Surface oil and gas treatment facilities in .service for decades are likely to be oversized due to the natural depletion of their reserx'oirs. Despite these plants might have been designed modularly, meaning they comprise multiple identical units serving the same task, such units operate often in conditions far from the design. This work analyzes the revamping options of an existing upstream gas facility, cho.^en because representative of a wide set of plants. It presents a flexible process simulation model, implemented in the HYSYS environment and dynamically linked to an Excel spreadsheet, which includes the performance maps of all turbomachineries and the main characteristics of the investigated modifications. The model may be used to run simulations for various gas input conditions and to predict the performance over I year of operation and for different possible future scenarios. The first objective is to assess economically the considered options, which shall be applied only if yielding short return times of the investment since the reservoir is mature. Moreover, all options are appreciated adopting a figure of merit, here defined, that compares the overall energy consumption to the one calculated with .•itate-of-the-art technologies. In addition, exergy and environmental analyses are executed.

Surface oil and gas treatment facilities in service for decades are likely to be oversized due to the natural depletion of their reservoirs. Despite these plants might have been designed modularly, meaning they comprise multiple identical units serving the same task, such units operate often in conditions far from the design point and inefficiently. This work analyzes the revamping options of an existing upstream gas facility, which is chosen because representative of a wide set of plants. A flexible numerical model, implemented in the HYSYS environment and dynamically linked to an Excel spreadsheet, includes the performance maps of all turbo machineries and the main characteristics of the investigated modifications in order to run simulation for many gas input conditions and to predict the performance over a year of operation and for different possible future scenarios. The first objective is to assess economically the considered options, which shall be applied only if yielding short return times of the investment since the reservoir is mature. Moreover, all options are appreciated adopting a figure of merit, here defined, that compares the overall energy consumption to that calculated with state-of-the-art technologies. In addition, an exergy and an environmental analyses are executed.