I. General Provisions

1. These specifications apply to the operation and management of rotary drum dryers used in fertilizer production.
2. Operators must undergo professional training, be familiar with the equipment structure, performance, and operating procedures, and pass assessment before taking up the post.
3. Operators should wear work clothes, protective gloves, protective masks, and other labor protection articles. During operation, it is strictly prohibited to wear gloves to touch rotating parts.
4. During equipment operation, operators must not leave their posts; personnel are strictly prohibited from approaching the rotating parts of the drum, and it is prohibited to reach out to clean or touch rotating parts.
5. The dryer should be equipped with dry powder fire extinguishers, and the fire extinguishers should be within their valid period.

II. Pre-Production Preparation Stage

(I) Raw Material Preparation

1. Ensure that the particle size and moisture of the fertilizer to be dried are uniform. Granular fertilizer needs to be screened to remove large impurities to avoid equipment jamming.
2. High-moisture materials need to be dewatered in advance to the range required by the process to prevent wall sticking.

(II) Equipment Inspection

1. Mechanical inspection: Comprehensively inspect the whole machine, drum, support rollers, thrust rollers, transmission gears, motor, and reducer to ensure there is no looseness, abnormal noise, or obvious wear. Check whether the lifting plates (flights) in the drying drum are firm, without looseness or deformation.
2. Seal inspection: Check the sealing performance of sealing parts and feed/discharge interfaces to avoid air leakage and material leakage.
3. Heat source system inspection: Check the fuel supply of the hot air furnace (coal/gas) and whether air duct valves are normal; check whether the induced draft fan and dust removal equipment are normal.
4. Control system inspection: Confirm that temperature control instruments, circuits, and oil lines are all normal and that lubricating oil is sufficient. Set a reasonable hot air temperature; calibrate temperature sensors and moisture detectors.
5. Cleaning inspection: Clean foreign objects and residual material inside the drum to prevent hard objects from entering and causing equipment wear or blockage.
6. Safety protection inspection: Check whether safety guards and guardrails for transmission parts (belts, chains, gears, etc.) are complete and effective.
7. No-load manual barring: First perform no-load manual barring to confirm that the drum rotates smoothly without jamming or scraping.

(III) Trial Run (After New Installation or Major Overhaul)

1. The installed dryer should undergo a no-load trial run of no less than 4 hours.
2. Abnormal conditions during the trial run should be handled in time.
3. After the trial run, retighten all connecting bolts, inspect and replenish lubricating oil.
4. Load trial run may be carried out only after normal trial run. Before load trial run, each auxiliary equipment should undergo individual no-load trial run.
5. After successful individual trial runs, proceed to combined trial run.

(IV) Lubrication Preparation

1. Lubricants shall be used as specified. When substitutes are used, they must meet the specified oil quality and performance requirements. Mixing oil and grease is not allowed.
2. For a new dryer, after continuous operation for 400–500 h, after gear running-in, all oil should be drained out. Clean the oil sump and replace with new oil. Thereafter, the reducer oil should be replaced every 6 months. The oil at the pinion and girth gear should be replaced every 3 months.
3. The amount of oil added to the reducer should be based on the high-speed large gear being immersed in oil to a depth of 1–3 times the full tooth height.
4. Check the oil level once per shift. If the oil level drops to the lower limit of the oil level indicator scale, immediately add oil to the upper limit of the oil level indicator.
5. If oil leakage is found, measures should be taken immediately to eliminate the cause of leakage. Oil leakage is not allowed to flow onto the foundation and corrode it.

III. During Production Operation

(I) Startup Operation

1. Startup sequence: First start auxiliary equipment such as the induced draft fan and dust removal equipment, then start the drum drive motor, and finally raise the temperature slowly. It is prohibited to start directly at high temperature with material.
2. No-load operation: Run the equipment without load for 3–5 minutes and observe whether speed, vibration, and noise are normal.
3. Drum preheating: Ignite the hot air furnace to preheat the dryer, and at the same time start rotating the dryer—heating without rotating the drum is prohibited to prevent drum bending. The hot air furnace should also have a preheating process; suddenly firing at full blast is prohibited to prevent local overheating causing uneven thermal expansion and damage.
4. Gradually feed: According to preheating conditions, gradually add wet material into the drying drum. According to the moisture content of discharged material, gradually increase feed rate.

(II) Normal Operation

1. Uniform feeding: Feed continuously at a constant speed. Do not feed intermittently or suddenly increase feed; avoid blockage, material backflow, and material accumulation that is not dried through. Do not operate under overload for a long time.
2. Temperature control: Adjust hot air temperature according to material type and moisture content. For high-moisture and sticky materials, appropriately reduce rotation speed and extend drying time. Closely monitor temperature changes at the feed and discharge ends.
3. Operation monitoring:
   • Check the dryness/wetness, color, and shape of the discharged material at any time, and promptly fine-tune temperature, feed rate, and rotation speed.
   • Pay attention to machine body vibration, bearing temperature, belt tightness, and fan air pressure.
   • Listen for abnormal noise from the motor and transmission parts.
   • Observe the exhaust gas color (normally colorless or light gray).
   • Keep the induced draft system normal and unobstructed, and promptly discharge moisture and waste gas.
4. Handling of abnormal temperature:
   • Sudden rise in outlet temperature: may be due to insufficient feed rate; increase feeding.
   • Sudden drop in outlet temperature: may be due to heat source failure or excessively wet material; stop the machine and troubleshoot.
5. Moisture monitoring: Regularly sample and test the moisture of the finished product. If it exceeds the standard, increase hot air temperature or slow down the conveying speed; if it is too dry, lower the temperature or increase the speed.

(III) Shutdown Operation

1. Normal shutdown:
   • Stop feeding first, continue idle rotation and drying for a period of time, and completely discharge residual material in the drum.
   • First shut down the heating system (extinguish the hot air furnace), keep the fan and drum running, and allow natural cooling. Shutdown at high temperature is prohibited to prevent drum bending and deformation.
   • After the equipment temperature drops and the material is emptied, shut down the drum motor, induced draft fan, and dust removal equipment in sequence.
   • After work is finished, do not stop immediately; run idly for 3 minutes to completely discharge material in the machine.
2. Long-term shutdown: Cut off the main power and take dust-proof and rust-proof protection measures for the equipment.
3. Handling of sudden power outage:
   • Immediately extinguish the hot air furnace and stop feeding.
   • Every 15 minutes, bar the drum half a turn until the drum cools down.
   • This operation should be assigned to a dedicated person who is seriously responsible; violating this procedure will cause the drum to bend.
4. Handling of material blockage: If material blockage occurs, immediately stop feeding, shut off the heat source, manually clean, and then restart. It is prohibited to reach hands or tools into the drum during operation.

(IV) Operation Safety Precautions

1. During operation, it is strictly prohibited to step over, climb, wipe, reach out to clean, or adjust the equipment. It is strictly prohibited to remove guards to observe rotating parts.
2. When blockage occurs, it is strictly prohibited to put hands into the feed hopper.
3. When drying flammable materials, strictly control temperature, eliminate open flames, and take fire prevention measures.
4. Strictly follow electrical operating procedures and avoid live operation.
5. If abnormal sound, bearing oil temperature rise, etc. occur during operation, stop immediately and inspect.

IV. Maintenance and Care

(I) Daily Maintenance (Each Shift)

1. Cleaning: After each shift, clean residual material inside and outside the equipment to prevent caking and corrosion of the equipment and next blockage. Clean residual material inside the drum and check the wear degree of the lifting plates.
2. Inspection: Check whether all parts operate normally. Pay attention to checking the wear degree of wearing parts.
3. Lubrication: Check whether transmission parts (such as chains, gears, bearings, etc.) are well lubricated; add lubricating oil when necessary.

(II) Regular Maintenance

1. Lubrication maintenance cycle:
   • Regularly lubricate support rollers, thrust rollers, and transmission gears.
   • The injected lubricating oil must be clean, and seals must be good.
   • (Note: For detailed lubrication guidance, see the equipment lubrication nameplate.)
2. Wearing parts inspection and replacement: Regularly inspect support rollers, seals, bearings, sealing gaskets, and other wearing parts, and replace them in time. Severely worn V-belt transmission parts should be replaced in time.
3. Regular calibration: Regularly calibrate errors of pressure gauges and other measuring devices. Calibrate temperature sensors with professional instruments every quarter to ensure temperature control accuracy.
4. Electrical system: Check motor insulation performance every six months. Inspect circuits to eliminate leakage and short-circuit hazards.
5. Rotating parts inspection: Regularly check rotating parts for flexibility and whether there is jamming. Regularly add grease to sprockets and other parts.

(III) Special Maintenance

1. Riding ring and support rollers: Newly installed riding rings are prone to loosening and must be checked frequently. Check the contact between support rollers and supporting riding rings. If support rollers in the same group are not parallel or the line connecting two support rollers is not perpendicular to the drum axis, it will cause excessive force on the thrust rollers and abnormal wear of the support rollers.
2. Transmission gears: If the pinion and girth gear make abnormal noise during operation, check the gear meshing clearance. If the pinion is severely worn, replace it in time. The gear guard should be well sealed to prevent dust entry.
3. Bearings: If bearing oil temperature rises, stop immediately to inspect the cause and eliminate it. Dust and other debris should be removed from the base frame plane of the movable device.
4. Drum: Under working conditions, the support roller frame should be filled with cooling water. Note that solid adhered material in the drum must not be unevenly distributed; otherwise, it can easily cause uneven wear of the riding ring.
5. Motor and reducer: For maintenance, see the motor and reducer operation and maintenance manuals.

(IV) Regular Overhaul

Every six months to one year, professional maintenance personnel should be hired to carry out comprehensive maintenance and inspection of the equipment, including evaluating overall equipment performance, checking whether the equipment meets production requirements, and performing technical upgrades or part replacement when necessary.

V. Common Faults and Remedies