Atomic Layer Deposition Coated Filters in Catalytic Filtration of Gasification Gas

Steel filter discs were catalytically activated by ALD, using a coating of supporting Al2O3 layer and an active NiO layer for gas cleaning. Prepared discs were tested for model biomass gasification and gas catalytic filtration to reduce or eliminate the need for a separate reforming unit for gasification gas tars and lighter hydrocarbons. Two different coating methods were tested. The method utilizing the stop-flow setting was shown to be the most suitable for the preparation of active and durable catalytic filters, which significantly decreases the amount of tar compounds in gasification gas. A pressure of 5 bar and temperatures of over 850 °C are required for efficient tar reforming. In optimal conditions, applying catalytic coating to the filter resulted in a seven-fold naphthalene conversion increase from 7% to 49%.

Electrical conductivity of wood sawdust using graphite catalytic coating: Unlocking the microwave-assisted pyrolysis efficiency of lignocellulosic biomass

The coating of the beech sawdust using a catalytic amount of graphite (as low as 0.25 wt.%) allowed a step improvement in the microwave-assisted thermolysis. Results demonstrated that the pyrolysis...

Exploration of Ni-P-Based Catalytic Electrodes for Hydrogen Evolution Reaction

High efficacy and industrial applicability on electrocatalytic hydrogen production is achieved by proper furnishing of components in the reaction cell. The idea on the basic mechanism of hydrogen evolution reaction (HER), efficient modification of available systems, and recent trends in the development strategies of suitable materials are very important to be explored to design novel systems for large-scale production. This review chapter discusses the scientific details on electrocatalytic HER and plausible materials used for catalyzing the reaction. And it outlines the trends in design and development of transition metal-based catalytic coating systems with a special focus on Ni-P alloy coating and scientific aspects of the methods and the materials used for the HER. On the whole, the discussion on HER and its catalytic systems provides an insight of their potential to be explored for enhanced energy production in hydrogen fuel cell technology for stationary and industrial applications.

Evaluating the behavior of catalyst coated nut-coke in blast furnace conditions

For efficient blast furnace ironmaking, it is desired to have low reducing agent rate, primarily coke rate. Developing technology to improve reaction efficiency of the blast furnace is extremely important as it has the potential to allow a decrease in the reducing agent rate as well as CO2 emissions. The reaction efficiency of blast furnace can be improved by lowering the Thermal Reserve Zone (TRZ) temperature; which is also the starting temperature of coke gasification reaction. In present study, nut-coke has been coated with in-plant waste, consisting mainly of iron oxide and calcium oxide, as catalyst. There was a clear increase of 10 points in the reactivity of coated nut-coke. The coated nut-coke have been subjected to non-standard high temperature experiments simulating blast furnace conditions with reducing gas consisting of CO, CO2 and N2 to capture the effect of catalytic coating on the onset of gasification reaction. The high temperature experiments carried out advise the following: i) A drop of 100 °C in the reaction beginning temperature of catalyst coated nut-coke as compared to non-coated one ii) A typical calculation shows that the lowering of reaction beginning temperature corresponds to a potential carbon rate savings of about 2.5 kg/ton of hot metal (thm). Furthermore, in a trial conducted at blast furnace with charging catalyst coated nut-coke, it has been observed that the carbon rate during the trial period was 3 kg/thm lower than the base period. The findings of blast furnace trial agree with that of the experimental one.

Simulation of Light Propagation in Photochemical Fixed-Bed Reactors Using a BRDF-Based Model

<div> <p>Modelling light transport in fixed-bed photochemical reactors can be challenging if the geometry of the packing is the object of investigation. In this manuscript, we present a physically-based model of light transport for the simulation of fixed-bed photochemical reactors to be coupled with explicit consideration of reactor geometry: spatial properties of the fixed bed, such as size, shape, distribution and quality of the surface of packing particles are used as input variables. The existence of a catalytic coating on the packing surface, and its major properties such as spectral coefficient of absorption and surface rugosity can also be easily coupled with the light propagation algorithm. The model was built upon the framework of the bidirectional reflectance distribution function (BRDF), using the microfacets theory (MFT) to evaluate an approximate solution. As an example of application, easily measurable experimental data, such as UV absorption/extinction spectra and surface roughness, and readily available literature data on spectral refractive indices are used as inputs to calculate (i) the fate of the irradiated energy (percentage absorbed, transmitted and scattered-out) and (ii) the spatial distribution of the scattered rays. Taken together, these output data should offer the engineer guidelines for the design of fixed-bed photochemical reactors with optimised light collection and distribution.</p> </div> <br>

Simulation of Light Propagation in Photochemical Fixed-Bed Reactors Using a BRDF-Based Model

<div> <p>Modelling light transport in fixed-bed photochemical reactors can be challenging if the geometry of the packing is the object of investigation. In this manuscript, we present a physically-based model of light transport for the simulation of fixed-bed photochemical reactors to be coupled with explicit consideration of reactor geometry: spatial properties of the fixed bed, such as size, shape, distribution and quality of the surface of packing particles are used as input variables. The existence of a catalytic coating on the packing surface, and its major properties such as spectral coefficient of absorption and surface rugosity can also be easily coupled with the light propagation algorithm. The model was built upon the framework of the bidirectional reflectance distribution function (BRDF), using the microfacets theory (MFT) to evaluate an approximate solution. As an example of application, easily measurable experimental data, such as UV absorption/extinction spectra and surface roughness, and readily available literature data on spectral refractive indices are used as inputs to calculate (i) the fate of the irradiated energy (percentage absorbed, transmitted and scattered-out) and (ii) the spatial distribution of the scattered rays. Taken together, these output data should offer the engineer guidelines for the design of fixed-bed photochemical reactors with optimised light collection and distribution.</p> </div> <br>

Collaboration and competition between active sheets for self-propelled particles

Biological species routinely collaborate for their mutual benefit or compete for available resources, thereby displaying dynamic behavior that is challenging to replicate in synthetic systems. Here we use computational modeling to design microscopic, chemically active sheets and self-propelled particles encompassing the appropriate synergistic interactions to exhibit bioinspired feeding, fleeing, and fighting. This design couples two different mechanisms for chemically generating motion in fluid-filled microchambers: solutal buoyancy and diffusiophoresis. Catalyst-coated sheets, which resemble crabs with four distinct claws, convert reactants in solution into products and thereby create local variations in the density and chemical composition of the fluid. Via the solutal buoyancy mechanism, the density variations generate fluid flows, which modify the shape and motility of the crabs. Concomitantly, the chemical variations propel the motion of the particles via diffusiophoresis, and thus, the crabs’ and particles’ motion becomes highly interconnected. For crabs with restricted lateral mobility, these two mechanisms can be modulated to either drive a crab to catch and appear to feed on all of the particles or enable the particles to flee from this sheet. Moreover, by adjusting the sheet’s size and the catalytic coating, two crabs can compete and fight over the motile, diffusiophoretic particles. Alternatively, the crabs can temporally share resources by shuttling the particles back and forth between themselves. With completely mobile sheets, four crabs can collaborate to perform a function that one alone cannot accomplish. These findings provide design rules for creating chemically driven soft robotic sheets that significantly expand the functionality of microfluidic devices.