Technology

— Industrial production processes generate various types of volatile organic compounds (VOCs). Depending on the concentration and airflow rate of the exhaust air, treatment methods may include condensation, adsorption and concentration, concentrated combustion, or direct combustion. Refer to the chart on the right to select the appropriate treatment method.

Activated Carbon Adsorption System (ADS)

— The Tenzon ADS-G/C/F is a multi-bed adsorption concentration system comprising the granular activated carbon ADSG, honeycomb activated carbon ADS-C, and fibrous activated carbon ADS-F systems. The system integrates adsorption and concentration units with thermal oxidation units in a cohesive manner, primarily targeting high-volume, low-concentration organic exhaust air. After adsorption and purification, the exhaust air is discharged in compliance with standards. Before the adsorption bed becomes saturated, it undergoes cyclic desorption/deadsorption, converting the gas into a low-volume, high-concentration stream, which is then treated via catalytic or thermal combustion before being discharged in compliance with standards.

Process Flow

— High-volume, low-concentration organic exhaust air is fed into an activated carbon adsorption bed, where it comes into full contact with honeycomb-structured activated carbon for purification. After desorption and regeneration, the gas is converted into a low-volume, high-concentration stream and sent to a catalytic combustion bed for oxidation. At temperatures above 280°C, the organic compounds are oxidized and decomposed into harmless gases such as carbon dioxide and water. The hot exhaust air from combustion passes through a heat exchanger to heat cold air. After heat exchange, part of the cooled gas is discharged, while the remainder is used for the desorption and regeneration of the activated carbon, thereby achieving waste heat recovery and energy conservation.

MSD Zeolite Rotor Adsorption Unit

— Tenzon independently developed next-generation VOC treatment system, the MSD-P/D rotary adsorption and concentration system, utilizes honeycomb-shaped zeolite adsorbent material to efficiently adsorb VOCs from exhaust air through the adsorption and concentration method. The system is available in two configurations: the multi-disk rotary MSD-P and the single-disk rotary MSD-D. This system organically integrates adsorption-concentration and thermal oxidation units. It is primarily designed for high-volume, low-concentration organic exhaust air. The system continuously adsorbs and purifies the exhaust, then desorbs it to convert it into a low-volume, high-concentration stream. This concentrated stream is then subjected to thermal oxidation treatment, and the heat released from the combustion of organic compounds is effectively utilized.

Process Flow

— exhaust air containing VOCs enters the zeolite rotor via a fan. The zeolite rotor adsorbs the VOCs, and the purified gas is discharged directly into the atmosphere. The zeolite rotor rotates continuously; when the saturated section of the rotor passes through the desorption zone, desorption occurs. The regenerated gas is heated by a secondary heat exchanger, raising its temperature to 180°C. The desorbed gas passes through the first-stage heat exchanger and is then directly combusted in the incinerator, where it is heated to 750°C. At this high temperature, the exhaust air is completely decomposed into CO₂ and H₂O (thermal combustion treatment).

Catalytic Combustion Unit TCO/RCO

— Catalytic oxidation (Catalytic Oxidizers, CO) is a combustion treatment technology that works by completely oxidizing volatile organic compound (VOC) pollutants at a specific temperature with the aid of a catalyst, breaking them down into carbon dioxide and water. Removal efficiency can reach over 95%. This technology employs a partition-type heat exchange method for the inlet and outlet air to minimize heat loss. Generally, the heat recovery efficiency of this type of catalytic combustion ranges from 40% to 65%.

— Tenzon heat-exchange type TCO and regenerative type RCO catalytic combustion bed series feature compact structures, high purification efficiency, and low operating costs. These systems are suitable for applications where exhaust air composition frequently changes due to varying products or where exhaust air concentrations fluctuate significantly.

Process Flow

— Heat-exchange TCO: Organic exhaust air are preheated via a heat exchanger before entering the electric heating chamber. After being heated to approximately 300°C, the gases are fed into the catalytic combustion chamber, where the high-temperature organic exhaust air are decomposed into CO₂, water vapor, and other compounds under the action of a catalyst, and then discharged through a stack. 

— Regenerative RCO: Organic exhaust air first absorb heat from Regenerator I, which was stored during the previous cycle. After being heated, the gases enter the catalytic bed, where catalytic combustion occurs at approximately 300°C to 500°C, oxidizing the organic compounds into carbon dioxide and water. The heat generated by combustion is transferred to Regenerator I for storage. After one cycle is complete, the gas flow direction is reversed: the gas absorbs heat from heat storage bed I, and the heat released by the combustion reaction is stored in heat storage bed I. By periodically reversing the gas flow direction, the stability of the catalytic reaction is ensured, thereby guaranteeing the purification efficiency of the organic waste gas.

Thermal Combustion PAI/TNV

— PAI, which stands for Polluted Air Incinerator, is one of the equipment types used in Tenzon exhaust air treatment systems.

— The flue gas outlet temperature of the PAI is relatively high; therefore, multi-stage heat exchangers are often connected to the outlet as needed to provide functions such as heating air.

— Due to the unique characteristics of the PAI, which differ from other combustion furnaces, it is commonly used for exhaust air treatment and heating in paint curing systems, often referred to as a “one-to-three” configuration (where one incinerator provides heat to three or more heating furnaces).

— PAI operates on the same principle as TNV but features a different structure; PAI has lower internal resistance than TNV, resulting in reduced power consumption for the fan.

— The PAI combustion chamber is separated from the heat exchanger, which does not come into contact with the flame, making it less susceptible to high-temperature damage. This separation also facilitates easier maintenance and lower maintenance costs, though the system occupies a larger footprint.

— In a PAI system, exhaust air remain at 750°C for up to 1.0 seconds, ensuring thorough mixing and achieving an exhaust air treatment efficiency of over 99%. In contrast, the residence time in a TNV system is approximately 0.5 seconds, resulting in slightly lower treatment efficiency. Consequently, oil condensation is less likely to occur inside fresh air furnaces using the PAI design.

Regenerative Thermal Oxidizer (RTO)

— An RTO (Regenerative Thermal Oxidizer) is a regenerative thermal oxidation/combustion furnace. It works by oxidizing organic waste gases (VOCs) into corresponding oxides and water at high temperatures (approximately 760°C), thereby purifying the exhaust air. The exhaust air purification efficiency exceeds 99%, and the heat recovery efficiency exceeds 95%.

Process Flow

— The organic exhaust air is heated to over 760°C, where the VOCs are oxidized and broken down into carbon dioxide and water     
— The high-temperature gas produced by oxidation flows through ceramic heat storage media, causing the ceramic bodies to heat up and “store heat”; heat recovery efficiency is approximately 95%     
— The RTO design effectively controls the “3Ts”: temperature, residence time, and turbulence coefficient