Rent or set up a few tanks and a pump(s) to facilitate quick chemical cleaning for removal of rust and residual product. The same equipment can be used to facilitate "water runs" of certain sections of plant during recommissioning.
I can't over-emphasize the need for early and comprehensive "risk-based inspection" using the most accurate and sophisticated methods available, such as miniature video cameras, borescopes, ultrasonic guided-wave thickness meters, etc. Don't compromise here. A simple visual inspection isn't enough given the consequences of missing a major defect.
Here are a few aspects to keep in mind:
- Control systems with "unobtainable obsolete components." Before spending a small fortune on old pneumatic systems and distributed control systems, examine what an electronic upgrade would cost.
- Original equipment manufacturer or local machine shops. Once a shop has a unit they will want to restore it to "as new" condition. You probably can't afford that expense and must reach some clear understanding with them before work begins.
- Testing. Relief valves and other devices used on process lines are by now well beyond their retest period. Therefore, getting a mobile test shop on site probably is cost effective.
- Pressure vessel code compliance. Depending on the state in which the plant is located, there might be no wiggle room. However, a very early discussion with the insurance carrier around minimum test requirements is important.
- Old product and intermediaries left in equipment and drain/sewer systems. Handling such materials often is more difficult than necessary. In my experience, contractors engaged to help are understandably but unnecessarily cautious and expensive. The assistance of operations people familiar with the plant and the intermediate materials can make their removal both simple and cheap.
- Stuck valves and low point restrictions in flow. Use an infrared camera to identify these. (See: "Use Thermal Imagery For Process Problems.")
- Fuels and lubricants in inventory. It's common to find growth of algae or generation of mild acids inside the equipment and storage containers. Inspect or change the materials if you suspect any deterioration. Get them analyzed first.
- Protected enclosures. Do not presume liquid vapor phase and volatile corrosion inhibitors have completely thwarted rusting. Before refilling with lubricants, conduct an internal visual inspection.
- Motors and generators. Exposure to the elements often results in difficulty to reestablish sufficient internal resistance to ground. Avoid sending units to a contractor's shop — where control of the restart budget can be lost. Instead, find a local electrical contractor who has heating equipment that can be brought to site. Don't dry windings in electric machinery at temperatures exceeding the rating of its insulation system. In general, keep to a maximum temperature of 194°F or 90°C. Check with the manufacturer for equipment-specific information and recommendations.
- Boilers and fired heaters. Ensure the setting (brickwork, refractory and insulation materials) is thoroughly dry. Use portable heaters where necessary to make certain all refractory materials are dry.
- Safety appliances. Clean and repair, as needed, devices such as safety and relief valves, steam gauge, water column, low-water cutouts and blowdown systems.
- Controls. Inspect and test all, especially the water level control and low-water fuel cutoffs, before operation.
- Burners. Do not fire these until a burner technician has checked them. An explosion could occur if the combustion controls don't function properly.
- Safety warnings. Replace lost and faded notices, etc.
- Large machines. In addition to a thorough visual inspection, take oil samples for comprehensive analysis.
- Visual inspection. Look particularly for galvanic corrosion anywhere dissimilar metal components come into close proximity.
- Maintenance. Keep good records and re-establish your preventive maintenance program based on a risk-based reliability-centered model.
Remember, the key is knowing where the deficiencies are, and then fixing or mitigating them early in the process.
BERNIE PRICE is CEO of Polaris Veritas Inc., a Houston-based consulting group. E-mail him at Polarisver@aol.com.