How to Ensure Safe Peanut Drying with a Belt Dryer System
Core Safety Regulations (Peanut Drying Specific Risks)
Dust Explosion Prevention: Dust generated from broken peanuts is combustible. The drying chamber must ensure there are no dead corners for dust accumulation and require regular, thorough cleaning.
Static Electricity Protection: All operating tools must be anti-static. Equipment grounding resistance must be <4Ω. Test the grounding system weekly.
Heat Source Isolation: The natural gas combustion chamber and the drying zone must be completely isolated. A spark trap must be installed at the hot air inlet.
1.1 Food Safety and Hygiene Requirements
Material Requirements: All components that contact the material must be made of food-grade stainless steel (304/316). Materials containing harmful substances such as lead and cadmium are strictly prohibited.
Chemical Requirements: Cleaning agents and lubricants used for maintenance must be NSF H1 food-grade certified to ensure no contamination of peanut products.
Cleaning Verification: Thorough cleaning and inspection must be performed after maintenance to prevent tools or parts from being left inside the equipment, causing food safety hazards.
Special Procedures for Shutdown and Startup
Emergency Shutdown: Upon detecting a burnt peanut smell or abnormal smoke, immediately initiate the emergency shutdown procedure: First, cut off the gas supply, stop the mesh belt, and turn off the fan.
Long-term Shutdown: For shutdowns exceeding 24 hours, all peanut kernels on the mesh belt must be emptied to prevent moisture absorption, spoilage, or microbial growth.
Restart Verification: After a long-term shutdown, the machine must run empty for 30 minutes to verify temperature uniformity and normal mesh belt operation before feeding for production.
1.2 Peanut Drying Process Parameter Benchmarks (Maintenance Reference Standards)
Chapter 2: Daily Maintenance (Per shift execution, 30-minute shutdown)
2.1 Pre-production Inspection (Mandatory before startup)
Gas and Combustion System:
- Use a portable gas leak detector to check valve groups and connections.
- Check for accumulation of peanut shells or broken kernels near the burner (fire hazard).
- Verify the flame detector sensitivity, ensuring the safety shutoff valve closes within 2 seconds.
Mesh Belt System Special Inspection:
- Check mesh hole clogging rate (clogging due to peanut oil/fouling should be <3%).
- Inspect the mesh belt surface for residual peanut debris or oil stains from the previous shift.
- Manually rotate the belt one full cycle, observing the gap between the mesh belt edge and the guide strip (should be uniform, 3-5mm).
- Ensure the mesh belt tensioning device indicator is within the green range.
2.2 Production Monitoring (Record hourly)
Chapter 3: Weekly Maintenance (Planned shutdown 3-4 hours)
3.1 In-depth Combustion System Maintenance (Special Focus for Peanut Drying)
Burner Disassembly and Inspection:
- Remove the burner nozzle, check for clogging caused by carbonized peanut oil/fouling.
- Use a borescope to inspect the inner wall of the combustion chamber and remove carbon deposits (thorough cleaning is required if the carbon layer exceeds 1mm).
- Check ignition electrodes, adjust spacing to 3.5-4.5mm.
Air-Fuel Ratio Optimization:
- Use a flue gas analyzer to adjust to an optimal combustion state (O₂ 3.5-4.5%, CO <30ppm).
- Adjust the combustion load based on peanut variety (high-oleic/regular).
- Record gas consumption data after optimization.
3.2 Weekly Inspection of Mesh Belt and Drive System
Chapter 4: Monthly Maintenance (Planned shutdown 8 hours)
4.1 Comprehensive Gas System Check
Gas Pipeline Inspection:
- Inspect all welds and joints on gas pipelines (using soapy water or a leak detector).
- Clean the gas filter, check the filter element (replace if pressure differential >10kPa).
- Calibrate the gas flow meter and pressure transmitter.
Heat Exchanger Efficiency Evaluation:
- Measure the temperature difference at the heat exchanger inlet and outlet, and calculate thermal efficiency (should be >85%).
- Clean the dust between the heat exchanger fins (peanut dust readily adheres).
- Check heat exchange tubes for corrosion or leakage.
4.2 Monthly Maintenance of Mesh Belt Drive System
Chapter 5: Annual Overhaul (Planned shutdown 24-48 hours)
Optimal Timing for Annual Maintenance
Suggested Time: During the peanut production off-season, typically March-April or September-October each year.
Preparation Work: Develop a detailed maintenance plan one month in advance, prepare necessary spare parts and tools.
Personnel Arrangement: Led by the equipment supervisor, with participation from all maintenance team members. Equipment manufacturer technical support may be requested if necessary.
5.1 Comprehensive Overhaul of Gas and Combustion System
Professional Burner Maintenance:
- Commission the manufacturer or a professional agency for comprehensive disassembly and repair.
- Replace all seals and ignition transformer (if reaching service life).
- Perform professional inspection and repair of the combustion chamber refractory material.
- Calibrate all burner control parameters.
Gas System Safety Verification:
- Hire a qualified inspection agency for a comprehensive inspection.
- Perform a tightness test on gas pipelines at 1.5 times the working pressure.
- Update calibration labels for all safety valves. Replace expired pressure gauges and safety valves.
Chapter 6: Common Fault Diagnosis and Handling
6.1 Analysis and Handling of Peanut Drying Quality Issues
Emergency Situation Handling Process
Step One: Immediately press the emergency stop button, cut off the equipment power, and the gas supply.
Step Two: Evacuate personnel on site, ensure a safe distance (at least 10 meters).
Step Three: Report to the equipment supervisor and the safety department, describing the fault.
Step Four: Wait for professional personnel to handle; unauthorized resumption of operation is prohibited.
Step Five: Record fault details for subsequent analysis and prevention.
Core Summary Points
Safety is the Bottom Line: Balance gas safety and dust explosion prevention. Daily inspections must not be relaxed.
Hygiene is the Lifeline: All maintenance must comply with food-grade requirements to prevent cross-contamination.