Research Update: The nitride route to ammonia fertilizers: decoupling food and fossil fuel

A new three-year project at Kansas State University, sponsored by the U.S. Department of Energy, Basic Energy Sciences (U.S. DOE Office of Science, Award No. DE-SC0016453, "Step Catalysis to Synthesize Fossil-Free Ammonia at Atmospheric Pressure"), with $598,866 pursues ammonia for fertilizers produced from renewable resources with a new simple and rugged process. The team of Principal Investigator Dr. Peter Pfromm (Chemical Engineering), and co-Principal Investigators Dr.'s Bin Liu (Chemical Engineering) and Viktor Chikan (Chemistry) and their graduate students are investigating forming metal nitrides from metal alloy nanoparticles to activate nitrogen from air, and then synthesizing ammonia in a second step, all at atmospheric pressure and moderate temperatures. The recent precipitous decline in the cost of renewable electricity allows the needed hydrogen to be made by electrolysis of water so that the entire process is essentially fossil fuel free, economically competitive with fossil fuel based ammonia, and proceeds under conditions that will allow down-scaling and operation on stranded or intermittent renewable electricity

Preview of a detailed techno-economic analysis of diesel from algae: economic feasibility under sustainability constraints requires sustained unrealistically high algae yields if public subsidies are absent.

A detailed economical analysis of producing algae-derived biodiesel via open-pond aquaculture has been performed and is in peer-review for publication. The results of the economical analysis confirm the critical limitation of economic feasibility by achievable and fundamentally plausible biomass yields

Rational design of metal nitride redox materials for solar-driven ammonia synthesis

Fixed nitrogen is an essential chemical building block for plant and animal protein, which makes ammonia (NH3) a central component of synthetic fertilizer for the global production of food and biofuels. A global project on artificial photosynthesis may foster the development of production technologies for renewable NH3 fertilizer, hydrogen carrier and combustion fuel. This article presents an alternative path for the production of NH3 from nitrogen, water, and solar energy. The process is based on a thermochemical redox cycle driven by concentrated solar process heat at 700-1200°C that yields NH3 via the oxidation of a metal nitride with water. The metal nitride is recycled via solar-driven reduction of the oxidized redox material with nitrogen at atmospheric pressure. We employ electronic structure theory for the rational high-throughput design of novel metal nitride redox materials and to show how transition-metal doping controls the formation and consumption of nitrogen vacancies in metal nitrides. We confirm experimentally that iron doping of manganese nitride increases the concentration of nitrogen vacancies compared to no doping. The experiments are rationalized through the average energy of the dopant d-states, a descriptor for the theory-based design of advanced metal nitride redox materials to produce sustainable solar thermochemical ammonia

Economic feasibility of algal biodiesel under alternative public policies

The motivation for this research was to determine the influence of public policies on economic feasibility of producing algal biodiesel in a system that produced all its energy needs internally. To achieve this, a steady-state mass balance/unit operation system was modeled first. Open raceway technology was assumed for the production of algal feedstock, and the residual biomass after oil extraction was assumed fermented to produce ethanol for the transesterification process. The project assumed the production of 50 million gallons of biodiesel per year and using about 14% of the diesel output to supplement internal energy requirements. It sold the remainder biodiesel and ethanol as pure biofuels to maximize the rents from the renewable fuel standards quota system. Assuming a peak daily yield of 500 kg algal biomass (dry basis)/ha, the results show that production of algal biodiesel under the foregoing constraints is only economically feasible with direct and indirect public policy intervention. For example, the renewable fuel standards' tracking RIN (Renewable fuel Identification Number) system provides a treasury-neutral value for biofuel producers as does the reinstatement of the renewable fuel tax credit. Additionally, the capital costs of an integrated system are such that some form of capital cost grant from the government would support the economic feasibility of the algal biodiesel production

Enantioselective Transesterification by Candida antarctica Lipase B Immobilized on Fumed Silica

Enzymatic catalysis to produce molecules such as perfumes, flavors, and fragrances has the advantage of allowing the products to be labeled “natural” for marketing in the U.S., in addition to the exquisite selectivity and stereoselectivity of enzymes that can be an advantage over chemical catalysis. Enzymatic catalysis in organic solvents is attractive if solubility issues of reactants or products, or thermodynamic issues (water as a product in esterification) complicate or prevent aqueous enzymatic catalysis. Immobilization of the enzyme on a solid support can address the generally poor solubility of enzymes in most solvents. We have recently reported on a novel immobilization method for Candida antarctica Lipase B on fumed silica to improve the enzymatic activity in hexane. This research is extended here to study the enantioselective transesterification of (RS)-1-phenylethanol with vinyl acetate. The maximum catalytic activity for this preparation exceeded the activity (on an equal enzyme amount basis) of the commercial Novozyme 435® significantly. The steady-state conversion for (R)-1-phenylethanol was about 75% as confirmed via forward and reverse reaction. The catalytic activity steeply increases with increasing nominal surface coverage of the support until a maximum is reached at a nominal surface coverage of 230%. We hypothesize that the physical state of the enzyme molecules at a low surface coverage is dominated in this case by detrimental strong enzyme-substrate interactions. Enzyme-enzyme interactions may stabilize the active form of the enzyme as surface coverage increases while diffusion limitations reduce the apparent catalytic performance again at multi-layer coverage. The temperature-, solvent-, and long-term stability for CALB/fumed silica preparations showed that these preparations can tolerate temperatures up to 70°C, continuous exposure to solvents, and long term storage

Beyond fossil fuel–driven nitrogen transformations

How much carbon does it take to make nitric acid? The counterintuitive answer nowadays is quite a lot. Nitric acid is manufactured by ammonia oxidation, and all the hydrogen to make ammonia via the Haber-Bosch process comes from methane. That's without even accounting for the fossil fuels burned to power the process. Chen et al. review research prospects for more sustainable routes to nitrogen commodity chemicals, considering developments in enzymatic, homogeneous, and heterogeneous catalysis, as well as electrochemical, photochemical, and plasma-based approaches

Towards sustainable agriculture: fossil-free ammonia

Citation: Pfromm, P. H. (2017). Towards sustainable agriculture: Fossil-free ammonia. Journal of Renewable and Sustainable Energy, 9(3), 034702. https://doi.org/10.1063/1.4985090About 40% of our food would not exist without synthetic ammonia (NH3) for fertilization. Yet, NH3 production is energy intensive. About 2% of the world's commercial energy is consumed as fossil fuels for NH3 synthesis based on the century-old Haber-Bosch (H.-B.) process. The state of the art and the opportunities for reducing the fossil energy footprint of industrial H.-B. NH3 synthesis are discussed. It is shown that even a hypothetical utterly revolutionary H.-B. catalyst could not significantly reduce the energy demand of H.-B. NH3 as this is governed by hydrogen production. Renewable energy-enabled, fossil-free NH3 synthesis is then evaluated based on the exceptional and continuing cost decline of renewable electricity. H.-B. syngas (H2, N2) is assumed to be produced by electrolysis and cryogenic air separation, and then supplied to an existing H.-B. synthesis loop. Fossil-free NH3 could be produced for energy costs of about $232 per tonne NH3 without claiming any economic benefits for the avoidance of about 1.5 tonnes of CO2 released per tonne NH3 compared to the most efficient H.-B. implementations. Research into alternatives to the H.-B. process might be best targeted at emerging markets with currently little NH3 synthesis capacity but significant future population growth such as Africa. Reduced capital intensity, good scale-down economics, tolerance for process upsets and contamination, and intermittent operability are some desirable characteristics of NH3 synthesis in less developed markets, and for stranded resources. Processes that are fundamentally different from H.-B. may come to the fore under these specific boundary conditions

Emerging CO2 capture systems

In 2005, the IPCC SRCCS recognized the large potential for developing and scaling up a wide range of emerging CO2 capture technologies that promised to deliver lower energy penalties and cost. These included new energy conversion technologies such as chemical looping and novel capture systems based on the use of solid sorbents or membrane-based separation systems. In the last 10 years, a substantial body of scientific and technical literature on these topics has been produced from a large number of R&D projects worldwide, trying to demonstrate these concepts at increasing pilot scales, test and model the performance of key components at bench scale, investigate and develop improved functional materials, optimize the full process schemes with a view to a wide range of industrial applications, and to carry out more rigorous cost studies etc. This paper presents a general and critical review of the state of the art of these emerging CO2 capture technologies paying special attention to specific process routes that have undergone a substantial increase in technical readiness level toward the large scales required by any CO2 capture system

The minimum water consumption of ethanol production via biomass fermentation

The water consumption of fermentation-based bio-ethanol production has recently begun to attract public attention. We calculate a minimum consumption of 2.85 gal water/gal of ethanol produced assuming zero liquid discharge and otherwise current industrial practice data. Including cooling tower blowdown and drift this value may increase to on the order of 4 gal water/gal of ethanol produced. Reduction of the thermal energy input to the process is vital to reduce this irretrievable water consumption