High-risk pump configuration and operation management

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This post was last edited by shijiazhuang on 2021-4-14 at 11:19. 1 Basic Requirements 1.1 Definition of regulatory content High-risk pumps include high-temperature pumps (those transporting media with an operating temperature ≥ the autoignition point or 260°C), liquid hydrocarbon pumps (those transporting hydrocarbons of C1-C4 type), and pumps for moderately toxic and hazardous media (including benzene, hydrogen sulfide, and other toxic and hazardous substances; for details, refer to HG/T 20660-2017, Classification Standards for Toxicity and Explosive Hazard Levels of Chemical Media in Pressure Vessels). Pumps for toxic and hazardous media generally include aromatic hydrocarbon pumps (pumps used to transport substances with benzene ring structures, such as benzene, toluene, xylene, etc.) and pumps for hydrogen sulfide-containing media (usually referring to acid water pumps and amine-rich liquid pumps). 1.2 High-temperature pumps and liquid hydrocarbon pumps can be considered for inclusion in Class A equipment management. 2 Management Content 2.1 Requirements for the design and selection of high-risk pumps 2.1.1 When upgrading, modifying, or newly constructing high-risk pumps, centrifugal pumps must comply with the requirements of API 610 (SH/T 3139) throughout the processes of design, selection, material selection and manufacturing, as well as inspection and testing. The shaft end mechanical seal should be a cascade or double-face mechanical seal that meets the requirements of API 682 (SH/T 3156), or a dry gas seal suitable for use in pumps. For the selection of liquid hydrocarbon pumps and pumps for toxic and hazardous media, sealless pumps (caged pumps or magnetic drive pumps) can also be chosen in accordance with API 685 (SH/T 3148). 2.1.2 Requirements for seal configuration at high-risk pump shaft ends 2.1.2.1 For high-temperature pumps, Plan32+53A is recommended as the preferred sealing scheme; when site conditions do not permit this, Plan21+53B can also be used. 2.1.2.2 Liquid hydrocarbon pumps: For C1-C3 pumps, the recommended sealing schemes are Plan11+52 or Plan11+72+76; for vertical pumps, Plan14+52 or Plan14+72+76 can be used depending on the circumstances. For the C4 pump sealing scheme, Plan11+52 or Plan11+72+75 (or 76) is recommended. 2.1.2.3 Pumps for toxic and hazardous media: For media containing aromatics, the Plan11+53A sealing scheme is recommended ； For sealing media containing hydrogen sulfide, P1an32+53B (or 53A) is recommended. If there is no suitable flushing source, Plan11 or Plan21 can also be used for the primary seal. 2.1.2.4 For the primary seal of high-temperature pumps, Plan32 and Plan21 can be used ； For sealed back cooling, demineralized water or steam with a pressure not exceeding 0.3 MPa should be used ； Mechanical seal with heat exchanger cooling, using softened water as the cooling medium ； New installations should be equipped with a water softening station; it is strictly prohibited to use recycled water or fresh water to cool mechanical seals and coolers ； For installations without softened water stations, gradual renovation and implementation are required. The temperature of the flushing oil (including self-flushing and external flushing) should be ≤70°C (special cases shall follow the design requirements). 2.1.2.5 The selection of seals and their materials shall be in accordance with API 682 standards (SH/T 3156). The sealed auxiliary sealant tank is required to be equipped with monitoring instruments for pressure, liquid level, temperature, etc. Transmitters are generally recommended for pressure and level display. Pressure and level signals should be transmitted to the control room for real-time monitoring, and incorporated into the regular alarm management system. Each sealing tank in the Plan53A system should be equipped with an independent nitrogen pressure regulator, as well as a fluid replenishment facility capable of operating under pressure. 2.1.2.5 For high-risk pumps, sealless pumps (caged pumps or magnetic drive pumps) should be used. The specific configuration requirements state that the sealless pumps must comply with the API 685 standard; caged pumps shall be equipped with mechanisms for monitoring pump rotation as well as for detecting leaks in the shielding sleeve (or for monitoring the temperature of the shielding sleeve). Graphite bearings should be equipped with bearing wear monitoring. Unsealed pumps must be equipped with a low-load alarm. 2.2 Design requirements for high-risk pumps: 2.2.1 When updating, modifying, or installing high-risk pumps, the design must specify concrete installation requirements. There should also be specific tolerance limits regarding the connection between the inlet/outlet flanges and the pipelines, so as to ensure a stress-free connection. A dedicated person should be assigned to inspect the installation quality and keep records. 2.2.2 For electrical and instrumentation cables in new projects, it should be avoided to run them above high-temperature pumps; for existing cable trays above such pumps that cannot be removed, fire protection measures must be taken. 2.2.3 A shut-off valve shall be installed at the base of the extraction pipeline from the high-risk pump inlet tank, and the distance between the shut-off valve and the pump shall be ≥6m. When the volume of the extraction equipment is greater than 40 m3 and the distance to the pump is less than 15 m, this shut-off valve should be a remotely operated valve with manual operation capabilities. The local operation button of the remotely operated valve should be at a distance of no less than 15 m from the pump, and the DCS should be equipped with shut-off valve functions to enable rapid isolation of the material in emergency situations. 2.2.4 When the diameter of the inlet and outlet valves for high-temperature pumps is ≥DN300, pneumatic or electric valves can be used to facilitate operation, enabling easy shutdown of the material flow in case of an emergency. The distance between the local operation button and the pump should not be less than 6 m. Enterprises with the necessary capabilities can configure the DCS to have shutdown and isolation valve closure functions, enabling rapid shutdown of the motors and interruption of material flow in emergency situations. 2.2.5 A video surveillance system should be installed in the area where high-risk pumps are located. 2.2.6 High-risk pumps should be equipped with an online condition monitoring system, and the condition monitoring setup for newly added high-risk pumps should be completed during the design phase. The signals from vibration and temperature sensing probes must be standardized and compatible with the enterprise’s existing condition monitoring systems. When the pump is operating normally, it is advisable to collect data every 2 hours. When the pump operates abnormally, the data collection frequency should be increased automatically, and the cause should be investigated on-site promptly. Vibration and temperature signals must be fed into the control room, with over-limit alarms and trend alarms set up, and incorporated into the regular alarm management system. 2.2.7 High-risk pumps should be equipped with an oil mist lubrication system (it may be omitted if it is located far away from the operation area or if the conditions do not permit its use); new high-risk pumps must have such a lubrication system installed during the design phase. The bearing temperature of the oil mist lubricator pump should be ≤50°C. 2.2.8 The check valve at the outlet of high-risk pumps should be of the swing type. For pumps with an inlet-to-output pressure difference of ≥4.0 MPa, a double isolation valve and double check valves of different types should be installed at the outlet. Wafer-type check valves are not suitable for use at the outlet of high-risk pumps. In pumps that are at risk of containing particle impurities, solid deposits, or corroded debris, it is advisable to install the inlet and outlet valves on vertical pipes (inform the supplier that the fit between the valve disc and the valve seat must meet the operational requirements) in order to prevent internal leakage of the valve caused by deposits in the valve seat grooves. 2.3 Operation and maintenance management of high-risk pumps 2.3.1 The list of high-risk pumps should be reviewed annually; after approval by the equipment management department, some of them shall be included in the management category of Class A equipment. 2.3.2 Operating procedures for high-risk pumps shall be prepared based on design documents and equipment factory documents. For newly added equipment, the preparation of operating procedures must be completed one month prior to its commissioning. These procedures shall be approved by the responsible department before being issued for implementation, and operator training must also be conducted. 2.3.3 To ensure the stable operation of high-risk pumps and auxiliary facilities, it is necessary to operate them within the specified operating conditions as required by the operating procedures; operating below the minimum allowable flow rate is prohibited. The pump flow sealing system keeps the pressure and liquid level in the isolation fluid tank stable; any abnormal fluctuations must be analyzed for causes and corrected as soon as possible. 2.3.4 Operators should pay attention to the stability and accuracy of relevant parameters such as the pressure and liquid level in the tank drawn by the pump, as well as the outlet pressure of the pump. The instrumentation and control team must implement proper anti-freezing and anti-condensation measures for the relevant instruments to ensure effective protection against freezing and condensation. 2.3.5 Conduct regular inspections. The operator conducts inspections of high-risk pumps every 2 hours, focusing on the maintenance and inspection of the mechanical seal system and bearing lubrication system of these pumps. The seal auxiliary system is the foundation for ensuring seal performance. Operators must check at least once every 4 hours the operating liquid level and pressure in the seal tank, as well as the injection pressure (injection rate) and temperature of the flushing oil and backcooling fluid. The flushing oil filter should be checked regularly to ensure it is in good condition. Detect defects and other abnormal conditions, and address them in a timely manner. For defects that cannot be addressed promptly, preventive measures must be taken in accordance with defect management requirements, and they should be included in the maintenance plan until they are eliminated. 2.3.6 Ensure proper monitoring of the operating condition of pumps. The operators and maintenance staff shall use the instrument at least once per day to measure the horizontal and vertical vibration speeds as well as the temperature of the bearings in high-risk pumps, and keep records of these measurements. For high-risk pumps that are equipped with online condition monitoring systems, the frequency of offline monitoring can be reduced appropriately after a risk assessment, but it must not be less than once every 2 days. Offline monitoring data should be compared with online condition monitoring data. If the deviation exceeds the allowable range, the cause must be investigated and rectified promptly. Managers should regularly compile statistics on online and offline monitoring data on a weekly basis, analyze any abnormal data, and impose evaluations for any violations. It is advisable to install an L-value detector, with the maintenance unit or a specialized condition monitoring department carrying out L-value measurements at a frequency of at least once per day. 2.3.7 When it is found that a high-risk pump is not operating normally, the cause should be investigated immediately, measures should be taken, and a report should be submitted promptly. At the same time, increase the monitoring frequency in light of changes in the pump’s operational process parameters and its operating conditions. 2.3.8 The actuator, bronze sleeve, bearings, and packing of the pump’s inlet and outlet valves should be maintained regularly to ensure smooth operation and no leakage. The valve should be fully open or fully closed. 2.3.9 The instrumentation and control specialty must pay attention to the operating ranges of instrument equipment related to high-risk pumps, and ensure that the measurement ranges of level transmitters and pressure transmitters are appropriate. The selection of control valves must be matched to the flow rate; generally, the opening degree of control valves on the outlet pipelines of high-risk pumps should not be less than 10%. Regularly inspect field instrumentation and circuits, and perform routine maintenance in accordance with preventive measures to ensure the proper operation of the instruments. 2.3.10 The electrical department shall conduct regular inspections of motors used in high-risk pumps. It shall also perform regular oiling and daily maintenance on other electrical equipment such as frequency converters, power cables, and switchgear in accordance with preventive measures, to ensure their proper operation. Operation beyond the rated current is strictly prohibited. Enterprises with the necessary capabilities should monitor current and voltage. 2.3.11 For pumps whose failure rate remains high for an extended period, the cause should be identified as soon as possible; if it cannot be resolved, the pump should be replaced promptly. For high-risk pumps whose pump specifications and materials, sealing arrangements, as well as the electrical and instrumentation cables for the inlet and outlet valves do not meet the requirements of these management regulations, a rectification plan should be formulated, the best solution selected, and implementation carried out at an appropriate time. 2.3.12 It is necessary to verify and mark the fully open and fully closed positions of high-risk pumps and valves; when closing a valve, it must be confirmed accurately through markings or the position of the valve stem before it can be deemed to be fully closed. 2.4 Enhance stable operation 2.4.1 Ensure stable operation of the process. 2.4.1.1 Strictly adhere to process discipline, smoothly adjust process parameters, and prevent cavitation and vacuum formation in high-risk pumps. For pumps that operate at low flow rates for extended periods, energy-saving and efficiency-improving measures such as adding bypass circuits to the impeller and upgrading the entire unit should be adopted. 2.4.2 Ensure smooth pump switching 2.4.2.1 During the switching process, pay attention to fluctuations in current, pressure, and flow rate to ensure a smooth transition. During the switching process of high-risk pumps, measures must be taken to prevent leaks and fires as well as to protect personnel; the operations must be carried out strictly in accordance with the pump switching procedure sheet. 2.5 Maintenance of High-Risk Pumps 2.5.1 Maintenance Strategy for High-Temperature Pumps: Pump maintenance is carried out based on the principle of preventive maintenance as the main approach, with condition-based maintenance serving as a supplementary measure, in order to avoid both under-maintenance and over-maintenance. It is necessary to determine appropriately the maintenance and replacement intervals for the seals of high-risk pumps; when the cumulative operating time of mechanical seals and rolling bearings exceeds 25,000 hours, preventive maintenance should be considered. At the same time, a thorough inspection, maintenance, and cleaning of the seal auxiliary systems should be carried out (chemical cleaning may be employed as appropriate) to ensure that the seal flushing system and cooling system are in good condition. A preventive maintenance plan must be developed in accordance with the requirements of the preventive strategy for high-risk pumps, and the maintenance of such pumps should be carried out based on this plan. When maintaining the pump, the maintenance unit must verify the quality of components such as seals and bearings used. Special tools must be used for bearing disassembly and assembly; direct hitting is strictly prohibited. 2.5.2 After maintenance on high-risk pumps, enhanced care should be taken. Within 72 hours after the equipment is started up, both parties shall jointly carry out trial operation inspections and assess the quality of the maintenance work; if the expected results are not achieved, the reasons must be analyzed. Within 2 hours of starting up the high-temperature pump, vibration and temperature values should generally be recorded every 30 minutes; after 2 hours, these values should be recorded every 4 hours. After 24 hours, if the equipment is operating smoothly, regular maintenance procedures can be resumed. For other high-risk pumps, vibration and temperature values are generally recorded every 30 minutes within the first 2 hours of operation; after 2 hours, if the equipment is running smoothly, regular maintenance procedures can be resumed. 2.5.3 When putting a high-risk pump’s mechanical seal back into service after maintenance, the seal flushing system should be activated first, followed by the introduction of the medium (for example, in the Plan32+53A system, Plan53A should be activated first, then Plan32, and finally the medium is introduced). For the preheating of high-temperature pumps, the mechanical seal flushing oil system should be activated first, followed by opening the preheating valve. The preheating temperature rise ≤ 50°C/hour. Rotate the pump 180° every half hour to prevent leakage of the seal due to excessive temperature rise over a short period (if the pump manufacturer has specific requirements, follow those instructions). After preheating, the temperature difference between the pump body and the pump inlet shall be ≤50°C to ensure that the standby pump is in good condition. Low-temperature pumps shall be operated in accordance with the pump manufacturer’s requirements. 2.5.4 In the event of a failure in high-risk pumps and auxiliary equipment, a root cause analysis should be conducted, and appropriate corrective actions should be taken. 2.6 Strengthening the quality management of spare parts 2.6.1 Enhancing technical evaluation to select suppliers based on their merits. 2.6.1.1 Enterprises should establish evaluation and selection mechanisms for mechanical seal and bearing suppliers and agents, choosing experienced suppliers with high-quality products; framework agreements for procurement are advisable. During the factory acceptance phase, a quality inspection mechanism for mechanical seals and bearings should be established, and professional testing equipment should be provided if necessary. Welding and bearings must come with warranty certificates. 2.6.1.2 Suppliers that experience 2 quality failures within 1 year shall be subject to public reprimand. A supplier exit mechanism needs to be established. 2.6.2 Requirements for spare parts materials. 2.6.2.1 For the mechanical seal friction pairs of high-temperature pumps, high-quality tungsten carbide and antimony-doped graphite materials must be used; recycled tungsten carbide and low-quality graphite materials are strictly prohibited. For the material of the bellows, INCONEL718 should be used in high-temperature pumps; for other high-risk pumps where the medium temperature is below 176°C and corrosion is a concern, 316L or HC-276 can be used. For high-temperature pump rolling bearings, copper retainers should be preferred; the use of non-metallic retainers is strictly prohibited. 2.7 Training and emergency response 2.7.1 Conduct training for high-risk pumps 2.7.1.1 Grassroots units shall formulate training plans for operators on an annual basis and ensure their strict implementation. The training program should be closely aligned with the actual work needs of operators to ensure targeted training. The training materials are concise and clear, minimizing the risk of misunderstandings. Operators must be proficient in skills such as the proper operation of pumps, switching between pumps in case of failures, status monitoring, valve operation, determining whether valves are in the correct position, calibrating valve actuators, and handling emergency situations on site. It is necessary to be clear about the tasks and key points of condition monitoring, as well as to understand the importance of over-limit alarms and trend alarms in condition monitoring. 2.7.1.2 On this basis, training is provided on the basic structure, working principle of high-risk pumps, as well as knowledge related to impeller bearings and mechanical seals. Operators must be familiar with the daily maintenance methods for high-risk pumps and associated equipment, understand the structure and working principles of valve bodies and actuators, and know how to maintain valves. Share experiences in analyzing typical daily faults. 2.7.1.3 The Human Resources department and the Equipment Management department shall regularly check the implementation of training on equipment-related knowledge, while the operation departments shall regularly assess the skill levels of operators; those who do not meet the standards shall be subject to evaluation. 2.7.2 Improve the content of emergency response plans and the arrangements for drills. 2.7.2.1 Each enterprise shall develop emergency response plans for high-risk pumps, including dedicated sections for incidents such as leaks from these pumps, fires, releases of toxic or hazardous substances, and injuries to personnel, specifying the procedures to be followed in such situations. The plan should be concise and clear, to avoid any misunderstandings. The plan should be reviewed regularly and implemented after approval by the responsible department. 2.7.2.2 Drills for shutting down pumps and making switches shall be conducted semi-annually; the contents of these drills include, but are not limited to, normal operation, fault handling, and status monitoring. It is necessary to fully recognize the differences between failover and normal switching. Faulty operations include, but are not limited to, pump leakage during operation and shutdown due to the pump’s operating conditions exceeding specified limits. Condition monitoring operations include vibration measurement of pumps, temperature measurement, and inspection of operational status. 2.7.2.3 Practical drills on opening, closing, adjusting valves that are subject to operation, as well as testing for internal leakage in the pump outlet check valves, are carried out every six months (including the operation methods; for valves equipped with actuators, it is necessary to determine whether the valve has been opened or closed by checking the position of the valve stem; and ensuring that the valve disc does not get stuck after it has been opened or closed), in order to ensure accurate and effective response in emergency situations. 2.7.3 High-risk pumps should be equipped with automatic fire extinguishing systems. Enterprises that meet the requirements can install fire protection facilities such as smoke detectors and automatic sprinklers in high-risk pump areas to extinguish fires as quickly as possible.