Dynamic analysis of removal and selective oxidation of H2S to elemental sulfur over Cu–V and Cu–V–Mo mixed oxides in a fixed bed reactor

2004 ◽  
Vol 59 (19) ◽  
pp. 4001-4009 ◽  
Author(s):  
Sena Yasyerli ◽  
Gulsen Dogu ◽  
Irfan Ar ◽  
Timur Dogu
Keyword(s):  
Dynamic Analysis ◽  
Selective Oxidation ◽  
Elemental Sulfur ◽  
Mixed Oxides ◽  
Fixed Bed ◽  
Fixed Bed Reactor

Highly selective oxidation of benzyl alcohol over Pt-sulphated zirconia supported on SBA-15 catalyst by using a high-pressure fixed bed reactor

Polyhedron ◽  
2018 ◽  
Vol 155 ◽  
pp. 390-397 ◽  
Author(s):  
P. Tamizhdurai ◽  
Subramanian Sakthinathan ◽  
P. Santhana Krishnan ◽  
A. Ramesh ◽  
A. Abilarasu ◽  
...  
Keyword(s):  
High Pressure ◽  
Benzyl Alcohol ◽  
Selective Oxidation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Sulphated Zirconia ◽  
Oxidation Of Benzyl Alcohol

scholarly journals Aldol Condensation of Cyclohexanone and Furfural in Fixed-Bed Reactor

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1068
Author(s):  
Zdeněk Tišler ◽  
Pavla Vondrová ◽  
Kateřina Hrachovcová ◽  
Kamil Štěpánek ◽  
Romana Velvarská ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Heterogeneous Catalysts ◽  
Mixed Oxides ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Catalyst Activity ◽  
Fixed Bed ◽  
Chemical Properties ◽  
Fixed Bed Reactor ◽  
Molar Ratio

Aldol condensation reaction is usually catalysed using homogeneous catalysts. However, the heterogeneous catalysis offers interesting advantages and the possibility of cleaner biofuels production. Nowadays, one of the most used kinds of heterogeneous catalysts are hydrotalcites, which belong to a group of layered double hydroxides. This paper describes the aldol condensation of cyclohexanone (CH) and furfural (F) using Mg/Al mixed oxides and rehydrated mixed oxides in order to compare the catalyst activity after calcination and rehydration, as well as the possibility of its regeneration. The catalysts were synthesized by calcination and subsequent rehydration of the laboratory-prepared and commercial hydrotalcites, with Mg:Al molar ratio of 3:1. Their structural and chemical properties were determined by several analytical methods (inductively coupled plasma analysis (ICP), X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), specific surface area (BET), thermogravimetric analysis (TGA), temperature programmed desorption (TPD)). F-CH aldol condensation was performed in a continuous fixed-bed reactor at 80 °C, CH:F = 5:1, WHSV 2 h−1. The rehydrated laboratory-prepared catalysts showed a 100% furfural conversion for more than 55 h, in contrast to the calcined ones (only 24 h). The yield of condensation products FCH and F2CH was up to 68% and 10%, respectively. Obtained results suggest that Mg/Al mixed oxides-based heterogeneous catalyst is suitable for use in the aldol condensation reaction of furfural and cyclohexanone in a fixed-bed reactor, which is an interesting alternative way to obtain biofuels from renewable sources.

The Effect of Regeneration Conditions on the Properties of CeO2 Desulfurization Sorbent in SO2 Atmosphere

2017 ◽  
Vol 896 ◽  
pp. 155-161
Author(s):  
Lei Yang ◽  
Shang Guan Ju ◽  
Hui Qing Wang ◽  
Jia An ◽  
Jun Ming Yu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Elemental Sulfur ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Regeneration Condition ◽  
Main Components ◽  
Scanning Electron

CeO2 desulfurization sorbent was prepared by calcination of Ce(NO3)3 ● 6H2O and the effect of regeneration conditions on its properties in SO2 atmosphere was investigated in a fixed bed reactor. The regeneration conversion and the yield of elemental sulfur for CeO2 desulfurization sorbent were tested and calculated. And the composition and the morphology of CeO2 desulfurization sorbent before and after regeneration were obtained by X-ray diffraction and scanning electron microscope. It was found that the main components of the regeneration products of Ce2O desulfurization sorbent were solid CeO2 and gaseous elemental S in SO2 atmosphere. The optimum regeneration condition of CeO2 desulfurization sorbent is that the regeneration temperature of 750 °C and the SO2 concentration of 4.25 %, under which the CeO2 desulfurization sorbent shows the higher regeneration conversion of 96 % and the yield of elemental sulfur of 68.95 wt. %.

Efficient selective oxidation of benzyl alcohol with oxygen in a continuous fixed bed reactor over NiGa hydrotalcite derived catalyst

2020 ◽  
Vol 592 ◽  
pp. 117417 ◽  
Author(s):  
Weiyou Zhou ◽  
Guanhu Chen ◽  
Binxun Yu ◽  
Jiacheng Zhou ◽  
Junfeng Qian ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Selective Oxidation ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Oxidation Of Benzyl Alcohol

scholarly journals Effect of Cesium and Phosphate Addition to Mo/V/W Mixed Oxide Catalysts for the Gas Phase Oxidation of Methacrolein to Methacrylic Acid

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 231
Author(s):  
Maximilian Sennerich ◽  
Peter G. Weidler ◽  
Stefan Heißler ◽  
Bettina Kraushaar-Czarnetzki
Keyword(s):  
Methacrylic Acid ◽  
Mixed Oxide ◽  
Mixed Oxides ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Long Term Stability ◽  
Mixed Oxide Catalysts ◽  
Phosphate Ions ◽  
Reaction Unit

The present study investigates modified Mo/V/W mixed oxides as a possible alternative for state of the art heteropoly acid catalysts (HPA) in the partial oxidation of methacrolein (MAC) to methacrylic acid (MAA). Even though HPAs show an excellent activity and MAA selectivity, their long-term stability is unsatisfying, rendering the catalyst inoperable after runtimes of roughly 6 months. Mo/V/W mixed oxides consisting of M1 and a hexagonal (Mo,V,W)Ox-phase (h-phase) in varying proportions were modified by impregnation with aqueous solutions containing cesium and phosphate ions. All samples were characterized with respect to specific surface area, crystallinity, elemental and phase composition. The catalytic performance in the oxidation of MAC to MAA was investigated using a continuously operated reaction unit with tubular fixed bed reactor. Impregnation with cesium and phosphate ions and subsequent heating triggers the transformation of the mixed oxide into a Keggin-type HPA, whereby the h-phase is more reactive than M1. The transformation into HPA is accompanied by a change in the catalytic properties, i.e., the selectivity to MAA is considerably improved. Compared to HPA synthesized directly, however, the HPA samples obtained by transformation of mixed oxides exhibit no advantages, be it with respect to activity, MAA selectivity or stability.

The Regeneration Properties of Manganese Oxide Sorbent under SO2 Atmosphere

2016 ◽  
Vol 859 ◽  
pp. 140-145 ◽  
Author(s):  
Hui Qing Wang ◽  
Shang Guan Ju ◽  
Li Ping Liu ◽  
Xiao Wei Zhao ◽  
Jie Mi
Keyword(s):  
Manganese Oxide ◽  
Photoelectron Spectroscopy ◽  
Elemental Sulfur ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value ◽  
Regeneration Mechanism ◽  
Effects Of Temperature

The effects of temperature and concentration of sulfur dioxide on regeneration behavior of manganese oxide sorbent were studied in a fixed-bed reactor. The sorbents were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. Subsequently, the regeneration mechanism was inferred and the yield of export elemental sulfur was calculated. The study shows that, the major regeneration products are Mn3O4, MnSO4 and a small amount of elemental sulfur under SO2 atmosphere.The sulfate can be converted to Mn3O4and Mn2O3 at 800 °C under N2 atmosphere. The elemental sulfur productivity increases with the increase of temperature and concentration of sulfur dioxide.The regeneration conversion attains maximum value (68%) at 800 °C under the atmosphere of 1.68% SO2, and the productivity of elemental sulfur reaches to maximum value (29%) under the conditions.

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