A conceptual method for targeting the maximum purification feed flow rate of hydrogen network

For a hydrogen network with purification, it is postulated that different Purification Feed Flow Rates (PFFRs) will exert different effects on the hydrogen utility consumption. To optimize a hydrogen network with purification reuse, the effect of the PFFR on the hydrogen utility consumption should thus be analyzed systematically. However, no in-depth studies on this subject matter are available in the open literature. This work aims to bridge this research gap by establishing the relationship between the PFFR and the hydrogen utility consumption. According to the concepts of hydrogen surplus and pinch point, the characteristic of the pinch point is analyzed first, and it is found that the pinch point can only appear at the sink-tie-line which can intersect the source purity profile. Then, the quantitative relationship between the hydrogen utility adjustment and the hydrogen surplus is deduced, and a numerical method for identifying the pinch point and the minimum hydrogen utility consumption target is developed. Based on this, the quantitative relationship between the PFFR and the hydrogen surplus at each sink-tie-line is deduced. The upper bound of the PFFR can be identified from the hydrogen surplus variation diagram. The proposed numerical approach for targeting the hydrogen pinch problems and a systematic graphic method for identifying the limiting PFFR have the merit of being conceptually simple and easy to apply. Two cases are studied to illustrate the applicability of the proposed method. ► A numerical method is developed for targeting the minimum hydrogen utility consumption. ► The hydrogen surplus variation diagram is developed. ► The concept of the upper bound of the purification feed flow rate is proposed. ► The procedure for targeting the upper bound is developed.