Plant Maintenance and Safety

By Sharath Bobbili | November 17, 2010
Anything that moves in a plant experiences wear and tear and needs upkeep. One critical but often overlooked task is keeping maintenance and safety logs, which will help in identifying equipment failures. Keeping pumps operating successfully for long periods requires careful pump design selection. Proper installation and careful operation is crucial, noting pump operating parameters. Pump performance should be monitored for any performance changes over time. If failure occurs, cause must be determined to prevent recurrence. Pumps that are properly sized, dynamically balanced, sit on stable foundations with good shaft alignment, properly lubricated, operated within the specified specs and regularly checked by maintenance personnel who fix any offbeat performance issues never experience catastrophic failure. Typically a pump that fails twice for a similar issue needs to be examined closely for proper installation and whether it's operating out of its specified efficiency points.

For reactor maintenance, the sediment in the incoming feedstock, if not addressed, will be a major problem as it will reduce the reaction efficiency. The reactor must be examined regularly and proper preventative measures should be taken. Filters, whether for finished goods or for incoming feedstock, must be examined and changed regularly. Improper maintenance will result in sediment seepage either into end product or incoming feedstock. A prime cause of filter failure is tears. Air compressors, regardless of size or model, require some form of periodic maintenance. Compressor maintenance must be done according to hours of operation, not calendar date.

Operating equipment outside of process parameters causes a majority of issues. Heat exchangers are also a critical part of the process and careful consideration has to be given to their operating parameters and preventative maintenance. At minimum, automation devices and instruments should be looked at periodically as part of a maintenance schedule. A common failure point for automation instrumentation is not the actual instrument, but the wiring. Regular checks must be performed to make sure the wiring is intact, no process liquids are leaking onto the wiring, and instruments are not experiencing any stresses from the mechanical equipment such as piping and reactors. Also, relief valves must be regularly checked to ensure they are performing according to spec.

Plant safety has to be addressed well before the plant is fully constructed. All safety related points must be identified and proper care should be taken to address each point. All employees should know the plan of action in case of emergency, and a safety document with clearly identified steps needs to be part of employees' vocabulary.

The largest safety hazard in biodiesel plants is methanol and catalyst, which also contains 75 to 80 percent methanol if it's a liquid catalyst. Any equipment that comes in contact with methanol or catalyst needs to be explosion-proof or intrinsically safe. There should be clear demarcation between explosion-proof and nonexplosion-proof areas. Care should be taken to make sure the plant design complies with the latest version of the National Electric Code and all of the National Fire Protection Association codes for flammable liquids and vapors. If for any reason changes to the facility occurred, extreme care should be taken to identify the liquids in the facility and the process/methodology before making any changes. Equipment that is being worked on should be water washed and aired out for days. Methanol leaks due to pump seal, hose and instrumentation connection failures, or similar incidents. Personnel should be trained to be observant for any mechanical abnormalities so remedial action can be taken immediately. A handheld volatile compound detector should be kept handy and employees should be encouraged to use it often to identify any stray vapors in the facility.

Further, it is important to ground the tanks, pumps, panels and instrumentation; regularly check for leaks on the tanks, pumps and pipelines; insulate all heated elements; condensate pumps on the steam line to prevent heat exchange failures; properly install vents and blow-off valves on tanks and process equipment; prevent static hazard while taking samples; use ventilated conditions and all safety measures while doing maintenance work such as welding and cleaning; and ground trucks before loading materials. At the end of the day, one plant accident is one too many.

Author: Sharath Bobbili
Refinery Deployment Project Manager, JatroDiesel Inc.
(937) 847-8050
[email protected]
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