scholarly journals Catalytic Properties and Recycling of NiFe2O4 Catalyst for Hydrogen Production by Supercritical Water Gasification of Eucalyptus Wood Chips

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4553 ◽  
Author(s):  
Ane Caroline Pereira Borges ◽  
Jude Azubuike Onwudili ◽  
Heloysa Andrade ◽  
Carine Alves ◽  
Andrew Ingram ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Biomass Conversion ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Wood Chips ◽  
Nickel Iron ◽  
Eucalyptus Wood ◽  
Supercritical Water Gasification ◽  
Temperature Programmed ◽  
Reaction Cycles

Nickel iron oxide (NiFe2O4) catalyst was prepared by the combustion reaction method and characterized by XRD, N2 adsorption/desorption, thermogravimetric analysis (TG), and temperature programmed reduction (TPR). The catalyst presented a mixture of oxides, including the NiFe2O4 spinel and specific surface area of 32.4 m2 g−1. The effect of NiFe2O4 catalyst on the supercritical water gasification (SCWG) of eucalyptus wood chips was studied in a batch reactor at 450 and 500 °C without catalyst and with 1.0 g and 2.0 g of catalyst and 2.0 g of biomass for 60 min. In addition, the recyclability of the catalyst under the operating conditions was also tested using recovered and recalcined catalysts over three reaction cycles. The highest amount of H2 was 25 mol% obtained at 450 °C, using 2 g of NiFe2O4 catalyst. The H2 mol% was enhanced by 45% when compared to the non-catalytic test, showing the catalytic activity of NiFe2O4 catalyst in the WGS and the steam reforming reactions. After the third reaction cycle, the results of XRD demonstrated formation of coke which caused the deactivation of the NiFe2O4 and consequently, a 13.6% reduction in H2 mol% and a 5.6% reduction in biomass conversion.

scholarly journals Supercritical Water Gasification of Eucalyptus Wood Chips Using NiFe2O4 as a Catalyst

2018 ◽  
Vol 64 ◽  
pp. 01002 ◽  
Author(s):  
Caroline Pereira Borges Ane ◽  
A. Onwuidili Jude ◽  
Tondo Alves Carine ◽  
Ingram Andrew ◽  
Martins Carvalho Andrade Heloysa ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Supercritical Water ◽  
Batch Reactor ◽  
Wood Chips ◽  
Solid Residue ◽  
Liquid Sample ◽  
Eucalyptus Wood ◽  
Experimental Parameters ◽  
Gas Products ◽  
Supercritical Water Gasification

In this work, the supercritical water gasification of eucalyptus wood chips has been investigated in relation to reaction temperature and presence of catalyst. Experiments were performed in a batch reactor at 450 ºC and 500 ºC with two different feed concentrations. This work wanted to evaluate mainly the gases were formed during the reactions. The gas products were analysed by gas chromatography. According to the results, it was found that eucalyptus wood chips reacted to form mainly H2, CH4 gases with little yield of CO2. Increasing the reaction temperature beyond 500 ºC led to the increasing production of both CH4 (around 31.1 mol%) and H2 (up to 38 mol%) gases and the liquid sample and solid residue have decreased. Generally, this work suggests that the SCWG has improved significantly the production of H2 but more experiments still necessary to verify the effects of other experimental parameters and to characterise the liquid sample and solid residue.

scholarly journals Catalytic supercritical water gasification of eucalyptus wood chips in a batch reactor

Fuel ◽  
2019 ◽  
Vol 255 ◽  
pp. 115804 ◽  
Author(s):  
A.C.P. Borges ◽  
J.A. Onwudili ◽  
H.M.C. Andrade ◽  
C.T. Alves ◽  
A. Ingram ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Batch Reactor ◽  
Wood Chips ◽  
Eucalyptus Wood ◽  
Supercritical Water Gasification

scholarly journals Inference of Reaction Kinetics for Supercritical Water Heavy Oil Upgrading with a Two-phase Stirred Reactor Model

2021 ◽  
Author(s):  
Ashwin Raghavan ◽  
Ping He ◽  
Ahmed Ghoniem
Keyword(s):  
Reaction Kinetics ◽  
Supercritical Water ◽  
Heavy Oil ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Water Phase ◽  
Reactor Model ◽  
Two Phase ◽  
Stirred Reactor ◽  
Heavy Oil Upgrading

We present the development and application of a two-phase stirred reactor model for heavy oil upgrading in the presence of supercritical water (SCW), with coupled phase-specific thermolysis reaction kinetics and multicomponent hydrocarbon water phase equilibrium. We demonstrate the inference of oil and water phase kinetics parameters for a compact lumped reaction kinetics model through the application of this model to two different sets of batch reactor experiments reported in the literature. We infer that, though SCW can suppress the formation of newer polynuclear aromatics (PNA) from distillate range species, it is broadly ineffective in deterring the combination of pre-existing PNA fragments in the oil feed. Quantification of the conversion to distillate liquids before the onset of coke formation helps arrive at a clearer conclusion on whether the use of SCW in the batch reactor leads to better product outcomes for different oil feeds and operating conditions.

scholarly journals Analysis of operational issues in hydrothermal liquefaction and supercritical water gasification processes: a review

2021 ◽  
Author(s):  
Niloufar Ghavami ◽  
Karhan Özdenkçi ◽  
Gabriel Salierno ◽  
Margareta Björklund-Sänkiaho ◽  
Cataldo De Blasio
Keyword(s):  
Supercritical Water ◽  
Biomass Conversion ◽  
Hydrothermal Liquefaction ◽  
Production Costs ◽  
Process Conditions ◽  
Operation Conditions ◽  
High Production ◽  
Supercritical Water Gasification ◽  
Operational Issues ◽  
Conversion Technologies

AbstractBiomass is often referred to as a carbon–neutral energy source, and it has a role in reducing fossil fuel depletion. In addition, biomass can be converted efficiently into various forms of biofuels. The biomass conversion processes involve several thermochemical, biochemical, and hydrothermal methods for biomass treatment integration. The most common conversion routes to produce biofuels include pyrolysis and gasification processes. On the other hand, supercritical water gasification (SCWG) and hydrothermal liquefaction (HTL) are best suitable for converting biomass and waste with high moisture content. Despite promising efficiencies, SCWG and HTL processes introduce operational issues as obstacles to the industrialization of these technologies. The issues include process safety aspects due to operation conditions, plugging due to solid deposition, corrosion, pumpability of feedstock, catalyst sintering and deactivation, and high production costs. The methods to address these issues include various reactor configurations to avoid plugging and optimizing process conditions to minimize other issues. However, there are only a few studies investigating the operational issues as the main scope, and reviews are seldomly available in this regard. Therefore, further research is required to address operational problems. This study reviews the main operational problems in SCWG and HTL. The objective of this study is to enhance the industrialization of these processes by investigating the operational issues and the potential solutions, i.e., contributing to the elimination of the obstacles. A comprehensive study on the operational issues provides a holistic overview of the biomass conversion technologies and biorefinery concepts to promote the industrialization of SCWG and HTL.

Dynamics of phosphorus and organic substrates in anaerobic and aerobic phases of a sequencing batch reactor

1994 ◽  
Vol 30 (6) ◽  
pp. 237-246 ◽  
Author(s):  
A. Carucci ◽  
M. Majone ◽  
R. Ramadori ◽  
S. Rossetti
Keyword(s):  
Sequencing Batch Reactor ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
General Assumption ◽  
Organic Substrate ◽  
Operating Conditions ◽  
Phosphate Removal ◽  
Substrate Uptake ◽  
Organic Substrates ◽  
Polyphosphate Metabolism

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch reactor (SBR). The synthetic feed used was based on peptone and glucose as organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991). The experimental work was divided into two runs, each characterized by different operating conditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulating and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called “G bacteria”. The results obtained seem to be inconsistent with the general assumption that the G bacteria are characterized by anaerobic substrate uptake not connected with any polyphosphate metabolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as organic substrates show that the role of acetate in the biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.

Supercritical water gasification of food waste: Effect of parameters on hydrogen production

2020 ◽  
Vol 45 (29) ◽  
pp. 14744-14755 ◽  
Author(s):  
Wei Su ◽  
Changqing Cai ◽  
Ping Liu ◽  
Wei Lin ◽  
Baorui Liang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Food Waste ◽  
Supercritical Water ◽  
Supercritical Water Gasification
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