Ammonia is an essential nutrient for global food production brought to farmers by a well‐established supply chain. This article introduces a supply chain optimization framework which incorporates new renewable ammonia plants into the conventional ammonia supply chain. Both economic and environmental objectives are considered. The framework is then applied to two separate case studies analyzing the supply chains of Minnesota and Iowa, respectively. The base case results present an expected trade‐off between cost, which favors purchasing ammonia from conventional plants, and emissions, which favor building distributed renewable ammonia plants. Further analysis of this trade‐off shows that a carbon tax above $25/t will reduce emissions in the optimal supply chain through building large renewable plants. The importance of scale is emphasized through a Monte Carlo sensitivity analysis, as the largest scale renewable plants are selected most often in the optimal supply chain. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4390–4402, 2017

The time-varying operation of chemical plants offers economic advantages, particularly in the presence of time-sensitive electricity markets and renewable energy generation. However, the uncertainty and short time scale variability associated with renewable energy production, as well as the nonconvex process and cost models typically associated with chemical processes, make finding the optimal design of such systems challenging. In this work, we present a new approach to finding the optimal design of systems with time-varying operation, called scheduling-informed design, whereby we determine the optimal operation of many designs and embed the resulting cost correlations into the optimal design problem. We apply this method to a case study of wind-powered ammonia generation and show that it greatly improves the computational tractability of the optimal design problem and predicts with greater accuracy operating costs realized due to uncertainty in forecasting.

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Small-scale renewable-powered ammonia production is more sustainable than the current fossil fuel- and energy-intensive method. The development of lower capital cost absorbent-enhanced ammonia synthesis as well as the concept of modular chemical processes may improve the economic feasibility of such a paradigm. This possibility is investigated through an ammonia supply chain optimization study wherein modular, wind-powered ammonia production based on this new technology can be added to the existing infrastructure. The benefit of modularity is captured via a mass production exponent which reduces per-module capital cost as more are constructed. Case studies for Minnesota and Iowa show first adoption of 8760 t/y modules at conventional ammonia prices of $610/t and $574/t, respectively, which are considerably lower than those required for incorporation of scaled-down Haber–Bosch. For mass production exponents of 0.9 and less, modular production results in lower supply chain cost and more renewable incorporation than its continuous counterpart.

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This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

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