Optimization of electrical energy production in offshore installations

The main objective of the project is ?optimization of electrical energy production through efficient measures on existing offshore oil and gas installations in the range 15-20 % and hence thus reduce CO2 emissions to atmosphere?. ? Draugen platform is chosen as the base case for developing solutions for energy efficiency and reducing CO2 emissions. The results can also be applicable for other existing platforms. The following are the main possible solutions for Draugen platform: High temperature ORC for power production gas turbines, Low temperature ORC for gas turbines operation the pumps for water injection, Steam Rankine cycle for waste heat recovery, Heat integration, Smaller compressors for gas compression to reduce re-circulation. ? Several waste heat recovery systems such as Organic Rankine Cycle (ORC), Steam Rankine Cycle (SRC) and Air Bottoming Cycle (ABC) are being studied, analyzed with respect to efficiency, cost, weight and space considerations. Organic Rankine cycle process attains the best performance, with a potential to abate the CO2 emissions and pollutants in the range of 10 - 15 %. In addition, multi-objective analysis is performed to select an optimal working fluid, which is cyclopentane. Further a novel control logic is developed for the combined cycle using model predictive control algorithm to have a stable power system. ? An extensive work is done to understand the energy utilization on the platform and a generic model of energy systems is developed. The model is applied for five different existing platforms (3 platforms in North Sea and one from Brazilian Gulf). The findings from the models show that though the platforms have different operating characteristics, they have similar challenges and opportunities for improving energy efficiency; for example, waste heat recovery, process integration etc. ? A detailed work is done on the control system aspect of the power production for two systems; gas turbines only and gas turbines combined with a bottoming cycle. The work results in developing a control logic and software using model predictive control algorithm which demonstrated better control performance in terms of constraints handling, overshoot and rise time characteristics. ? The project work also performed feasibility analysis for the emerging technologies for their relevance and application on offshore platforms. These technologies include CraftEngine from Viking Heat Engines and HeatPump from Single Phase Power. ? Three PhD projects; 2 at Denmark Technical University and 1 at Carnegie Mellon University are completed within this project ? The project consortium includes 11 partners in total; 2 Research institutes, 2 international universities, one oil and gas producer and 6 technology provider companies. The partners agreed that this has been a successful project where all partners have contributed and benefited from the project.

The main objective of the project is to increase the energy efficiency in the range 15-20% on offshore installations and thus help to reduce the emissions to the atmosphere. There is a potential to increase the electrical energy production efficiency by using advanced control techniques. It is very common to have a decentralized control system for each gas turbine, but not an adaptive supervisory control system for the overall electrical energy production facility at the installation. The project focuses on developing an adaptive supervisory control system for the overall electrical energy production facility. An advanced condition monitoring system for the relevant production facility, which collects critical information from each gas turbine system and provide the necessary information to the control system The flue gases from the gas turbines have considerable sensible energy which can be utilized to eliminate additional heating systems in the platform and further to produce electrical energy from the heat. On the offshore installations with no oil and gas processing systems, the heat in the flue gases from the gas turbines is not utilized. Thus the scope to produce electrical energy production from the energy available in the flue gases is enormous. The most optimal electrical energy production can be achieved by combined optimization of the gas turbine systems and the waste heat recovery systems. The case to establish this system is the Draugen platform and installation. To obtain commercial solutio ns, both advanced technical solutions and make then commercial, research institutes, universities and commercial companies will collaborate.