Composite mesoporous SiO2-Al2O3 supported Fe, FeCo and FeRu catalysts for Fischer-Tropsch studies in a 3-D printed stainless-steel microreactor

Author(s):  
S. Bepari ◽  
R. Stevens-Boyd ◽  
N. Mohammad ◽  
Xin Li ◽  
R. Abrokwah ◽  
...  
2020 ◽  
Vol 358 ◽  
pp. 303-315 ◽  
Author(s):  
Nafeezuddin Mohammad ◽  
Richard Y. Abrokwah ◽  
Robert G. Stevens-Boyd ◽  
Shyam Aravamudhan ◽  
Debasish Kuila

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 872 ◽  
Author(s):  
Mohammad ◽  
Bepari ◽  
Aravamudhan ◽  
Kuila

Fischer–Tropsch (FT) synthesis was carried out in a 3D printed stainless steel (SS) microchannel microreactor using bimetallic Co-Ru catalysts on three different mesoporous silica supports. CoRu-MCM-41, CoRu-SBA-15, and CoRu-KIT-6 were synthesized using a one-pot hydrothermal method and characterized by Brunner–Emmett–Teller (BET), temperature programmed reduction (TPR), SEM-EDX, TEM, and X-ray photoelectron spectroscopy (XPS) techniques. The mesoporous catalysts show the long-range ordered structure as supported by BET and low-angle XRD studies. The TPR profiles of metal oxides with H2 varied significantly depending on the support. These catalysts were coated inside the microchannels using polyvinyl alcohol and kinetic performance was evaluated at three different temperatures, in the low-temperature FT regime (210–270 °C), at different Weight Hourly Space Velocity (WHSV) in the range of 3.15–25.2 kgcat.h/kmol using a syngas ratio of H2/CO = 2. The mesoporous supports have a significant effect on the FT kinetics and stability of the catalyst. The kinetic models (FT-3, FT-6), based on the Langmuir–Hinshelwood mechanism, were found to be statistically and physically relevant for FT synthesis using CoRu-MCM-41 and CoRu-KIT-6. The kinetic model equation (FT-2), derived using Eley–Rideal mechanism, is found to be relevant for CoRu-SBA-15 in the SS microchannel microreactor. CoRu-KIT-6 was found to be 2.5 times more active than Co-Ru-MCM-41 and slightly more active than CoRu-SBA-15, based on activation energy calculations. CoRu-KIT-6 was ~3 and ~1.5 times more stable than CoRu-SBA-15 and CoRu-MCM-41, respectively, based on CO conversion in the deactivation studies.


2020 ◽  
Vol 608 ◽  
pp. 117838
Author(s):  
S. Bepari ◽  
Xin Li ◽  
R. Abrokwah ◽  
N. Mohammad ◽  
M. Arslan ◽  
...  

Author(s):  
Nafeezuddin Mohammad ◽  
Omar M. Basha ◽  
Sujoy Bepari ◽  
Richard Y. Abrokwah ◽  
Vishwanath Deshmane ◽  
...  

Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.


Author(s):  
J. A. Korbonski ◽  
L. E. Murr

Comparison of recovery rates in materials deformed by a unidimensional and two dimensional strains at strain rates in excess of 104 sec.−1 was performed on AISI 304 Stainless Steel. A number of unidirectionally strained foil samples were deformed by shock waves at graduated pressure levels as described by Murr and Grace. The two dimensionally strained foil samples were obtained from radially expanded cylinders by a constant shock pressure pulse and graduated strain as described by Foitz, et al.


Author(s):  
R. Gonzalez ◽  
L. Bru

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.


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