Analysis of the Causes of Corrosion in Centrifugal Explosion-Proof Fan Impellers

Analysis of the Causes of Corrosion in Centrifugal Explosion-Proof Fan Impellers

Corrosion of centrifugal explosion-proof fan machinery is a major issue in chemical production. Due to the nature of the specific manufacturing media, equipment is frequently subjected to corrosion from various chemical elements. The primary areas affected are the mechanical components and various pipe fittings, which experience severe corrosion during the hydrogen production process, as well as the centrifugal explosion-proof fans themselves. Impeller. The impeller of the centrifugal fan is exposed to hydrogen sulfide gas, which contains high levels of moisture. As the impeller is made of chromium-nickel alloy, the corrosion has become increasingly severe. The material thickness, originally 3–6 mm, has in some cases thinned to the consistency of paper. Faced with these harsh environmental and operational conditions, we have continued to explore and summarize the following lessons learned. Initially, the surface of the centrifugal explosion-proof fan was coated with 470 resin; however, the results were unsatisfactory under operating conditions. Within a few days, the vibration amplitude of the centrifugal explosion-proof fan reached 10–20 mm/s, causing serious disruptions to production. Based on the process medium, temperature, impeller diameter, and rotational speed of the centrifugal explosion-proof fan, the specific anti-corrosion methods are as follows. 1.1. First, grind the corroded impeller of the centrifugal explosion-proof fan and drill holes in it. 2.2. Apply 901 or 470 resin evenly over the impeller body, then bond the impeller surface and the impeller membrane together using polyester cloth. 3.3. Apply 901 or 470 resin evenly over the polyester cloth again, and bond it using a glass fiber mat. The bonding surface must be flat. 4.4. Apply 984 or 470 resin evenly over the bonded glass fiber mat, and bond it using glass fiber cloth. 5.5. Apply a layer of 984 or 470 resin to the grooves using talcum powder. After performing rust prevention treatment on the centrifugal fan using the above method, allow the applied rust inhibitor to dry completely for 3 to 6 hours (depending on ambient temperature), then reinstall the propeller assembly. At the same time, reinstall the housing of the centrifugal explosion-proof fan. After reinstallation, verify the details and inspect the centrifugal explosion-proof fan. After verification, the dynamic balancing test is divided into online and offline tests. For the online test, ensure the dynamic balancer’s rotational speed probe and vibration probe are correctly installed and connected. Next, calculate the weight and position based on the propeller’s diameter, rotation direction, and the angle indicated by the dynamic balancer. Propellers with diameters less than 1200 mm require an addition of 20–30 g; for diameters between 1200 and 1800 mm, 60–80 g. For diameters over 1800 mm, 90–120 g must be added. The process is considered complete once the vibration value reaches 3–5 mm/s. At this point, the dynamic balancing operation is finished, and the centrifugal explosion-proof fan enters normal operation. The manufacturing and use of centrifugal induction motors have been significantly improved, reducing maintenance and upkeep costs, with a service life of 30–60 days.