CN-121990528-A - System for centralized air separation and nitrogen supply for electric flame stove and working method

CN121990528ACN 121990528 ACN121990528 ACN 121990528ACN-121990528-A

Abstract

The invention relates to the technical field of plasma electric flame stoves, in particular to a system for supplying nitrogen to an electric flame stove through centralized air separation and a working method thereof. The system comprises an air compression and pretreatment unit, a pressure swing adsorption separation unit, a nitrogen buffer voltage stabilization unit, a nitrogen distribution and conveying pipe network, a user side regulation unit and at least one electric flame stove which are sequentially connected along the gas flow direction. The invention solves the problem of large-flow nitrogen supply of dispersed users by centralizing nitrogen production and pipeline distribution, and greatly reduces the emission of nitrogen oxides due to the use of anaerobic nitrogen in the electric flame stove. The system simultaneously realizes the indoor oxygen supplementation of oxygen-enriched gas and the recovery of domestic hot water by compressed waste heat, improves the comprehensive utilization efficiency of resources, reduces the construction cost by adopting a carbon steel pipe network, can flexibly produce nitrogen with different purity to meet multiple requirements, realizes the real-time matching of nitrogen supply and stove power by intelligent flow control of a user side, and ensures stable and efficient operation.

Inventors

SONG YAWEI
LIU CHENGZHOU
Wu Dianwu
FENG HANSHENG
LUO GUANGNAN
LIN QIFU
CHEN LONGWEI
LI ZHENYANG
CHEN WEIYE
LI WEI
XU QIANG
XIA WENXIANG
WANG JIAYI

Assignees

合肥综合性国家科学中心能源研究院(安徽省能源实验室)

Dates

Publication Date: 20260508
Application Date: 20260306

Claims (10)

1. A system for centralized air separation for supplying nitrogen to an electric flame burner, the system comprising, in succession along the direction of the gas flow: The air compression and pretreatment unit (1) is used for pressurizing, cooling and purifying raw material air; the pressure swing adsorption separation unit (2) is connected with the air inlet of the air compression and pretreatment unit (1) and is used for separating the clean compressed air into nitrogen-rich gas and oxygen-rich gas; the nitrogen buffer pressure stabilizing unit (3) is connected with a nitrogen-rich gas outlet of the pressure swing adsorption separation unit (2) at an air inlet and is used for storing and stabilizing the pressure of the nitrogen-rich gas; the input end of the nitrogen distribution and conveying pipe network (4) is connected with the air outlet of the nitrogen buffer pressure stabilizing unit (3) and is used for distributing and conveying the nitrogen after buffer pressure stabilization to a plurality of dispersed air utilization points; a user end regulating unit (5) arranged at each gas utilization point and connected with the corresponding branch of the nitrogen distribution and delivery pipe network (4) for carrying out pressure regulation and flow control on the input nitrogen, and And the working medium inlet of the at least one electric flame stove (6) is connected with the outlet of the user side regulating unit (5) and is used for receiving the regulated nitrogen as a plasma forming medium to generate high-temperature electric flame.
2. The system for the electric flame stove by utilizing the centralized air separation and nitrogen supply according to claim 1 is characterized in that the air compression and pretreatment unit (1) comprises an air compressor (1-1), an aftercooler (1-2), a filter (1-3) and a freeze dryer (1-4) which are sequentially arranged along an air flow path, wherein the air compressor (1-1) is used for compressing air to 0.6-1.0 MPa, the aftercooler (1-2) is used for indirectly cooling compressed high-temperature air by adopting circulating cooling water, the filter (1-3) is used for removing solid particles and oil mist in the air, and the freeze dryer (1-4) is used for cooling the air below a pressure dew point of the air to deeply remove water.
3. The system for centralized air-separation nitrogen supply for electric flame stoves according to claim 1, wherein the pressure swing adsorption separation unit (2) comprises an adsorption tank a (2-2) and an adsorption tank B (2-3) which are arranged in parallel, carbon molecular sieve adsorbents are filled in the adsorption tank a (2-2) and the adsorption tank B (2-3), and each adsorption tower is circulated to perform adsorption, pressure equalization, desorption and pressurization steps through a program control valve for continuous separation of oxygen and nitrogen.
4. The system for centralized air separation and nitrogen supply for electric flame stoves according to claim 1, wherein the nitrogen buffer pressure stabilizing unit (3) comprises at least one nitrogen storage tank (3-1), and a pressure detecting instrument is arranged on the nitrogen storage tank (3-1) and is used for smoothing pressure fluctuation of nitrogen output by the pressure swing adsorption separation unit (2) and providing a stable air source for the nitrogen distribution conveying pipe network (4).
5. A centralized air-separation nitrogen-supply system for an electric flame burner as claimed in claim 1, wherein the user-side regulating unit (5) comprises a pressure-reducing valve (5-1) and a flow controller (5-2) arranged in series, the flow controller (5-2) being responsive to a power-regulating signal of the electric flame burner (6) to dynamically adjust the volumetric flow of nitrogen gas supplied to the electric flame burner (6).
6. A system for centralized air-separation nitrogen supply for electric flame stoves according to claim 1, characterized in that it further comprises an oxygen-enriched gas utilization line, one end of which is connected to the oxygen-enriched gas outlet of the pressure swing adsorption separation unit (2), and the other end of which opens into the living or working space within the building for providing oxygen-enriched air to improve the indoor environment.
7. A system for centralized air-separation nitrogen supply for electric flame stoves according to claim 2, characterized in that it further comprises a heat recovery circuit, which communicates with the cooling water outlet side of the aftercooler (1-2), for collecting the hot water of 40-50 ℃ generated by cooling the compressed air and directing it to the domestic hot water system.
8. A system for centralized air-separation nitrogen supply for electric flame stoves according to claim 1, characterized in that it comprises a nitrogen refining purification module, the inlet end of which is connected to the nitrogen-rich gas outlet of the nitrogen buffer pressure stabilizing unit (3) or the pressure swing adsorption separation unit (2), for producing nitrogen products with purity higher than 99.5%, for other uses than the electric flame stoves (6).
9. A method of operation of a centralized air separation nitrogen supply for an electric flame burner employing the system of any of claims 1 to 8, comprising the steps of: air pretreatment, namely compressing, cooling, filtering and drying raw material air through the air compression and pretreatment unit (1) to obtain process air with the pressure of 0.6-1.0 MPa and the dust content and the water content meeting the requirements; gas separation, introducing the process air into the pressure swing adsorption separation unit (2), and periodically separating nitrogen-rich gas and oxygen-rich gas by utilizing the dynamic adsorption effect of a carbon molecular sieve; Nitrogen buffering, namely conveying the nitrogen-rich gas to the nitrogen buffering and pressure stabilizing unit (3) for storage and pressure stabilization; the concentrated delivery is carried out, and the buffered and stabilized nitrogen is continuously delivered to a plurality of gas utilization points distributed in a building through the nitrogen distribution delivery pipe network (4); The user end regulates and controls, at each gas point, the pressure reduction treatment is carried out on the received nitrogen through the user end regulating and controlling unit (5), and the supply flow of the nitrogen is accurately controlled according to the fire power demand of the corresponding electric flame stove (6); The electric flame is generated, nitrogen gas which is subjected to pressure reduction and flow control is used as a working medium to be introduced into the electric flame stove (6), high-temperature plasma electric flame for cooking is generated by utilizing a high-voltage ionization principle, the medium used by the electric flame stove (6) does not contain oxygen, the thermal nitrogen oxide generation amount is small, the nitrogen gas is used as the medium to generate the nitrogen oxide generated by the electric flame stove of the electric flame, the content of the nitrogen oxide generated by the electric flame stove is low, and the emission index equivalent to that of the gas stove can be achieved.
10. The method according to claim 9, wherein in the user side regulation, the power control signal of the electric flame stove (6) is fed back to the flow controller (5-2) of the user side regulation unit (5) to realize closed loop linkage matching of the nitrogen supply flow and the stove heating power, further comprising: oxygen is recycled, and oxygen-enriched gas generated in the gas separation step is led to an indoor space for release through an independent pipeline so as to improve the oxygen concentration of a local environment; Waste heat recovery, namely collecting low-temperature heat energy generated in a compressed air cooling stage in the air pretreatment step and preheating domestic water; and (3) refining nitrogen, namely, diverting a part of nitrogen-enriched gas, and further purifying to obtain high-purity nitrogen for the fresh-keeping, cleaning or inert protection process in the building.

Description

System for centralized air separation and nitrogen supply for electric flame stove and working method Technical Field The invention relates to the technical field of plasma electric flame stoves, in particular to a system for supplying nitrogen to an electric flame stove through centralized air separation and a working method thereof. Background The plasma electric flame stove is used as a novel electric heating conversion kitchen ware, and the working principle is that a gas medium is excited between special electrodes (or called 'ion needles') through a high-voltage circuit to form a stable high-temperature plasma arc (namely 'electric flame'), so that the kitchen ware is directly heated in place of the traditional open flame or resistance heating mode. The technology directly converts electric energy into heat energy, has the characteristics of high heat efficiency, rapid response, no need of fossil fuel and the like, and is considered as one of potential technical paths for replacing gas cookers and reducing the external dependence of natural gas in the fields of residents, businesses and even partial industries. At present, the electric flame stove technology exposes a remarkable technical bottleneck in actual popularization, especially when facing to strict indoor pollutant emission standards. The core problem is its working medium. Most of the existing electric flame stove products rely on an internal fan to suck ambient air as a working medium for generating plasma. During high voltage ionization, the local temperature of the electric flame is extremely high, and research shows that the electric flame can exceed 2000 ℃. At this extremely high temperature, nitrogen (N 2) in the air is dissociated into reactive nitrogen atoms (N. Cndot.) and undergoes a complex series of chemical reactions with oxygen (O 2) or oxygen radicals (O. Cndot.) also originating from the air, ultimately producing nitrogen oxides (collectively referred to as NO x) such as Nitric Oxide (NO) and nitrogen dioxide (NO 2). This process is known as "thermal NO x" generation, whose rate of generation increases exponentially with temperature. Thus, electric flame stoves using air media tend to have significantly higher NO x emissions than conventional gas stoves of the same power, which is contrary to increasingly stringent indoor air quality and environmental requirements. A straightforward solution to this contamination problem is to replace the working medium with inert nitrogen by oxygen-containing air. The oxidizing agent can be radically eliminated by preparing nitrogen gas through an on-site or nearby air separation device and introducing the nitrogen gas into an electric flame stove, so that the generation of thermal NOx is basically inhibited. However, this approach presents serious challenges at an implementation level. To maintain a stable high energy plasma flame, an electric flame burner requires a continuous supply of a relatively large flow of gaseous medium (typically much higher than in laboratory or certain industrial shielding gas applications). Air separation equipment (such as nitrogen generators based on pressure swing adsorption or membrane separation techniques) capable of meeting such flow requirements tend to be bulky, consume high power, and produce some noise during operation. For a distributed small-scale family user represented by an apartment unit, a set of equipment which is independently installed, operated and maintained in each kitchen has many barriers such as large space occupation, high initial investment, poor operation economy, poor user experience and the like, and the equipment has no practical feasibility. On the other hand, at the building or community level, centralized gas supply systems (e.g. central air conditioning, pipeline gas) have proven to be efficient, economical and reliable solutions. However, in the prior art, a complete centralized nitrogen supply system integrating air separation, nitrogen purification, voltage stabilization and buffering, long-distance safe transportation, accurate regulation and control at a user side and comprehensive utilization of byproducts (such as oxygen and waste heat) is not designed and realized aiming at a specific energy utilization terminal of an electric flame stove. In particular, how to balance the key technical links of nitrogen purity (to meet the basic requirements of a kitchen range and control the cost), the material and safety requirements of a conveying pipe network, intelligent flow control linked with the power of a user kitchen range and the like, a systematic engineering scheme still needs to be proposed. Therefore, there is a need in the art for an innovative system and method that can economically, safely and stably supply sufficient nitrogen to numerous dispersed electric flame stove users in a building in a centralized and modularized manner, and that can solve the technical and economic bottlenecks of single-user application w