Novel Catalysts and Processing Technologies for Production of Aerospace Fuels from Non-Petroleum Raw Materials

Transportation fuels production (including aerospace propellants) from non-traditional sources (gases, waste materials, and biomass) has been an active area of research and development for decades. Reducing terrestrial waste streams simultaneous with energy conversion, plentiful biomass, new low-cost methane sources, and/or extra-terrestrial resource harvesting and utilization present significant technological and business opportunities being realized by a new generation of visionary entrepreneurs. We examine several new approaches to catalyst fabrication and new processing technologies to enable utilization of these nontraditional raw materials. Two basic processing architectures are considered: a single-stage pyrolysis approach that seeks to basically re-cycle hydrocarbons with minimal net chemistry or a two-step paradigm that involves production of supply or synthesis gas (mainly carbon oxides and H2) followed by production of fuel(s) via Sabatier or methanation reactions and/or Fischer-Trpsch synthesis. Optimizing the fraction of product stream relevant to targeted aerospace (and other transportation) fuels via modeling, catalyst fabrication and novel reactor design are described. Energy utilization is a concern for production of fuels for either terrestrial or space operations; renewable sources based on solar energy and/or energy efficient processes may be mission enabling. Another important issue is minimizing impurities in the product stream(s), especially those potentially posing risks to personnel or operations through (catalyst) poisoning or (equipment) damage. Technologies being developed to remove (and/or recycle) heteroatom impurities are briefly discussed as well as the development of chemically robust catalysts whose activities are not diminished during operation. The potential impacts on future missions by such new approaches as well as balance of system issues are addressed

DFT/QTAIM Analysis of the Effect of Late Transition Metal Doping on Methane Selectivity in Fischer–Tröpsch Catalysis

The effect of late transition metal substitution into Fe(1 0 0), Ni(1 1 1), and Co(0 0 0 1) surface analogs has been investigated density functional theory (DFT) methods. The surface was modeled using a 7-atom cluster, with perimeter atoms saturated with hydrogen atoms to approximate surface coordination and mitigate dangling bond artifacts. All calculations were performed at the B3PW91 level of theory with the LANL2DZ basis. Eight surface adsorbates were studied: C, CH, CH2, and CH3 represented the hydrogenating steps on surface carbide, while C+CH, CH+CH, C+CH3, and CH2+CH2 represented four competitive coupling pathways. A review of the effect of Cu, Ag, Au, and Pd on the reaction energies and barriers associated with these critical steps is discussed. QTAIM is employed to develop a picture of the electronic environment associated with methane selectivity. Attention is focused on the charge trends for the involved surface atoms and coupling species. Our results suggest that promising candidates for the reduction of FT methane selectivity include Au and Pd on Ni, Au and Ag on Co, and Cu, Ag, and Pd on Fe

Effect of Ag and Pd Promotion on CH4 Selectivity in Fe(100) Fischer-Tropsch Catalysis

The current CO2 utilization market is dominated by enhanced oil recovery and urea manufacturing; yet, the scale of demand falls well short of that deemed necessary to make a significant impact on climate change. CO2 conversion to fuels, however, is a utilization technology that can theoretically match the scale of projected CO2 capture. Fischer-Tropsch (FT) processing is a long-established technology for converting non-petroleum based precursors into transportation fuels and other valuable chemicals. Here, we report the effects of Pd and Ag doping on CH4 selectivity over Fe(100), a common FT catalyst, as these metals have shown potential in the direct conversion of co-fed CO2. Adsorption energies for pathway specific C1 and C2 species were weakened in the presence of Ag and Pd by ca. 0.55 eV and 0.35 eV, respectively. Further, while both Ag-and Pd-promoted surfaces show decreased CH4 production, Ag introduces a prohibitively high coupling barrier; thus, only Pd offered a decrease in CH4 selectivity (-36%) relative to unmodified Fe(100)

Effect of Ag and Pd Promotion on CH4 Selectivity in Fe(100) Fischer-Tropsch Catalysis

The current CO2 utilization market is dominated by enhanced oil recovery and urea manufacturing; yet, the scale of demand falls well short of that deemed necessary to make a significant impact on climate change. CO2 conversion to fuels, however, is a utilization technology that can theoretically match the scale of projected CO2 capture. Fischer-Tropsch (FT) processing is a long-established technology for converting non-petroleum based precursors into transportation fuels and other valuable chemicals. Here, we report the effects of Pd and Ag doping on CH4 selectivity over Fe(100), a common FT catalyst, as these metals have shown potential in the direct conversion of co-fed CO2. Adsorption energies for pathway specific C1 and C2 species were weakened in the presence of Ag and Pd by ca. 0.55 eV and 0.35 eV, respectively. Further, while both Ag-and Pd-promoted surfaces show decreased CH4 production, Ag introduces a prohibitively high coupling barrier; thus, only Pd offered a decrease in CH4 selectivity (-36%) relative to unmodified Fe(100)

Carbon Capture and Utilization in the Industrial Sector

The fabrication and manufacturing processes of industrial commodities such as iron, glass, and cement are carbon-intensive, accounting for 23% of global CO₂ emissions. As a climate mitigation strategy, CO₂ capture from flue gases of industrial processesmuch like that of the power sectorhas not experienced wide adoption given its high associated costs. However, some industrial processes with relatively high CO₂ flue concentration may be viable candidates to cost-competitively supply CO₂ for utilization purposes (e.g., polymer manufacturing, etc.). This work develops a methodology that determines the levelized cost ($/tCO₂) of separating, compressing, and transporting carbon dioxide. A top-down model determines the cost of separating and compressing CO₂ across 18 industrial processes. Further, the study calculates the cost of transporting CO₂ via pipeline and tanker truck to appropriately paired sinks using a bottom-up cost model and geo-referencing approach. The results show that truck transportation is generally the low-cost alternative given the relatively small volumes (ca. 100 kt CO₂/a). We apply our methodology to a regional case study in Pennsylvania, which shows steel and cement manufacturing paired to suitable sinks as having the lowest levelized cost of capture, compression, and transportation

Complement system modulation as a target for treatment of arrhythmogenic cardiomyopathy

Inflammation may contribute to disease progression in arrhythmogenic cardiomyopathy (ACM). However, its role in this process is unresolved. Our goal was to delineate the pathogenic role of the complement system in a new animal model of ACM and in human disease. Using cardiac histology, echocardiography, and electrocardiography, we have demonstrated that the desmin-null mouse (Des-/-) recapitulates most of the pathognomonic features of human ACM. Massive complement activation was observed in the Des-/- myocardium in areas of necrotic cells debris and inflammatory infiltrate. Analysis of C5aR-/-Des-/- double-null animals and a pharmaceutical approach using a C5a inhibitor were used to delineate the pathogenic role of the complement system in the disease progression. Our findings indicate that inhibiting C5aR (CD88) signaling improves cardiac function, histopathology, arrhythmias, and survival after endurance. Containment of the inflammatory reaction at the initiation of cardiac tissue injury (2-3 weeks of age), with consequently reduced myocardial remodeling and the absence of a direct long-lasting detrimental effect of C5a-C5aR signaling on cardiomyocytes, could explain the beneficial action of C5aR ablation in Des-/- cardiomyopathy. We extend the relevance of these findings to human pathophysiology by showing for the first time significant complement activation in the cardiac tissues of patients with ACM, thus suggesting that complement modulation could be a new therapeutic target for AC

Complement system modulation as a target for treatment of arrhythmogenic cardiomyopathy

Inflammation may contribute to disease progression in arrhythmogenic cardiomyopathy (ACM). However, its role in this process is unresolved. Our goal was to delineate the pathogenic role of the complement system in a new animal model of ACM and in human disease. Using cardiac histology, echocardiography, and electrocardiography, we have demonstrated that the desmin-null mouse (Des-/-) recapitulates most of the pathognomonic features of human ACM. Massive complement activation was observed in the Des-/- myocardium in areas of necrotic cells debris and inflammatory infiltrate. Analysis of C5aR-/-Des-/- double-null animals and a pharmaceutical approach using a C5a inhibitor were used to delineate the pathogenic role of the complement system in the disease progression. Our findings indicate that inhibiting C5aR (CD88) signaling improves cardiac function, histopathology, arrhythmias, and survival after endurance. Containment of the inflammatory reaction at the initiation of cardiac tissue injury (2-3 weeks of age), with consequently reduced myocardial remodeling and the absence of a direct long-lasting detrimental effect of C5a-C5aR signaling on cardiomyocytes, could explain the beneficial action of C5aR ablation in Des-/- cardiomyopathy. We extend the relevance of these findings to human pathophysiology by showing for the first time significant complement activation in the cardiac tissues of patients with ACM, thus suggesting that complement modulation could be a new therapeutic target for ACM

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London