Electrical Tar PrecipitatorMultiple Faults May Occur In Industrial Operation. The Following Is A Detailed Analysis Of Common Fault Types, Causes, And Solutions To Help Quickly Locate And Handle Problems:
1、 Electrical System Malfunction
1. High Voltage Power Supply Cannot Boost (voltage Cannot Rise)
Fault Phenomenon: After Closing, The Voltage Can Only Rise To A Lower Value (such As The Rated Voltage Of 60kV, Which Can Only Rise To 30kV), And The Current Is Too Small.
Possible Reason: The Dust Content In The Gas Is Too High (>100mg/m ³), Causing "corona Blockage" And Capturing Electrons By Dust Particles, Making It Difficult To Effectively Charge Tar. The High Humidity Of Gas Leads To A Decrease In Breakdown Field Strength, Requiring Higher Voltage To Maintain Operation. The Cathode Wire Relaxes And Droops, Reducing The Distance Between It And The Anode Plate, And Causing Micro Discharges Due To Excessive Local Electric Field Strength. The Deformation Of The Cathode Frame Or Suspension Rod Results In Uneven Electrode Spacing. Insulation Ceramic Bottles/quartz Tubes May Experience Condensation, Oil Accumulation, Or Corrosion, Resulting In A Decrease In Insulation Resistance (normally>500M Ω, Measured<100M Ω). The Wall Sleeve Is Not Tightly Sealed, Causing Gas To Seep In And Lead To Discharge.
Insulation Component Failure:
Abnormal Electrode System:
Poor Gas Conditions:
Solution: Heat Up And Dry The Insulation Parts (such As Using A Hot Air Gun To Heat The Porcelain Bottle To Above 100 ℃), Clean The Surface Tar And Dust. Adjust The Tension Of The Cathode Wire, Correct The Deformation Of The Frame, And Ensure That The Electrode Spacing Meets The Design Value (such As Electrode Spacing Of 250-300mm For Tubular Equipment). Pre Dust Removal Equipment (such As Cyclone Separator) Is Used To Reduce The Dust Content Of Gas To Below 50mg/m ³.
2. High Voltage Tripping (short Circuit Or Overcurrent)
Fault Phenomenon: Voltage Drop And Current Surge During Operation, Automatic Power-off Protection Of The Equipment.
Possible Cause: Tools Or Parts Left Inside The Equipment During Maintenance May Come Into Contact With The Electrodes, Causing A Short Circuit. The Insulation Porcelain Bottle Is Broken Or Internally Carbonized, Causing High-voltage Electrical Leakage And Grounding. The Cable Terminal Is Damp Or Aged, And The Insulation Layer Is Broken. The Cathode Wire Breaks And Falls Off, Directly Contacting The Anode Plate (commonly Seen In Tubular Equipment Where The Cathode Wire Falls Into The Bottom Of The Tube). Tar Or Dust Accumulates Between The Electrode Plates, Forming A "conductive Bridge" (which Is Prone To Occur When The Electrode Plate Spacing Is Less Than 20mm).
Solution: After Shutdown, Use An Endoscope To Inspect The Electrodes, Replace The Broken Cathode Wire, And Remove Oil And Dust Accumulation Between The Electrode Plates. Test The Insulation Resistance Of Insulation Components And Replace Damaged Porcelain Bottles Or Cables (insulation Resistance Should Be ≥ 500M Ω). Strictly Implement The Post Maintenance Cleaning System To Avoid Foreign Objects Being Left Behind.
2、 Mechanical Structural Failure
1. Cathode Wire Breakage Or Detachment
Fault Phenomenon: Abnormal Noise (such As "crackling" Discharge Sound) Is Emitted During The Operation Of The Electric Field, Voltage Fluctuations Are Large, And The Capture Efficiency Decreases.
Possible Reasons:
Material Issue: Using Ordinary Carbon Steel Cathode Wire Without Anti-corrosion Treatment, It Is Corroded By H ₂ S In Coal Gas (with An Annual Corrosion Rate Of Over 0.5mm).
Stress Fatigue: Frequent Starting And Stopping Of Equipment Leads To Repeated Thermal Expansion And Contraction Of The Cathode Wire, Resulting In Breakage At The Suspension Point.
Improper Dust Cleaning During Vibration: Excessive Vibration Force (such As Pneumatic Vibration Pressure>0.4MPa) Or High Vibration Frequency (such As>5 Times Per Hour) Can Cause Metal Fatigue.
Solution: Replace With 316L Stainless Steel Or Titanium Alloy Cathode Wire, And Nickel Chromium Plating On The Surface To Enhance Corrosion Resistance.
Optimize The Start Stop Process To Reduce Unnecessary Downtime; Adjust The Vibration Parameters (such As Air Pressure 0.2~0.3MPa, Frequency Once Every 2 Hours).
2. Uneven Distribution Of Airflow
Fault Phenomenon: There Is A Significant Difference In Tar Accumulation In Different Areas Of The Equipment (such As A Tar Thickness Of 5mm On One Side Of The Electrode Plate And Only 1mm On The Other Side), And The Tar Content At The Outlet Exceeds The Standard.
Possible Reasons: Design Flaws In The Inlet Pipeline: The Elbow Is Less Than 3 Times The Diameter Of The Equipment Inlet, Resulting In Gas Deviation (flow Rate Difference>20%).
Blockage Of Distribution Plate: Dust Or Tar Clumps Block The Holes Of The Distribution Plate (such As Reducing The Diameter Of The Hole From 20mm To 10mm Due To Oil Accumulation).
Detachment Of Flow Guide Plate: The Welding Joint Of The Internal Flow Guide Plate Of The Equipment Cracks, Losing The Function Of Uniform Flow.
Solution: Install Guide Vanes Or Rectifying Grilles In Front Of The Inlet To Ensure That The Cross-sectional Flow Velocity Uniformity Is Greater Than 90% (flow Velocity Deviation<± 10%). Regularly Clean The Distribution Plate (such As Blowing With Steam Every Week), And Replace It With An Orifice Plate Structure That Is Not Prone To Oil Accumulation If Necessary (such As A Diameter Of 30mm And A Spacing Of 50mm Between Holes).
3、 Tar Capture And Discharge Malfunction
1. Poor Tar Discharge/blockage
Fault Phenomenon: The Temperature Of The Drain Pipe Is Low (<40 ℃), There Is No Flow When Touched, And The Pressure Difference At The Bottom Of The Equipment Increases (>500Pa).
Possible Reasons:
Tar Solidification: When The Gas Temperature Is Too Low (<70 ℃), The Viscosity Of Tar Increases Sharply (such As Reaching 1000cSt At 50 ℃, Much Higher Than 100cSt At 80 ℃), And Condenses In The Pipeline.
Blockage Of Debris: The Valve Core Of The Drain Valve Falls Off, Welding Slag Or Rust Mixes Into The Pipeline.
Water Seal Failure: The Liquid Level In The Water Seal Tank Is Too High, Which Hinders The Discharge Of Tar; Or The Liquid Level Is Too Low, Resulting In Gas Backflow.
Solution: Heat Tracing And Insulation Should Be Applied To The Drainage Pipe And Water Seal Tank (maintaining A Temperature Of 80-90 ℃), And The Pipeline Should Be Regularly Purged With Steam (such As Once A Week). Replace With Ball Valve Or Gate Valve (to Avoid Valve Core Detachment), And Install A Y-shaped Filter (filter Aperture<2mm) To Filter Impurities. Adjust The Water Seal Level To The Design Height (such As The Overflow Port Height Being 300mm Higher Than The Bottom Of The Equipment).
2. Severe Water Carryover In Tar
Fault Phenomenon: The Moisture Content Of The Discharged Tar Is Greater Than 10% (normal<5%), And Even Visible Water Appears.
Possible Reason: The Condensed Water During Gas Freezing Was Not Effectively Separated And Entered The Electric Tar Catcher With The Gas. The Accumulated Water At The Bottom Of The Equipment Was Not Drained In Time And Mixed With Tar.
Solution: Install A Pre Steam Water Separator, Set Up A Water Collection Bag Before The Gas Inlet, And Regularly Drain Water (such As Once Every 2 Hours).
Raise The Bottom Drainage Outlet Of The Equipment Or Add A Slope Guide Plate To Ensure That Accumulated Water Is Discharged First.
4、 Safety And Corrosion Issues
1. Alarm For Excessive Oxygen Content In Gas
Fault Phenomenon: Oxygen Content Detector Alarm (>1.0%), Equipment Interlock Shutdown.
Possible Reasons: Gas Pipeline Leakage, Inhalation Of Air; Or Water Seal Damage, Air Backflow. Detector Probe Failure (such As Expiration Of Electrochemical Probe Life And Decreased Sensitivity).
Solution: Use Soapy Water To Check For Leaks And Repair The Leaks; Check If The Water Seal Level Meets The Design Requirements (such As An Effective Height Of 500mm). Regularly Calibrate The Oxygen Content Meter (e.g. Once Every 3 Months) And Replace Expired Probes.
2. Corrosion And Leakage Of The Shell
Fault Phenomenon: Rust, Bulges Or Leaks Appear On The Outer Wall Of The Equipment, And There Is A Gas Odor.
Possible Reason: The Shell Material Is Ordinary Carbon Steel, Which Has Not Undergone Anti-corrosion Treatment And Has Been Corroded By SO ₂ And H ₂ S In Coal Gas (with An Annual Corrosion Rate Of Up To 0.3~0.5mm). The Anti-corrosion Coating Falls Off (such As Aging And Cracking Of Epoxy Resin Paint), And The Metal Comes Into Direct Contact With Corrosive Gases.
Solution: Polish And Remove Rust From The Corroded Area, Apply Glass Flake Adhesive Or Polyurea Anti-corrosion Layer (thickness ≥ 1.5mm). Partially Replaced With Stainless Steel Plates (such As 316L) To Protect The Gas Inlet, Bottom, And Other Easily Corroded Areas.
By Establishing Standardized Inspection And Maintenance Procedures, Combined With Real-time Monitoring Of Equipment Operation Data, The Failure Rate Of Electric Tar Precipitators Can Be Significantly Reduced, Ensuring Their Efficient And Safe Operation.
