کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
172308 | 458531 | 2015 | 14 صفحه PDF | دانلود رایگان |
• Optimisation of a LNG-process including a full cryogenic heat exchanger model.
• The objective function is to minimise compression work.
• Size and weight of the heat exchanger are additional constraints in the optimisation.
• Results compared minimal internal approach temperature (MITA) – formulation.
• Discusses how low MITA value implicitly assumes unrealistic large heat exchangers.
A great deal of effort has been put into improving natural gas liquefaction processes, and a number of new process configurations have been described. Recent literature has identified a need for more realistic heat exchanger models to obtain optimum design and operating conditions that do not compromise safety, or that are unrealistic. Here we describe a concept for finding the design and operating conditions of a single mixed-refrigerant process which gives minimum power consumption under given space or weight constraints. We use a sophisticated heat exchanger modelling framework that takes into account system geometry and resolves the details of the heat exchanger through conservation equations coupled with accurate models of thermo-physical properties. First, we find the feasible region which does not compromise safety with Ledinegg instabilities. We then identify the optimal operating conditions for a specific design within this region, before identifying the process design that requires least power consumption. We illustrate how this differs from a purely thermodynamic optimisation, and discuss our key results.
Journal: Computers & Chemical Engineering - Volume 73, 2 February 2015, Pages 102–115