A high-efficiency denitration system based on liquid oxygen cold quantity recovery and ozone caching

Abstract

The utility model relates to the technical field of flue gas denitration, and specifically discloses an efficient denitration system based on liquid oxygen cold quantity recovery and ozone buffering, which comprises an oxygen supply system, an ozone generation and buffering system and an ozone dilution and reaction system. The ozone generation and buffering system comprises an ozone generator and an ozone buffering tank connected with the oxygen supply system in sequence. The ozone buffering tank is connected with the ozone dilution and reaction system and the input end of the ozone generator respectively. The oxygen supply system is connected with the ozone generator, the ozone buffering tank and the ozone dilution and reaction system respectively.

Description

Technical Field

[0001] This utility model relates to the field of flue gas denitrification technology, and more specifically, to a high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering. Background Technology

[0002] Ozone oxidation denitrification technology, as a novel flue gas purification process, is increasingly widely used in the field of nitrogen oxide treatment in industrial flue gas due to its advantages such as low reaction temperature window, no secondary pollution, and simple system. Its basic principle is to utilize the strong oxidizing properties of ozone to oxidize water-insoluble nitric oxide in flue gas into water-soluble nitrogen dioxide, dinitrogen pentoxide, and other higher-valence nitrogen oxides, which are then removed by alkaline absorbent liquid in an absorption tower (usually a desulfurization tower).

[0003] A conventional ozone oxidation denitrification system typically consists of an oxygen supply unit, an ozone generator, and an ozone dilution unit. The oxygen supply unit (such as liquid oxygen vaporization or on-site air separation oxygen generation) provides the oxygen source. The ozone generator converts the oxygen into ozone under a high-energy electric field. The generated ozone is mixed and diluted with compressed air introduced by the dilution fan before being injected into the flue to react with NOx.

[0004] However, existing conventional technologies have the following problems: (1) Ozone decomposition problem: Ozone is an unstable gas that spontaneously decomposes into oxygen at room temperature, and the decomposition rate increases sharply with increasing temperature. After the air is compressed by the dilution fan, it will generate a temperature rise of 10~15℃. When this part of hot air mixes with ozone, it will significantly increase the temperature of the mixed gas, accelerate the decomposition of ozone, and reduce the effective ozone concentration. In order to achieve the same denitrification efficiency, the ozone production must be increased, which will significantly increase the power consumption and cost of system operation.

[0005] (2) Energy waste problem: When liquid oxygen is used as the oxygen source, a large amount of high-quality low-temperature cold energy is released during the process of liquid oxygen vaporizing into room temperature oxygen (about -183°C to room temperature). In traditional processes, this part of high-quality cold energy is usually wasted by simply exchanging heat with the ambient air through the vaporizer and is not effectively utilized.

[0006] (3) System adjustment lag problem: The ozone generator power adjustment response is slow (usually 5-10 minutes), making it difficult to adapt to rapid fluctuations in flue gas load and NOx concentration. The lack of a buffer directly leads to poor system adjustment flexibility and insufficient ability to cope with peak loads.

[0007] To address the issue of high dilution air temperature, Chinese patent CN221999414U, entitled "An Oxidation Denitrification System for Improving Ozone Utilization," discloses the use of cooling water to lower the dilution air temperature. However, this method introduces additional water resources, water pumps, and chiller energy consumption, fails to fully utilize the system's own cooling source, is economically inefficient, and lacks a cooling and buffering mechanism for ozone itself. Furthermore, the problems of system regulation lag and insufficient peak handling capacity remain unresolved. Utility Model Content

[0008] The technical problem to be solved by this utility model is to provide a high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering. It makes full use of the low-temperature cold energy of liquid oxygen vaporization process to cool and dilute the air and store ozone, thereby inhibiting ozone decomposition. By setting up an ozone buffer tank, the system's adjustment response speed, operational stability and resistance to load fluctuations are improved, ultimately achieving the comprehensive goal of reducing operating costs, improving denitrification efficiency and system flexibility. The solution adopted by this utility model to solve the technical problem is: A highly efficient denitrification system based on liquid oxygen cold energy recovery and ozone buffering includes an oxygen supply system, an ozone generation and buffering system with cooling function, and an ozone dilution and reaction system with cooling function. The ozone generation and buffering system includes an ozone generator connected to an oxygen supply system and an ozone buffer tank connected to the ozone generator and having a cooling function; the ozone buffer tank is connected to an ozone dilution and reaction system. The oxygen supply system is connected to the ozone generator, the ozone buffer tank, and the ozone dilution and reaction system, respectively.

[0009] In some possible implementations, the ozone dilution and reaction system includes a mixer connected to an ozone buffer tank, an absorption tower connected to the mixer, and heat exchangers connected to the input terminals of the mixer and the ozone generator, respectively; the heat exchangers are connected to an oxygen supply system.

[0010] In some possible implementations, the ozone dilution and reaction system further includes a dilution fan connected to a heat exchanger.

[0011] In some possible implementations, the oxygen supply system includes a liquid oxygen storage tank and a vaporizer connected to the liquid oxygen storage tank and an ozone generator, respectively; the liquid oxygen storage tank is connected to an ozone buffer tank and a heat exchanger, respectively.

[0012] In some possible implementations, a pressure regulating device is provided between the vaporizer and the ozone generator for regulating the pressure of the gas entering the ozone generator.

[0013] In some possible implementations, a temperature sensor 2 is provided on the ozone buffer tank for monitoring its internal temperature; and a regulating valve 2 is provided on the pipeline connecting the oxygen supply system and the ozone buffer tank.

[0014] In some possible implementations, a temperature sensor is installed on the pipeline connecting the heat exchanger and the mixer to monitor the temperature of the compressed air entering the mixer after heat exchange, and a regulating valve is installed on the pipeline connecting the oxygen supply system and the heat exchanger.

[0015] In some possible implementations, the ozone buffer tank includes a housing that is connected to the ozone generator and the mixer respectively, and a cooling coil disposed within the housing; the oxygen supply system is connected to the inlet of the cooling coil, and the outlet of the cooling coil is connected to the input of the ozone generator.

[0016] The high-efficiency denitrification method based on the above-described high-efficiency denitrification system specifically includes the following steps: Step S1: The oxygen supply system delivers liquid oxygen in three separate streams to the ozone generator, the ozone buffer tank, and the heat exchanger in the ozone dilution and reaction system. The liquid oxygen entering the heat exchanger is vaporized after heat exchange and then enters the ozone generator. The liquid oxygen entering the ozone buffer tank is vaporized after heat exchange and then enters the ozone generator. The liquid oxygen entering the ozone generator is first vaporized into room temperature oxygen before entering the ozone generator. Step S2: The vaporized oxygen generates an ozone-oxygen mixture in the ozone generator, which then enters the ozone buffer tank; the mixture is cooled to a set temperature by the liquid oxygen in the ozone buffer tank and then stored. Step S3: The cooled ozone-oxygen mixture in the ozone buffer tank enters the mixer of the ozone dilution and reaction system and mixes with the compressed air delivered by the heat exchanger. The mixed gas is fully mixed and reacted with the flue gas delivered to the ozone dilution and reaction system.

[0017] In some possible implementations, the oxygen after vaporization in the three streams is pressure regulated before entering the ozone generator to achieve a pressure of 0.4 MPa; the temperature of the oxygen after vaporization in the three streams is 18-22°C.

[0018] In some possible implementations, the temperature of the compressed air entering the heat exchanger is 40-50°C; the temperature of the compressed air entering the mixer after heat exchange in the heat exchanger is 18-22°C.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention achieves efficient recovery and utilization of the cold energy of liquid oxygen for multiple materials (oxygen, compressed air, and ozone) within the same process system by diverting liquid oxygen to the cooling coils of the vaporizer, dilution air heat exchanger, and ozone buffer tank. This invention effectively realizes the recovery and utilization of liquid oxygen cold energy and the low-temperature storage and transportation of ozone. When the temperature of ozone and compressed air is reduced from 35℃ and 45℃ to 20℃ respectively, the amount of ozone decomposition can be reduced by about 90%. At the same time, an ozone buffer tank is set up to achieve an instant response to the supply of active molecules, shortening the response time to the 10-second level, which is 30 times faster than the direct adjustment of ozone generator (5-10 minutes). This invention achieves closed-loop automatic control of the dilution air temperature and ozone storage temperature by linking temperature sensors (temperature sensor one and temperature sensor two) with regulating valves (regulating valve one and regulating valve two), thereby realizing the on-demand allocation and optimized operation of the system cooling intensity. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the present invention; The components include: 1. Liquid oxygen storage tank; 2. Vaporizer; 3. Pressure regulating device; 4. Ozone generator; 5. Ozone buffer tank; 6. Mixer; 7. Absorption tower; 8. Dilution fan; 9. Heat exchanger; 10. Regulating valve one; 11. Temperature sensor one; 12. Temperature sensor two; 13. Regulating valve two. Detailed Implementation

[0021] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] The present invention will now be described in detail.

[0023] like Figure 1 As shown: A highly efficient denitrification system based on liquid oxygen cold energy recovery and ozone buffering includes an oxygen supply system, an ozone generation and buffering system with cooling function, and an ozone dilution and reaction system with cooling function. The ozone generation and buffering system includes an ozone generator 4 connected to the oxygen supply system and an ozone buffer tank 5 connected to the ozone generator 4 and having a cooling function; the ozone buffer tank 5 is connected to the ozone dilution and reaction system. The oxygen supply system is connected to the ozone generator 4, the ozone buffer tank 5, and the ozone dilution and reaction system respectively, realizing a three-way liquid oxygen supply.

[0024] Specifically, the oxygen supply system delivers liquid oxygen to the ozone generator 4, the ozone buffer tank 5, and the ozone dilution and reaction system; wherein: The liquid oxygen supplied to ozone generator 4 will first be vaporized to form room temperature oxygen at 18-22°C, and then enter the ozone generator 4. The liquid oxygen delivered to the ozone dilution and reaction system will exchange heat with the compressed air delivered to the ozone dilution and reaction system at a temperature of 45°C and vaporize to form room temperature oxygen at 18-22°C. The temperature of the compressed air after heat exchange is 18-22°C. The room temperature oxygen after heat exchange will be delivered to ozone generator 4. The liquid oxygen delivered to the ozone buffer tank 5 will exchange heat with the ozone in the ozone buffer tank 5 and vaporize to form room temperature oxygen at 18-22℃, which will then enter the ozone generator 4. The above three oxygen sources generate an ozone-oxygen mixture with a concentration of about 10wt% through dielectric barrier discharge in the ozone generator 4. The temperature of the ozone-oxygen mixture is about 35°C, and then it enters the ozone buffer tank 5. In the ozone buffer tank 5, the ozone-oxygen mixture is cooled to the set temperature by the liquid oxygen in the ozone buffer tank 5 and stored. The ozone buffer tank 5 plays a dual role of buffering and cooling.

[0025] The cooled ozone-oxygen mixture is drawn out from the ozone buffer tank 5 and mixed with compressed air from the ozone dilution and reaction system at a temperature of 18-22°C. The mixed gas is then injected into the flue gas duct in front of the desulfurization tower of the ozone dilution and reaction system to fully mix and react with the flue gas.

[0026] In some possible implementations, in order to enable the ozone buffer tank 5 to have both buffering and cooling functions, the ozone buffer tank 5 includes a housing that is respectively connected to the ozone generator 4 and the mixer 6, and a cooling coil disposed within the housing; the oxygen supply system is connected to the inlet of the cooling coil, and the outlet of the cooling coil is connected to the input end of the ozone generator 4.

[0027] Specifically, ozone generator 4 generates ozone-oxygen mixture at a temperature of approximately 35°C, which enters the housing for buffering and exchanges heat with liquid oxygen that directly enters the cooling coil through the oxygen supply system. The ozone buffer tank 5 buffers the ozone-oxygen mixture and cools it. The cooled ozone-oxygen mixture, with a temperature of 18-22°C, enters mixer 6 and mixes with compressed air at a temperature of 18-22°C after passing through heat exchanger 9.

[0028] In some possible implementations, in order to effectively exchange heat with the liquid oxygen entering the ozone dilution and reaction system through the oxygen supply system, and to mix the ozone-oxygen mixture with air, and to fully mix and react the final mixed gas with the flue gas; the ozone dilution and reaction system includes a mixer 6 connected to the ozone buffer tank 5, an absorption tower 7 connected to the mixer 6, and a heat exchanger 9 connected to the input terminals of the mixer 6 and the ozone generator 4 respectively; the heat exchanger 9 is connected to the oxygen supply system; the ozone dilution and reaction system also includes a dilution fan 8 connected to the heat exchanger 9.

[0029] Specifically, heat exchanger 9 is a shell-and-tube heat exchanger. Liquid oxygen enters the shell side of heat exchanger 9 and exchanges heat with compressed air at a temperature of about 45°C delivered by dilution fan 8 in the tube side of heat exchanger 9. After heat exchange, the compressed air at a temperature of 18-22°C will enter mixer 6 and mix with ozone-oxygen mixture delivered by ozone buffer tank 5 in mixer 6. Then it will be delivered to the flue gas duct before desulfurization in absorption tower 7 and mixed with the flue gas in the flue gas duct before entering the tower for full mixing reaction. The liquid oxygen after heat exchange will vaporize to form room temperature oxygen and enter ozone generator 4.

[0030] In some possible implementations, liquid oxygen is transported in three separate streams, and the liquid oxygen entering the ozone generator 4 is vaporized; the oxygen supply system includes a liquid oxygen storage tank 1 and a vaporizer 2 connected to the input terminals of the liquid oxygen storage tank 1 and the ozone generator 4 respectively; the liquid oxygen storage tank 1 is connected to the ozone buffer tank 5 and the heat exchanger 9 respectively.

[0031] Specifically, liquid oxygen storage tank 1 delivers a portion of liquid oxygen at a temperature of approximately -183°C to vaporizer 2, where it is vaporized into room temperature oxygen, which then enters ozone generator 4. Liquid oxygen storage tank 1 delivers a portion of liquid oxygen at a temperature of approximately -183°C directly to the shell side of heat exchanger 9 and the cooling coil of ozone buffer tank 5 for heat exchange. The ambient temperature oxygen formed after heat exchange is delivered to the input end of ozone generator 4 and combined with the ambient temperature oxygen formed after vaporization in vaporizer 2, and then processed in ozone generator 4.

[0032] In some possible implementations, in order to effectively adjust the pressure of the room temperature oxygen entering the ozone generator 4, a pressure regulating device 3 is provided between the vaporizer 2 and the ozone generator 4 to regulate the pressure of the gas entering the ozone generator 4; the pressure regulating device 3 stabilizes the pressure of the three oxygen streams at 0.4 MPa before sending it into the ozone generator 4.

[0033] In some possible implementations, in order to effectively control the temperature of the ozone-oxygen mixture stored in the ozone buffer tank 5 at around 20°C, a temperature sensor 212 for monitoring its internal temperature is provided on the ozone buffer tank 5; and a regulating valve 213 is provided on the pipeline connecting the oxygen supply system and the ozone buffer tank 5. During use, liquid oxygen flows in the cooling coil, absorbs heat from the ozone-oxygen mixture in the ozone buffer tank 5, and then vaporizes to form room temperature oxygen, which enters the ozone generator 4. The storage temperature of the ozone-oxygen mixture is controlled at around 20°C by temperature sensor 12 and regulating valve 13.

[0034] In some possible implementations, a temperature sensor 11 is provided on the pipeline connecting the heat exchanger 9 and the mixer 6 to monitor the temperature of the compressed air entering the mixer 6 after heat exchange, and a regulating valve 10 is provided on the pipeline connecting the oxygen supply system and the heat exchanger 9.

[0035] Specifically, liquid oxygen enters the heat exchanger 9 and exchanges heat with compressed air at a temperature of about 45°C delivered by the dilution fan 8. The liquid oxygen absorbs heat and vaporizes into room temperature oxygen, while the compressed air is cooled to 20±2°C. The temperature of the compressed air is monitored by a temperature sensor 11 and the opening of the regulating valve 10 is dynamically adjusted to precisely control the temperature.

[0036] The high-efficiency denitrification method based on the above-described high-efficiency denitrification system specifically includes the following steps: Step S1: Oxygen supply and cold energy recovery: The oxygen supply system delivers liquid oxygen at -183℃ to the ozone generator 4, the ozone buffer tank 5, and the heat exchanger 9 in the ozone dilution and reaction system via three separate routes. The liquid oxygen entering the heat exchanger 9 is vaporized after heat exchange to form room-temperature oxygen, which then enters the ozone generator 4. The liquid oxygen entering the ozone buffer tank 5 is vaporized after heat exchange to form room-temperature oxygen, which then enters the ozone generator 4. The liquid oxygen entering the ozone generator 4 is first vaporized by the oxygen supply system to form room-temperature oxygen before entering the ozone generator 4. Before entering the ozone generator 4, the three channels of ambient temperature oxygen are regulated by the pressure regulating device 3 to stabilize the pressure at 0.4MPa and then sent into the ozone generator 4. Step S2: Ozone generation and caching: The room-temperature oxygen after vaporization in the three channels generates an ozone-oxygen mixture at a temperature of about 35°C in the ozone generator 4, and then enters the ozone buffer tank 5. The ozone-oxygen mixture is cooled to the set temperature by liquid oxygen entering the cooling coil in the ozone buffer tank 5 and then stored. Step S3: Ozone dilution and reaction: The ozone-oxygen mixture cooled in the ozone buffer tank 5 enters the mixer 6 of the ozone dilution and reaction system and mixes with the compressed air delivered by the heat exchanger 9. The mixed gas is then fully mixed and reacted with the flue gas delivered to the ozone dilution and reaction system.

[0037] In some possible implementations, the temperature of the compressed air entering the heat exchanger 9 is 40-50°C; the temperature of the compressed air entering the mixer 6 after heat exchange in the heat exchanger 9 is 18-22°C.

[0038] This invention can effectively suppress ozone decomposition and improve denitrification efficiency: by cooling compressed air and ozone, it ensures that ozone is in a low-temperature environment throughout the entire process from ozone buffering, transportation to injection; by reducing the temperature of ozone and dilution air from 35℃ and 45℃ to 20℃ respectively, the ozone decomposition rate can be reduced by about 90%, thereby improving the effective ozone utilization rate and denitrification efficiency.

[0039] This invention converts the originally wasted liquid oxygen vaporization cold energy into a useful cooling source for cooling diluted air and ozone buffer tank 5, eliminating the need for cooling water, water pumps and power consumption of the chiller required by traditional water cooling systems, and reducing system operating costs.

[0040] This utility model system has a fast response speed and high adjustment flexibility: the ozone buffer tank 5 solves the problem of the ozone generator 4's response lag; the system response time is shortened from 5-10 minutes to 10 seconds, improving the response speed by 30 times, which can quickly adapt to the fluctuation of flue gas load and NOx concentration, and improve the system's adjustment flexibility and ability to cope with peak loads.

[0041] This invention is not limited to the specific embodiments described above. This invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering, characterized in that, This includes an oxygen supply system, an ozone generation and buffering system with cooling function, and an ozone dilution and reaction system with cooling function; The ozone generation and buffering system includes an ozone generator connected to an oxygen supply system and an ozone buffer tank connected to the ozone generator and having a cooling function; the ozone buffer tank is connected to an ozone dilution and reaction system. The oxygen supply system is connected to the ozone generator, the ozone buffer tank, and the ozone dilution and reaction system, respectively.

2. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 1, characterized in that, The ozone dilution and reaction system includes a mixer connected to an ozone buffer tank, an absorption tower connected to the mixer, and heat exchangers connected to the input ends of the mixer and the ozone generator, respectively; the heat exchangers are connected to an oxygen supply system.

3. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 2, characterized in that, The ozone dilution and reaction system also includes a dilution fan connected to the heat exchanger.

4. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 2, characterized in that, The oxygen supply system includes a liquid oxygen storage tank and a vaporizer connected to both the liquid oxygen storage tank and the ozone generator; the liquid oxygen storage tank is connected to an ozone buffer tank and a heat exchanger.

5. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 4, characterized in that, A pressure regulating device is provided between the vaporizer and the ozone generator to regulate the pressure of the gas entering the ozone generator.

6. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 4, characterized in that, A second temperature sensor is installed on the ozone buffer tank to monitor its internal temperature; a second regulating valve is installed on the pipeline connecting the oxygen supply system and the ozone buffer tank.

7. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 6, characterized in that, A temperature sensor is installed on the pipeline connecting the heat exchanger and the mixer to monitor the temperature of the compressed air entering the mixer after heat exchange; a regulating valve is installed on the pipeline connecting the oxygen supply system and the heat exchanger.

8. The high-efficiency denitrification system based on liquid oxygen cold energy recovery and ozone buffering according to claim 1, characterized in that, The ozone buffer tank includes a housing that is connected to an ozone generator and a mixer, respectively, and a cooling coil disposed within the housing; the oxygen supply system is connected to the inlet of the cooling coil, and the outlet of the cooling coil is connected to the inlet of the ozone generator.

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