There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

Despite being first demonstrated over 160 years ago, and offering significant environmental benefits and high electrical efficiency, it is only in the last two decades that fuel cells have offered a realistic prospect of being commercially viable. The solid oxide fuel cell (SOFC) offers great promise and is presently the subject of intense research activity. Unlike other fuel cells the SOFC is a solid-state device which operates at elevated temperatures. This review discusses the particular issues facing the development of a high temperature solid-state fuel cell and the inorganic materials currently used and under investigation for such cells, together with the problems associated with operating SOFCs on practical hydrocarbon fuels.

/pdf/solid-oxide-fuel-cells-2vfiwiriu1.pdf

Solid oxide fuel cells

A study is conducted to demonstrate catalytic dehydrogenation of light alkanes on metals and metal oxides. The study provides a complete overview of the materials used to catalyze this reaction, as dehydrogenation for the production of light olefins has become extremely relevant. Relevant factors, such as the specific nature of the active sites, as well as the effect of support, promoters, and reaction feed on catalyst performance and lifetime, are discussed for each catalytic Material. The study compares different catalysts in terms of the reaction mechanism and deactivation pathways and catalytic performance. The duration of the dehydrogenation step depends on the heat content of the catalyst bed, which decreases rapidly due to the endothermic nature of the reaction. Part of the heat required for the reaction is introduced to the reactors by preheating the reaction feed, additional heat being provided by adjacent reactors that are regenerating the coked catalysts.

Catalytic dehydrogenation of light alkanes on metals and metal oxides.

The steam reforming of glycerol (1,2,3-propantriol) was investigated with non-substituted and partially Ce substituted La 1− x Ce x NiO 3 mixed oxides where x  = 0, 0.1, 0.3 or 0.7, and the activities were compared with Pt metal catalysts. The catalysts were characterised by temperature-programmed reduction (TPR), X-ray powder diffraction (XRD), BET surface area and carbon content. The Ni was easily reduced in the La 0.3 Ce 0.7 NiO 3 structure. The experimental results were compared with the thermodynamic equilibrium concentrations, which were calculated for the system with non-stochiometric method. The La 0.3 Ce 0.7 NiO 3 catalyst was highly active in the glycerol steam reforming with conversions approaching to the equilibrium at temperatures between 500 and 700 °C. The formation of carbonaceous deposits on the La 0.3 Ce 0.7 NiO 3 was smallest among all the investigated La 1− x Ce x NiO 3 catalysts. Unchanged catalyst surface area (BET) during operation and low carbon deposition after reaction confirm the efficient operation and high stability of the non-noble, inexpensive catalyst of La 0.3 Ce 0.7 NiO 3 .

Steam reforming of glycerol : The experimental activity of La1 -XCeXNiO3 catalyst in comparison to the thermodynamic reaction equilibrium

The alloying of Pt with Ga delivered from a hydrotalcite-like support was investigated as a strategy to produce bimetallic catalysts for propane dehydrogenation. A series of Pt/Mg(Al,Ga)Ox catalysts (2–3 wt % Pt, Ga/Pt molar ratios between 0 and 10) and a model Pt/Ga2O3 catalyst (4 wt % Pt, Ga/Pt molar ratio of 50) were characterized by means of X-ray diffraction (XRD), transmission electron microscopy, and activity measurements (873 K, Wcat/FC3H8,0 = 25 kgcat·s·mol–1 and PC3H8,0 = 5 kPa at a total pressure of 101.3 kPa). XRD patterns taken during temperature-programmed reduction in 5% H2/He and isothermal reduction/oxidation cycling between 5% H2/He and 20% O2/N2 at 873 K revealed dynamic alloy formation and segregation that depended upon the gas environment and Ga content. Alloying on the Pt/Mg(Al,Ga)Ox catalyst with a Ga/Pt ratio of 2 could not be observed by XRD. For a Ga/Pt ratio of 10, an alloy with a diffraction peak at 40.2° was formed during the initial reduction. After subsequent reduction/oxida...

Delivering a Modifying Element to Metal Nanoparticles via Support: Pt–Ga Alloying during the Reduction of Pt/Mg(Al,Ga)Ox Catalysts and Its Effects on Propane Dehydrogenation

Hydrogen can be produced in electrically heated reactors, reducing CO2 emissions Vast amounts of energy are needed to synthesize the hundreds of millions of tons of chemicals used in everyday life each year. To meet that demand, the chemical industry uses the energy released during fuel combustion, thereby producing a seventh of the anthropogenic emissions of greenhouse gases. Climate change makes it mandatory to replace fossil fuels in chemical production processes and reduce their climate impact (1–3). On page 756 of this issue, Wismann et al. (4) focus on reducing the CO2 emissions created during the production of molecular hydrogen (H2), a key building block for ammonia-derived fertilizers, through steam reforming of methane. This industrial process releases 9 kg of CO2 per kg of H2, a quarter of which comes from fuel combustion.

https://science.sciencemag.org/content/sci/364/6442/734.full.pdf

Making chemicals with electricity

Anaerobic digestion can already at small scale effectively convert (waste) biomass to biogas. This biogas is typically combusted to generate electricity and heat, which is incentivized by regulatory support schemes. Because biogas can also be upgraded to biomethane and subsequently injected into the gas grid, the anaerobic digester can be considered as a means to connect decentralized biomass production to a centralized gas grid. We currently estimate the level of required government support to realize a profitable investment in Europe at 20–50 € MWhe−1 for the valorization of an average biogas in a combined heat and power unit, and at 15–25 € MWh−1 for the production of pipeline-quality biomethane, typically used as fuel. Here we explore, both technically and economically, an alternative scenario where biogas is upgraded to biomethane, injected into the existing gas grid, and used elsewhere to produce CO, syngas or H2. The super-dry reforming of CH4, a chemical looping approach using up to three CO2 molecules per CH4, allows an intensified production of CO as a feedstock for synthesis of platform chemicals and fuels through CO2 utilization. Even without subsidies, at present values and costs, this creates an economically positive case which can promote anaerobic digestion as an important driver for a new bio-industry. This approach avoids biomass transportation, in contrast with present biorefineries, while effectively valorizing decentralized biomass feedstocks such as agricultural waste or energy crops.

Vladimir Galvita

Papers

Steam reforming of glycerol : The experimental activity of La1 -XCeXNiO3 catalyst in comparison to the thermodynamic reaction equilibrium

Delivering a Modifying Element to Metal Nanoparticles via Support: Pt–Ga Alloying during the Reduction of Pt/Mg(Al,Ga)Ox Catalysts and Its Effects on Propane Dehydrogenation

Making chemicals with electricity

Upgrading the value of anaerobic digestion via chemical production from grid injected biomethane

Reaction network for the total oxidation of toluene over CuO-CeO2/Al2O3