WO2018225979A1 - High-frequency induction heating pyrolysis process for nitrous oxide-containing gaseous compound - Google Patents

Abstract

The present invention relates to a high-frequency induction heating pyrolysis process enabling the treatment of nitrous oxide-containing gas mixture exhaust gas discharged in an adipic acid production process, a nitric acid production process, a caprolactam production process and a nitrous oxide production process. The high-frequency induction heating pyrolysis process, according to the present invention, comprises: a high-frequency induction heating pyrolysis reactor for decomposing a nitrous oxide-containing gas mixture into nitrogen and oxygen; a high-frequency induction heating system; and a heat exchanger for recovering energy from a high-temperature pyrolyzed gas mixture. The nitrous oxide-containing gas mixture is supplied to the heat exchanger, is preheated by means of the high-temperature decomposed gas mixture discharged from the high-frequency induction heating pyrolysis reactor, and is supplied to the high-frequency induction heating pyrolysis reactor. The internal temperature of the high-frequency induction heating pyrolysis reactor is controlled by the high-frequency induction heating system so as to preferably be within a range of 800 to 1,200. The retention time of the nitrous oxide-containing gas mixture in the high-frequency induction heating pyrolysis reactor is preferably 0.5 to 5 seconds.

Description

High Frequency Induction Heating Pyrolysis Process of Nitrous Oxide-containing Gas Compounds

The present invention relates to a pyrolysis process for treating nitrous oxide (N ₂ O) -containing gas mixture discharged from chemical processes such as adipic acid production process, nitric acid production process, caprolactam production process and nitrous oxide production process. Specifically, the present invention relates to a high frequency induction heating pyrolysis process for decomposing nitrous oxide causing global warming into nitrogen and oxygen.

In chemical processes such as adipic acid, nitric acid, and caprolactam production processes, gaseous mixtures containing nitrous oxide are emitted as exhaust gases. Nitrous oxide is a greenhouse gas with a global warming index of more than 300 times that of nitrous oxide. To protect the global environment, nitrous oxide emitted from chemical processes should be decomposed and treated. Nitrous oxide-containing gas mixtures from industry should be reduced as much as possible.

In the absence of a catalyst, nitrous oxide begins to decompose above about 800 ° C. As the temperature increases, the rate of decomposition of nitrous oxide into nitrogen and oxygen increases, but the production of nitrogen monoxide (NO) increases above 1,000 ° C. Nitrogen monoxide decomposes into nitrogen and oxygen above about 1,500 ° C. This requires precise temperature control after the reaction has started. In particular, when the concentration of nitrous oxide is high, temperature control is more important because of the large amount of heat generated. Special care is needed to regulate the production of environmentally tightly regulated NO _x during the pyrolysis of nitrous oxide.

Various methods have been proposed as a method of reducing nitrous oxide generated in the chemical process. Most proposed methods relate to the decomposition of nitrous oxide into nitrogen and oxygen. These methods can be divided into two types, pyrolysis method (DE 4,116,950) which decomposes by heat without using a catalyst, and catalytic decomposition method (US 6,723,295) using a catalyst. The pyrolysis method of the present pyrolysis method and catalytic decomposition method is described below.

1 shows an overview of a pyrolysis apparatus currently used to treat high concentrations of nitrous oxide containing 30 to 50% of the adipic acid production process. The pyrolysis apparatus of nitrous oxide is composed of two stage combustion furnaces of the first pyrolysis furnace 101 and the second pyrolysis furnace 102 of FIG. 1. A nitrous oxide-containing gas mixture, a natural gas fuel, and air are supplied to the first pyrolysis furnace 101 of FIG. 1 to decompose nitrous oxide at a high temperature obtained by combustion heat generated while burning natural gas. The reaction equation of the pyrolysis is as follows. Nitrous oxide is combusted to produce carbon dioxide (CO ₂ ) and water (H ₂ O).

CH ₄ + 4N ₂ O → CO ₂ + 2H ₂ O + 4N ₂

The temperature of the first pyrolysis furnace 101 of FIG. 1 is about 1,300 ° C. and natural gas in order to minimize the generation of unwanted by-product gases such as nitrogen monoxide (NO) and nitrogen dioxide (NO ₂ ) while promoting complete decomposition of nitrous oxide. Is supplied in excess. Incomplete oxidation of natural gas results in byproducts of carbon monoxide (CO) and hydrogen (H ₂ ). The gas discharged from the first pyrolysis furnace 101 of FIG. 1 is cooled in the heat exchanger 102 of FIG. 1 cooled by air and supplied to the second pyrolysis furnace 103 of FIG. 1. The air heated in the heat exchanger 102 of FIG. 1 is supplied to the second pyrolysis furnace 103 of FIG. 1 and used as combustion air. Carbon monoxide and hydrogen by-produced in the first pyrolysis furnace 101 of FIG. 1 are completely burned at a temperature of about 950 ° C. in the second pyrolysis furnace 103 of FIG. 1. In order to remove NO _x generated in this process, ammonia is supplied to the rear of the second pyrolysis furnace 103 of FIG. 1. The steam is produced in the steam generator 104 of FIG. 1 using the high temperature decomposition gas mixture discharged from the second pyrolysis furnace 103 of FIG. 1 to recover energy. As such, the pyrolysis process currently used in the adipic acid production process is a two-stage pyrolysis process and is a complex process such as additional supply of natural gas fuel and ammonia. In addition, it is an energy consumption process using natural gas fuel, and there is a disadvantage in that carbon dioxide, which is a greenhouse gas, is additionally generated during the pyrolysis process.

In the catalytic decomposition process of the nitrous oxide-containing gas mixture which is currently used for the exhaust gas treatment of nitric acid production process and caprolactam production process, a tube-type reactor filled with a catalyst is used. In the catalytic cracking process, unlike pyrolysis, an electric heater is mounted in the cracking reactor and heated to the cracking temperature. Catalytic processes are mainly used for the decomposition of low concentration gaseous mixtures with nitrous oxide concentrations of about 1%. In the nitric acid and caprolactam production process, a low concentration gas mixture with a nitrous oxide concentration of about 1% is generated, and a catalytic cracking process is used for the treatment thereof. Catalytic decomposition has a decomposition temperature of 400 to 600 ° C., which is lower than pyrolysis without a catalyst. However, catalytic decomposition has a disadvantage in that activity is inferior due to poisoning of the catalyst even when impurities are present in the concentration of ppm unit in the gas to be treated. Therefore, in catalytic cracking, the impurity composition of the nitrous oxide-containing gas mixture supplied must be maintained to meet certain standards. In addition, since the decomposition of nitrous oxide is a strong exothermic reaction, the severe change in the concentration of nitrous oxide in the gas mixture supplied to the catalytic cracking device leads to the occurrence of severe hot spots inside the catalytic cracking reactor, resulting in partial damage of the catalyst. Brings about. Due to the exothermic reaction, the temperature inside the reactor is greatly increased, which increases the catalyst and the catalyst support, thereby degrading the catalyst activity and the lifetime. In addition, catalytic decomposition has the disadvantage of promoting the decomposition of nitrous oxide to nitride oxide (NO _x ) to increase the production of nitride oxide. In general, the catalytic cracking process is less stable with time, so the pyrolysis process without a catalyst for nitrous oxide decomposition is more preferred.

As described above, the conventional pyrolysis method and the catalytic decomposition method each have disadvantages. Therefore, there is a need for a new pyrolysis method that can improve this.

<Preceding technical literature>

<Patent Documents>

(Patent Document 1) DE 4,116,950

(Patent Document 2) US 6,723,295

As described above, the pyrolysis process currently used in the adipic acid production process includes a first pyrolysis furnace operated at 1,300 ° C. and a second pyrolysis furnace operated at 950 ° C., and additional natural gas fuel and ammonia should be supplied. Etc. is a complicated process. In addition, it is an energy consumption process using natural gas fuel, and there is a disadvantage in that carbon dioxide, which is a greenhouse gas, is additionally generated during the pyrolysis process. The present invention can improve the complexity and energy consumption of the process, which is a disadvantage of the existing pyrolysis process, and to improve the instability of the catalyst and the process, which is a disadvantage of the catalytic decomposition process.

 The present inventors have led to the present invention by devising a new pyrolysis process that can be carried out in-depth study to improve the disadvantages of existing pyrolysis and catalytic decomposition process. The present invention provides a novel pyrolysis process using a high frequency induction heating pyrolysis reactor to treat nitrous oxide containing gaseous compounds. The pyrolysis process of nitrous oxide-containing gas mixtures using a high frequency induction heating pyrolysis reactor is a new process that is completely different from the pyrolysis process and the catalytic process currently used commercially.

In the high frequency induction heating pyrolysis process according to the embodiment of the present invention, in the high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture, the high frequency induction heating pyrolysis reactor for decomposing the nitrous oxide containing gas mixture and the nitrous oxide in the high frequency induction heating pyrolysis reactor Decomposing the nitrous oxide containing gas mixture using a high frequency induction heating system for heating the containing gas mixture (step 1); And recovering energy from the high temperature pyrolysis gas mixture passed through step 1 using a heat exchanger (step 2).

In addition, the high frequency induction heating pyrolysis reactor has a high frequency induction coil disposed outside, and the high frequency induction coil is a copper tube, and cooling water is supplied inside the tube to cool the high frequency induction heating pyrolysis reactor to the tube wall. High frequency can be supplied.

In addition, the high frequency induction heating pyrolysis reactor may be manufactured using a metal material that can be used at a temperature of 1,000 ° C or more.

In addition, the pyrolysis reactor may be manufactured using an Inconel material.

In addition, the filling material is filled in the high frequency induction heating pyrolysis reactor, the filling material is made of at least one of metal, ceramic and aluminum nitride, the diameter of the filling material is 3 to 30mm, the filling material is a metal The metal used, if made, may include Inconel.

In addition, the diameter (D) of the high frequency induction heating pyrolysis reactor may be 0.5 to 20cm, the length (L) may satisfy that the L / D value is 5 to 100.

In addition, the high frequency induction heating system includes a high frequency generator for generating a high frequency, a cooling system for cooling the high frequency generator and the high frequency induction coating, and a temperature control system for controlling the temperature of the high frequency induction heating pyrolysis reactor, The high frequency generated by the high frequency generator may be 3 ~ 30MHz.

In addition, the nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor for pyrolysis includes at least one impurity of oxygen, nitrogen, nitride oxides, sulfides and other pollutants, and the pyrolysis efficiency is influenced by the concentration of the impurity. May not receive.

In addition, the internal temperature of the high frequency induction heating pyrolysis reactor can be maintained at 800 to 1,200 ℃.

In addition, the pressure of the high frequency induction heating pyrolysis reactor may be 1 to 10bar.

In addition, the residence time of the nitrous oxide-containing gas mixture in the high frequency induction heating pyrolysis reactor may vary depending on the temperature and pressure in the high frequency induction heating pyrolysis reactor, which may be 0.5 to 5 seconds based on the conditions of 1 atmosphere and 25 ° C.

The heat exchanger may recover energy from the high temperature pyrolysis gas mixture passed through step 1 by preheating the nitrous oxide containing gas mixture supplied to the high frequency induction heating pyrolysis reactor using the high temperature pyrolysis gas mixture passed through step 1. Can be.

The high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture of the present invention is a new process that can improve the disadvantages of the pyrolysis process and the catalytic decomposition process currently used commercially. The high frequency induction heating pyrolysis process of the nitrous oxide-containing gas mixture of the present invention does not use a catalyst, and is a one-stage pyrolysis process that can shorten the process compared to the conventional two-stage pyrolysis process.

High-frequency induction heating of the invention the thermal decomposition process can be minimized (NO _x, such as _{NO, NO 2, N 2 O} 4) generating nitrous oxide-containing gas mixture is completely while decomposing to nitrogen and oxygen nitride oxide by-product was treated in . In addition, since it does not use the natural gas fuel used in the conventional pyrolysis process, it is an environmentally friendly process that does not generate additional greenhouse gas carbon dioxide. The high frequency induction heating pyrolysis process of the present invention does not use a catalyst and is a simple process compared to the conventional pyrolysis process, has a low decomposition temperature and does not use fuel, thereby reducing energy consumption.

The high frequency induction heating system used in the high frequency induction heating pyrolysis process of the present invention heats the pyrolysis reactor directly, so that the thermal efficiency is very good compared to other heating devices. Moreover, no preheating or cooling is required, and the heating time is short, reducing heat consumption. Although the thermal efficiency of a general electric heater is about 45%, the high frequency induction heating apparatus of the high frequency induction heating pyrolysis process of the present invention has a thermal efficiency of 90% or more, thereby greatly saving energy.

1 shows a pyrolysis process of a conventional nitrous oxide-containing gas mixture.

Figure 2 shows a high frequency induction heating pyrolysis process of the nitrous oxide containing gas compound according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail through examples. The examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited by these examples in accordance with the gist of the present invention. The analytical method used for the pyrolysis experiment and the pyrolysis rate of the nitrous oxide-containing gas mixture and the residence time calculation method in the pyrolysis reactor are summarized below.

In the high frequency induction heating pyrolysis process according to the embodiment of the present invention, in the high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture, the high frequency induction heating pyrolysis reactor for decomposing the nitrous oxide containing gas mixture and the nitrous oxide in the high frequency induction heating pyrolysis reactor Decomposing the nitrous oxide containing gas mixture using a high frequency induction heating system for heating the containing gas mixture (step 1); And recovering energy from the high temperature pyrolysis gas mixture passed through step 1 using a heat exchanger (step 2).

A schematic diagram of the high frequency induction heating pyrolysis process of the present invention is shown in FIG. 2.

The nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor of FIG. 2 is preheated by the high temperature exhaust gas discharged from the high frequency induction heating pyrolysis reactor 202 of FIG. 2 in the heat exchanger 201 of FIG. The nitrous oxide-containing gas mixture to be treated is supplied to the heat exchanger 201 of FIG. 2 and preheated to a high temperature decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor 202 and heated up to a temperature of 400 to 600 ° C. The preheated nitrous oxide containing gas mixture is fed to the high frequency induction heating pyrolysis reactor 202 of FIG. 2 to decompose into nitrogen and oxygen. The high frequency induction heating pyrolysis reactor 202 of FIG. 2 is heated by the high frequency induction heating system 203 of FIG.

The internal temperature of the high frequency induction heating pyrolysis reactor 202 of FIG. 2 is controlled in the range of 800-1,200 by the high frequency induction heating system 203 of FIG. The inlet and outlet temperatures of the high frequency induction heating pyrolysis reactor 202 of FIG. 2 are measured by the temperature indicator 204 and the temperature indicator 206 of FIG. 2. The temperature control system 205 installed in the middle of the high frequency induction heating pyrolysis reactor 202 of FIG. 2 and the high frequency induction heating system 203 of FIG. 2 control the temperature of the pyrolysis reactor. The decomposed gas mixture discharged from the high frequency induction heating pyrolysis reactor 202 of FIG. 2 is supplied to the heat exchanger 201 of FIG. 2 while preheating the nitrous oxide containing gas mixture supplied to the high frequency induction heating pyrolysis reactor 202. Is recovered, cooled and discharged to the atmosphere.

 The main features of the high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture of the present invention include the following.

 The nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis process of the present invention may contain impurities such as nitride oxides, sulfides and other pollutants as well as oxygen and nitrogen. The pyrolysis efficiency of the high frequency induction heating pyrolysis process of the present invention is not affected by the concentration of impurities such as oxides, sulfides and other pollutants as well as oxygen and nitrogen.

The internal temperature of the high frequency induction heating pyrolysis reactor can be maintained at 800 to 1,200 ℃.

The internal temperature of the high frequency induction heating pyrolysis reactor used in the high frequency induction heating pyrolysis step of the present invention is preferably maintained in the range of 800 to 1,200 ° C. More preferable temperature is 900-1,100 degreeC. At this temperature, nitrous oxide is completely decomposed into nitrogen and oxygen, thereby minimizing the production of nitrous oxides such as by-products nitrogen monoxide, nitrogen dioxide, and dinitrogen tetraoxide (N ₂ O ₄ ).

The pressure of the high frequency induction heating pyrolysis reactor may be 1 to 10 bar.

The pressure of the high frequency induction heating pyrolysis reactor can vary widely depending on the external boundary conditions (the pressure of the process) and is not limited to a specific pressure. In our experience, the most economically favorable pressure range is 1 to 10 bar.

The residence time of the nitrous oxide-containing gas mixture in the high frequency induction pyrolysis reactor varies depending on the temperature and the pressure in the high frequency induction pyrolysis reactor, which may be 0.5 to 5 seconds based on the conditions of 1 atmosphere and 25 atmospheres.

The residence time of the nitrous oxide containing gas mixture in the high frequency induction heating pyrolysis reactor used in the high frequency induction heating pyrolysis reactor of the present invention varies depending on the temperature and the pressure in the high frequency induction heating pyrolysis reactor, based on the conditions of 1 atm and 25 ° C. To 5 seconds is preferred. More preferable residence time is 1-3 seconds. The residence time has to be adjusted according to the decomposition temperature, and it must be possible to minimize the formation of nitrous oxide (NO _x ) as nitrous oxide is completely decomposed.

The heat exchanger may recover the energy of the high temperature pyrolysis gas mixture passed through step 1 by preheating the nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor using the high temperature pyrolysis gas mixture passed through step 1. .

 In the high frequency induction heating pyrolysis process of the present invention, the nitrous oxide-containing gas mixture supplied to the high frequency induction pyrolysis reactor is recovered by recovering energy from the high temperature (800-1,200 ° C.) decomposition gas mixture discharged from the high frequency induction pyrolysis reactor using a heat exchanger. Preheat.

The high frequency induction heating pyrolysis reactor used in the high frequency induction heating pyrolysis process of the present invention has the following characteristics.

The high frequency induction coil mounted on the high frequency induction heating reaction system may be a copper tube, in which a coolant is supplied and cooled, and a high frequency is supplied to the tube wall.

 The high frequency induction coil is mounted outside the pyrolysis half of the high frequency induction heating apparatus of the present invention. The high frequency induction coil is a copper tube, and cooling water is supplied inside the tube to cool the high frequency.

The high frequency induction heating system of the high frequency induction heating apparatus of the present invention comprises a high frequency generator, a high frequency generator and a cooling system for cooling the high frequency induction coating, and a temperature control system for controlling the temperature of the reactor. The range of 3-30 MHz is preferred.

The pyrolysis reactor may include a metal material that can be used at a high temperature of 1,000 ° C. or higher.

The high frequency induction heating pyrolysis reactor of the high frequency induction heating apparatus of the present invention is made of a metal material having excellent durability at a high temperature of 1,000 ° C. or higher. In particular, it is preferable to use Inconel, which is an alloy containing 15% of chromium, 6-7% of iron, 2.5% of titanium, 1% of aluminum, manganese, and silicon mainly based on nickel.

Filling material is filled in the high frequency induction heating pyrolysis reactor, the filling material may be made of at least one of metal, ceramic and aluminum nitride.

The filling material is filled in the high frequency induction heating pyrolysis reactor of the high frequency induction heating apparatus of the present invention. The filling material is to increase the contact area and the heat transfer area of the nitrous oxide gas for efficient pyrolysis. The filling material is preferably made of a material such as metal, ceramic or aluminum nitride.

The diameter of the filler material may be 3 to 30mm.

The size of the filling material increases depending on the diameter of the reactor, preferably 3 to 30 mm in diameter. In the case of using the metal as a filling material, it is preferable to use a metal having excellent durability at a high temperature of 1,000 ° C. or higher, and particularly, an Inconel metal material.

The diameter (D) of the high frequency induction heating pyrolysis reactor of the high frequency induction heating apparatus of the present invention is preferably 0.5 to 20 cm. Especially 1-10 cm is the most preferable. Since the decomposition reaction of nitrous oxide is an exothermic reaction, the larger the diameter of the pyrolysis reactor, the more difficult it is to maintain a uniform temperature inside the pyrolysis reactor. The length (L) of the high frequency induction heating pyrolysis reactor is preferably 5 to 100 based on L / D. Especially 10-50 (L / D) is the most preferable.

<Method for analyzing nitrous oxide concentration>

The gas chromatography (GC) method was used to measure the concentration before and after pyrolysis of the nitrous oxide-containing gas mixture. PDD (Pulsed Discharge Detector) was used as a detector of GC, and Carboxene 1010 PLOT was used as an analytical column. In addition, the analysis of high concentration nitrous oxide was used TCD (Thermal Conductivity Detector).

GC analysis conditions are summarized in Table 1.

Analyzer	YL Instrument 6500 GC system
Detector	PDD, TCD
Conveying gas	He (10.0 mL / min)
column	Carboxen-1010 PLOT, 30 m x 0.53 mm I.D.
Inlet temperature	200 ℃
Detector temperature	200 ℃
Column temperature	150 ℃
Sample volume	50 μL

<Method for analyzing concentration of nitrogen monoxide, nitrogen dioxide and nitride oxide> Nitrous oxide is mainly decomposed into nitrogen and oxygen by pyrolysis, but can also be decomposed into nitrogen monoxide and oxygen. In order to confirm the decomposition of nitrous oxide into nitrogen monoxide and oxygen, the gas mixture after pyrolysis of the nitrous oxide-containing gas mixture was analyzed by a NO _x analyzer (Model T2000) using chemiluminescence.

The main specifications of the used NO _x analyzers are summarized in Table 2 below.

Analysis method	Chemiluminescence
Analytical Concentration Range	0-20 ppm
Measured concentration	0.4 ppb
Temperature range	5 ~ 40 ℃
flux	0.5 liter / min

Calculation of Nitrous Oxide Decomposition Ratio Nitrous oxide concentrations before and after pyrolysis of the nitrous oxide-containing gas mixture were analyzed to calculate the nitrous oxide decomposition rate (%) by dividing the concentration after pyrolysis by the concentration before pyrolysis.

<Residence Time in High Frequency Induction Heating Pyrolysis Reactor of Nitrous Oxide-containing Gas Mixture>

The volume of the reactor is calculated from the diameter and length of the high frequency induction heating pyrolysis reactor. In this case, it is assumed that the inside of the high frequency induction heating pyrolysis reactor is not filled with a filling. The residence time is calculated by dividing the volume of the calculated high frequency induction heating pyrolysis reactor by the supply flow rate of nitrous oxide containing gas mixture (based on 1 atmosphere and 25 ° C).

<Example 1>

Experiments were carried out with a high frequency induction heating pyrolysis process as shown in FIG. 2. The high frequency induction heating pyrolysis reactor (202 in FIG. 2) was 1 inch (2.54 cm) in diameter and 40 cm long. The inside of the high frequency induction heating pyrolysis reactor was filled with a 1/4 inch diameter (0.635 cm) and 0.5 cm long filler. The high frequency induction heating pyrolysis reactor and the filler were each made of Inconel metal. Around the high frequency induction heating pyrolysis reactor, a copper high frequency induction coil tube was mounted, and the temperature inside the high frequency induction heating pyrolysis reactor was controlled by a high frequency induction heating system ((203) of FIG. 2). The wavelength of the high frequency generated in the high frequency induction heating system was 25 kHz, and the maximum electrical energy that could be generated in the installed high frequency heating coil was 10 kw. The temperature inside the high frequency induction pyrolysis reactor was measured at three points: the reactor inlet, the middle of the reactor, and the reactor outlet, and the reactor middle temperature was controlled by a high frequency induction heating system.

While adjusting the intermediate temperature of the high frequency induction heating pyrolysis reactor to 1,000 ° C., a gas mixture having a concentration of nitrous oxide of 0.84% and nitrogen of 99.16% was supplied at a flow rate of 600 liter / hr. The supplied nitrous oxide-containing gas mixture was preheated in a heat exchanger using a high temperature decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor and heated up to 600 ° C. In the pyrolysis process, the temperature at the reactor outlet was measured at 1,052 ° C. The nitrous oxide of the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor was determined to be 287 ppm by GC. The NO _x analyzer was used to analyze nitrogen oxides such as nitrogen monoxide and nitrogen dioxide in the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor. The residence time of the nitrous oxide containing gas mixture of Example 1 was 1.3 seconds and the nitrous oxide decomposition rate was 96.6%.

<Examples 2-5>

In order to understand the effect of the pyrolysis temperature, the experiment was carried out with the same conditions as in Example 1 except for changing the internal temperature of the high frequency induction heating pyrolysis reactor.

The results of nitrous oxide decomposition effect (N ₂ O concentration 0.84%) of pyrolysis temperature are summarized in Table 3 below.

	Flow rate (liter / hr)	Residence time (seconds)	Pyrolysis reactor temperature (℃)		N2O concentration after decomposition (ppm)	N2O decomposition rate (%)
			Reactor set point	Reactor outlet
Example 1	600	1.3	1,000	1,052	287	96.6
Example 2			800	839	5,936	29.5
Example 3			900	960	2,792	66.8
Example 4			960	1,011	1,180	86.0
Example 5			1,020	1,073	89	98.94

Nitrogen oxides such as nitrogen monoxide and nitrogen dioxide of the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor were analyzed using the NO _x analyzer in Examples 2 to 5, but were not detected.

<Examples 6-9>

The experiment was carried out under the same conditions as in Example 5 except for changing the flow rate of the nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor in order to determine the influence of the residence time. The results of the nitrous oxide decomposition effect (N ₂ O concentration 0.84%) of the nitrous oxide-containing gas mixture residence time in the pyrolysis reactor are summarized in Table 4 below.

	Flow rate (liter / hr)	Residence time (seconds)	Pyrolysis reactor temperature (℃)		N 2 O concentration after decomposition (ppm)	N 2 O Degradation Rate (%)
			Reactor set point	Reactor outlet
Example 5	600	1.3	1,020	1,073	89	98.9
Example 6	200	3.9	1,020	1,054	6	99.9
Example 7	400	2.0	1,020	1,062	12	99.9
Example 8	800	0.98	1,020	1,083	226	97.3
Example 9	1,000	0.79	1,020	1,100	323	96.2

Nitrogen oxides such as nitrogen monoxide and nitrogen dioxide of the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor were analyzed using the NO _x analyzer in Examples 5 to 9, but were not detected.

<Examples 10-14>

While increasing the nitrous oxide concentration of the nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor to 4.74% (containing 95.26% nitrogen) and changing the flow rate of the nitrous oxide-containing gas mixture, the other conditions were the same as in Example 1. The experiment was performed.

The results of nitrous oxide decomposition effect (N ₂ O concentration 4.74%) of pyrolysis temperature are summarized in Table 5 below.

	Flow rate (liter / hr)	Residence time (seconds)	Pyrolysis reactor temperature (℃)		N 2 O concentration after decomposition (ppm)	N 2 O Degradation Rate (%)
			Reactor set point	Reactor outlet
Example 10	200	3.9	1,020	1,057	22	99.9
Example 11	400	2.0	1,020	1,060	86	99.8
Example 12	600	1.3	1,020	1,074	540	98.9
Example 13	800	0.98	1,020	1,088	1,100	97.7
Example 14	1,000	0.79	1,020	1,104	1,104	97.0

Nitrogen oxides such as nitrogen monoxide and nitrogen dioxide of the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor were analyzed using the NO _x analyzer in Examples 10 to 14, but were not detected.

<Example 15>

Except for changing the composition (N ₂ O / O ₂ / N ₂ /NO=4.7%/5.8%/89.0%/0.5%) of the nitrous oxide-containing gas mixture supplied to the high frequency induction heating pyrolysis reactor, The experiment was carried out in the same manner as in Example 11. The concentration and decomposition rate of nitrous oxide after pyrolysis were the same as in Example 11. As a result of analyzing the nitrogen oxides such as nitrogen monoxide and nitrogen dioxide of the decomposition gas mixture discharged from the high frequency induction heating pyrolysis reactor using NO _x analyzer, the concentration of nitrogen monoxide was not different before and after pyrolysis, and nitrogen dioxide and nitride oxide were not detected. Did.

<Description of the code>

101: first pyrolysis furnace

102: heat exchanger

103: second pyrolysis furnace

104: steam generator

201: heat exchanger

202: high frequency induction heating pyrolysis reactor

203: high frequency induction heating system

204, 206: Temperature indicator

205: temperature indicating controller

Claims (11)

1. In the high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture,

   Decomposing the nitrous oxide-containing gas mixture by using a high frequency induction heating pyrolysis reactor for decomposing the nitrous oxide-containing gas mixture and a high frequency induction heating system for heating the nitrous oxide-containing gas mixture in the high frequency induction heating pyrolysis reactor (step 1); And

   Recovering energy from the high temperature pyrolysis gas mixture passed through step 1 by using a heat exchanger (step 2); high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture.
2. The method of claim 1,

   The high frequency induction heating pyrolysis reactor is a high frequency induction coil is disposed outside,

   The high frequency induction coil is in the form of a copper tube, a cooling water is supplied inside the tube to cool the high frequency induction coil and supply a high frequency to the tube wall high frequency induction heating pyrolysis process of the gas mixture.
3. The method of claim 1,

   The high frequency induction heating pyrolysis reactor is made of a metal material which can be used at a temperature of 1,000 ° C. or higher, and in particular, a high frequency induction heating pyrolysis process of a nitrous oxide-containing gas mixture including a high frequency induction pyrolysis reactor manufactured using Inconel.
4. The method of claim 1,

   Filling material is filled in the high frequency induction heating pyrolysis reactor, wherein the filling material is made of at least one of metal, ceramic and aluminum nitride, the diameter of the filling material is 3 to 30mm, and the filling material is made of metal The material of the pyrolysis reactor is a high frequency induction heating pyrolysis process of nitrous oxide containing gas mixture, characterized in that it comprises Inconel (Inconel).
5. The method of claim 1,

   Diameter (D) of the high frequency induction heating pyrolysis reactor is 0.5 to 20cm, the length (L) of the reactor is a high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture satisfying that the L / D value of 5 to 100.
6. The method of claim 1,

   The high frequency induction heating system includes a high frequency generator for generating a high frequency, a cooling system for cooling the high frequency generator and the high frequency induction coating, and a temperature control system for controlling a temperature of the high frequency induction heating pyrolysis reactor. High frequency induction pyrolysis process of nitrous oxide containing gas mixture, characterized in that the high frequency generated in the 3 ~ 30MHz.
7. The method of claim 1,

   The nitrous oxide-containing gas mixture supplied to the high-frequency induction heating pyrolysis reactor for pyrolysis contains at least one impurity of oxygen, nitrogen, nitride, sulfide and other pollutants, and pyrolysis efficiency is not affected by the concentration of the impurity. High frequency induction heating pyrolysis process of nitrous oxide containing gas mixture, characterized in that not.
8. The method of claim 1,

   The high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture, characterized in that the internal temperature of the high frequency induction heating pyrolysis reactor is maintained at 800 to 1,200 ℃.
9. The method of claim 1,

   The high frequency induction heating pyrolysis process of the nitrous oxide containing gas mixture, characterized in that the pressure of the high frequency induction heating pyrolysis reactor.
10. The method of claim 1,

    The residence time of the nitrous oxide-containing gas mixture in the high frequency induction pyrolysis reactor depends on the temperature and the pressure in the high frequency induction pyrolysis reactor, which is 0.5 to 5 seconds based on the conditions of 1 atm and 25 ° C. High frequency induction heating pyrolysis process of gas mixture.
11. The method of claim 1,

    The heat exchanger preheats the nitrous oxide-containing gas mixture supplied to the high frequency induction pyrolysis reactor using the high temperature pyrolysis gas mixture passed through step 1 to recover energy from the high temperature pyrolysis gas mixture passed through step 1. High frequency induction heating pyrolysis step of nitrous oxide containing gas mixture.

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