How to handle failures in centrifugal coke oven gas blowers?

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Centrifugal air compressors are high-speed rotating devices commonly used in chemical production. Through rapid rotation, they generate centrifugal force, which causes the gas to flow and expand within the compressor’s impeller. As a result, the velocity and pressure of the gas exiting the impeller increase, thereby achieving air compression. During the operation of centrifugal air compressors, various faults often occur, which affect their performance and impact chemical production. Therefore, this article analyzes the reasons for these faults in centrifugal air compressors, and then proposes effective measures to address them in order to improve the performance of such compressors. Abnormal vibration and noise Q: Misalignment A: Remove the coupling so that the prime mover rotates alone. If there is no abnormal vibration when the prime mover rotates, the fault may be caused by misalignment; check the alignment and refer to the installation instructions. Q: Unbalanced compressor rotor. A: Check the rotor to see if it is caused by dirt or damage; if necessary, rebalance the rotor. Q: Impeller damaged. A: Inspect the impeller and repair or replace it if necessary. Q: Causes of abnormal bearings. A: Inspect the bearings, adjust the clearance, and repair or replace them if necessary. Q: Coupling failure or imbalance. A: Check the balance of the coupling, as well as the bolts and nuts of the coupling. Q: Defective sealing ring. A: Check and measure the gap of the sealing ring; repair or replace it if necessary. Q: Abnormal oil pressure and oil temperature. A: Check the gap of the sealing rings; also examine the oil pressure and temperature at each oil injection point as well as the operation of the oil system, and make adjustments if any abnormalities are found. It should be repaired or replaced when necessary. Q: Dirt and impurities in the oil cause bearing wear. A: Identify the source of the dirt, check the quality of the oil, install filters, change the oil regularly, inspect the bearings, and adjust the clearances. Q: Surge A: Check whether the compressor is operating away from the surge point, whether the surge protection margin is appropriate, and whether the surge prevention device is functioning properly. Q: The stress from the gas pipeline is transmitted to the casing, resulting in misalignment. A: The gas pipeline should be properly secured to prevent excessive stress from being applied to the compressor cylinders; the pipeline must have sufficient elasticity to accommodate thermal expansion. Q: Other devices are operating near the compressor. A: Separate their foundation bases from each other to increase the flexibility of the connection pipes. Thrust bearing failure Q: Excessive axial thrust A: Check the clearance of the thrust bearing, examine the pressure difference at the gas inlets and outlets; if necessary, check whether the clearance of the internal sealing rings is within acceptable limits, as well as whether the clearance of the balance disk sealing rings between sections is within normal ranges. Q: Abnormal lubrication. A: Check the oil pump, oil filter, and oil cooler; check the oil temperature, oil pressure, and oil level; check the quality of the oil. Oil seal ring and seal ring failures, unstable sealing. Q: Misalignment and vibration. A: Refer to the vibration section. Q: Contaminants in the oil. A: Check the oil filter and replace the filter element that is contaminated; improve online filtering. Q: There is a deviation in the seal ring clearance. A: Check the clearance; adjust it or replace it if necessary. Q: Insufficient hydraulic pressure. A: Check the reference air pressure; it must not be below the minimum limit value. Q: The precision of the sealing ring is insufficient. A: Check the sealing ring; it should be repaired or replaced if necessary. Q: The quality of the sealing oil and the oil temperature do not meet the requirements. A: Check the oil quality and temperature, and address the issues. The sealing system does not operate stably or properly. Q: The precision of the sealing ring is insufficient. A: Check the quality of the oil and its temperature, as well as the sealing ring; it should be repaired or replaced if necessary. It will be resolved. Q: The quality of the sealing oil or its temperature does not meet the requirements. A: Check the quality of the sealing oil; if it does not meet the specifications, it should be replaced. Also check the temperature of the sealing oil and adjust it as necessary. Q: The oil and pressure difference system is not working properly. A: Check the reference air pressure and the wiring, and adjust them to the specified values; check the performance of all components in the pressure difference system. Q: The sealing part is worn or damaged. A: Remove the seal, readjust the clearance, and then reassemble; carry out repairs or replacement as specified. Q: The contact wear of the floating ring seat is uneven. A: The contact surface should be ground or corrected, or new spare parts should be replaced. Q: There are notches on the end face of the floating ring seat or the sealing surface is worn. A: Eliminate suction damage and reduce wear; replace with new spare parts if necessary. Q: Seal ring broken or damaged (damage during assembly or caused by thermal stress during idling). A: Damage may occur during assembly, so care should be taken during installation; try to minimize idling operation: it should be replaced if repair is not possible. Q: Sealing surfaces, seals, and O-rings are corroded. A: Analyze the properties of the gas, and replace the material of the components or use new spare parts. Q: The sealed part freezes due to low-temperature operation. A: Remove the ice, or purify the sealed atmosphere with dry nitrogen. Q: Working error of measuring instruments. A: Check the measuring instruments in the system; if inaccuracies are found, repair or replace them if their performance does not meet the requirements. Q: Design errors. A: Examine the original design of the system to check whether the technical parameters meet the requirements; if any issues are found, negotiate with the seller and the manufacturer. Q: Manufacturing error. A: Check the original design and manufacturing process requirements; examine the material quality and processing precision; address any issues found by negotiating with the seller and the manufacturer promptly. Q: Differences in gas properties. A: Check various property parameters of the gas carefully; if there are significant differences from the originally designed gas properties, it will inevitably affect the compressor’s performance metrics. Solutions should be found based on actual needs. Q: Changes in operating conditions A: When the actual operating conditions differ significantly from the design conditions, it will inevitably cause the performance of the compression machine to deviate from its designed performance; if any abnormalities are detected, the cause must be identified. Q: The gap of the sealing ring is too large. A: Check the gaps between various components; if they do not meet the requirements, adjustments or replacements are necessary. Surge Q: The operating point falls within the surge zone or is too close to the surge boundary. A: Check the position of the operating point on the compressor’s characteristic curve; if it is too close to the surge boundary or within the surge zone, the operating conditions should be adjusted promptly to eliminate surge. Q: The anti-surge margin setting is insufficient. A: Determine the anti-surge margin under various operating conditions in advance; the anti-surge margin line should be adjusted to the optimal level. Q: Insufficient intake flow. A: It may be due to insufficient opening of the intake valve, a dirty or frozen valve core, blockages in the intake passage, or a reduced or interrupted supply of air. The cause should be identified and a solution found. Q: The vent valve or return valve does not open in time when operating conditions change. A: When the inlet flow rate decreases or the speed drops, or when the speed rises rapidly, the cause should be identified; the anti-surge vent or return valve should be opened promptly. Q: The pressure in the gas system at the compressor outlet is extremely high. A: When the compressor slows down or stops, the gas is not released or allowed to flow back; the outlet check valve is faulty or not tight, allowing gas to flow in reverse. The cause must be identified and measures taken accordingly. Q: The anti-surge device is not set to automatic mode. A: The anti-surge device should be in automatic mode during normal operation. Q: The anti-surge device or mechanism is not working properly or has failed. A: Regularly check the operation of the anti-surge device; if any failure, imprecision, jamming, or malfunction is detected, it should be addressed promptly. Q: The anti-surge set values are inaccurate. A: Strictly set the anti-surge values and conduct regular tests; if any inaccuracies are found, make corrections promptly. Q: Too rapid acceleration and voltage increase. A: As operating conditions change, acceleration and voltage increase should not be too sudden or fast; they need to occur alternately, in a slow and gradual manner. Q: Speed reduction without first reducing pressure. A: Pressure should be reduced before reducing speed to avoid surge. Q: Changes in the properties of the gas or significant changes in its state can cause damage to compressor components, leading to their detachment. A: Before such changes occur, it is necessary to adjust the characteristic curves; the anti-surge settings should be adjusted based on these altered curves. Damage or detachment of inter-stage seals, balance disk seals, and O-rings can trigger surge phenomena – therefore, these components should be checked regularly to ensure they remain in good condition. Q: The check valve on the compressor’s gas outlet pipeline is not functioning properly. A: The check valve on the compressor’s gas outlet pipeline should be checked regularly to ensure it operates smoothly and reliably, thereby preventing gas from flowing back when the speed drops or the compressor stops. Impeller damage: Q: The material used is of poor quality and lacks sufficient strength. A: Re-examine the materials used in the original design and manufacturing; if the material is unsuitable, the impeller should be replaced. Q: Poor working conditions (reduced strength). A: The working conditions do not meet the requirements; due to the harsh conditions, the strength has decreased. The working conditions should be improved to comply with the design specifications. Q: Excessive load leads to reduced strength. A: Due to excessively high rotational speed, flow rate, or pressure ratio, the strength of the impeller decreases, resulting in damage; operating under severe overload or at excessive speeds is prohibited. Q: Abnormal vibration, with the moving and stationary parts coming into contact with each other. A: Excessive vibration causes the moving parts to come into contact with the stationary parts, leading to damage; it is strictly prohibited to operate the equipment when the vibration level is too high; eliminate the abnormal vibration. Q: Debris enters. A: Debris entering the compressor can damage the impeller or other components; it is strictly prohibited for debris to enter the compressor, so check whether the inlet filter is damaged. Air leakage Q: Deposited inclusions A: Maintain gas purity; deposits in the flow passages and cylinders should be removed as soon as possible. Q: Stress corrosion and chemical corrosion lead to poor performance of the sealing system. A: Prevent stress concentration, stop harmful substances from entering the compressor, and take proper anti-corrosion measures for the compressor. Inspect all components of the sealing system, identify the cause, and resolve it promptly. Q: Defective O-rings. A: Inspect all O-rings; replace those that are defective or worn out. Q: Air leakage from the cylinder or connectors. A: Check the joint surfaces of the cylinders and all flange connections; take action promptly if air leakage is detected. Q: Sealing gel has failed. A: Check the sealing gel and gaskets in the cylinder’s split surface and other areas; replace them if failure is detected. Q: It is not operating properly. A: Check whether the operating parameters are correct, inspect the compressor’s operation status, and address any abnormalities promptly. Q: Damaged, broken, corroded, or worn sealing rings. A: Inspect each sealing ring; if any breakage, damage, wear, or corrosion is found, the cause should be identified and the ring repaired or replaced promptly. Insufficient flow rate and discharge pressure. Q: There is a problem with the flow rate. A: Compare the discharge pressure with the flow rate on the same characteristic curve to determine whether they match, in order to identify the issue. Q: Compressor rotates in the reverse direction. A: Check the rotation direction; it should be consistent with the direction of the arrow on the compressor casing. Q: Low suction pressure. A: Check the inlet filter. Q: The molecular weight does not match. A: Check the actual molecular weight of the gas at the inlet and compare it with the value specified in the manual; if the actual molecular weight is lower than the specified value, the exhaust pressure will be insufficient. Q: The speed of the prime mover is lower than the designed speed. A: Check the operating speed of the compressor and compare it with the specifications in the manual; if the speed is indeed low, the speed of the prime mover should be increased. Q: The circulation volume from the exhaust side to the intake side has increased. A: Check the circulation air volume and the external piping; check the opening degree of the circulation air valve – if it is too large, it needs to be adjusted. Q: Faulty pressure gauge or flow meter. A: Check each measuring instrument; if a problem is found, it should be calibrated, repaired, or replaced. The prime mover is overloaded. Q: The molecular weight is higher than the specified value. A: Check the actual molecular weight of the gas and compare it with the values given in the design specifications. Q: There are electrical problems with the prime mover motor. A: Check the thermal capacity and operating condition of the circuit breaker; check whether the voltage has decreased; verify that the current difference between phases is within 3%; address any issues that are found promptly. Q: Corrosion on the surface of the diffuser adjacent to the impeller, resulting in a reduced diffusion effect. A: Disassemble it for inspection; check each flow channel in the diffuser. If corrosion is present, improve the material used or increase the surface hardness. Clean the surface to make it smooth. If the impeller comes into contact with the diffuser or if the diffuser is deformed, it should be replaced. Q: Deformation of the impeller or diffuser. A: The deformed impeller or diffuser should be repaired or replaced. Q: Contact between rotating and stationary parts. A: Disassemble the prime mover compressor and gearbox; check the clearances in each part and compare them with those specified in the manual; address any issues found promptly. Q: High suction pressure. A: High suction pressure results in an increased mass flow rate and higher power consumption; compare with the design data to identify the cause. And resolve it. During normal operation, centrifugal air compressors can develop faults due to various factors; therefore, it is necessary to strengthen their maintenance and upkeep in daily use, and to regularly inspect all of their components. Centrifugal air compressors are devices commonly used in chemical production, and their safety is crucial for the safety of such production processes. Therefore, it is necessary to strengthen maintenance and management during regular operations in order to reduce the incidence of failures and ensure their safe operation.