Rajab Khalilpour

Optimisation of LNG mixed-refrigerant processes considering operation and design objectives

Abstract This paper presents a systematic analysis of optimisation formulations for the LNG process. It focuses on the construction and testing of eight objective functions with an aim to identify the most appropriate formulation. Four objective functions relate to the operational aspect of the LNG process, while four concentrate on the design aspect. It was found that the most effective operation optimisation objective function is the minimisation of the major operating cost, being compressor power ( W s ). For the design objective functions, the minimisation of Net Present Value (NPV) is favoured where no restriction exists on the area available for LNG plant construction while minimising the objective function ( W s – UA ) is favoured in case where a limit on the plant area is imposed. Finally, a methodology is constructed for using both design and operation objective functions over the life of the LNG plant, considering gas field feed profile.

Efficient configuration/design of solvent-based post-combustion carbon capture

Abstract In this study, we analyze two design configurations for post-combustion carbon capture (PCC) namely inter-stage cooling and split flow. The results show that inter-stage cooling configuration has notable impact on improving PCC performance. It is found that, for a flue gas with 13.0 mol% of CO 2 , and with objective of capturing 90% of CO 2 at purity of 98%, base case configuration imposes a 4.7GJ/ton-CO 2 reboiler duty. This energy burden decreases (about 34.8%) to 3.1 GJ/ton-CO 2 with single-stage cooling configuration. Two-stage-cooling configuration further improves the efficiency but only incrementally. Similarly, split flow design configuration shows considerable improvement in efficiency (3.8GJ/ton-CO 2 vs. 4.7GJ/ton-CO 2 for base case).

Contract selection under uncertainty: LNG buyers’ perspective

Abstract As a result of the expanding global LNG market, contracts are becoming more complex due to significant variations in price formulations, flexibility, duration, lead-time, quality, capacity, commitments, discounts and other terms and conditions. The existence of various uncertainties further complicates the contract selection process. We have presented a 2-stage mixed integer linear programming formalism to select LNG contracts with minimum total procurement cost under uncertain demand and LNG price over the planning horizon.

Effect of feed natural gas conditions on the performance of mixed refrigerant LNG process

Abstract The natural gas wellhead conditions vary over the life of a production well. These variations affect the performance, production and product quality of liquefied natural gas (LNG) plant. This study, through a simulation-based sensitivity analysis, highlights the significance of the effects imparted by the feed natural gas conditions on process performance of a propane precooled mixed refrigerant (C3MR) LNG process. The results show that the specific shaft work and thus OPEX is sensitive to the feed composition, flowrate, and pressure. For instance, as LNG production decreases from its design capacity of 3.0 MTPA to 2.4 MTPA over time, the specific OPEX increases from

Membrane-based carbon capture from flue gas: A review

128/t-LNG to

HEN optimization for efficient retrofitting of coal-fired power plants with post-combustion carbon capture

154/t-LNG.