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Maintenance Guide for Industrial High-Temperature Resistant Heat Exchangers (Suitable for Heat-Exchanging Fuel-Fired Hot Air Furnace Systems)
Release time:
2025-09-29
It details daily, regular and special maintenance of industrial high-temperature heat exchangers, including safety specs and after-sales, for hot air furnace systems.
As a core heat-exchanging component of heat-exchanging fuel-fired (biomass, coal) hot air furnaces, the stable operation of industrial high-temperature resistant heat exchangers directly affects the thermal efficiency of hot air furnaces and the stability of production processes. To ensure the equipment maintains a heat exchange efficiency of over 85% for a long time and extends its service life, this maintenance guide is formulated based on the equipment's working principle (countercurrent/cross-flow heat exchange between flue gas and air, compatible with jet/convection and other heat exchange tube structures) and application scenarios (high-precision industries such as pharmaceuticals, food, and lithium batteries).
I. Daily Maintenance: Daily Inspection to Prevent Minor Issues from Escalating
Daily maintenance should focus on "working condition monitoring + basic cleaning", with emphasis on identifying immediate issues that affect heat exchange efficiency to ensure the equipment starts and operates stably every day.
| Maintenance Item | Maintenance Content | Operation Standards & Precautions |
| Operation Parameter Monitoring | 1. Record in real-time the air temperature before and after heat exchange (inlet ~850℃, outlet as per process requirements) and flue gas temperature; 2. Check the frequency of the exhaust fan and the pressure of the power transmission equipment (air supply fan); 3. Observe whether the flue gas flows smoothly outside the heat exchange tubes and if there are signs of local dust accumulation | 1. If the air temperature difference deviates from the process setting by ±5%, immediately investigate (e.g., whether the exhaust fan frequency is abnormal, whether the air volume matches); 2. When the fan pressure fluctuation exceeds ±0.02MPa, shut down the machine to check if the fan impeller is dusty or jammed; 3. Forcibly operating the equipment when parameters are abnormal is prohibited to avoid local overheating and burning of the heat exchange tubes |
| External Cleaning | 1. Clean the heat exchanger shell and surrounding debris to ensure good heat dissipation of the equipment; 2. Check if there is flue gas leakage at the equipment's connecting flanges and seals (judged by "no obvious high temperature when touched by hand" and "no black smoke escaping") | 1. Power off and shut down the machine during cleaning; avoid touching high-temperature components (the shell temperature may reach 60~80℃, so heat-resistant gloves must be worn); 2. If aging of seals is found (e.g., cracks, deformation), immediately replace them with high-temperature resistant gaskets of the same specification (fluororubber gaskets with heat resistance ≥200℃ are recommended) |
| Linked Inspection of Auxiliary Equipment | 1. Check if the feeder feeds evenly to prevent unburned fuel from causing black smoke to adhere to the heat exchange tubes; 2. Confirm the normal operation of the high-temperature gas secondary combustion device (no unburned carbon black particles enter the heat exchanger) | 1. If the material layer height of the feeder deviates from the set value, adjust the speed of the transmission mechanism to ensure fuel enters the burner at a constant speed; 2. If carbon black particles are found in the flue gas (black scale on the outside of the heat exchange tubes), first overhaul the secondary combustion device, then clean the heat exchanger |
II. Regular Maintenance: Periodic In-Depth Maintenance to Ensure Core Performance
Based on the equipment operation intensity (it is recommended to conduct basic maintenance once a week and in-depth maintenance once a month), conduct special inspections and maintenance on core components such as heat exchange tubes, fans, and sealing systems to avoid long-term accumulation of problems such as dust accumulation and wear.
| Maintenance Cycle | Maintenance Part | Maintenance Content | Operation Standards & Precautions |
| Weekly | Outside of Heat Exchange Tubes (Flue Gas Side) | 1. Purge dust outside the heat exchange tubes with compressed air (pressure 0.4~0.6MPa); 2. Check if the heat exchange tubes have local deformation or corrosion (focus on the heat exchange tubes in the area corresponding to the secondary combustion device to prevent burning damage) | 1. During purging, remove the heat exchanger inspection door; ensure the compressed air gun is perpendicular to the heat exchange tubes to avoid scratching the tube walls; 2. If local discoloration of the tube walls is found (e.g., dark red burning marks), record the location and focus on checking it during the next in-depth maintenance |
| Monthly | Inside of Heat Exchange Tubes (Air Side) | 1. Remove the air inlet end cover and rinse dust and impurities inside the tubes with a high-pressure water gun (water temperature ≤60℃, pressure 0.8~1.0MPa); 2. Check if there is scaling on the inner walls of the heat exchange tubes (especially in the food and pharmaceutical industries, to prevent material residue scaling from affecting heat exchange) | 1. After rinsing, use compressed air to dry the accumulated water inside the tubes to avoid residual water causing tube wall rust; 2. If the scale is thick (thickness ＞2mm), soak it with food-grade descaling agents (e.g., citric acid solution) before rinsing; using highly corrosive agents is prohibited |
| Monthly | Fan System (Exhaust Fan, Air Supply Fan) | 1. Clean dust on the fan impeller and check the impeller wear condition; 2. Check the fan bearing grease (high-temperature resistant grease with heat resistance ≥150℃ is selected); replace the grease if it deteriorates (turns black, agglomerates); 3. Test the fan start-stop function and frequency adjustment accuracy | 1. The amount of bearing grease added should be 1/2~2/3 of the internal space of the bearing; excessive grease may cause bearing overheating; 2. If the fan frequency adjustment deviation exceeds ±1Hz, contact technical personnel to calibrate the frequency converter |
| Quarterly | Sealing and Connecting Components | 1. Replace all flange gaskets (it is recommended to keep spare seals of the same specification to avoid shutdown waiting); 2. Check if there is leakage at the connection between the heat exchange tubes and the tube sheet; if leakage is found, re-tighten or repair by welding (welding rods of the same material as the heat exchange tubes, such as 304 stainless steel welding rods, should be used for repair welding) | 1. Before replacing the gaskets, clean the flange sealing surface to ensure no debris or scratches; 2. After repair welding, conduct penetrant testing (PT) on the welds to prevent weld cracks from causing leakage |
III. Special Maintenance: Addressing Abnormal Working Conditions and Industry-Specific Needs
In response to sudden equipment failures (e.g., sharp drop in heat exchange efficiency, flue gas leakage) and cleanliness requirements of industries such as pharmaceuticals and food, special maintenance measures must be taken to avoid affecting production processes and product quality.
| Maintenance Scenario | Maintenance Measures | Operation Standards & Precautions |
| Sharp Drop in Heat Exchange Efficiency (Drop ＞10%) | 1. Conduct a comprehensive inspection of scaling and blockage inside and outside the heat exchange tubes, and clean them thoroughly; 2. Check if the secondary combustion device is normal (if secondary combustion is insufficient, flue gas containing carbon black is likely to block the heat exchange tubes); 3. Calibrate temperature sensors and pressure sensors to ensure accurate parameter detection | 1. After cleaning, re-test the heat exchange efficiency until it is restored to over 85%; 2. If the secondary combustion device fails, repair it first before starting the heat exchanger to prevent unburned particles from further polluting the heat exchange tubes |
| Flue Gas Leakage (Flange, Tube Sheet Areas) | 1. Emergency shutdown and cool down to room temperature (to avoid component deformation caused by disassembly at high temperature); 2. Check the leakage point; if the gasket fails, replace it immediately; if there is leakage at the tube sheet weld, repair by welding; 3. Conduct an air tightness test after repair (inject compressed air at a pressure of 0.3MPa, maintain pressure for 30 minutes; a pressure drop ≤0.02MPa is considered qualified) | 1. Direct disassembly of components at high temperature is prohibited; control the cooling rate at ≤50℃/h to prevent equipment cracking due to excessive temperature difference; 2. After the air tightness test is qualified, run the equipment without load for 1 hour to confirm no leakage before putting it into production |
| Cleanliness Requirements for Pharmaceutical/Food Industries | 1. After each maintenance, disinfect the inside of the heat exchanger (heat exchange tubes, shell side) (use food-grade disinfectants such as peracetic acid solution); 2. Rinse thoroughly with purified water after disinfection and put into use after drying; 3. Establish a maintenance record file to record the time, operator, and test results of each maintenance and disinfection for traceability | 1. Control the disinfection temperature at 60~80℃ and the disinfection time for ≥30 minutes to ensure thorough disinfection; 2. Maintain records should be kept for at least 1 year to meet the certification requirements of GMP in the pharmaceutical industry and HACCP in the food industry |
IV. Maintenance Safety Specifications
- Personal Protection: Wear high-temperature resistant gloves and goggles for all maintenance operations; when entering the interior of the equipment (e.g., cleaning heat exchange tubes), fasten a safety rope and have a dedicated person monitor the process.
- Shutdown and Cooling: Before maintenance, shut down the equipment and wait until the shell temperature drops to ≤40℃ and the internal temperature drops to ≤80℃ before operation; disassembly of components at high temperature is prohibited.
- Tools and Agents: Tools used should be marked as "Heat Exchanger-Specific" to avoid component damage caused by mixed use; cleaning agents, descaling agents, and disinfectants selected must meet industry standards (e.g., food-grade, pharmaceutical-grade) and provide product qualification certificates.
- Emergency Handling: In case of burns or equipment damage during maintenance, immediately stop operation and contact the safety management department or equipment manufacturer's technical personnel for handling; unauthorized and non-compliant handling is prohibited.
V. After-Sales Support and Services
If you encounter technical difficulties during maintenance (e.g., heat exchange tube repair welding, fan calibration) or need customized industry-specific maintenance solutions (e.g., dust-proof maintenance in the lithium battery industry), you can contact Hangzhou Thermal Engineering Technology Co., Ltd. for professional support:
- Technical Consultation Hotline: 86-571-86722520
- After-Sales Email: rosiedong@hzredong.com
- Company Address: Room 605, 6th Floor, Building 2, Dongzhan Garden Business Center, No. 768 Huanshan East Road, Jianqiao Street, Shangcheng District, Hangzhou City, Zhejiang Province
We provide "1-hour response and 24-hour technical guidance" services to help your industrial high-temperature resistant heat exchangers operate stably for a long time and ensure the efficient output of the hot air furnace system.
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Contact: Rosie
FAX: +86-571-86726270
Room 605, 6th Floor, Building 2, East Station Garden Business Center, Shangcheng District, Hangzhou City, Zhejiang Province