Chemical-looping combustion (CLC) for inherent CO2 separations—a review

Horizon 2020 Project “Design for Resource and Energy efficiency in CerAMic Kilns- DREAM Project (Grant No: 723641), Horizon 2020 Industrial THERMal energy recovery conversion and management (Grant No:680599) and ESPRC (Grant No: EP/P004636/1)

https://bura.brunel.ac.uk/bitstream/2438/16137/3/Fulltext.pdf

Waste Heat Recovery Technologies and Applications

Thermal energy storage (TES) for industrial waste heat (IWH) recovery: A review

The published literature relating to damage to SOFCs caused by redox cycling of Ni-based anodes is reviewed. The review covers the kinetics of Ni oxidation and NiO reduction (as single phases and as constituents of composites with yttria-stabilised zirconia, YSZ), the dimensional changes associated with redox cycling and the effect of this on the mechanical integrity and electrical performance of cells and stacks. A critical parameter is the expansion strain that is caused by oxidation. Several studies report that the first complete oxidation of a Ni/YSZ composite causes a linear expansion of the order of 1%, but the actual values vary substantially between different investigations. The oxidation strain is the result of microstructural irreversibility during the redox process and leads to strain accumulation over several redox cycles. This can cause mechanical disruption to an anode, anode support or other cell components attached to the anode.

A simplified mechanical model of the stress and damage that are likely to be caused by anode expansion is proposed and applied to anode-supported, electrolyte-supported and inert substrate-supported cell configurations. This allows the maximum oxidation strain to avoid damage in each configuration to be estimated.

Redox Cycling of Ni-Based Solid Oxide Fuel Cell Anodes: A Review

A review of waste heat recovery technologies towards molten slag in steel industry

Energy recovery from high temperature slags

Reduction kinetics of Goro nickel oxide using hydrogen

Gaseous and solid fluxes play an important role in the degassing, demagging, and fluxing of aluminum and its alloys. Inert as well as reactive gases, or hexachloroethane, may be used to remove dissolved hydrogen and sodium. Magnesium may be removed by chlorine or an aluminum-fluoride-containing flux. Fluxes based on a KCl-NaCl mixture may be used to cover and protect the metal from oxidation. To recover aluminum from drosses, a more reactive flux containing cryolite or some other fluoride may be used. In this article, the thermodynamics of aluminum melting and refining are analyzed in terms of the behavior of sodium, magnesium, and calcium. The coalescence of aluminum drops in salt fluxes improves with fluoride additions. With increasing MgCl2 contents in the flux, the effects of NaF and KF additions become much less pronounced.

The properties and uses of fluxes in molten aluminum processing

One major problem in the photovoltaic industry is the high price of refined solar grade silicon. In this research, a new method for refining metallurgical grade silicon to solar grade silicon is investigated. The main steps include alloying with copper, solidification, grinding and gravity separation. A metallography study showed the presence of only two microconstituents, mainly pure silicon dendrites and Cu3Si intermetallic. Chemical analysis revealed a several times higher impurity level in the Cu3Si intermetallic than in the pure silicon; furthermore, the amount of nine elements in the refined silicon is reduced below the ICP detection limit. The acquired results showed that the suggested method is efficient in removing impurities from the metallurgical grade silicon with great potential for further development.

Refining Silicon for Solar Cell Application by Copper Alloying

A combination of solvent refining and flux treatment was employed to remove boron and phosphorus from crude silicon to acceptable levels for solar applications Metallurgical grade silicon (MG-Si) was alloyed with pure copper, and the alloy was subjected to refining by liquid CaO-SiO2-Na2O-Al2O3 slags at 1773 K (1500 °C) The distribution of B and P between the slags and the alloy was examined under a range of slag compositions, varying in CaO:SiO2 and SiO2:Al2O3 ratios and the amount of Na2O The results showed that both basicity and oxygen potential have a strong influence on the distributions of B and P With silica affecting both parameters in these slags, a critical $$ P_{{{\text{O}}_{2} }} $$
 could be identified that yields the highest impurity pick-up The addition of Na2O to the slag system was found to increase the distributions of boron and phosphorus A thermodynamic evaluation of the system showed that alloying copper with MG-Si leads to substantial increase of boron distribution coefficient The highest boron and phosphorus distribution coefficients are 47 and 11, respectively Using these optimum slags to reduce boron and phosphorus in MG-Si to solar grade level, a slag mass about 03 times and 17 times mass of alloy would be required, respectively

/pdf/removal-of-boron-and-phosphorus-from-silicon-using-cao-sio2-1n03stjrwd.pdf

Torstein A. Utigard

Papers

Energy recovery from high temperature slags

Reduction kinetics of Goro nickel oxide using hydrogen

The properties and uses of fluxes in molten aluminum processing

Refining Silicon for Solar Cell Application by Copper Alloying

Removal of Boron and Phosphorus from Silicon Using CaO-SiO2-Na2O-Al2O3 Flux