What should be taken into consideration during the first major shutdown for aromatic extraction? Which areas need to be inspected carefully?
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What should be taken into consideration during the first major shutdown for aromatic extraction? What are the key points? It would be great to have a maintenance plan to refer to! Thank you. Currently, the defoamer pump in my system tends to get clogged frequently – (the silicone oil is not mixed evenly and accumulates at the bottom of the defoamer tank). Is there any good way to solve this problem?
Be aware of the spontaneous combustion of ferrous sulfide in the solvent system. Generally, it is pressurized with nitrogen and purged with steam. Isolation with blind flanges. Ensure airtightness of the vacuum system in the recovery tower. Before shutting down, check whether the sealed valves are functioning properly and replace them in a timely manner; otherwise, it will affect the shutdown process. The main issue with foam suppressant pumps is that the pipelines near the solvent tend to get clogged. Add heat tracing.
Is there a difference between defoamers made from silicone oil formulated with toluene and those formulated with mixed aromatics? I switched my formulation to a mixed aromatic compound, and it still manages to prevent foaming in the stripping tower; it seems that the solubility of silicon oil isn’t very good?
After the aromatic extraction unit stops operating, the wastewater from washing has a high COD level, making it difficult to treat; therefore, a disposal plan must be considered in advance, and a dedicated tank is required for storage； The steam purging process involves solvents, which results in a strong unpleasant odor at the site; therefore, operators must be equipped with masks that protect them from benzene and other solvents, to ensure their occupational health ； The defoamer can be added directly through a top vent in the solvent regeneration system, as long as its amount is kept stable.