Employing geothermal heat exchanger in natural gas pressure drop station in order to decrease fuel consumption

Natural gas stream must be preheated before pressure reduction takes place at natural gas pressure drop station (CGS). It ensures that the natural gas stream remains above hydrate-formation zone. The heater which is employed to provide the required heat consumes a huge amount of fuel. In this work, the conventional configuration of the natural gas pressure drop station is amended by taking advantage of geothermal energy to provide either all (if applicable) or a considerable portion of the required heat. To evaluate the proposed system in terms of economic and thermal efficiency, Gonbad Kavoos station has been chosen as a case study. Comprehensive thermo-economic analysis has been carried out on the proposed system. The results show that a system comprising 8 boreholes with 150 m depth and 0.15 m diameter each is the most efficient configuration for Gonbad Kavoos station. The achievable providence for the case study was calculated by technical correlations over the standard life time of geothermal systems. Comparison between the proposed system and the previous studied systems proved that the current configuration outperforms all the prior propounded configurations, with IRR (internal rate of return) = 0.155. (C) 2015 Elsevier Ltd. All rights reserved.