Precautions for catalytic combustion application process

Mainly using incinerators to burn or oxidize organic waste gas into water and CO2 under the action of catalysts, suitable for organic waste gas purification in industries such as enameled wire, machinery, motors, chemicals, instruments, automobiles, engines, plastics, and electrical appliances.

Catalytic combustion is an ideal method for treating organic pollutants through catalytic reactions (without open flames) due to its low ignition temperature. It has the advantages of wide applicability, simple structure, high purification efficiency, energy saving, and no secondary pollution, and has been widely used both domestically and internationally. The catalytic combustion purification device developed by our company has simple operation, high automation program, and can effectively treat various organic waste gas pollutants with a treatment concentration of<=10g/m3, which is highly welcomed by customers. Structure and principle of catalytic combustion treatment technology: The catalytic combustion purification device mainly consists of flame arresters, heat exchangers, catalytic reaction beds, and fans. Compared with direct combustion, catalytic combustion has lower temperature and more complete combustion. The catalysts used for catalytic combustion are precious metals and metal oxides with high specific surface area. Catalytic combustion method is to oxidize organic pollutants in exhaust gas into carbon dioxide and water at lower temperatures under the action of catalysts such as platinum and palladium.

Catalytic combustion is a typical gas-solid phase catalytic reaction, which essentially involves deep oxidation with the participation of reactive oxygen species. In the process of catalytic combustion, the role of the catalyst is to reduce the activation energy, and at the same time, the catalyst surface has adsorption effect, which enriches the reactant molecules on the surface and increases the reaction rate, accelerating the progress of the reaction. With the help of catalysts, organic waste gas can undergo flameless combustion at lower ignition temperatures, and be oxidized and decomposed into CO2 and H2O, while releasing a large amount of heat energy, thus achieving the method of removing harmful substances from the waste gas. In the process of catalytic combustion of exhaust gas, the exhaust gas is sent to a heat exchanger through a pipeline by a fan, heated to the ignition temperature required for catalytic combustion, and then burned through a catalyst bed. Due to the presence of the catalyst, the ignition temperature of catalytic combustion is about 250-300 ℃, which is much lower than the combustion temperature of 650-800 ℃ in direct combustion method. Therefore, the energy consumption is much lower than that of direct combustion method.

Catalytic combustion method, abbreviated as RCO, is an effective means of purifying organic waste gases such as hydrocarbons and eliminating odors by decomposing VOCs into CO2 and H2O at low temperatures of 200-400 ℃ under the action of catalysts. It is widely used in the purification of organic waste gas, especially in industries with low recycling value, such as chemical, painting, insulation materials, enameled wire, and coating production.

Characteristics of catalytic combustion performance

1. Using platinum and palladium metal plating on honeycomb ceramic carriers as catalysts, the purification efficiency is as high as 97-99%, the equipment has a long service life, is renewable, and has low gas flow resistance;

2. Complete facilities: fire retardant dust collector, pressure relief hole, over temperature alarm and other protective facilities are fully equipped;

3. Preheat for 15-30 minutes for full power heating. During operation, only the visible power consumption is required. When the exhaust gas concentration is low, automatic intermittent compensation heating is applied;

4. Waste heat can be returned to the drying oven for drying work, reducing power consumption in the original drying oven; It can also be used for thermal energy reuse in other aspects of the factory

Precautions for catalytic combustion treatment

1. The exhaust gas components must not contain the following substances:; There are high viscosity oils and fats. Such as phosphorus, bismuth, arsenic, antimony, mercury, lead, tin; High concentration dust;

2. When selecting equipment, indicate the composition, concentration, and outlet temperature of the exhaust gas;

3. The equipment installation site is free of corrosive gases and has good rainproof measures;

4. The required power supply for the equipment is three-phase AC 380V with a frequency of 50Hz;

Scope of application of catalytic combustion

1. Used for purifying organic solvents such as mixed organic waste gases of benzene, alcohols, esters, phenols, ethers, alkanes, etc;

2. Suitable for organic waste gas purification in industries such as enameled wire, machinery, motors, chemicals, instruments, automobiles, engines, plastics, and electrical appliances;

3. Suitable for various drying channels, printing inks, motor insulation treatment and other drying assembly lines.

catalytic combustionWaste gas treatment equipmentThe important role of catalysts is that the principle of catalytic combustion reaction is that organic waste gas is completely oxidized and decomposed under the action of catalysts at lower temperatures, achieving the purpose of gas purification. Catalytic combustion is a typical gas-solid phase catalytic reaction, which is based on the participation of reactive oxygen species in deep oxidation. In the process of catalytic combustion, the role of the catalyst is to reduce the activation energy of the reaction and enrich the reactant molecules on the surface of the catalyst to increase the reaction rate. With the help of catalysts, organic waste gas can burn without flame at lower ignition temperatures and release a large amount of heat, while oxidizing and decomposing into CO2 and H2O.

1. What is a low-temperature catalyst

Low temperature catalyst performance indicators: ignition temperature ≤ 200 ℃, oxidation conversion efficiency ≥ 95%, pore density 200-400cpsi, compressive strength ≥ 8MPa.

The role and influence of VOCs catalysts in catalytic combustion systems

The self combustion temperature of VOCs is usually high. By activating the catalyst, the activation energy of VOCs combustion can be reduced, thereby lowering the ignition temperature, reducing energy consumption, and saving costs.

In addition, the combustion temperature (in the absence of a catalyst) is generally above 600 ℃, which produces nitrogen oxides, commonly known as NOx, which are pollutants that need to be strictly controlled. Catalytic combustion is combustion without open flames, generally below 350 ℃, and there will be no NOx generation, making it safer and more environmentally friendly.

3. Pre treatment of exhaust gas can extend the catalyst andCatalytic combustion equipmentAnalysis of the causes of lifespan

The exhaust gas may contain some harmful components to the catalyst. If such chemicals are known to exist, pre-treatment of the exhaust gas is necessary, otherwise these harmful components will have a significant impact on the lifespan of the catalyst.

The exhaust gas should undergo pre-treatment (dust removal, oil removal, and dehumidification) before entering the catalytic chamber. Dust, carbon deposits, and high boiling viscous substances adhere to the surface of the catalyst, covering the active sites of the catalyst, which can lead to catalytic activity. Therefore, the introduction of dust and high boiling viscous substances should be avoided as much as possible.

In high humidity environments, water vapor and oil mist paint mist are prone to interact with catalysts at high temperatures, causing catalyst sintering deactivation. Therefore, efforts should be made to minimize the entry of water vapor and oil mist paint mist into the catalyst bed.

The Importance of Controlling Exhaust Gas Concentration in Catalytic Combustion Systems

Appropriate exhaust gas concentration can ensure the safe and efficient treatment of exhaust gas in catalytic combustion systems, while also helping to extend the service life of equipment and catalysts.

Low concentration: A large amount of energy is used to heat the air, resulting in high energy consumption and insufficient heat release from the reaction to maintain the system's self heating combustion. It is recommended to concentrate the exhaust gas in this condition.

Excessive concentration: risk of explosion; Excessive temperature rise and combustion temperature (exceeding 600 degrees for a long time) can cause damage to equipment and catalysts. It is recommended to dilute the exhaust gas with fresh air to below the lower explosive limit for this condition.

5. Precautions for starting and stopping catalytic combustion equipment

Before starting the system, preheat the catalyst with fresh air, and then preheat the exhaust gas to above 250 degrees before introducing it into the catalytic chamber; Before stopping the system, cut off the exhaust gas, continue heating the catalyst and introduce fresh air, keep it warm for 0.5 hours, and then cut off the power.

6. Explanation of catalyst poisoning

Certain chemical substances can poison catalysts, such as organic or inorganic substances containing phosphorus, sulfur, lead, mercury, arsenic, and halogens, which have a strong destructive effect on catalysts and can lead to catalyst deactivation, making it impossible to restore activity.

7. Factors affecting the lifespan of catalysts

Please strictly follow the instructions for the use of the catalyst. The factors that affect the lifespan of catalysts include: the pre-treatment status of exhaust gas, i.e. the cleanliness of the exhaust gas, the temperature of the catalytic chamber, the toxicity of halogens and catalysts, and the operating procedures of catalytic combustion equipment.

Main performance indicators of catalysts

Under high airspeed and low temperature conditions, the conversion rate of the combustion reaction of organic waste gas is close to 100%, indicating that the activity of the catalyst is high [9]. The activity of catalysts is divided into three stages: induced activation, stability, aging and deactivation, with a certain service life. The lifespan of practical catalysts in industry is generally more than 2 years. The length of the usage period is related to the stability of the active structure, which depends on the ability to resist heat and toxicity. The catalyst used for catalytic combustion requires high heat resistance and anti toxicity performance. The catalytic combustion of organic waste gas is generally not carried out under very strict operating conditions, as the concentration, flow rate, and composition of the waste gas are often unstable. Therefore, catalysts are required to have a wide adaptability to operating conditions. The operating speed of catalytic combustion process is relatively high, and the impact force of gas flow on the catalyst is strong. At the same time, due to the temperature rise and fall of the bed layer, it causes thermal expansion and contraction, which is easy to cause the catalyst carrier to break. Therefore, the catalyst needs to have high mechanical strength and good resistance to thermal expansion and contraction.