CN113209816A

CN113209816A - Catalyst grading method for catalytic oxidation of sulfur-containing VOCs and method for catalytic oxidation of sulfur-containing VOCs

Info

Publication number: CN113209816A
Application number: CN202010451644.8A
Authority: CN
Inventors: 尹树孟; 于辉; 单晓雯; 程龙军; 陶彬
Original assignee: China Petroleum and Chemical Corp; Sinopec Qingdao Safety Engineering Institute
Current assignee: China Petroleum and Chemical Corp; Sinopec Qingdao Safety Engineering Institute
Priority date: 2020-01-21
Filing date: 2020-05-25
Publication date: 2021-08-06
Also published as: CN113209774A

Abstract

The invention relates to the technical field of VOCs treatment, in particular to a catalyst grading method for catalytic oxidation of sulfur-containing VOCs and a method for catalytic oxidation of sulfur-containing VOCs. The catalyst grading method for catalytic oxidation of sulfur-containing VOCs comprises the following steps: and (2) enabling the mixed reaction gas obtained after the sulfur-containing VOCs and the oxygen-containing gas are mixed to pass through n serial catalyst bed layers, wherein the n serial catalyst bed layers are a desulfurization bed layer and a first catalyst bed layer in sequence according to the contact sequence of the mixed reaction gas and the catalyst bed layers, and n is more than or equal to 3. According to the invention, different types of catalysts are applied in a layered grading manner, so that the layered and efficient removal of multi-component VOCs materials can be realized, the use cost of the catalyst is reduced, and the catalyst has the characteristic of efficient fine removal.

Description

Catalyst grading method for catalytic oxidation of sulfur-containing VOCs and method for catalytic oxidation of sulfur-containing VOCs

Technical Field

The invention relates to the technical field of VOCs treatment, in particular to a catalyst grading method for catalytic oxidation of sulfur-containing VOCs and a method for catalytic oxidation of sulfur-containing VOCs.

Background

With the stricter requirements of national standards on the discharge of VOCs and characteristic pollutants thereof, a Catalytic Oxidation (CO) method for treating the tail ends of low-concentration VOCs is generally applied by enterprises. The catalytic oxidation method is generally used at the tail end of the recovery method to treat the low-concentration VOCs waste gas which is difficult to treat by the VOCs recovery method.

The low-concentration VOCs are still relatively complex and generally comprise micromolecular alkane with low boiling point and difficult efficient oxidation, and meanwhile, hydrogen sulfide and part of organic sulfide which poison the catalyst are inevitably present in the tail gas components of the VOCs, so that the activity of the catalyst is reduced, the catalytic efficiency and the service life of the catalyst are influenced, and the final environment-friendly use effect of the device is influenced.

In the traditional process for catalytically oxidizing VOCs, the catalyst is singly filled, and the catalyst has a good effect when mainly used for efficiently treating VOCs such as large-molecular alkanes and high-boiling-point alkanes and alkenes, but the treatment efficiency is low when treating low-boiling-point small-molecular alkane compounds, so that the VOCs treatment efficiency of the whole device is influenced; in addition, if the VOCs contain a small amount of sulfide, the catalyst cannot be poisoned by the sulfide, but the adopted desulfurizer is expensive and sacrifices partial catalytic activity; if the front-end efficient desulfurization is adopted, the whole process of the device is complex, the flow is long, and the whole investment cost of the device is additionally increased.

Therefore, it is highly desirable to develop a catalyst grading method for catalytic oxidation of sulfur-containing VOCs, which is used for uniformly and efficiently treating VOCs with various boiling points, and simultaneously can efficiently protect the catalyst from poisoning by sulfides, and reduce the treatment cost of sulfur-containing VOCs.

Disclosure of Invention

The invention aims to overcome the defects of single catalyst layout, low efficiency of a sulfur-resistant catalyst in treating VOCs, high energy consumption and high investment cost in the prior art, and provides a catalyst grading method for catalytic oxidation of sulfur-containing VOCs.

It is a further object of the present invention to provide a process for the catalytic oxidation of sulfur-containing VOCs.

In order to achieve the above object, the present invention provides a catalyst grading method for catalytic oxidation of sulfur-containing VOCs, comprising the steps of:

passing a mixed reaction gas obtained by mixing sulfur-containing VOCs and oxygen-containing gas through n serial catalyst bed layers, wherein the n serial catalyst bed layers are a desulfurization bed layer and a first catalyst bed layer in sequence according to the contact sequence of the mixed reaction gas and the catalyst bed layers, and n is more than or equal to 3;

wherein, the filler of the desulfurization bed layer is a desulfurizer;

the nth-1 catalyst filled in the nth-1 catalyst bed layer is a noble metal catalyst;

the catalysts of the first catalyst bed layer to the (n-2) th catalyst bed layer are respectively and independently selected from at least one of honeycomb-shaped noble metal catalysts, granular noble metal catalysts, honeycomb-shaped transition metal oxide catalysts and granular transition metal oxide catalysts.

The invention also provides a method for catalytic oxidation of sulfur-containing VOCs, which comprises the following steps: under the condition of catalytic oxidation reaction, the mixed reaction gas obtained by mixing the sulfur-containing VOCs with the oxygen-containing gas passes through a catalyst bed layer and is subjected to contact reaction with a catalyst, and the catalyst bed layer is obtained by grading according to the method.

Through the technical scheme, the invention has the following technical effects:

1) according to the invention, the light hydrocarbons and heavy hydrocarbons in VOCs can be efficiently removed at a lower temperature (lower than 400 ℃) by using the cheap transition metal catalyst and the noble metal catalyst in a grading manner.

2) The invention avoids the use of sulfur-resistant catalyst and reduces the use cost of the catalyst.

Drawings

FIG. 1 is a schematic grading diagram of a reaction bed according to an embodiment of the present invention.

Description of the reference numerals

1 desulfurization bed layer desulfurizing agent 2 first bed layer catalyst

3 second bed catalyst 4 third bed catalyst

5 thermocouple

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In the present invention, the honeycomb noble metal catalyst refers to a honeycomb ceramic catalyst using noble metal as an active component, and the honeycomb transition metal oxide catalyst refers to a honeycomb ceramic catalyst using transition metal oxide as an active component.

In the invention, the catalyst bed layer filled with the granular catalyst is a granular catalyst bed layer; the catalyst bed layer filled with the honeycomb catalyst is a honeycomb catalyst bed layer.

The invention provides a catalyst grading method for catalytic oxidation of sulfur-containing VOCs, which comprises the following steps:

wherein, the filler of the desulfurization bed layer is a desulfurizer;

Preferably, the honeycomb-shaped noble metal catalyst is selected from a honeycomb-shaped platinum catalyst and/or a honeycomb-shaped palladium catalyst, and the Cpsi value of the honeycomb-shaped noble metal catalyst is 200-300.

Preferably, the particulate noble metal catalyst is a particulate platinum catalyst and/or a particulate palladium catalyst.

Preferably, the active component in the honeycomb-shaped transition metal oxide catalyst is preferably cobalt oxide. More preferably, the cobalt oxide compound is selected from cobalt oxide and/or cobaltosic oxide.

Preferably, the active ingredient in the particulate transition metal oxide catalyst is preferably cobalt oxide. More preferably, the cobalt oxide compound is selected from cobalt oxide and/or cobaltosic oxide.

In the invention, the section of a single hole of the honeycomb catalyst can be triangular, round, square, hexagonal or sinusoidal, or a pore channel structure with fins inside.

In the prior art, the catalytic oxidation temperature of VOCs is high (for example, the temperature of Pt catalytic oxidation light hydrocarbon is generally 500 ℃), and the invention uses the cheap transition metal catalyst and the noble metal catalyst in a grading way, so that light hydrocarbon and heavy hydrocarbon can be effectively removed at a lower temperature (lower than 400 ℃), layered and efficient removal of multi-component VOCs materials is realized, and the treatment cost of VOCs is reduced.

In the invention, the main function of the desulfurization bed layer is to absorb and convert hydrogen sulfide and organic sulfide under the condition of medium temperature, and in the contact reaction carried out on the desulfurization bed layer, the space velocity of the contact reaction is 2000-5000 h^-1Preferably 2500-3000 h^-1The contact reaction temperature is 200-400 ℃, preferably 310-350 ℃, and at the moment, the reaction equation is as follows:

MO+H₂S→MS+H₂o, and releasing certain heat;

COS+MO→CO₂+ MS, and release certain heat;

CS₂+2MO→2MS+CO₂and releases a certain amount of heat; wherein M is at least one selected from zinc, iron and manganese.

In the invention, because the temperature of the gas at the inlet of the catalytic oxidation device is generally between 200 and 400 ℃, and the desulfurizer has the highest reaction activity at the temperature, the temperature of the VOCs can be directly utilized to participate in the reaction without additional heating.

The desulfurization capacity of the desulfurization bed layer is large, the removal efficiency of sulfur is high, and the desulfurization bed layer can be used for fine desulfurization. The honeycomb ceramic desulfurizer is beneficial to reducing the overall pressure drop of a catalytic bed and protecting other bed catalysts, and under the preferable condition, the desulfurizer is a honeycomb desulfurizer taking transition metal oxide as an active component, and the Cpsi value of the desulfurizer is 200-300; further preferably, the transition metal oxide is at least one selected from the group consisting of zinc oxide, iron oxide, manganese oxide, and ferrous oxide, and more preferably zinc oxide.

Different Cpsi values help to achieve a secondary distribution and transfer of gas in the radial direction, helping to achieve different opportunities for contact of the VOCs with the catalyst.

In the invention, the first catalyst bed layer to the n-2 catalyst bed layer are mainly used for catalyzing and oxidizing VOCs, and in order to improve the efficiency of sulfur-containing VOCs, the number of the catalyst bed layers and the specific catalyst types in each catalyst bed layer can be flexibly changed according to the types and the contents of organic matters in VOCs to be treated actually. For example, the honeycomb-shaped transition metal oxide catalyst can catalyze and oxidize small-molecule organic matters in the VOCs, and when the VOCs contain small-molecule organic matters such as ethane and propane, a catalyst bed layer filled with the honeycomb-shaped transition metal oxide catalyst is arranged in the catalyst bed layer; at this time, the reaction equation of the contact reaction performed in the catalyst bed is: VOCs (small molecule) + O₂→CO₂+H₂O, and releasing certain heat; the space velocity of the contact reaction is 5000-12000 h^-1Preferably 8000-10000 h^-1The contact temperature of the reaction is 220-350 ℃, and preferably 260-310 ℃.

The honeycomb noble metal catalyst can catalyze and oxidize macromolecular hydrocarbons in VOCs (volatile organic compounds), and when the VOCs contain C₅～C₁₀When the (alkane or arene) macromolecular organic matter is contained, the catalyst bed layer contains a catalyst bed layer filled with a honeycomb-shaped noble metal catalyst; at this time, the reaction equation of the contact reaction performed in the catalyst bed is: VOCs (macromolecules) + O₂→CO₂+H₂O, and releasing certain heat; the space velocity of the contact reaction is 12000-20000 h^-1Preferably 15000 to 18000h^-1The contact temperature of the reaction is 200-550 ℃, and preferably 310-350 ℃.

The n-1 th catalyst bed layer is mainly used for further processing the previous n-And 2, treating the residual small amount of VOCs in the layer 2, thereby further reducing the types and the content of organic matters at the discharge port and improving the treatment efficiency of the VOCs. In the contact reaction carried out on the n-2 catalyst bed layer, the space velocity of the reaction is 2000-12000 h^-1(ii) a The reaction temperature is 200-550 ℃; the equation for the reaction carried out in this bed is: VOCs (minor amount remaining) + O₂→CO₂+H₂O, and releases a certain amount of heat.

The honeycomb catalyst has dense pore channels and can fully contact with VOCs, but has larger resistance, and the granular catalyst has high specific surface area and larger contact area with VOCs. Therefore, by adopting the catalyst bed layers with different cpsi values and the granular catalyst bed layers to be matched for use, an effective pore channel mismatching design is formed between the different catalyst bed layers, so that turbulence is favorably formed, the probability of combining the VOCs molecules with the catalyst is increased, the effective collision times are increased, the apparent activation energy of a catalytic oxidation system is reduced, the actual treatment efficiency of the catalyst for treating the VOCs is obviously improved, and the short-circuit risk of VOCs gas is reduced. In a preferred embodiment of the present invention, the first to n-2 catalyst beds, the particulate catalyst beds and the honeycomb catalyst beds are alternately arranged, and for example, the catalysts of the first to n-2 catalyst beds may be particulate catalysts, honeycomb transition metal oxide catalysts, particulate catalysts … noble metal catalysts in sequence. To promote the formation of turbulent gas streams of VOCs in the catalyst bed, the particulate catalyst bed may preferably be disposed between two honeycomb catalyst beds.

In a preferred embodiment of the present invention, when the VOCs contain benzene compounds (such as toluene, benzene, xylene, etc.), the catalyst bed layer contains a catalyst bed layer filled with a honeycomb-shaped noble metal catalyst and a catalyst bed layer filled with a granular noble metal catalyst, and the volume ratio of the honeycomb-shaped noble metal catalyst to the granular noble metal catalyst is 5-10: 1.

In the invention, the number of the catalyst beds can be adjusted according to the specific types of VOCs in sulfur-containing VOCs to be actually treated, and according to the grading method disclosed by the invention, 2-4 catalyst beds can be adopted to play a higher catalytic oxidation role (more than 98%) on VOCs, so that n is more than or equal to 3 and less than or equal to 5 in the invention, namely the value of n is 3, 4 or 5.

Fig. 1 is a schematic view of the gradation of a reaction bed according to an embodiment of the present invention, as shown in fig. 1, and in a preferred embodiment of the present invention, the number of catalyst beds is 4, and the catalyst gradation method for the catalytic oxidation of sulfur-containing VOCs includes the steps of:

enabling mixed reaction gas obtained after mixing sulfur-containing VOCs and oxygen-containing gas to pass through four catalyst beds connected in series to perform contact reaction with a catalyst under the condition of catalytic oxidation reaction, wherein the four catalyst beds connected in series sequentially comprise a desulfurization bed, a first catalyst bed, a second catalyst bed and a third catalyst bed according to the contact sequence of the mixed reaction gas;

the desulfurizer filled in the desulfurization bed layer is a honeycomb desulfurizer which takes transition metal oxide as an active component;

the first catalyst filled in the first catalyst bed layer is a honeycomb-shaped transition metal oxide catalyst or a honeycomb-shaped noble metal catalyst;

the second catalyst filled in the second catalyst bed layer is a honeycomb-shaped transition metal oxide catalyst or a honeycomb-shaped noble metal catalyst;

the third catalyst filled in the third catalyst bed layer is a granular noble metal catalyst; and the first catalyst is different from the second catalyst.

In another preferred embodiment of the present invention, the first catalyst is a honeycomb ceramic catalyst with platinum as an active component, and the Cpsi value of the first catalyst is 200 to 300; in the contact reaction carried out by the first catalyst bed layer, the space velocity of the reaction is 12000-20000 h^-1Preferably 15000 to 18000h^-1The reaction temperature is 200-550 ℃, preferably 310-350 ℃. The second catalyst is a honeycomb ceramic catalyst taking a cobalt oxide compound as an active component, the Cpsi value of the second catalyst is 300-400, and the second catalyst enters the second catalyst bed layerIn the row contact reaction, the space velocity of the reaction is 5000-12000 h^-1Preferably 8000-10000 h^-1The reaction temperature is 220-350 ℃, and preferably 260-310 ℃.

In another preferred embodiment of the present invention, the first catalyst is a honeycomb ceramic catalyst having a cobalt oxide compound as an active component, and has a Cpsi value of 300 to 400; in the contact reaction carried out on the first catalyst bed layer, the space velocity of the reaction is 5000-12000 h^-1Preferably 8000-10000 h^-1The reaction temperature is 220-350 ℃, and preferably 260-310 ℃; the second catalyst is a honeycomb ceramic catalyst taking platinum as an active component, the Cpsi value of the second catalyst is 200-300, and the space velocity of the reaction in the contact reaction carried out on the second catalyst bed layer is 12000-20000 h^-1Preferably 15000 to 18000h^-1The reaction temperature is 200-550 ℃, preferably 310-350 ℃.

In a preferred embodiment of the present invention, the third catalyst is particulate platinum and/or particulate palladium. The particulate catalyst is used to further treat the small amount of VOCs material remaining in the first three layers, thereby further reducing the concentration of organic contaminants in the catalytic oxidation exhaust outlet. Under the preferable condition, in the contact reaction carried out on the third catalyst bed layer, the space velocity of the reaction is 2000-12000 h^-1(ii) a The reaction temperature is 200-550 ℃; the equation for the reaction carried out in this bed is: VOCs (minor amount remaining) + O₂→CO₂+H₂O, and releases a certain amount of heat.

In this embodiment, the process for treating sulfur-containing VOCs is: firstly, sulfur-containing VOCs are heated to 260-300 ℃ when passing through an inlet of a catalytic oxidation device, then directly enter a desulfurization bed layer, and various sulfides (such as hydrogen sulfide and the like) are trapped through the reaction of the desulfurization bed layer; then the VOCs sequentially enter the first catalyst bed layer to the third catalyst bed layer, and under the high-efficiency action of the first catalyst and the second catalyst, molecules C3 and below and macromolecules C4 and above in the VOCs are all converted into carbon dioxide and water vapor, and heat is released; then, a small amount of VOCs which are not subjected to purification reaction due to short circuit and the like are trapped in the third catalyst bed layer, and are catalyzed and oxidized into carbon dioxide and water vapor by the third catalyst.

In another preferred embodiment of the present invention, the number of the catalyst beds is 5, and the catalyst grading method for catalytic oxidation of sulfur-containing VOCs comprises the following steps:

enabling a mixed reaction gas obtained after mixing sulfur-containing VOCs and oxygen-containing gas to pass through five catalyst beds connected in series to perform contact reaction with a catalyst under a catalytic oxidation reaction condition, wherein the five catalyst beds connected in series sequentially comprise a desulfurization bed, a first catalyst bed, a second catalyst bed, a third catalyst bed and a fourth catalyst bed according to the contact sequence of the mixed reaction gas;

the filler of the desulfurization bed layer is a honeycomb desulfurizer which takes transition metal oxide as an active component, and at the moment, in the contact reaction of the desulfurization bed layer, the space velocity of the reaction is 2000-5000 h^-1Preferably 2500-3000 h^-1(ii) a The reaction temperature is 200-400 ℃, and preferably 310-350 ℃;

the first catalyst filled in the first catalyst bed layer is a granular transition metal oxide catalyst, and at the moment, in the contact reaction carried out on the catalyst bed layer, the space velocity of the contact reaction is 2000-12000 h^-1Preferably 5000 to 8000h^-1(ii) a The temperature of the contact reaction is 200-550 ℃, and preferably 310-350 ℃;

the second catalyst filled in the second catalyst bed layer is a honeycomb-shaped transition metal oxide catalyst, the Cpsi value of the second catalyst is 300-400, and the space velocity of the contact reaction in the contact reaction carried out on the catalyst bed layer is 5000-12000 h^-1Preferably 8000-10000 h^-1(ii) a The temperature of the contact reaction is 220-350 ℃, preferably 260-310 ℃;

the third catalyst filled in the third catalyst bed layer is a granular noble metal catalyst, and at the moment, in the contact reaction carried out on the catalyst bed layer, the space velocity of the contact reaction is 2000-12000 h^-1Preferably 5000 to 8000h^-1(ii) a The temperature of the contact reaction is 200-550 ℃, and preferably 310-350 ℃;

the fourth catalyst filled in the fourth catalyst bed layer is a honeycomb-shaped noble metal catalyst, the Cpsi value of the honeycomb-shaped noble metal catalyst is 200-300, and the space velocity of the contact reaction in the contact reaction carried out on the catalyst bed layer is 12000-20000 h^-1Preferably 15000 to 18000h^-1(ii) a The temperature of the contact reaction is 200-550 ℃, and preferably 310-350 ℃.

In another preferred embodiment of the present invention, the honeycomb ceramic catalyst in the desulfurization bed, the first catalyst bed and the second catalyst bed can be laid in a round or square catalyst bed, so as to avoid gas short circuit between the block catalyst and the catalyst.

The present invention also provides a process for the catalytic oxidation of sulfur-containing VOCs, the process comprising: under the condition of catalytic oxidation reaction, the mixed reaction gas obtained by mixing the sulfur-containing VOCs with the oxygen-containing gas passes through a catalyst bed layer and is subjected to contact reaction with a catalyst, wherein the catalyst bed layer is obtained by grading according to the method.

Under the optimized condition, the volume fraction of VOCs in the mixed reaction gas is less than or equal to 25 percent LEL; the volume fraction of oxygen in the mixed reaction gas is 1-3%.

In addition, the gas flow direction of the mixed reaction gas can sequentially pass through each bed catalyst from bottom to top or from top to bottom, and the inlet and the outlet of each bed catalyst can be provided with a thermocouple sensor, so that the actual reaction condition of each bed can be effectively monitored.

The present invention will be described in detail below with reference to examples.

In the following examples, the desulfurizing agent is a honeycomb desulfurizing agent containing ZnO as a main active component, which is obtained from desulfurizing agent filler corporation of Pingxiang city, and has a CPSI value of 300; the honeycomb ceramic catalyst with Co as the main active component is purchased from Kelain, the model is Envicat-2546, and the CPSi is 400; the honeycomb ceramic catalyst taking Pt as a main active component is purchased from Kelain, the model is Envicat-2580, and the CPSi is 300.

Example 1

wherein the desulfurizer filled in the desulfurization bed layer is a honeycomb desulfurizer (Cpsi value is 300) taking ZnO as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 3000h^-1The reaction temperature is 310 ℃;

the first catalyst filled in the first catalyst bed layer is granular Co₂O₃The catalyst is subjected to the contact reaction in the bed layer under the condition that the space velocity of the reaction is 6000h^-1The reaction temperature is 320 ℃;

the second catalyst filled in the second catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 400) taking Co as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 8000h^-1The reaction temperature is 310 ℃;

the third catalyst filled in the third catalyst bed layer is granular Pt, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 6000h^-1The reaction temperature is 320 ℃;

the fourth catalyst filled in the fourth catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 300) taking Pt as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 18000h^-1The reaction temperature is 310 ℃;

the fifth catalyst filled in the fifth catalyst bed layer is granular Pt, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 2000h^-1The reaction temperature was 310 ℃.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 1.

TABLE 1

As can be seen from Table 1, the method provided by the present example has an alkane treatment efficiency as high as 99.99%.

Example 2

Enabling mixed reaction gas obtained by mixing sulfur-containing VOCs with oxygen-containing gas (the volume fraction of oxygen is 2%) to pass through four catalyst beds connected in series, and enabling the mixed reaction gas to be in contact reaction with a catalyst under the condition of catalytic oxidation reaction, wherein the four catalyst beds connected in series are a desulfurization bed, a first catalyst bed, a second catalyst bed and a third catalyst bed in sequence according to the contact sequence of the four catalyst beds connected in series with a mixed reactor;

the first catalyst filled in the first catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 300) taking Pt as a main active component, and the contact reaction condition carried out on the first catalyst bed layer is that the space velocity of the reaction is 18000h^-1The reaction temperature is 310 ℃;

the third catalyst filled in the third catalyst bed layer is a granular Pt catalyst, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 2000h^-1The reaction temperature was 310 ℃.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 2.

TABLE 2

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0.1ppm	99.9％
COS	50ppm	0.1ppm	99.8％
				CS₂	50ppm	0.01ppm	99.9％
Benzene and its derivatives	2000mg/m³	＜0.1mg/m³	≥99.99％
				Xylene	2000mg/m³	＜0.1mg/m³	≥99.99％
Ethane (III)	500mg/m³	＜1mg/m³	≥99.8％
				Propane	1000mg/m³	＜1mg/m³	≥99.9％
Ethylene	500mg/m³	＜1mg/m³	≥99.8％

As can be seen from table 2, the comprehensive treatment efficiency of the method provided in this example on sulfur-containing VOCs reaches more than 99.8%.

Example 3

Enabling mixed reaction gas obtained after mixing sulfur-containing VOCs and oxygen-containing gas to pass through four catalyst beds connected in series to perform contact reaction with a catalyst under the condition of catalytic oxidation reaction, wherein the four catalyst beds connected in series are a first catalyst bed, a second catalyst bed, a third catalyst bed and a fourth catalyst bed in sequence according to the contact sequence of the mixed reaction vessel;

wherein the desulfurizer filled in the desulfurization bed layer is a honeycomb desulfurizer (Cpsi value is 300) taking ZnO as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 2500h^-1The reaction temperature is 350 ℃;

the first catalyst filled in the first catalyst bed layer is mainly CoThe honeycomb ceramic catalyst (Cpsi value is 400) of active component is used for carrying out the contact reaction in the bed layer under the condition that the space velocity of the reaction is 8000h^-1The reaction temperature is 350 ℃;

the second catalyst filled in the second catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 300) taking precious metal Pt as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 15000h^-1The reaction temperature is 350 ℃;

the third catalyst filled in the third catalyst bed layer is a granular Pt catalyst, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 2000h^-1The reaction temperature was 350 ℃.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 3.

TABLE 3

As can be seen from Table 3, at higher reaction temperature, the outlet indexes of the concentration of sulfide at the outlet of the bed layer and the concentration of VOCs of other components are lower, and the reaction efficiency is higher.

Example 4

wherein the desulfurizer filled in the desulfurization bed layer is spherical granular ZnO, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 2000h^-1The reaction temperature is 310 ℃;

the first catalyst filled in the first catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 300) taking noble metal Pt as a main active component, and the contact reaction condition carried out on the first catalyst bed layer is that the space velocity of the reaction is 20000h^-1The reaction temperature is 310 ℃;

the second catalyst filled in the second catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 400) taking Co as a main active component, and the contact reaction condition carried out on the bed layer is that the space velocity of the reaction is 12000h^-1The reaction temperature is 310 ℃;

Under the action of the granular medium-temperature desulfurizer, the contact area between sulfur-containing VOCs and the desulfurizer is larger, the contact chance is more, and the effect of removing sulfides is better.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 4.

TABLE 4

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0ppm	100％
COS	50ppm	0ppm	100％
				CS₂	50ppm	0ppm	100％
Benzene and its derivatives	2000mg/m³	＜0.01mg/m³	≥99.99％
				Xylene	2000mg/m³	＜0.01mg/m³	≥99.99％
Ethane (III)	500mg/m³	＜0.1mg/m³	≥99.9％
				Propane	1000mg/m³	＜0.1mg/m³	≥99.9％
Ethylene	500mg/m³	＜0.1mg/m³	≥99.9％

Example 5

wherein the desulfurizer filled in the desulfurization bed layer is spherical granular Fe₃O₄The contact reaction condition in the bed layer is that the space velocity of the reaction is 5000h^-1The reaction temperature is 310 ℃;

the first catalyst filled in the first catalyst bed layer is a honeycomb ceramic catalyst (Cpsi value is 300) taking precious metal Pt as a main active component, the section of a pore channel of the honeycomb ceramic catalyst is square, and the contact reaction condition carried out on the first catalyst bed layer is that the space velocity of the reaction is 12000h^-1The reaction temperature is 3100 ℃;

the second catalyst filled in the second catalyst bed layer is a honeycomb metal-based catalyst (Cpsi value is 400) taking Co as a main active component, the cross section of a pore channel of the second catalyst bed layer is triangular, and the contact reaction condition carried out on the second catalyst bed layer is that the space velocity of the reaction is 5000h^-1The reaction temperature is 310 ℃;

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 5.

TABLE 5

The desulfurization performance of the ferric oxide is slightly poorer than that of the zinc oxide, so that the outlet index of sulfide is increased, and meanwhile, the removal effect of other VOCs of other catalytic beds can be reduced after the concentration of the sulfide is increased, so that the reaction efficiency is reduced.

Example 6

The process of example 2 was followed except that the first catalyst bed was not included, i.e., the honeycomb ceramic catalyst with Pt as the main active component was not included, and in this case, the reaction bed was mainly used for sulfur-containing multicomponent VOCs having a (C2-C3) small molecule content of < 1000mg/m³The content of macromolecules such as C4-C10 is 1000mg/m³～6000mg/m³And the total concentration of sulfide is between 50ppm and 2000 ppm.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 6.

TABLE 6

From example 6, it can be seen that in the absence of the light hydrocarbon elimination layer (first catalyst bed), the sulfide concentration and the concentrations of macromolecular benzene and xylene at the outlet of the device are substantially the same as those in example 2 under the same conditions as those in the other reaction conditions of example 2. Light hydrocarbon small molecule ethane, propane, ethylene and the like show different treatment efficiencies, and the treatment efficiency is obviously lower than that of the example 2.

Example 7

The process of example 6 was followed except that the VOCs contained no benzene and benzene series.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 7.

TABLE 7

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0.1ppm	99.9％
COS	50ppm	0.1ppm	99.8％
				CS₂	50ppm	0.01ppm	99.9％
Ethane (III)	500mg/m³	＜1mg/m³	≥99.8％
				Propane	1000mg/m³	＜1mg/m³	≥99.9％
Ethylene	500mg/m³	＜1mg/m³	≥99.8％

Example 8

The method of example 2 was followed except that the second catalyst bed was not included, i.e., the honeycomb ceramic catalyst with Co as the main active component was not included, and in this case, the reaction bed was mainly used for sulfur-containing multicomponent VOCs containing (C2-C3) small molecules in an amount of < 1000mg/m³The content of macromolecules such as C4-C10 is 1000mg/m³～6000mg/m³And the total concentration of sulfide is between 50ppm and 2000 ppm.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 8.

TABLE 8

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0.1ppm	99.9％
COS	50ppm	0.1ppm	99.8％
				CS₂	50ppm	0.01ppm	99.9％
Benzene and its derivatives	2000mg/m³	＜2mg/m³	≥99.9％
				Xylene	2000mg/m³	＜2mg/m³	≥99.9％
Ethane (III)	500mg/m³	＜1mg/m³	≥99.8％
				Propane	1000mg/m³	＜1mg/m³	≥99.9％
Ethylene	500mg/m³	＜1mg/m³	≥99.8％

From example 8, it can be seen that in the absence of the second catalyst bed, under the same conditions as those in the other reaction conditions of example 2, the sulfide concentration and light hydrocarbon small molecules at the outlet of the device are substantially the same as those in example 2. Benzene, xylene, etc. showed different treatment efficiencies, and the treatment efficiency was less than that of example 2.

Example 9

The process of example 8 was followed except that the VOCs did not contain light hydrocarbons (ethane, ethylene and propane).

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 9.

TABLE 9

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0.1ppm	99.9％
COS	50ppm	0.1ppm	99.8％
				CS₂	50ppm	0.01ppm	99.9％
Benzene and its derivatives	2000mg/m³	＜2mg/m³	≥99.9％
				Xylene	2000mg/m³	＜2mg/m³	≥99.9％

Comparative example 1

The process of example 2 is followed except that the desulfurization bed is not included, in which case the reaction bed is used primarily for sulfur-containing multicomponent VOCs having a content of macromolecules of (C4-C10) and above of < 1000mg/m³The content of light hydrocarbon molecules such as C2-C3 and the like is 1000mg/m³～6000mg/m³And the total sulfide concentration is between 50ppm and 2000 ppm.

In this comparative example, the initial concentrations of the respective substances in the sulfur-containing VOCs and the treatment effects are shown in table 10.

Watch 10

As can be seen from the comparative example 1, under the action of the lack of the first-stage high-temperature desulfurizing agent, the removal efficiency of hydrogen sulfide, carbonyl sulfide and carbon disulfide sulfide is low, most of the hydrogen sulfide, carbonyl sulfide and carbon disulfide sulfide are converted into other sulfides and are fixed on the catalyst, the catalyst efficiency of other beds is reduced, and finally the catalyst is deactivated, so that the treatment efficiency of other VOCs is also influenced.

Comparative example 2

The process of example 2 was followed except that the fourth bed catalyst was not included, in which case the reaction bed was primarily used with sulfur-containing multicomponent VOCs having a (C2-C3) small molecule content of < 1000mg/m³The content of macromolecules such as C4-C10 is 1000mg/m³～6000mg/m³And the total concentration of sulfide is between 50ppm and 2000 ppm.

In this example, the initial concentrations of the various substances in the sulfur-containing VOCs and the treatment effect are shown in table 11.

TABLE 11

Volume content	Untreated sulfur-containing VOCs	Treated gas	Efficiency of treatment
				H₂S	100ppm	0.1ppm	99.9％
COS	50ppm	0.1ppm	99.8％
				CS₂	50ppm	0.01ppm	99.9％
Benzene and its derivatives	2000mg/m³	＜4mg/m³	≥99.8％
				Xylene	2000mg/m³	＜4mg/m³	≥99.8％
Ethane (III)	500mg/m³	＜5mg/m³	≥99.5％
				Propane	1000mg/m³	＜5mg/m³	≥99.5％
Ethylene	500mg/m3	＜3mg/m3	≥99.4％

It can be seen from comparative example 2 that in the absence of the fourth layer, the outlet concentrations of light hydrocarbon, including light hydrocarbon, small-molecule ethane, propane and propylene, and aromatic hydrocarbons, benzene and xylene, were slightly increased and the treatment efficiency was slightly decreased under the same conditions as those in the other reaction conditions of example 2. The main reason is that there are still "short circuits" in the grading process, resulting in small numbers of VOCs molecules not in sufficient contact with the catalyst surface.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A catalyst grading method for catalytic oxidation of sulfur-containing VOCs is characterized by comprising the following steps,

wherein, the filler of the desulfurization bed layer is a desulfurizer;

2. The catalyst staging method for the catalytic oxidation of sulfur-containing VOCs according to claim 1, wherein the catalyst bed packed with a granular catalyst is a granular catalyst bed and the catalyst bed packed with a honeycomb catalyst is a honeycomb catalyst bed;

wherein, in the first catalyst bed layer to the n-2 catalyst bed layer, the granular catalyst bed layer and the honeycomb catalyst bed layer are alternately arranged;

preferably, the particulate catalyst bed is disposed between two honeycomb catalyst beds.

3. The catalyst grading process for the catalytic oxidation of sulfur-containing VOCs according to claim 1 or 2, wherein the desulfurizing agent is a particulate transition metal oxide or a honeycomb desulfurizing agent having a transition metal oxide as an active component;

preferably, the desulfurizer is a honeycomb desulfurizer, and the Cpsi value is 200-300;

preferably, the desulfurizing agent is at least one selected from zinc oxide, iron oxide, manganese oxide and ferrous oxide;

preferably, the catalyst of the n-1 th catalyst bed layer is metal platinum and/or metal palladium.

4. The catalyst staging method of claim 3, wherein the sulfur-containing VOCs contain C₄When the small molecular organic matters are the following, the catalyst bed layer contains a catalyst bed layer filled with a honeycomb-shaped transition metal oxide catalyst; and/or

When the sulfur-containing VOCs contain C₅～C₁₀When the macromolecular organic matter is contained, the catalyst bed layer contains a catalyst bed layer filled with a honeycomb-shaped noble metal catalyst;

preferably, the Cpsi value of the honeycomb transition metal oxide catalyst is 300-400;

preferably, the Cpsi value of the honeycomb-shaped noble metal catalyst is 200-300.

5. The catalyst staging method for the catalytic oxidation of sulfur-containing VOCs according to claim 4, wherein, when the sulfur-containing VOCs contain benzene compounds, the catalyst bed contains a catalyst bed packed with a honeycomb-shaped noble metal catalyst and a catalyst bed packed with a particulate noble metal catalyst;

preferably, the volume ratio of the honeycomb-shaped noble metal catalyst to the granular noble metal catalyst is 5-10: 1.

6. The catalyst staging method for the catalytic oxidation of sulfur-containing VOCs according to any one of claims 1 to 5, wherein the catalyst bed comprises four catalyst beds in series, which are, in order, a desulfurization bed, a first catalyst bed, a second catalyst bed, and a third catalyst bed;

the desulfurizer of the desulfurization bed filler is a honeycomb desulfurizer which takes transition metal oxide as an active component;

the third catalyst filled in the third catalyst bed layer is a granular noble metal catalyst;

and the first catalyst is different from the second catalyst.

7. The catalyst grading process for the catalytic oxidation of sulfur-containing VOCs according to claim 6, wherein the first catalyst is a honeycomb precious metal catalyst having a Cpsi value of 200 to 300;

the second catalyst is a honeycomb transition metal oxide catalyst, and the Cpsi value of the second catalyst is 300-400.

8. The catalyst grading process for the catalytic oxidation of sulfur-containing VOCs according to claim 6, wherein the first catalyst is a honeycomb transition metal oxide catalyst having a Cpsi value of 300 to 400;

the second catalyst is a honeycomb-shaped noble metal catalyst, and the Cpsi value of the second catalyst is 200-300.

9. The catalyst staging method for the catalytic oxidation of sulfur-containing VOCs according to any one of claims 1 to 5, wherein the catalyst bed comprises five catalyst beds in series, which are, in order, a desulfurization bed, a first catalyst bed, a second catalyst bed, a third catalyst bed, and a fourth catalyst bed;

the first catalyst filled in the first catalyst bed layer is a granular transition metal oxide catalyst;

the second catalyst filled in the second catalyst bed layer is a honeycomb-shaped transition metal oxide catalyst, and the Cpsi value of the second catalyst is 300-400;

the fourth catalyst filled in the fourth catalyst bed layer is a honeycomb-shaped precious metal catalyst, and the Cpsi value of the honeycomb-shaped precious metal catalyst is 200-300.

10. A process for the catalytic oxidation of sulfur-containing VOCs, the process comprising: under the condition of catalytic oxidation reaction, the mixed reaction gas obtained by mixing sulfur-containing VOCs and oxygen-containing gas passes through a catalyst bed layer to carry out contact reaction with a catalyst, and is characterized in that the catalyst bed layer is obtained by grading according to the method of any one of claims 1 to 9.

11. The method as claimed in claim 10, wherein in the contact reaction carried out in the desulfurization bed layer, the space velocity of the contact reaction is 2000-5000 h^-1The contact reaction temperature is 200-400 ℃;

preferably, the space velocity of the contact reaction is 2500-3000 h^-1The contact reaction temperature is 310-350 ℃.

12. A process according to claim 10 or 11, wherein the catalyst is in the catalyst bedWhen the catalyst bed layer filled with the honeycomb-shaped noble metal catalyst is contained, in the contact reaction carried out on the catalyst bed layer, the space velocity of the contact reaction is 12000-20000 h^-1The temperature of the contact reaction is 200-550 ℃;

preferably, the space velocity of the contact reaction is 15000-18000 h^-1And the temperature of the contact reaction is 310-350 ℃.

13. The method according to claim 10 or 12, wherein when the catalyst bed comprises a catalyst bed packed with a particulate noble metal catalyst, the space velocity of the contact reaction in the contact reaction carried out in the catalyst bed is 2000 to 12000h^-1The temperature of the contact reaction is 200-550 ℃;

preferably, the space velocity of the contact reaction is 5000-8000 h^-1And the temperature of the contact reaction is 310-350 ℃.

14. The method according to claim 10 or 13, wherein when the catalyst bed comprises a catalyst bed filled with honeycomb-shaped transition metal oxide catalyst, the space velocity of the contact reaction in the contact reaction carried out in the catalyst bed is 5000-12000 h^-1The temperature of the contact reaction is 220-350 ℃;

preferably, the space velocity of the contact reaction is 8000-10000 h^-1And the temperature of the contact reaction is 260-310 ℃.

15. The method according to claim 10 or 14, wherein when the catalyst bed comprises a catalyst bed packed with a particulate transition metal oxide catalyst, the space velocity of the contact reaction in the contact reaction carried out in the catalyst bed is 2000 to 12000h^-1The temperature of the contact reaction is 200-550 ℃;

16. The method according to claims 11-15, wherein the volume fraction of VOCs in the mixed reactant gas is ≤ 25% LEL; and/or

The volume fraction of oxygen in the mixed reaction gas is 1-3%.