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RISKWISE™ risk-based inspection (RBI) planning software

TWI’s RISKWISE™ RBI software was recently applied at Nippon Mitsubishi Oil Company's (NMOC) Negishi Refinery, Japan's largest oil refinery in Yokohama. NMOC was created in the April 1999 merger of Mitsubishi Oil and Nippon Oil.

Working with TLV Ltd, TWI undertook an RBI study on the naphtha hydrotreating unit. The objectives of the study were to optimise equipment inspection plans and identify suitable mitigation measures to reduce the risk of failure. The RISKWISE™ model converts failure likelihood to a remaining life indicator (RLI) which is the basis for an inspection interval.

The results of the NMOC study demonstrated the potential for incremental run length extension after selected equipment modifications. It also highlighted the scope for reduced shutdown inspection effort on a significant number of items, as well as suitable and cost-effective risk mitigation actions.

A senior NMOC spokesperson commented: “The software is very easy to use, so special training is not required. It enabled us to demonstrate the integrity of our plant using an advanced maintenance system. RISKWISE™ addresses not just those damage mechanisms known to be dominant in causing failure but also other damage mechanisms which may become active.”

The key features of RISKWISE™ include its user-friendly implementation process (relative to other RBI systems); its unique reliability-rule based evaluation to derive safe inspection intervals; and its risk mitigation module which allows users to assess a range of risk management actions to meet inspection interval targets.

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