CN103706368A - Iron-carbon catalytic filler for treating organic mixed exhaust gases and preparation method of filler - Google Patents

Abstract

The invention belongs to the technical field of catalytic decomposition of organic waste gas by iron-carbon micro-electrolysis, and in particular relates to an iron-carbon catalytic filler for treating organic mixed waste gas and a preparation method thereof. The finished filler is composed of the following components by mass percentage: 80-85% iron filings, 10-15% activated carbon, 0.1-0.3% rare earth metal, 1-5% clay; the diameter of the iron-carbon micro-electrolytic filler is 3.0-6.0cm . The obtained iron-carbon micro-electrolytic filler has good gas penetration mesh path, strength, specific surface area and galvanic reaction effect, and since the iron atoms do not directly contact each other, the passivation of the filler surface and the hardening of the filler can be effectively prevented.

Description

An iron-carbon catalytic filler for treating organic mixed waste gas and its preparation method

technical field

The invention belongs to the technical field of catalytic decomposition of organic waste gas by iron-carbon micro-electrolysis, and in particular relates to an iron-carbon catalytic filler for treating organic mixed waste gas and a preparation method thereof.

Background technique

In the industrial production process, a large number of high-temperature evaporation and concentration processes are used. During the high-temperature evaporation and concentration process of the liquid rich in organic matter, part of the organic matter is cracked to form volatile organic compounds (VOCs) and the water vapor and inorganic salts generated during the evaporation process to form a mixed malodorous gas. cause great harm to the environment. The existing reported VOCs treatment methods mainly include:

(1) Direct combustion method: It is a method that uses high temperature oxidation to convert VOCs into CO ₂ and H ₂ O. After VOCs gas enters the combustion chamber, it is a process of complete combustion under the conditions of high enough temperature, excess air and turbulent flow.

(2) Catalytic oxidation method: The principle of action is basically similar to that of the direct combustion method, except that a honeycomb or sheet catalyst needs to be installed in the reactor. Thanks to the use of catalysts, it can run at lower temperatures, reducing auxiliary fuel consumption and operating expenses.

(3) Biological method: It uses microorganisms to oxidize organic matter into CO ₂ and H ₂ O under aerobic conditions. The reaction process is similar to the oxidation method, but instead of using heat, it uses biology to destroy VOCs.

(4) Absorption method: It is a method of absorbing gaseous VOCs from the airflow by using a liquid absorption liquid, and is often used to treat high-humidity VOCs airflow (>50%).

(5) Adsorption method: It is a method to adsorb VOCs by using the huge surface area of the adsorbent pore structure. It is suitable for treating organic waste gas with a single composition and a stable gas flow with a concentration of 300-5000ppm.

(6) Concentration method: It is a way to saturate the VOCs airflow by cooling or pressurization, and it is often used together with other treatment methods. It is generally used to deal with VOCs gases with a higher boiling point and a concentration of more than 5%.

(7) Membrane method: It is a process in which the membrane selectively blocks the size of VOCs gas molecules, and can partially or completely intercept VOCs.

However, in the organic waste gas containing a large amount of water vapor, due to the interference and masking effect of water vapor, none of the above methods can achieve effective treatment of VOCs.

Micro-electrolysis technology uses the principle of metal corrosion to form a primary battery to electrochemically treat organic matter through a series of actions. In an environment containing a conductive electrolyte, iron filings and carbon particles form countless tiny primary batteries, forming an electric field in their action space, and the new ecological [H], Fe ²⁺ , etc. undergo redox reactions with organic substances in the environment , destroy some groups in the organic matter, or even break the chain, so as to decompose the organic matter; the generated Fe ²⁺ is further oxidized to Fe ³⁺ , and their hydrates have a strong adsorption and flocculation effect to achieve the adsorption of organic matter .

The mixed flue gas formed by high-temperature evaporation and concentration is composed of VOCs, water vapor and inorganic salts. A water environment of inorganic salts is formed on the surface of the filler. A weak internal molecular current will be generated between iron atoms and carbon atoms. The [H], Fe ²⁺ , etc. undergo a redox reaction with the organic matter adsorbed on the surface of the iron-carbon particles, realize the decomposition of the organic matter and produce an adsorption flocculation effect, and detach from the surface of the iron-carbon particle with the droplet.

Contents of the invention

The purpose of the present invention is to use iron filings, powdered activated carbon, aerobic activated sludge, rare earth metal powder, and clay as raw materials to provide an iron-carbon micro-electrolytic filler and its Preparation. The filler has good gas penetration mesh path, strength, specific surface area and galvanic reaction effect, and because the iron atoms do not directly contact each other, it can effectively prevent the passivation of the filler surface and the hardening of the filler.

To achieve the above object, the present invention adopts the following technical solutions:

An iron-carbon catalytic packing for treating organic mixed waste gas, using iron filings, powdered activated carbon, aerobic activated sludge, rare earth metal powder, and clay as raw materials, the finished packing is composed of the following components in mass percentage: iron Chips 80-85%, activated carbon 10-15%, rare earth metal 0.1-0.3%, clay 1-5%; iron-carbon micro-electrolytic filler has a diameter of 3.0-6.0cm.

Preferably, the iron-carbon catalytic filler for treating mixed organic waste gas, its finished filler is composed of the following components in mass percentage: 80-85% of iron filings, 10-15% of activated carbon, 0.15-0.2% of rare earth metal, clay 2 to 4%.

Preferably, the activated carbon is powdered activated carbon with a particle size of 80-120 mesh.

Preferably, the rare earth metals include Ce, La, Pr, and Nd, and the rare earth metals are in powder form, and the particle size of the rare earth metal powders is 90-130 mesh.

Preferably, the particle size of the iron filings is 50-100 mesh.

The aerobic activated sludge is aerobic activated sludge from a domestic sewage treatment plant, with a moisture content of <60%.

The preparation method of the iron-carbon catalytic filler for treating organic mixed waste gas comprises the following steps:

1) Pickling the iron filings with hydrochloric acid with a mass concentration of 6-4% for 20-30 minutes to activate the iron filings, rinse them clean,

2) Using iron filings, activated carbon powder, rare earth metal powder, aerobic activated sludge and clay as raw materials respectively, according to mass percentage: iron filings 55-65%, powdered activated carbon 8-11%, rare earth metal powder 0.1-0.2% , aerobic activated sludge (dry basis) 23-35%, clay 1.5-3%, fully stirred and mixed.

3) Use a double-roll granulating extruder to extrude under a pressure of 210kN-250KN to form a granular blank filler with a diameter of 3-6cm.

4) After the rough filler is dried, it is baked at 1000-1200°C for 1-3 hours in an air-free environment, and the catalytic micro-electrolytic filler is obtained after cooling.

Preferably, the pressure in step 3) is 210-220KN.

Preferably, the air-free environment described in step 4) includes vacuum and inert gas environment. The inert gas environment includes nitrogen and argon environments.

Preferably, in step 4), calcining is performed at 1000-1100° C. for 2 hours.

Aerobic activated sludge is mainly composed of aerobic microbial organisms, which are carbonized into CO ₂ in a high-temperature environment, and the roasted filler forms a mesh gas channel. Since the activated sludge in the filler disappears, the quality of each component of the finished filler The ratio is changed to: iron filings 80-85%, activated carbon 10-15%, rare earth metal 0.1-0.3%, clay 1-5%. Aerobic activated sludge plays the role of template agent in the preparation process of electrolytic filler. The choice of template agent has a great influence on the mesopore structure, thus affecting the catalytic effect. After a lot of experiments, we unexpectedly found that the use of aerobic activated sludge can not only realize the recycling of waste and reduce the discharge of three wastes, but also double the specific surface area of the obtained iron-carbon micro-electrolytic filler, which is beneficial to the original battery. Reaction.

The beneficial effects of the present invention are:

1. The filler prepared by the present invention is a granular filler with internal mesh, which is beneficial to the distribution of gas, and the specific surface area is doubled, which is beneficial to the reaction of the primary battery.

2. The filler prepared by the present invention contains rare earth metal elements, which can promote the galvanic reaction efficiency of the filler and prevent the passivation of the filler surface.

3. The filler prepared by the present invention has a certain strength when calcined at high temperature, and can maintain its inherent shape during the reaction.

4. Since the filler prepared by the present invention does not directly contact the iron atoms, the hardening phenomenon during the operation of the filler is prevented.

5. The present invention utilizes activated sludge and realizes recycling of waste.

Detailed ways

The present invention will be further described below in conjunction with embodiment.

Example 1:

First, pickle the iron filings with hydrochloric acid with a mass concentration of 6% for 20 minutes to activate the iron filings. Ce powder, aerobic activated sludge and clay are used as raw materials. According to the mass percentage of each raw material component: iron filings 55.3%, powdered activated carbon 8%, rare earth metal powder 0.1%, aerobic activated sludge (dry basis) 35%, Clay 1.6%, fully stirred and mixed, extruded by a double-roller granulating extruder under a pressure of 210kN to form a granular blank filler with a diameter of 3cm, after the blank filler is dried, bake it at 1000°C for 2 hours in a vacuum environment , made of qualitative catalytic micro-electrolysis filler after cooling.

Aerobic activated sludge is mainly composed of aerobic microbial organisms, which are carbonized into CO ₂ in a high-temperature environment. The roasted filler forms a mesh gas channel. As the activated sludge in the filler disappears, the ratio of the components of the finished filler changes. It is: iron filings 85%, activated carbon 12.24%, rare earth metal 0.16%, clay 2.6%.

Example 2:

First, pickle the iron filings with hydrochloric acid with a mass concentration of 4% for 30 minutes to activate the iron filings. La powder, aerobic activated sludge and clay are used as raw materials. According to the mass percentage of each raw material component: iron filings 60%, powdered activated carbon 11%, rare earth metal powder 0.1%, aerobic activated sludge (dry basis) 27.8%, Clay 2%, fully stirred and mixed, extruded by a double-roller granulating extruder under a pressure of 220kNKN to form a granular blank filler with a diameter of 6cm, after the blank filler is dried, it is roasted at a temperature greater than 1200°C for 1 hour in a nitrogen environment , made of qualitative catalytic micro-electrolysis filler after cooling.

Aerobic activated sludge is mainly composed of aerobic microbial organisms, which are carbonized into CO ₂ in a high-temperature environment. The roasted filler forms a mesh gas channel. As the activated sludge in the filler disappears, the ratio of the components of the finished filler changes. It is: iron filings 82.1%, activated carbon 15%, rare earth metal 0.12%, clay 2.78%.

Example 3:

First, pickle the iron filings with hydrochloric acid with a mass concentration of 5% for 25 minutes to activate the iron filings. Nd powder, aerobic activated sludge and clay are used as raw materials. According to the mass percentage of each raw material component: iron filings 65%, powdered activated carbon 9%, rare earth metal powder 0.15%, aerobic activated sludge (dry basis) 23%, Clay 2.85%, fully stirred and mixed, extruded by a double-roll granulating extruder under a pressure of 250KN to form a granular blank filler with a diameter of 5cm. After the blank filler is dried, it is roasted at a temperature greater than 1100°C in an argon environment. After cooling for 3 hours, a qualitative catalytic micro-electrolysis filler was made.

Aerobic activated sludge is mainly composed of aerobic microbial organisms, which are carbonized into CO ₂ in a high-temperature environment. The roasted filler forms a mesh gas channel. As the activated sludge in the filler disappears, the ratio of the components of the finished filler changes. It is: iron filings 84.1%, activated carbon 11.8%, rare earth metal 0.25%, clay 3.75%.

Example 4:

The iron-carbon micro-electrolysis organic waste gas catalytic decomposition filler prepared in Example 1 was used to treat the glutamic acid fermentation waste liquid and the foul-smelling tail gas at the end of spray granulation.

After the glutamic acid fermentation waste liquid is concentrated and evaporated at high temperature, it is sprayed and granulated under high temperature conditions (500-550°C) to produce organic-inorganic compound fertilizers. However, during the high-temperature evaporation process, the organic matter in the fermentation waste liquid is coked, forming a foul smell The gas evaporates together with the water vapor, and the pH of the foul-smelling flue gas is 3 to 4. When it enters the decomposition tower filled with iron-carbon particles, countless tiny primary batteries are formed on the surface of the iron-carbon particles, and the generated [H], Fe ²⁺ and other organic substances in the flue gas undergo a redox reaction to decompose the VOCs in the flue gas. The operation results show that the bad smell is controlled, the internal mesh granular filler maintains good permeability, and there is no hardening phenomenon.

After using the iron-carbon micro-electrolysis organic waste gas prepared in Example 1 to catalytically decompose the filler in an amino acid fermentation factory, the emission indicators detected by the environmental protection department on site are as follows: particulate matter: 17.33 mg/m ³ , sulfur dioxide 0 mg/m ³ , nitrogen oxides 0 mg /m ³ , benzene 0 mg/m ³ , anilines 0 mg/m ³ , non-methane total hydrocarbons 1.32 mg/m ³ , ammonia 0.3 mg/m ³ . The measured data is significantly better than the first-level standards in the national standards of the People's Republic of China "Comprehensive Emission Standards for Air Pollutants" (GB16297-1996) and "Emission Standards for Odor Pollutants" (GB14554-93).

Example 5:

Use the iron-carbon micro-electrolysis organic waste gas catalytic decomposition filler prepared in implementation 1 to treat the fermentation gas in the pharmaceutical industry, and pass the waste gas discharged from the fermentation tank into the spray decomposition tower equipped with iron-carbon particle filler, and the pH of the spray at the top of the tower is 3 The absorption liquid forms countless tiny primary batteries on the surface of iron carbon particles, and the generated [H], Fe ²⁺ , etc. undergo redox reactions with the organic matter in the fermentation waste gas, so that the VOCs in the waste gas are decomposed, and after a certain period of operation , the pH value rises, and the spray liquid is replaced regularly. The operation results show that the peculiar smell in the exhaust gas is eliminated, and the internal mesh granular filler does not appear hardened. After being used in a pharmaceutical fermentation enterprise, the emission indicators detected by the environmental protection department on site are as follows: particulate matter: 15mg/m ³ , sulfur dioxide 0mg/m ³ , nitrogen oxides 0mg/m ³ , benzene 0mg/m ³ , aniline 0mg/m ³ , non-methane total hydrocarbons 1.21mg/m ³ , ammonia 0.78mg/m ³ . The measured data is significantly better than the first-level standards in the national standards of the People's Republic of China "Comprehensive Emission Standards for Air Pollutants" (GB16297-1996) and "Emission Standards for Odor Pollutants" (GB14554-93).

Although the specific implementation of the present invention has been described above, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art can do it without creative work. Various modifications or deformations are still within the protection scope of the present invention.

Claims (9)

1. An iron-carbon catalytic filler for treating mixed organic waste gas, the finished filler is composed of the following components in mass percentage: iron filings 80-85%, activated carbon 10-15%, rare earth metal 0.1-0.3%, clay 1 ~5%; the diameter of the iron-carbon micro-electrolytic filler is 3.0-6.0cm. 2. as claimed in claim 1, is used to process the iron-carbon catalytic packing of mixed organic waste gas, it is characterized in that, the iron-carbon micro-electrolytic packing of described organic mixed waste gas treatment, its finished packing is made up of the component of following mass percent: Iron filings 80-85%, activated carbon 10-15%, rare earth metal 0.15-0.2%, clay 2-4%. 3. The iron-carbon catalytic filler for treating mixed organic waste gas according to claim 1 or 2, wherein the activated carbon is powdered activated carbon with a particle size of 80-120 mesh. 4. The iron-carbon catalytic filler for treating organic mixed waste gas as claimed in claim 1 or 2, wherein the rare earth metals include Ce, La, Pr, Nd, and the rare earth metals are powdery, with a particle size of It is 90-130 mesh. 5. The iron-carbon catalytic filler for treating mixed organic waste gas according to claim 1 or 2, characterized in that the particle size of the iron filings is 50-100 mesh. 6. the preparation method of the iron-carbon catalytic filler that is used to process organic mixed exhaust gas described in claim 1, comprises the following steps: 1) Pickling the iron filings with hydrochloric acid with a mass concentration of 6-4% for 20-30 minutes to activate the iron filings and rinse them clean; 2) Using iron filings, activated carbon powder, rare earth metal powder, aerobic activated sludge and clay as raw materials respectively, according to mass percentage: iron filings 55-65%, powdered activated carbon 8-11%, rare earth metal powder 0.1-0.2% , aerobic activated sludge (dry basis) 23-35%, clay 1.5-3%, fully stirred and mixed; 3) Extrude with a double-roll granulating extruder under a pressure of 210kN-250KN to form a granular blank filler with a diameter of 3-6cm; 4) After the rough filler is dried, it is baked at 1000-1200°C for 1-3 hours in an air-free environment, and the catalytic micro-electrolytic filler is obtained after cooling. 7. The method for preparing iron-carbon catalytic packing for treating mixed organic waste gas according to claim 6, characterized in that the pressure in step 3) is 210-220KN. 8. The preparation method of iron-carbon catalytic filler for treating mixed organic waste gas according to claim 6, characterized in that the air-free environment described in step 4) includes vacuum and inert gas environment. The inert gas environment includes nitrogen and argon environments. 9. The preparation method of iron-carbon catalytic filler for treating mixed organic waste gas according to claim 1, characterized in that, in step 4), it is roasted at 1000-1100°C for 2 hours.