Blending hydrogen into existing natural gas pipeline distribution networks is becoming prominent in the alternative energy industry. Non-uniformity of the hydrogen concentration can occur in the blends delivered at the demand locations of these networks. The non-uniformity can significantly reduce the total hydrogen blending capacity of the whole network due to concentration limitations of industrial and household equipment or materials. Thus, maximizing hydrogen uniformity can become a necessity in the modeling and design of some hydrogen blended natural gas distribution networks where multiple supplies exist but hydrogen can’t be injected at each supply site.
This paper introduces a methodology to optimize blended hydrogen uniformity. The methodology is illustrated using a hypothetical natural gas distribution network. A natural gas supply tracing study is conducted to establish the order of priority of the supply sources in a demand area. A hydrogen and natural gas blending and parametric study is then carried out to determine a ranking for priority selection of the hydrogen injection sites. Subsequently, an operational optimization study is performed to minimize the number of hydrogen injection sites and maximize the volume of the hydrogen injected.
Using the hypothetical natural gas distribution network, a cost and benefit analysis is performed. The relationship between the total costs and the total hydrogen injection flow rates, as a function of the number of hydrogen injection sites, are tabled and plotted.