Distributed heat supply device and method of condensation type ammonia gas and hydrogen mixed combustion boiler

Abstract

The invention relates to the technical field of energy, in particular to a distributed heat supply device and method of a condensation type ammonia gas and hydrogen mixed combustion boiler. According to the specific technical scheme, the distributed heat supply device of the condensation type ammonia gas and hydrogen mixed combustion boiler comprises a methanol hydrogen production system, the methanol hydrogen production system comprises a raw material supply unit, the raw material supply unit is communicated with a micro-reactor unit, the micro-reactor unit is communicated with a hydrogen purification unit, and the hydrogen purification unit is communicated with the methanol hydrogen production system. The hydrogen purification unit is respectively communicated with the hydrogen storage tank and the self-circulation heat supply module, and the self-circulation heat supply module is communicated with the raw material supply unit. The skid-mounted structure is adopted, the system equipment integration degree is high, the structure is compact, and transportation operation, popularization and application are convenient.

Description

Technical Field

[0001] The present invention relates to the field of energy technology, and in particular to a distributed heating device and method for a condensing ammonia and hydrogen mixed-firing boiler. Background Art

[0002] Hydrogen is a single substance formed by the element hydrogen, with the chemical formula H2 and a molecular weight of 2.01588. At room temperature and pressure, hydrogen is a colorless, tasteless, odorless, non-toxic, highly flammable, and insoluble gas in water. Its density is 0.089 g / L (101.325 kPa, 0°C), approximately 1 / 14 that of air, making it the lowest-density gas known. As an energy source, hydrogen has the following characteristics:

[0003] (l) Hydrogen is the lightest of all elements. Under standard conditions, its density is 0.0899 g / L. At -252.7°C, it becomes liquid. If the pressure is increased to hundreds of atmospheres, liquid hydrogen can become solid hydrogen.

[0004] (2) Among all gases, hydrogen has the best thermal conductivity, which is 10 times higher than that of most gases. Therefore, hydrogen is a good heat transfer carrier in the energy industry.

[0005] (3) Hydrogen is the most common element in nature. It is estimated to make up 75% of the mass of the universe. In addition to hydrogen in the air, it is mainly stored in the form of compounds in water, which is the most common substance on Earth. It is estimated that if all the hydrogen in seawater were extracted, the total heat it would produce would be 9,000 times greater than the heat released by all fossil fuels on Earth.

[0006] (4) Except for nuclear fuel, the calorific value of hydrogen is the highest among all fossil fuels, chemical fuels and biofuels, which is 142,351 kJ / kg, which is three times the calorific value of gasoline.

[0007] (5) Hydrogen has good combustion performance, ignites quickly, has a wide flammable range when mixed with air, and has a high ignition point and a fast burning speed.

[0008] (6) Hydrogen itself is non-toxic. Compared with other fuels, hydrogen burns the cleanest. In addition to producing water and a small amount of ammonia, it does not produce pollutants such as carbon monoxide, carbon dioxide, hydrocarbons, lead compounds and dust particles that are harmful to the environment. A small amount of ammonia will not pollute the environment after proper treatment. In addition, the water generated by combustion can continue to produce hydrogen and be recycled repeatedly.

[0009] (7) Hydrogen can be used in many ways. It can generate heat through combustion, produce mechanical work in heat engines, be used as an energy material in fuel cells, or be converted into solid hydrogen for use as a structural material. Replacing coal and oil with hydrogen does not require major modifications to existing technical equipment; existing internal combustion engines can be used with minimal modifications.

[0010] (8) Hydrogen can appear in the form of gaseous, liquid or solid hydrides, and can adapt to the different requirements of storage, transportation and various application environments.

[0011] Hydrogen is a readily available, green, low-carbon, and widely applicable secondary energy source. As carbon emissions from traditional fossil fuel boilers become increasingly prominent, hydrogen boilers, due to their zero-carbon emissions, have become an important alternative. However, issues such as high storage and transportation costs and poor safety have limited their large-scale application.

[0012] Ammonia (NH3), as a hydrogen energy carrier, offers advantages such as high volumetric energy density (liquid ammonia contains up to 17.6 wt% hydrogen), easy liquefaction (can be liquefied at -33°C or 0.8 MPa), and low transportation costs, making it an ideal medium for the indirect utilization of hydrogen energy. Ammonia is an inorganic compound with the chemical formula NH3 and a molecular weight of 17.031. Its density under standard conditions is 0.771 g / L, and its relative density is 0.5971 (air = 1.00). It is a colorless gas with a strong, pungent odor. Ammonia can turn moistened red litmus paper blue and produces a small amount of hydroxide ions in water, making it weakly alkaline. It can be liquefied under pressure at room temperature, has a boiling point of -33.5°C, and easily solidifies into a snow-like solid. Its melting point is -77.75°C, and it is soluble in water, ethanol, and ether. At high temperatures, it decomposes into nitrogen and hydrogen, which has a reducing effect. The chemical equation for combustion is: 4NH3+3O2→2N2+6H2OΔH=-1267kJ / mol

[0013] However, the flame propagation speed of ammonia is extremely low (about 0.1m / s), and pure ammonia has low combustion efficiency and is easy to extinguish. It needs to rely on hydrogen combustion to improve combustion performance. Traditional mixed burners have difficulty in achieving a uniform mixture of hydrogen, ammonia and air, resulting in local high temperature or unburned ammonia emissions. In addition, ammonia contains nitrogen, which easily generates NO during combustion. x When existing coal-fired boilers are mixed with ammonia, NO x Concentrations can be higher than with traditional fuels, requiring the use of complex denitrification systems (such as SCR / SNCR), which are costly and energy-intensive. Therefore, it is necessary to develop boiler equipment that can efficiently utilize zero-carbon fuels such as hydrogen and ammonia to reduce carbon emissions. Summary of the Invention

[0014] In view of the deficiencies in the prior art, the present invention provides a distributed heating device and method for a condensing ammonia and hydrogen co-firing boiler.

[0015] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0016] The present invention discloses a distributed heating device for a condensing ammonia and hydrogen co-firing boiler, comprising a methanol hydrogen production system, wherein the methanol hydrogen production system comprises a raw material supply unit, wherein the raw material supply unit is connected to a microreactor unit, wherein the microreactor unit is connected to a hydrogen purification unit, wherein the hydrogen purification unit is respectively connected to a hydrogen storage tank and a self-circulating heating module, and wherein the self-circulating heating module is connected to the raw material supply unit.

[0017] Preferably, the raw material supply unit includes a preheater and a superheater connected to the preheater, so that the mixture of methanol and deionized water passes through the preheater and the superheater in sequence to achieve vaporization pretreatment.

[0018] Preferably, the micro-reaction unit comprises a multi-stage serpentine micro-channel structure, and the micro-channel structure is filled with a noble metal composite catalyst.

[0019] Preferably, the width of the microchannel structure is 100-500 μm, and the noble metal composite catalyst is one or more of platinum-cerium oxide, platinum-indium oxide-aluminum oxide, and copper-zinc oxide-aluminum oxide catalysts.

[0020] Preferably, the hydrogen purification unit purifies the mixed gas by sequentially performing water washing, molecular sieve dehydration and CO2 adsorption.

[0021] Preferably, a heating system is further included, which includes a vertical boiler, the vertical boiler is respectively connected to a first heat exchanger, a second heat exchanger and the hydrogen storage tank, the first heat exchanger is sequentially connected to a water tank and a heat pump, the second heat exchanger is connected to a jet mixing device, the jet mixing device is respectively connected to an ammonia storage tank and a condensate spray storage tank, and the condensate spray storage tank is connected to an air storage tank; the combustion exhaust gas of the vertical boiler passes through the first heat exchanger, the second heat exchanger and the heat pump in sequence.

[0022] Preferably, a burner is provided in the vertical boiler, and the burner comprises a disk and a main shaft vertically arranged at the center of the disk, and a plurality of micro burners are arranged around the center of the disk.

[0023] Preferably, the micro burner includes a main air inlet pipe, a plurality of side air inlet pipes are arranged on the side wall of the main air inlet pipe, the connecting end of the main air inlet pipe and the disk surface is a tapered inner nozzle, and at the same time, an expansion-shaped outer nozzle connected to the inner nozzle is arranged on the disk surface, and an acceleration orifice plate is arranged in the main air inlet pipe.

[0024] Accordingly, a method for a distributed heating device utilizing a condensing ammonia and hydrogen co-firing boiler includes vaporizing and pre-treating a mixture of methanol and deionized water through the raw material supply unit, then reforming the methanol vapor through a microreactor unit to generate a mixed gas containing hydrogen, carbon dioxide, and carbon monoxide; purifying the mixed gas through a hydrogen purification unit and sending it to a hydrogen storage tank for storage; and then returning part of the purified hydrogen to the superheater and microreactor unit through a self-circulating heating module as a heat source for the reforming reaction.

[0025] The ammonia in the ammonia storage tank and the wet air in the air storage tank that has been humidified by the condensed water spray storage tank are mixed, and heat is exchanged with the combustion exhaust gas in the second heat exchanger. Then, the mixture enters the burner, is mixed with the hydrogen in the hydrogen storage tank in the micro burner, and is ejected and ignited after passing through the inner nozzle and the outer nozzle in sequence. The water is heated into high-temperature and high-pressure water vapor in the vertical boiler; the high-temperature combustion exhaust gas passes through the first heat exchanger, the second heat exchanger and the evaporator in the heat pump to heat the vertical boiler feed water, the mixture of ammonia and wet air and the heat pump working fluid. The combustion exhaust gas temperature drops to 60-80℃ and is discharged into the atmosphere. At the same time, the generated condensed water is collected in the condensed water spray storage tank for humidifying the air; after the heat pump working fluid absorbs heat and vaporizes in the evaporator, it is compressed into a high-temperature and high-pressure gaseous working fluid by the compressor, exchanges heat with cold water in the condenser, and supplies low-temperature hot water of 60-90℃.

[0026] Preferably, the mass ratio of methanol to deionized water is 1:1.5; the inlet temperature of the microreactor unit is controlled to be 200-350°C, and the space velocity is 800-1000h-1; and the volume ratio of ammonia to hydrogen is 1:0.2-5.

[0027] The present invention has the following beneficial effects:

[0028] 1. The distributed heating device of the condensing ammonia and hydrogen mixed-firing boiler adopts a skid-mounted structure. The system equipment has a high degree of integration and a compact structure, which is convenient for transportation, operation and promotion and application.

[0029] 2. Utilizing a composite precious metal catalyst and microreactor unit, this technology optimizes mass and heat transfer efficiency and increases active site utilization, achieving rapid mixing at micron to submillimeter scales, enabling efficient reactions. This results in a methanol conversion rate exceeding 96%, reducing production costs.

[0030] 3. The heating system uses zero-carbon emission hydrogen and ammonia as fuel. By adopting a new adjustable burner structure, it can adapt to the combustion requirements of different ratios of hydrogen and ammonia. At the same time, the physical and chemical properties of ammonia and hydrogen are fully considered. By adopting measures such as humidified air, premixed fuel, and ultra-high-speed flow, ammonia and hydrogen can be fully burned and the No x Generation.

[0031] 4. The condensing boiler is used to maximize the use of the sensible heat and latent heat in the water vapor generated by the combustion of ammonia and hydrogen, and the waste heat is reduced by the cascade utilization of the waste heat. loss and improve the utilization rate of waste heat.

[0032] 5. The distributed heating system of the condensing ammonia and hydrogen co-fired boiler can simultaneously produce high-temperature steam and hot water. In waste heat utilization, the flue gas passes through the heat pump's evaporator, where the water vapor in the flue gas condenses into liquid water. The working fluid in the evaporator absorbs the heat from the flue gas and evaporates. The working fluid then passes through the compressor and condenser to produce hot water at 60-90°C, achieving efficient energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic structural diagram of the heating system of the present invention;

[0034] Figure 2 Schematic diagram of the micro burner structure;

[0035] Figure 3 is a partial schematic diagram of the micro burner;

[0036] Figure 4 It is a schematic diagram of the disk;

[0037] In the figure: 1-water tank; 2-first heat exchanger; 3-boiler; 4-hydrogen storage tank; 5-second heat exchanger; 6-jet mixing device; 7-ammonia storage tank; 8-air storage tank; 9-condensate spray storage tank; 10-evaporator; 11-compressor; 12-throttle valve; 13-condenser; 14-disk; 15-main shaft; 16-main air inlet pipe; 17-side air inlet pipe; 18-inner nozzle; 19-outer nozzle; 20-acceleration orifice plate; fixing hole 21, insulation cover 22, igniter 23, pipeline support 24, side pipe support 25, annular gas distributor 26. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0040] refer to Figure 1-Figure 4This invention discloses a distributed heating system for a condensing ammonia and hydrogen co-firing boiler, comprising a methanol hydrogen production system and a heating system. The two systems are integrated into a skid-mounted structure with a compact design, with the methanol hydrogen production system and heating system housed in two containers.

[0041] Specifically: the methanol hydrogen production system includes a raw material supply unit, which includes a preheater and a superheater connected to the preheater, so that a mixture of methanol and deionized water passes through the preheater and the superheater in sequence to achieve vaporization pretreatment, and the mass ratio of the methanol to deionized water is 1:1.5.

[0042] The raw material supply unit is connected to the microreactor unit, and the microreactor unit includes a multi-stage serpentine microchannel structure. The width of the microchannel structure is 100-500μm. The microchannel structure is filled with a precious metal composite catalyst, and the precious metal composite catalyst is one or more of platinum-cerium oxide (Pt / CeO2), platinum-indium oxide-alumina (Pt / In2O3 / Al2O3), and copper-zinc oxide-alumina catalyst (Cu / ZnO / Al2O3). The reaction temperature is 240-300°C and the pressure is from normal pressure to 5MPa, which is used to realize the methanol steam reforming reaction and generate a mixed gas containing hydrogen, carbon dioxide and carbon monoxide. At the same time, the inlet temperature of the microchannel structure is controlled to 200-350°C and the space velocity is 800-1000h -1 , methanol conversion rate ≥96%.

[0043] The micro-reaction unit is connected to the hydrogen purification unit, and the hydrogen purification unit is connected to the hydrogen storage tank 4. The hydrogen purification unit purifies the mixed gas through water washing, molecular sieve dehydration and CO2 adsorption in sequence, purifying it to a hydrogen purity of ≥99.9% and sending it to the hydrogen storage tank.

[0044] The hydrogen purification unit is connected to the self-circulating heating module, which is in turn connected to the raw material supply unit. The self-circulating heating module returns part of the purified hydrogen to the superheater and microreactor unit as a heat source for the reforming reaction.

[0045] Furthermore, the heating system includes a vertical boiler 3, which is respectively connected to a first heat exchanger 2, a second heat exchanger 5 and the hydrogen storage tank 4, the first heat exchanger 2 is sequentially connected to a water tank 1 and a condenser 13 on a heat pump, the second heat exchanger 5 is connected to a jet mixing device 6, and the jet mixing device 6 is respectively connected to an ammonia storage tank 7 and a condensed water spray storage tank 9, and the condensed water spray storage tank 9 is connected to an air storage tank 8; the combustion exhaust gas of the vertical boiler 3 passes through the first heat exchanger 2, the second heat exchanger 5 and the evaporator 10 on the heat pump in sequence.

[0046] For further reference, Figure 2 、 3 As shown, a burner is provided in the vertical boiler 3, and the burner includes a disk 14 and a main shaft 15 vertically arranged at the center of the disk 14. The main shaft is tubular, and the disk can be cylindrical with an axial through hole at its center. The main shaft 15 and the disk can be fixed by screws. The disk 14 is evenly provided with a plurality of micro burners around its center. Specifically: the side wall of the main shaft 15 is provided with a plurality of fixing holes 21 along its axial direction. The main shaft is fixed through the fixing holes and the disk by screws, which are used to adjust the relative position of the disk and the main shaft. The position of the disk can be adjusted according to different fuel ratios, and then the nozzle shape of the micro burner can be adjusted to achieve good combustion of the fuel. A heat-insulating cover plate 22 is provided at the connecting end of the main shaft and the disk to protect the structure inside the main shaft. The cover plate is connected to the main shaft by bolts. When the position of the disk needs to be adjusted, the heat-insulating cover plate needs to be removed.

[0047] As one of the implementation methods, Figure 2 For example, the fixed holes are numbered ①, ②, and ③ from left to right. When the disk is fixed to hole ①, the inner and outer nozzles fit tightly together and form a convergence-divergence nozzle, which is suitable for low hydrogen blending ratio (≤20%) working conditions. It can better mix hydrogen, ammonia and air to achieve good combustion of the mixture. When the disk is fixed to holes ② and ③, there will be a gap between the inner and outer nozzles, which serve as a return air channel for the combustion exhaust gas. The combination is a convergence-divergence nozzle with return air, which is suitable for working conditions with medium and high hydrogen blending ratios (20%-500%). The return air channel can mix the combustion exhaust gas (hydrogen will generate water after combustion, and the exhaust gas will contain a large amount of water vapor) into the fuel, which can further reduce the combustion temperature of the hydrogen-rich mixed fuel and reduce NO x Generation.

[0048] For further reference, Figure 2 As shown, the micro burner includes a main air intake pipe 16, and a plurality of side air intake pipes 17 are provided on the side wall of the main air intake pipe 16. The connecting end of the main air intake pipe 16 and the disk surface 14 is a tapered inner nozzle 18. At the same time, an expansion-shaped outer nozzle 19 connected to the inner nozzle 18 is provided on the disk surface 14, and an igniter 23 is provided at the open end of the outer nozzle. An acceleration orifice plate 20 is provided in the main air intake pipe 16.

[0049] Furthermore, the outer wall of the main shaft 15 is provided with a pipe support 25 for supporting the main air intake pipe 16, and a plurality of side pipe supports 25 are provided between the side air intake pipe 17 and the main air intake pipe 16, thereby ensuring the stability of the main air intake pipe and the side air intake pipe.

[0050] Furthermore, the inlet ends of all the side air inlet pipes are commonly connected to an annular gas distributor 26, which can simultaneously introduce hydrogen into the side air inlet pipes.

[0051] Furthermore, the heat pump includes an evaporator 10 and a compressor 11 , a throttle valve 12 and a condenser 13 connected in series with the evaporator 10 .

[0052] The present invention also discloses a method for a distributed heating device based on the above-mentioned condensing ammonia and hydrogen mixed-firing boiler, wherein the specific hydrogen production process of the methanol hydrogen production system is as follows:

[0053] The raw material supply unit pre-treats the methanol and deionized water mixture by vaporization, and then reforms the methanol vapor through the microreactor unit to generate a mixed gas containing hydrogen, carbon dioxide, and carbon monoxide; the mixed gas is purified by the hydrogen purification unit and sent to the hydrogen storage tank 4 for storage; and then, a portion of the purified hydrogen is returned to the superheater and the microreactor unit through the self-circulating heating module as a heat source for the reforming reaction;

[0054] The specific process of the heating system is:

[0055] The ammonia in the ammonia storage tank 7 and the wet air in the air storage tank 8 that has been humidified by the condensed water spray storage tank 9 are mixed to form a mixture called gas 1, and the fuel equivalence ratio (the ratio of the actual amount of air supplied to the amount of air required for complete combustion) is 0.8-1.2; the mixture 1 exchanges heat with the combustion exhaust gas in the second heat exchanger 5, and then the mixture 1 is pressurized and enters the burner, and is mixed with the hydrogen in the hydrogen storage tank 4 in the micro burner to form a mixture called gas 2, and the volume ratio of ammonia to hydrogen is 1:0.2-5, and is accelerated by the inner nozzle 18 and the outer nozzle 19 in turn and then ejected and ignited, in the vertical The water in the boiler 3 is heated to high-temperature and high-pressure water vapor; the high-temperature combustion exhaust gas passes through the first heat exchanger 2, the second heat exchanger 5 and the evaporator 10 in the heat pump to heat the vertical boiler 3 feed water, ammonia and humid air mixture (mixed gas 1) and the heat pump working fluid. The combustion exhaust gas temperature drops to 60-80°C and is discharged into the atmosphere. At the same time, the generated condensed water is collected in the condensed water spray storage tank 9 and used to humidify the air; finally, the heat pump working fluid absorbs heat and vaporizes in the evaporator 10, and is compressed into a high-temperature and high-pressure gaseous working fluid by the compressor 11. It exchanges heat with cold water in the condenser 13 to supply low-temperature hot water at 60-90°C.

[0056] Furthermore, once the mixed gas is pressurized, it flows into the main intake pipe 16 and forms multiple high-speed airflows through the accelerating orifice plate 20. The high-speed airflow flows through the side air inlet to form a negative pressure zone, and hydrogen flows from the side air inlet 17 through the side air inlet into the main intake pipe 16. Taking advantage of the strong diffusivity of hydrogen, hydrogen can quickly mix with the mixed gas one to form the mixed gas two. Subsequently, the mixed gas two flows through the tapered inner nozzle 18 for further acceleration and mixing, and then passes through the expanding outer nozzle 19 to achieve ultra-high-speed flow. The high-speed flow of the fuel gas flow can not only make the combustion flame of hydrogen more stable and promote the stable combustion of ammonia, but also can make the fuel and air evenly mixed, further promote the stable combustion of ammonia, and can prevent the local combustion temperature from being too high to generate a large amount of NO. x At the same time, multiple flames can increase the heat exchange efficiency.

[0057] The distributed heating device disclosed in the present invention realizes the cascade utilization of the waste heat of combustion exhaust (including the latent heat of water vapor) by burning zero-carbon fuel, and can simultaneously supply high-temperature steam, low-temperature hot water, and collect condensed water, greatly improving energy utilization efficiency.

[0058] The present invention will be further described below with reference to specific embodiments.

[0059] Example 1

[0060] A distributed heating system for a condensing ammonia and hydrogen co-firing boiler, including a methanol hydrogen production system and a heating system. The system is integrated into two containers and adopts a skid-mounted structure.

[0061] 1. Methanol hydrogen production system

[0062] Raw material supply unit: Methanol and deionized water are mixed in a mass ratio of 1:1.5, heated to 80°C in a preheater, and then enter a superheater to be heated to 200°C to complete vaporization pretreatment.

[0063] Microreactor unit: adopts a multi-stage serpentine microchannel structure with a channel width of 300μm and is filled with platinum-cerium oxide catalyst (Pt / CeO2). The reaction temperature is 280℃, the pressure is 3MPa, and the space velocity is 900h -1 After the methanol steam reforming reaction, a mixed gas containing hydrogen (H2, about 75%), carbon dioxide (CO2, about 23%) and carbon monoxide (CO, about 2%) is generated, and the methanol conversion rate reaches 97%.

[0064] Hydrogen purification unit: The mixed gas passes through a water scrubber to remove soluble impurities, and then enters a CO2 adsorption device (using activated carbon-based adsorbent) after dehydration by a molecular sieve. The final hydrogen purity is ≥99.9% and is stored in a hydrogen storage tank 4.

[0065] Self-circulating heating module: 10% of the purified hydrogen is returned to the superheater and microreactor unit, and hydrogen combustion is used to provide a heat source for the reforming reaction, realizing energy self-circulation.

[0066] 2. Heating system

[0067] Fuel mixing and combustion process:

[0068] The air is passed from the air storage tank 8 into the condensed water spray storage tank 9 for humidification to form wet air (humidity 60%), which is mixed with the ammonia output from the ammonia storage tank 7 in a volume ratio of 1:0.5 to form a mixed gas.

[0069] After being preheated to 150°C in the second heat exchanger 5, the gas mixture is pressurized to 0.5 MPa by a booster pump and enters the micro-burner's main intake pipe 16. The high-speed airflow passes through the acceleration orifice 20 to form multiple jets, creating a negative pressure at the side intake port. Hydrogen from the hydrogen storage tank 4 is drawn into the main intake pipe 16 through this jet (or through the side intake pipe 17), where it rapidly mixes with the gas mixture 1 to form the gas mixture 2 (ammonia to hydrogen volume ratio of 1:0.3).

[0070] The mixed gas flows through the converging inner nozzle 18 (throat diameter 2mm) and is accelerated to 50m / s. It then flows through the expanding outer nozzle 19 (exit diameter 5mm) to form an ultra-high-speed flow (80m / s) and ignites and burns in the micro-burner. The flame is evenly sprayed into the combustion chamber of the vertical boiler 3 through 12 circumferentially distributed micro-burners. The combustion temperature is controlled at 1100℃, effectively suppressing the generation of NOx (emission concentration <50mg / m 3 ).

[0071] Waste heat cascade utilization process:

[0072] The high-temperature flue gas (initial temperature 800°C) generated by combustion flows through the first heat exchanger and the second heat exchanger in sequence, heating the boiler feed water (supplied from water tank 1) and the mixed gas 1 respectively, and the flue gas temperature drops to 200°C.

[0073] The remaining flue gas enters the evaporator 10 of the heat pump and exchanges heat with the heat pump working medium (R134a). The flue gas temperature is further reduced to 70°C and then discharged into the atmosphere. At the same time, the condensed water is collected in the condensed water spray storage tank 9 for recycling.

[0074] After absorbing heat and vaporizing in the evaporator 10, the heat pump working fluid is pressurized to 1.2 MPa by the compressor 11, enters the condenser 13 to exchange heat with cold water, and outputs 85°C low-temperature hot water for use by the user.

[0075] 3. Key structural parameters

[0076] The burner of the vertical boiler 3 adopts an adjustable disk structure. The main shaft adjusts the axial distance between the disk and the main shaft through the fixed hole (adjustment range ±5mm) to adapt to different fuel ratios (ammonia to hydrogen volume ratio 1:0.2~5).

[0077] The jet mixing device 6 adopts a venturi tube design, and the mixing efficiency is ≥95%.

[0078] The heat pump system has a COP of 3.8 and can simultaneously supply high-temperature steam (pressure 1.6 MPa, temperature 250°C) and low-temperature hot water (85°C).

[0079] 4. Implementation Effect

[0080] The overall thermal efficiency of the system reaches 92%, which is 25% higher than that of traditional boilers;

[0081] NOx emission concentration in combustion exhaust gas is less than 50mg / m 3 , no additional denitrification equipment is required;

[0082] Condensate recovery rate>90%, realizing water resource recycling;

[0083] The skid-mounted design shortens the installation period to 48 hours and is suitable for distributed heating scenarios.

[0084] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, 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 cannot be understood as a limitation on the present invention.

[0085] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler, characterized by: The invention comprises a methanol hydrogen production system, wherein the methanol hydrogen production system comprises a raw material supply unit, the raw material supply unit is connected to a microreactor unit, the microreactor unit is connected to a hydrogen purification unit, the hydrogen purification unit is respectively connected to a hydrogen storage tank (4) and a self-circulating heating module, and the self-circulating heating module is connected to the raw material supply unit.

2. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 1, characterized in that: The raw material supply unit includes a preheater and a superheater connected to the preheater, so that the mixed liquid of methanol and deionized water passes through the preheater and the superheater in sequence to achieve vaporization pretreatment.

3. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 1, characterized in that: The micro-reaction unit comprises a multi-stage serpentine micro-channel structure, and the micro-channel structure is filled with a noble metal composite catalyst.

4. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 3, characterized in that: The width of the microchannel structure is 100-500 μm, and the noble metal composite catalyst is one or more of platinum-cerium oxide, platinum-indium oxide-aluminum oxide, and copper-zinc oxide-aluminum oxide catalysts.

5. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 1, characterized in that: The hydrogen purification unit purifies the mixed gas through water washing, molecular sieve dehydration and CO2 adsorption in sequence.

6. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 1, characterized in that: The invention also includes a heat supply system, which includes a vertical boiler (3), the vertical boiler (3) is respectively connected to a first heat exchanger (2), a second heat exchanger (5) and the hydrogen storage tank (4), the first heat exchanger (2) is sequentially connected to a water tank (1) and a heat pump, the second heat exchanger (5) is connected to a jet mixing device (6), the jet mixing device (6) is respectively connected to an ammonia storage tank (7) and a condensed water spray storage tank (9), and the condensed water spray storage tank (9) is connected to an air storage tank (8); the combustion exhaust gas of the vertical boiler (3) passes through the first heat exchanger (2), the second heat exchanger (5) and the heat pump in sequence.

7. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 6, characterized in that: A burner is provided in the vertical boiler (3), and the burner comprises a disk (14) and a main shaft (15) vertically arranged at the center of the disk (14). The disk (14) is provided with a plurality of micro burners around its center.

8. The distributed heating device for a condensing ammonia and hydrogen mixed-firing boiler according to claim 7, characterized in that: The micro-burner comprises a main air inlet pipe (16), a plurality of side air inlet pipes (17) are arranged on the side wall of the main air inlet pipe (16), a connection end between the main air inlet pipe (16) and the disk surface (14) is a tapered inner nozzle (18), and an expanding outer nozzle (19) in communication with the inner nozzle (18) is arranged on the disk surface (14), and an acceleration orifice plate (20) is arranged in the main air inlet pipe (16).

9. A method for a distributed heating device using the condensing ammonia and hydrogen mixed-firing boiler according to any one of claims 1 to 8, characterized in that: The raw material supply unit is used to pre-treat the mixture of methanol and deionized water by vaporization, and then the methanol water vapor is reformed by the microreactor unit to generate a mixed gas containing hydrogen, carbon dioxide and carbon monoxide; the mixed gas is purified by the hydrogen purification unit and sent to the hydrogen storage tank (4) for storage; and the partially purified hydrogen is returned to the superheater and the microreactor unit through the self-circulating heat supply module to serve as a heat source for the reforming reaction; The ammonia in the ammonia storage tank (7) and the wet air in the air storage tank (8) that has been humidified by the condensed water spray storage tank (9) are mixed, and heat exchanged with the combustion exhaust gas in the second heat exchanger (5). Then, the ammonia enters the burner, and is mixed with the hydrogen in the hydrogen storage tank (4) in the micro burner. After passing through the inner nozzle (18) and the outer nozzle (19) in sequence, the ammonia is sprayed out and ignited. In the vertical boiler (3), water is heated to high-temperature and high-pressure steam. The high-temperature combustion exhaust gas passes through the first heat exchanger (2), the second heat exchanger (3), and the hydrogen in the hydrogen storage tank (4) is ignited. The evaporator (10) in the heat pump and the radiator (5) heat the feed water of the vertical boiler (3), the mixed gas of ammonia and moist air and the heat pump working fluid, and the combustion tail gas temperature is reduced to 60-80°C and discharged into the atmosphere. At the same time, the generated condensed water is collected in the condensed water spray storage tank (9) and used to humidify the air. After the heat pump working fluid absorbs heat and vaporizes in the evaporator (10), it is compressed into a high-temperature and high-pressure gaseous working fluid by the compressor (11), and heat is exchanged with cold water in the condenser (13) to supply low-temperature hot water of 60-90°C.

10. The distributed heating method for a condensing ammonia and hydrogen mixed-firing boiler according to claim 9, characterized in that: The mass ratio of methanol to deionized water is 1:1.5; the inlet temperature of the microreactor unit is controlled at 200-350° C., and the space velocity is 800-1000 h -1 ; and the volume ratio of ammonia to hydrogen is 1:0.2-5.

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