Combustible waste gas catalytic conversion system based on self-oxygen supply and application

Abstract

The invention belongs to the technical field of combustible gas catalysis, and particularly relates to a combustible waste gas catalytic conversion system based on self oxygen supply and application. The catalytic conversion system includes a housing; a flue gas inlet and a flue gas outlet are respectively formed in two ends of the shell; an oxygen supply device, a CO catalyst layer, a non-methane CH compound catalyst layer and an H2 and methane mixed catalyst layer are sequentially arranged in a shell of the catalytic conversion system in the direction from a flue gas inlet to a flue gas outlet. The oxygen supply device is used for generating oxygen, and an oxygen supply agent for generating the oxygen in the oxygen supply device comprises any one of NaClO3 or KClO3. The combustible waste gas catalytic conversion system is used for solving the problems that in the existing chemical production process, leaked flue gas treatment cost is high, efficiency is low, and the occupied area is large; the device has the advantages of high catalytic efficiency, compact structure, small occupied area, low production cost and maintenance cost and the like.

Description

Technical Field

[0001] This invention belongs to the field of combustible gas catalytic technology, specifically relating to a combustible waste gas catalytic conversion system based on self-oxygen supply and its application. Background Technology

[0002] The production processes of liquefied petroleum gas (LPG), methanol synthesis, acetylene synthesis, and coal chemical processes generate large amounts of flammable gases such as CO, H2, and CH compounds. These gases often contain little or no O2 (volume content <5%), posing a certain risk of leakage during production. If these flammable gases are not properly handled, they can cause fires, explosions, and other hazards, endangering people's lives and property.

[0003] In engineering, catalytic oxidation is often used to treat combustible gases, converting them into harmless substances such as CO2 and H2O through oxidation. However, catalytic oxidation requires a certain amount of O2, but in the aforementioned chemical production processes, high-concentration combustible gases often contain little or no O2, and their initial temperature is low. Currently, O2 is often added externally to provide the necessary O2 for the catalytic oxidation reaction. However, existing external O2 technologies typically involve adding compressed air or pure oxygen to the gas source. While these technologies provide some O2, the added compressed air or pure oxygen is often at a low temperature (generally around 25°C) and has fluidity, carrying away a significant amount of heat and thus lowering the temperature of the catalytic oxidation reaction. Therefore, industrial applications often require a heating system for these "oxygen sources." This technology increases the cost and size of the equipment used for treating flue gas. Therefore, there is an urgent need in industry for a low-cost, low-volume, low-oxygen environment catalytic oxidation device for purifying combustible gases.

[0004] For the treatment of high concentrations of combustible gases in anaerobic or low-oxygen environments, "A Thermal Oxidation Purification Device for Low-Temperature Methanol Washing Tail Gas from Crushed Coal" (Chinese Patent Application No. 201922485043.4) removes organic waste gas from the low-temperature methanol washing tail gas from crushed coal by employing multi-stage heat exchange and multi-stage oxidation purification methods. The thermal oxidation purification device includes a waste gas dilution system, an oxidation heat exchange system, an emission system, and a control system. The oxidation heat exchange system includes a catalytic oxidation bed and a thermal incinerator. While this method can remove organic gases from exhaust gas, it requires an additional heating device, increasing the cost and size of the exhaust gas treatment equipment. "A VOCs Waste Gas Catalytic Oxidation Equipment" (Chinese Patent, Application No. 201922485043.4) includes an exhaust pipe, flame arrester, catalytic fan, first heat exchanger, second heat exchanger, catalytic oxidation bed, exhaust gas pipeline, and flue. This device effectively utilizes high-temperature exhaust gas and achieves controllable temperature of the waste gas to be treated in the catalytic oxidation bed. However, it has a large footprint and high equipment cost. "Liquefied Petroleum Gas Desulfurization Organic Waste Gas Emission Reduction Technology" (paper, DOI: 10.3969) integrates the process by replacing factory air with oxygen and increasing raw material pretreatment. After implementation in a refining and chemical enterprise, the average volume fractions of oxygen and hydrocarbon components in the circulating gas were 9.7% and 21.7%, respectively, reducing organic waste gas in industrial flue gas. However, this method requires an additional oxygen supplementation device, increasing the equipment footprint and cost.

[0005] The aforementioned patents all report methods for treating high concentrations of flammable gases under anaerobic or low-oxygen conditions. However, existing treatment methods often require additional oxygen supply and heat exchange devices, resulting in large equipment footprints and high costs for flammable gas treatment. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a self-oxygenated combustible waste gas catalytic conversion system and its application. This catalytic conversion system uses a technology that couples an oxygen supply device with a high-performance catalyst to achieve an integrated oxygen supply and catalysis process. At the same time, it utilizes the heat generated by the catalytic reaction to enhance the catalytic performance of the catalyst, thereby improving waste gas treatment efficiency and reducing waste gas treatment costs.

[0007] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution:

[0008] A catalytic conversion system for combustible waste gas based on self-oxygenation, the catalytic conversion system comprising a shell; a flue gas inlet and a flue gas outlet are respectively provided at both ends of the shell;

[0009] Along the direction from flue gas inlet to flue gas outlet, an oxygen supply device, a CO catalyst layer, a non-methane CH compound catalyst layer, and a mixed catalyst layer of H2 and methane are sequentially arranged inside the shell of the catalytic conversion system.

[0010] The oxygen supply device is used to generate oxygen, and the oxygen supply agent used to generate oxygen in the oxygen supply device includes either NaClO3 or KClO3.

[0011] Furthermore, the oxygen supply device includes a thermally conductive and pressure-resistant housing, an oxygen supply agent contained in the thermally conductive and pressure-resistant housing, an ignition unit disposed at one end of the thermally conductive and pressure-resistant housing, and an oxygen outlet disposed at the other end of the thermally conductive and pressure-resistant housing;

[0012] The thermally conductive and pressure-resistant housing is made of carbon steel or stainless steel and can withstand pressures greater than 0.15 MPa.

[0013] The heat-conducting and pressure-resistant shell of the oxygen supply device is provided with several heat dissipation fins around its periphery.

[0014] Furthermore, the oxygen supply device also includes an explosion-proof unit, which is located at the oxygen outlet of the oxygen supply device and is used to remove sparks generated when the oxygen supply agent produces oxygen.

[0015] Furthermore, the ignition unit is located at the end of the thermally conductive and pressure-resistant housing away from the oxygen outlet. When the ignition device is activated, the oxygen supply agent at the end away from the oxygen outlet begins to initiate the oxygen production reaction.

[0016] The oxygen release rate of the oxygen supply device is adjusted according to the concentration of the combustible waste gas.

[0017] In the oxygen supply device, the oxygen supply agent is cylindrical, stepped shaft-shaped, or conical. The oxygen supply rate and heat exchange area can be adjusted by adjusting the cross-sectional diameter of the stepped shaft-shaped and conical oxygen supply agents.

[0018] Furthermore, the combustible gas includes CO, non-methane CH compounds, H2, and methane.

[0019] Furthermore, based on the total volume of the combustible waste gas to be treated and the content of different gas components in the combustible waste gas, the mass M of the oxygen supply agent in the oxygen supply device satisfies the following condition:

[0020]

[0021] Where M is the effective mass of the oxygen supply agent, in g; η represents the mass percentage of the effective component NaClO3 or KClO3 in the oxygen supply agent; N is the molar volume of the gas; V is the total volume of the combustible waste gas to be treated, in L; x, z, and p correspond to the contents of CO2, non-methane CH compounds, and CH4 in the combustible waste gas to be treated, respectively; the values ​​of x, z, and p are all between 0 and 1; M 供氧剂 The molar mass of NaClO3 / KClO3 is expressed in g / mol.

[0022] Furthermore, the CO catalyst layer uses a copper-manganese catalyst, the non-methane CH compound catalyst layer and the H2 and methane mixed catalyst layer all use noble metal catalysts, and the noble metal catalysts include any one of Pt / Al2O3, Pd / Al2O3, Pt / TiO2, and Pd / TiO2.

[0023] Furthermore, the volume of each catalyst layer is determined according to the following formula:

[0024]

[0025] In the formula, V 催化剂 The volume of the catalyst is expressed in m. 3 Q represents the flue gas volumetric flow rate, in meters. 3 / h;V s This represents airspeed, and is taken as 1000–1000000 h⁻¹ according to actual industrial applications. -1 .

[0026] Furthermore, the catalytic conversion system also includes a heat dissipation reactor, which has the structure of either a heat sink or a corrugated plate and is installed on the side of the outer shell of the catalytic conversion system.

[0027] An application of a catalytic conversion system for high-concentration combustible gases, wherein the catalytic conversion system is used to purify combustible flue gas with an O2 content lower than the O2 content required for catalytic oxidation of waste gas; the combustible flue gas includes low-oxygen combustible gases generated during liquefied petroleum gas leaks, methanol synthesis production, acetylene synthesis production, battery thermal runaway, and coal chemical production processes, wherein the oxygen volume content of the low-oxygen combustible gas is <5%.

[0028] The beneficial effects of this invention are as follows:

[0029] The catalytic conversion system provided by this invention uses the decomposition reaction of oxygen-supplying agents (NaClO3, KClO3) to generate O2 to provide an oxygen source for the catalytic oxidation of combustible gases. It features simple structure, small size, high efficiency in treating waste gas, and low cost.

[0030] This invention provides oxygen through an oxygen-supplying agent, allowing the high-concentration combustible gas to be catalytically converted into non-toxic and harmless H2O and CO2 through its corresponding catalyst. Simultaneously, the heat released during oxygen production and catalytic oxidation by the oxygen-supplying agent gradually increases the temperature of the exhaust gas, thereby enhancing the catalytic performance of the catalyst. The catalytic conversion system provided by this invention does not require an external oxygen source or heat, reducing the cost of exhaust gas treatment and achieving integrated treatment of high-concentration combustible gases. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the catalytic conversion system for combustible waste gas in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of an oxygen supply device.

[0033] Reference numerals in the attached diagram: 1. Flue gas inlet; 2. Oxygen supply device; 3. Catalyst; 4. Catalyst baffle; 5. Flue gas outlet; 6. Outer shell; 2-1. Ignition unit; 2-2. Heat dissipation fins; 2-3. Thermally conductive and pressure-resistant shell; 2-4. Explosion-proof unit; 2-5. Oxygen outlet. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0035] Current technologies for treating high-concentration flammable gases typically employ combustion and catalytic oxidation. However, these methods generally suffer from drawbacks such as complex processes, high costs, and low efficiency. This proposed solution utilizes a coupling technology of an oxygen supply device and a high-performance catalyst. It eliminates the need for additional oxygen sources and heating devices, relying solely on the oxygen and heat released from the reaction itself to treat high-concentration flammable gases. This simplified process reduces treatment costs and expands the scope of application.

[0036] Example 1

[0037] A catalytic conversion system for combustible waste gas based on self-oxygenation, such as... Figure 1 As shown, the catalytic conversion system includes a housing 6; a flue gas inlet 1 and a flue gas outlet 5 are respectively provided at both ends of the housing;

[0038] Along the direction from flue gas inlet 1 to flue gas outlet 5, an oxygen supply device 2 and a catalyst 3 are sequentially arranged inside the shell of the catalytic conversion system. The catalyst sequentially includes a CO catalyst layer, a non-methane CH compound catalyst layer, and a mixed catalyst layer of H2 and methane. A catalyst baffle 4 is arranged between the catalyst 3 and the flue gas outlet 5. The catalyst baffle 4 is used to block and fix the position of the catalyst.

[0039] The oxygen supply device is used to generate oxygen, and the oxygen supply agent used to generate oxygen in the oxygen supply device includes either NaClO3 or KClO3.

[0040] In this embodiment, the catalytic conversion system is used to treat low-oxygen combustible waste gas, where the oxygen volume content is <5%. An oxygen supply agent is used to provide oxygen for the catalytic oxidation reaction. Using an oxygen supply system to provide oxygen for the catalytic oxidation reaction prevents the added oxygen from carrying away heat during flow, thus preventing a decrease in the catalytic temperature and consequently reducing the catalytic performance of the catalyst. The chemical equations for oxygen production from NaClO3 and KClO3 in the oxygen supply agent are shown below:

[0041] 2NaClO3=2NaCl+3O2 (1)

[0042] 2KClO3=2KCl+3O2 (2)

[0043] The arrangement of the CO catalyst layer, the non-methane CH compound catalyst layer, and the H2 and methane mixed catalyst layer is based on the gas composition of the combustible waste gas. Since the catalytic oxidation reaction is an exothermic reaction, the order is based on the optimal catalytic temperature of each combustible gas. According to the data in Table 2, the catalysts are often arranged in the following order: CO catalyst, non-methane CH compound catalyst, H2 catalyst, and methane catalyst.

[0044] like Figure 2 As shown, the oxygen supply device includes a thermally conductive and pressure-resistant housing 2-3, a nutrient solution (including NaClO3 or KClO3) contained in the thermally conductive and pressure-resistant housing, an ignition unit 2-1 disposed at one end of the thermally conductive and pressure-resistant housing, and an oxygen outlet 2-5 disposed at the other end of the thermally conductive and pressure-resistant housing.

[0045] The heat-conducting and pressure-resistant shell of the oxygen supply device is provided with several heat dissipation fins 2-2 around its periphery; the arrangement of the heat dissipation fins gives the oxygen supply device a large heat exchange area, which serves two purposes: first, it can remove the heat generated when the oxygen supply agent is supplying oxygen, thereby reducing the surface temperature of the oxygen supply device; second, it can heat the combustible gas to bring it to the optimal catalytic reaction temperature.

[0046] The ignition unit employs either current-driven or pressure-driven ignition. Current-driven ignition utilizes the thermal effect of current to generate high temperatures for ignition, while pressure-driven ignition generates high temperatures through work. Current-driven ignition is initiated by connecting to an external DC or AC power supply via a wire, and the power switch is controlled by a pressure sensor. The current ignition unit activates when the pressure exceeds a set safety threshold. Pressure-driven ignition, on the other hand, transmits the pressure generated when the safety valve bursts through a lever. The pressure ignition unit activates when the pressure exceeds a set safety threshold.

[0047] Combustible waste gas enters the outer shell of the catalytic conversion system through the flue gas inlet. The combustible waste gas and the heat-conducting, pressure-resistant shell of the oxygen supply device come into full contact, and the combustible waste gas absorbs the heat generated by the oxygen supply device, causing its temperature to rise. Therefore, in this invention, the heat-conducting, pressure-resistant shell of the oxygen supply device is made of a material with good thermal conductivity to facilitate the rapid transfer of heat generated inside the shell to the combustible waste gas. Furthermore, this process rapidly cools the heat-conducting, pressure-resistant shell of the oxygen supply device, preventing excessive internal pressure and the risk of explosion.

[0048] A valve is installed at the flue gas inlet. When the flue gas becomes uncontrolled, a certain pressure is generated. Once the pressure reaches a certain threshold, the safety valve opens. At other times, the valve is closed. When the valve is closed, the thermally conductive and pressure-resistant housing is a sealed thermally conductive and pressure-resistant housing. Specifically, the direction of the oxygen outlet is the same as the flow direction of the combustible waste gas. The released oxygen mixes with the combustible waste gas during the flow process and enters the subsequent gas catalytic layer.

[0049] Specifically, the thermally conductive and pressure-resistant shell is made of metal materials such as carbon steel and stainless steel, and can withstand pressures greater than 0.15 MPa.

[0050] In this embodiment, the oxygen supply device further includes explosion-proof units 2-4. These explosion-proof units are located at the oxygen outlet of the oxygen supply device and are used to remove sparks generated during the oxygen production process of NaClO3 and KClO3. Specifically, the explosion-proof unit is a fire-extinguishing felt installed at the oxygen outlet. The explosion-proof unit is used to remove sparks generated during the oxygen production process of NaClO3 and KClO3, thereby preventing the flammable gas from exploding in the conversion system.

[0051] In this embodiment, specifically, the ignition unit is located at the end of the thermally conductive and pressure-resistant housing that is far from the oxygen outlet. When the ignition device is started, the NaClO3 or KClO3 at the end far from the oxygen outlet begins to initiate the oxygen production reaction.

[0052] The oxygen release rate of the oxygen supply device is adjusted according to the concentration of the combustible waste gas.

[0053] In oxygen supply devices, the oxygen supply agent is cylindrical, stepped shaft-shaped, or conical. The stepped shaft-shaped and conical oxygen supply agents can adjust the oxygen supply rate and increase the heat exchange area. For example, a solid cylindrical oxygen supply agent (active ingredient NaClO3) with a diameter of 80mm and a height of 100mm has an actual oxygen release capacity of approximately 200L.

[0054] The oxygen release rate of the oxygen supply device is positively correlated with the cross-sectional diameter of the oxygen supply agent. Therefore, the oxygen release rate of the oxygen supply device can be adjusted by changing the cross-sectional diameter of the oxygen supply agent.

[0055] Preferably, the oxygen supply agent in the oxygen supply device is conical, and the cross-sectional diameter of the oxygen supply agent decreases from the end of the thermally conductive and pressure-resistant housing away from the oxygen outlet to the end of the oxygen outlet; after the ignition unit is started, the oxygen release rate of the oxygen supply device changes from fast to slow, and the heat generated also changes from more to less.

[0056] In this embodiment, the combustible gas includes CO, non-methane CH compounds, H2, and methane.

[0057] In this embodiment, the mass of the oxygen supply agent is determined based on the total volume of the combustible waste gas to be treated and the content of different gas components in the waste gas, which must satisfy the following relationship:

[0058] Table 1. Flue gas composition and total volume in high-concentration combustible gases (x, y, and z are all between 0 and 1)

[0059]

[0060] The total volume of O2 required for the catalytic oxidation of CO, CH4, and H2 can be calculated using the following formula.

[0061]

[0062] Based on the total volume of the combustible waste gas to be treated and the content of different gas components in the combustible waste gas, the mass M of the oxygen supply agent in the oxygen supply device satisfies the following conditions:

[0063]

[0064] Where M is the effective mass of the oxygen-supplying agent, in g; η represents the mass percentage of the effective component NaClO3 or KClO3 in the oxygen-supplying agent, η being within the range of 20% to 80%; N is the molar volume of the gas, taken as 22.4 L / mol under standard conditions; V is the total volume of the combustible waste gas to be treated, in L; n and m represent the non-methane hydrocarbon C n H m In this context, n and m; x, y, z, and p correspond to the contents of CO2, CO, non-methane CH compounds, and CH4 in the combustible waste gas to be treated, respectively; the H2 content is 1-xyzp; the values ​​of x, y, z, and p are all between 0 and 1; M 供氧剂 The molar mass of NaClO3 / KClO3 is expressed in g / mol. If NaClO3 is chosen as the oxygen supply agent, M... 供氧剂 It is 106.44 g / mol.

[0065] In this embodiment, the CO catalyst layer uses a copper-manganese catalyst, the non-methane CH compound catalyst layer and the H2 and methane mixed catalyst layer all use noble metal catalysts. These noble metal catalysts include any one of Pt / Al2O3, Pd / Al2O3, Pt / TiO2, and Pd / TiO2. Due to the high reaction temperature, the C-based support may be at risk of ignition; therefore, the use of C-based support catalysts should be avoided as much as possible. For example, if the gas composition of a flue gas is CO2 (32.5 vol%), CO (12.7 vol%), C2H4 (5.3 vol%), H2 (48 vol%), and CH4 (1.3 vol%), and the total volume of the flue gas is 263.8 L, and the effective NaClO3 content in the oxygen supply agent is 60%, based on calculations and actual working conditions, the above flue gas requires at least 681.77 g of oxygen supply agent as an oxygen source.

[0066] In this embodiment, the volume of each catalyst layer is determined according to the following formula:

[0067]

[0068] In the formula, V 催化剂 The volume of the catalyst is expressed in m. 3 Q represents the flue gas volumetric flow rate, in meters. 3 / h;V s This represents airspeed, and is taken as 1000–1000000 h⁻¹ according to actual industrial applications. -1 .

[0069] In this embodiment, the catalytic conversion system further includes a heat dissipation reactor, which has the structure of either a heat sink or a corrugated plate, and is installed on the side of the outer casing of the catalytic conversion system. Specifically, heat dissipation reactors are installed on three outer sides of the outer casing of the catalytic conversion system, and external components such as batteries are installed on one side.

[0070] Preferably, to save space and control gas flow, the oxygen supply system and each catalyst layer are tightly fitted together; the gap between adjacent layers is no more than 5 mm.

[0071] The optimal catalytic temperatures for combustible gases CO, non-methane CH compounds, H2, and methane are shown in Table 2.

[0072] Table 2 Optimal catalytic oxidation temperatures for different combustible gases

[0073]

[0074] As can be seen, in this invention, the arrangement of different combustible gas catalyst layers along the flue gas flow direction is as follows: the combustible gas catalyst layers are arranged from low to high according to the optimal activation catalytic temperature of the corresponding catalyst for each different combustible gas; the arrangement of the above-mentioned different combustible gas catalyst layers can increase the flue gas temperature by means of the heat released by the catalytic oxidation reaction, thereby enabling the next type of combustible gas to reach its optimal catalytic oxidation temperature.

[0075] For example, if the gaseous components of a certain waste gas are CO2 (16.8 vol%), CO (18.5 vol%), CH3OH (33.9 vol%), and H2 (30.6 vol%), and the total volume of the flue gas is 35829.7 L, according to calculations and actual working conditions, the above flue gas requires at least 174889.78 g of oxygen supply agent (the effective NaClO3 content in the oxygen supply agent is 60%, but in this example, to increase a certain margin and save costs, 175000 g of oxygen supply agent is used) as an oxygen source, and a corresponding catalyst is set up to use the O2 generated by the oxygen supply agent to catalytically oxidize the combustible gas.

[0076] Example 2

[0077] The application of a catalytic conversion device for combustible waste gas involves using the catalytic conversion device described in Example 1 for the purification of combustible waste gas with no or low oxygen content (<5 vol%). This includes combustible gases generated during liquefied petroleum gas leaks, methanol synthesis production, acetylene synthesis production, battery thermal runaway, and coal chemical production processes. The catalytic conversion device for combustible waste gas provided by this invention can reduce the risk of explosion.

[0078] Example 3

[0079] Table 3 shows the composition of a certain gas. As can be seen from Table 3, the composition of the flue gas is simple, but the total volume and flow rate of the flue gas are very large.

[0080] Table 3. Composition and removal rate of flue gas generated after a period of time from a methanol synthesis plant leak.

[0081]

[0082] The gas was treated using the catalytic conversion equipment described in Example 2, wherein the catalyst was coated on a honeycomb carrier, and each catalyst layer had a volume of 300 cm³. 3 The amount of oxygen-supplying agent (with 60% effective NaClO3 content) was 175,000 g. The removal rate of all combustible gases reached over 95%, indicating that the catalytic conversion equipment provided by this invention has excellent flue gas treatment performance.

[0083] Example 4

[0084] Table 4 shows the composition of a certain gas. As can be seen from Table 4, the composition of the flue gas is simple, but the total volume and flow rate of the flue gas are very large.

[0085] Table 4. Composition and Removal Rate of Flue Gas Generated After a Period of Time Following a CO Storage Tank Leak at a Coal Chemical Plant

[0086]

[0087]

[0088] The gas was treated using the catalytic conversion equipment described in Example 2, wherein the catalyst was coated on a honeycomb carrier, and each catalyst layer had a volume of 600 cm³. 3 The amount of oxygen-supplying agent (with 60% effective NaClO3 content) was 143,900 g. The removal rate of all combustible gases reached over 95%, indicating that the catalytic conversion equipment provided by this invention has excellent flue gas treatment performance.

[0089] Example 5

[0090] Table 5 shows the gas composition of a certain battery during thermal runaway. As can be seen from Table 5, the flue gas contains a large proportion of combustible gases and has a high flow rate.

[0091] Table 5. Composition and removal rate of flue gas generated after thermal runaway of a single lithium battery.

[0092]

[0093] The gas was treated using the catalytic conversion equipment described in Example 2, wherein the catalyst was spherical and the volume of each catalyst layer was 5 cm³. 3 The amount of oxygen supply agent (with 60% effective NaClO3 content) used is 700g. The removal rate of all combustible gases reaches over 95%, indicating that the catalytic conversion equipment provided by this invention has excellent flue gas treatment effect.

[0094] Example 6

[0095] Table 6 shows the composition of a certain gas. As can be seen from Table 6, the flue gas has a simple composition and a large total volume and flow rate.

[0096] Table 6. Composition and Removal Rate of Flue Gas Generated After a Period of Leakage in a Liquefied Petroleum Gas Production Pipeline

[0097]

[0098] The gas was treated using the catalytic conversion equipment described in Example 2, wherein the catalyst was coated on a honeycomb carrier, and each catalyst layer had a volume of 50 cm³. 3The amount of oxygen-supplying agent (with 60% effective NaClO3 content) was 8100g. The removal rate of all combustible gases reached over 95%, indicating that the catalytic conversion equipment provided by this invention has excellent flue gas treatment performance.

[0099] Example 7

[0100] Table 7 shows the composition of a certain gas. As can be seen from Table 7, the flue gas has a complex composition and a large total volume and flow rate.

[0101] Table 7. Composition and Removal Rate of Flue Gas Generated After a Period of Leakage in a Coal-to-Ammonia Synthesis Production Pipeline

[0102]

[0103] The gas was treated using the catalytic conversion equipment described in Example 2, wherein the catalyst was coated on a honeycomb carrier, and each catalyst layer had a volume of 80 cm³. 3 The amount of oxygen-supplying agent (with 50% effective KClO3 content) was 26,900 g. The removal rate of all combustible gases reached over 95%, indicating that the catalytic conversion equipment provided by this invention has excellent flue gas treatment performance.

[0104] Comparative Example 1

[0105] The combustible flue gas removal rate of the gas in Example 3 was treated using an external O2 (without oxygen supply agent) method, as shown in Table 8. Compared with Example 3, although the external O2 method saves costs to some extent (due to the lack of oxygen supply agent), the external O2 carries away a large amount of heat when flowing through the flue gas, reducing the catalytic performance of the catalyst and thus reducing the combustible flue gas removal rate.

[0106] Table 8. Composition and Removal Rate of Flue Gas Generated from a Methanol Synthesis Plant After a Period of Leakage.

[0107]

[0108] Comparative Example 2

[0109] The gas in Example 3 was treated using ethylene glycol, organic ethers, and ionic liquid treatment agents. The removal rates of combustible flue gas are shown in Table 9. Compared to Example 3, this method has a relatively good removal rate of organic waste gas, but its removal rates of CO and H2 are lower. Furthermore, it also suffers from drawbacks such as high treatment costs and difficulty in recycling the treatment agents.

[0110] Table 9. Composition and Removal Rate of Flue Gas Generated from a Methanol Synthesis Plant After a Period of Leakage.

[0111]

[0112] The catalytic conversion system provided by this invention mainly consists of an oxygen supply device and a catalyst component. The oxygen supply device comprises an oxygen supply agent (mainly composed of NaClO3 and KClO3), an ignition unit, and an explosion-proof unit. The oxygen supply device is placed before the catalyst to provide the necessary oxygen for the subsequent catalytic oxidation reaction of combustible gases. Low-oxygen, high-concentration combustible gases are gradually catalytically oxidized into non-toxic and harmless CO2 and H2O through this system. This system has advantages such as high catalytic efficiency, compact structure, small footprint, and low production and maintenance costs; it solves the problems of high cost, low efficiency, and large footprint in the treatment of leaked flue gas in existing chemical production processes. The catalytic conversion system provided by this invention is an integrated combustible gas treatment equipment. Depending on actual needs, it can be a disposable product or a recyclable product. When it is a recyclable product, the oxygen supply agent in the unit needs to be replaced after each use, and its outer shell needs to be thickened.

[0113] Comparative Example 3

[0114] The gas in Example 3 was treated using physical adsorption methods such as molecular sieves and activated carbon. The removal rate of combustible flue gas is shown in Table 10. Compared with Example 3, this method can absorb most of CH3OH (removal rate of 92.1%), but its removal rates of CO and H2 are lower, especially the removal rate of H2, which is only 39.5%.

[0115] Table 10. Composition and Removal Rate of Flue Gas Generated from a Methanol Synthesis Plant After a Period of Leakage.

[0116]

[0117] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, modifications or variations can still be made to the technical solutions described above, and these modifications and variations all fall within the protection scope of the present invention.

Claims

1. A catalytic conversion system for combustible waste gas based on self-oxygenation, characterized in that, The catalytic conversion system includes a shell; a flue gas inlet and a flue gas outlet are respectively provided at both ends of the shell; Along the direction from flue gas inlet to flue gas outlet, an oxygen supply device, a CO catalyst layer, a non-methane CH compound catalyst layer, and a mixed catalyst layer of H2 and methane are sequentially arranged inside the shell of the catalytic conversion system. The oxygen supply device is used to generate oxygen, and the oxygen supply agent used to generate oxygen in the oxygen supply device includes either NaClO3 or KClO3.

2. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 1, characterized in that, The oxygen supply device includes a thermally conductive and pressure-resistant housing, an oxygen supply agent contained in the thermally conductive and pressure-resistant housing, an ignition unit disposed at one end of the thermally conductive and pressure-resistant housing, and an oxygen outlet disposed at the other end of the thermally conductive and pressure-resistant housing. The thermally conductive and pressure-resistant housing is made of carbon steel or stainless steel and can withstand pressures greater than 0.15 MPa. The heat-conducting and pressure-resistant shell of the oxygen supply device is provided with several heat dissipation fins around its periphery.

3. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 2, characterized in that, The oxygen supply device also includes an explosion-proof unit, which is located at the oxygen outlet of the oxygen supply device and is used to remove sparks generated when the oxygen supply agent produces oxygen.

4. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 2, characterized in that, The ignition unit is located at the end of the thermally conductive and pressure-resistant housing that is far from the oxygen outlet. When the ignition device is started, the oxygen supply agent at the end far from the oxygen outlet begins to initiate the oxygen production reaction. The oxygen release rate of the oxygen supply device is adjusted according to the concentration of the combustible waste gas. In oxygen supply devices, the oxygen supply agent is in the form of a cylinder, a stepped shaft, or a cone.

5. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 1, characterized in that, The combustible gas includes CO, non-methane CH compounds, H2, and methane.

6. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 5, characterized in that, Based on the total volume of the combustible waste gas to be treated and the content of different gas components in the combustible waste gas, the mass M of the oxygen supply agent in the oxygen supply device satisfies the following conditions: Where M is the effective mass of the oxygen supply agent, in g; η represents the mass percentage of the effective component NaClO3 or KClO3 in the oxygen supply agent; N is the molar volume of the gas; V is the total volume of the combustible waste gas to be treated, in L; x, z, and p correspond to the contents of CO2, non-methane CH compounds, and CH4 in the combustible waste gas to be treated, respectively; the values ​​of x, z, and p are all between 0 and 1; M 供氧剂 The molar mass of NaClO3 / KClO3 is expressed in g / mol.

7. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 1, characterized in that, The CO catalyst layer uses a copper-manganese catalyst, the non-methane CH compound catalyst layer and the H2 and methane mixed catalyst layer all use noble metal catalysts, and the noble metal catalysts include any one of Pt / Al2O3, Pd / Al2O3, Pt / TiO2 and Pd / TiO2.

8. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 1, characterized in that, The volume of each catalyst layer is determined according to the following formula: In the formula, V 催化剂 The volume of the catalyst is expressed in m. 3 Q represents the flue gas volumetric flow rate, in meters. 3 / h;V s This represents airspeed, and is taken as 1000–1000000 h⁻¹ according to actual industrial applications. -1 .

9. The catalytic conversion system for combustible waste gas based on self-oxygenation according to claim 1, characterized in that, The catalytic conversion system also includes a heat dissipation reactor, which has the structure of either a heat sink or a corrugated plate and is installed on the side of the outer shell of the catalytic conversion system.

10. The application of the catalytic conversion system for high-concentration combustible gas as described in claims 1-9, characterized in that, The catalytic conversion system is used to purify combustible flue gas with an O2 content lower than that required for catalytic oxidation of waste gas; the combustible flue gas includes low-oxygen combustible gases generated during liquefied petroleum gas leaks, methanol synthesis production, acetylene synthesis production, battery thermal runaway, and coal chemical production processes, wherein the oxygen volume content of the low-oxygen combustible gas is <5%.

Images