Numerical Modeling of Solar Thermo-Chemical Water-Splitting Reactor

Author(s):  
Darryl L. James ◽  
Nathan P. Siegel ◽  
Richard B. Diver ◽  
Barry D. Boughton ◽  
Roy E. Hogan

Production of hydrogen using solar thermal energy has the potential to be a viable alternative to other hydrogen production methods, typically fossil-fuel driven processes. Thermochemical reactions for splitting water require high temperatures to operate effectively, for which solar is well-suited. Numerical modeling to investigate the concept of a solar-driven reactor for splitting water is presented in detail in this paper for an innovative reactor, known as the “counter-rotating-ring receiver/reactor/recuperator” (CR5) solar thermochemical heat engine that is presently under development. In this paper, details of numerical simulations predicting the thermal/fluid behavior of the innovative solar-driven thermo-chemical reactor are described in detail. These scoping calculations have been used to provide insight into the thermal behavior of the counter-rotating reactor rings and to assess the degree of flow control required for the CR5 concept.

Author(s):  
Dulani P. A. Kodippili ◽  
Robin A. L. Drew ◽  
Michelle R. Nokken

Nanosilica (NS) has shown significant beneficial effects on concrete. However, the utilization of NS to achieve its maximum benefits is limited by the agglomeration of nanoparticles, which is associated with production methods and the method of NS dispersion in concrete. In this study, the effects of the utilization of NS as a suspension in calcium hydroxide (CH) on the hydration characteristics and the microstructure of the cement pastes were investigated with different levels of cement replacements (1%, 2%, 4%, and 6% NS) at 2, 7, and 28 days. The hydration of the cement pastes was investigated by isothermal calorimetry, and the measurement of CH content by thermogravimetry. The microstructures were analyzed by scanning electron microscopy and by energy dispersive X-ray spectroscopic mapping. The microstructure of the pastes was characterized by analyzing the pore size and the pore size distribution using mercury intrusion porosimetry (MIP). The calorimetric studies indicated that the replacing cement by NS derived by this method leads to faster hydration up to 4% replacement. The CH contents could be reduced by the incorporation of NS. The pore structures revealed that the pastes with NS had become comparably denser than the pastes without NS. A positive insight into the durability characteristics was shown by the results of the MIP when using NS as suspensions.


Author(s):  
Daniel Peterson ◽  
Sourabh V. Apte ◽  
Vinod Narayanan ◽  
John Schmitt

Numerical modeling of methane-steam reforming is performed in a mini/microchannel with heat input through Nickel-deposited channel walls. The low-Mach number, variable density Navier-Stokes equations together with multicomponent reactions are solved using a parallel numerical framework. Methane-steam reforming is modeled by three reduced-order reactions occurring on the reactor walls. The surface reactions in the presence of Nickel catalyst are modeled as Neumann boundary conditions to the governing equations. Effects of the total heat input, heat flux profile, and inlet methane-steam molar concentration on production of hydrogen are investigated in detail.


2017 ◽  
Vol 26 (11) ◽  
pp. 1750138 ◽  
Author(s):  
Kh. Jafarzade ◽  
J. Sadeghi

In this paper, we take cosmological constant as a thermodynamical pressure and its conjugate quantity as a thermodynamical volume. This expression helps us to investigate the phase transition and holographic heat engine. So, in order to have Van der Waals fluid behavior in Horava–Lifshitz (HL) black hole, we modified the solution of such black hole with some cosmology ansatz. Also from holographic heat engine, we obtain Carnot efficiency for the HL black hole. The phase transition of the system lead us to investigate the stability condition for the corresponding black hole. In that case, we show that the stability exist only in special region of black hole.


1998 ◽  
Vol 40 (2) ◽  
pp. 167-183 ◽  
Author(s):  
Takashi YAMAISHI ◽  
Hitoshi KOBAYASHI ◽  
Tokichiro TANI ◽  
Akio OKAMOTO ◽  
Hiroyuki TOSAKA ◽  
...  

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 833-853 ◽  
Author(s):  
K. R. Kelly

Love wave propagation is studied by investigating numerical modeling results for several examples of geologic interest. The modal characteristics of the results are clarified by the use of narrow band‐pass filters and two‐dimensional Fourier transforms in range and time. Such processing makes it possible to study changes in phase and group velocity for the various modes and to locate points of reflection. This permits one to gain insight into changes in the physical properties of the surface channel supporting the waves.


Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1425
Author(s):  
Mohammed El Khalloufi ◽  
Olivier Drevelle ◽  
Gervais Soucy

For several decades, the metallurgical industry and the research community worldwide have been challenged to develop energy-efficient and low-cost titanium production processes. The expensive and energy-consuming Kroll process produces titanium metal commercially, which is highly matured and optimized. Titanium’s strong affinity for oxygen implies that conventional Ti metal production processes are energy-intensive. Over the past several decades, research and development have been focusing on new processes to replace the Kroll process. Two fundamental groups are categorized for these methods: thermochemical and electrochemical. This literature review gives an insight into the titanium industry, including the titanium resources and processes of production. It focuses on ilmenite as a major source of titanium and some effective methods for producing titanium through extractive metallurgy processes and presents a critical view of the opportunities and challenges.


OENO One ◽  
2020 ◽  
Vol 54 (4) ◽  
pp. 733-743
Author(s):  
Edouard Pelonnier-Magimel ◽  
Pinelopi Mangiorou ◽  
Darriet Philippe ◽  
Gilles De Revel ◽  
Michael Jourdes ◽  
...  

Aim: The evolution of consumer expectations has led to the development of new production methods using low inputs. From an oenological point of view, these methods include the production of wines without any SO2 being added throughout the process. These wines are becoming very popular among consumers, but the absence of SO2 during winemaking increases the risk of stability problems. Such wines have been poorly explored in the literature and there is thus a real need for them to be characterised. This study was developed to evaluate whether Bordeaux quality wines produced without added SO2 have their own typicality, and it provides an insight into current wine production.Methods and results: From a batch of fifty-two commercial Bordeaux red wines produced without adding SO2 and twenty red wines made according to the usual winemaking methods, a selection tasting was performed to eliminate wines with at least one defect further to a sensory space evaluation. In a second phase, the Napping test was applied to defect-free wines to evaluate the sensory specificities of wines produced without SO2 addition. The wines without SO2 addition presented a much higher frequency of defects than those with SO2 (70 % vs 15 % respectively). Defects described in wines without added SO2 were: “Oxidation” (47 %), “Volatile phenols” (31 %), “Mousy off-flavor” (10 %), “Reduction” (8 %) and “Vegetable” (4 %). Since the study focused on quality wines with or without SO2 addition, it was difficult for the tasters to discriminate between them according to their overall technical pathway.Conclusion: This approach has revealed that despite the large number of “non-added SO2” wines with defects, upon blind tasting, expert tasters highlighted some “non-added SO2” wines without defects. Nevertheless, at equivalent quality levels within the same geographic region, and in non-targeted sensory tests, wines with and without SO2 addition were considered to be quite similar.Significance of the study: This study was a first sensory step toward the objective characterisation of “non-added SO2” wines, enabling further work to highlight markers of quality in wines without SO2 addition and to develop the production of “non-added SO2” wines without defects. Nevertheless, at this stage, our results show that the absence of sulfites during the whole winemaking process, including bottling, increases the risk of the development of defects.


2014 ◽  
Vol 51 (3) ◽  
pp. 260-271 ◽  
Author(s):  
Hamid Batenipour ◽  
Marolo Alfaro ◽  
David Kurz ◽  
Jim Graham

The paper examines the behaviour of a highway embankment in an area of discontinuous permafrost about 18 km northwest of Thompson, Manitoba. Frequent maintenance has been required. Research involved site investigation, laboratory testing, installing instruments, data collection, and numerical modeling. The paper reports data from almost 3 years of observation. Measurements of ground temperatures suggest that formerly ice-rich foundation soil has thawed under the toe and side-slope. Approximate values of segregation potential have been back-calculated from observations of settlements and temperatures. Results provide insight into the nature and cause of deformations of the embankment.


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