Feasibility of ORC application in natural gas compressor stations

Natural gas compressor stations represent a huge potential in terms of waste heat recovery. Typical installations consist of multiple gas turbine units, in mechanical drive arrangement, operated most of the time under part-load conditions. The paper investigates the feasibility of Organic Rankine Cycle application as bottomer recovery technology in natural gas compressor facilities. The aim of the performed analysis is to obtain a detailed techno-economic and environmental scenario of the integrated system on yearly base. Different commercial gas turbine models, in the size range from 3 to 30MW, have been taken into account as representative of mechanical driver units. Bottomer configurations (with & without intermediate loop) are modelled and compared assuming two different organic fluids. A sensitivity analysis of the bottomer cycle is carried out aimed at maximizing ORC shaft power output for each investigated layout. Off-design part-load operation of the integrated cycles have been simulated with reference to one minute data typical GT operation on a yearly base. The goal of this work is: (i) to assess the actual performance of merging gas turbines and ORC units for efficient power generation under variable operating conditions; (ii) to analyze the real potential of state-of-the art technology in the proposed innovative application.