alcohol-hydrogen switch are arranged on the pipeline in sequence, an alcohol-hydrogen catalyst is arranged inside the thermal cracking device, and the alcohol-hydrogen catalyst can crack methanol into hydrogen and carbon monoxide when the temperature of the thermal cracking device reaches a second preset temperature; the alcohol-hydrogen pipeline is used for selective startup to use methanol to generate hydrogen and carbon monoxide as fuel, thereby improving the calorific value of the fuel.

[0018] According to the methanol boiler ignition system with stable ignition provided by the present invention, the heat sources of the methanol heater and the air heater include electric energy and boiler waste heat energy respectively, and when the boiler waste heat energy can meet the heating demand, the boiler waste heat energy is used.

[0019] According to another aspect of the present invention, a method for igniting a methanol boiler with stable ignition is provided. Based on any of the above-mentioned ignition systems for igniting a methanol boiler with stable ignition, the method for igniting a methanol boiler with stable ignition comprises:

[0020] First, the fan and the air heater are controlled to start, so that the air is heated to become hot air and the hot air flows along the air passage to preheat the built-in steam pipe;

[0021] When the temperature of the built-in steam pipeline reaches a preset temperature, the methanol pump and the methanol heater are controlled to start, so that the methanol is heated into methanol vapor, and the methanol vapor flows along the built-in steam pipeline for ignition.

[0022] In general, compared with the prior art, the above technical solutions conceived by the present invention provide a methanol boiler ignition system and method with stable ignition:

[0023] 1. The second end of the built-in steam pipe is inserted into the interior of the air passage for extension, and only a small part of the first end of the built-in steam pipe is located outside the air passage, so that the hot air of the air pipe can heat and insulate the built-in steam pipe when flowing along the air passage, which is beneficial to ensure that the methanol vapor in the built-in steam pipe is not liquefied and can be ignited in the form of gaseous methanol, and has the advantages of good ignition stability and high ignition success rate;

[0024] 2. The tapered air duct is set so that the hot air flows along the tapered air duct through the hot air outlet, which can effectively increase the flow rate of the hot air, thereby enhancing its turbulence intensity and making the air and fuel mixed more fully at the outlet of the tapered air duct; at the same time, the tapered structure makes the mixed gas gather in a smaller area, making the flame combustion more concentrated and the injection distance farther, thereby improving the combustion efficiency;

[0025] 3. A turbulent structure is set between the tapered air duct and the built-in steam pipe, which can output the input low-speed airflow as a high-speed spiral airflow, further enhance the turbulence intensity of the hot air and promote the mixing of fuel and air, so as to improve the ignition performance, ignition stability and ignition success rate;

[0026] 4. Before ignition begins, heat the air first and use the hot air to preheat the built-in steam pipe. After the temperature of the built-in steam pipe reaches the preset temperature, start the methanol pipeline to transport methanol vapor, which is beneficial to ensure that the methanol is ignited in the form of gaseous vapor, which is beneficial to achieve stable ignition. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the ignition system of the alcohol-hydrogen boiler with stable ignition provided by the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the air duct and the built-in steam pipeline provided by the present invention;

[0029] Figure 3 is a schematic structural diagram of a tapered airway inlet provided by the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the tapered airway outlet provided by the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of the tapered airway provided by the present invention after removing the outer wall;

[0032] Figure 6 It is a schematic diagram of the structure of another type of tapered air duct provided by the present invention after removing the outer wall;

[0033] Figure 7 This is a schematic diagram of the overall structure after adding the alcohol hydrogen pipeline provided by the present invention;

[0034] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1. Methanol pipeline; 2. Methanol tank; 3. Methanol pump; 4. Filter; 5. Methanol heater; 6. Methanol switch; 60. Methanol flow meter; 7. Air duct; 71. Hot air inlet; 72. Hot air outlet; 8. Gradually converging air duct; 81. Gradually converging air duct inlet; 82. Gradually converging air duct outlet; 83. Outer wall of gradually converging air duct; 84. Spiral spoiler; 84c. Spoiler; 9. Built-in steam pipeline; 91. Methanol steam inlet; 92. Methanol steam outlet; 10. Air pipeline; 11. Air switch; 110. Air flow meter; 12. Air heater; 13. Fan; 14. Mixed combustion pipeline; 15. Auxiliary fuel pipeline; 16. Ignition needle; 17. Burner inlet; 31. Alcohol hydrogen pipeline; 33. Auxiliary methanol pump; 34. Auxiliary filter; 35. Thermal cracking unit; 360. Alcohol hydrogen flow meter; 36. Alcohol hydrogen switch. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] See also Figure 1 and Figure 2 , this embodiment 1 provides a methanol boiler ignition system with stable ignition, the system includes a methanol pipeline 1, an air pipeline 10, a built-in steam pipe 9 and an air duct 7; the first end of the methanol pipeline 1 is connected to the methanol tank 2, and the second end is connected to the first end of the built-in steam pipeline 9, and the methanol pipeline 1 is provided with a methanol pump 3 and a methanol heater 5 in sequence; the first end of the air pipeline 10 is connected to the fan 13, and the second end is connected to the first end of the air duct 7, and the air pipeline 10 is provided with an air heater 12; the outer diameter of the built-in steam pipe 9 is smaller than the inner diameter of the air duct 7, the second end of the built-in steam pipe 9 passes through the wall of the air duct 7 and extends inside the air duct 7, and the second end of the built-in steam pipe 9 and the second end of the air duct 7 are respectively connected to the burner for ignition.

[0038] In this embodiment, a methanol pump 3 is added to the methanol pipeline 1 to control the flow rate of methanol. The first end of the methanol pipeline 1 is connected to the methanol tank 2 storing methanol fuel, and the second end is connected to the methanol vapor inlet 91, which is used to be connected to the first end of the built-in steam pipe 9. The methanol heater 5 is used to heat the methanol liquid and can be arranged on the side of the methanol pipeline 1 close to the methanol vapor inlet 91 to avoid excessive heat loss. The first end of the air pipeline 10 is connected to the air source, and the second end is connected to the hot air inlet 71, which is used to be connected to the first end of the air duct 7. The air heater 12 is used to heat the air introduced by the fan 13, and can be arranged on the side of the air pipeline 10 close to the hot air inlet 71 to avoid excessive heat loss of the air.

[0039] The methanol heater 5 is arranged on the methanol pipeline 1, and can heat the liquid methanol in the methanol pipeline 1 to convert it into methanol vapor, and then pass the methanol vapor into the built-in steam pipeline 9 through the methanol vapor inlet 91. The air heater 12 is arranged on the air pipeline 10, and can heat the cold air in the air pipeline 10 to make it hot air, and then pass the hot air into the air passage 7 through the hot air inlet 71. The second end of the built-in steam pipeline 9 is inserted into the interior of the air passage 7 for extension, and only a small part of the first end of the built-in steam pipeline 9 is located outside the air passage 7, so that the hot air of the air pipeline 10 can heat and keep the built-in steam pipeline 9 warm when flowing along the air passage 7, which is conducive to ensuring that the methanol vapor in the built-in steam pipeline 9 is not liquefied and can be ignited in the form of gaseous methanol. Therefore, the stable ignition methanol boiler ignition system of this embodiment has the advantages of good ignition stability and high ignition success rate.

[0040] This embodiment utilizes the hot air of the air pipeline 10 to heat and insulate the built-in steam pipe 9 for conveying methanol vapor, which is beneficial to prevent the methanol vapor from liquefying during the conveying process and can also prevent excessive liquid methanol from entering the boiler, thereby ensuring the normal startup and operation of the boiler and improving the combustion efficiency and safety performance.

[0041] Furthermore, the present embodiment also takes into account the limitations of traditional ignition systems in mixing fuel and air. Due to the relatively simple mixing method, it is often impossible to achieve efficient and uniform mixing of fuel and air, which further limits the combustion efficiency during the ignition process and reduces the ignition success rate. In particular, when using fuels with special combustion characteristics such as gaseous methanol (easier to liquefy and condense, and liquid methanol has a higher ignition energy), insufficient mixing effect is more likely to lead to ignition failure or unstable combustion, affecting the overall performance and stability of the boiler.

[0042] Based on this, the present embodiment proposes that the methanol boiler ignition system with stable ignition also includes a tapered air duct 8, the inner diameter of the tapered air duct 8 gradually decreases from the first end to the second end, the first end of the tapered air duct 8 is connected to the second end of the air duct 7, the inner diameter of the second end of the tapered air duct 8 is larger than the outer diameter of the built-in steam pipe 9, the second end of the built-in steam pipe 9 extends to be flush with the second end of the tapered air duct 8, and the second end of the built-in steam pipe 9 and the second end of the tapered air duct 8 are respectively connected to the burner.

[0043] like Figure 1 , Figure 3 and Figure 4 As shown, the converging air passage 8 of this embodiment is a converging structure, that is, the cross-sectional area of ​​the outer wall 83 of the converging air passage gradually decreases from the converging air passage inlet 81 to the converging air passage outlet 82. The converging air passage 8 is arranged so that the hot air flows along the converging air passage through the hot air outlet 72, which can effectively increase the flow rate of the hot air, thereby facilitating the enhancement of its turbulence intensity and making the mixing of air and fuel more complete at the converging air passage outlet 82. At the same time, the converging structure makes the mixed gas gather in a smaller area, making the flame combustion more concentrated and the injection distance farther, thereby improving the combustion efficiency.

[0044] Furthermore, a flow disturbance structure is provided between the tapered air passage 8 and the built-in steam pipe 9, and the flow disturbance structure makes the air flow at the outlet of the second end of the tapered air passage 8 spiral.

[0045] like Figure 1 , Figure 2 and Figure 3 As shown, the second end of the air duct 7 is connected to the hot air outlet 72, and the hot air outlet 72 is connected to the tapered air duct 8. Combined with the setting of the turbulent structure, the input low-speed airflow can be output as a high-speed spiral airflow, thereby enhancing the turbulence intensity of the hot air and promoting the mixing of fuel and air, so as to improve the ignition performance, ignition stability and ignition success rate.

[0046] In some specific embodiments, the spoiler structure includes a spiral spoiler 84, and the spiral spoiler 84 extends spirally from the first end to the second end of the tapered air duct 8, and the spiral spoiler 84 is a curved structure; Figure 3 , Figure 4 and Figure 5As shown, the spiral partitioning surface sheet, i.e., spiral spoiler 84, is provided inside the converging air passage 8 of this embodiment. The spiral spoiler 84, the outer wall 83 of the converging air passage, and the built-in steam pipe 9 form an air passage with a spiral structure, so that the hot air can form a spiral airflow after flowing through the converging air passage 8, thereby enhancing the disturbance ability and turbulence intensity of the hot air, and allowing the fuel and air to quickly form a uniform mixed gas. The spiral spoiler 84 specifically extends in a spiral shape in the axial direction of the built-in steam pipe 9 and has a curved surface structure in the radial direction, which is beneficial to reducing flow resistance and increasing flow velocity.

[0047] In some other specific embodiments, the spoiler structure includes a plurality of spoilers 84c distributed circumferentially between the tapered air passage 8 and the built-in steam pipe 9, any of the spoilers 84c extends along a curve in the axial direction of the tapered air passage 8, which is beneficial to reducing flow resistance, and the plurality of spoilers 84c are deflected in the same direction at the second end of the tapered air passage 8 compared to the first end. Figure 6 As shown, the number and shape of the spiral partitioning surface sheet, i.e., the spoiler 84c of this embodiment can be changed. A specific number of spoilers 84c can be evenly distributed on the circumference of the built-in steam pipe 9 according to actual needs, so that the hot air flow is evenly distributed. Any spoiler 84c is deflected at the second end of the tapered air duct 8 compared to the first end, and the deflection directions of multiple spoilers 84c are consistent, so that a spiral airflow is formed at the outlet of the second end. The shape of the spoiler 84c can be changed accordingly according to the required turbulent disturbance capacity, so that the turbulence degree of the hot air after passing through the tapered air duct meets the requirements.

[0048] Furthermore, the stable ignition methanol boiler ignition system also includes a co-combustion pipeline 14, the second end of the built-in steam pipe 9 and the second end of the air duct 7 are respectively connected to the first end of the co-combustion pipeline 14, and the second end of the co-combustion pipeline 14 is used to be connected to the burner; an ignition needle 16 is provided inside the second end of the co-combustion pipeline 14.

[0049] Optionally, an auxiliary fuel pipeline 15 is provided next to the co-combustion pipeline 14. By adding the auxiliary fuel pipeline 15 to the co-combustion pipeline 14, gaseous fuels such as natural gas and hydrogen can be mixed to assist the combustion of methanol fuel to achieve a better combustion effect.

[0050] like Figure 1-Figure 5As shown, the ignition system of the alcohol hydrogen boiler with stable ignition of this embodiment includes a methanol pipeline 1, a methanol heater 5, an air pipeline 10, an air heater 12, an air duct 7, a tapered air duct 8, a built-in steam pipeline 9, a mixed combustion pipeline 14 and an ignition needle 16. The inlet end of the air duct 7 is a hot air inlet 71, and the outlet end is a hot air outlet 72. The inlet end of the tapered air duct 8 is a tapered air duct inlet 81, and the outlet end is a tapered air duct outlet 82. The tapered air duct inlet 81 and the hot air outlet 72 are circular rings of the same size and shape, and the two overlap, and the fixing and sealing of the overlap can be achieved by welding or the like.

[0051] The inlet end of the built-in steam pipe 9 is a methanol steam inlet 91, and the outlet end is a methanol steam outlet 92. The central axis of the built-in steam pipe 9 coincides with the central axis of the tapered airway. The first end of the mixed combustion pipeline 14 is connected to the tapered airway outlet 82, and the second end is connected to the burner inlet 17. The fuel and air are fully mixed in the mixed combustion pipeline 14 for subsequent ignition. The ignition needle 16 is arranged at one end of the mixed combustion pipeline 14 close to the burner inlet 17, and is used to ignite the mixed gas after being fully mixed. After the ignition needle 16 is connected to the power supply, it can generate an electric spark for ignition. Other ignition methods can be used according to actual conditions.

[0052] like Figure 1 As shown, the inner diameter of the first end of the co-combustion pipeline 14 can be the same as the inner diameter of the second end of the tapered air passage 8, so that the first end of the co-combustion pipeline 14 is sealed and connected to the second end of the tapered air passage 8, and hot air can flow into the co-combustion pipeline 14 from the channel between the built-in steam pipe 9 and the tapered air passage 8. The built-in steam pipe 9 is connected to the co-combustion pipeline 14, and the methanol vapor is finally introduced into the co-combustion pipeline 14. The air passage 7 is connected to the tapered air passage 8, and the tapered air passage 8 is connected to the co-combustion pipeline 14. The hot air is finally introduced into the co-combustion pipeline 14 to mix with the methanol vapor to form a mixed gas, and then the ignition needle 16 ignites the mixed gas to burn it.

[0053] like Figure 1 , Figure 2 and Figure 3 As shown, the second end of the methanol pipeline 1 is connected to the methanol vapor inlet 91, and the methanol vapor inlet 91 is connected to the built-in steam pipeline 9, so that the methanol vapor formed after the methanol liquid is heated by the methanol heater 5 is passed into the built-in steam pipeline 9 through the methanol vapor inlet 91. The second end of the built-in methanol vapor pipeline is connected to the methanol vapor outlet 92, and the methanol vapor outlet 92 is connected to the mixed combustion pipeline 14, so that the methanol vapor is passed into the mixed combustion pipeline 14 to mix with the hot air.

[0054] Optionally, the air passage 7 is a steering structure, that is, it is set as a steering air passage; the second end of the air pipeline 10 is connected to the hot air inlet 71, and the hot air inlet 71 is connected to the steering air passage, so that the flow direction of the hot air is changed after entering the steering air passage, so that the flow directions of the methanol vapor and the hot air are consistent, which is conducive to the mixing and combustion of the two and ensures the uniformity of the mixing. The setting of the steering air passage can better extend the built-in steam pipeline 9 inside it, and the methanol pipeline 1 and the air pipeline 10 can be set in two directions to avoid interference between the two, which is convenient for setting.

[0055] The air duct 7 can adjust the steering angle according to actual conditions to ensure that the central axis of the hot air outlet 72 coincides with the central axis of the built-in steam pipe 9. Preferably, the air duct 7 adopts a smooth transition to reduce the energy loss of the hot air flow.

[0056] The methanol pipeline 1 is provided with a filter 4 between the methanol pump 3 and the methanol heater 5, and a methanol flow meter 60 and a methanol switch 6 are provided after the methanol heater 5; the air pipeline 10 is provided with an air flow meter 110 and an air switch 11 after the air heater 12. The filter 4 is provided in the methanol pipeline 1 to filter impurities in the methanol. Figure 1 As shown, the methanol tank 2 is connected to the methanol pump 3, the methanol pump 3 is connected to the filter 4, and the three are connected to the methanol pipeline 1 in sequence to deliver the pure methanol fuel to the mixed combustion pipeline 14. The fan 13 is connected to one end of the air pipeline 10 to pass air into the mixed combustion pipeline 14.

[0057] This embodiment further includes a methanol switch 6 and an air switch 11. The methanol switch 6 is provided on the methanol pipeline 1, between the methanol heater 5 and the built-in steam pipeline 9, and is used to control the flow of methanol vapor; the air switch 11 is provided on the air pipeline 10, between the air heater 12 and the air passage 7, and is used to control the flow of hot air. Preferably, the methanol switch 6 and the air switch 11 should be provided with a methanol flow meter 60 and an air flow meter 110, respectively, for monitoring the flow of methanol vapor and the flow of air, so as to ensure that the fuel and the air are mixed in proportion.

[0058] Insulating materials can be used to wrap the methanol pipeline 1 and the air pipeline 10 after the methanol heater 5 and the air heater 12 to reduce the impact of the external environment on the pipeline temperature. Specifically, the air duct 7 and the tapered duct 8 and the pipeline surface between the air duct 7 and the air heater 12 are wrapped with a layer of insulation material to reduce the heat loss caused by the circulation of hot air after being heated by the air heater 12. In addition to the part wrapped by the air duct 7 and the tapered duct 8, the built-in steam pipeline 9 also reserves a small section of pipeline for connection with the methanol pipeline 1 and installation of temperature monitoring equipment, so as to reflect in real time whether the temperature of the built-in steam pipeline 9 meets the ignition requirements. The pipeline surface between this section of the pipeline and the methanol heater 5 is wrapped with a layer of insulation material to reduce the heat loss of methanol vapor.

[0059] Temperature sensors, pressure sensors and other sensor elements and flow meters can also be added to the heater and subsequent pipelines to monitor key parameters such as fuel and air flow, pipeline temperature and pressure in real time, and adjust preheating temperature, flow and other parameters based on the monitoring results to ensure a smooth ignition process.

[0060] In some specific embodiments, a temperature monitor is also provided at the first end of the built-in steam pipe 9, and the temperature monitor is used to monitor the temperature of the built-in steam pipe 9; the built-in steam pipe 9 is preheated by hot air flow before starting ignition, and the methanol pump 3 and the methanol heater 5 are used to start when the temperature of the built-in steam pipe 9 reaches the first preset temperature; the temperature monitor is also used to monitor the temperature of the built-in steam pipe 9 after starting ignition to ensure that its temperature is above the first preset temperature. A portion of the built-in steam pipe 9 can be reserved for pipeline connection and installation of temperature monitoring equipment. After starting ignition, when the temperature of the built-in steam pipe 9 is monitored to be lower than the first preset temperature, the heating temperature of the methanol heater 5 and / or the air heater 12 can be adjusted to increase the temperature of the built-in steam pipe 9 to avoid liquefaction of methanol vapor in the pipe. The first preset temperature can be 65°C.

[0061] In some specific embodiments, the heat sources of the methanol heater 5 and the air heater 12 include electric energy and boiler waste heat energy, respectively, and when the boiler waste heat energy can meet the heating demand, the boiler waste heat energy is used.

[0062] In this embodiment, the methanol heater 5 and the air heater 12 are multi-heat source heaters. The methanol heater 5 and the air heater 12 need to have a heat source with cold start heating capability, such as an electric heating source, to ensure that the embodiment can operate stably under normal conditions. In addition, since the boiling point of methanol is not high, only about 338K at room temperature, the waste heat in the exhaust gas can be collected after the boiler is running stably as the heat source of the methanol heater 5 and the air heater 12. When the waste heat meets the heating requirements, the electric heating source can be turned off to achieve energy saving and environmental protection.

[0063] Whether the boiler waste heat can meet the heating demand can be determined by monitoring the temperature of the methanol vapor heated by the methanol heater 5 and the temperature of the air heated by the air heater 12. The methanol heater 5 and the air heater 12 are equipped with temperature monitoring equipment, such as thermocouples, to monitor whether the temperature of the methanol vapor heated by the methanol heater 5 and the temperature of the hot air heated by the air heater 12 reach the required temperature, so as to ensure that the heaters can work while meeting the ignition requirements.

[0064] Furthermore, the alcohol-hydrogen boiler ignition system with stable ignition of the present embodiment further includes an alcohol-hydrogen pipeline 31, the first end of which is connected to the methanol tank 2, and the second end is connected to the first end of the built-in steam pipe 9, on which are sequentially provided an auxiliary methanol pump 33, a thermal cracking device 35 and an alcohol-hydrogen switch 36, wherein an alcohol-hydrogen catalyst is provided inside the thermal cracking device 35, and the alcohol-hydrogen catalyst can crack methanol into hydrogen and carbon monoxide when the temperature of the thermal cracking device 35 reaches a second preset temperature. The alcohol-hydrogen pipeline 31 is used for selective startup to utilize methanol to generate hydrogen and carbon monoxide as fuel, thereby increasing the calorific value of the fuel.

[0065] The alcohol hydrogen pipeline 31 is turned on, that is, the auxiliary methanol pump 33, the thermal cracking device 35 and the alcohol hydrogen switch 36 are turned on, and the temperature of the thermal cracking device 35 reaches the second preset temperature, so that methanol can be cracked into hydrogen and carbon monoxide under the catalytic action of the alcohol hydrogen catalyst, and the generated hydrogen and carbon monoxide are transported to the built-in steam pipeline 9 as supplementary fuel for ignition and combustion. The second preset temperature can be determined according to the type of alcohol hydrogen catalyst, with the purpose of reaching the catalytic temperature of the corresponding catalyst. Optionally, the second preset temperature is greater than or equal to 260 degrees Celsius. Specifically, the alcohol hydrogen pipeline 31 is used to crack methanol into hydrogen and carbon monoxide using boiler waste heat as a heat source, and transport it to the boiler for combustion. That is, the alcohol hydrogen pipeline 31 is used to open when the waste heat temperature of the boiler is greater than the second preset temperature. At this time, the waste heat energy of the boiler is the heat source of the thermal cracking device 35. Thereby improving energy utilization efficiency. The waste heat energy of the boiler is the heat energy of the flue gas after the boiler is burned.

[0066] The switch in the above embodiments is a valve component, such as a solenoid valve.

[0067] The second embodiment provides a method for igniting a methanol boiler with stable ignition. The method is based on the ignition system for igniting a methanol boiler with stable ignition described in any of the above embodiments. The method for igniting a methanol boiler with stable ignition includes:

[0068] First, the fan 13 and the air heater 12 are controlled to start, so that the air is heated to become hot air and the hot air flows along the air passage 7 to preheat the built-in steam pipe 9;

[0069] When the temperature of the built-in steam pipe 9 reaches a preset temperature, the methanol pump 3 and the methanol heater 5 are controlled to start, so that the methanol is heated into methanol vapor, and the methanol vapor flows along the built-in steam pipe 9 for ignition.

[0070] Furthermore, the air and methanol can be heated by using the waste heat energy of flue gas generated by electric energy or auxiliary fuel. After the combustion of the methanol boiler is stable, the waste heat energy can be used as the heat source for methanol heating and air heating after the preset operation time. The auxiliary fuel pipeline 15 can be fed with auxiliary gas fuel to assist the combustion of methanol fuel, or the auxiliary gas fuel can be used for combustion first. After the boiler runs stably and can generate high-temperature flue gas, the high-temperature flue gas is used as the heat source to operate the methanol heater 5 and the air heater 12 of this embodiment. After the methanol fuel can burn stably to generate high-temperature flue gas, the auxiliary fuel pipeline 15 is closed.

[0071] Furthermore, the technical problem to be solved by this embodiment is to solve the problem of ignition failure caused by liquefaction of gaseous methanol when passing through the pipeline when using preheated methanol for ignition. Gaseous methanol is easily liquefied in the pipeline, causing pipeline blockage or ignition failure, seriously affecting the safety and efficiency of boiler operation. In addition, the traditional ignition system has limited mixing effect on fuel and air, further reducing the ignition success rate. Therefore, this embodiment provides a stable ignition alcohol hydrogen boiler ignition system, thereby preventing methanol vapor from being liquefied through the pipeline, and also optimizing the mixing effect of fuel and air by adding a spiral airway structure.

[0072] The present embodiment provides a stable ignition alcohol hydrogen boiler ignition system comprising: a mixed combustion pipeline 14, a methanol pipeline 1, a methanol heater 5, an air pipeline 10, an air heater 12, a steering airway, a built-in steam pipeline 9, a spiral tapered airway, i.e., a tapered airway 8 with a turbulent structure, and an ignition needle 16; the mixed combustion pipeline 14 has a certain length, is used for mixing heated air and methanol vapor, one end is connected to the tapered airway outlet 82 and the methanol vapor outlet 92, and the other end is connected to the burner inlet 17. One end of the methanol pipeline 1 is connected to the methanol tank 2, and the other end is connected to the built-in steam pipeline 9. Liquid methanol absorbs heat after passing through the methanol heater 5 to become methanol vapor, and the methanol vapor is passed into the built-in steam pipeline 9. The methanol heater 5 is used to heat liquid methanol into methanol vapor. The ignition energy of methanol vapor is low, which is conducive to the ignition of methanol fuel.

[0073] One end of the air pipeline 10 is connected to the fan 13, and the other end is connected to the hot air inlet 71. The air is heated to a sufficiently high temperature in the air heater 12. The air is heated to a relatively high temperature, and the hot air is used for subsequent heating and heat preservation of the methanol steam pipeline. The turning airway, i.e., the air airway 7 set as a turning structure, is used to change the flow direction of the hot air. The interior of the airway is penetrated by part of the built-in steam pipe 9, and the hot air can heat and heat preserve the section of the methanol steam pipeline. Most of the built-in methanol steam pipeline is in the air turning airway and the air spiral tapered airway. This part of the pipeline is wrapped by hot air, which prevents the methanol steam from liquefying in the pipeline and causing ignition failure.

[0074] The air spiral converging airway has a spiral structure, which outputs the inflowing hot air as a spiral airflow. Its converging structure can increase the air flow rate, and the two can enhance the mixing effect of hot air and methanol vapor. At the same time, the air spiral converging airway wraps the outlet end of the built-in methanol vapor pipeline, which is conducive to the mixing of hot air and methanol vapor and can prevent the methanol vapor from liquefying in this section. The ignition needle 16 is set at the end of the mixed combustion pipeline to ignite the fully mixed mixed gas.

[0075] The working principle of this embodiment is as follows:

[0076] Preheating stage: Turn on the air heater 12, the fan 13 and the air switch 11, and generate hot air that flows through the air flow meter 110, the air switch 11, the turning air duct, the tapered air duct 8 and the mixed combustion pipeline 14 in sequence, and finally flows into the furnace from the burner inlet 17. In this process, the hot air heats the built-in steam pipe 9, and the hot air flowing into the furnace can also provide a small amount of heat for the boiler, and at the same time blow away the exhaust gas in the furnace, thereby improving the safety of the combustion process.

[0077] Ignition stage: after the temperature of the built-in steam pipe 9 meets the requirement, turn on the methanol pump 3, the methanol heater 5 and the methanol switch 6, and the methanol liquid is pumped from the methanol tank 2 into the methanol heater 5 by the methanol pump 3. The generated methanol vapor flows through the methanol flowmeter 60, the methanol switch 6 and the built-in steam pipe 9 in sequence, and then is fully mixed with the high-speed spiral hot air flow in the co-combustion pipeline 14 to form a mixed gas. The ignition needle 16 is turned on to generate an electric spark to ignite the mixed gas, and the generated flame enters the furnace from the burner inlet 17 for stable combustion.

[0078] Combustion stage: After the combustion is stable, the heat sources of the methanol heater 5 and the air heater 12 can be changed according to actual needs. Preferably, the high-temperature flue gas generated by the boiler is used as the heat source to improve the overall thermal efficiency. Optionally, gas fuel is introduced into the auxiliary fuel pipeline 15 to assist combustion and increase the heat supplied by combustion.

[0079] Alternatively, if Figure 7As shown, the methanol pipeline 1 can be connected in parallel with a similar alcohol-hydrogen pipeline 31, and the methanol heater 5 can be replaced with a thermal cracking device 35. The thermal cracking device 35 contains a specific alcohol-hydrogen catalyst, which can crack methanol into hydrogen and carbon monoxide within a certain temperature range to improve the calorific value of methanol fuel. After the boiler operates normally, the high-temperature tail gas discharged by the boiler is used to make the thermal cracking device 35 reach the catalytic temperature, and the catalytically generated hydrogen and carbon monoxide are introduced into the mixed combustion pipeline 14 together with the methanol vapor to participate in combustion, thereby improving the combustion efficiency.

[0080] The working principle of alcohol hydrogen pipeline 31 is as follows:

[0081] After the combustion is stable, the high-temperature tail gas discharged from the boiler makes the thermal cracking device 35 reach the catalytic temperature, the auxiliary methanol pump 33 is turned on, and the methanol liquid flows through the auxiliary methanol pump 33 and the auxiliary filter 34 and enters the thermal cracking device 35. The methanol fuel is cracked into cracked gas with hydrogen and carbon monoxide as main components in the thermal cracking device 35. The cracked gas flow rate is controlled by adjusting the opening of the alcohol hydrogen switch 36, and the cracked gas flow rate is monitored in real time by the alcohol hydrogen flowmeter 360. The cracked gas in the alcohol hydrogen pipeline 31 and the methanol vapor in the methanol pipeline 1 enter the built-in steam pipeline 9 to mix, and finally enter the mixed combustion pipeline 14 together to participate in combustion.

[0082] This embodiment uses methanol as boiler ignition fuel and is applicable to methanol boilers and alcohol hydrogen boilers. The ignition energy of methanol is reduced by preheating methanol and air, which is conducive to the ignition of methanol fuel. A special air channel 7 is designed to avoid liquefaction of methanol vapor in the pipeline and cause ignition failure. The designed spiral tapered air channel can enhance air turbulence and promote the mixing of fuel and air, thereby improving the success rate and stability of methanol fuel ignition.

[0083] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A methanol boiler ignition system with stable ignition, characterized in that: It comprises a methanol pipeline, an air pipeline, a built-in steam pipeline and an air duct; the first end of the methanol pipeline is connected to the methanol tank, the second end is connected to the first end of the built-in steam pipeline, and a methanol pump and a methanol heater are sequentially arranged on the methanol pipeline; the first end of the air pipeline is connected to the fan, the second end is connected to the first end of the air duct, and an air heater is arranged on the air pipeline; the outer diameter of the built-in steam pipeline is smaller than the inner diameter of the air duct, the second end of the built-in steam pipeline passes through the wall of the air duct and extends inside the air duct, and the second end of the built-in steam pipeline and the second end of the air duct are respectively connected to the burner for ignition.

2. The methanol boiler ignition system with stable ignition according to claim 1, characterized in that: It also includes a tapered air duct, the inner diameter of which gradually decreases from the first end to the second end, the first end of the tapered air duct is connected to the second end of the air duct, the inner diameter of the second end of the tapered air duct is larger than the outer diameter of the built-in steam pipe, the second end of the built-in steam pipe extends to be flush with the second end of the tapered air duct, and the second end of the built-in steam pipe and the second end of the tapered air duct are respectively connected to the burner.

3. The stable ignition methanol boiler ignition system according to claim 2, characterized in that: A flow disturbance structure is provided between the tapered air passage and the built-in steam pipe, and the flow disturbance structure causes the air flow at the outlet of the second end of the tapered air passage to be spiral.

4. The stable ignition methanol boiler ignition system according to claim 3, characterized in that: The spoiler structure comprises a spiral spoiler, the spiral spoiler extends in a spiral shape from the first end to the second end of the tapered air passage, and the spiral spoiler is a curved surface structure; Alternatively, the spoiler structure includes a plurality of spoilers distributed circumferentially between the tapered air duct and the built-in steam pipe, any of the spoilers extends along a curve in the axial direction of the tapered air duct, and the plurality of spoilers are deflected in the same direction at the second end of the tapered air duct compared to the first end.

5. The methanol boiler ignition system with stable ignition according to any one of claims 1 to 4, characterized in that: It also includes a mixed combustion pipeline, the second end of the built-in steam pipeline and the second end of the air duct are respectively connected to the first end of the mixed combustion pipeline, and the second end of the mixed combustion pipeline is used to connect to the burner; an ignition needle is provided inside the second end of the mixed combustion pipeline; And / or, an auxiliary fuel pipeline is connected to the co-firing pipeline.

6. The methanol boiler ignition system with stable ignition according to any one of claims 1 to 4, characterized in that: The air passage is in a turning structure; A filter screen is also provided on the methanol pipeline between the methanol pump and the methanol heater, and a methanol flow meter and a methanol switch are also provided after the methanol heater; An air flow meter and an air switch are also arranged on the air pipeline after the air heater.

7. The methanol boiler ignition system with stable ignition according to any one of claims 1 to 4, characterized in that: A temperature monitor is also provided at the first end of the built-in steam pipe, and the temperature monitor is used to monitor the temperature of the built-in steam pipe; before starting ignition, the built-in steam pipe is preheated by hot air flow, and the methanol pump and the methanol heater are used to start when it is monitored that the temperature of the built-in steam pipe reaches a first preset temperature; the temperature monitor is also used to monitor the temperature of the built-in steam pipe after starting ignition to ensure that its temperature is above the first preset temperature.

8. The methanol boiler ignition system with stable ignition according to any one of claims 1 to 4, characterized in that: It also includes an alcohol-hydrogen pipeline, a first end of which is connected to the methanol tank, and a second end of which is connected to the first end of the built-in steam pipeline, on which a secondary methanol pump, a thermal cracking device and an alcohol-hydrogen switch are arranged in sequence, an alcohol-hydrogen catalyst is arranged inside the thermal cracking device, and the alcohol-hydrogen catalyst can crack methanol into hydrogen and carbon monoxide when the temperature of the thermal cracking device reaches a second preset temperature; the alcohol-hydrogen pipeline is used for selective startup to utilize methanol to generate hydrogen and carbon monoxide as fuel, thereby increasing the calorific value of the fuel.

9. The methanol boiler ignition system with stable ignition according to any one of claims 1 to 4, characterized in that: The heat sources of the methanol heater and the air heater include electric energy and boiler waste heat energy respectively, and when the boiler waste heat energy can meet the heating demand, the boiler waste heat energy is used.

10. A method for igniting a methanol boiler with stable ignition, characterized in that: Based on the methanol boiler ignition system with stable ignition according to any one of claims 1 to 9, the methanol boiler ignition method with stable ignition includes: First, the fan and the air heater are controlled to start, so that the air is heated to become hot air and the hot air flows along the air passage to preheat the built-in steam pipe; When the temperature of the built-in steam pipeline reaches a preset temperature, the methanol pump and the methanol heater are controlled to start, so that the methanol is heated into methanol vapor, and the methanol vapor flows along the built-in steam pipeline for ignition.

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