Maintaining a neutral water balance in a 450 MWe NGCC-CCS power system with post-combustion carbon dioxide capture aimed at offshore operation

A post-combustion CO2 capture process intended for offshore operations has been designed and optimised for integration with a natural gas-fired power plant on board a floating structure developed by the Norway-based company Sevan Marine ASA-designated Sevan GTW (gas-to-wire). The concept is constrained by the structure of the floater carrying a SIEMENS modular power system rated at 450 MWe. with a capture rate of 90% and CO2 compression (1.47 Mtpa) for pipeline pressure at 12 MPa. A net efficiency of 45% (based on a lower heating value) is estimated for the system with CO2 capture, thus suggesting that the post-combustion CO2 capture system is accountable for a fuel penalty of nine percentage points. The rationale behind the technology selection is the urgency of replacing the dispersed aeroderivative gas turbines which power the offshore oil and gas production units in Norwegian waters with near-zero emission power. As (inherently) fresh water usually constitutes a limiting factor in sea operations, efforts are made to obtain a neutral water balance to obtain an optimal design. This is primarily achieved by controlling the cleaned flue gas temperature at the top of the absorber column. (C) 2010 Elsevier Ltd. All rights reserved.