Currently, the organic emissions from industries such as petrochemicals, light industry, plastics, and printing... Waste gas treatment For direct-fired incinerators and regenerative thermal oxidizers (referred to as RTO ). The honeycomb ceramic in a regenerative thermal oxidizer can store the heat generated by the burner; when the ceramic temperature exceeds the ignition point of the organic exhaust gas, even in the absence of an open flame within the furnace, the incandescent honeycomb ceramic can ignite the organic exhaust gas. Regenerative thermal oxidizers offer advantages such as low energy consumption, high safety, and broad applicability, making them a highly promising method for treating VOC-containing gases.

1 VOC exhaust gas Current Situation Handling

Volatile organic compounds (VOCs) are the most common pollutants emitted from petrochemical processes and various industries that use organic solvents, such as painting, printing, pharmaceutical manufacturing, and coal chemical processing. Most of these compounds have a pungent odor and are toxic; some have even been classified as carcinogens. Furthermore, many VOCs are highly flammable and explosive, posing a significant threat to workplace safety.

Due to the hazards posed by VOCs, many countries have enacted regulations to control their emissions. In the 1990s, European and American countries introduced emission requirements for all applications involving organic solvents. In 1990, the United States tightened its air emission standards and designated 189 pollutants from industrial processes as toxic pollutants, most of which are VOCs. China’s Air Pollution Prevention and Control Law mandates the purification and treatment of toxic gases generated in industrial production and requires the recovery and utilization of combustible gases. Furthermore, China’s Comprehensive Emission Standard for Air Pollutants (GB 16297–1996) sets emission limits for 33 volatile organic compounds, treats most other VOCs as non-methane hydrocarbons, and establishes uniform emission standards for them.

2 Regenerative Thermal Oxidation Treatment Method

Thermal oxidation is a method that employs thermal and catalytic oxidation technologies to destroy organic compounds in exhaust emissions. A regenerative thermal oxidizer (RTO) differs from other thermal oxidation technologies currently used in China in that it utilizes a bed of ceramic or other high-density inert materials to absorb and store heat from the exhaust combustion gases, then transfers this stored heat to the incoming cold feed gas—rather than relying on shell-and-tube heat exchange between the two streams. As a result, RTOs can achieve a heat recovery efficiency of over 98%.

The operating principle of a regenerative thermal oxidizer is as follows: organic waste gas is preheated in a heat recovery chamber, then enters the combustion chamber for high-temperature oxidation (heated to 800°C), where organic compounds are oxidized into carbon dioxide and water. The treated gas then passes through another heat storage chamber to recover and store heat before being discharged; this stored heat is subsequently used to preheat the incoming organic waste gas. By periodically reversing the flow direction of the gas stream, the furnace temperature is maintained at a stable level.

Typical regenerative thermal oxidation processes include the following, namely the integrated regenerative incineration process flow. (One chamber), as shown in Figure 1 [2]; the regenerative split-type incineration process flow (two chambers), as shown in Figure 2 [2]; and the regenerative integrated incineration process flow (three chambers), as shown in Figure 3 [3].

Characteristics of 3RTO

3.1 Large exhaust gas treatment capacity and high efficiency

RTO is ideally suited for treating organic waste gases at concentrations of 2–8 g/m³; for low-calorific-value gases such as ethyl acetate, the concentration can be as high as 12 g/m³. It is particularly well suited for the incineration of refractory components [3]. Compared with other treatment technologies—such as heat-exchanger-based thermal oxidation—the primary advantage of RTO lies in its exceptionally high heat recovery rate, which can reach 98%, whereas other systems typically achieve only about 70%. This high heat recovery significantly reduces the amount of supplemental fuel required, thereby lowering operating costs. The benefits are especially pronounced when treating large gas streams with low organic content.

To ensure a high fly ash removal rate (Destroyed Removal Efficiency, DRE)—RTOs’ high heat recovery efficiency also confers the advantage of maintaining elevated thermal oxidation temperatures. This facilitates the treatment of recalcitrant organic compounds while incurring only a modest increase in operating costs. A DRE of 98% to 99% is a hallmark of such systems. In RTO systems, achieving very high preheating temperatures within the packed bed enables the thermal oxidation process to occur directly within the bed itself; these systems typically maintain preheating temperatures well above the autoignition temperatures of most organic compounds.

3.2 Energy-saving, environmentally friendly, and easy to maintain

The application results show that, for a given size, In RTO applications, structured packing offers the following advantages over random packing: (1) higher thermal efficiency, which can reduce annual fuel costs by 60% to 65%; (2) lower pressure drop, which can reduce annual electricity costs by 14% to 78%; and (3) reduced clogging propensity and enhanced cleaning performance, leading to shorter downtime and lower maintenance expenses. However, structured packing is more expensive to manufacture and install, with a unit-volume cost that is 5 to 10 times that of conventional random packing. Consequently, the capital investment for structured packing is 5% to 20% higher than that for random packing.

4. Application of RTO in China

Currently, most of the exhaust-gas incinerators used in China’s insulation-material and copper-clad laminate industries are direct-fired incinerators. Although such incinerators have a relatively low capital cost, they also consume substantial amounts of fuel. With fuel prices continuing to soar, fuel conservation and cost reduction have become critical priorities for every enterprise. In fact, as long as a heat-storage medium is added to the direct-fired incinerator, (Honeycomb ceramic) can effectively achieve fuel savings. When a regenerative heat storage unit is added to a direct-fired exhaust gas incinerator, it not only serves as a heat storage device but also acts as a secondary ignition source: when the burner “flames out,” organic exhaust gases will ignite and burn upon contact with the hot honeycomb ceramic. The cost of converting a direct-fired exhaust gas incinerator into a regenerative-type incinerator is very low; therefore, all direct-fired exhaust gas incinerators currently used in China’s insulating materials industry and copper-clad laminate manufacturing industry can and should be retrofitted.

5 Conclusion

Regenerative thermal oxidation technology offers distinct advantages over conventional direct-fired incineration. While this technology is well established internationally, its widespread adoption in China has been hindered by high costs, and the regenerative concept is currently applied only in a limited number of industrial kilns. Against the backdrop of soaring energy prices, concerted efforts to research, develop, and promote the application of this technology would not only conserve energy and reduce environmental pollution but also deliver substantial economic benefits and significant social returns.