Regenerative Thermal Oxidizer Automatic Startup Procedure

Author: Environmental Technology Engineering Department
Published: January 15, 2026

Table of Contents

I. Pre-Startup Inspection Operations

 1. Pre-Power On Inspection Items

 2. Equipment Power-On Procedure

 3. Post-Power On Inspection Items

 4. Post-Startup Operational Checks

II. Startup Procedure

 1. Pre-Startup Precautions

 2. Automatic Startup Sequence

III. Automatic Shutdown Procedure 

I. Pre-Startup Inspection Operations
1. Pre-Power On Inspection Items
  1) Check and confirm compressed air pressure and supply are normal and reliable. Regularly inspect and maintain all pneumatic components to ensure they are in good condition.

• Observe the compressed air pressure gauge as shown in the figure below.

• Note: Lack of compressed air will cause automatic protection actions to lose power, preventing control actions from being executed and posing an overheating risk. Therefore, loss of compressed air will trigger an automatic shutdown of the RTO equipment.
• Regularly inspect and remove any condensate accumulated in the compressed air piping.                                                                                              

  2) For initial use, confirm natural gas pressure is normal. The normal pressure before entering the burner should be approximately 40-60 KPa. Figure shows the natural gas pressure gauge.                                                                                                  
  3) Inspect the burner control cabinet. Confirming the combustion system is in good condition, the burner controller is in remote automatic control mode, and all buttons/switches are in their correct positions. Please refer carefully to the burner operation manual.
  4) Before starting up, check the tightness of the wiring terminals inside the electrical cabinet. This inspection should also be performed at least every six months. If any loose terminals are found, tighten the screws immediately to prevent issues that could lead to RTO shutdown or equipment damage.
  5) Conduct a perimeter check of the equipment to eliminate any hazardous factors around the mechanical structures.

2. Equipment Power-On Procedure
  1) Open the G1 inner cabinet door and inspect the surge protector status.

• Check that the four monitoring indicator windows on the surge protector show a white color mark.   
• Ensure the backup circuit breaker for the surge protector is in the closed position, as shown in the figure. 
• If a red light is displayed, it indicates that a lightning protection breakdown has occurred. Replace the surge protector promptly to ensure safety.

  2) Connect to the power supply.

• Personnel operating the main power switch must possess appropriate electrical safety knowledge.
• Before closing the main circuit, complete all the above inspections and ensure safety conditions are met before powering on the equipment.

    The figure shows the main power supply switch.

3. Post-Power On Inspection Items
After powering on the equipment, inspect the following items and perform corresponding operations.
  1) Check that the PLC and control interface start up normally.

•  Check if the power indicator lights on each PLC module illuminate normally.
•  Check if the touchscreen lights up normally and displays the startup welcome screen, as shown in Figure 5.5.

  2) After normal power-on, the RTO should be in a ready state. All RTO motors and valves should be in their initial power-off state. Listen to ensure no motors are unexpectedly running.
  3) Check if the burner section powers on normally. Both the main control and high-limit temperature controllers should light up normally.
  4) Check the actual status of valves F0101 and F0102. Ensure they are not stuck and are not in the process of exhaust intake position.
  5) Check the actual position of valve F0103 for any sticking, especially if the unit has been idle for an extended period.
  6) Check the display status of the inlet pressure transmitter.

4. Inspection Items After Initiating RTO Automatic Operation
  (1) Check the actual operating status of all motors.
  (2) Check that all components are functioning and operating normally.
  (3) Monitor pressure and temperature changes to ensure they are normal.
If any abnormalities are found, stop the operation and conduct an inspection.

II. Startup Procedure

 Since the PLC has a state memory function and peripheral large motors, inductors, capacitors, etc., have certain time-delay effects, ensure an interval of no less than 120 seconds between consecutive restarts and the previous shutdown operation.
Before pressing the system start button, ensure the pre-power-on inspections per the previous chapter are completed. If the main circuit was not disconnected after the last equipment shutdown, or if an emergency stop was performed last time, it is necessary to disconnect the main circuit once, then re-power on and complete all the inspection and monitoring processes described in the previous chapter.
The burner control box has a separate power supply that can be powered on independently. Under normal circumstances, it must remain turned on. It should only be turned off independently in emergencies. The Remote/Local switch on the burner control box must always remain in the Remote position to allow PLC automatic control. The Local position is only for debugging and must be operated by qualified personnel.
After completing the inspections and correct power-on as per Chapter 5, initiate the burner controller program. To prevent excessive furnace temperature ramp-up rates, which can affect furnace life, check the difference between the burner control command and the actual oxidizer chamber temperature each time the automatic start button is pressed. If the difference exceeds 100°C, it is necessary to power off the burner section locally, then re-power it on locally to restart the burner controller program action, preventing excessively rapid temperature rise that could damage the furnace.
During automatic startup, ensure the 'Exhaust Intake' key is in the Off position, and all interlock statuses are ready. Pressing the [System Run] key initiates the system automatically, performing the following startup sequence:
   

   1. Verify that all interlock signals (production line, compressed air, and motor protector status) are ready, and the production line Voc Gas intake status is set to the Off position.
   2. If all interlock signals are ready, the automatic startup process begins. Pressing [System Run] automatically closes the high-temperature bypass valve.
   3. Wait 3 seconds, then start the rotary valve motor and the high-temperature cooling fan.
   4. Wait 20 seconds, then start the combustion air fan.
   5. Wait 40 seconds, then start the purge fan.
   6. Wait 20 seconds, then start the main fan, running at the set "Main Fan Purging Frequency" for the duration determined by the purging time setting.
   7. After the main fan starts, the heat exchange fan begins operation.
   8. After purging ends, the system sends an ignition command to the burner.
   9. Upon successful burner ignition, temperature ramp-up control follows the heating curve. Once the temperature reaches the third-stage target temperature, process exhaust can be introduced. The typical exhaust introduction temperature is 800°C, but the final temperature should be determined based on actual site conditions.
   10. The automatic startup process is complete. Temperature is now automatically regulated.
   11. After all valves enter automatic control mode, the main fan begins to accept control based on the inlet pressure differential.

III. Automatic Shutdown Procedure
Pressing the [System Stop] button initiates the following automatic shutdown sequence:
  1. The shut-off valve closes the process exhaust line, the fresh air valve opens, and the high-temperature bypass valve opens.
  2. Wait 10 seconds, then the burner stops. The furnace chamber begins cooling down.
  3. When the oxidizer chamber temperature falls below the "Oxidizer Chamber Shutdown Temperature", the main fan stops.
  4. Wait 10 seconds, then turn off the purge fan.
  5. Wait until the oxidizer chamber temperature drops below the set "Oxidizer Chamber Auto-Shutdown Temperature" (typically set to ≤100°C), then turn off the combustion air fan.
  6. Wait 10 seconds, then turn off the rotary valve motor and the high-temperature cooling fan. The automatic shutdown process is complete.