One Question per Day, September 25, 2015

Correct methods (ABC) to prevent the spontaneous formation of ferrous sulfide during shutdown for maintenance

The correct method to prevent the spontaneous formation of ferrous sulfide during shutdown for maintenance (D. Power air purging)

Option D: Power wind sweeping~~~~~~~~~

A. Clean ferrous sulfide using a deodorizer； B. Check whether the temperature of the DCS monitoring equipment is rising. C. Prepare a hose near the manhole;

The correct method to prevent the spontaneous formation of ferrous sulfide during shutdown for maintenance (D) is A. Using a deodorizer to clean ferrous sulfide； B. Check whether the temperature of the DCS monitoring equipment is rising. C. Prepare hoses near the manhole. D. Use compressed air for cleaning. Additional details can be added based on practical experience with various devices.

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The correct method to prevent the spontaneous formation of ferrous sulfide during shutdown for maintenance (D) is A. Using a deodorizer to clean ferrous sulfide； B. Check whether the temperature of the DCS monitoring equipment is rising. C. Prepare a hose near the manhole; D. Use compressed air for cleaning

This post was last edited by ylb913 on 2015-9-25 at 20:42. The correct method to prevent the natural formation of ferrous sulfide during shutdown for maintenance is as follows: 1. Use a \"passivator\" to remove ferrous sulfide, and this should be done after steam purging and the distillation tower has been cleaned. 2. Pay attention to whether the temperature of the DCS monitoring equipment is rising. 3. Prepare a hose at the manhole edge. ——If necessary, we will have firefighters involved in supervision. 4. Emphasize regular inspections or on-site monitoring (for example, in the case of a packed tower, continuously monitor the temperature at various points along the tower wall until all the packing has been removed; if a significant increase in temperature is detected, the people inside must be evacuated immediately, and water should be sprayed to lower the temperature) ； Also, pay attention to whether there is smoke coming from the manholes – these are things we have encountered before), as in some areas the temperature is too high for the temperature sensors to detect it. 5. After purification, before the material enters the cleaning equipment, it is required that the passivation unit remain on site to provide supervision; in case of any issues, water should be used to cool down the material immediately. Additional notes: 1. Power-driven air blowing? In fact, this accelerates air drying in situations where there is a risk of spontaneous combustion of ferrous sulfide, thereby facilitating combustion (we have experienced this on actual occasions; the combustion was not caused by artificial ventilation but by natural wind, which led to the temporary sealing of access holes, followed by the use of steam to extinguish the fire or water to cool it down). ——Although forced ventilation is a common method for removing unpleasant odors from equipment, it is only feasible assuming that there is virtually no risk of spontaneous combustion of ferrous sulfide, or that water is sprayed intermittently while using forced ventilation. 2. Deodorants are used before the distillation tower to reduce unpleasant odors that occur during distillation (which are mainly related to hydrogen sulfide and ammonia); they have nothing to do with removing ferrous sulfide.