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Online monitoring and early warning for leaks at high-risk, easily leaky sealing points: There are blind spots in leak detection at high locations such as the top of towers and tanks, as well as at inaccessible sealing points beneath insulation layers. Even if the sealing points under conditions of alternating high and low temperatures or high temperature and high pressure are tightened to a specified torque and pass the airtightness test, they may still leak over time due to high-temperature creep, stress relaxation, or aging of the sealing materials when operating under such conditions. High-risk, leak-prone, and inaccessible sealing points pose leakage safety hazards. High-risk, leak-prone, and inaccessible sealing points account for approximately 0.5 – 5‰ of the total number of sealing points in refining and chemical processing facilities. However, since their condition or leakage status remains unknown over time, it is difficult to detect them; just as a large dam can be destroyed by tiny holes, the damage caused by leaks from such points is often several times or even dozens of times greater than that caused by accessible sealing points. If leaks at high-risk, prone-to-leakage sealing points are not detected in a timely manner, minor leaks can develop into significant or severe leaks, resulting in partial shutdowns of the refining and processing units for repairs or unplanned shutdowns ； If obvious or severe leaks are not addressed in a timely manner, or if emergency response measures are inadequate, it may also lead to safety production accidents. A high-risk leakage-prone seal point monitoring and early warning system that focuses on the most critical seals; it provides continuous online monitoring of the health status of these seals and of any leakage trends. Early detection of leaks: it is able to identify which seal is leaking at what time, what substance is leaking, and uses AI to assess the risk level of each seal’s leakage, thereby sending out warning alerts ； Prevention before it happens: It enables the monitoring and prevention of leakage risks and incidents at their source, facilitates predictive maintenance of the sealing points in critical equipment, improves the reliability, utilization rate, and productivity of such equipment, enhances the intrinsic safety level of refining and processing units, and ensures smooth operation of these units. Online monitoring and early warning systems for leaks at high-risk, prone-to-leak sealing points have been widely applied in facilities for styrene production, hydrocracking, ethylene cracking, continuous reforming, butadiene production, and adsorption desulfurization. Typical success case of an IoT system for online monitoring and early warning of seal point leaks: A large petrochemical company identified over 200 high-risk, prone-to-leak seal points in its aromatic reformation and ethylene cracking units, and installed an IoT system for online monitoring and early warning of leaks. Less than 2 months after the system was put into operation, the sealing points at the top of a certain fractionation tower, which had been tightened to the specified torque and passed the airtightness tests, began to leak; measurements taken by the third-party testing agency LDAR showed that the leakage level was above 200 PPMMV ； 2–3 weeks later, on-site LDAR measurements showed leak levels exceeding 2000 PPMV. Starting from week 4, the online monitor showed excessive readings, with the LDAR measurements indicating leakage levels of over 15,000 PPMV. On-site observation revealed obvious dripping at the outlet of the leak detection tube connected to the online monitor, with an average of 2–3 drops per minute. Three years after the system was put into operation, a total of 7 leakage points exceeding the limits were detected ； Four of these leakage points were classified by the online monitoring IoT system as high-risk red leakage sites, with the measured leakage levels according to the data tags exceeding 15,000 PPMV; on-site observation revealed obvious liquid droplets or continuous dripping at the outlet of the leak detection tube connected to the monitoring device. Of the 7 leakage points found to be exceeding the specified limits, 4 of those with excessive leakage were subjected to predictive maintenance using constant-torque thermal fastening technology; after repair, they no longer leaked. The Internet of Things system for online leakage monitoring classified them as leakage-free sealing points (blue) ； Two seal points with excessive leakage continued to leak after predictive maintenance; the IoT system for online leakage monitoring classified them as yellow-level leakage seal points with low risk ； One seal point with excessive leakage continued to show dripping after being heat-tightened; the online leakage monitoring IoT system classified it as an orange-level seal point with medium to high risk, requiring close attention and regular inspections during the operation of the device. Investment returns of the Internet of Things system for online monitoring and early warning of leaks at sealing points: Based on the Heinrich’s Law and Sinopec’s safety risk matrix, every 100 potential safety hazards can lead to 30 recordable near-miss incidents (Grade A hazards); every 30 such near-misses can result in 2.9 minor accidents (such as injuries or partial plant shutdowns, Grade B hazards) and 0.1 major accidents (such as serious injuries or fatalities, Grade C, D, or higher level hazards). The cost for carrying out one local shutdown to rectify issues at high-risk sealing points (Level B hazard) is 100,000 to 500,000 yuan. In aromatic plants or ethylene plants, there are usually over 100 high-risk, leak-prone, and hard-to-reach sealing points. Based on an estimate of 100 potential leakage points, once the online monitoring and early warning system for leakage at these points is put into operation, it can prevent annual losses associated with emergency repairs while the system is still under pressure or with partial shutdowns to address the issues, amounting to (100,000 – 500,000 yuan) * 2.9 = 290,000 – 1,450,000 yuan per year ； Or avoid the situation where (10+50)/2 = 300,000 * 2.9 = 870,000 per year in terms of property losses resulting from emergency responses after a leak. Assume that 1.48 million yuan is invested (including costs for design, installation, operation, and maintenance) to carry out online, continuous monitoring of the condition of 100 leakage-risk points; the lifespan of the monitoring equipment is at least 4–5 years (one major maintenance cycle) ； Therefore, by investing in an online monitoring and early warning system for seal point leaks, the total static investment return after 4 years of operation would be 870,000 yuan/year * 4 years – 1.48 million yuan = 2 million yuan, resulting in an average annual static investment return of 500,000 yuan/year. Conclusion: Investing in a leakage online monitoring and early warning system to continuously monitor the health status and leakage trends of 100 potential leakage risk points online can essentially recover the entire investment cost within 2 years.