Method for producing nitrogen monoxide and nitrogen monoxide produced thereby

Abstract

The present invention provides a method for producing nitrogen monoxide and monoxide produced thereby, the method comprising the steps of: 1) removing high-boiling-point materials existing in a liquid phase by distilling a mixed gas generated in a process of producing nitric acid by reacting ammonia and oxygen in a high-boiling-point distillation column under pressure and temperature conditions in which NO2 can be vaporized; 2) removing gaseous low-boiling-point materials in a gaseous phase by distilling the mixed gas from which the high-boiling-point materials in a liquid phase are removed in a low-boiling-point material distillation column under pressure and temperature conditions in which NO2 is not vaporized; 3) obtaining NO2 in a liquid phase by supplying liquid containing NO2 to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture; 4) reacting NO2 in a liquid phase with H2O; and 5) recovering NO gas generated by the reaction.

Description

Method for producing nitrogen monoxide and nitrogen monoxide produced by the method

[0001] The present invention relates to a method for safely and efficiently producing nitrogen monoxide and high-purity nitrogen monoxide produced by the method.

[0002] High-purity nitrogen monoxide is used in a variety of applications, including semiconductor gases and medical gases. When nitrogen monoxide is used as a semiconductor gas, a purity of 99.95% or higher is required.

[0003] Nitrogen monoxide is generally produced by ammonia oxidation, the reaction of sodium nitrite with sulfuric acid, or the reaction of sodium nitrite with ferric chloride. In the ammonia oxidation method, ammonia oxidation and the chemical reactions occurring simultaneously are as follows.

[0004] NH3+ 2O2→ HNO3+ H2O (preferred overall reaction)

[0005] 4NH3+ 7O2→ 4NO2+ 6H2O (preferred reaction equation when using excess O2)

[0006] 3NO2+ 3O2→ 2HNO3+ NO (preferred reaction equation in the NO2 absorption process)

[0007] 4NH3+ 3O2→ 2N2+ 6H2O (unfavorable reaction equation)

[0008] 4NH3+ 4O2→ 2N2O + 6H2O (unfavorable reaction equation)

[0009] 2NH3+ 8NO → 5N2O + 3H2O (unfavorable reaction equation)

[0010] When producing nitrogen monoxide using the ammonia oxidation process, various reactions, such as those described above, occur, resulting in low production efficiency. Furthermore, the requirement for high-purity ammonia increases manufacturing costs. Furthermore, the use of aqueous solutions such as KMnO4 to remove unreacted ammonia leads to high wastewater treatment costs.

[0011] Meanwhile, nitrogen monoxide is a thermodynamically unstable substance that reacts as follows to form nitrogen oxides (NOx). Therefore, the purity of nitrogen monoxide is reduced, making it difficult to purify high-purity nitrogen monoxide.

[0012] 2NO + O2→ 2NO2

[0013] NO2+ NO ↔ N2O3

[0014] 2NO2↔ N2O4

[0015] Conventional technologies typically utilize ultra-low temperature cooling to remove NxOy and NOx-based substances, thereby purifying and preserving nitrogen monoxide to a high purity. This means that ultra-low temperature cooling transforms gaseous nitrogen monoxide into a solid, and substances with lower boiling points than nitrogen monoxide remain in a gaseous state. This allows for the removal of gaseous impurities, leaving nitrogen monoxide in a solid state. However, the solid nitrogen monoxide obtained through this method must undergo a phase transformation to a gaseous state before use. This process increases the risk of explosion due to rapid volume expansion, and there have been actual explosions in the United States.

[0016] In addition, conventional nitrogen monoxide manufacturing methods cannot be mass-produced due to environmental problems such as NOx gas emissions.

[0017] Therefore, improvements to these problems are required.

[0018] A prior patent related to the present invention is Republic of Korea Patent No. 10-1257794.

[0019] The present invention has been devised to solve the above problems of the prior art.

[0020] The purpose of the present invention is to provide a method for producing high-purity nitrogen monoxide with excellent safety and efficiency, which prevents the risk of explosion due to phase change of nitrogen monoxide, minimizes the generation of NOx gas, and enables recycling and use of by-products such as wastewater and waste gas, and to provide high-purity nitrogen monoxide produced by the method.

[0021] The present invention

[0022] 1) A step of removing high-boiling substances present in a liquid state by distilling the mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen in a high-boiling substance distillation tower under pressure and temperature conditions that allow NO2 to vaporize;

[0023] 2) A step of removing the gaseous low-boiling substances by distilling the mixed gas from which the liquid high-boiling substances have been removed in a low-boiling substance distillation tower under pressure and temperature conditions at which NO2 does not vaporize;

[0024] 3) A step of supplying the liquid phase containing NO2 obtained above to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture and obtain liquid NO2;

[0025] 4) A step of reacting the liquid NO2 with H2O; and

[0026] 5) A method for producing nitrogen monoxide is provided, including a step of recovering NO gas produced by the above reaction.

[0027]

[0028] *

[0029] In addition, the present invention

[0030] After step 4) of the above manufacturing method

[0031] A method for producing nitrogen monoxide is provided, which further includes a step of washing NO gas with an alkaline solution.

[0032]

[0033] In addition, the present invention

[0034] Nitrogen monoxide manufactured by the above method is provided.

[0035] According to the method for producing nitrogen monoxide of the present invention, the risk of explosion due to phase change of nitrogen monoxide is prevented, NOx gas generation is minimized, and byproducts such as wastewater and waste gas can be recycled and used, thereby significantly increasing the safety and efficiency of nitrogen monoxide production. Furthermore, high-purity nitrogen monoxide production is possible.

[0036] In addition, since the nitrogen monoxide of the present invention manufactured by the above method has a very high purity, it can be efficiently used in fields requiring high-purity nitrogen monoxide.

[0037] Figure 1 is a flow chart of the nitrogen monoxide production process of the present invention.

[0038] Figure 2 illustrates one embodiment of a plant used for producing nitrogen monoxide of the present invention.

[0039] *Explanation of major symbols in the drawing

[0040] 100: Nitric acid production reactor

[0041] 200: High-effluent distillation tower

[0042] 300: Low-carbon distillation column

[0043] 400: Adsorption tower (PSA adsorption tower)

[0044] 500: High-purity NO2 collection tank

[0045] 600: NO manufacturing reactor

[0046] 700: Alkali absorption tower

[0047] 800: Water Tower

[0048] 810: Water tower heat exchanger

[0049] 900: Compressor

[0050] 1000: Absorption tower

[0051] 1010, 1011: Cooler

[0052] 1100: Charging container

[0053] The present invention is described in detail below.

[0054] The method for producing nitrogen monoxide of the present invention is characterized by comprising the following steps.

[0055] 1) A step of removing high-boiling substances present in a liquid state by distilling the mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen in a high-boiling substance distillation tower under pressure and temperature conditions that allow NO2 to vaporize;

[0056] 2) A step of removing the gaseous low-boiling substances by distilling the mixed gas from which the liquid high-boiling substances have been removed in a low-boiling substance distillation tower under pressure and temperature conditions at which NO2 does not vaporize;

[0057] 3) A step of supplying the liquid phase containing NO2 obtained above to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture and obtain liquid NO2 (or N2O4);

[0058] 4) A step of reacting the liquid NO2 with H2O; and

[0059]

[0060] 5) A step of recovering NO gas generated by the above reaction.

[0061] Since the above NO2 also exists as N2O4, the part described as NO2 in the present invention should be understood as a concept including the existence of only NO2, the mixed form of NO2 and N2O4, and the existence of only N2O4.

[0062] The mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen in step 1) above is N 2, O 2, NO, N2O, NO 2, N2O 3, N2O 4, HNO 3, and may contain six or more of H2O, or may contain all of them.

[0063]

[0064] The method of the present invention has the characteristic of eliminating the risk of rapid pressure increase due to NO generation caused by N2O3 decomposition since the purified high-purity nitrogen dioxide does not contain N2O3. The present invention produces high-purity nitrogen monoxide by reacting the high-purity nitrogen dioxide produced as described above with water.

[0065]

[0066] In one embodiment of the present invention, the pressure and temperature conditions at which NO2 can be vaporized in step 1) may be, for example, 1 to 20 bar and 10 to 100°C, and may be 21 to 25°C, more preferably 21 to 23°C, based on a pressure of 1 bar, and the most efficient pressure and temperature at which all of NO2 can be vaporized may be preferred. Since the high-boiling water distillation column in step 1) may be a distillation column known in the art, a detailed description thereof will be omitted.

[0067] The above-mentioned solids may include nitric acid, moisture, etc.

[0068]

[0069] In one embodiment of the present invention, the pressure and temperature conditions at which NO2 is not vaporized in step 2) are 1 to 20 bar and a temperature of less than -10 to 80°C, and may be 1 to 20 bar and -10 to 10°C. In addition, the temperature may be -10°C or higher and less than 21°C based on a pressure of 1 bar. Since the distillation column in step 2) may be a low-boiling substance distillation column known in the art, a detailed description thereof will be omitted. The low-boiling substance may be N2, O2, NO, etc.

[0070]

[0071] In one embodiment of the present invention, the adsorption process in step 3) is a process of supplying a liquid phase containing NO2 to pass through an adsorbent filled in the adsorption tower, and removing impurities such as acid and moisture by adsorbing them through the adsorbent, thereby producing purified liquid NO2.

[0072] In the above step 3), the adsorbent may be a zeolite, for example, at least one selected from the group consisting of 3A, 4A, 5A, and 13X.

[0073] The operating conditions of the above adsorption tower can be set such that the temperature at the top of the adsorption tower is 25 to 60°C and the temperature at the bottom is 25 to 65°C under a pressure of 1 to 20 bar.

[0074]

[0075] In one embodiment of the present invention, the main reaction of NO2 and H2O in step 4) can be represented by the following reaction formula.

[0076] [Reaction Formula 1]

[0077] 3NO2+ H2O → 2HNO3+ NO

[0078]

[0079] The above reaction can be carried out under conditions of a pressure of 1 to 20 bar and a temperature of 10 to 150°C, preferably under conditions of a pressure of 1 to 20 bar and a temperature of 20 to 100°C, more preferably under conditions of a pressure of 5 to 20 bar and a temperature of 20 to 70°C, and even more preferably under conditions of a pressure of 5 to 15 bar and a temperature of 20 to 55°C.

[0080]

[0081] The liquid NO2 obtained in the above step 3) can be fed for the reaction in the above step 4) by heating to a temperature of 40 to 150°C, more preferably 50 to 100°C. When NO2 is fed in the above temperature range, NO can be produced with high efficiency by the above reaction formula 1 because NO2 does not exist in the N2O4 state. When NO2 exists in the N2O4 state, the reaction in the above reaction formula 1 does not occur.

[0082]

[0083] In the present invention, at least one of the high-boiling fraction containing nitric acid and moisture separated from the high-boiling fraction distillation column of step 1) and the low-boiling fraction containing N2, O2, and NO gas separated from the low-boiling fraction distillation column of step 2) can be transferred to a nitric acid production process and reused in nitric acid production.

[0084]

[0085] In addition, the method for producing nitrogen monoxide of the present invention can be performed including the following steps.

[0086] 1) A step of removing high-boiling substances present in a liquid state by distilling the mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen in a high-boiling substance distillation tower under pressure and temperature conditions that allow NO2 to vaporize;

[0087] 2) A step of removing the gaseous low-boiling substances by distilling the mixed gas from which the liquid high-boiling substances have been removed in a low-boiling substance distillation tower under pressure and temperature conditions at which NO2 does not vaporize;

[0088] 3) A step of supplying the liquid phase containing NO2 obtained above to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture and obtain liquid NO2;

[0089] 4) A step of obtaining NO gas by reacting the liquid NO2 with H2O; and

[0090] 5) Step of washing the NO gas obtained above with an alkaline solution.

[0091] Since steps 1) to 4) above can be performed in the same manner as described above, detailed descriptions are omitted.

[0092] In one embodiment of the present invention, in step 5), an alkaline solution selected from the group consisting of an aqueous NaOH solution, an aqueous KOH solution, an aqueous Ca(OH)2 solution, and an aqueous Mg(OH)2 solution may be used.

[0093] The above alkaline solution washing can be performed, for example, through an alkaline absorption tower. For example, by supplying NO gas upward from the bottom of the alkaline absorption tower, and spraying an alkaline solution in the direction of the supplied NO gas from the top of the alkaline absorption tower, impurities such as NO2 and HNO3 can be removed.

[0094] In one embodiment of the present invention, after step 5), a step of washing the obtained NO gas may be further performed.

[0095] The above washing process can be performed, for example, through a washing tower. For example, by supplying NO gas upward from the bottom of the washing tower, water (e.g., distilled water) can be sprayed from the top of the washing tower in the direction of the supplied NO gas, thereby removing alkaline components.

[0096] In one embodiment of the present invention, after the washing step, a step of drying the obtained NO gas may be further included.

[0097] The above drying step can be performed using one or more adsorbents selected from the group consisting of zeolites 3A, 4A, 5A, and 13X.

[0098] The present invention utilizes alkaline solution washing (using an alkaline absorption tower) and water washing (using a water washing tower) to remove trace amounts of CO2 and NxOy, and uses an adsorption tower (adsorbent) to remove the moisture generated during this process. High-purity nitrogen monoxide has the property of being decomposed into N2, O2, NO2, N2O, etc. by high temperatures, so the heat of adsorption generated when moisture is absorbed is controlled to 5 to 60°C to produce high-purity nitrogen monoxide.

[0099]

[0100] At least one of the high-boiler fraction containing nitric acid and water separated from the high-boiler fraction distillation tower of step 1); the low-boiler fraction containing N2, O2, and NO gases separated from the low-boiler fraction distillation tower of step 2); the wastewater discharged from the alkaline solution washing process of step 5); and the wastewater discharged from the water washing process; may be transferred to the nitric acid production process and reused in the nitric acid production process.

[0101]

[0102] The present invention also provides:

[0103] Nitrogen monoxide manufactured by the above method is provided.

[0104] The nitrogen monoxide of the present invention has the characteristic of excellent purity. That is, the nitrogen monoxide may have a purity of 99.9% or more, preferably 99.95% or more, more preferably 99.99% or more, and even more preferably 99.999% or more.

[0105]

[0106] Hereinafter, the manufacturing method of the present invention will be specifically described by way of example through the carbon monoxide manufacturing plant illustrated in FIG. 2.

[0107] Crude NO2 is supplied (10) at a pressure of 1 to 20 bar and a temperature of 20 to 500°C from a nitric acid manufacturing reactor (100) where a nitric acid manufacturing process takes place. At this time, the composition of the crude NO2 coming out at each stage of the nitric acid manufacturing process is different, and the content of NO2 included in the crude NO2 provided at this time is 1 to 99%, and the remaining components are N2, O2, N O, N2O, etc. In order to manufacture high-purity NO2, the crude NO2 supplied in this way removes nitric acid, moisture, etc., which are higher in boiling point than NO2, in a high-boiling point distillation tower (200) at a pressure of 1 to 20 bar and a temperature of 21 to 100°C. The crude NO2 gas, from which high-boiling points such as nitric acid and moisture have been almost completely removed, is supplied (20) to a low-boiling point distillation tower (300). In addition, high-boiling points such as moisture and nitric acid coming out of the high-boiling point distillation tower (200) are recycled (21) to a nitric acid production reactor (100) to manufacture nitric acid. The low-boiling point distillation tower (300) is operated at a pressure of 1 to 20 bar and a temperature of -10 to 80°C, preferably -10 to 40°C, and must be operated so that supercooling does not occur and N2O3 is not generated. N2, O2, NO, etc., which are lower in boiling point than NO2 separated from the low boiling point distillation tower, are recycled (31) to the nitric acid production reactor (100). In addition, the high-purity NO2 containing a small amount of moisture and nitric acid separated from the low boiling point distillation tower is supplied (30) to the adsorption tower (400), where the small amount of moisture and nitric acid are removed by the adsorbent. Some of the high-purity NO2 produced in this way is supplied (41) to the high-purity NO2 collection tank (500), and some is supplied (42) to the high-purity NO production reactor (600). The NO2 supplied (42) to the high-purity NO production reactor (600) reacts with distilled water (62) to produce high-purity NO (60). At this time, the pressure of the reactor is maintained at 1 to 20 bar, and the temperature is maintained at 10 to 150°C to perform the reaction. At this time, if the temperature and pressure are high, impurities such as N2, O2, and N2O are formed, and if the temperature and pressure are low, high-purity NO can be obtained, but the production yield is low. The high-purity NO manufactured in this way is supplied (60) to an alkaline absorption tower (700), where the NO gas comes into contact with an alkaline solution, thereby removing impurities such as N2O and nitric acid. The high-purity NO obtained in the above step is supplied (70) to a washing tower (800) and a washing process is performed.Since the high-purity NO after washing contains a large amount of moisture, the moisture is removed through a washing tower heat exchanger (810). Thereafter, the high-purity NO gas is supplied to a compressor (900). The wastewater (71, 81) from the alkali absorption tower (700) and washing tower (800) is recycled to the nitric acid process and reused in the neutralization treatment or nitric acid manufacturing process. The high-purity NO gas is compressed to 1 to 100 bar in the compressor (900). Thereafter, the compressed high-purity NO gas is supplied to the absorption tower (1000), where trace amounts of moisture and impurities are removed. The high-purity NO gas (111) thus manufactured is charged into a charging tank (1100) at 20 to 100 bar.

[0108]

[0109] The above process can be performed under the following conditions.

[0110] Press.Temp. (℃)Upper and lower partsHigh-boiling water distillation tower (200)107390Low-boiling water distillation tower (300)93572Adsorption tower (400)85051NO production reactor (600)54651Alkali absorption tower (700)4.53235Water washing tower (800)4530Adsorption tower (1000)303210

[0111] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by these examples. Those skilled in the art may appropriately modify or alter the following examples within the scope of the present invention.

[0112] Comparative Example 1: NO2 production through gas-liquid separation

[0113] In the nitric acid manufacturing process, a mixed gas was supplied, moisture was removed, and NO2 gas-liquid separation was performed. The components were analyzed by GC, FT-IR, and wet analysis, and the analysis results are shown in Table 2.

[0114] Press. (Bar)Temp. (℃)Components (%)O2N2H2ONONO2 / N2O3N2OHNO3550Feed (Gas)0.56390.790.9142.1535.3660.1870.02755Gas-Liquid SeparationGas0.6591.790.0152.3294.9170.2950.002Liq.-0.01212.480.05286.120.0431.29850Gas-Liquid SeparationGas0.65292.090.0042.3364.6260.2960.001Liq.-0.0123.680.0695.870.0690.312

[0115] Comparative Example 2: Manufacturing of NO using NO2 (including N2O3)

[0116] The liquid NO2 / N2O3 obtained in Comparative Example 1 was reacted with distilled water to produce NO. The reaction pressure was maintained at 5 bar and the reaction temperature was 50°C. At this time, the selectivity was 98.71% and the yield was 43.51%. The product was analyzed by GC, FT-IR, and wet analysis, and the results are shown in Table 3.

[0117] Components(%)O2-N20.012CO0.0001CO20.0002H2O0.52NO43.51NO255.92N2O0.0002HNO30.035Etc0.0011

[0118]

[0119] Example 1: Production of high-purity NO

[0120] In the nitric acid manufacturing process, a mixed gas containing NO2 and NO was supplied, high-boiling substances were removed, low-boiling substances were removed, and the mixed gas was supplied to an adsorption tower filled with MS-5A adsorbent to perform purification.

[0121] <Gobisulmul Removal Process>

[0122] The above mixed gas was distilled at 10 bar and 70 to 90°C in a high-boiler distillation tower to remove high-boiler materials existing in liquid form.

[0123] <Low-cost removal process>

[0124] The mixed gas from which the liquid high-boiling substances were removed was distilled at 9 bar and 35 to 72°C in a low-boiling substance distillation tower to remove the gaseous low-boiling substances.

[0125] <Adsorption process>

[0126] The liquid phase containing the NO2 obtained above was supplied to an adsorption tower filled with MS-5A adsorbent, and impurities such as acid and moisture were adsorbed by the adsorbent to obtain high-purity liquid NO2.

[0127] The above purification results were as shown in Table 4 below.

[0128] Componets(%)FeedHigh-boiling water distillation column (high-boiling water removal)Low-boiling water distillation column (low-boiling water removal)DryerGasLiq.GasLiq.MS-5AN292.096.1072.11919498.48--O20.5820.5960.0160.61--NO2.134-0.0000770.310.0010.0008N2O0.1900.1980.0060.202--N O22.7940.7527.8290.3959.84799.999N2O30.0962.28012.994---N2O41.202-2 5.398-39.536-HNO30.1230.03425.692-0.308-WATER0.8790.03425.945-0.308-

[0129] Example 2: NO Production by Reaction of High-Purity NO2 and WaterThe high-purity NO2 produced in Example 1 was reacted with water to produce NO. The pressure was maintained at 1 to 20 barg and the temperature at 20 to 100°C. FT-IR and wet analysis were performed, and the results are shown in Table 5 below.

[0130] Press(bar)202020101010555111Temp.(℃)2050100205010020501002050100Sele.(%)98.7399.0181.5298. 1599.6587.0599.6299.7893.5899.6999.5297.43Yield(%)33.2670.4865.7129.2654.0553.2218.0542.88 45.2912.6216.7318.94GasComponents(%)O2-0.021.51--1.03--0.87--0.01N20.050.073.350.010.0012. 74--1.25--0.02CO0.020.020.0180.0150.00010.0001------CO20.040.0360.0370.020.00010.0001------ H2O0.30.453.410.420.151.870.050.0670.880.030.0570.35NO99.4699.2084.8799.4299.6491.5699.919 9.3396.1399.7396.1490.96NO20.0110.0980.2300.0250.1700.5200.0230.5730.7600.2353.7838.537N2O0 .0030.0075.340.0050.000020.19-0.0050.052--0.002HNO30.010.11.230.050.030.970.0120.02150.049 80.0090.0220.106Etc0.10600.00170.00100.03150.00860.11710.00690.00100.00530.00020.00170.0116

[0131]

[0132] Example 3: Removal of impurities and moisture for producing high-purity NO

[0133] In order to manufacture high-purity NO from the NO gas obtained in Example 2, impurities were removed in an alkaline absorption tower, and then the alkaline components were removed by washing with water. In order to secure high-purity NO, moisture was removed through an adsorption tower. At this time, MS-3A, MS-4A, MS-5A, and 13X were used as adsorbents, and tests were conducted by changing the temperature and pressure.

[0134] Specifically, while supplying NO gas upward from the bottom of an alkaline absorption tower, an alkaline solution (e.g., NaOH aqueous solution or KOH aqueous solution) is sprayed in the direction of the supplied NO gas from the top of the alkaline absorption tower to remove impurities such as acids, and then the NO gas from which the impurities have been removed is supplied upward from the bottom to a washing tower, and water (or pure water) is sprayed in the direction of the supplied NO gas from the top of the washing tower to wash the NO gas, thereby removing the alkaline components.

[0135] Thereafter, the purified NO gas was dried by passing it through an adsorption tower equipped with an adsorbent such as MS-3A, MS-4A, MS-5A, or 13X at varying temperatures and pressures.

[0136]

[0137] The above results were analyzed using GC and FT-IR, and the results were as shown in Tables 6 and 7 below.

[0138]

[0139] Feed알칼리흡수탑수세탑MS-3AMS-4AMS-5AMS-13XPress.(bar)54.5430303030Temp.(℃)50252527627368Components(%)O2----0.00010.0010.001N2----0.00030.0020.0015H2O0.0670.120.080.00020.00010.000070.00005NO99.33299.87499.91699.99699.99699.99499.994NO20.57------N2O0.0050.0040.0040.0040.00380.00340.0037HNO30.02150.002-----Etc0.0010------

[0140]

[0141] FeedMS-4AMS-5APress.(bar)-203050203050203050Temp.(℃)-303030303030505050Components(%)O2----------N2----------H2O0.080.00010.000080.000030.000090.000060.000030.000110.00010.0001NO99.91699.99799.99899.99899.99899.99999.99999.99899.99999.999NO2----------N2O0.0040.00320.00210.0020.00150.00080.00050.00190.00120.0008HNO3----------Etc----------

Claims

1. 1) The mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen is distilled from a high-volume distillation tower to NO 2 A step of removing solid matter existing in a liquid phase by distillation under conditions of vaporizable pressure and temperature; 2) The mixed gas from which the above liquid high-temperature substances have been removed is distilled in a low-temperature distillation tower to remove NO. 2 A step of removing low-boiling gaseous substances by distillation under non-vaporizing pressure and temperature conditions; 3) NO obtained from the above 2 The liquid containing NO is supplied to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture, thereby removing the NO in the liquid. 2 Steps to obtain ; 4) The above liquid NO 2 To H 2 Step of reacting with O; and 5) A method for producing nitrogen monoxide, comprising: a step of recovering NO gas produced by the above reaction.

2. In paragraph 1, NO in step 1) above 2 A method for producing nitrogen monoxide, characterized in that the vaporizable pressure and temperature conditions are 1 to 20 bar and 10 to 100°C.

3. In paragraph 2, NO in step 1) above 2 A method for producing nitrogen monoxide, characterized in that the pressure and temperature conditions at which vaporization is possible are 21 to 25°C based on 1 bar.

4. In paragraph 1, NO in step 2) above 2 A method for producing nitrogen monoxide, characterized in that the pressure and temperature conditions at which nitrogen monoxide is not vaporized are 1 to 20 bar and -10 to less than 80°C.

5. In paragraph 1, NO in step 2) above 2 A method for producing nitrogen monoxide, characterized in that the pressure and temperature conditions at which nitrogen monoxide is not vaporized are 1 to 20 bar and the temperature is -10 to 10℃.

6. In paragraph 1, A method for producing nitrogen monoxide, characterized in that in step 3), the adsorbent is at least one selected from the group consisting of zeolites 3A, 4A, 5A, and 13X.

7. In paragraph 1, NO in step 4) above 2 Wow H 2 A method for producing nitrogen monoxide, characterized in that the reaction of O is performed under conditions of a pressure of 1 to 20 bar and a temperature of 10 to 150°C.

8. In paragraph 7, NO in step 4) above 2 Wow H 2 A method for producing nitrogen monoxide, characterized in that the reaction of O is performed under conditions of a pressure of 5 to 20 bar and a temperature of 20 to 70°C.

9. In paragraph 8, NO in step 4) above 2 Wow H 2 A method for producing nitrogen monoxide, characterized in that the reaction of O is performed under conditions of a pressure of 5 to 15 bar and a temperature of 20 to 55°C.

10. In paragraph 1, 1) High-boiler water containing nitric acid and water separated from the high-boiler distillation tower of the stage; and 2) N separated from the low-carbon distillation column in the step 2 , O 2 , and low-carbon substances including NO gas; A method for producing nitrogen monoxide, characterized in that at least one of the low-carbon substances is transported to a nitric acid production process and reused in the nitric acid production process. 11.1) The mixed gas generated in the process of producing nitric acid by reacting ammonia and oxygen is distilled from a high-volume distillation tower to NO 2 A step of removing solid matter existing in a liquid phase by distillation under conditions of vaporizable pressure and temperature; 2) The mixed gas from which the above liquid high-temperature substances have been removed is distilled in a low-temperature distillation tower to remove NO. 2 A step of removing low-boiling gaseous substances by distillation under non-vaporizing pressure and temperature conditions; 3) NO obtained from the above 2 The liquid containing NO is supplied to an adsorption tower filled with an adsorbent to separate impurities including acid and moisture, thereby removing the NO in the liquid. 2 Steps to obtain ; 4) The above liquid NO 2 To H 2 A step of obtaining NO gas by reacting with O; and 5) A method for producing nitrogen monoxide, comprising a step of washing the NO gas obtained above with an alkaline solution.

12. In paragraph 11, In the above step 5), the alkaline solution is KOH aqueous solution, NaOH aqueous solution, Ca(OH 2 ) aqueous solution, and Mg(OH) 2 A method for producing nitrogen monoxide, characterized in that the nitrogen monoxide is selected from the group consisting of aqueous solutions.

13. In paragraph 11, A method for producing nitrogen monoxide, characterized in that it further comprises a step of washing the obtained NO gas after the above step 5).

14. In paragraph 13, A method for producing nitrogen monoxide, characterized in that it further comprises a step of drying the obtained NO gas after the above washing step.

15. In paragraph 14, A method for producing nitrogen monoxide, characterized in that the drying step is performed using at least one adsorbent selected from the group consisting of zeolites 3A, 4A, 5A, and 13X.

16. In paragraph 11, 1) High-boiler water containing nitric acid and water separated from the high-boiler water distillation tower of the stage; 2) N separated from the low-carbon distillation column in the step 2 , O 2 , and low-carbon water containing NO gas; and 5) A method for producing nitrogen monoxide, characterized in that at least one of the wastewater discharged from the alkaline solution washing process of step 5) is transported to the nitric acid production process and reused in the nitric acid production process.

17. Nitrogen monoxide manufactured by the method of paragraph 1 or paragraph 11.

18. In paragraph 17, The above nitrogen monoxide is characterized by having a purity of 99.9% or higher.

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