Multiperiod optimization of compressor allocation with flexible topology structure for refinery hydrogen network

Abstract

The operational parameters of a refinery hydrogen system fluctuate due to internal and external factors during actual operation. Consequently, multiperiod optimization of refinery hydrogen systems have been widely employed to identify the optimal hydrogen network structure and flow scheduling strategies for each subperiod. However, the topology of the hydrogen network is fixed as a result of the optimization, thereby preventing any modification to the network structure in accordance with fluctuations in different operational conditions. When considering the compressor performance curve, it is essential to consider the margin requirements when designing compressors in order to ensure that they are able to meet the necessary flow rates in a range of operational conditions. This ultimately leads to a suboptimal utilization of the available equipment capacity. In this work, the concept of a flexible topology network is proposed to allow the network, which is designed to enable the network to adapt to different operating environments. A mixed integer nonlinear programming model is developed to describe this flexible network and the constraints of the flow-pressure ratio for the compressor are described using a proxy model. Finally, the GUROBI solver is invoked to solve the model. The case study illustrates that although the method proposed in this paper entails an increase in equipment investment by 22%, it effectively eliminates the issue of compressor inoperability, enhances the utilization of compressor capacity, and reduces compression energy consumption and the associated electricity costs.