Supercritical equipment (such as supercritical boilers and supercritical CO₂ extraction units) is characterized by high temperature and high pressure, operating under extremely harsh conditions. Once a fault occurs, it can lead to anything from shutdown and reduced production to tube rupture and leakage, resulting in significant safety risks and economic losses.
Traditional maintenance methods either involve reactive "repair after it breaks down" or "replace when it's due," which wastes the equipment's lifespan. Predictive maintenance is now more practical, relying on intelligent sensors to detect anomalies and issue early warnings before actual equipment failure, allowing for proactive intervention.
To illustrate how this is achieved, let's look at several key monitoring scenarios:
I. Temperature Monitoring: Beware of Tube Rupture Risks Caused by "Overheating"
The heating surfaces of supercritical boilers and the reaction chambers of CO₂ extraction units are constantly exposed to high-temperature and high-pressure environments. Localized overheating accelerates tube wall oxidation and cumulative damage, potentially leading to tube rupture or reduced efficiency. Distributed fiber optic temperature sensors and high-precision thermocouples are commonly used to monitor temperature changes in real time.
The focus is not on individual point temperatures, but on observing the temperature field distribution. For example, a sudden increase of 30°C in pipe wall temperature compared to adjacent areas is a typical anomaly, potentially indicating slagging, pipe blockage, or uneven flow. Early detection can prevent major overhauls.
II. Pressure Monitoring: Detecting Early Signs of Leaks
Leaks in supercritical equipment often take days or even weeks to develop from micro-leaks to noticeable leaks. Intelligent pressure sensors, combined with high-frequency data acquisition, can detect subtle anomalies-for example, under stable operating conditions, a pressure drop of 0.2 MPa every 10 minutes may seem normal on a second-by-second basis, but a clear trend emerges over a 24-hour curve.
If the pressure drop is accompanied by abnormal temperature fluctuations in the corresponding area, the probability of a leak is high. Early warnings allow for planned shutdowns, preventing sudden failures.
III. Vibration Monitoring: Understanding the "Health Signals" of Rotating Machinery
Rotating equipment such as water pumps, fans, and steam turbines are the "heart" of supercritical systems. Vibration sensors, mounted on bearing housings, collect vibration frequency, amplitude, and other data in real time. During normal operation, each piece of equipment has its own unique vibration "pattern." Once bearing wear or rotor imbalance occurs, vibration data will become abnormal.
For example, a factory's vacuum pump once experienced a vibration alarm. Analysis revealed an abnormal frequency, indicating rotor misalignment. Subsequent inspection revealed new abnormal frequencies; disassembly confirmed oil contamination on the rotor and cracked blades. Without warning, the equipment might have been rendered unusable. This logic also applies to auxiliary equipment in supercritical systems.
IV. Flow Monitoring: Identifying Pipeline Blockages or Equipment Efficiency Decreases
Flow meters are not just for measurement; they can also provide early warnings of anomalies. An abnormally decreased flow rate may indicate pipe blockage, valves not fully open, or a need for filter cleaning; an abnormally increased flow rate may indicate internal leaks or pipe ruptures.
The key is to observe the relationship between flow rate, pressure, and temperature. For example, in boiler feedwater pipelines, a decrease in flow rate coupled with an increase in pump current likely indicates pipe scaling or valve jamming, and a check reminder can be issued tens of hours in advance.
V. Chemical Parameter Monitoring: Preventing Invisible Corrosion
The chemical state of boiler water and circulating solvents in CO₂ extraction units directly affects equipment lifespan. Deviations in pH, elevated dissolved oxygen, and excessive chloride ions are all precursors to corrosion. Online chemical sensors can monitor these parameters in real time. For example, if the boiler water pH remains below 9.0 and the corrosion potential is abnormal, it can promptly prompt adjustments to the chemical dosing. Compared to manual sampling and testing, this avoids the problem of discovering corrosion only after it has already occurred.
VI. Acoustic Monitoring: Locating Leaks Through "Auscultation"
Micro-leaks of high-pressure gases and steam are inaudible to the human ear, but ultrasonic sensors can capture high-frequency signals of 20-100kHz. Through spectrum analysis and time-difference localization, leak points can be accurately located with errors controlled within tens of centimeters. This provides significant early warning for early problems such as micro-cracks in furnace welds and flange seal failures.
VII. Complete Early Warning Loop: From Alarm to Inspection and Verification
A complete early warning process should be: sensor detects an anomaly → platform issues an alarm → engineer reviews data and determines the fault type → recommends shutdown for inspection → disassembly and verification → retest after component replacement confirms normal operation. This closed loop ensures that early warning is not merely a formality but truly solves the problem.
In conclusion: Fault early warning for supercritical equipment is no longer a question of "whether to do it," but rather "how to do it more efficiently." By relying on precise sensor monitoring and scientific data analysis, we can shift from reactive maintenance to proactive management, saving not only on repair costs but also on the associated losses in production and safety caused by unplanned downtime.
Of course, this all depends on selecting the right sensors, installing them properly, ensuring data accuracy, and continuously optimizing monitoring methods. This allows equipment to "cry out" in advance, preventing major malfunctions.