Methanol / ammonia gas integrated heating furnace

Abstract

The invention relates to a methanol / ammonia gas integrated heating furnace, and belongs to the technical field of heating equipment. The problems that an existing heating furnace is single in fuel type and high in carbon emission are solved. The device comprises an ammonia storage tank, a pressure reducing valve, an ammonia gas cracking chamber, a methanol storage tank, a furnace body, a flue gas fan and an air fan, the ammonia storage tank, the pressure reducing valve, the ammonia gas cracking chamber and a combustor are sequentially connected through pipelines, an atomizing nozzle is installed on the combustor, the methanol storage tank is connected with the atomizing nozzle through a pipeline, and the flue gas fan is connected with the air fan. And liquid methanol fuel in the methanol storage tank enters the combustor for combustion through the atomizing nozzle. The heating device has the advantage of being compatible with various low-carbon fuels to achieve heating, and heat generated by combustion can be fully utilized.

Description

Technical Field

[0001] This invention relates to an integrated methanol / ammonia heating boiler, belonging to the technical field of heating equipment. Background Technology

[0002] In existing technologies, the fuels commonly used in heating boilers mainly include the following categories: Coal: A traditional fuel with high calorific value and low cost, but it is highly polluting and its use has been restricted or phased out in many areas.

[0003] Natural gas is clean and efficient, producing almost no smoke or sulfur dioxide after combustion. It is one of the mainstream fuels for urban central heating. However, the installation and maintenance costs are relatively high, and it is difficult to renovate existing houses.

[0004] Biomass fuels, such as biomass pellets, straw briquettes, and wood chips, are renewable energy sources with good environmental performance, making them suitable for use in rural areas. However, they have higher site and insurance costs.

[0005] Fuel oil (such as diesel and heavy oil): High thermal efficiency and quick start-up, but high operating costs, and is mostly used in places with high requirements for heating quality.

[0006] Electricity: Heating is provided by electric boilers or heat pumps, which is clean and pollution-free, but has high operating costs and is suitable for areas with high environmental protection requirements.

[0007] Liquefied petroleum gas (such as propane): suitable for areas without natural gas pipeline networks, easy to transport and store, but relatively expensive.

[0008] Most importantly, existing heating stoves all use only one of the commonly used fuels mentioned above, resulting in a limited fuel variety. Furthermore, the heat generated during fuel combustion is not fully utilized, leading to energy waste and significant carbon dioxide emissions. Therefore, a new type of green heating stove is urgently needed to address the problems of limited fuel variety, severe energy waste, and excessive carbon emissions associated with existing stoves. Summary of the Invention

[0009] The present invention aims to solve the problem of existing heating furnaces having a single type of fuel and excessive carbon emissions, and provides a methanol / ammonia integrated heating furnace.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: An integrated methanol / ammonia heating furnace includes an ammonia storage tank, a pressure reducing valve, an ammonia cracking chamber, a methanol storage tank, a furnace body, a flue gas fan, and an air fan. The furnace body houses a burner and a heat exchange chamber. The air fan is connected to the burner via piping. The ammonia storage tank, pressure reducing valve, ammonia cracking chamber, and burner are sequentially connected via piping. An atomizing nozzle is installed on the burner. The methanol storage tank is connected to the atomizing nozzle via piping. Liquid methanol fuel in the methanol storage tank enters the burner through the atomizing nozzle for combustion. A circulating water heat exchanger is installed in the heat exchange chamber, and an ammonia heater is installed in the ammonia cracking chamber. The flue gas outlet of the heat exchange chamber, the flue gas fan, and the inlet of the ammonia heater are sequentially connected via piping. The outlet of the ammonia heater is connected to the outside air.

[0011] Furthermore, the walls of the ammonia cracking chamber are coated with a Ni-based catalyst.

[0012] Furthermore, an ammonia flow meter is installed on the pipeline between the ammonia storage tank and the ammonia cracking chamber.

[0013] Furthermore, an alcohol fuel flow meter is installed on the pipeline between the methanol storage tank and the atomizing nozzle.

[0014] Furthermore, an air flow meter is installed on the pipeline between the air blower and the burner.

[0015] Furthermore, ball valves and check valves are installed on the pipelines between the ammonia storage tank and the ammonia cracking chamber, as well as on the pipelines between the methanol storage tank and the atomizing nozzle.

[0016] Furthermore, a water pump is connected to the outlet pipe of the circulating water heat exchanger.

[0017] Furthermore, the circulating water heat exchanger and the heat user form a water circulation system.

[0018] Compared with the prior art, the present invention has the following advantages: The methanol / ammonia integrated heating boiler of the present invention can use ammonia alone, methanol alone, or a mixture of ammonia and alcohol fuels, offering the advantage of fuel versatility. Furthermore, methanol and ammonia are zero-carbon or low-carbon fuels, which can significantly reduce carbon dioxide emissions for heating.

[0019] The heat used in ammonia cracking is provided by the flue gas in the combustion chamber, which is "waste gas" after the heat has been absorbed by the circulating water heat exchanger. Therefore, the methanol / ammonia integrated heating furnace of the present invention can make full use of the heat generated by combustion.

[0020] The hydrogen produced after pyrolysis burns extremely quickly, and when mixed with air, it burns stably over a wider concentration range. When the pyrolyzed mixture burns, hydrogen acts as an "ignition source," accelerating the reaction and improving overall combustion efficiency. This not only allows for a more complete release of fuel energy but also reduces heat loss due to incomplete combustion. Simultaneously, it can also reduce NO in the flue gas. x It has a low content and is environmentally friendly.

[0021] Methanol fuel is supplied by methanol storage tanks. After being atomized by atomizing nozzles, the specific surface area of ​​the fuel per unit volume increases exponentially, and the gas-liquid contact area is multiplied, achieving instantaneous and efficient mixing of fuel molecules with air, thereby achieving stable combustion. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structural composition of the methanol / ammonia integrated heating furnace of the present invention.

[0023] In the picture: 1. Ammonia storage tank; 2. Pressure reducing valve; 3. Ammonia cracking chamber; 4. Methanol storage tank; 5. Furnace body; 51. Burner; 52. Heat exchange chamber; 6. Flue gas fan; 7. Air fan; 8. Atomizing nozzle; 9. Circulating water heat exchanger; 10. Ammonia heater; 11. Ammonia flow meter; 12. Alcohol fuel flow meter; 13. Air flow meter; 14. Ball valve; 15. Check valve; 16. Water pump. Detailed Implementation

[0024] Specific implementation method one: Combining Figure 1 This description of embodiments provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] A methanol / ammonia integrated heating furnace includes an ammonia storage tank 1, a pressure reducing valve 2, an ammonia cracking chamber 3, a methanol storage tank 4, a furnace body 5, a flue gas fan 6, and an air fan 7. The furnace body 5 houses a burner 51 and a heat exchange chamber 52. The air fan 7 is connected to the burner 51 via a pipeline. The ammonia storage tank 1, pressure reducing valve 2, ammonia cracking chamber 3, and burner 51 are sequentially connected via pipelines. An atomizing nozzle 8 is installed on the burner 51. The methanol storage tank 4 is connected to the atomizing nozzle 8 via a pipeline. Liquid methanol fuel in the methanol storage tank 4 enters the burner 51 for combustion through the atomizing nozzle 8. A circulating water heat exchanger 9 is installed in the heat exchange chamber 52. An ammonia heater 10 is installed in the ammonia cracking chamber 3. The flue gas outlet of the heat exchange chamber 52, the flue gas fan 6, and the inlet of the ammonia heater 10 are sequentially connected via pipelines. The outlet of the ammonia heater 10 is connected to the outside air.

[0026] The furnace body 5 structure, which is equipped with a burner 51 and a heat exchange chamber 52, is existing technology, and its specific structure and working principle will not be described in detail here.

[0027] The methanol / ammonia integrated heating boiler of the present invention includes three systems: an ammonia cracking system, a combustion system, and a water circulation system. The ammonia cracking system includes an ammonia storage tank 1, a pressure reducing valve 2, an ammonia cracking chamber 3, an ammonia heater 10, and a flue gas fan 6. The combustion system includes a methanol storage tank 4, an atomizing nozzle 8, a burner 51, and an air fan 7. The water circulation system includes a circulating water heat exchanger 9 and a circulation pipeline connecting the circulating water heat exchanger 9 and the heat user.

[0028] Ammonia, as a fuel with no CO2 combustion products, has the following advantages: it is easy to store and transport, increasing its effective loading mass within the same volume; it can be transported over long distances via pipelines, highways, and railways, indicating low transportation costs; and ammonia production processes are mature, using hydrogen and nitrogen as raw materials, with the latest processes including photocatalysis, plasma, recycling, and nitrogenase methods. However, ammonia has disadvantages such as high ignition energy, low combustion speed, and a narrow flammability range. Ammonia cracking produces ammonia gas containing hydrogen, which has advantages such as fast combustion speed and low ignition energy, significantly mitigating the disadvantages of ammonia combustion. Therefore, re-combustion of cracked ammonia is a highly efficient method for burning ammonia.

[0029] Methanol is also liquid at room temperature and pressure, making its storage and transportation costs low. Furthermore, methanol fuel can be obtained renewablely, synthesized from raw materials such as green hydrogen, carbon dioxide, or biomass, making it an important green and clean fuel for achieving carbon emission reduction goals.

[0030] In this invention, the liquid ammonia in the ammonia storage tank 1 is depressurized and then enters the ammonia cracking chamber 3 in gaseous form. The inner wall of the ammonia cracking chamber 3 is coated with a Ni-based catalyst. Under the combined action of the heat provided by the ammonia heater 10 and the catalyst, the ammonia is cracked to generate cracked gas containing hydrogen, which then enters the combustion zone for combustion.

[0031] The alcohol fuel in the methanol storage tank 4 is atomized by the atomizing nozzle 8, which improves the mixing effect of fuel and air, thereby making it easier to burn.

[0032] Methanol fuel has a high latent heat of vaporization and is difficult to fully contact with air in its liquid state. The atomizing nozzle 8 breaks down liquid methanol fuel into tiny droplets, significantly increasing the fuel's surface area. This increased surface area allows the fuel droplets to contact air more quickly, forming a homogeneous gas-liquid mixture. This is fundamental for complete combustion. If fuel enters the combustion chamber as large droplets, localized oxygen deficiency or fuel aggregation can easily occur, leading to incomplete combustion. Secondly, it accelerates fuel evaporation and ignition. Although methanol fuel has some volatility, its evaporation rate in the liquid state is much lower than that in the gaseous state. The atomized droplets have a large heated surface area, allowing them to evaporate rapidly into a gaseous state in the high-temperature environment of the combustion chamber, shortening the conversion time from liquid to gas. Gaseous fuel reaches ignition temperature more easily, reducing ignition delay. If the fuel is not atomized, large droplets require a longer evaporation time, potentially causing some fuel to be expelled before ignition, resulting in energy waste or pollutant emissions. Furthermore, it improves combustion efficiency and reduces pollutant emissions. Full atomization ensures a more uniform mixture of fuel and oxygen, resulting in a more complete combustion reaction and maximizing the release of the fuel's chemical energy. Meanwhile, incomplete combustion easily produces pollutants such as carbon monoxide and unburned hydrocarbons, while atomized combustion significantly reduces the emissions of these pollutants. Furthermore, uneven mixing during the combustion of alcohol fuels can lead to localized high temperatures, generating nitrogen oxides. Proper atomization can control the mixing ratio to avoid these localized high temperatures, further reducing pollution.

[0033] The inlet of the circulating water heat exchanger 9 is the cold water end, and the outlet is the hot water end.

[0034] The circulating water heat exchanger 9 uses the heat from the high-temperature flue gas generated after the combustion of ammonia cracking gas and alcohol fuel to heat the cold circulating water entering it. The heated circulating water is pumped by water pump 16 to the heat-using area, i.e. the heat user. The used circulating water re-enters the circulating water heater through an external pipeline, and so on.

[0035] The water inlet of the air fan 7 is connected to the outside air, and the air fan 7 provides oxygen for combustion in the burner 51.

[0036] The ammonia flow meter 11, alcohol fuel flow meter 12, and air flow meter 13 are appropriately adjusted to find the optimal matching value between ammonia and methanol fuel, so that the fuel can be fully burned and thus improve energy utilization.

[0037] The methanol / ammonia integrated heating furnace of the present invention can use ammonia alone, methanol alone, or a mixture of ammonia and methanol fuel, which has the advantage of fuel diversification.

[0038] The heat used in ammonia cracking is provided by the flue gas in the combustion chamber, which is "exhaust gas" after the heat has been absorbed by the circulating water heat exchanger 9. Therefore, the methanol / ammonia integrated heating furnace of the present invention can make full use of the heat generated by combustion.

[0039] Unlike direct combustion of ammonia, combustion after ammonia cracking overcomes the drawbacks of ammonia, such as high ignition energy, low combustion speed, and narrow flammability range. The biggest problem with direct ammonia combustion is its extremely slow combustion speed and susceptibility to incomplete combustion. This is because the NH bonds in ammonia molecules require significant energy to break; if oxygen mixing is uneven or combustion time is insufficient, unreacted ammonia may remain or intermediate products (such as N₂O) may form. In contrast, the hydrogen produced after cracking burns extremely quickly, and when mixed with air, it burns stably over a wider concentration range. When the hydrogen-rich mixture from cracking burns, hydrogen acts as an "igniter," accelerating the reaction and improving overall combustion efficiency. This not only allows for more complete release of fuel energy but also reduces heat loss due to incomplete combustion. It also reduces NO₂ in the flue gas. x It has a low content and is environmentally friendly.

[0040] Atomizing methanol fuel improves the mixing of fuel and air. Methanol fuel typically has a high latent heat of vaporization and is difficult to fully contact with air in its liquid state. The atomizing nozzle 8 breaks down liquid alcohol fuel into tiny droplets, greatly increasing the fuel's surface area. This increased surface area allows the fuel droplets to contact oxygen in the air more quickly, forming a uniform gas-liquid mixture. Furthermore, it improves combustion efficiency and reduces pollutant emissions.

[0041] Working principle: Liquid ammonia is depressurized by pressure reducing valve 2 and converted into ammonia gas. The ammonia gas then enters the ammonia cracking chamber 3, whose walls are coated with a Ni-Pt / Al2O3 catalyst. The heat required for ammonia cracking is provided by the flue gas from the combustion furnace after heating the cold circulating water. At a certain temperature, the ammonia gas is catalytically cracked into hydrogen-containing cracked gas. Methanol fuel is supplied by methanol storage tank 4. After being atomized by atomizing nozzle 8, the specific surface area per unit volume of fuel increases exponentially, and the gas-liquid contact area doubles, achieving instantaneous and efficient mixing of fuel molecules with air, thus achieving stable combustion. Air is supplied by a fan. By adjusting the ammonia flow meter 11, alcohol fuel flow meter 12, and air flow meter 13, the ammonia cracked gas and methanol fuel are burned at their optimal equivalence ratios, ensuring complete combustion. The combustion of ammonia cracked gas and methanol fuel produces high-temperature flue gas. This high-temperature flue gas heats the cold circulating water through the circulating water heat exchanger 9 to obtain hot water, which is then directed to the heat-consuming area. The used circulating water re-enters the circulating water heater through an external pipe, and this process is repeated.

[0042] The inner wall of ammonia cracking chamber 3 is coated with a Ni-based catalyst. This design utilizes the high intrinsic activity of nickel in breaking N–H bonds, thereby significantly reducing energy consumption and increasing single-pass conversion. Directly coating the catalyst onto the inner wall eliminates the need for additional support structures, allowing the heat of reaction to be rapidly replenished to the endothermic reaction through the metal wall, suppressing temperature drops. Simultaneously, the thin catalyst layer on the wall results in a low pressure drop, which is beneficial for system compactness and rapid start-up and shutdown. The Ni-based coating also reduces direct contact between ammonia in the gas phase and the metal wall, mitigating high-temperature nitriding corrosion and extending the life of the cracking chamber.

[0043] An ammonia flow meter 11 is installed on the pipeline between the ammonia storage tank 1 and the ammonia cracking chamber 3. This design allows for precise control of the ammonia flow rate. Furthermore, by adjusting the ammonia flow meter 11, the alcohol fuel flow meter 12, and the air flow meter 13, the ammonia cracked gas and methanol fuel can be burned at their respective optimal equivalence ratios, ensuring complete combustion of the fuel.

[0044] An alcohol fuel flow meter 12 is installed on the pipeline between the methanol storage tank 4 and the atomizing nozzle 8. This design allows for precise control of the methanol feed flow rate. Furthermore, by adjusting the ammonia flow meter 11, the methanol fuel flow meter 12, and the air flow meter 13, the ammonia cracked gas and methanol fuel can be burned at their respective optimal equivalence ratios, ensuring complete combustion of the fuel.

[0045] An air flow meter 13 is installed on the pipeline between the air blower 7 and the burner 51. This design allows for precise control of the air flow entering the burner 51. Furthermore, by adjusting the ammonia flow meter 11, the methanol fuel flow meter 12, and the air flow meter 13, the ammonia cracked gas and methanol fuel can be burned at their respective optimal equivalence ratios, ensuring complete combustion of the fuel.

[0046] Ball valves 14 and check valves 15 are installed on the pipeline between ammonia storage tank 1 and ammonia cracking chamber 3, as well as on the pipeline between methanol storage tank 4 and atomizing nozzle 8. Pressure reducing valve 2, ball valve 14, check valve 15, and ammonia flow meter 11 are arranged sequentially on the pipeline between ammonia storage tank 1 and ammonia cracking chamber 3.

[0047] A water pump 16 is connected to the outlet pipe of the circulating water heat exchanger 9. The hot water end of the circulating water heat exchanger 9 is connected to the heat user through the water pump 16, so as to facilitate the supply of heated water to the heat user.

[0048] The circulating water heat exchanger 9 forms a water circulation system with the heat users.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A methanol / ammonia integrated heating boiler, characterized in that: The system includes an ammonia storage tank (1), a pressure reducing valve (2), an ammonia cracking chamber (3), a methanol storage tank (4), a furnace body (5), a flue gas fan (6), and an air fan (7). The furnace body (5) contains a burner (51) and a heat exchange chamber (52). The air fan (7) is connected to the burner (51) via a pipeline. The ammonia storage tank (1), pressure reducing valve (2), ammonia cracking chamber (3), and burner (51) are connected sequentially via pipelines. An atomizing nozzle (8) is installed on the burner (51). The methanol storage tank (4) is connected to the atomizing nozzle (8) by a pipeline. The methanol fuel in the methanol storage tank (4) enters the burner (51) for combustion through the atomizing nozzle (8). A circulating water heat exchanger (9) is installed in the heat exchange chamber (52). An ammonia heater (10) is installed in the ammonia cracking chamber (3). The flue gas outlet of the heat exchange chamber (52), the flue gas fan (6) and the inlet of the ammonia heater (10) are connected in sequence by pipelines. The outlet of the ammonia heater (10) is connected to the outside air.

2. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: The inner wall of the ammonia cracking chamber (3) is coated with a Ni-based catalyst.

3. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: An ammonia flow meter (11) is installed on the pipeline between the ammonia storage tank (1) and the ammonia cracking chamber (3).

4. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: An alcohol fuel flow meter (12) is installed on the pipeline between the methanol storage tank (4) and the atomizing nozzle (8).

5. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: An air flow meter (13) is installed on the pipeline between the air fan (7) and the burner (51).

6. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: Ball valves (14) and check valves (15) are installed on the pipeline between the ammonia storage tank (1) and the ammonia cracking chamber (3) and on the pipeline between the methanol storage tank (4) and the atomizing nozzle (8).

7. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: A water pump (16) is connected to the outlet pipe of the circulating water heat exchanger (9).

8. The methanol / ammonia integrated heating boiler according to claim 1, characterized in that: The circulating water heat exchanger (9) forms a water circulation system with the heat users.

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