Optimal Design of Sustainable Ammonia-Based Food–Energy–Water Systems with Nitrogen Management

Abstract

As the basis for virtually any form of nitrogen fertilizers, ammonia plays a vital role in agriculture; in addition, there has been an increased interest in its use as a carbon-free energy carrier. However, ammonia is also associated with two major environmental concerns: CO 2 emissions from the conventional production process and nitrogen pollution from the excessive use of ammoniabased fertilizers. To mitigate these environmental impacts, we develop an optimization framework for the design of a sustainable ammonia-based agricultural system that synergistically integrates the production of ammonia from renewable resources and effective measures for nitrogen management. The proposed model captures the effect of intermittency by incorporating both design and detailed operational decisions. By applying a multiscale time representation that reduces the problem size and a tailored surrogate model that accurately approximates model nonlinearity, we are able to achieve optimal solutions within reasonable computation times. A computational case study is conducted using real-world data from a local farm in Morris, Minnesota, and the results indicate the trade-off between cost and nitrogen loss. Importantly, we show that practicing effective nitrogen management can significantly reduce the nitrogen loss with only a small increase in net present cost.

Harnessing the Wind Power of the Ocean with Green Offshore Ammonia

“…In this techno-economic analysis, we aim to determine optimal designs of green offshore ammonia systems in various scenarios and gain insights into the main contributing factors with respect to the costs of such systems. To this end, we apply a superstructure-based design optimization approach adopted from our previous work . It selects the best configuration comprising a set of given design options while simultaneously optimizing the operational schedule under the chosen design.…”

“…Considering this level of detail in modeling the plant operations is particularly important due to the strong intermittency in wind availability. Several existing studies have shown that failing to account for such dynamics can lead to unsound design decisions. , For the sake of conciseness, we keep the description of the model brief; for more details, we refer to the reader to our previous work from which the formulation is adopted …”

“…To this end, we apply a superstructure-based design optimization approach adopted from our previous work. 29 It selects the best configuration comprising a set of given design options while simultaneously optimizing the operational schedule under the chosen design. In the following, we describe the system of interest in more detail, state the design options considered in our optimization, and present the corresponding model formulation.…”

“…38,39 For the sake of conciseness, we keep the description of the model brief; for more details, we refer to the reader to our previous work from which the formulation is adopted. 29 The design optimization problem with scheduling constraints is formulated as the following MILP…”

Electrochemical ammonia production from nitrates in agricultural tile drainage: Technoeconomic and global warming analysis

“…[20][21][22][23] Therefore, this work primarily focuses on emerging electrochemical technologies that can be combined to convert nitrogenous-waste to value added products, such as ammonia and other fertilizers, thereby partially offsetting the GWP and financial cost associated with ammonia produced by the Haber-Bosch process. 24,25 Our study examines a hypothetical three-part NCC system based on the three technologies listed above that have been demonstrated individually on the lab-scale. A schematic of this hypothetical system is presented in Figure 2, where the Haber-Bosch system boundaries are shown independently as well as supplemented by an NCC system.…”