Centralized air separation nitrogen supply system for electric flame stove and working method

Abstract

The invention relates to the technical field of plasma electric flame stoves, in particular to a system for supplying nitrogen through centralized air separation for an electric flame stove and a working method. The system comprises an air compression and pretreatment unit, a pressure swing adsorption separation unit, a nitrogen buffer pressure stabilization unit, a nitrogen distribution conveying pipe network, a user side regulation and control unit and at least one electric flame stove which are sequentially connected in the gas flow direction. According to the invention, through centralized nitrogen generation and pipeline distribution, the problem of large-flow nitrogen supply of dispersed users is solved, and the emission of nitrogen oxides is greatly reduced due to the use of oxygen-free nitrogen by the electric flame stove. According to the system, indoor oxygen supplementation of oxygen-enriched gas and domestic hot water recovery of compressed waste heat are achieved at the same time, and the comprehensive utilization efficiency of resources is improved; by adopting the carbon steel pipe net, the construction cost is reduced, and nitrogen with different purities can be flexibly produced to meet multiple requirements; and real-time matching of nitrogen supply and stove power is realized through intelligent flow control of a user side, and stable and efficient operation is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of plasma electric flame stove technology, and in particular to a system and working method for centralized air separation and nitrogen supply for electric flame stoves. Background Technology

[0002] Plasma electric flame stoves, a new type of electrothermal conversion kitchen appliance, work by using a high-voltage circuit to excite a gaseous medium between specially designed electrodes (or "ion needles"), forming a stable high-temperature plasma arc (i.e., an "electric flame"). This directly heats the cookware, replacing traditional open flame or resistance heating methods. This technology directly converts electrical energy into heat energy, featuring high thermal efficiency, rapid response, and no need for fossil fuels. It is considered one of the potential technological pathways to replace gas stoves in residential, commercial, and even some industrial sectors, reducing dependence on imported natural gas.

[0003] Currently, electric flame stove technology has revealed significant technical bottlenecks in practical applications, especially when facing stringent indoor pollutant emission standards. The core issue lies in its working medium. Most existing electric flame stoves rely on built-in fans to draw in ambient air as the working medium for generating plasma. During high-voltage ionization, the local temperature of the electric flame is extremely high, exceeding 2000℃ according to research. At this extreme high temperature, nitrogen (N2) in the air is dissociated into reactive nitrogen atoms (N·), which then undergo a series of complex chemical reactions with oxygen (O2) or oxygen free radicals (O·), ultimately producing nitrogen oxides such as nitric oxide (NO) and nitrogen dioxide (NO2) (collectively referred to as NO). x This process is known as "thermal NO". x "The formation rate of NO increases exponentially with temperature. Therefore, electric flame stoves using air as the medium have a higher NO content." x Emission levels are often significantly higher than those of traditional gas stoves of the same power, which contradicts increasingly stringent indoor air quality and environmental protection requirements.

[0004] A direct solution to this pollution problem is to replace the working medium from oxygen-containing air with inert nitrogen. By producing nitrogen through on-site or nearby air separation devices and introducing it into the electric flame stove, the oxidant can be eliminated at its source, thus essentially suppressing the formation of thermal NOx. However, this solution faces significant challenges in implementation. To maintain a stable high-energy plasma flame, the electric flame stove requires a continuous supply of a large flow rate of gas (typically much higher than that used in laboratory or some industrial protective gas applications). Air separation equipment capable of meeting this flow rate requirement (such as nitrogen generators based on pressure swing adsorption or membrane separation technologies) is often large in size, consumes a lot of power, and generates noise during operation. For decentralized, small-scale residential users, such as apartment units, installing, operating, and maintaining such a system in each kitchen presents numerous obstacles, including large space requirements, high initial investment, poor operating economy, and a subpar user experience, making it impractical.

[0005] On the other hand, at the building or community level, centralized gas supply systems (such as central air conditioning and piped gas) have proven to be efficient, economical, and reliable solutions. However, current technologies have yet to design and implement a complete centralized nitrogen supply system specifically for electric flame stoves—a particular energy-consuming terminal—integrating air separation, nitrogen purification, pressure stabilization and buffering, long-distance safe delivery, precise user-end control, and comprehensive utilization of byproducts (such as oxygen and waste heat). In particular, key technical aspects such as balancing nitrogen purity (to meet the basic requirements of the stove while controlling costs), the material and safety requirements of the delivery pipeline, and intelligent flow control linked to the power of the user's stove still require systematic engineering solutions.

[0006] Therefore, there is an urgent need in this field for an innovative system and method that can supply sufficient nitrogen to numerous dispersed electric flame stove users in a centralized and modular manner in an economical, safe, and stable manner, while significantly reducing pollutant emissions, solving the technical and economic bottlenecks of single-household applications, and exploring the realization of cascaded comprehensive utilization of energy and resources. Summary of the Invention

[0007] The purpose of this invention is to address the lack of a complete centralized nitrogen supply system in the background technology that integrates air separation, nitrogen purification, pressure stabilization and buffering, long-distance safe transportation, precise control at the user end, and comprehensive utilization of by-products (such as oxygen and waste heat). This invention proposes a centralized air separation nitrogen supply system and its working method for electric flame stoves.

[0008] In a first aspect, the present invention provides a centralized air separation nitrogen supply system for an electric flame stove, the system comprising the following components connected sequentially along the gas flow direction:

[0009] The air compression and pretreatment unit is used to pressurize, cool, and purify the raw air.

[0010] The pressure swing adsorption separation unit has its inlet connected to the outlet of the air compression and pretreatment unit, and is used to separate the clean compressed air into nitrogen-rich gas and oxygen-rich gas.

[0011] A nitrogen buffer and pressure stabilizing unit has its inlet connected to the nitrogen-rich gas outlet of the pressure swing adsorption separation unit, and is used to store and stabilize the pressure of the nitrogen-rich gas.

[0012] A nitrogen distribution and delivery pipeline network, the input end of which is connected to the outlet of the nitrogen buffer and pressure stabilizing unit, is used to distribute and deliver the buffered and pressure-stabilized nitrogen to multiple dispersed gas consumption points.

[0013] User-end control units, located at each gas consumption point and connected to the corresponding branches of the nitrogen distribution and delivery pipeline network, are used to regulate the pressure and control the flow rate of the input nitrogen; and

[0014] At least one electric flame stove has its working medium inlet connected to the outlet of the user-end control unit, for receiving controlled nitrogen gas as a plasma forming medium to generate a high-temperature electric flame.

[0015] Optionally, the air compression and pretreatment unit includes an air compressor, an aftercooler, a filter, and a refrigerated dryer arranged sequentially along the air flow path; the air compressor is used to compress air to 0.6 MPa to 1.0 MPa; the aftercooler uses circulating cooling water to indirectly cool the compressed high-temperature air; the filter is used to remove solid particles and oil mist from the air; and the refrigerated dryer is used to cool the air to below its pressure dew point to deeply remove moisture.

[0016] Optionally, the pressure swing adsorption separation unit includes adsorption tank A and adsorption tank B arranged in parallel. Adsorption tank A and adsorption tank B are filled with carbon molecular sieve adsorbent, and the valves are controlled by a program to make each adsorption tower cycle through adsorption, pressure equalization, desorption and pressurization steps for continuous separation of oxygen and nitrogen.

[0017] Optionally, the nitrogen buffer and pressure stabilizing unit includes at least one nitrogen storage tank, which is equipped with a pressure detection instrument to smooth pressure fluctuations in the nitrogen output from the pressure swing adsorption separation unit and to provide a stable gas source for the nitrogen distribution and delivery pipeline network.

[0018] Optionally, the user-end control unit includes a pressure reducing valve and a flow controller connected in series. The flow controller responds to the power adjustment signal of the electric flame stove and dynamically adjusts the nitrogen volume flow rate supplied to the electric flame stove.

[0019] Optionally, the main pipelines and branch pipelines of the nitrogen distribution and delivery network are made of carbon steel.

[0020] Optionally, it also includes an oxygen-enriched gas utilization pipeline, one end of which is connected to the oxygen-enriched gas outlet of the pressure swing adsorption separation unit, and the other end leads to the living or working space inside the building, for providing oxygen-enriched air to improve the indoor environment.

[0021] Optionally, a heat recovery circuit is also included, which is connected to the cooling water outlet side of the aftercooler, for collecting hot water at 40°C to 50°C generated by cooling compressed air and guiding it to the domestic hot water system.

[0022] Optionally, a nitrogen refining and purification module is included, whose inlet end is connected to the nitrogen-rich gas outlet of the nitrogen buffer and stabilizing unit or the pressure swing adsorption separation unit, for producing nitrogen products with a purity higher than 99.5% for supply to other uses besides the electric flame stove.

[0023] Secondly, the present invention provides a method for using a centralized air separation nitrogen supply system for an electric flame stove, comprising the following steps:

[0024] Air pretreatment involves compressing, cooling, filtering, and drying the raw material air through the air compression and pretreatment unit to obtain process air with a pressure of 0.6 MPa to 1.0 MPa and dust and moisture content meeting the requirements.

[0025] Gas separation involves introducing the process air into the pressure swing adsorption separation unit, where nitrogen-rich gas and oxygen-rich gas are periodically separated by utilizing the kinetic adsorption effect of carbon molecular sieves.

[0026] Nitrogen buffer: The nitrogen-rich gas is delivered to the nitrogen buffer and pressure stabilization unit for storage and pressure stabilization.

[0027] Centralized distribution involves continuously delivering buffered and stabilized nitrogen to multiple gas consumption points distributed within the building via the nitrogen distribution and delivery pipeline network.

[0028] User-end control: At each gas consumption point, the received nitrogen gas is depressurized through the user-end control unit, and its supply flow is precisely controlled according to the firepower requirements of the corresponding electric flame stove.

[0029] The electric flame generation process involves introducing nitrogen gas, which has been depressurized and flow-controlled, into the electric flame stove as a working medium. The high-voltage ionization principle is used to generate a high-temperature plasma electric flame for cooking.

[0030] Optionally, in the user-end control, the power control signal of the electric flame stove is fed back to the flow controller of the user-end control unit to achieve closed-loop linkage matching between the nitrogen supply flow and the stove heating power; it also includes:

[0031] Oxygen recovery and utilization involves releasing the oxygen-enriched gas generated during the gas separation step into the indoor space via an independent pipeline to increase the oxygen concentration in the local environment.

[0032] Waste heat recovery involves collecting the low-temperature heat energy generated during the compressed air cooling stage of the air pretreatment step and using it to preheat domestic water.

[0033] Nitrogen gas is refined by diverting a portion of the nitrogen-rich gas and further purifying it to obtain high-purity nitrogen gas, which is used for preservation, cleaning, or inert protection processes in buildings.

[0034] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0035] By using centralized air separation to generate nitrogen and establishing a building-level distribution network, the technical bottleneck of being unable to obtain and store the large flow of nitrogen required by electric flame stoves at individual apartment buildings and other decentralized gas consumption points has been fundamentally solved, making it possible to use nitrogen as a cleaning working medium on a large scale.

[0036] By supplying oxygen-free nitrogen gas as the working medium to the electric flame stove, the oxidant is eliminated at the source of the reaction, effectively inhibiting the formation mechanism of thermal nitrogen oxides at high temperatures, so that the nitrogen oxide emission level of the electric flame stove can reach the same environmental protection standard as that of traditional gas stoves.

[0037] The oxygen-enriched gas generated during the air separation process is delivered to living or working spaces within the building through an independent pipeline system to increase the oxygen concentration in the local environment, which helps to improve indoor air quality.

[0038] By recovering the low-temperature heat energy (approximately 40-50℃ hot water) generated during the cooling process of compressed air and introducing it into the domestic hot water system, the cascade utilization of energy is achieved, reducing the overall energy consumption of the system.

[0039] Because the transport medium is inert nitrogen, the main and branch pipelines can be made of carbon steel, which has good pressure resistance and low cost, without the need to consider corrosion protection, thus reducing the material and construction costs of the pipeline network.

[0040] The system is flexibly configurable. While producing ordinary industrial nitrogen (e.g., 99.5% purity) to meet the needs of electric flame stoves, it can also produce high-purity nitrogen (e.g., 99.999% purity) through an additional refining module to supply other uses that may exist in the building (e.g., food preservation, electronic cleaning), thereby improving the overall efficiency of the system.

[0041] The flow control system at the user end can accurately and automatically adjust the nitrogen supply flow rate according to the real-time firepower (power) demand of the electric flame stove, ensuring stable combustion and optimal energy efficiency.

[0042] In summary, this invention solves the problem of high-flow nitrogen supply for dispersed users through centralized nitrogen production and pipeline distribution, and significantly reduces nitrogen oxide emissions from electric flame stoves by using oxygen-free nitrogen. The system also simultaneously achieves indoor oxygen replenishment with oxygen-enriched gas and recovery of domestic hot water from compressed waste heat, improving resource utilization efficiency. The use of carbon steel pipelines reduces construction costs and allows for flexible production of nitrogen of different purities to meet diverse needs. Intelligent flow control at the user end enables real-time matching of nitrogen supply and stove power, ensuring stable and efficient operation. Attached Figure Description

[0043] Figure 1 A schematic diagram of a centralized air separation nitrogen supply system for electric flame stoves;

[0044] Figure 2 A flowchart illustrating the working method of a centralized air separation nitrogen supply system for an electric flame stove.

[0045] Reference numerals: 1. Air compression and pretreatment unit; 2. Pressure swing adsorption separation unit; 3. Nitrogen buffer and stabilization unit; 4. Nitrogen distribution and delivery pipeline network; 5. User-end control unit; 6. Electric flame stove; 1-1. Air compressor; 1-2. Aftercooler; 1-3. Filter; 1-4. Refrigerated dryer; 2-1. Air process tank; 2-2. Adsorption tank A; 2-3. Adsorption tank B; 3-1. Nitrogen storage tank; 4-1. Delivery pipeline; 5-1. Pressure reducing valve; 5-2. Flow controller. Detailed Implementation

[0046] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0047] Example: Figure 1 and Figure 2 As shown, this invention provides a centralized air separation nitrogen supply system for electric flame stoves, typically arranged centrally in buildings, communities, or industrial parks. The system mainly comprises the following units connected sequentially and working collaboratively along the gas processing flow: air compression and pretreatment unit 1, pressure swing adsorption separation unit 2, nitrogen buffer and stabilization unit 3, nitrogen distribution and delivery pipeline network 4, user-end control unit 5, and electric flame stove 6. The specific structure, connection relationships, and functions of each unit are described in detail below.

[0048] In this embodiment, the air compression and pretreatment unit 1 is the front end of the system, responsible for processing ambient air into clean, dry compressed air that meets the requirements of subsequent separation processes. Figure 1 As shown, the unit includes, in sequence along the air flow direction, an air compressor 1-1, an aftercooler 1-2, a filter 1-3, and a refrigerated dryer 1-4.

[0049] The air compressor 1-1 is used to draw in ambient air and compress it to a predetermined pressure. In this embodiment, the air compressor compresses the air to a range of 0.6 MPa to 1.0 MPa (gauge pressure) to provide sufficient driving force for pressure swing adsorption separation.

[0050] Additionally, aftercooler 1-2 is connected to the outlet of air compressor 1-1. The compression process generates high temperatures (typically exceeding 100°C). Aftercooler 1-2 uses circulating cooling water to indirectly exchange heat with the high-temperature compressed air, initially cooling it to near room temperature (e.g., below 40°C), while simultaneously causing some water vapor to condense and precipitate. Preferably, a heat recovery loop can be installed to extract the hot water generated during this process at a temperature of approximately 40°C to 50°C and supply it to the building's domestic hot water system, thus realizing waste heat utilization.

[0051] Filters 1-3 receive pre-cooled air. Their main function is to remove solid and liquid particles such as dust, rust, and oil mist carried in the air, protecting downstream equipment. Precision filters are typically used.

[0052] In this embodiment, the freeze dryer 1-4 is connected after the filter 1-3. Its function is to further cool the air to below its pressure dew point temperature (e.g., 2°C to 10°C), causing most of the residual water vapor to condense into liquid water and be effectively separated and removed, thereby obtaining deeply dried compressed air. This is crucial for ensuring the long-term stable operation of the carbon molecular sieve adsorbent in the subsequent pressure swing adsorption unit.

[0053] After processing by this unit, the output is "process air" with stable pressure, clean and dry, which is then delivered to the pressure swing adsorption separation unit 2.

[0054] It is worth noting that the pressure swing adsorption separation unit 2 is the core of nitrogen production, and its inlet is connected to the outlet of the pretreatment unit 1. For example... Figure 1 As shown, the unit mainly includes an air process tank 2-1 and adsorption tanks A 2-2 and B 2-3 connected in parallel.

[0055] Among them, the air process tank 2-1 serves as a buffer container to smooth out airflow pulsations from the pretreatment unit, providing more stable air intake conditions for the subsequent adsorption tower.

[0056] Adsorption tanks A 2-2 and B 2-3 are two identical pressure vessels filled with carbon molecular sieve adsorbent. The adsorption kinetics of carbon molecular sieves differ for oxygen and nitrogen; under pressure, the adsorption rate for oxygen (as well as water and carbon dioxide) is much faster than for nitrogen. A valve group (not shown in detail in the diagram, but a conventional design in the field) controlled by a programmable logic controller (PLC) or distributed control system (DCS) allows the two adsorption towers to alternately cycle through the standard PSA process steps of "adsorption—pressure equalization—desorption—pressurization". When one tower (e.g., adsorption tank A) is in the high-pressure adsorption step, impurities such as oxygen in the process air are captured by the adsorbent, while nitrogen quickly passes through the adsorption bed and is produced from the top of the tower as "nitrogen-rich gas" (product gas). Simultaneously, the other tower (e.g., adsorption tank B) is in the low-pressure desorption step, desorbing the oxygen and other impurities adsorbed in the previous cycle and venting them, forming an "oxygen-rich flow". The two towers work alternately in this way, achieving continuous separation of oxygen and nitrogen.

[0057] Utilization of oxygen-enriched gas: The oxygen-enriched gas (with a significantly higher oxygen concentration than air) desorbed from the adsorption tower can be collected through independent pipelines and delivered to living spaces, offices, or public areas within buildings for release, thereby increasing the oxygen concentration in the local environment and helping to improve indoor air quality.

[0058] In this embodiment, the inlet of the nitrogen buffer and pressure stabilizing unit is connected to the nitrogen-rich gas outlet of the pressure swing adsorption separation unit 2. Its main component is at least one nitrogen storage tank 3-1. As a volumetric buffer container, the nitrogen storage tank 3-1 has two main functions: first, to store a certain amount of nitrogen to cope with changes in instantaneous flow rate demand at the point of use; and second, to smooth out minor fluctuations in product gas pressure and flow rate caused by periodic switching of the upstream PSA process. The storage tank is typically equipped with pressure gauges, pressure sensors, and other monitoring instruments to monitor the internal pressure and ensure a stable nitrogen source for the downstream pipeline network.

[0059] The input end of the nitrogen distribution and delivery pipeline network is connected to the outlet of the nitrogen buffer and pressure stabilizing unit 3. It consists of main pipelines, branch pipelines, and corresponding valves, covering the entire gas supply area (e.g., an entire building). In this embodiment, the delivery pipeline 4-1 serves as the main body of the network, responsible for transporting and distributing the centrally prepared nitrogen over long distances to various dispersed gas consumption points (e.g., individual kitchens). Since the delivery medium is chemically extremely stable inert nitrogen, and contains no moisture or corrosive components, the delivery pipelines (especially the main pipeline) can be made of low-cost, high-mechanical-strength carbon steel, eliminating concerns about corrosion and reducing construction costs while ensuring safety and pressure resistance.

[0060] In this embodiment, the user-end control unit 5 is installed at each gas consumption point (such as each household's kitchen), and its inlet is connected to the end of the corresponding branch of the nitrogen distribution and delivery pipeline network 4. Its main function is to perform final regulation of the high-pressure nitrogen entering the household to meet the specific needs of the electric flame stove 6. The user-end control unit 5 includes a pressure reducing valve 5-1 and a flow controller 5-2. The pressure reducing valve 5-1 reduces the higher-pressure nitrogen delivered from the pipeline network (e.g., still above 0.5 MPa) to the lower pressure (e.g., a few kPa to tens of kPa) required for the safe operation of the electric flame stove.

[0061] The flow controller 5-2 is connected in series after the pressure reducing valve 5-1. The flow controller 5-2 can be a flow meter with a regulating valve or an independent flow control valve. Its core function is to precisely control the volumetric flow rate of nitrogen supplied to the electric flame stove 6 based on its real-time firepower (power) requirements. For example, when the user increases the stove's power, the control system of the electric flame stove 6 will send a corresponding power increase signal. This signal is fed back to the flow controller 5-2, causing it to open wider and increase the nitrogen supply. This achieves a closed-loop linkage matching between the medium flow rate and the heating power, ensuring flame stability and optimal energy efficiency.

[0062] The working medium inlet of the electric flame stove 6 is connected to the outlet of the user-end control unit 5 via a hose or pipe. Nitrogen gas, after precise pressure control and flow regulation, enters the electric flame stove 6 as the working medium for generating a plasma arc (i.e., "electric flame"). Under the action of the high-voltage circuit of the electric flame stove, the nitrogen gas is ionized between specially designed electrodes (such as ion needles), forming a high-temperature plasma flame used to heat the cookware. Because the working medium is nitrogen gas that is almost free of oxygen (a purity of 99.5% is usually sufficient), the reaction source of nitrogen and oxygen combining at high temperatures to form thermal nitrogen oxides (NOx) is eliminated. x Therefore, the NO conditions for electric flame stoves using this nitrogen supply system are as follows: x Its emissions are extremely low, achieving environmental standards comparable to those of traditional natural gas stoves.

[0063] It is worth noting that this embodiment also includes a nitrogen purification module. Although the electric flame stove 6 can use ordinary industrial nitrogen (e.g., 99.5% purity), the system can be flexibly configured to produce higher purity nitrogen to meet other potential needs within the building. A nitrogen purification module (not shown in the figure, but can employ mature processes such as catalytic deoxygenation and deep adsorption) can be connected after the nitrogen buffer and stabilization unit 3 (or directly from the nitrogen-rich gas flow of the pressure swing adsorption separation unit 2). This module can purify a portion of the nitrogen to 99.999% or higher purity, producing "high-purity nitrogen." This high-purity nitrogen can be supplied through a separate small pipeline network to data centers (for equipment cooling and protection), laboratories, food storage rooms, and other places with special requirements within the building for cleaning electronic components, modified atmosphere storage of food, or creating an inert protective environment, achieving graded and efficient utilization of resources.

[0064] System working method process

[0065] Based on the above system, the working method of the centralized air separation nitrogen supply for electric flame stove of the present invention mainly includes the following steps:

[0066] Air pretreatment: Upon system startup, ambient air is compressed to 0.6–1.0 MPa by air compressor 1-1, and then sequentially cooled by aftercooler 1-2, impurities removed by filter 1-3, and deeply dried by freeze dryer 1-4 to obtain qualified process air. Simultaneously, waste heat generated by the aftercooler can be recovered.

[0067] Gas separation: Process air is fed into pressure swing adsorption (PSA) separation unit 2. By controlling adsorption tanks A 2-2 and B 2-3 to alternately perform adsorption and desorption operations, nitrogen-rich gas and oxygen-rich gas are continuously produced using the kinetic separation effect of carbon molecular sieves. The oxygen-rich gas can be directed into the indoor space for utilization.

[0068] Nitrogen buffer: The produced nitrogen-rich gas enters the nitrogen storage tank 3-1 of the nitrogen buffer and pressure stabilization unit 3 for storage and pressure stabilization.

[0069] Centralized distribution: Nitrogen gas under stable pressure is continuously delivered to various pre-set gas consumption points within the building via the main and branch pipelines of nitrogen distribution and delivery network 4.

[0070] User-side control: At each gas consumption point, the incoming nitrogen gas is first reduced to the appropriate pressure through the pressure reducing valve 5-1 of the user-side control unit 5. Then, the flow controller 5-2 precisely adjusts the nitrogen flow rate supplied to the stove based on the real-time operating power signal of the electric flame stove 6 at that point.

[0071] Electric flame generation: Nitrogen gas, after being depressurized and flow-controlled, enters the electric flame stove 6 and, as a plasma medium, generates a high-temperature electric flame under high-voltage ionization for cooking.

[0072] Nitrogen refining: Depending on the requirements, some nitrogen-rich gas can be introduced into the refining and purification module to produce high-purity nitrogen for other special purposes.

[0073] It is worth noting that this invention transforms the traditional decentralized electric flame stove system, which uses air as the working medium, into an intensive model with a central nitrogen generation unit supplying the gas. The system first pre-treats the air through multi-stage compression, cooling, filtration, and drying processes to remove moisture and particulate matter, creating stable raw material gas conditions for subsequent adsorption and separation. Then, utilizing the principle of the kinetic adsorption difference between oxygen and nitrogen under pressurized conditions using carbon molecular sieves, a pressure swing adsorption cycle with alternating adsorption towers continuously separates oxygen from the air, obtaining a nitrogen-rich gas stream dominated by nitrogen.

[0074] After being buffered and pressure-stabilized, nitrogen-rich gas is delivered to each user terminal through a dedicated pipeline network. The key mechanism lies in the fact that the transport medium is inert nitrogen, allowing for the use of low-cost carbon steel for the pipelines without corrosion concerns. Simultaneously, the pipeline pressure system can be optimized based on the characteristics of centralized gas supply. At the user end, the coordinated operation of a pressure reducing valve and a flow controller ensures the matching of the nitrogen supply pressure with the stove's required pressure. Furthermore, closed-loop regulation of the medium flow rate is implemented based on the real-time power feedback signal from the electric flame stove, thus ensuring the stability and controllability of the gas source during the electric flame generation process in principle.

[0075] The direct technical effect of this invention stems from a fundamental change in the working medium. Because the working medium of the electric flame stove is replaced by high-purity nitrogen instead of air containing approximately 21% oxygen, the basic conditions for the reaction of nitrogen and oxygen to generate thermal nitrogen oxides under high-temperature conditions are completely eliminated from a thermodynamic and kinetic perspective. Therefore, the nitrogen oxide emissions of the electric flame stove are significantly suppressed in principle, reaching emission levels comparable to traditional gas stoves. Simultaneously, the centralized gas supply mode solves the engineering problem at the system level of the difficulty for a single user to economically and efficiently obtain and store the large flow of nitrogen required by the electric flame stove. Furthermore, the oxygen-enriched gas and heat of compression naturally generated during system operation can serve as a supplementary oxygen source to improve indoor air quality and a low-temperature heat source for preheating domestic water, respectively, achieving tiered utilization of resources and energy. The system can also be expanded with a refining module to produce higher-purity nitrogen (e.g., 99.999%) while producing ordinary nitrogen (e.g., 99.5%) to meet the stove's requirements, for use in other processes within the building, thereby improving the system's overall efficiency and flexibility.

[0076] In summary, this invention effectively solves the bottleneck of large-flow nitrogen supply for dispersed users by constructing a centralized air separation and building-level pipeline distribution system, providing a feasible path for the large-scale application of nitrogen as a clean working medium. By supplying oxygen-free nitrogen to electric flame stoves, the generation of thermal nitrogen oxides is suppressed at the source of the reaction, enabling its emission levels to reach environmental standards comparable to those of traditional gas stoves. Simultaneously, the system achieves resource utilization of byproducts, including using the separated oxygen-enriched gas to improve indoor air quality and recovering compressed waste heat to supply domestic hot water, thus improving overall energy efficiency. In terms of system construction, because the transport medium is inert nitrogen, low-cost carbon steel pipes can be used, reducing pipeline investment and maintenance costs. The system also has flexible expansion capabilities, capable of simultaneously producing nitrogen of different purities to meet the diverse needs of stoves and other applications. Furthermore, through intelligent flow control at the user end, real-time matching of nitrogen supply and stove power is achieved, ensuring combustion stability and operational efficiency.

[0077] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A centralized air separation nitrogen supply system for electric flame stoves, characterized in that, The system comprises the following components connected sequentially along the gas flow direction: An air compression and pretreatment unit (1) is used to pressurize, cool and purify the raw material air; The pressure swing adsorption separation unit (2) has its inlet connected to the outlet of the air compression and pretreatment unit (1) and is used to separate the clean compressed air into nitrogen-rich gas and oxygen-rich gas. The nitrogen buffer and pressure stabilizing unit (3) has its inlet connected to the nitrogen-rich gas outlet of the pressure swing adsorption separation unit (2) and is used to store and stabilize the pressure of the nitrogen-rich gas. The nitrogen distribution and delivery pipeline (4) has its input end connected to the outlet of the nitrogen buffer and pressure stabilizing unit (3) for distributing and delivering the buffered and pressure-stabilized nitrogen to multiple dispersed gas consumption points. User-end control unit (5) is set at each gas consumption point and connected to the corresponding branch of the nitrogen distribution and delivery pipeline network (4) for pressure regulation and flow control of the input nitrogen. as well as At least one electric flame stove (6) has its working medium inlet connected to the outlet of the user-end control unit (5) for receiving controlled nitrogen as a plasma forming medium to generate a high-temperature electric flame.

2. The centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, The air compression and pretreatment unit (1) includes an air compressor (1-1), an aftercooler (1-2), a filter (1-3), and a freeze dryer (1-4) arranged sequentially along the air flow path; the air compressor (1-1) is used to compress air to 0.6 MPa to 1.0 MPa; the aftercooler (1-2) uses circulating cooling water to indirectly cool the compressed high-temperature air; the filter (1-3) is used to remove solid particles and oil mist from the air; and the freeze dryer (1-4) is used to cool the air to below its pressure dew point to deeply remove moisture.

3. The centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, The pressure swing adsorption separation unit (2) includes adsorption tank A (2-2) and adsorption tank B (2-3) arranged in parallel. Adsorption tank A (2-2) and adsorption tank B (2-3) are filled with carbon molecular sieve adsorbent. The valves are controlled by a program to make each adsorption tower cycle through adsorption, pressure equalization, desorption and pressurization steps for continuous separation of oxygen and nitrogen.

4. A centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, The nitrogen buffer and pressure stabilizing unit (3) includes at least one nitrogen storage tank (3-1). The nitrogen storage tank (3-1) is equipped with a pressure detection instrument to smooth the pressure fluctuation of the nitrogen output by the pressure swing adsorption separation unit (2) and to provide a stable gas source for the nitrogen distribution and delivery pipeline network (4).

5. A centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, The user-end control unit (5) includes a pressure reducing valve (5-1) and a flow controller (5-2) connected in series. The flow controller (5-2) responds to the power adjustment signal of the electric flame stove (6) and dynamically adjusts the nitrogen volume flow rate supplied to the electric flame stove (6).

6. A centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, It also includes an oxygen-enriched gas utilization pipeline, one end of which is connected to the oxygen-enriched gas outlet of the pressure swing adsorption separation unit (2), and the other end is connected to the living or working space in the building, for providing oxygen-enriched air to improve the indoor environment.

7. A centralized air separation nitrogen supply system for an electric flame stove according to claim 2, characterized in that, It also includes a heat recovery circuit, which is connected to the cooling water outlet side of the aftercooler (1-2) to collect hot water at 40°C to 50°C generated by cooling compressed air and guide it to the domestic hot water system.

8. A centralized air separation nitrogen supply system for an electric flame stove according to claim 1, characterized in that, It includes a nitrogen refining and purification module, whose inlet end is connected to the nitrogen-rich gas outlet of the nitrogen buffer and stabilizing unit (3) or the pressure swing adsorption separation unit (2), for producing nitrogen products with a purity higher than 99.5% for use other than the electric flame stove (6).

9. A method for using a centralized air separation nitrogen supply system as described in any one of claims 1 to 8 for use in an electric flame stove, characterized in that, Includes the following steps: Air pretreatment involves compressing, cooling, filtering, and drying the raw material air through the air compression and pretreatment unit (1) to obtain process air with a pressure of 0.6 MPa to 1.0 MPa and dust and moisture content meeting the requirements. Gas separation: The process air is introduced into the pressure swing adsorption separation unit (2), and nitrogen-rich gas and oxygen-rich gas are periodically separated by utilizing the kinetic adsorption effect of carbon molecular sieve. Nitrogen buffer: The nitrogen-rich gas is delivered to the nitrogen buffer and pressure stabilization unit (3) for storage and pressure stabilization; Centralized distribution, through the nitrogen distribution and delivery pipeline network (4), continuously delivers buffered and stabilized nitrogen to multiple gas consumption points distributed within the building; User-end control: At each gas consumption point, the received nitrogen gas is depressurized through the user-end control unit (5), and its supply flow is precisely controlled according to the firepower requirements of the corresponding electric flame stove (6). The electric flame is generated by passing nitrogen gas, which has been depressurized and flow controlled, into the electric flame stove (6) as the working medium. The high-temperature plasma electric flame for cooking is generated by using the high-voltage ionization principle. The medium used in the electric flame stove (6) does not contain oxygen, and the amount of thermal nitrogen oxides generated is very small. The nitrogen oxide content generated by the electric flame stove with nitrogen gas as the medium is very low, which can reach the emission index comparable to that of gas stoves.

10. The operating method of a centralized air separation nitrogen supply system for an electric flame stove according to claim 9, characterized in that, In the user-end control, the power control signal of the electric flame stove (6) is fed back to the flow controller (5-2) of the user-end control unit (5) to achieve closed-loop linkage matching between nitrogen supply flow and stove heating power; it also includes: Oxygen recovery and utilization involves releasing the oxygen-enriched gas generated during the gas separation step into the indoor space via an independent pipeline to increase the oxygen concentration in the local environment. Waste heat recovery involves collecting the low-temperature heat energy generated during the compressed air cooling stage of the air pretreatment step and using it to preheat domestic water. Nitrogen gas is refined by diverting a portion of the nitrogen-rich gas and further purifying it to obtain high-purity nitrogen gas, which is used for preservation, cleaning, or inert protection processes in buildings.

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