Synthesis of refinery hydrogen network considering compressor selection and interstage suction/discharge

In refinery hydrogen networks, the optimal arrangement of hydrogen compressors is important to hydrogen reuse and cost reduction. The share of hydrogen compressors can not only reduce the number of compressors, but also provide the economy of scale. However, the previous studies only consider the whole share of compressors and mostly treat the compressor model as reciprocating compressors by default, which limits the optimization of hydrogen networks and does not correspond well with the practice. This paper presents a novel method for hydrogen network synthesis considering the hydrogen compressor type selection and the interstage suction/discharge of multi-stage compressors. In the developed superstructure, hydrogen sources are allowed to be suctioned and discharged via all possible stages of multi-stage compressors. Meanwhile, hydrogen sources can select centrifugal compressors or reciprocating compressors according to the working ranges. A mixed integer nonlinear programming model is developed to minimize the total annualized cost. The proposed method is suitable for both retrofit problems and new design problems, which is demonstrated by a refinery case and a literature case. For the refinery case, the zero-investment retrofit based on the existing compressors can reduce the fresh hydrogen demand by 1.73%, and the new hydrogen network design requires fewer compressors. In terms of the literature case, the hydrogen network design obtained in this paper can reduce the number of compressors by 5 or 3 through interstage suction/discharge of multi-stage compressors.