| dc.description.abstract |
In the present scenario of energy demand overtaking energy supply top priority is given
for energy conservation programs and policies. Most of the process plants are operated
on continuous basis and consumes large quantities of energy. Efficient management of
process system can lead to energy savings, improved process efficiency, lesser operating
and maintenance cost, and greater environmental safety. Reliability and maintainability
of the system are usually considered at the design stage and is dependent on the system
configuration. However, with the growing need for energy conservation, most of the
existing process systems are either modified or are in a state of modification with a view
for improving energy efficiency. Often these modifications result in a change in system
configuration there by affecting the system reliability. It is important that system
modifications for improving energy efficiency should not be at the cost of reliability. Any
new proposal for improving the energy efficiency of the process or equipments should
prove itself to be economically feasible for gaining acceptance for implementation. In
order to arrive at the economic feasibility of the new proposal, the general trend is to
compare the benefits that can be derived over the lifetime as well as the operating and
maintenance costs with the investment to be made. Quite often it happens that the
reliability aspects (or loss due to unavailability) are not taken into consideration. Plant
availability is a critical factor for the economic performance evaluation of any process
plant.The focus of the present work is to study the effect of system modification for improving
energy efficiency on system reliability. A generalized model for the valuation of process
system incorporating reliability is developed, which is used as a tool for the analysis. It
can provide an awareness of the potential performance improvements of the process
system and can be used to arrive at the change in process system value resulting from
system modification. The model also arrives at the pay back of the modified system by
taking reliability aspects also into consideration. It is also used to study the effect of
various operating parameters on system value. The concept of breakeven availability is
introduced and an algorithm for allocation of component reliabilities of the modified
process system based on the breakeven system availability is also developed. The model
was applied to various industrial situations. |
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