(119b) Integrating Reliability, Availability & Maintainability into Process Design

Integrating Reliability, Availability & Maintainability (RAM) analysis into process design makes it a powerful tool for equipment selection during the design phase of the project. The traditional method for making equipment choices in the conceptual phase is experience based. The plant availability is generally assumed (usually 80-95%) based on similar installations at the beginning of the design phase. A RAM study is generally performed only to validate the assumptions from the beginning of the project.

 This paper presents a unique approach of using simplified RAM models combined with economic analysis of a range of potential market factors to make process engineering choices at the design phase of the project. The RAM analysis results can be straightforward, but become more complex when combined with economic analysis of input parameters that are not discrete values and are driven by market factors. This paper presents a simple case study for an LNG plant with waste heat recovery vs. fired heaters and how RAM analysis can be used to make an engineering choice.  Several methods for analyzing RAM are available. In a simulation method, a probability distribution is assigned to the “mean time to failure” and the “mean time to repair” and a Monte Carlo simulator is used to dynamically analyze the behavior of the system. A more simplified analytical method uses reliability flow diagrams and simple equations to analyze the RAM. Both methods will be discussed in the case study. While this paper focuses on a single case study, the concepts can be of value across applications.