Page 168 - Sustainability in the Process Industry Integration and Optimization

Fu r t h e r A p p l i c a t i o n s o f P r o c e s s I n t e g r a t i o n 145

Start

Plan preventive maintenance
interval and tasks to maximize
process availability while
Process meeting risk criteria
Synthesis Stage

Reliability and Risk
Analysis

Is the life cycle cost No
minimized?

Yes

A process with the best life cycle cost

FIGURE 6.20 New process design methodology with integrated RAM stage.

methodology incorporates the simultaneous consideration of flexible
process design and reliability, and optimal solutions are obtained by
Process Integration.
To integrate RAM into process conceptual design, the optimal
preventive maintenance (PM) interval must be embedded into the
superstructure. The superstructure accommodates a number of
different designs, each with a different operating mode. Each so-
called available design is linked to its associated financial penalty
through its asset usage during the design’s life cycle, which is
calculated as the ratio of real throughput to ideal throughput. This
ratio is equal to the sum of the availability across all operating modes.
Thus, Yin et al. (2009) defined the superstructure system availability
(SSA) as

SSA Real throughput ¦¦ Ax (6.6)
ii
Ideal throughput
j i