How to Solve Abnormal Valve Switching of Catalytic Combustion Equipment?

Abnormal valve switching is one of the frequent operational faults of catalytic combustion equipment, which may lead to unstable VOCs treatment efficiency, system overpressure, false alarm of PLC control system and even automatic shutdown of the whole waste gas treatment line. If the fault cannot be located and handled in time, the production schedule of factories will be disturbed and the emission indicators will fail to meet the standard. Many plant operators and maintenance engineers are looking for practical, step-by-step troubleshooting methods for RCO valve switching problems. Zhengzhou Puhua Technology, a professional environmental protection equipment manufacturer in Henan, focuses on the design, research, development and production of VOCs waste gas treatment equipment, including RCO catalytic combustion equipment, RTO equipment, baghouse dust collectors, desulfurization and denitrification equipment and sewage treatment equipment. We summarize practical on-site diagnosis and disposal experience to help users quickly deal with valve switching abnormality of catalytic combustion equipment.

Common Phenomena of Catalytic Combustion Equipment Valve Switching Abnormality

Before troubleshooting, maintenance staff should first confirm the specific fault phenomenon, which helps narrow down the checking scope efficiently. Typical abnormal manifestations are listed below:

• Valve cannot receive switching command and keeps static state

• Valve acts slowly and cannot reach the full open or full close position within the set time

• Valve switches in place but the feedback signal cannot return to the PLC system

• Valve jams halfway and triggers safety interlock protection of the catalytic combustion system

• Air leakage exists at the sealing surface after valve switching, accompanied by continuous hissing sound

Main Causes of RCO Valve Switching Abnormality

Valve switching failure of catalytic combustion equipment is mostly related to pneumatic supply, solenoid valve, actuator, mechanical structure and electrical signal. The following table sorts out common causes and simple judgment features for reference:

Step-by-step Operation Process to Handle Valve Switching Abnormality

On-site disposal must follow the safety-first principle. Cut off the heating and VOCs feeding of the catalytic combustion equipment and switch to the bypass state before maintenance operation to avoid high-temperature scalding and unorganized emission of waste gas. Follow the ordered steps below for inspection and repair:

1. Check the compressed air system. Confirm that the air pressure is kept within the normal range. Drain water and oil from the air storage tank and air filter, inspect all air pipes and joints for air leakage, and clean the blocked air pipeline.

2. Test the solenoid valve. Check whether the solenoid valve has power supply. Carry out manual test of the pilot head. Clean the internal sundries if the valve core is blocked, and replace the solenoid valve assembly when the coil or internal sealing is damaged.

3. Inspect the cylinder actuator. Disassemble and check the internal sealing parts of the cylinder. Replace aging and damaged sealing rings, and lubricate the moving parts according to the maintenance manual.

4. Check the mechanical part of the switching valve. Remove foreign matters clamped on the sealing surface. Calibrate the actuator stroke and limit position. Repair or replace the valve plate if permanent deformation occurs under high temperature.

5. Detect the electrical control loop. Fasten the loose wiring terminals, test the opening and closing limit feedback switch, check the intermediate relay and PLC signal output point, and reset or modify the control program parameters appropriately after confirming safety.

6. Carry out commissioning test after repair. Send continuous switching commands to the valve group, record the action time and feedback signal, and test the air tightness of the valve to ensure that the valve can switch stably and reliably.

Safety Notes During Fault Handling

Catalytic combustion equipment runs with high temperature and contains flammable VOCs waste gas. Operators need to abide by the following requirements during troubleshooting:

• Do not disassemble the valve body when the furnace body is still at high temperature

• Cut off the waste gas inlet in advance and open the bypass channel to prevent unqualified waste gas discharge

• Use explosion-proof tools in the waste gas treatment workshop with VOCs risk

• Do not shield the safety interlock function of the system for the sake of temporary production

• Record all fault information and maintenance contents for later equipment file archiving

Daily Maintenance Measures to Reduce Valve Switching Faults

Most valve switching faults can be avoided through standardized daily maintenance. Zhengzhou Puhua Technology recommends that users formulate a regular maintenance plan for RCO catalytic combustion equipment:

• Drain the compressed air system every day to reduce the impact of water and oil on pneumatic valves

• Check the action state and feedback signal of each switching valve every week

• Clean the solenoid valve and air filter regularly according to the dust concentration of on-site working conditions

• Replace the high-temperature resistant sealing parts of valves regularly according to the running time

• Carry out regular inspection for the whole VOCs governance system including dust removal equipment, desulfurization and denitrification supporting facilities

Conclusion

Abnormal valve switching is a common but controllable fault of catalytic combustion equipment. Most problems come from pneumatic supply, solenoid valve, cylinder, mechanical clamping and electrical signal. Systematic step-by-step inspection can help maintenance personnel locate the fault quickly. As a manufacturer providing complete sets of VOCs waste gas treatment solutions, Zhengzhou Puhua Technology provides RCO catalytic combustion equipment, RTO equipment, pulse dust collectors, low-emission treatment equipment and supporting after-sales technical services for different industries. If you encounter complex valve faults or need scheme consultation for VOCs treatment equipment, you can contact our technical team for professional support.