CN114789051B - Desulfurization, denitrification and vanadium carbon catalyst regeneration method for reducing dioxin release - Google Patents

Desulfurization, denitrification and vanadium carbon catalyst regeneration method for reducing dioxin release Download PDF

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CN114789051B
CN114789051B CN202210342678.2A CN202210342678A CN114789051B CN 114789051 B CN114789051 B CN 114789051B CN 202210342678 A CN202210342678 A CN 202210342678A CN 114789051 B CN114789051 B CN 114789051B
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CN114789051A (en
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黄张根
曾泽泉
丁肖肖
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Shanxi Institute of Coal Chemistry of CAS
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Abstract

The application belongs to the technical field of desulfurization and denitrification vanadium carbon catalyst regeneration, and provides a desulfurization and denitrification vanadium carbon catalyst regeneration method for reducing dioxin release, which aims to solve the problem that dioxin is secondarily released in the vanadium carbon catalyst regeneration process to form environmental risks. Heating 5% -20% of oxygen-containing inert gas, then introducing the heated inert gas into a regenerator filled with vanadium-carbon catalyst, and controlling the regeneration temperature to be 250-350 ℃ to oxidize dioxin; switching the atmosphere to an oxygen-free inert atmosphere, and regenerating at 400-550 ℃ for 30min; when the proper amount of oxygen is mixed at the temperature of 250-350 ℃, the dioxin can be effectively oxidized, and meanwhile, the active coke is not excessively ablated, so that the emission of the dioxin is obviously reduced while the active coke is effectively regenerated. If the temperature is too high or the oxygen content is too high, the carbon loss increases and the regeneration yield decreases.

Description

Desulfurization, denitrification and vanadium carbon catalyst regeneration method for reducing dioxin release
Technical Field
The application belongs to the technical field of desulfurization and denitrification vanadium carbon catalyst regeneration, and particularly relates to a desulfurization and denitrification vanadium carbon catalyst regeneration method for reducing dioxin release.
Background
Dioxins are a class of chlorine-containing polycyclic aromatic hydrocarbon organic compounds, and are a generic name for polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCDDs). Is one of 12 typical persistent organic pollutants controlled by the first lot of the Stockhol convention, has high melting point, stable chemical property, extremely strong carcinogenicity and teratogenicity, is the most toxic substance on the earth at present, has strong fat solubility, can be accumulated in organisms for a long time, and causes serious harm to human health and living environment. Currently, dioxins are mainly derived from chlorine-containing production industries such as metal production, waste combustion, power generation and heating, mineral product production, and the like. Wherein, the steel production accounts for about 55 percent and more than 90 percent of the total dioxin emission, and the dioxin comes from the sintering process, thus becoming the important weight of controlling and controlling the dioxin emission.
The dry method integrated removal technology of the carbon-based catalyst is the most common method for treating sintering flue gas in Chinese iron and steel factories because the technology does not consume water, can recycle pollutants and can remove various pollutants simultaneously, and the technology mainly comprises a reaction part and a regeneration part, wherein NOx is subjected to NH in a reactor 3 Reduction to N 2 Clean emission, dioxin and SO 2 And heavy metals are adsorbed on the carbon-based catalyst, the carbon-based catalyst with the adsorbed pollutants is sent to a regenerator for desorption and regeneration, SO 2 The method can realize sulfur reclamation during regeneration, and the regenerated carbon-based catalyst can be recycled, so that the process running cost is obviously reduced. Dioxin may be directly desorbed under the condition of high regeneration temperature (300-500 ℃) and has the risk of recontamination.
The prior art mainly focuses on the regeneration performance of the adsorption saturated vanadium carbon catalyst, and lack of attention and effective means for controlling dioxin in the regeneration process, so that the dioxin is secondarily released in the vanadium carbon catalyst regeneration process, and the environmental risk is formed.
Disclosure of Invention
Aiming at the defects of the prior art, the application provides a desulfurization, denitrification and vanadium-carbon catalyst regeneration method for reducing dioxin release. The regeneration method for controlling the regeneration process of the active coke to release dioxin by adjusting the regeneration atmosphere and the regeneration temperature.
The application is realized by the following technical scheme: a desulfurization, denitrification and vanadium carbon catalyst regeneration method for reducing dioxin release is characterized by comprising the following steps of: the regeneration atmosphere and the regeneration temperature are regulated to control the regeneration process of the active coke to release dioxin, and the specific steps are as follows:
(1) Introducing 5-20 vol% of oxygen-containing inert gas into a regenerator filled with vanadium-carbon catalyst after heating, controlling the regeneration temperature to 250-350 ℃ for dioxin oxidation, and keeping for 1-2h; controlling the gas flow to be 200mL/min;
(2) Switching the atmosphere to an oxygen-free inert atmosphere, controlling the gas flow to be 200mL/min, and regenerating at 400-550 ℃ for 30min;
(3) And cooling the regenerated vanadium-carbon catalyst to be less than or equal to 100 ℃ in an inert atmosphere to obtain the regenerated vanadium-carbon catalyst.
The inert gas is as follows: n (N) 2 . Preferably: the oxygen content in the oxygen-containing inert gas was 15 vol%.
The regeneration reaction time in step (1) is preferably 1h.
The specific surface area of the regenerated catalyst is effectively recovered compared with that of the regenerated catalyst in an inert atmosphere. The pore volume of the regenerated catalyst can be effectively recovered compared with the pore volume of the regenerated catalyst in an inert atmosphere. In the regeneration process, the oxygen-containing regeneration section mainly generates substances such as maleic anhydride and the like. The surface of the regenerated catalyst is remained with small molecular substances such as toluene.
The beneficial effects of the application are as follows: in the conventional active coke regeneration process, inert atmosphere is used in the whole process, so that dioxin cannot be effectively decomposed, and a large amount of dioxin is released, so that secondary pollution is caused. When the proper amount of oxygen is mixed at the temperature of 250-350 ℃, the dioxin can be effectively oxidized, and meanwhile, the active coke is not excessively ablated, so that the emission of the dioxin is obviously reduced while the active coke is effectively regenerated. Researches show that when the temperature is 250-350 ℃, dioxin can be effectively degraded only by introducing 5-20% of oxygen, but the vanadium-carbon catalyst has no obvious reaction with oxygen at the moment, so that the regeneration yield of the vanadium-carbon catalyst and the efficient degradation of dioxin can be considered. If the temperature is too high or the oxygen content is too high, the carbon loss increases and the regeneration yield decreases.
Drawings
FIG. 1 is a GCMS product analysis of the gases during regeneration for example 3 and comparative example 1;
FIG. 2 is a GCMS product analysis of the catalyst surface during regeneration of example 3 and comparative example 1;
FIG. 3 is a graph of breakthrough curve and adsorption capacity and conversion for a catalyst; a is a penetration curve; b is adsorption capacity and conversion;
FIG. 4 is a graph showing the relationship between pore structure and dioxin removal rate; in the figure: (a) is specific surface area and adsorption capacity; (b) is specific surface area and conversion; (c) is the external specific surface area and adsorption capacity; (d) external specific surface area and conversion; (e) is the outer pore volume and adsorption capacity; (f) is the external pore volume and conversion;
FIG. 5 is an electron micrograph (1000) of a regenerated catalyst; in the figure: (a) fresh; (b) RE-1; (c) RE-2; (d) RE-3; (e) RE-4; (f) RE-O-15;
FIG. 6 is a Raman analysis of regenerated catalyst;
FIG. 7 is a peak-split fit of Raman;
FIG. 8 shows XPS analysis results of a catalyst;
FIG. 9 is V 5+ A relationship with the catalyst to dioxin conversion;
FIG. 10 is an in situ infrared analysis of a catalyst;
fig. 11 is a diagram showing a conversion route of dioxin in the regeneration process.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments; all other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, the disclosure of which is incorporated herein by reference as is commonly understood by reference.
Those skilled in the art will recognize that equivalents of the specific embodiments described, as well as those known by routine experimentation, are intended to be encompassed within the present application.
The experimental methods in the following examples are conventional methods unless otherwise specified. The instruments used in the following examples are laboratory conventional instruments unless otherwise specified; the experimental materials used in the examples described below, unless otherwise specified, were purchased from conventional biochemical reagent stores.
Example 1: preparing a vanadium-carbon catalyst: taking the deashed active coke as a carrier, and adopting superPreparation of vanadium-carbon catalyst V by acoustic isovolumetric impregnation method 2 O 5 AC, weighing 12.8678 g NH 4 VO 3 And 21.5 g H 2 C 2 O 4 ·2H 2 O in a beaker, water 60 mL is added with mixing, and the mixture is stirred into a mixed aqueous solution, and the solution is yellow-brown. Transferring the solution into a water bath kettle with the temperature of 60 ℃, rapidly stirring, gradually changing the color of the aqueous solution from yellow-brown to deep blue, transferring the solution into a 100 mL volumetric flask after the solution is cooled, and keeping the volume for later use. 2ml of the prepared vanadium solution is measured by a pipette, deionized water is added into the solution to dilute the solution to 4ml, then 4g of active coke is immersed in the solution, and after stirring, the solution is dissolved by ultrasonic assistance for 1 hour, and the ultrasonic power is 60W. Standing at room temperature for 5 hr, drying at 50deg.C for 5 hr, drying at 110deg.C for 10 hr, and drying at N 2 Calcining at 500 ℃ for 5 hours, and pre-oxidizing for 5 hours in an air atmosphere at 250 ℃ to obtain the vanadium-carbon catalyst.
Preparing a vanadium carbon catalyst containing dioxin saturation: the obtained vanadium-carbon catalyst is treated at 120 ℃,200mL/min and 10% O 2 ，540mg/m 3 And (3) carrying out an adsorption experiment under the condition of dioxin, and intermittently measuring the content of the dioxin in the tail gas of the reactor until the content of the dioxin in the tail gas is the same as the content of the air inlet, so as to obtain the saturated vanadium-carbon catalyst containing the dioxin.
Desulfurization and denitrification vanadium carbon catalyst regeneration for reducing dioxin release: the obtained vanadium-carbon catalyst containing dioxin saturation is regenerated in situ, and the gas is switched to 200mL/min and 5% O 2 ，N 2 As a balance gas. The regenerator temperature was adjusted to 300 ℃ and maintained for 1 hour, the amount of released dioxin was measured at the tail of the reactor, and the amount of released dioxin was measured by GC-MS.
The gas in regeneration is switched to 200mL/min N 2 The temperature was continuously raised to 450℃and maintained for 30 minutes, and the release amount of dioxin was continuously measured at the tail of the reactor, and the release amount of dioxin was measured by GC-MS. At this time, the conversion rate of dioxin regeneration was 61.39%.
And (3) carrying out mass balance on the reacted vanadium-carbon catalyst to obtain the vanadium-carbon catalyst with the regeneration yield of 98.55%. The specific surface area of the catalyst is 132.09m 2 Per gram, pore volume of 0.117cm 3 /g。
Example 2: example 2 is substantially the same as example 1 except that: gas in regeneration of the desulfurization, denitrification and vanadium carbon catalyst for reducing dioxin release is switched to 200mL/min, and O is 10% 2 ，N 2 As a balance gas. In the process, the regeneration conversion rate of dioxin is 65%, and the regeneration yield of the vanadium-carbon catalyst is 98.29%. The specific surface area of the catalyst is 180.97m 2 Per gram, pore volume of 0.192cm 3 /g。
Example 3: example 3 essentially the same as example 1, except that the gas in the regeneration of the desulfurization, denitrification and vanadic catalyst for reducing dioxin release was switched to 200mL/min,15% O 2 ，N 2 As a balance gas. In the process, the regeneration conversion rate of dioxin is 70.07%, and the regeneration yield of the vanadium-carbon catalyst is 96.83%. The specific surface area of the catalyst is 210.27m 2 Per gram, pore volume of 0.210cm 3 /g。
Comparative example 1: the dioxin-containing saturated vanadium carbon catalyst prepared in example 1 was used in an amount of 200mL/min N 2 In the atmosphere, the temperature was raised to 450℃and maintained for 1h. The regeneration conversion rate of dioxin in the process is 20.88%, and the regeneration yield of the vanadium-carbon catalyst is 98.55%. The specific surface area of the catalyst is 139.01m 2 Per gram, pore volume of 0.112cm 3 /g。
Comparative example 2: the dioxin-containing saturated vanadium carbon catalyst prepared in example 1 was treated at 200mL/min with 1% O 2 ，N 2 As an equilibrium gas, the temperature was raised to 450℃and maintained for 1h. The regeneration conversion rate of dioxin in the process is 52.70%, and the regeneration yield of the vanadium-carbon catalyst is 78.75%.
Comparative example 3: comparative example 3 is substantially the same as comparative example 2 except that the oxygen content in the gas was 3% O at 200mL/min 2 ，N 2 As an equilibrium gas, the temperature was raised to 450℃and maintained for 1h. The regeneration conversion rate of dioxin in the process is 59.11%, and the regeneration yield of the vanadium-carbon catalyst is 52.28%.
Comparative example 4: comparative example 4 is substantially the same as comparative example 3, except that the oxygen content in the gas is that200mL/min，5% O 2 ，N 2 As an equilibrium gas, the temperature was raised to 450℃and maintained for 1h. The regeneration conversion rate of dioxin in the process is 64.18%, and the regeneration yield of the vanadium-carbon catalyst is 32.58%.
The conversion of dioxin and the carbon loss of the catalyst during the regeneration of the examples and comparative examples were counted, and the results are shown in table 1, and the pore structure data of the regenerated catalyst are shown in table 2.
Table 1 conversion of dioxins and carbon loss of examples and comparative examples
Table 2 pore structure data for catalysts in examples
By combining the table 1 and the table 2, it is obvious that the regeneration method of the application can effectively realize the conversion of dioxin in the regeneration process, the conversion rate can reach more than 61%, and the direct emission of dioxin is reduced. And the regenerated product is polycyclic aromatic hydrocarbon with small molecules and smaller toxicity, so that the degradation of dioxin is effectively realized. The pore structure of the catalyst obtained by the regeneration method is obviously improved compared with the catalyst regenerated in inert atmosphere, so that dioxin can be effectively adsorbed, and the subsequent removal rate of dioxin is improved.
Experimental example: performing activity evaluation on the prepared regenerated catalyst and regeneration condition optimization experiment
The method for detecting the activity of the regenerated catalyst by taking dibenzofuran DBF as a mode pollutant comprises the following specific detection method: in the cleaning system, DBF steam is introduced into N at 80 DEG C 2 Preventing condensation of steam; DBF is kept at 110 ℃, the total concentration of reactant gas is 200ml/min, and the total concentration of DBF entering the reactant is 540 mg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the 10% oxygen, nitrogen balance. The fixed bed reactor was charged with 0.2. 0.2 g catalyst at 120 ℃. At the same time, the catalyst was examined under the same air intake conditions at 300 ℃ in stripsOxidation properties under the part. The concentration of DBF and its byproducts was determined using gas chromatography-mass spectrometry (GCMS-QP 2010SE, shimadzu).
In the cyclic regeneration experiment, the catalyst used was regenerated for 60 min under nitrogen atmosphere at 450℃and the regenerated catalyst was RE-1, RE-2, RE-3 and RE-4, respectively, according to the corresponding regeneration times. In addition, the ethanol is used for collecting tail gas, and byproducts possibly generated in the regeneration process are detected.
Introduction of O during regeneration 2 (0%, 5%, 10%, 15%) was subjected to an optimized regeneration experiment, regenerated for 60 min in an O2-containing atmosphere at 300℃and then regenerated for 30min in an N2 atmosphere at an elevated temperature of 450 ℃. The resulting samples were RE-O-0, RE-O-5, RE-O-10 and RE-O-15, respectively, depending on the introduced oxygen content. The tail gas was collected and subjected to GC-MS analysis. The regenerated catalyst is subjected to soxhlet extraction 24, h to obtain a non-volatile intermediate which may remain on the catalyst surface.
Using N 2 Adsorption isotherms (Quantachrome Instrument Corp, USA), scanning electron microscopy (SEM, JSM-7001F, JEOL, japan), raman (Raman, thermo Scientific DXR, USA), x-ray photoelectron spectroscopy (XPS, kratos Analytical Ltd, UK), elemental analysis (EA, elementarAnalysen system GmbH, germany), inductively coupled plasma optical emission spectroscopy (ICP-OES, perkin Elmer, USA). In situ diffusion fourier transform infrared spectroscopy (DRIFTS) experiments were performed on a VERTEX 80v fourier transform infrared spectrometer.
The breakthrough curves and adsorption capacities of the fresh catalyst and regenerated catalyst are shown in fig. 3. It can be seen from fig. 3a that the penetration time becomes shorter as the number of cycles increases. FIG. 3b shows the conversion of dioxin and the adsorption capacity integrated with the breakthrough curve of the regenerated catalyst, from which it can be seen that the DBF adsorption was in turn fresh (96.76 mg/g) > RE-1 (75.82 mg/g) > RE-2 (53.14 mg/g) > RE-3 (37.94 mg/g) > RE-4 (30.99 mg/g), indicating that thermal regeneration did not restore the catalyst adsorption to DBF. The adsorption amount of RE-4 is 1/3 lower than that of fresh AC. As the number of regeneration cycles increases, the adsorption capacity and conversion of dioxin by the catalyst gradually decrease. This may be related to the change in physicochemical properties of the catalyst during regeneration.
The pore structure data of the circularly regenerated catalyst is shown in Table 3. As can be seen from table 3, the specific surface area and pore volume of the catalyst drastically decrease with the increase of the number of regeneration cycles, while the average pore diameter of the catalyst gradually increases with the increase of the number of cycles, and the micropore specific surface area of the catalyst is completely disappeared when the fourth cycle is performed, and the average pore diameter of the catalyst is almost twice as large as that of the fresh catalyst, which may be caused by the accumulation of the regenerated product difficult to be desorbed in the pores of the catalyst, and the heat regeneration treatment may also cause unstable pore collapse. The small specific surface area means fewer adsorption sites, which is also responsible for the gradual decrease in adsorption performance of the cyclically regenerated catalyst.
TABLE 3 pore structure data for cyclically regenerated catalysts
Since dioxin belongs to a macromolecular structure, it is considered that it is mainly adsorbed in a mesoporous structure, and in order to further analyze the influence of the pore structure on dioxin removal, the pore structure of the regenerated catalyst and the dioxin removal rate are related, and the result is shown in fig. 4. From FIG. 4, it can be seen that the adsorption capacity of the catalyst to dioxin and the external specific surface area (R 2 =0.884) and an outer pore volume (R 2 =0.889), which means that the mesoporous structure dominates the adsorption of dioxin by the catalyst. It can also be seen that the conversion is related to the external specific surface area (R 2 =0.981) and an outer pore volume (R 2 =0.979) also has a good correlation, further illustrating that the mesoporous structure has an important role for catalyst removal of dioxins.
The electron microscope scanning is carried out on the catalyst obtained after different regeneration times, the morphology graph is shown in fig. 5, and from the graph, the micropores of the regenerated catalyst are gradually reduced compared with the fresh catalyst, which is consistent with the result of pore diameter analysis, and meanwhile, the surface of the regenerated catalyst is gradually roughened along with the increase of the regeneration times.
The structure of the regenerated catalyst was further analyzed by raman spectroscopy. As a result, as shown in FIG. 6, two peaks, each at 1600cm, can be seen in FIG. 6a -1 G bands of (2) which are ascribed to sp in the graphite flake 2 Hybrid stretching vibration, and located at 1360cm -1 D band of (c), which is attributed to defects of disordered carbon. And further carrying out peak-splitting fitting on the D band to obtain D1, D3 and D4, and the result is shown in FIG. 7. Wherein D1 represents a highly ordered carbonaceous material and C-C between aromatic rings and an aromatic material having not less than 6 rings. D3 represents disordered carbon in the 3-5 ring aromatic ring, including fragments in organic molecules and functional groups. D4 represents a highly disordered carbonaceous substance. (I) D3 + I D4 )/I G Typically used to represent the catalytic activity of a carbon-based catalyst, as can be seen in FIG. 6b, (I) D3 + I D4 )/I G This means that the regenerated catalyst becomes progressively ordered as the regeneration cycle increases, further indicating fewer active sites on the regenerated catalyst, which is detrimental to the catalytic activity of the catalyst.
The elemental analysis results of the catalyst are shown in table 4, and it can be seen from the table that the carbon element of the catalyst gradually increases with the increase of the number of regenerations, and the oxygen content slightly decreases with the increase of the number of regenerations of the catalyst, which may be caused by the decomposition of some unstable functional groups such as carboxyl groups and acid anhydrides on the surface of the catalyst with the regenerative heat treatment. As can be seen from table 4, the carbon element and the oxygen element thereof increased and decreased, respectively, with the increase in the number of regenerations, which is consistent with the results of the elemental analysis.
Table 4: elemental analysis results of the catalyst
In order to further analyze the surface chemistry of the regenerated catalyst, XPS analysis was performed thereon, and the analysis results are shown in fig. 8; and peak-split fits were performed on C1s, V2p and O1 s. The results are shown in Table 5, and the C1s is divided into four groupsPeak of 284.6eV ascribed to sp 2 -C and sp 3 -C peak of C, 286eV ascribed to C-O peak of phenol and ether, 287.3eV ascribed to c=o peak of carbonyl and quinone and 288.6eV ascribed to o=c-O peak of anhydride, carboxyl and ester groups. As can be seen from table 5, the C-C and C-O contents increase with the number of regenerations, and the c=o and o=c-C contents decrease, which may be caused by the decomposition of oxygen-containing functional groups of some anhydrides, which are unstable themselves, with the regeneration operation, and the decomposition of these oxygen-containing functional groups is unfavorable for the adsorption of dioxin by the catalyst.
The V element content in the XPS results is higher than that in the ICP, indicating that the active metal vanadium is mainly distributed on the surface of the catalyst, while it can be seen that the V content on the surface of the catalyst decreases from 8.05% to 6.59% with the increase of the regeneration times, which is probably caused by that the product which is difficult to volatilize and is generated in the regeneration process gradually accumulates on the surface of the catalyst with the increase of the regeneration times, covering the active sites of the catalyst.
Dividing V2p into V of 516eV 4+ And V of 517.3eV 5+ Two peaks. As can be seen from the table, as the number of regenerations increases, V 4+ Content is increased and V 5+ The reduction of the content of the high-valence vanadium is unfavorable for the oxidation of dioxin by the catalyst. This relationship can be further verified from FIG. 9, which shows the conversion of dioxin by the catalyst versus V 5+ There is a positive correlation between them, explaining V 5+ Is a major factor in oxidizing dioxin.
Table 5: peak-split fitting results of C1s, V2p and O1s
O1s was divided into three peaks. Wherein 530.4 eV is a lattice oxygen species O 2- (O β ) 532.1 eV is surface adsorbed O 2- , O - or O 2 2- Species (O) α ) 533.7. 533.7 eV is an acidic radical or-OH (O) in adsorption γ ). As can be seen from Table 5, the lattice oxygen gradually increases with the number of regenerationsGradually decreasing, but lattice oxygen is critical to the catalytic activity of the catalyst, so that a decrease in lattice oxygen content also results in a decrease in regenerated catalyst activity.
Analysis of the regenerated product is critical to qualitative and quantitative analysis of dioxins during regeneration. RE-O-15 was a two-stage in situ infrared analysis of oxygen-containing regeneration, as can be seen in FIG. 10 at 1198cm -1 C-O vibration peak ascribed to phenolate at 1240cm -1 The C-O stretching vibration peaks, which are attributed to the surface alcoholates, gradually increase as the reaction proceeds, indicating that phenolates and alcoholates are gradually formed. 1377cm -1 The symmetrical bending vibration peak of CH3-Ar is shown. 1394cm -1 C=c vibration peak. Attributing to 1443cm -1 The location being of asymmetric-COO - The stretching vibration peak also appears and gradually increases as the reaction proceeds. 1730 cm -1 , 1744 cm -1 and 1760 cm -1 To account for c=o stretching vibrations in typical cyclic maleic anhydride and phthalic acid. This is consistent with the analysis results of GC-MS for RE-O-15. This is probably due to the gradual oxidation of dioxin to intermediates such as maleic anhydride, acetate and phthalic acid during the reaction in an oxygen-containing atmosphere, which eventually decompose to CO 2 And H 2 O. 1443cm in situ IR analysis of RE-1 as compared to RE-O-15 -1 and 1240 cm -1 Also increasing, meaning that dioxin is also gradually oxidized to part of the carbonate species during the reaction, except for relatively small amounts, which is consistent with the GC-MS results for RE-1.
The conversion path of dioxin in the regeneration process can be deduced through the analysis results of in-situ infrared and GC-MS. And the qualitative and quantitative relation of dioxin conversion in the regeneration process can be obtained. As shown in fig. 11, only 20.88% of dioxin is decomposed during the regeneration in an inert atmosphere, and most of dioxin is directly released in the form of dioxin, thereby generating secondary pollution. In the case of oxygen-containing regeneration, the conversion rate of dioxin is increased to 70.07%, which is about 3.5 times that of the regeneration in an inert atmosphere. The two regeneration modes follow the same conversion path, and dibenzofuran (DBF, model compound of dioxin) is adsorbed on the vanadium-carbon catalyst through oxygen atomsIs a L acid site of (C). DBF adsorbed on the catalyst forms DBF-OH by oxidation of the C-H bond with the help of active oxygen, DBF-OH forms ethynylbenzofuran by a continuous "perlink elimination" reaction, ethynylbenzofuran further forms benzofuran (DF) by activation of the C-C bond, DF forms styrene and other oxyalkyl compounds by further opening the furan ring and benzene ring, styrene and oxygen-containing compounds are reacted in the presence of V 2 O 5 Acid anhydride substances such as maleic anhydride and the like are generated under the action of the catalyst, and are finally decomposed into CO2 and H2O. However, some heavy aromatic substances which are not completely decomposed are difficult to desorb from the surface of the catalyst, so that the heavy aromatic substances remain and accumulate in the pore channels of the catalyst with the increase of the regeneration times, but the phenomenon can be improved by the oxygen-containing regeneration mode.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application.

Claims (4)

1. A desulfurization, denitrification and vanadium carbon catalyst regeneration method for reducing dioxin release is characterized by comprising the following steps of: the regeneration atmosphere and the regeneration temperature are regulated to control the regeneration process of the active coke to release dioxin, and the specific steps are as follows:
(1) Introducing 5-20 vol% of oxygen-containing inert gas into a regenerator filled with vanadium-carbon catalyst after heating, controlling the regeneration temperature to 250-350 ℃ for dioxin oxidation, and keeping for 1-2h; controlling the gas flow to be 200mL/min;
(2) Switching the atmosphere to an oxygen-free inert atmosphere, controlling the gas flow to be 200mL/min, and regenerating at 400-550 ℃ for 30min;
(3) And cooling the regenerated vanadium-carbon catalyst to be less than or equal to 100 ℃ in an inert atmosphere to obtain the regenerated vanadium-carbon catalyst.
2. The desulfurization, denitrification and vanadium-carbon catalyst regeneration method for reducing dioxin release according to claim 1, which is characterized in that: the inert gas is as follows: n (N) 2 。
3. The desulfurization, denitrification and vanadium-carbon catalyst regeneration method for reducing dioxin release according to claim 2, which is characterized in that: the oxygen content in the oxygen-containing inert gas was 15 vol%.
4. A desulfurization and denitrification vanadium catalyst regeneration method for reducing dioxin release according to claim 3, which is characterized in that: the regeneration reaction time in the step (1) is 1h.
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Citations (3)

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Publication number Priority date Publication date Assignee Title
CN1817408A (en) * 2005-12-21 2006-08-16 中国科学院山西煤炭化学研究所 Regeneration of vanadium carbon base desulfurizer
CN101259417A (en) * 2008-04-15 2008-09-10 中国科学院山西煤炭化学研究所 Regeneration method of sulphur absorption V2O5/AC catalytic adsorption agent
CN101391178A (en) * 2008-10-24 2009-03-25 中国科学院山西煤炭化学研究所 Method for removing mercury in flue gas using V2O5/carbon material catalyst

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1817408A (en) * 2005-12-21 2006-08-16 中国科学院山西煤炭化学研究所 Regeneration of vanadium carbon base desulfurizer
CN101259417A (en) * 2008-04-15 2008-09-10 中国科学院山西煤炭化学研究所 Regeneration method of sulphur absorption V2O5/AC catalytic adsorption agent
CN101391178A (en) * 2008-10-24 2009-03-25 中国科学院山西煤炭化学研究所 Method for removing mercury in flue gas using V2O5/carbon material catalyst

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