AN APPROACH TO EVALUATE THE HEAT EXCHANGER RETROFIT FOR INSTALLED INDUSTRIAL GAS TURBINES: PART II – ECONOMIC EVALUATION

Waleed Al-Busaidi, Pericles Pilidis

Abstract: This is part 2 of the conducted study to develop a new systematic method to evaluate the heat exchanger retrofit on existing industrial gas turbines. A new approach has been introduced and validated in the first part comparing with the measured data. This method was used to optimize the obtained cycle performance characteristics and the generated heat exchanger design options based on technical prospective to attain the highest possible improvement on the simple cycle performance. However, it is essential to consider the economic viability of using the recuperative cycle which will be investigated in thispaper. Although that there are several tools which can be used to achieve that objective, this study uses the Net Present Value (NPV) method due to its simplicity and accuracy. The established technique has been applied for the same described gas turbine cycles in the previous part. Based on the stated assumptions, it was found that by applying the recuperation in the first engine,W6BRC, and at full load and 100% utilization factor conditions, the payback period has increased by one year by applying over that of simple cycle. Moreover, at the end of the project life, the recuperative cycle of this engine is expected to achieve an increase of $11M in the NPV over that of simple cycle. This difference between the two cycles becomes greater in the case of the second engine, W7FA, which is ranging between $33.9M and $46.8M.However, the drop in the availability of the overall recuperative gas turbine by about 18% over the simple cycle gas turbine causes the NPV of both cycles to be equal. Moreover, this paper includes a sensitivity study to investigate the effects of utilization factor and recuperator effectiveness and pressure drop on the cumulative discounted cash flow.

Keywords: new systematic method,economic viability, Net Present Value, utilization factor,availability

DOI: https://doi.org/10.15623/ijret.2015.0408067