Device for evaluating catalytic performance of formaldehyde oxidation catalyst

Abstract

The utility model belongs to the technical field of formaldehyde catalytic oxidation treatment, and discloses a device for evaluating the catalytic performance of a formaldehyde oxidation catalyst, which comprises a gas supply unit, a gas generation unit and a formaldehyde reaction unit, the gas generation unit comprises a water vapor generation module and a formaldehyde gas generation module; the steam generation module comprises a first water bath kettle and a steam generation pipe; the water vapor generating pipe is sealed and tubular, the lower end of the water vapor generating pipe is immersed in the first water bath kettle, distilled water is filled in the water vapor generating pipe, the upper end of the water vapor generating pipe is communicated with a first inlet guide pipe, and the lower end of the first inlet guide pipe is immersed below the distilled water level in the water vapor generating pipe; according to the device, the formaldehyde concentration is accurately regulated and controlled, so that formaldehyde mixed gas with stable components is obtained at low cost, the wet and dry formaldehyde catalytic oxidation performance of the catalyst can be efficiently and conveniently evaluated, and the development efficiency of the catalyst is favorably improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of formaldehyde catalytic oxidation treatment, and particularly relates to a device for evaluating the catalytic performance of a formaldehyde oxidation catalyst. Background Technique

[0002] The industrial production process is one of the main sources of formaldehyde waste gas, such as the chemical industry, printing, painting and other industries. If these formaldehyde waste gases are directly discharged into the atmosphere without treatment, they will seriously damage people's nerves, and staying in such an environment for a long time may cause cancer. With the increasing attention of the country to environmental protection, the emission standards for organic waste gas treatment are getting higher and higher. The formaldehyde catalytic oxidation technology is a common formaldehyde purification technology, which uses a catalyst to quickly decompose formaldehyde into harmless carbon dioxide and water, avoiding the problem of secondary pollution. Due to its high efficiency, no secondary pollution, wide application and other characteristics, the formaldehyde catalytic oxidation technology is widely used in improving indoor air quality and treating formaldehyde pollution in industrial emissions.

[0003] In the R & D process of formaldehyde catalysts, it is necessary to finely adjust the components and process parameters of the catalysts according to the catalytic performance, so as to prepare high-performance and low-cost formaldehyde catalysts. The R & D process of formaldehyde catalysts involves frequent catalytic performance evaluation experiments. Therefore, the development of a device for evaluating the catalytic performance of formaldehyde oxidation catalysts is of great significance to the development of formaldehyde waste gas purification technology. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a device for evaluating the catalytic performance of a formaldehyde oxidation catalyst, which can conveniently, quickly and accurately evaluate the catalytic performance of the formaldehyde catalyst and facilitate the promotion of the R & D of the formaldehyde catalyst.

[0005] The purpose of the utility model can be realized by the following technical solutions:

[0006] A device for evaluating the catalytic performance of a formaldehyde oxidation catalyst includes a gas supply unit, a gas generation unit and a formaldehyde reaction unit;

[0007] The gas generation unit includes a water vapor generation module and a formaldehyde gas generation module;

[0008] The water vapor generation module includes a first water bath and a water vapor generation tube; the water vapor generation tube is a sealed tube and its lower end is immersed in the first water bath. Distilled water is contained in the water vapor generation tube. The upper end of the water vapor generation tube is connected through a first inlet conduit, and the lower end of the first inlet conduit is immersed below the liquid level of the distilled water in the water vapor generation tube. A first outlet conduit and a pressure sensor are also arranged at the top of the water vapor generation tube;

[0009] The formaldehyde gas generation module includes a second water bath and a formaldehyde generation tube; the formaldehyde generation tube is a sealed tube, and its lower end is immersed in the second water bath. A paraformaldehyde powder bed is provided at the inner bottom of the formaldehyde generation tube. The formaldehyde generation tube is provided with a second inlet conduit that penetrates from the top and enters. The lower end of the second inlet conduit is a conical opening and extends into the paraformaldehyde powder bed. A second outlet conduit for leading out formaldehyde gas is also provided at the top of the formaldehyde generation tube;

[0010] The gas supply unit includes an oxygen cylinder, a nitrogen cylinder, a three-way valve and a four-way valve. The oxygen cylinder is connected to one end of the four-way valve through a first pipe. An oxygen master valve and a first flow meter are provided on the first pipe. The nitrogen cylinder is connected to one end of the three-way valve through a second pipe. A nitrogen master valve is provided on the second pipe. The other two ends of the three-way valve are respectively provided with a third pipe and a fourth pipe. A second flow meter is provided on the third pipe. The other end of the third pipe is connected to the first inlet conduit. A third flow meter is provided on the fourth pipe. The other end of the third pipe is connected to the second inlet conduit. The other three ends of the four-way valve are respectively connected to a fourth pipe, a fifth pipe and a sixth pipe. The other end of the fourth pipe is connected to the upper end of the first outlet conduit. A supply valve is provided on the fourth pipe. The other end of the fifth pipe is connected to the upper end of the second outlet conduit. The sixth pipe is connected to the formaldehyde reaction unit;

[0011] The formaldehyde reaction unit includes a first reaction three-way reversing valve, a tubular heating furnace, and a reaction tube; the tubular heating furnace has a cylindrical cavity inside, and a heating wire and a fourth temperature sensor are provided in the cavity. The reaction tube includes a reaction inlet tube and a reaction outlet tube. The reaction inlet tube and the reaction outlet tube form a U-shaped reaction tube. The lower half of the reaction tube is located in the cavity of the tubular heating furnace. The U-shaped bottom of the reaction tube is a reduced diameter. A quartz wool bed is provided at the side bottom of the reaction inlet tube. A catalytic material bed is provided on the quartz wool bed. A sleeve is provided in the reaction inlet tube. A third temperature sensor is provided inside the sleeve. The lower ends of the sleeve and the third temperature sensor are both located inside the catalytic material bed. The first reaction three-way reversing valve is connected to the upper end of the reaction inlet tube through a tenth pipe. The other end of the first reaction three-way reversing valve is connected to the sixth pipe through connection;

[0012] The formaldehyde reaction unit is connected to a chromatographic detection unit for detecting the components of the tail gas after catalytic combustion. An exhaust unit for exhausting waste gas is connected to the chromatographic unit;

[0013] The chromatographic detection unit includes a chromatograph, which is provided with an air inlet end and an air outlet end. The air inlet end is connected to the reaction outlet pipe through a seventh pipe. The seventh pipe is divided into two disconnected sections, and the two sections of the seventh pipe are connected through a third reaction three-way reversing valve. One end of the first reaction three-way reversing valve away from the sixth pipe and the reaction inlet pipe is connected to an eighth pipe. The upper end of the eighth pipe is connected to a second reaction three-way reversing valve. The second reaction three-way reversing valve is connected to the end of the third reaction three-way reversing valve away from the seventh pipe through a ninth pipe. The air outlet end is connected to an exhaust three-way pipe, and the other two ends of the exhaust three-way pipe are respectively connected to the second reaction three-way reversing valve and the evacuation unit;

[0014] The exhaust unit includes a soap film flow tube, which is provided with an evacuation port and a soap solution balloon at its upper and lower parts respectively. The soap solution balloon is filled with saponifying solution. The tube wall of the soap film flow tube is provided with volume scales, and the side wall of the lower part of the soap film flow tube is provided with a soap film flow tube air inlet. One end of the exhaust three-way pipe connected to the evacuation unit is connected to the soap film flow tube air inlet;

[0015] A first pipeline heating tape is wound around the fourth pipe connected to the first outlet conduit, a second pipeline heating tape is wound around the fifth pipe connected to the second outlet conduit, a third pipeline heating tape is wound around the sixth pipe between the four-way valve and the formaldehyde reaction unit, and a fourth pipeline heating tape is wound around the seventh pipe connected to the reaction outlet pipe. A first temperature sensor and a second temperature sensor are respectively arranged on the third pipeline heating tape and the fourth pipeline heating tape.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. In this application, the formaldehyde generation module uses a water bath method to achieve stable temperature control of the paraformaldehyde powder bed layer. Nitrogen is introduced into the paraformaldehyde powder bed layer through the conical outlet structure of the second inlet conduit, realizing the supply of formaldehyde gas with a stable concentration. The water vapor generation module uses a water bath and nitrogen bubbling method to obtain water vapor supply, and then realizes the catalytic performance evaluation of the device in two modes: dry formaldehyde and wet formaldehyde. This application can accurately regulate the formaldehyde concentration, and then obtain a formaldehyde mixed gas with stable components at low cost, and can efficiently and conveniently evaluate the wet and dry formaldehyde catalytic oxidation performance of the catalyst, which is beneficial to improving the development efficiency of the catalyst;

[0018] 2. The single - time paraformaldehyde powder filling of this device can meet the experimental requirements of at least 4 months of formaldehyde gas with a concentration of 150 ppm, and has the advantages of low cost and stable reaction gas supply;

[0019] 3. In this application, a first pipeline heating tape, a second pipeline heating tape, a third pipeline heating tape and a fourth pipeline heating tape are arranged on the pipelines of the generated water vapor, formaldehyde gas and mixed gas, avoiding the condensation problem of the generated gas and ensuring the stability of each component of the mixed gas. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0021] Figure 1 is a schematic diagram of the overall structure of the present disclosure;

[0022] Figure 2 is a schematic diagram of the structures of the water vapor generation unit and the formaldehyde generation unit of the present disclosure;

[0023] Figure 3 is a schematic diagram of the structure of the formaldehyde reaction unit of the present disclosure;

[0024] Figure 4 is a schematic diagram of the quick-connection sealing structure of the present disclosure;

[0025] Figure 5 is a schematic diagram of the structures of the chromatographic detection unit and the evacuation unit of the present disclosure;

[0026] Figure 6 is a schematic diagram of the performance evaluation mode of the dry formaldehyde catalytic material of the present disclosure;

[0027] Figure 7 is an evaluation curve graph of the temperature-conversion rate of the catalyst.

[0028] Reference numerals:

[0029] 1. Gas supply unit; 11. Oxygen cylinder; 111. Oxygen main valve; 112. First mass flowmeter; 12. Nitrogen cylinder; 121. Nitrogen main valve; 122. Three-way valve; 13. Four-way valve; 2. Gas generation unit; 21. Steam generation module; 211. First water bath; 212. Steam generation pipe; 213. Distilled water; 214. First inlet conduit; 215. First outlet conduit; P. Pressure sensor; 2151. First pipeline heating tape; 216. Second flowmeter; 217. Supply valve; 22. Formaldehyde gas generation module; 221. Second water bath; 222. Formaldehyde gas generation pipe; 223. Paraformaldehyde powder bed; 224. Second inlet conduit; 2241. Conical orifice; 225. Second outlet conduit; 2251. Second pipeline heating tape; 226. Third flowmeter; 3. Formaldehyde reaction unit; 31. Third pipeline heating tape; 32. First reaction three-way reversing valve; T1. First temperature sensor; T2. Second temperature sensor; T3. Third temperature sensor; 33. Tube furnace; T4. Fourth temperature sensor; 34. Heating wire; 35. Reaction tube; 36. Fourth pipeline heating tape; 351. Quartz wool bed; 352. Catalytic material bed; 353. Sleeve; 354. Reaction outlet pipe; 355. Reaction inlet pipe; 3551. O-ring; 3552. Lower seal nut ferrule; 3553. Compression thread; 3554. Upper seal nut ferrule; 35541. Channel; 35542. Inlet of upper seal nut ferrule; 4. Chromatographic detection unit; 41. Second reaction three-way reversing valve; 42. Third reaction three-way reversing valve; 43. Inlet end; 44. Chromatograph; 45. Outlet end; 46. Exhaust three-way pipe; 5. Evacuation unit; 51. Evacuation port; 52. Soap film flow tube; 53. Soap solution balloon; 531. Saponified solution; 54. Inlet of soap film flow tube. Detailed implementation manners

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figures 1 to 7 shown, a device for evaluating the catalytic performance of a formaldehyde oxidation catalyst includes a gas supply unit 1, a gas generation unit 2, and a formaldehyde reaction unit 3;

[0032] The gas generation unit 2 includes a steam generation module 21 and a formaldehyde gas generation module 22;

[0033] The water vapor generation module 21 includes a first water bath 211 and a water vapor generation pipe 212; the water vapor generation pipe 212 is a sealed tube and its lower end is immersed in the first water bath 211. Distilled water 213 is contained in the water vapor generation pipe 212. The upper end of the water vapor generation pipe 212 is connected through a first inlet conduit 214. The lower end of the first inlet conduit 214 is immersed below the liquid level of the distilled water 213 in the water vapor generation pipe 212. A first outlet conduit 215 and a pressure sensor P are also provided at the top of the water vapor generation pipe 212;

[0034] The formaldehyde gas generation module 22 includes a second water bath 221 and a formaldehyde generation pipe 222; the formaldehyde generation pipe 222 is a sealed tube and its lower end is immersed in the second water bath 221. A paraformaldehyde powder bed 223 is provided at the inner bottom of the formaldehyde generation pipe 222. The formaldehyde generation pipe 222 is provided with a second inlet conduit 224 that penetrates from the top. The lower end of the second inlet conduit 224 is a conical port 2241 and extends into the paraformaldehyde powder bed 223. A second outlet conduit 225 for leading out formaldehyde gas is also provided at the top of the formaldehyde generation pipe 222;

[0035] The gas supply unit 1 includes an oxygen cylinder 11, a nitrogen cylinder 12, a three-way valve 122 and a four-way valve 13. The oxygen cylinder 11 is connected to one end of the four-way valve 13 through a first pipe. An oxygen main valve 111 and a first flow meter 112 are provided on the first pipe. The nitrogen cylinder 12 is connected to one end of the three-way valve 122 through a second pipe. A nitrogen main valve 121 is provided on the second pipe. The other two ends of the three-way valve 122 are respectively provided with a third pipe and a fourth pipe. A second flow meter 216 is provided on the third pipe. The other end of the third pipe is connected to the first inlet conduit 214. A third flow meter 226 is provided on the fourth pipe. The other end of the third pipe is connected to the second inlet conduit 224. The other three ends of the four-way valve 13 are respectively connected to a fourth pipe, a fifth pipe and a sixth pipe. The other end of the fourth pipe is connected to the upper end of the first outlet conduit 215. A supply valve 217 is provided on the fourth pipe. The other end of the fifth pipe is connected to the upper end of the second outlet conduit 225. The sixth pipe is connected to the formaldehyde reaction unit 3;

[0036] The formaldehyde reaction unit 3 includes a first reaction three-way reversing valve 32, a tubular heating furnace 33, and a reaction tube 35; the tubular heating furnace 33 has a cylindrical cavity inside, and a heating wire 34 and a fourth temperature sensor T4 are arranged in the cavity. The reaction tube 35 includes a reaction inlet tube 355 and a reaction outlet tube 354. The reaction inlet tube 355 and the reaction outlet tube 354 form a U-shaped reaction tube 35. The lower half of the reaction tube 35 is located in the cavity of the tubular heating furnace 33. The U-shaped bottom of the reaction tube 35 is reduced in diameter. A quartz wool bed layer 351 is arranged at the bottom side of the reaction inlet tube 355, and a catalytic material bed layer 352 is arranged on the quartz wool bed layer 351. A sleeve 353 is arranged in the reaction inlet tube 355, and a third temperature sensor T3 is arranged inside the sleeve 353. The lower ends of the sleeve 353 and the third temperature sensor T3 are both located inside the catalytic material bed layer 352. The first reaction three-way reversing valve 32 is connected to the upper end of the reaction inlet tube 355 through a tenth tube, and the other end of the first reaction three-way reversing valve 32 is connected through a sixth tube;

[0037] The formaldehyde reaction unit 3 is connected to a chromatographic detection unit 4, and the chromatographic detection unit 4 is used to detect the components of the tail gas after catalytic combustion. An exhaust unit 5 for exhausting waste gas is connected to the chromatographic unit;

[0038] By setting the supply valve 217, the switching between the dry or wet formaldehyde catalytic performance evaluation modes is realized;

[0039] Oxygen, water vapor, and formaldehyde gas converge at the four-way valve 13 to form a formaldehyde mixed gas (components: formaldehyde, oxygen, nitrogen, water vapor), which provides the formaldehyde mixed gas for the formaldehyde reaction unit 3;

[0040] The chromatographic detection unit 4 includes a chromatograph 44. The chromatograph 44 is provided with an air inlet end 43 and an air outlet end 45. The air inlet end 43 is connected to the reaction outlet tube 354 through a seventh tube. The seventh tube is in two disconnected sections, and the two sections of the seventh tube are connected through a third reaction three-way reversing valve 42. One end of the first reaction three-way reversing valve 32 away from the sixth tube and the reaction inlet tube 355 is connected to an eighth tube. The upper end of the eighth tube is connected to a second reaction three-way reversing valve 41. The second reaction three-way reversing valve 41 is connected to the end of the third reaction three-way reversing valve 42 away from the seventh tube through a ninth tube. The air outlet end 45 is connected to an exhaust three-way pipe 46. The other two ends of the exhaust three-way pipe 46 are respectively connected to the second reaction three-way reversing valve 41 and the exhaust unit 5. Through the combined operation of the second reaction three-way reversing valve 41 and the third reaction three-way reversing valve 42, the control of gas path control modes such as initial mixed gas component detection (without passing through the formaldehyde reaction unit 33), normal detection (passing through the formaldehyde reaction unit 3 and the chromatographic detection unit 4), and end direct exhaust (without passing through the chromatographic detection unit 4) is realized.

[0041] The exhaust unit includes a soap film flow tube 52, with an air vent 51 and a soap solution balloon 53 provided at its upper and lower parts respectively. The soap solution balloon 53 is filled with a saponification solution 531. The tube wall of the soap film flow tube 52 is provided with volume scales, and a soap film flow tube air inlet 54 is provided on the lower side wall of the soap film flow tube 52. One end of the exhaust tee 46 connecting the evacuation unit 5 is connected to the soap film flow tube air inlet 54;

[0042] The soap film flow tube 52 can generate soap solution bubbles by squeezing the soap solution balloon 53. By combining a stopwatch to detect the time for the bubbles to pass through two volume scales of the soap film flow tube 52, the flow rate of the pipeline can be calculated, which is convenient for regularly calibrating the flow rate of the device.

[0043] A first pipeline heating tape 2151 is wound around the fourth tube connected to the first outlet conduit 215, a second pipeline heating tape 2251 is wound around the fifth tube connected to the second outlet hole conduit, a third pipeline heating tape 31 is wound around the sixth tube between the four-way valve 13 and the formaldehyde reaction unit 3, and a fourth pipeline heating tape 36 is wound around the seventh tube connected to the reaction outlet pipe 354. A first temperature sensor T1 and a second temperature sensor T2 are respectively provided on the third pipeline heating tape 31 and the fourth pipeline heating tape 36; this avoids the problem of abnormal components caused by the condensation of the generated gas and formaldehyde mixture; and the first temperature sensor T1 and the second temperature sensor T2 are set to monitor the temperature in real time to ensure that the temperature of the heating tape is between 110 - 130 °C.

[0044] Preferably, a quick-connect sealing structure is provided on the reaction inlet pipe 355. The quick-connect sealing structure is sleeved on the reaction inlet pipe 355. The quick-connect sealing structure includes a lower sealing nut sleeve 3552, an O-ring 3551, and an upper sealing nut sleeve 3554, which are sequentially sleeved outside the reaction pipe 35. A compression thread 3553 is provided on the outer side wall of the reaction inlet pipe 355. The lower sealing nut sleeve 3552 and the upper sealing nut sleeve 3554 achieve axial movement through threaded connection to compress the O-ring 3551. A channel 35541 for the third temperature sensor T3 to pass through is provided on the upper sealing nut sleeve 3554, and an upper sealing nut sleeve air inlet 35542 is provided at the upper end of the upper sealing nut sleeve 3554. The tenth tube is connected to the upper sealing nut sleeve 3554, so as to improve the connection stability and sealing performance between the reaction inlet pipe 355 and the tenth tube, and at the same time facilitate the replacement of the reaction pipe 35 and the test sample.

[0045] Next, the technical solution of the present utility model will be further elaborated in combination with specific embodiments:

[0046] Taking three formaldehyde catalyst samples of 1Pd / MgFe2O4-500℃, 1Pd / MgFe2O4-700℃, and 1Pd / MgFe2O4-850℃ (spinel ferrite-supported palladium metal catalysts) as examples, the influence of the catalyst calcination temperature from 500℃ to 850℃ on the catalytic activity of formaldehyde was evaluated. The specific evaluation steps are as follows:

[0047] (1) Loading the catalyst: Fill 1 cm high quartz wool in the reaction tube 35 and compact it with a glass rod to form a quartz wool bed layer 351. Take 50 mg of the catalyst and mix it evenly with 1000 mg of quartz sand, then pour it into the reaction tube 35 to form a catalytic material bed layer 352; Insert the sleeve 353 into the catalytic material bed layer 352, guide and insert the third temperature sensor T3 into the quartz sleeve 353 of the third temperature sensor T3, ensuring that the end of the third temperature sensor T3 is located within the catalytic material bed layer 352. Lock the lower sealing nut ferrule 3552 to fix both ends of the reaction tube 35 on the device, completing the work of loading the catalyst.

[0048] (2) Preparing the formaldehyde mixed gas: Control the three-way reaction valve 122 reversing valve to directly introduce the mixed gas into the chromatograph 44 (without passing through the reaction tube 35); Set both the first temperature sensor T1 and the second temperature sensor T2 to 120℃; Set the nitrogen flow rate to 12.5 ml / min through the second flowmeter 216 and introduce nitrogen into the steam generation tube 212 to achieve bubbling, where the temperature of the first water bath 211 is set to 35℃, and the nitrogen and steam mixed gas is led out through the outlet conduit; Also set the nitrogen flow rate of the third mass flowmeter to 12.5 ml / min and introduce nitrogen into the formaldehyde gas generation tube to the paraformaldehyde powder bed layer 223, where the temperature of the second water bath 221 is set to 30℃. Set the oxygen (39% oxygen + 61% nitrogen) flow rate of the first flowmeter 112 to 25 ml / min for oxygen supply. Oxygen, steam, and formaldehyde gas are converged at the four-way valve 13 to obtain the formaldehyde mixed gas required for the reaction (the calculated formaldehyde gas concentration R is 149.25 ppm, and the relative humidity RH of the steam branch is 25.45%); Introduce the formaldehyde mixed gas into the chromatograph 44 for detection and confirmation, and complete the preparation work after the components of the formaldehyde mixed gas are stable for 10 minutes.

[0049] (3) Catalyst performance evaluation: Control the three-way reaction valve 122 to introduce the mixed gas into the reaction tube 35, and the formaldehyde mixed gas is introduced into the reaction tube 35 at a space velocity of 30000 mL / (g*h) for about 5 minutes; Then, set the temperature control program of the tube furnace 33 as follows: the heating rate is 5℃ / min, and it is kept warm for 60 min at each stage of 30℃ / 50℃ / 70℃ / 90℃ / 110℃ / 130℃, and then the program stops heating; The chromatograph 44 collects the real-time concentration data of each component during the whole process of formaldehyde catalytic oxidation.

[0050] (4) Sample replacement: Set the flow rates of the three flow meters 112, 226, and 216 to 0 ml / min in sequence, and disconnect the oxygen and nitrogen supplies. Control the three reaction three-way valves 122 to control the pipeline of the device to bypass the reaction tube 35 and the chromatograph 44, and be in a direct evacuation mode. When the temperature of the fourth temperature sensor T4 in the tube furnace 33 is lower than 50 °C, open the tube furnace 33, remove the reaction tube 35, and remove the quartz wool bed layer 351 and the catalytic material bed layer 352 (rushing out reversely from the reaction outlet tube 354 with water flow). After cleaning and drying, reserve them for use. Repeat steps (1)-(3), replace with new reaction tube 35, quartz wool bed layer 351 and catalytic material bed layer 352, and restart the catalyst performance evaluation.

[0051] (5) Data processing and analysis: Extract the data and draw the temperature-formaldehyde conversion rate curves of each catalyst. The conversion rate curves of the three catalysts in this embodiment are as Figure 7 shown. It can be found that the catalyst has the best catalytic activity under the calcination condition of 700 °C.

[0052] As Figure 6 shown, closing the second flow meter 216 and the supply valve 217 can realize the evaluation of the formaldehyde catalytic performance of the catalyst.

[0053] In summary, the formaldehyde mixture provided by this device has the characteristics of low cost and stable components, and can conveniently and quickly realize the evaluation of the catalytic oxidation performance of formaldehyde catalysts.

[0054] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An apparatus for evaluating the catalytic performance of a formaldehyde oxidation catalyst, characterized in that, It includes a gas supply unit (1), a gas generation unit (2), and a formaldehyde reaction unit (3). The gas generation unit (2) includes a steam generation module (21) and a formaldehyde gas generation module (22). The steam generation module (21) includes a first water bath (211) and a steam generation pipe (212); the steam generation pipe (212) is a sealed tube and its lower end is immersed in the first water bath (211). Distilled water (213) is contained in the steam generation pipe (212). The upper end of the steam generation pipe (212) is connected through to a first inlet conduit (214), and the lower end of the first inlet conduit (214) is immersed below the liquid level of the distilled water (213) in the steam generation pipe (212). A first outlet conduit (215) and a pressure sensor P are also provided at the top of the steam generation pipe (212). The formaldehyde gas generation module (22) includes a second water bath (221) and a formaldehyde generation pipe (222); the formaldehyde generation pipe (222) is a sealed tube and its lower end is immersed in the second water bath (221). A paraformaldehyde powder bed (223) is provided at the inner bottom of the formaldehyde generation pipe (222). The formaldehyde generation pipe (222) is provided with a second inlet conduit (224) that penetrates into it from the top. The lower end of the second inlet conduit (224) is a conical opening (2241) and extends into the interior of the paraformaldehyde powder bed (223). A second outlet conduit (225) for leading out formaldehyde gas is also provided at the top of the formaldehyde generation pipe (222). The gas supply unit (1) includes an oxygen cylinder (11), a nitrogen cylinder (12), a three-way valve (122), and a four-way valve (13). The oxygen cylinder (11) is connected to one end of the four-way valve (13) through a first pipe. An oxygen main valve (111) and a first flow meter (112) are provided on the first pipe. The nitrogen cylinder (12) is connected to one end of the three-way valve (122) through a second pipe. A nitrogen main valve (121) is provided on the second pipe. The other two ends of the three-way valve (122) are respectively provided with a third pipe and a fourth pipe. A second flow meter (216) is provided on the third pipe. The other end of the third pipe is connected to the first inlet conduit (214). A third flow meter (226) is provided on the fourth pipe. The other end of the third pipe is connected to the second inlet conduit (224). The other three ends of the four-way valve (13) are respectively connected to a fourth pipe, a fifth pipe, and a sixth pipe. The other end of the fourth pipe is connected to the upper end of the first outlet conduit (215). A supply valve (217) is provided on the fourth pipe. The other end of the fifth pipe is connected to the upper end of the second outlet conduit (225). The sixth pipe is connected to the formaldehyde reaction unit (3). The formaldehyde reaction unit (3) includes a first reaction three-way reversing valve (32), a tubular heating furnace (33), and a reaction tube (35); the tubular heating furnace (33) has a cylindrical cavity inside, and a heating wire (34) and a fourth temperature sensor T4 are arranged in the cavity. The reaction tube (35) includes a reaction inlet tube (355) and a reaction outlet tube (354). The reaction inlet tube (355) and the reaction outlet tube (354) form a U-shaped reaction tube (35). The lower half of the reaction tube (35) is located inside the cavity of the tubular heating furnace (33). The U-shaped bottom of the reaction tube (35) is reduced in diameter. A quartz wool bed layer (351) is arranged at the bottom side of the reaction inlet tube (355), and a catalytic material bed layer (352) is arranged on the quartz wool bed layer (351). A sleeve (353) is arranged inside the reaction inlet tube (355), and a third temperature sensor T3 is arranged inside the sleeve (353). The lower ends of the sleeve (353) and the third temperature sensor T3 are both located inside the catalytic material bed layer (352). The first reaction three-way reversing valve (32) is connected to the upper end of the reaction inlet tube (355) through a tenth tube, and the other end of the first reaction three-way reversing valve (32) is connected to the sixth tube in a through manner; The formaldehyde reaction unit (3) is connected to a chromatographic detection unit (4), and the chromatographic detection unit (4) is used to detect the components of the tail gas after catalysis. An exhaust unit (5) for exhausting waste gas is connected to the chromatographic unit.

2. The device for evaluating the catalytic performance of a formaldehyde oxidation catalyst according to claim 1, characterized in that, The chromatographic detection unit (4) includes a chromatograph (44). An air inlet end (43) and an air outlet end (45) are arranged on the chromatograph (44). The air inlet end (43) is connected to the reaction outlet tube (354) through a seventh tube. The seventh tube is divided into two disconnected sections, and the two sections of the seventh tube are connected through a third reaction three-way reversing valve (42). One end of the first reaction three-way reversing valve (32) away from the sixth tube and the reaction inlet tube (355) is connected to an eighth tube. The upper end of the eighth tube is connected to a second reaction three-way reversing valve (41). The second reaction three-way reversing valve (41) is connected to the end of the third reaction three-way reversing valve (42) away from the seventh tube through a ninth tube. The air outlet end (45) is connected to an exhaust three-way pipe (46). The other two ends of the exhaust three-way pipe (46) are respectively connected to the second reaction three-way reversing valve (41) and the exhaust unit (5).

3. The device for evaluating the catalytic performance of a formaldehyde oxidation catalyst according to claim 2, wherein The exhaust unit includes a soap film flow tube (52). An exhaust port (51) and a soap solution balloon (53) are respectively arranged at the upper and lower parts of the soap film flow tube (52). A saponifying solution (531) is contained in the soap solution balloon (53). Volume scales are arranged on the tube wall of the soap film flow tube (52). A soap film flow tube air inlet (54) is arranged on the lower side wall of the soap film flow tube (52). One end of the exhaust three-way pipe (46) connected to the exhaust unit (5) is connected to the soap film flow tube air inlet (54).

4. The device for evaluating the catalytic performance of a formaldehyde oxidation catalyst according to claim 3, wherein A first pipeline heating tape (2151) is wound around the fourth pipe connected to the first outlet conduit (215), a second pipeline heating tape (2251) is wound around the fifth pipe connected to the second outlet hole conduit, a third pipeline heating tape (31) is wound around the sixth pipe between the four-way valve (13) and the formaldehyde reaction unit (3), a fourth pipeline heating tape (36) is wound around the seventh pipe connected to the reaction outlet pipe (354), and a first temperature sensor T1 and a second temperature sensor T2 are respectively arranged on the third pipeline heating tape (31) and the fourth pipeline heating tape (36).

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