Methanol-Oil Co-transportation System: Strategic Facility Planning for Multiproduct Pipelines to Maximize Benefits

Shifts in energy consumption patterns and the adoption of cleaner fuels have left multiproduct pipelines operating below their design capacity. Leveraging these existing multiproduct pipelines for methanol-oil co-transportation not only boosts the load factors of underutilized pipelines but also eliminates the need for massive investments in new infrastructure, thereby significantly reducing the costs of long-distance methanol transportation. To maximize the benefits of this co-transportation strategy, this study develops an optimization model for the strategic facility planning of multiproduct pipelines. The proposed model can comprehensively assess the feasibility of batch sequential transportation of methanol and refined oil in pipelines, and determine the optimal locations for methanol injection and delivery points as well as the required storage tank capacities. Furthermore, it addresses pipeline shutdown challenges from centralized methanol injection/delivery by regulating mixture interface positions in shutdown segments, reducing mixed oil costs and enhancing operational stability. A real-world multiproduct pipeline in China is used as a case study to analyze how different methanol injection/delivery point locations and methanol profit levels impact two critical outcomes: the pipeline’s methanol transmission capacity and the layout scheme of methanol storage tanks. It is demonstrated that the maximum methanol delivery capacity under the general scenario can reach 31.68 × 10 4 m 3 . The terminal station contributes the highest proportion of this capacity at 29.5%, confirming its critical role in enhancing methanol transportation capacity. Methanol transmission capacity is strongly influenced by multiple factors, including maximum flow rate limits, the distance between injection and delivery points, and sales profits at delivery points. Maintaining high profits at high-flow-rate stations is conducive to sustaining a relatively high methanol delivery capacity. These findings provide a theoretical foundation and decision-making support for multiproduct pipeline transformation initiatives, validating the economic and technical viability of methanol-oil co-transportation.