Gaseous nitrous acid generation device and generation method

Abstract

The application discloses a gaseous nitrous acid generating device and a generating method, which comprise a constant temperature control unit, a gas tank, a nitrite mixed solution tank, an atomizing nozzle, a gas cylinder and a detection unit. The constant temperature control unit is provided with the gas tank, the nitrite mixed solution tank and the atomizing nozzle. The input end of the atomizing nozzle is communicated with the nitrite mixed solution tank, and the spraying end is communicated with the gas tank. The atomizing nozzle is used for spraying the nitrite mixed solution in the nitrite mixed solution tank into the gas tank in a mist state. The gas tank is provided with an air inlet and an air outlet. The output end of the gas cylinder is communicated with the air inlet and the air outlet and then communicated with the detection unit. The application has the advantages that the customized glassware is cancelled, the generating device is simplified, the cost is reduced, the nitrite mixed solution is atomized by the atomizing nozzle, the gaseous nitrous acid is dispersed in the gas tank, and the output efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical material preparation technology, specifically to a gaseous nitrous acid generator and a generation method. Background Technology

[0002] In recent years, gaseous nitrous acid has gradually become a research hotspot in atmospheric chemistry. Gaseous nitrous acid accumulates at night and undergoes photolysis during the day. This photolysis generates a large number of OH free radicals, which significantly enhance atmospheric oxidation, making it an important trace pollutant. Research on the measurement, inversion, and reaction mechanisms of gaseous nitrous acid relies heavily on stable, reliable, and high-purity sources.

[0003] Because gaseous nitrous acid is a weak acid with low solubility, it is often prepared by reacting nitrite solutions with dilute acids in a light-protected and low-temperature environment. However, gaseous nitrous acid is highly reactive, adsorbing and reacting on many surfaces, and is easily decomposed by temperature and light. Therefore, conventional gas preparation methods, such as diffusion tubes and permeation tubes, are difficult to apply to the preparation of gaseous nitrous acid. Initially, researchers used the equilibrium of NO, NO2, and water vapor at room temperature to generate gaseous nitrous acid (e.g., Chinese invention patent document CN117699750A) or by thermally decomposing ammonium nitrite. However, these two methods could not achieve stable production and had low purity. Currently, the mainstream methods for preparing gaseous nitrous acid include bubbling, gas-solid reactions, and interfacial reactions. The bubbling method involves introducing high-purity nitrogen gas into a device such as a spiral tube to produce a mixed solution of nitrite and dilute acid, resulting in gaseous nitrite in the bubbled gas (e.g., Chinese invention patent document CN104986745A). Gas-solid reactions include reacting sublimated oxalic acid vapor with solid NaNO2, purging heated and stirred NaNO2 powder with gaseous hydrochloric acid (e.g., Chinese invention patent document CN107228923A), and producing gaseous nitrite by coating a tube with NO2 containing 3% 2,2-adiazon-bis(3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt (ABTS) solution. Interfacial reactions involve reacting water vapor and NO at a high-temperature stainless steel interface to generate gaseous nitrite, which is then cooled and carried out by a carrier gas.

[0004] Existing technologies for preparing gaseous nitrous acid face several key bottlenecks: Firstly, the equipment is complex, often involving customized glassware (such as spiral tubes and reflux tubes), leading to inherent problems of equipment fragility and inconvenient transportation. Although the reaction rate for obtaining gaseous nitrous acid via gas-phase reaction increases at high temperatures, it also accelerates the decomposition of gaseous nitrous acid, thus affecting the stability of the yield. Secondly, the complex gas path design exacerbates adsorption losses of gaseous nitrous acid during transport, and the overall process requires significant manual intervention and has low automation, resulting in poor operational repeatability and low gas production efficiency. Furthermore, while existing methods have gradually improved gas purity and stability, they generally suffer from inflexible concentration adjustment, low reactant utilization, and high experimental costs, severely restricting practical applications. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to improve the production efficiency of gaseous nitrous acid and reduce its cost.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A gaseous nitrous acid generator includes a constant temperature control unit, a gas pool, a nitrite mixed solution pool, an atomizing nozzle, a gas cylinder, and a detection unit. The constant temperature control unit is equipped with the gas pool, the nitrite mixed solution pool, and the atomizing nozzle. The input end of the atomizing nozzle is connected to the nitrite mixed solution pool, and the spray end is connected to the gas pool. The atomizing nozzle is used to spray the nitrite mixed solution in the nitrite mixed solution pool into the gas pool in a mist form. The gas pool is equipped with an air inlet and an air outlet. The output end of the gas cylinder is connected to the air inlet and the air outlet, and then connected to the detection unit.

[0008] This invention eliminates the need for customized glassware, simplifies the generating device, reduces costs, and improves production efficiency by atomizing the nitrite mixture solution through atomizing nozzles to disperse gaseous nitrite in the gas pool. It can flexibly and easily provide specific concentrations of gaseous nitrite and provides reliable support for concentration detection, thus providing effective technical support for the source analysis, generation mechanism, and atmospheric chemical behavior research of gaseous nitrite.

[0009] Preferably, the output end of the gas cylinder is connected to the inlet, outlet and detection unit via a gas pipeline.

[0010] Preferably, a first flow control valve is provided on the air inlet.

[0011] Preferably, a second flow control valve is installed on the gas pipeline between the air inlet and the air outlet.

[0012] Preferably, the gas outlet is also connected to the residual solution collection bottle.

[0013] Preferably, the air inlet and air outlet are located at opposite ends of the air pool.

[0014] Preferably, the solution height in the nitrite mixed solution tank is not higher than the nozzle tip height of the atomizing nozzle.

[0015] Preferably, optical windows are provided at both ends of the gas pool.

[0016] Preferably, the temperature control unit is a constant temperature water bath.

[0017] The present invention also provides a method for generating gaseous nitrous acid using a gaseous nitrous acid generator, specifically comprising the following steps: S1: The temperature control unit is kept at the design temperature. The atomizing nozzle is turned on to spray the nitrite mixed solution in the nitrite mixed solution tank into the gas tank in a mist form. S2: Open the gas cylinder. The gas inside the cylinder is divided into two paths. One path, the carrier gas, enters the gas pool through the inlet, accelerating the diffusion of the mist-like nitrite mixed solution in the gas pool into the gas phase, promoting the evaporation and uniform dispersion of nitrite droplets. The other path, the dilution gas, directly mixes with the gaseous nitrite discharged from the outlet and enters the detection unit to obtain the required concentration of gaseous nitrite.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention eliminates the need for customized glassware, simplifies the generating device, reduces costs, and improves production efficiency by atomizing the nitrite mixture solution through atomizing nozzles to disperse gaseous nitrite in the gas pool. It can flexibly and easily provide specific concentrations of gaseous nitrite and provides reliable support for concentration detection, thus providing effective technical support for the source analysis, generation mechanism, and atmospheric chemical behavior research of gaseous nitrite. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of an embodiment of the present invention; Figure 3 This is a schematic diagram of the installation structure of the atomizing nozzle according to an embodiment of the present invention. Detailed Implementation

[0020] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0021] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "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 mechanical connection, an electrical connection, or a communication connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] In this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited.

[0023] See Figures 1 to 3 This embodiment discloses a gaseous nitrous acid generator, including a constant temperature control unit 1, a gas pool 2, a nitrite mixed solution pool 3, an atomizing nozzle 4, a gas cylinder 5, and a detection unit 6.

[0024] In this embodiment, the constant temperature control unit 1 is a constant temperature water bath. The constant temperature control unit 1 is equipped with an air tank 2, a nitrite mixed solution tank 3, and multiple atomizing nozzles 4 arranged at equal intervals. The tank temperature is set to 0°C to reduce the decomposition rate of nitrite.

[0025] The nitrite mixed solution pool 3 contains a nitrite mixed solution prepared with a certain concentration of dilute, non-oxidizing acids (such as hydrochloric acid and dilute sulfuric acid) and sodium nitrite.

[0026] In this embodiment, the atomizing nozzle 4 is an ultrasonic spray nozzle. The input end of the atomizing nozzle 4 is connected to the nitrite mixed solution pool 3, and the spray end is connected to the gas pool 2. The atomizing nozzle 4 is used to spray the nitrite mixed solution in the nitrite mixed solution pool 3 into the gas pool 2 in a mist form. The two ends of the gas pool 2 are respectively provided with an air inlet 201 and an air outlet 202. The output end of the gas cylinder 5 extends into the constant temperature control unit 1 through the gas pipe 7 and is connected to the air inlet 201 and the air outlet 202, and then connected to the detection unit 6. The atomizing nozzle 4 atomizes the nitrite mixed solution into fine droplets, which are evenly spaced at the bottom of the gas pool 2 to improve the uniformity of droplet distribution and increase the contact area between the carrier gas and the nitrite mixed solution. The carrier gas entering through the air inlet 201 is used to accelerate the diffusion of nitrite in the droplets into the gas phase and further promote the evaporation and uniform dispersion of the nitrite droplets. The gas in the gas cylinder 5 is high-purity nitrogen or zero air.

[0027] Furthermore, according to the principle of communicating vessels, the height of the nitrite mixed solution added to the nitrite mixed solution pool 3 is not higher than the nozzle end height of the atomizing nozzle 4. At this time, the liquid will not enter the gas pool 2 and can maintain a relatively reasonable atomization efficiency.

[0028] A first flow control valve 8 is provided on the air inlet 201, and a second flow control valve 9 is provided on the gas pipeline 7 between the air inlet 201 and the air outlet 202. The air outlet 202 is also connected to the residual solution collection bottle 10 for collecting residual solution droplets flowing out from the air outlet 202.

[0029] Furthermore, optical windows 11 are respectively provided at both ends of the gas cell 2 for qualitative or quantitative testing of the generated gaseous nitrous acid. The transmission range of the optical window 11 should not include the wavelength range that easily decomposes nitrous acid.

[0030] Furthermore, the inner walls of the gas tank 2, the atomizing nozzle 4, and the optical window 11 are coated with materials that reduce nitrous acid adsorption, such as silanes and fluorinated alkanes. The gas tank 2 is made of glass, quartz, or polytetrafluoroethylene, with a volume of 100 mL to 10 L, and is made or coated with opaque materials to reduce the HONO decomposition rate; the first flow control valve 8 and the second flow control valve 9 have corrosion resistance and low adsorption performance, with a flow rate of 1 mL / min to 500 mL / min.

[0031] See Figure 2 The detection unit 6 is a NOx analyzer or a HONO analyzer. The HONO analyzer can be a chemical ionization mass spectrometer (CIMS) or a long path absorption spectrometer (LOPAP), which can be selected according to the concentration of HONO generated by the standard generation system.

[0032] This embodiment also discloses a method for generating gaseous nitrous acid using a gaseous nitrous acid generator, which specifically includes the following steps: S1: The temperature control unit 1 is kept at the design temperature. In this embodiment, the temperature control unit 1 is adjusted to about 0°C and kept for a period of time until the temperature field of the device no longer changes significantly. Then, the nitrite mixed solution is placed in the nitrite mixed solution pool 3, and the solution height is not higher than the nozzle end height of the atomizing nozzle 4. Then, the atomizing nozzle 4 is turned on to spray the nitrite mixed solution in the nitrite mixed solution pool 3 into the gas pool 2 in a mist. S2: Open gas cylinder 5. The gas inside cylinder 5 is divided into two streams. One stream is carrier gas, which enters gas pool 2 through inlet 201, accelerating the diffusion of the mist-like nitrite mixed solution in gas pool 2 into the gas phase, promoting the evaporation and uniform dispersion of nitrite droplets. The other stream is dilution gas, which directly mixes with the gaseous nitrite discharged from outlet 202 and enters detection unit 6 to obtain the desired concentration of gaseous nitrite. Specifically, after the carrier gas enters gas pool 2, the generated gaseous nitrite is qualitatively detected through optical window 11, and the gas flow rate is controlled by the first flow control valve 8 and the second flow control valve 9. After the airflow stabilizes, the gaseous nitrite discharged from outlet 202 mixes with the gaseous nitrite and enters detection unit 6 to obtain the desired concentration of gaseous nitrite.

[0033] In this embodiment, the customized glassware is eliminated, simplifying the generating device and reducing costs. Furthermore, by atomizing the nitrite mixture solution through the atomizing nozzle 4, the gaseous nitrite is dispersed in the gas pool 2, thereby improving production efficiency. This allows for the flexible and convenient provision of specific concentrations of gaseous nitrite and provides reliable support for concentration detection. It also provides effective technical support for the analysis of the source of gaseous nitrite, its generation mechanism, and its atmospheric chemical behavior.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0035] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A gaseous nitrous acid generator, characterized in that: It includes a constant temperature control unit, a gas pool, a nitrite mixed solution pool, an atomizing nozzle, a gas cylinder, and a detection unit. The constant temperature control unit is equipped with a gas pool, a nitrite mixed solution pool, and an atomizing nozzle. The input end of the atomizing nozzle is connected to the nitrite mixed solution pool, and the spray end is connected to the gas pool. The atomizing nozzle is used to spray the nitrite mixed solution in the nitrite mixed solution pool into the gas pool in a mist form. The gas pool is equipped with an air inlet and an air outlet. The output end of the gas cylinder is connected to the air inlet and air outlet and then to the detection unit.

2. The gaseous nitrous acid generator according to claim 1, characterized in that: The output end of the gas cylinder is connected to the inlet, outlet and detection unit through a gas pipeline.

3. The gaseous nitrous acid generator according to claim 2, characterized in that: A first flow control valve is installed on the air inlet.

4. The gaseous nitrous acid generator according to claim 2, characterized in that: A second flow control valve is installed on the gas pipeline between the inlet and outlet.

5. The gaseous nitrous acid generator according to claim 1, characterized in that: The vent is also connected to the residual solution collection bottle.

6. The gaseous nitrous acid generator according to claim 1, characterized in that: The air inlet and air outlet are located at opposite ends of the air tank.

7. The gaseous nitrous acid generator according to claim 1, characterized in that: The solution height in the nitrite mixed solution tank should not exceed the height of the nozzle tip of the atomizing nozzle.

8. The gaseous nitrous acid generator according to claim 1, characterized in that: Optical windows are provided at both ends of the gas pool.

9. The gaseous nitrous acid generator according to claim 1, characterized in that: The temperature control unit is a constant temperature water bath.

10. A method for generating gaseous nitrous acid using any one of claims 1 to 9, characterized in that: Specifically, the steps include the following: S1: The temperature control unit is kept at the design temperature. The atomizing nozzle is turned on to spray the nitrite mixed solution in the nitrite mixed solution tank into the gas tank in a mist form. S2: Open the gas cylinder. The gas inside the cylinder is divided into two paths. One path, the carrier gas, enters the gas pool through the inlet, accelerating the diffusion of the mist-like nitrite mixed solution in the gas pool into the gas phase, promoting the evaporation and uniform dispersion of nitrite droplets. The other path, the dilution gas, directly mixes with the gaseous nitrite discharged from the outlet and enters the detection unit to obtain the required concentration of gaseous nitrite.

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