Objective Ammonia is an effective zero-carbon fuel, and green ammonia co-firing has emerged as one of the key technical pathways for the low-carbon transformation of thermal power plants in China. This approach not only addresses the carbon reduction challenges of thermal power plants but also facilitates the large-scale consumption and long-term storage of renewable energy sources like wind and solar power. Consequently, the large-scale, efficient, economical, and safe storage and transportation of liquid ammonia is of paramount importance.
Methods The advantages and disadvantages of ammonia fuel were analyzed from its properties and energy storage capabilities, and the transportation and storage methods of liquid ammonia were introduced in detail. To improve the existing liquid ammonia storage process, a novel method combining medium-pressure storage at ambient temperature with low-pressure storage at lowered temperature was proposed, effectively leveraging the strengths of both methods. This method offers advantages such as energy and water savings, high safety, and reasonable investment costs. Taking the 10％ (by calorific value) green ammonia co-firing project of 2×660 MW units in a coal-fired thermal power plant as a case study, specific technical solutions for liquid ammonia storage and transportation were provided, along with the selection of main equipment design parameters and a comprehensive economic comparison of three liquid ammonia storage methods.
Results In the scenario of green ammonia co-firing in thermal power plants, pipeline transportation offers significant advantages, including improved economic efficiency, high transportation efficiency, and enhanced safety, making it the most viable large-scale method for liquid ammonia transportation. Based on economic analysis and safety considerations, the proposed method of combining medium-pressure storage at ambient temperature with low-pressure storage at lowered temperature should utilize a minimal number of spherical tanks for medium-pressure storage, ideally 2 to 3. The study identified a critical storage duration of 5 days for liquid ammonia. If storage exceeds this duration, the combined storage method is recommended to better balance economy and safety. Conversely, if storage is within the duration, the economic efficiency of the three storage methods is comparable, and the safer option of medium-pressure storage at ambient temperature is recommended.
Conclusion Currently, it is imperative to establish Chinese national standards for liquid ammonia pipeline transportation and expedite the development of green ammonia co-firing demonstration projects in thermal power plants to achieve the goals of “carbon peaking and carbon neutrality”.
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