(33c) Energy Optimization in Natural Gas Processing Plants

Natural-gas processing plants require a series of process units to remove contaminants such as water, carbon dioxide and hydrogen sulphide. These units have various process heating and cooling demands. Adequate matching of the heat recovery requirements can lead to significant operating cost reductions. Excessive heat from process units can be recovered by producing steam, which may be used for satisfying heating requirements of other units or for power generation.

In this paper, novel software design tools with embedded state-of-the-art process integration technologies, i-Heat™ and i-Steam™ are presented for the simulation and optimisation of natural gas processing plants. i-Heat™ is a software tool for the design, evaluation and optimisation of heat recovery systems in industrial processes. The software tool considers realistic industrial constraints leading to the generation of solutions that are both practical and feasible, as well as ensuring the design obtained is optimal. i-Steam™ is a novel software tool to model, simulate and optimise modern steam and power systems. i-Steam™ considers a more comprehensive modelling of the overall utility systems than other software tools, which provides additional degrees of freedom for optimisation.

Systematic procedures for energy optimisation in natural gas processing plants are introduced and discussed. An industrial case study is presented to illustrate the benefits of performance optimisation on the individual processes and the steam system simultaneously by using these novel software. Eleven cost-effective projects were identified by i-Heat™ to save energy consumption in individual process units through enhanced heat recovery. The influence and impact of the individual energy saving projects on the utility system was evaluated effectively with a combined overall process model in i-Steam™. Such a systematic and integrated energy optimisation approach significantly reduced utility consumption and improved the overall economics of the natural processing plant.