阅读说明：本技术 一种催化氧化VOCs催化剂的在线活化方法 (Online activation method of catalyst for catalytic oxidation of VOCs ) 是由 赖庆智 敬丹丹 龙志 颜翔 于 2019-09-19 设计创作，主要内容包括：本发明公开了一种催化氧化VOCs催化剂的在线活化方法,包括如下步骤：吹扫：利用温度200～300℃的热空气对失活催化剂吹扫2～3h,清除吸附在催化剂上的油污和粉尘；喷淋：吹扫完成后,待催化剂自然降温至常温,以15～60mL/min的速度向催化剂上喷淋活化补充液,喷淋量为催化剂载体重量的30％～60％,静置过夜,待喷淋的活性组分充分渗透进入催化剂孔洞及其内部；煅烧：利用温度200～300℃的热空气,在空速3000～7000h<Sup>-1</Sup>的条件下对喷淋活化补充液的催化剂煅烧1～5h,完成失活催化剂的在线活化。本发明的催化氧化VOCs催化剂的在线活化方法,活化后的催化剂性能可恢复到催化剂新品性能的90％以上,可延长催化剂的使用寿命1～1.5年,催化剂耗损量减少,催化剂运行成本降低1/3～1/2。(The invention discloses an online activation method of a catalyst for catalytic oxidation of VOCs, which comprises the following steps: purging: blowing the deactivated catalyst for 2-3 h by using hot air at the temperature of 200-300 ℃, and removing oil stains and dust adsorbed on the catalyst; spraying: after purging is finished, after the catalyst is naturally cooled to normal temperature, spraying an activation supplementing liquid onto the catalyst at a speed of 15-60 mL/min, wherein the spraying amount is 30-60% of the weight of the catalyst carrier, standing overnight, and fully spraying active componentsPermeating into pores and the inside of the catalyst; and (3) calcining: hot air with the temperature of 200-300 ℃ is utilized, and the air speed is 3000-7000 h ‑1 Calcining the catalyst sprayed with the activation replenishing liquid for 1-5 h under the condition of (1) to complete the online activation of the deactivated catalyst. According to the on-line activation method of the catalyst for catalytic oxidation of VOCs, the performance of the activated catalyst can be recovered to more than 90% of the new performance of the catalyst, the service life of the catalyst can be prolonged by 1-1.5 years, the loss of the catalyst is reduced, and the operation cost of the catalyst is reduced by 1/3-1/2.)

1. An on-line activation method of a catalyst for catalytic oxidation of VOCs is characterized in that: the method comprises the following steps:

purging: blowing the deactivated catalyst for 2-3 h by using hot air at the temperature of 200-300 ℃, and removing oil stains and dust adsorbed on the catalyst;

Spraying: after purging is finished, after the catalyst is naturally cooled to normal temperature, spraying an activation supplementing liquid onto the catalyst at a speed of 15-60 mL/min, wherein the spraying amount is 30-60% of the weight of the catalyst carrier, standing overnight, and fully permeating the active components to be sprayed into the holes of the catalyst and the interior of the holes;

And (3) calcining: hot air with the temperature of 200-300 ℃ is utilized, and the air speed is 3000-7000 h^-1Calcining the catalyst sprayed with the activation replenishing liquid for 1-5 h under the condition of (1) to complete the online activation of the deactivated catalyst.

2. The method of claim 1, wherein the catalyst further comprises: further comprising drying: before the catalyst sprayed with the activating supplementary liquid is calcined, hot air at the temperature of 60-120 ℃ is utilized, and the space velocity is 5000-10000 h^-1Under the conditions ofAnd drying the catalyst sprayed with the activating supplementary liquid for 1-5 h.

3. The method of claim 2, wherein the catalyst further comprises: the spraying, drying and calcining are repeated at least once.

4. The method of claim 1, wherein the catalyst further comprises: in the purging step, when carbon deposition exists in the deactivated catalyst, the temperature of hot air needs to be raised to 300-450 ℃ so as to relieve or eliminate the carbon deposition.

5. The method of claim 1, wherein the catalyst further comprises: the hot air is obtained by heating air by utilizing a preheating and heating system matched with the deactivated catalyst.

6. the method of claim 1, wherein the catalyst further comprises: the activation replenishing liquid comprises 40-80 wt% of an active component precursor, wherein the active component precursor is at least one nitrate of silver, platinum, palladium, manganese, cobalt, cerium, nickel and copper.

7. The method of claim 6, wherein the catalyst further comprises: the active components of the activation make-up solution comprise active components of the deactivated catalyst.

8. The method of claim 6, wherein the catalyst further comprises: the activation make-up fluid does not comprise an active component of the deactivated catalyst, but is a new active component which is introduced for improving the performance of the catalyst and is not possessed by the deactivated catalyst, and the content of the new active component in the activation make-up fluid is 0.1-15 wt%.

9. The method of claim 1, wherein the catalyst further comprises: the activation replenishing liquid realizes the in-situ spraying of the deactivated catalyst through a spraying circulation system matched with the deactivated catalyst or manual direct spraying, and the deactivated catalyst does not need to be moved away from the catalytic reactor.

Technical Field

The invention relates to the technical field of VOCs catalysts, in particular to an online activation method of a catalyst for catalytic oxidation of VOCs.

Background

The natural source of the emission of Volatile Organic Compounds (VOCs) is far higher than the artificial source in the global range, but the artificial source of the emission of the VOCs in some industrial intensive areas in China is far higher than the natural source. In recent years, the total amount of VOCs discharged in China rises year by year. Chenying and the like adopt an emission factor method to estimate that the emission amount of VOCs in the industry of China in 09 years is about 1200 ten thousand tons, and the total amount of VOCs emitted in China in years is far more than 2000 ten thousand tons according to the average annual growth rate of 11.5 percent. VOCs discharges a lot and harm greatly, not only directly endangers human health, still can take place photochemical reaction with nitrogen oxide under certain meteorological condition, arouses ozone concentration in the atmosphere to increase or with the free radical reaction in the atmosphere and form secondary aerosol pollutant, plays very important effect to the formation of pollutants such as ozone in the atmosphere and dust haze. In recent years, with the increasing discharge amount of VOCs and the clearer understanding of the harm of people, the control of China on VOCs is continuously strengthened. In the control and treatment of VOCs, direct combustion and catalytic combustion oxidation methods are the mainstream treatment methods. The direct combustion oxidation method has high combustion reaction temperature and large energy consumption in the operation process, and the application safety of the direct combustion oxidation method is also tested; the catalytic combustion oxidation method reduces the activation energy in the combustion oxidation reaction process by means of a catalyst, so that the oxidation temperature is obviously reduced, and the advantages in the aspects of safety and energy consumption are obvious.

The key to the catalytic combustion oxidation process of VOCs is the catalyst. The catalyst activity can be reduced due to carbon deposition, high temperature, particles, poisons and other factors during the use process. At present, deactivated catalysts are generally directly treated as hazardous wastes, and no report is provided about the activation and regeneration of the catalyst for catalytic oxidation of VOCs. The effective active components of the catalyst for treating VOCs are mainly noble metals such as platinum, palladium, rhodium and the like, are mostly imported and are expensive. The cost of the catalyst accounts for more than 1/2 of the operation cost of the whole set of VOCs treatment project, if the service life of the catalyst is greatly shortened due to inactivation, the cost of replacing a new catalyst is not small, and in addition, the cost of disposing the hazardous waste of the waste catalyst further increases the operation burden of enterprises for environment-friendly treatment facilities which do not generate or generate little economic benefit. If the deactivated catalyst is activated and regenerated, the service life of the catalyst can be prolonged, and the cost of the catalyst can be reduced by about 1/2 compared with the cost of the newly purchased catalyst.

aiming at Nitrogen Oxide (NO) generated by coal-fired power plant_x) The most widely used technique is Selective Catalytic Reduction (SCR), which is based on NH under the action of a denitration catalyst₃Or urea or the like as a reducing agent, selectively with NO using the reducing agent_xReaction takes place to convert NO_xReducing the nitrogen into nontoxic nitrogen. The current large-scale commercial denitration catalyst is mainly TiO₂as carrier, vanadium, tungsten and molybdenum are used as main active components. The denitration catalyst can be regenerated by adopting an off-line or on-line activation mode after being deactivated, and the regeneration mode comprises water washing, acid washing, thermal reduction, active component supplement and the like. Taking the regeneration mode of the supplementary active component as an example, the general operation is to wash the catalyst by using water or steam, spray a proper activating solution, dry and bake by using primary hot air or steam of a boiler.

However, in the field of catalytic oxidation treatment of VOCs, the treatment target is mainly derived from exhaust gas in workshops or tank areas of industries involving volatile organic compounds, such as petroleum refining, oil reservoirs, printing and dyeing. VOCs waste gas is heated to a certain temperature and is oxidized into CO by active oxygen under the action of a catalyst₂And H₂And O. The catalyst for catalytic oxidation of VOCs mostly uses cordierite, alumina, silica and the like as carriers, and noble metals such as platinum, palladium, silver and the like or manganese, cerium, cobalt, nickel and the likeTransition metal is an active component. Although the activation of the denitration catalyst has been reported, the composition of the catalyst for catalytic oxidation of VOCs is different from that of the denitration catalyst, the application environments of the catalyst and the denitration catalyst are different, and the reasons of catalyst deactivation are also different, so that the composition of an activating solution and the drying and roasting conditions are different. Therefore, a regeneration method of the denitrification catalyst cannot be fully introduced, but a rapid online regeneration method and process of the catalyst for catalytic oxidation of VOCs can be developed by taking the regeneration idea of the denitrification catalyst as reference, which is an inevitable trend of the development of the catalytic oxidation technology of VOCs.

Disclosure of Invention

In order to prolong the service life of the VOCs catalyst and avoid the defect of off-line activation, the invention provides an on-line activation method of the VOCs catalyst for catalytic oxidation, the deactivated catalyst does not need to be moved away from a catalytic reactor, and the deactivated catalyst is subjected to on-line activation regeneration by means of heat treatment, ash removal treatment, active component supplement and the like.

In order to achieve the purpose, the technical scheme of the invention is as follows:

An on-line activation method of a catalyst for catalytic oxidation of VOCs comprises the following steps:

Purging: blowing the deactivated catalyst for 2-3 h by using hot air at the temperature of 200-300 ℃, and removing oil stains and dust adsorbed on the catalyst;

Spraying: after purging is finished, after the catalyst is naturally cooled to normal temperature, spraying an activation supplementing liquid onto the catalyst at a speed of 15-60 mL/min, wherein the spraying amount is 30-60% of the weight of the catalyst carrier, standing overnight, and fully permeating the active components to be sprayed into the holes of the catalyst and the interior of the holes;

And (3) calcining: hot air with the temperature of 200-300 ℃ is utilized, and the air speed is 3000-7000 h^-1Calcining the catalyst sprayed with the activation replenishing liquid for 1-5 h under the condition of (1) to complete the online activation of the deactivated catalyst.

as an improvement of the invention: further comprising drying: before the catalyst sprayed with the activating supplementary liquid is calcined, hot air at the temperature of 60-120 ℃ is utilized, and the space velocity is 5000-10000 h^-1Catalysis of the spray activation make-up fluid under the conditions of (1)And drying the agent for 1-5 h. The drying aims to slowly and uniformly evaporate the water in the pores inside the catalyst, so that the phenomenon that the water is evaporated too fast to destroy the pore structure inside the catalyst so as to reduce the active surface area of the catalyst or sinter the catalyst is avoided, and meanwhile, the active components can be uniformly distributed in the catalyst, so that the uneven oxidation during direct calcination is avoided.

As a modification of the present invention, the spraying, drying and calcining are repeated at least once.

As an improvement of the invention, in the purging step, when carbon deposition exists in the deactivated catalyst, the temperature of hot air needs to be raised to 300-450 ℃ so as to relieve or eliminate the carbon deposition. Carbon deposit and other impurities are burnt at high temperature, so that the active components can be better attached to the surface and the inner holes of the catalyst.

As a modification of the invention, the hot air is obtained by heating air by using a preheating and heating system matched with the deactivated catalyst. Therefore, the method can be operated by utilizing the inherent equipment and the control system of the catalytic oxidation system, and does not need to add new facilities.

As an improvement of the invention, the activation make-up solution comprises 40-80 wt% of an active component precursor, wherein the active component precursor is at least one nitrate of silver, platinum, palladium, manganese, cobalt, cerium, nickel and copper.

Further, the active component of the activation make-up fluid comprises an active component of the deactivated catalyst.

furthermore, the activation make-up solution does not comprise an active component of the deactivated catalyst, but comprises a new active component which is not possessed by the deactivated catalyst and is introduced for improving the performance of the catalyst, and the content of the new active component in the activation make-up solution is 0.1-15 wt%.

As an improvement of the invention, the activation make-up solution realizes the in-situ spraying of the deactivated catalyst through a spraying circulation system matched with the deactivated catalyst or manual direct spraying, and the deactivated catalyst does not need to be moved away from the catalytic reactor. Therefore, the whole activation process is simple to operate, the catalyst does not need to be disassembled and assembled, and the workload is small.

Compared with the prior art, the invention has the beneficial effects that:

1. The method adopts on-line activation, comprises the processes of blowing, spraying, drying, calcining and the like, the consumed time is generally 2-4 days, the activation consumed time is short, and the normal production operation time of a waste gas front-end workshop is further influenced to be short.

2. The blowing, drying and calcining processes of online activation are directly operated by using the inherent equipment and the control system of the catalytic oxidation system, no new facility is needed, and the system can be automatically completed only by setting the opening and closing of a valve and the temperature; the spraying is finished through a preset spraying circulation system or manual spraying in the catalytic reactor, the whole activation process is simple to operate, the catalyst does not need to be disassembled and moved, and the workload is small.

3. After the deactivated catalyst is activated on line, toluene is used for simulating VOCs waste gas with the concentration of 400-500 mg/m³Airspeed of 10000h^-1Testing the performance of the activated catalyst, wherein test data shows that the performance of the activated catalyst can be recovered to more than 90% of the performance of a new catalyst product near the catalytic oxidation ignition temperature;

4. Through on-line activation, the service life of the catalyst can be prolonged by 1-1.5 years, the loss amount of the catalyst is reduced, and the running cost of the catalyst is reduced by 1/3-1/2.

Drawings

FIG. 1 is a comparison of the performance of group A and group B catalysts after on-line activation with liquid A.

FIG. 2 is a comparison of the performance of group A catalysts after on-line activation with A, B water.

FIG. 3 is a comparison of the performance of group C and group D catalysts after 1 and 2 on-line activations with liquid E.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

an on-line activation method for a catalyst for catalyzing and oxidizing VOCs (volatile organic compounds), which is used for reversible inactivation caused by moisture, carbon deposition, ash blockage, active component loss and the like in a period of time and carrying out in-situ on-line activation regeneration on the catalyst, and comprises the following steps:

(1) the method comprises the following steps of heating air to 200-300 ℃, preferably 250 ℃ by utilizing a preheating and heating system of a catalytic oxidation system, introducing hot air into a catalytic reactor to purge the deactivated catalyst, wherein the purging time is set to be 2-3 h so as to remove oil stains and dust adsorbed on the catalyst and promote better adsorption of subsequent activation make-up liquid on the catalyst;

In the purging process, if carbon deposition exists in the deactivated catalyst, the temperature of hot air needs to be raised to 300-450 ℃, preferably 300 ℃, so as to relieve or eliminate the carbon deposition, and active components can be attached to the surface and inner holes of the catalyst better;

(2) After purging is completed, after the catalyst is naturally cooled to normal temperature, spraying an activation supplement liquid onto the catalyst through a preset spraying circulation system in the reactor, wherein the spraying speed is 15-60 mL/min, and the 1-time spraying dosage of the activation supplement liquid is 30-60% of the weight of the catalyst carrier;

After 1 time of spraying, standing overnight, and fully permeating the sprayed active components into the holes of the catalyst and the interior of the catalyst;

(3) the method comprises the steps of utilizing a preheating and heating system of a catalytic oxidation system to heat air to 60-120 ℃, preferably 80 ℃, introducing hot air into a catalytic reactor to dry a catalyst of a spray activation replenishing liquid, setting the duration to 1-5 hours, preferably 4 hours, and setting the airspeed to 5000-10000 hours^-1The drying aims to slowly and uniformly evaporate the water in the pores in the catalyst, so that the phenomenon that the water is evaporated too fast to damage the pore structure in the catalyst so as to reduce the active surface area of the catalyst or sinter the catalyst is avoided, and meanwhile, the active components can be uniformly distributed in the catalyst so as to avoid uneven oxidation during direct calcination;

(4) After drying, raising the temperature of hot air to 200-300 ℃, preferably 250 ℃, calcining the dried catalyst for 1-5 h, preferably 4h, and setting the airspeed to 3000-7000 h^-1After the calcination is finished, the on-line activation of the deactivated catalyst is finished;

(5) In order to improve the activation effect, the steps (2) to (4) can be repeated one to more times.

The preparation of the activation make-up solution is determined according to the active components of the deactivated catalyst, the activation make-up solution contains 40-80 wt%, preferably 50-70 wt% of an active component precursor, and the active component precursor is at least one nitrate of silver, platinum, palladium, manganese, cobalt, cerium, nickel and copper. In addition, the active component of the activation replenishment solution may or may not be identical to the active component of the deactivated catalyst, and may even be completely different from the active component of the deactivated catalyst.

According to the VOCs catalyst on-line activation method, the processes of blowing, drying and calcining are directly operated by using the inherent equipment and control system of the catalytic oxidation system, no new facility is needed, and the system can be automatically completed only by setting the opening and closing of a valve and the temperature; the spraying can be completed through a spraying circulation system or manual spraying preset in the catalytic reactor, the whole activation process is simple to operate, the catalyst does not need to be disassembled and moved, the workload is small, the whole consumed time is generally 2-4 days, the activation consumed time is short, the catalyst can be operated even under the condition that the catalytic oxidation system is not shut down when necessary, the waste gas catalytic oxidation treatment system is short or not interrupted, and then the normal production operation of a workshop at the front end of waste gas is rarely or not influenced.

It should be noted that the above procedures of purging, spraying, drying and calcining can be flexibly selected according to the specific reasons of the deactivated catalyst, and can be used in combination or independently.

A number of examples of the above-described methods for on-line activation of VOCs catalysts will now be provided to further illustrate the present invention.