Supply of conditioned gas to the new power plant: Option study analysis

A new combined heat and power (CHP) plant will be installed on an island about 50 km away from the nearest gas conditioning unit to supply power to the national grid and to the refinery. The CHP will consist of the gas turbine generators (GTG) and hence conditioned gas supply is required. In view of this, several options were studied to install the new gas pipeline from the existing gas conditioning unit to the new power plant. The sources of gas and the required processing facilities (compressor, conditioning unit, metering stations, utilities, etc.) were identified for each option. In order to assess the feasibility of each option, process engineering calculations such as gas rate calculations, phase envelope studies for different gas compositions, pipeline sizing, compressor sizing, flare/blowdown study, radiation and dispersion study, and dynamic safety time study were performed. The proposed options were then evaluated based on several criteria such as the gas availability, quality of gas, gas pressure compatibility, existing system operability, pipeline design and operation, compressor design and operation, flare design and operation, etc. This paper describes the methodology, process engineering calculations, challenges faced, and evaluations in performing the feasibility studies for the design.