Effect of Improving Energy Efficiency on System Reliability |
In the present scenario of energy demand overtakingenergy supply top priority is given for energy conservation programs andpolicies. Most of the process plants are operated on continuous basis andconsumes large quantities of energy. Efficient management of process system canlead to energy savings, improved process efficiency, lesser operating andmaintenance cost, and greater environmental safety. Reliability andmaintainability of the system are usually considered at the design stage and isdependent on the system configuration. However, with the growing need forenergy conservation, most of the existing process systems are either modifiedor are in a state of modification with a view for improving energy efficiency.Often these modifications result in a change in system configuration there byaffecting the system reliability. It is important that system modifications for improvingenergy efficiency should not be at the cost of reliability. Any new proposalfor improving the energy efficiency of the process or equipment’s should proveitself to be economically feasible for gaining acceptance for implementation. Inorder to arrive at the economic feasibility of the new proposal, the generaltrend is to compare the benefits that can be derived over the lifetime as wellas the operating and maintenance costs with the investment to be made. Quiteoften it happens that the reliability aspects (or loss due to unavailability)are not taken into consideration. Plant availability is a critical factor forthe economic performance evaluation of any process plant. The focus of thepresent work is to study the effect of system modification for improving energyefficiency on system reliability. A generalized model for the valuation ofprocess system incorporating reliability is developed, which is used as a toolfor the analysis. It can provide an awareness of the potential performanceimprovements of the process system and can be used to arrive at the change inprocess system value resulting from system modification. The model also arrivesat the pay back of the modified system by taking reliability aspects also intoconsideration. It is also used to study the effect of various operatingparameters on system value. The concept of breakeven availability is introducedand an algorithm for allocation of component reliabilities of the modifiedprocess system based on the breakeven system availability is also developed.The model was applied to various industrial situations.