Methane removal device and operation method thereof

Abstract

The present invention relates to a methane removal device and an operation method thereof and, more specifically, to a methane removal device and an operation method thereof, wherein the ability to remove methane is improved by using nitrogen monoxide as a medium, and methane can be stably removed by using a non-noble metal-based catalyst. According to an embodiment of the present invention, a catalyst device necessary for satisfying the regulations for various internal combustion engines using natural gas as fuel can be provided to both revitalize the relevant industrial field and improve the problem of global warming. In addition, according to an embodiment of the present invention, it is possible to solve price problems and the like of conventional exhaust gas reduction devices, which have relied on noble metal catalysts, for removing hydrocarbons.

Description

Methane removal device and its operation method

[0001] The present invention relates to a methane removal device and an operating method thereof, and more particularly, to a methane removal device and an operating method thereof, which improves methane removal ability by using nitrogen monoxide as a medium and can stably remove methane by using a catalyst such as a non-precious metal or metal.

[0002]

[0003] To solve the problems of environmental pollution and global warming, development of engines using 'diesel' or 'natural gas' as fuel is underway.

[0004] In particular, for large engines exceeding 1MW, "mixed-fuel" engines that mix natural gas with diesel to induce ignition are gaining attention, rather than engines powered solely by natural gas. This approach can reduce carbon dioxide emissions and is being evaluated as a progressively strengthened carbon emissions reduction strategy.

[0005] However, in order to complete the above technology, a methane oxidation catalyst in which the removal reaction proceeds according to the following reaction scheme 1 is required.

[0006] Reaction equation 1: CH4+ 2O2→ CO2+ 2H2O, calorific value 812 kJ / mol

[0007] While methane emissions are negligible when diesel fuel is used solely, unburned methane is emitted when methane is mixed with other fuels, and its global warming potential is 30 times that of carbon dioxide. Therefore, the incomplete combustion of alternative fuels, blended with the goal of reducing carbon dioxide emissions, can mitigate this effect. Methane is the most stable hydrocarbon, and its oxidation and removal pose technical challenges. Furthermore, the challenge of simultaneously meeting the toxicity barrier of sulfur dioxide (SO2) contained in combustion exhaust gas must be overcome, making this area an unfinished technical area.

[0008] It is known that catalysts that support (or ion-exchange) palladium or palladium and platinum simultaneously on high-surface-area metal oxides (such as gamma-alumina) exhibit excellent methane oxidation performance. In particular, palladium catalysts in which an active material is supported or ion-exchanged on an acidic support such as an aluminosilicate or zeolite with a high silica-to-aluminum ratio have been disclosed. However, sufficient methane oxidation capacity has not yet been achieved under sulfur dioxide-containing conditions, and therefore, considerable efforts are required to overcome this problem. When natural gas and diesel fuel are mixed, especially when marine fuel is mixed and combusted, the composition of the exhaust gas (under steady-state operating conditions) shows that when marine fuel with a sulfur content of 0.5% (3% co-combustion) is mixed with natural gas, the sulfur dioxide concentration reaches 7.5 ppm. Under these conditions, the methane oxidation capacity of palladium-based catalysts is significantly reduced.

[0009] Therefore, it is necessary to develop a low-cost device that eliminates the influence of sulfur dioxide in methane removal devices, and the present invention presents a solution to this.

[0010]

[0011] The present invention has been devised to solve the above-mentioned problem, and one embodiment of the present invention provides a methane removal device with improved methane removal ability using nitrogen monoxide as a medium.

[0012] In addition, another embodiment of the present invention provides a method for operating a methane removal device.

[0013] The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0014]

[0015] As a technical means for achieving the aforementioned technical task, one aspect of the present invention is,

[0016] A methane removal device is provided, characterized in that it comprises: an inlet section containing a reaction gas; a methane removal section containing a catalyst layer that oxidizes methane using nitrogen oxide (NOx) as a medium; and an outlet section containing a purification gas.

[0017] The above reaction gas may be characterized by including nitrogen oxides (NOx), oxygen, and methane.

[0018] The catalyst layer for oxidizing the methane may be characterized by including a catalyst including a metal oxide.

[0019] The above nitrogen oxide (NOx) may be characterized as nitrogen monoxide.

[0020] The metal may be characterized by including one or more of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir).

[0021] The oxide of the metal may be supported on a support, and the support may be characterized by including at least one of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon.

[0022] The oxide of the above metal may be characterized in that it is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the catalyst.

[0023] The above catalyst may be characterized by being coated on a honeycomb structure.

[0024] The above catalyst may be characterized in that 10 to 200 g of catalyst is coated on 1 L of the honeycomb structure.

[0025] The above honeycomb structure may be characterized by at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

[0026] Another aspect of the present invention is:

[0027] A method for operating a methane removal device is provided, characterized by including: a step of contacting a reaction gas with a methane removal unit including a catalyst layer that oxidizes methane; and a step of discharging a purified gas through an outlet after a methane oxidation reaction in the methane removal unit.

[0028] The above reaction gas may be characterized by including nitrogen oxides (NOx), oxygen, and methane.

[0029] The catalyst layer for oxidizing the methane may be characterized by including a catalyst including a metal oxide.

[0030] The above nitrogen oxide (NOx) may be characterized as nitrogen monoxide.

[0031] The metal may be characterized by including one or more of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir).

[0032] The oxide of the metal may be supported on a support, and the support may be characterized by including at least one of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon.

[0033] The oxide of the above metal may be characterized by being manufactured by including 0.1 to 10 parts by weight relative to 100 parts by weight of the catalyst.

[0034] The above catalyst may be characterized by being manufactured by coating a honeycomb structure.

[0035] The above catalyst may be characterized in that it is manufactured by coating 10 to 200 g of the catalyst per 1 L of the honeycomb structure.

[0036] The above honeycomb structure may be characterized by at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

[0037]

[0038] According to an embodiment of the present invention, a catalyst device necessary for satisfying regulations of various internal combustion engines using natural gas as fuel can be provided, thereby revitalizing the relevant industrial field and improving the problem of global warming at the same time.

[0039] In addition, according to one embodiment of the present invention, it is possible to solve the price problem of conventional exhaust gas reduction devices for hydrocarbon removal that depend on precious metal catalysts.

[0040] The effects of the present invention are not limited to the above-described effects, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention.

[0041]

[0042] Figure 1 is a configuration diagram of a methane removal device according to one embodiment of the present invention.

[0043] Figure 2 is a graph showing the methane removal rate using an iron-supported catalyst (Fe / ZSM5) on zeolite according to one embodiment of the present invention.

[0044] Figure 3 is a graph showing the methane removal rate according to the concentration of nitrogen monoxide among the reactants in an iron-supported zeolite catalyst according to one embodiment of the present invention.

[0045] Figure 4 is a graph showing the results of a methane removal reaction using an iron ion exchange zeolite catalyst according to one embodiment of the present invention.

[0046] Figure 5 is a graph showing the results of a methane removal reaction using a catalyst simultaneously supporting iron and copper on zeolite according to one embodiment of the present invention.

[0047] Figure 6 is a graph showing the results of a methane removal reaction using a simultaneous iron and copper ion exchange catalyst in zeolite according to one embodiment of the present invention.

[0048] Figure 7 is a graph showing the results of a methane removal reaction using a vanadium-supported catalyst on zeolite according to one embodiment of the present invention.

[0049] Figure 8 is a graph showing the results of a methane removal reaction using a vanadium-supported catalyst on titanium dioxide according to one embodiment of the present invention.

[0050] Figure 9 is a graph showing the results of a methane removal reaction using an iron-supported catalyst on a silica-alumina support according to one embodiment of the present invention.

[0051] Figure 10 is a graph showing the results of a methane removal reaction using an iron-supported catalyst on a tungsten oxide support according to one embodiment of the present invention.

[0052] Figure 11 is a graph showing the results of a methane removal reaction in a methane removal device using iron oxide as a catalyst according to one embodiment of the present invention.

[0053] Figure 12 is a graph showing the results of a methane removal reaction in a methane removal device using vanadium oxide as a catalyst according to one embodiment of the present invention.

[0054] Figure 13 is a graph showing the results of a methane removal reaction in a methane removal device using a Co-Mo / ZSM5 catalyst according to one embodiment of the present invention.

[0055] Figure 14 is a graph showing the results of a methane removal reaction in a methane removal device using a Fe-Mn-Ce catalyst according to one embodiment of the present invention.

[0056] Figure 15 is a graph showing the results of a methane removal reaction in a methane removal device using a Ni-Mo / ZSM5 catalyst according to one embodiment of the present invention.

[0057]

[0058] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0059]

[0060] Example 1: Preparation of Fe / ZSM5 catalyst

[0061] Fe(NO3)3·9H2O was used as an iron precursor, and zeolite (ZSM5, manufacturer: Jisimtech Co., Ltd.) was used as a support. The active metal was supported by the initial wetting method with an iron content of 1 wt% based on the support. The powder catalyst was completed by drying at 105°C for 12 hours and calcining at 600°C for 4 hours.

[0062] The manufactured powder catalyst was coated on a 400 cpsi cordierite honeycomb specimen (diameter 16 mm, height 5.2 mm, volume 0.91 ml) at a coating amount of 132 g / L, and then dried and calcined to complete the process.

[0063]

[0064] Example 2: Preparation of Fe / ZSM5 catalyst by ion exchange method

[0065] First, zeolite was converted to ammonium foam, and second, ion exchange of the active metal was performed. At this time, heating was performed in the range of 50 to 70℃ to minimize the ion exchange time. After ion exchange, hydrothermal washing was repeated several times to remove unreacted ions, and a powder catalyst was manufactured through drying and calcination. The manufactured powder catalyst was manufactured in the same manner as the honeycomb coating process of Example 1, but the powder catalyst coating amount was 160 g / L.

[0066]

[0067] Example 3: Preparation of Cu-Fe / ZSM5 catalyst

[0068] Copper precursor Cu(NO3)2·3H2O, iron precursor Fe(NO3)3·9H2O, and zeolite as a support were used, and the active metals were supported by the initial wetting method with the contents of copper and iron each being 1 wt% relative to the support. The powder catalyst was completed by drying at 105°C for 12 hours and calcining at 600°C for 4 hours.

[0069] The manufactured powder catalyst was coated at 140 g / L on a 400 cpsi cordierite honeycomb specimen (diameter 16 mm, height 5.2 mm, volume 0.91 ml), and then dried and calcined to complete the process.

[0070]

[0071] Example 4: Preparation of Cu-Fe / ZSM5 catalyst by ion exchange method

[0072] The same procedure as the ion exchange method of Example 2 was followed, but copper precursor and iron precursor were used as the active metals, and the powder catalyst coating amount was 130 g / L relative to the zeolite support.

[0073]

[0074] Example 5: Preparation of V / ZSM5 catalyst

[0075] NH4VO3 was used as a vanadium precursor and zeolite as a support, and the active metal was supported by the initial wetting method with a vanadium content of 2 wt% relative to the support. The powder catalyst was completed by drying at 105°C for 12 hours and calcining at 600°C for 4 hours.

[0076] The manufactured powder catalyst was coated on a 400 cpsi cordierite honeycomb specimen (diameter 16 mm, height 5.2 mm, volume 0.91 ml) at a coating amount of 125 g / L, and then dried and calcined to complete the process.

[0077]

[0078] Example 6: Preparation of V / TiO2 catalyst

[0079] NH4VO3 was used as a vanadium precursor and titanium dioxide (TiO2) was used as a support, and the active metal was supported by the initial wetting method with a vanadium content of 5 wt% based on the support. The powder catalyst was completed by drying at 105℃ for 12 hours and calcining at 600℃ for 4 hours. The manufactured powder catalyst was coated on a 400 cpsi cordierite honeycomb specimen (diameter 16 mm, height 5.2 mm, volume 0.91 ml) at a coating amount of 134 g / L, and then dried and calcined to complete the catalyst.

[0080]

[0081] Example 7: Preparation of Fe / SA catalyst

[0082] A powder catalyst was prepared by loading the iron content of 2 wt% on a silica-alumina support using the initial wetting method, drying at 105°C for 12 hours, and calcining at 600°C for 4 hours. The prepared powder catalyst was coated on a monolith (152 g / L), followed by drying and calcination to complete the process.

[0083]

[0084] Example 8: Preparation of Fe / WO33 catalyst

[0085] A powder catalyst was prepared by loading a tungsten oxide support with an iron content of 1 wt% using the initial wetting method, drying at 105°C for 12 hours, and calcining at 600°C for 4 hours. The prepared powder catalyst was coated on a monolith (159 g / L), followed by drying and calcination to complete the process.

[0086]

[0087] Example 9: Preparation of iron oxide (FeOx) catalyst

[0088] Iron nitrate was calcined in an air atmosphere at 500℃ for 4 hours to produce iron oxide (FeOx) powder, and the produced powder was coated (95 g / L) on a monolith, followed by drying and calcination to complete the process.

[0089]

[0090] Example 10: Preparation of vanadium oxide (VOx) catalyst

[0091] Ammonium metavanadate is calcined in an air atmosphere at 600℃ for 4 hours to produce vanadium oxide (VO x ) was manufactured, and the manufactured powder was coated on a honeycomb (107 g / L), and then dried and fired to complete the process.

[0092]

[0093] Example 11: Preparation of Co-Mo / ZSM5 catalyst

[0094] Cobalt precursor Co(NO3)2·6H2O, molybdenum precursor (NH4)6Mo7O 24 ·4H2O, zeolite was used as the support, and the cobalt and molybdenum contents were each 5 wt% relative to the support, supported by the initial wetting method, dried at 105°C for 12 hours, and calcined at 600°C for 4 hours to produce a powder catalyst. The produced powder catalyst was coated on a honeycomb (128 g / L), and then dried and calcined to complete the process.

[0095]

[0096] Example 12: Preparation of Fe-Mn-Ce catalyst

[0097] Iron precursor Fe(NO3)3·9H2O, manganese precursor Mn(NO3)2.6H2O, and cerium precursor Ce(NO3)3.6H2O were used. The nitrates of each precursor were dissolved at a concentration of 1 mol while maintaining the weight ratio, and ammonia water was added dropwise to lower the pH to 8.5 or lower to form a precipitate. Without a separate post-treatment, a powder catalyst was manufactured by filtering, drying (105°C, 24 hours), and calcining (600°C, 4 hours). Honeycomb coating was performed in the same manner as in Example 1, but the coating amount was 106 g / L, and then drying and calcining were performed to complete the coating.

[0098]

[0099] Example 13: Preparation of Ni-Mo / ZSM5 catalyst

[0100] Nickel precursor Ni(NO3)2·6H2O, molybdenum precursor (NH4)6Mo7O 24 ·4H2O and zeolite were used as a support, and nickel and molybdenum contents were each 5 wt% relative to the support, and the catalyst was supported by the initial wetting method, dried at 105°C for 12 hours, and calcined at 600°C for 4 hours to produce a powder catalyst. The produced catalyst was coated on a honeycomb (128 g / L), and then dried and calcined to complete the process.

[0101]

[0102] Table 1 below lists catalysts manufactured according to one embodiment of the present invention, Table 2 lists metal oxide precursors used in the manufacture of the catalyst, and Table 3 lists supports used in the manufacture of the catalyst.

[0103] Example No. Powder catalyst composition (indicated) Content Powder catalyst coating amount (g / liter) Manufacturing method 1 Fe[1] / ZSM5 Fe 1 wt% 132 Initial wetting method Support 2 Fe[1] / ZSM5 Fe 1 wt% 132 Initial wetting method Support 3 Fe[1]-ZSM5 Fe 1 wt% 160 Ion exchange method 4 Cu[1]-Fe[1] / ZSM5 Cu, Fe each 1 wt% 140 Initial wetting method Support 5 Cu[1]-Fe[1]-ZSM5 each 1 wt% 130 Ion exchange method 6 V[2] / ZSM5 V 2 wt% 125 Initial wetting method Support 7 V[2] / TiO2 V 5 wt% 134 Initial wetting method Support 8 Fe[2] / S.AFe 2 wt% 152 Initial wetting method Supported 9Fe[1] / WO3Fe 1wt%159 Initial wetting method Supported 10FeO x Thermal decomposition of 100 wt% 95% iron nitrate 11VO x Oxide 100 wt% 107 Ammonium metavanadate thermal decomposition 12 Co[5]-Mo[5] / ZSM5 Co, Mo each 5 wt% 128 Initial wetting method Support 13 Fe[4]-Mn[4]-Ce

[0092] Fe, Mn each 4 wt% 1063 Component coprecipitation 14 Ni[5]-Mo[5] / ZSM5 Ni, Mo each 5 wt% 128 Initial wetting method Support

[0104] Material precursor (notation) Manufacturer characteristics CuCu(NO3)2·3H2OJunsei ChemicalFeFe(NO3)3·9H2OJunsei ChemicalMnMn(NO3)2·6H2OJunsei ChemicalCoCo(NO3)2.6H2OJunsei ChemicalNiNi(NO3)2.6H2OSigma AldrichCeCe(NO3)3.6H2OSamjeon ChemicalMo(NH4)6Mo7O 24 ·4H2OYakuri pure ChemicalVNH4VO3Sigma Aldrich

[0105] Material precursor (notation) Manufacturer characteristics Titanium dioxide TiO2 Alfa Aesar Anatase Zeolite ZSM5 Jisim Tech Co., Ltd. Si / Al=35 Silica Alumina Silica Alumina Sigma Aldrich Si / Al=8

[0106]

[0107] Experimental Example 1: Measurement of methane conversion rate in the presence or absence of nitrogen monoxide (NO).

[0108] Using the catalyst manufactured in Example 1, the dependence of methane conversion rate on the presence or absence of nitrogen monoxide during methane oxidation was measured. As a result of the experiment, in the case of the condition of including 100 ppm of nitrogen monoxide in the reaction gas, as shown in (a) of Fig. 2, the methane conversion rate was 50% (LOT, T 50 ) obtained an oxidation power of 555.6℃ and 90% of 590℃. Considering that the catalytic performance under the nitrogen oxide containing condition is at a level where even LOT definition is impossible under SO2 containing conditions for catalysts developed so far, it can be seen that it is an outstanding performance.

[0109] On the other hand, under conditions without nitrogen monoxide, the methane conversion rate was found to be at a maximum of 5.5°C at 615°C, regardless of the presence or absence of sulfur dioxide and moisture, indicating almost no oxidation capacity. In other words, the methane oxidation capacity can be assessed to be at a level where it is almost nonexistent when nitrogen monoxide is not included.

[0110] According to the above results, it can be seen that the presence or absence of nitrogen monoxide in the reactants of the catalyst of Example 1 is a decisive factor in the methane conversion rate.

[0111] In addition, the effects of nitrogen monoxide inclusion were compared under conditions including 'moisture and sulfur dioxide', which are known to reduce performance in catalytic reactions. Comparing (b) and (d) of Fig. 2, it can be seen that the effect of nitrogen monoxide on methane oxidation is far superior even under conditions including pollutants (H2O, SO2).

[0112]

[0113] Experimental Example 2: Measurement of changes in methane conversion rate according to nitrogen monoxide concentration

[0114] The change in methane conversion rate according to nitrogen monoxide concentration was measured using the catalyst manufactured in Example 1. The reaction temperature was fixed at 540°C, and the reaction gases were commonly maintained as 1,000 ppm methane, 10% O2, 10 ppm SO2, and 2% water vapor, and the methane conversion rate was measured under each condition of nitrogen monoxide concentration of 0, 50, 100, 200, and 300 ppm.

[0115] As summarized in Fig. 3, the measurement results showed that as the nitrogen monoxide concentration increased, the methane conversion rate also gradually increased, converging to the maximum conversion rate in the 200 ppm range. In other words, the mixing concentration of nitrogen monoxide is sufficiently effective when it is 20% or more compared to methane, and the contribution of nitrogen monoxide decreases in the lower range. However, even in the 50-100 ppm range, the methane oxidation power increased by 25-35%. These results show that the effect of nitrogen monoxide in the methane oxidation reaction is far superior.

[0116]

[0117] Experimental Example 3: Measurement of methane conversion rate

[0118] The methane oxidation reaction was carried out using the catalyst manufactured in Example 1. As a result of the measurement, as shown in (a) of Fig. 4, the methane conversion rate of 50% was achieved at 540°C (T 50 ), the 90% removal temperature showed a performance of 590℃. Compared to (D) of Fig. 4, which does not contain nitrogen oxides, it can be seen that nitrogen monoxide has an absolute influence on the methane oxidation power.

[0119] On the other hand, under conditions without nitrogen monoxide, the removal power is very low, with a methane conversion rate of 22% at 615°C. In other words, it can be seen that the methane conversion rate increases significantly when nitrogen monoxide is included.

[0120]

[0121] Experimental Example 4: Measurement of Methane Conversion Rate

[0122] The methane removal power was measured according to the inclusion of nitrogen monoxide using the catalyst manufactured in Example 3. As a result of the measurement, as shown in (a) of Fig. 5, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 484.2℃(T 50 ), 90% removal performance (T 90 ) obtained 512℃.

[0123] On the other hand, when nitrogen monoxide was not included, methane conversion rates of 50% and 90% could not be confirmed in the test temperature range, and a conversion rate of 30.5% was shown at 615℃.

[0124] From the above results, it can be seen that the methane oxidation ability of the Cu-Fe / HZSM5 catalyst is absolutely affected by the presence or absence of nitrogen monoxide.

[0125]

[0126] Experimental Example 5: Measurement of Methane Conversion Rate

[0127] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 4. As a result of the measurement, as shown in (a) of Fig. 6, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 560℃(T 50 ), 90% removal performance (T 90 ) obtained 602℃.

[0128] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 6, the methane conversion rate is 50% (T 50 ), 90%(T 90 ) It was impossible to reach the removal performance, which was at the level of 26.5% at 615℃.

[0129] From the above results, it can be seen that nitrogen monoxide has an absolute effect on the methane oxidation ability of the Cu-Fe-ZSM5 catalyst.

[0130]

[0131] Experimental Example 6: Measurement of Methane Conversion Rate

[0132] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 5. As a result of the measurement, as shown in (a) of Fig. 7, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 566℃(T 50 ), 90% removal performance (T 90 ) obtained 610℃.

[0133] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 7, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. At the highest measured temperature of 615℃, the conversion rate was found to be 26%.

[0134] From the above results, it can be seen that nitrogen monoxide has an absolute effect on the methane oxidation ability of the V / ZSM5 catalyst.

[0135] From the above results, it can be seen that if nitrogen oxides are included in the methane removal process, the desired purpose can be achieved even if the expensive ion exchange process is replaced with an impregnation method, thereby providing a competitive catalytic reactor.

[0136]

[0137] Experimental Example 7: Measurement of Methane Conversion Rate

[0138] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 6. As a result of the measurement, as shown in (a) of Fig. 8, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 570℃(T 50 ), 90% removal performance (T 90 ) obtained 610℃.

[0139] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 8, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. It showed a level of 5.1% at the highest measured temperature of 615℃.

[0140] The above results demonstrate that V / TiO2, like other catalysts, exhibits a significant influence of nitrogen monoxide on methane oxidation. This demonstrates that the catalyst is not limited to zeolites specialized as transition metal supports, but can be expanded to encompass the range of commercially available titanium dioxide.

[0141] From the above results, it can be seen that in the methane removal process, when nitrogen oxides are included, it is possible to configure a catalytic reactor using various inexpensive transition metal and generalized metal oxide supports.

[0142]

[0143] Experimental Example 8: Measurement of Methane Conversion Rate

[0144] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 7. As a result of the measurement, as shown in (a) of Fig. 9, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 572℃(T 50 ), 90% removal performance (T 90 ) obtained 608℃.

[0145] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 9, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. It showed a level of 4.1% at the highest measured temperature of 615℃.

[0146] From the above results, it can be seen that nitrogen monoxide has an absolute influence on the methane oxidation ability of the Fe / SA catalyst.

[0147] From the above results, it can be seen that when nitrogen oxides are included in the methane removal process, it is possible to configure a catalytic reactor that extends to the range of inexpensive various transition metals and general inexpensive metal oxide supports, especially titanium dioxide.

[0148]

[0149] Experimental Example 9: Measurement of Methane Conversion Rate

[0150] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 8. As a result of the measurement, as shown in (a) of Fig. 10, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 570℃(T 50 ), 90% removal performance (T 90 ) obtained 608℃.

[0151] On the other hand, when nitrogen monoxide was not included, the conversion rate was less than 4% throughout the entire measurement temperature range, as shown in (b) of Fig. 10.

[0152] From the above results, it can be seen that nitrogen monoxide has an absolute effect on the methane oxidation ability of the Fe[1] / WO3 catalyst.

[0153] From the above results, it can be seen that when nitrogen oxides are included in the methane removal process, it is possible to configure a catalytic reactor that extends to various inexpensive transition metals and general inexpensive metal oxide supports, especially the WO3 region.

[0154]

[0155] Experimental Example 10: Measurement of Methane Conversion Rate

[0156] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 9. As a result of the measurement, as shown in (a) of Fig. 11, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 575℃(T 50 ), 90% removal performance (T 90 ) was obtained at 605℃.

[0157] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 11, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. It showed a level of 5.6% at the highest measured temperature of 615℃.

[0158] From the above results, it can be seen that nitrogen monoxide has an absolute influence on the methane oxidation ability of the iron oxide catalyst.

[0159] Notably, methane oxidation was achieved using metal oxides alone, even without high-surface-area supports. This means that when nitrogen oxides are included in a methane removal device, extremely inexpensive iron oxides can be used as catalysts. This demonstrates the feasibility of constructing an ultra-low-cost catalytic reactor.

[0160]

[0161] Experimental Example 11: Measurement of Methane Conversion Rate

[0162] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 10. As a result of the measurement, as shown in (a) of Fig. 12, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 564℃(T 50 ), 90% removal performance (T 90 ) was obtained at 605℃.

[0163] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 12, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. A maximum conversion rate of 3.6% was observed over the measurement temperature range.

[0164] From the above results, it can be seen that in the presence of nitrogen monoxide, methane can be effectively removed using vanadium oxide, a low-cost material, as a catalyst. In other words, according to the present invention, it is possible to construct an ultra-low-cost purification device.

[0165]

[0166] Experimental Example 12: Measurement of Methane Conversion Rate

[0167] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 11. As a result of the measurement, as shown in (a) of Fig. 13, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 550℃(T 50 ), 90% removal performance (T 90 ) obtained 603℃.

[0168] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 13, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. A maximum conversion rate of 7.1% was observed over the measurement temperature range.

[0169] Based on the above results, it can be confirmed that the methane removal temperature can be lowered when using a multi-component transition metal catalyst compared to a single component when nitrogen monoxide is present. In other words, according to the present invention, it is possible to construct a low-cost purification device using a transition metal catalyst.

[0170]

[0171] Experimental Example 13: Measurement of Methane Conversion Rate

[0172] The methane removal power was measured according to the inclusion of nitrogen monoxide using the catalyst manufactured in Example 12. As a result of the measurement, as shown in (a) of Fig. 14, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 560℃(T 50 ), 90% removal performance (T 90 ) was obtained at 590℃.

[0173] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 14, the methane conversion rate is 50% (T 50 ), it was impossible to reach 90%, and the maximum conversion rate was 5.0% over the measurement temperature range.

[0174] The above results demonstrate that methane can be effectively reduced in the presence of nitrogen monoxide using a transition metal catalyst, excluding expensive, high-surface-area supports (e.g., zeolite, silica alumina, titanium dioxide). Therefore, it is evident that the construction of a low-cost purification device using a transition metal catalyst is feasible.

[0175]

[0176] Experimental Example 14: Measurement of Methane Conversion Rate

[0177] The methane removal power was measured according to the presence or absence of nitrogen monoxide using the catalyst manufactured in Example 13. As a result of the measurement, as shown in (a) of Fig. 15, when nitrogen monoxide was included, the methane conversion rate was 50% (T 50 ) is 555℃(T 50 ), 90% removal performance (T 90 ) obtained 603℃.

[0178] On the other hand, when nitrogen monoxide is not included, as in (b) of Fig. 15, the methane conversion rate is 50% (T 50 ), a 90% conversion rate could not be achieved. Removal performance could not be achieved with a maximum conversion rate of 2.4% over the measurement temperature range.

[0179] Based on the above results, it was confirmed that, in the presence of nitrogen monoxide, the methane removal temperature can be lowered when using a multi-component transition metal catalyst compared to a single-component one. In particular, the desired effect can be achieved using nickel, a relatively inexpensive transition metal. According to the present invention, it can be seen that the construction of a purification device using an inexpensive transition metal catalyst is possible.

[0180]

[0181] Hereinafter, the present invention will be described in more detail. However, the present invention may be implemented in many different forms, and the present invention is not limited to the embodiments described herein, but is defined solely by the claims set forth below.

[0182] Additionally, the terminology used herein is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. Throughout the specification of the present invention, the term "including" or "comprising" a component does not exclude other components, but rather implies the inclusion of other components, unless specifically stated otherwise.

[0183] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not exclude other components, but rather implies that it may include other components, unless otherwise specifically stated.

[0184] The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0185]

[0186] The first aspect of this article is,

[0187] A methane removal device is provided, characterized by including an inlet section containing a reaction gas; a methane removal section containing a catalyst layer that oxidizes methane using nitrogen oxide (NOx) as a medium; and an outlet section containing a purification gas.

[0188]

[0189] Hereinafter, a methane removal device according to the first aspect of the present invention will be described in detail.

[0190]

[0191] In one embodiment of the present invention, the reaction gas may include nitrogen oxides (NOx), oxygen, and methane, and preferably, the nitrogen oxides (NOx) may be nitrogen monoxide. To obtain excellent methane oxidation capacity, nitrogen oxides are required in the inlet gas along with oxygen and methane components. This allows the formation of nitrogen dioxide (NO2), a powerful oxidizing agent, and promotes the oxidation of intermediates (CHO compounds) generated in the partial oxidation of methane.

[0192] The methanogenesis reaction is usually expressed as shown in reaction scheme 1, but if it is approached as a reaction that passes through an intermediate stage (CHO compound), the problem of sulfur dioxide can be solved while achieving the desired goal with a low-cost transition metal that excludes precious metals.

[0193] In one embodiment of the present invention, the catalyst layer for oxidizing methane may include a catalyst including a metal oxide.

[0194] In one embodiment of the present invention, the nitrogen oxide (NOx) may be characterized as nitrogen monoxide.

[0195] In one embodiment of the present invention, the metal may include one or more of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir), and preferably, may include one or more of iron, copper, vanadium, and molybdenum.

[0196] In one embodiment of the present invention, the metal oxide is supported on a support, and the support may include one or more of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon, preferably one or more of titanium oxide, zeolite, silicon oxide, and aluminum oxide, and more preferably one or more of titanium dioxide, zeolite, and silica alumina.

[0197] In one embodiment of the present invention, the metal oxide may be included in an amount of 0.1 to 10 parts by weight relative to 100 parts by weight of the catalyst. If the metal oxide is less than 0.1 parts by weight relative to 100 parts by weight of the catalyst, the amount of metal oxide may be too small to allow sufficient methane oxidation, and if it exceeds 10 parts by weight, the supported metal may plug the pores of the support, thereby reducing the methane removal rate.

[0198] In one embodiment of the present invention, the catalyst may be coated on a honeycomb structure.

[0199] In one embodiment of the present invention, the catalyst may be characterized in that 10 to 200 g of catalyst is coated per 1 L of the honeycomb structure. If less than 10 g of catalyst is coated per 1 L of the honeycomb structure, the methane oxidation reaction does not sufficiently occur, resulting in a decrease in efficiency. If more than 200 g is coated, the excessive amount of catalyst may cause the catalyst to detach from the honeycomb surface due to a halving of its adhesion, which is not preferable in terms of durability.

[0200] In one embodiment of the present invention, the honeycomb structure may be characterized by being made of at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

[0201]

[0202] The second aspect of the original text is,

[0203] A method for operating a methane removal device is provided, characterized by including: a step of contacting a reaction gas with a methane removal unit including a catalyst layer that oxidizes methane; and a step of discharging a purified gas through an outlet after a methane oxidation reaction in the methane removal unit.

[0204]

[0205] Detailed explanations of parts that overlap with the first aspect of the present application have been omitted, but the explanations of the first aspect of the present application may be applied equally even if the explanations are omitted in the second aspect.

[0206]

[0207] Hereinafter, the method of operating a methane removal device according to the second aspect of the present invention will be described in detail.

[0208] In one embodiment of the present invention, the reaction gas may include nitrogen oxides (NOx), oxygen and methane, and preferably, the nitrogen oxides (NOx) may be nitrogen monoxide.

[0209] In one embodiment of the present invention, the catalyst layer may include a catalyst including a metal oxide.

[0210] In one embodiment of the present invention, the nitrogen oxide (NOx) may be characterized as nitrogen monoxide.

[0211] In one embodiment of the present invention, the metal may include one or more of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir), and preferably, may include one or more of iron, copper, vanadium, and molybdenum.

[0212] In one embodiment of the present invention, the metal oxide is supported on a support, and the support may include one or more of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon, preferably one or more of titanium oxide, zeolite, silicon oxide, and aluminum oxide, and more preferably one or more of titanium dioxide, zeolite, and silica alumina.

[0213] In one embodiment of the present invention, the metal oxide may be included in an amount of 0.1 to 10 parts by weight relative to 100 parts by weight of the catalyst. If the metal oxide is less than 0.1 parts by weight relative to 100 parts by weight of the catalyst, the amount of metal oxide may be too small to allow sufficient methane oxidation, and if it exceeds 10 parts by weight, the supported metal may cause porous plugging of the support, thereby reducing the reactivity.

[0214] In one embodiment of the present invention, the catalyst may be coated on a honeycomb structure.

[0215] In one embodiment of the present invention, the catalyst may be characterized in that 10 to 200 g of catalyst is coated per 1 L of the honeycomb structure. If less than 10 g of catalyst is coated per 1 L of the honeycomb structure, the methane oxidation reaction does not sufficiently occur, resulting in reduced efficiency. If more than 200 g of catalyst is coated, the weakening of adhesion may cause durability problems.

[0216] In one embodiment of the present invention, the honeycomb structure may be characterized by being made of at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

[0217]

[0218] The present invention relates to a methane removal device and an operating method thereof, and more particularly, to a methane removal device and an operating method thereof, which improves methane removal ability by using nitrogen monoxide as a medium and can stably remove methane by using a non-precious metal catalyst.

[0219] According to an embodiment of the present invention, a catalyst device necessary for satisfying regulations of various internal combustion engines using natural gas as fuel can be provided, thereby revitalizing the relevant industrial field and improving the problem of global warming at the same time.

[0220] In addition, according to one embodiment of the present invention, it is possible to solve the price problem of conventional exhaust gas reduction devices for hydrocarbon removal that depend on precious metal catalysts.

Claims

1. Inlet containing reaction gas; A methane removal unit including a catalyst layer that oxidizes methane using nitrogen oxides (NOx) as a medium; and A methane removal device, characterized by including an outlet including a purification gas.

2. In paragraph 1, A methane removal device, characterized in that the reaction gas includes nitrogen oxides (NOx), oxygen, and methane.

3. In paragraph 1, A methane removal device, characterized in that the catalyst layer comprises a catalyst including a metal oxide.

4. In paragraph 1, A methane removal device, characterized in that the above nitrogen oxide (NOx) is nitrogen monoxide.

5. In paragraph 3, A methane removal device characterized in that the metal includes at least one of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir).

6. In paragraph 3, The oxide of the above metal is in a form supported on a support, A methane removal device, characterized in that the support comprises at least one of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon.

7. In paragraph 3, A methane removal device, characterized in that the oxide of the metal is contained in an amount of 0.1 to 10 parts by weight relative to 100 parts by weight of the catalyst.

8. In paragraph 1, A methane removal device, characterized in that the above catalyst is coated on a honeycomb structure.

9. In paragraph 8, A methane removal device, characterized in that the catalyst is coated with 10 to 200 g of catalyst per 1 L of honeycomb structure.

10. In paragraph 8, A methane removal device, characterized in that the honeycomb structure is made of at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

11. A step of contacting a reaction gas with a methane removal unit including a catalyst layer that oxidizes methane; and a step of discharging a purified gas through an outlet after a methane oxidation reaction in the methane removal unit; A method for operating a methane removal device, characterized in that the above catalyst layer oxidizes methane using nitrogen oxide (NOx) as a medium.

12. In paragraph 11, A method for operating a methane removal device, characterized in that the reaction gas includes nitrogen oxides (NOx), oxygen, and methane.

13. In paragraph 11, A method for operating a methane removal device, characterized in that the catalyst layer includes a catalyst including a metal oxide.

14. In paragraph 11, A method for operating a methane removal device, characterized in that the above nitrogen oxide (NOx) is nitrogen monoxide.

15. In paragraph 11, A method for operating a methane removal device, characterized in that the metal includes at least one of copper (Cu), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), vanadium (V), molybdenum (Mo), tungsten (W), cerium (Ce), chromium (Cr), zinc (Zn), lanthanum (La), tin (Sn), antimony (Sb), niobium (Nb), ruthenium (Ru), palladium (Pd), platinum (Pt), and iridium (Ir).

16. In paragraph 11, The oxide of the above metal is in a form supported on a support, A method for operating a methane removal device, characterized in that the support comprises at least one of titanium oxide, zeolite, silicon oxide, aluminum oxide, cerium oxide, vanadium oxide, zirconium oxide, zinc oxide, lanthanum oxide, magnesium oxide, and activated carbon.

17. In paragraph 13, A method for operating a methane removal device, characterized in that the oxide of the metal is manufactured in an amount of 0.1 to 10 parts by weight relative to 100 parts by weight of the catalyst.

18. In paragraph 11, A method for operating a methane removal device, characterized in that the catalyst is manufactured by coating a honeycomb structure.

19. In paragraph 18, A method for operating a methane removal device, characterized in that the catalyst is manufactured by coating 10 to 200 g of catalyst per 1 L of a honeycomb structure.

20. In paragraph 18, A method for operating a methane removal device, characterized in that the honeycomb structure is made of at least one of silicon carbide, silicon nitride, cordierite, silicon carbide-cordierite, silica, alumina, silica-alumina, aluminum silicate, and aluminum titanate.

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