Paper

Ammonia Absorbents with High Stability and High Capacity for Fast Cycling

Ammonia absorption is an alternative separation to condensation in ammonia production. Metal chloride salts selectively incorporate ammonia into their crystal lattices with remarkably high capacity. Regeneration and stability of these salts are further improved by dispersing them onto a porous silica support. Here, we discuss the optimal preparation methods of supported metal halides, as well as optimal conditions for uptake and release of ammonia. The metal halide salt particle size, support particle size, support composition and preparation methods are optimized for material stability, speed of uptake and release, and maximum ammonia capacity. An automated system was used to rapidly screen…

Paper

Synthesis and Assessment of Process Systems for Production of Ammonia Using Nitric Oxide in Combustion Exhaust Gas

Recently, ammonia is regarded as an alternative fuel without carbon dioxide (CO2). Numerous studies have been performed using ammonia as a fuel. Iki and Kurata confirmed the working of a prototype for the ammonia gas turbine, where ammonia burned in an environmentally benign way to generate electricity, exhausting only water and nitrogen [1]. From the view of cycle of ammonia for the development of a society with low carbon, it is required to synthesize carbon-free ammonia (green ammonia) in small plants. This green ammonia can be synthesized using renewable energy, with hydrogen from electrolysis of water and nitrogen from pressure…

Paper

Effect of Preparation Condition on Ammonia Synthesis over Ru/CeO

Development of the hydrogen carrier system is of great interest to utilization of renewable energy. To store renewable energy, especially for the electricity from photovoltaic and wind turbine, fluctuation of the generated electricity is not appropriate for the stable supply of the electric power. Also, the hydrogen production by the water electrolysis with the fluctuating electricity results in the fluctuation of hydrogen production. When we store the hydrogen derived from renewable energy in the carrier compounds, it is necessary to consider the reduction or smoothing of fluctuation in the hydrogen flow rate as a feed of chemical process. Although the…

Paper

Comparative Technoeconomic Analysis of Conventional and Absorbent-Enhanced Ammonia Synthesis

Ammonia is the second-most produced synthetic chemical and the main precursor for nitrogen-based fertilizer. In 2015, 160 million tons were produced globally, and global demand is expected to grow 1.5% annually until 2050 [1]. However, traditional ammonia production uses natural gas or coal as its hydrogen source, and as a result, is also responsible for more than 1% of global GHG emissions and 5% of global natural gas consumption [2]. Clearly, a more sustainable ammonia production scheme is needed. One such alternative is obtain hydrogen from electrolysis powered by wind- or solar-derived electricity. It has been proposed to perform this…

Paper

Mechanistic Insights into Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride Nanoparticles

Renewable production of ammonia, a building block for most fertilizers, via the electrochemical nitrogen reduction reaction (ENRR) is desirable; however, a selective electrocatalyst is lacking. Here we show that vanadium nitride (VN) nanoparticles are active, selective, and stable ENRR catalysts. ENRR with 15N2 as the feed produces both 14NH3 and 15NH3, which indicates that the reaction follows a Mars–van Krevelen mechanism. Ex situ and operando characterizations indicate that VN0.7O0.45 is the active phase for ENRR and the conversion of VN0.7O0.45 to the VN phase leads to catalyst deactivation. Quantitative isotopic labeling results identify the amounts of two different types of…

Paper

Yittria-Stabilized Zirconia (YSZ) Supports for Low Temperature Ammonia Synthesis

NH3 is important as the raw material for fertilizer production and high hydrogen density (17.7 wt. %) energy carrier. Conventionally, NH3 is synthesized through the well-known Haber-Bosch process at 400-500°C and P~150 bar. Both critical reaction conditions and massive production (145 mt NH3 in 2014 globally) make it one of the most energy extensive process, consuming 1-2% of the world’s total energy expense. Here we introduce YSZ as a more active Ru catalyst support than traditionally used supports such as Al2O3. The addition of Cs promoter increased rates an order of magnitude higher by reducing the apparent activation energy from…

Paper

An Integrated Evaluation Method with Application to a New Ammonia Synthesis Process Design

While keeping the traditional centralized large-scale chemical production, the increasing market volatility and the rising use of renewable resources will require new production ways such as distributed, modularized, and small-scale production. The new emerging processes are expected to provide more flexibility, shorter time to market, and better use of distributed renewable raw materials (e.g. biomass) and energy (e.g. solar and wind). However, the traditional process evaluation methods such as TEA (Techno-Economic Analysis) tend to lower the value of the new processes since the small-scale would make higher capital cost and lower operation efficiency. Therefore, a new evaluation method is required…

Paper

Ammonia Yields during Plasma-Assisted Catalysis Boosted By Hydrogen Sink Effect

Plasma-catalytic ammonia synthesis is known since early 1900s but the possible reaction pathways are currently under investigation. In this article, we present the use of various transition metals and gallium-rich alloys for plasma-catalytic ammonia synthesis. The best three metallic catalysts were identified to be Ni, Sn and Au with the highest ammonia yield of 34%. Furthermore, as compared to its constituent metals some alloys presented about 25-50% better yields. The metals employed were classified in two different categories according to their behavior during ammonia plasma-catalysis. Category I metals are nitrophobic and the measured concentration of Hα in the gas phase…

Paper

Ammonia – Could it replace HFO/LSFO?

The core of this presentation deals with the nature of ammonia, its natural characteristics that make it a future fuel solution candidate, the safety measures that need to be applied in order to carry it on board without endangering lives, environment & property, as well as whether this would be a feasible and cost- or risk-effective solution. For a long time, a lot of discussions have been centered around this subject, now bringing it to the immediate forefront & creating various questions that we will aim to answer to the interested individuals’, ship-managers’, businesses’, ship-owners’ and corporations’ satisfaction. Lloyd’s Register –…

Paper

Fuel Transition Scenarios for the Maritime Industry up to 2050

This paper will present some of the University College London Energy Institute’s recent and ongoing work on likely fuel transition scenarios for the maritime industry, and discuss potential scenarios under which ammonia could become a substantial fuel for shipping (i.e. carbon price, developments vs hydrogen, costs, and non-market factors).