Common VOCs end-of-pipe treatment processes include regenerative thermal oxidization (RTO), catalytic combustion (RCO), direct combustion (TO), activated carbon adsorption, condensation, biological treatment and their combination technologies. Due to the complex composition of VOCs waste gas, it may be a variety of flammable and explosive mixed organic (based on actual reports) gases. If the technical process is not properly selected or the operation and maintenance of these devices are not managed, there will be safety hazards.
RTO (Regenerative Thermal Oxidizer, regenerative incinerator) system is increasingly widely used in the VOCs treatment industry, but explosion accidents occur frequently. RTO furnace refers to a device that burns and purifies industrial organic (based on actual reports) waste gas, absorbs and releases combustion heat by using a heat storage body, heats up the waste gas to be treated, and heats up the purified gas. The RTO furnace system includes: RTO furnace body, burner, fan, lifting valve, purge valve, fresh air valve, bypass cut-off valve, emergency discharge facilities, hot bypass valve, chimney, pipeline, electrical (distribution cabinet, operating column, etc.), automatic control (PLC or DCS), instrumentation (temperature, pressure, flow, hydrocarbon analyzer, etc.), etc.
RTO furnace safety points
Source: “Regenerative Incinerator (RTO Furnace) Safety Points” (Communication Emergency Letter [2020] No. 13)
RTO furnace safety facilities should be designed, constructed and put into use at the same time as the main project. In-use RTO furnaces should be supplemented with safety risk assessment demonstration: For waste gas with complex components, HAZOP analysis should be conducted and corresponding safety measures should be taken.
RTO furnaces can strictly control the concentration and flow rate of organic matter (based on actual reports) at the inlet of RTO furnaces by setting up buffer tanks, adjusting air volume and other pre-treatment facilities to ensure relatively stable and safe operation.
The RTO furnace should take effective measures to prevent condensation and deposition in the pipeline and the lower chamber of the RTO furnace.
The RTO furnace should meet the lower ventilation requirements through forced ventilation measures to avoid the accumulation of combustibles, tempering, etc.
The RTO furnace should be equipped with a PLC or DCS control system (a safety instrument system can be set as appropriate) to monitor and interlock the key parameters of equipment and facilities such as fans, valves, burners, furnaces and exhaust pipes in real time. The safety instrument system of key equipment should be designed not less than SIL2 standard.
The electrical instrument equipment on site of the RTO furnace should be strictly designed according to the explosion-proof (based on actual reports) level, and explosion-proof plates should be installed in the pipeline or furnace; the RTO furnace should be equipped with short-circuit protection and grounding protection functions, and the selection of exhaust gas pipelines should pay attention to anti-static (based on actual reports).
The RTO furnace should be equipped with emergency closure of the air intake valve and exhaust valve after power failure and gas failure to prevent the chimney effect from causing the temperature of the lower part of the heat storage layer to rise.
The RTO furnace should be equipped with a UPS backup power supply and a compressed air storage tank. For emergency exhaust pipes containing high-concentration and low-ignition-point substances, it is strictly prohibited to share chimney emissions with high-temperature exhaust pipes.
