Oil and gas platforms with steam bottoming cycles: System integration and thermoenvironomic evaluation

The integration of steam bottoming cycles on oil and gas platforms is currently regarded as the most promising option for improving the performance of these energy-intensive systems. In this paper, a North Sea platform is taken as case study, and a systematic analysis of its energy requirements is conducted. The site-scale integration of steam networks is evaluated, based on thermodynamic, economic and environmental performance indicators. The penalties induced by operational restrictions such as (i) the use of a heat transfer loop, (ii) the demand for a heat buffer, (iii) the selection of a specific cooling utility, and (iv) the weight limitations on the platform are quantitatively assessed. The results illustrate the benefits of converting the gas turbine process into a combined cycle, since the fuel gas consumption and the total CO2-emissions can be reduced by more than 15%. Using the cooling water from the processing plant reveals to be more profitable than using seawater, as the additional pumping power outweighs the benefit of using a cooling medium at a temperature of about 8 °C lower. This study highlights thereby the importance of analysing energy savings and recovery options at the scale of the entire platform, rather than at the level of the utility plant solely.