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This procedure for commissioning a large chemical complex can help reduce the time required and minimize expenses.
THE COMMISSIONING OF A LARGE PETROchemical complex consisting of multiple process plants is an expensive operation, typically costing between 2% and 5% of the total project cost. This article outlines a systematic approach that can help minimize these costs. It identifies the factors contributing to high commissioning costs and recommends measures to deal with them. This approach also provides insights into critical design data for various equipment and the optimum construction and commissioning schedules of different units. Taking appropriate measures from the earliest stages of the project can help further reign in costs and shorten the project implementation period. These measures essentially aim at maximizing efficiency of utilization of time and materials, which are the main factors contributing to high commissioning costs.
Form a commissioning team and define its functions
The first step toward minimizing commissioning costs is to select a small team consisting of key personnel who will be responsible for commissioning the plants and for their regular operation. This should be done before the basic engineering package (BEP) and the process and instrumentation diagrams (P&IDs) are finalized.
The team should prepare detailed pre-commissioning and commissioning procedures based on the guidelines provided by the technology licensors in the BEP and in the detailed engineering document furnished by the engineering contractor. Then it will review these procedures with the licensor's commissioning experts before finalizing them.
Well-defined and reliably verifiable criteria to judge satisfactory completion of each of the activities performed during the pre-commissioning and commissioning phases of the project must be developed. This will ensure that each activity is performed correctly and that it will not need to be repeated later. The criteria should account for the following:
* line flushing and/or cleaning, drying and filling with inert gas
* checking for leaks in pressure and vacuum equipment
* checking the integrity of isolation systems, pressure-relief systems, valves, etc.
* checking indicating/measuring instruments whose rectification involves shutdown of part or all of the plant.
The team must critically examine the P&IDs from the viewpoint of speedy and satisfactory implementation of the pre-commissioning and commissioning tasks listed above, as well as for trouble-free operations like section-wise commissioning, and...