Regeneration of Pristine HZSM-5 Extrudates during the Production of Deeply-Deoxygenated Bio-oil from Ex-Situ Catalytic Fast Pyrolysis of Biomass in a Bench-Scale Fluidised-Bed Reactor

Ex-situ catalytic fast pyrolysis (ex-CFP) of biomass applying ZSM-5 catalysts is an effective method for deoxygenating the pyrolysis vapour, thus producing low-oxygen bio-oil in a single step. The catalysts deactivate...

Removal of Aniline and Benzothiazole Wastewaters Using an Efficient MnO2/GAC Catalyst in a Photocatalytic Fluidised Bed Reactor

This work presents an efficient method for treating industrial wastewater containing aniline and benzothiazole, which are refractory to conventional treatments. A combination of heterogeneous photocatalysis operating in a fluidised bed reactor is studied in order to increase mass transfer and reduce reaction times. This process uses a manganese dioxide catalyst supported on granular activated carbon with environmentally friendly characteristics. The manganese dioxide composite is prepared by hydrothermal synthesis on carbon Hydrodarco® 3000 with different active phase ratios. The support, the metal oxide, and the composite are characterised by performing Brunauer, Emmett, and Teller analysis, transmission electron microscopy, X-ray diffraction analysis, X-ray fluorescence analysis, UV–Vis spectroscopy by diffuse reflectance, and Fourier transform infrared spectroscopy in order to evaluate the influence of the metal oxide on the activated carbon. A composite of MnO2/GAC (3.78% in phase α-MnO2) is obtained, with a 9.4% increase in the specific surface of the initial GAC and a 12.79 nm crystal size. The effect of pH and catalyst load is studied. At a pH of 9.0 and a dose of 0.9 g L−1, a high degradation of aniline and benzothiazole is obtained, with an 81.63% TOC mineralisation in 64.8 min.

Gasification Kinetics of Victorian Brown Coal-Derived Char in Fluidised Bed Reactor

In a chemical looping combustion (CLC) system, gasification kinetics of char holds immense importance being the rate-limiting reaction in the fuel reactor. This paper studied the gasification kinetics of char derived from Victorian Brown Coal (VBC) in a fluidised bed reactor which mimics the fuel reactor conditions of a CLC process. Mass of char, char particle size and gas flow conditions were optimised to ensure the gasification reaction free from mass transfer limitations. Effect of oxygen carrier, hematite, being the bed material was also studied. The experiments were conducted in the temperature range of 800C-950C, which is a typical range for fuel reactor. The experimental results were modelled with the help of grain model (GM) and random pore model (RPM) to analyse the kinetic parameters. Activation energy was found to be around 177 kJ/mol in sand bed and 175.5 kJ/mol in the hematite bed. Reaction in hematite bed was found to be 42% faster on average compared to the reaction in a sand bed. Fastest total conversion of char took as low as 4.1 minutes in hematite bed at 950C. While catalytic effect of hematite was ruled out due to insignificant change in activation energy, it was concluded that increase in CO2 partial pressure at the vicinity of char particle enhanced the reaction rate in the case of hematite bed. This study has generated relevant information for the CLC of Victorian Brown Coal with hematite as the oxygen carrier.

A theoretical analysis of the burn-out times of an isothermal particle of coal char under air-firing, gasification and oxyfuel combustion in fluidised beds

<p></p><p>The combustion of coal in air, its gasification with carbon dioxide, and oxyfuel combustion in oxygen/carbon dioxide mixtures was studied at high process temperatures in a bubbling fluidised bed reactor where burning is controlled by external mass transfer conditions. Theoretical analysis of the burn-out times of an isothermal particle of coal char in air is provided for the case where a fraction of carbon monoxide is oxidized close to the char particle. Burn-out time equations are provided for the gasification of char in carbon dioxide. Both burn-out time equations are compared to analytical equations derived for the oxy-fuel combustion of char particles in oxygen/carbon dioxide mixtures. The results are particularly relevant for retrofitting existing bubbling fluidised bed reactors for sustainable energy generation to meet global warming targets. </p><p></p>

A Simple Theoretical Analysis of the Burn-out Times of an Isothermal Particle of Coal Char Under Air-Firing, Gasification and Oxyfuel Combustion in Fluidised Beds

<p></p><p>Coal combustion in air, gasification with carbon dioxide, and oxyfuel combustion in oxygen/carbon dioxide mixtures was studied at high process temperatures in a bubbling fluidised bed reactor where burning is controlled by external mass transfer conditions. Theoretical analysis of the burn-out times of an isothermal particle of coal char in air is provided for the case where a fraction of carbon monoxide is oxidized close to the char particle. Burn-out time equations are provided for the gasification of char in carbon dioxide. Both burn-out time equations are compared to analytical equations derived for the oxy-fuel combustion of char particles in oxygen/carbon dioxide mixtures. The results are particularly relevant for retrofitting existing bubbling fluidised bed reactors for clean energy generation to meet global warming targets.</p><p></p>

A Simple Theoretical Analysis of the Burn-out Times of an Isothermal Particle of Coal Char Under Air-Firing, Gasification and Oxyfuel Combustion in Fluidised Beds

<p></p><p>Coal combustion in air, gasification with carbon dioxide, and oxyfuel combustion in oxygen/carbon dioxide mixtures was studied at high process temperatures in a bubbling fluidised bed reactor where burning is controlled by external mass transfer conditions. Theoretical analysis of the burn-out times of an isothermal particle of coal char in air is provided for the case where a fraction of carbon monoxide is oxidized close to the char particle. Burn-out time equations are provided for the gasification of char in carbon dioxide. Both burn-out time equations are compared to analytical equations derived for the oxy-fuel combustion of char particles in oxygen/carbon dioxide mixtures. The results are particularly relevant for retrofitting existing bubbling fluidised bed reactors for clean energy generation to meet global warming targets.</p><p></p>

A Simple Theoretical Analysis of the Burn-out Times of an Isothermal Particle of Coal Char Under Air-Firing, Gasification and Oxyfuel Combustion in Fluidised Beds

<p>Coal combustion in air, gasification with carbon dioxide and oxyfuel combustion in oxygen/carbon dioxide mixtures was studied at high process temperatures in a bubbling fluidised bed reactor where burning is controlled by external mass transfer conditions is considered. Theoretical analysis of the burn-out times of an isothermal particle of coal char in air is provided for the case where a fraction of carbon monoxide is oxidized close to the char particle. Burn-out time equations are provided for the gasification of char in carbon dioxide. Both burn-out time equations are compared to analytical equations derived for the oxy-fuel combustion of char particles in oxygen/carbon dioxide mixtures. </p>

A Simple Theoretical Analysis of the Burn-out Times of an Isothermal Particle of Coal Char Under Air-Firing, Gasification and Oxyfuel Combustion in Fluidised Beds

<p>Coal combustion in air, gasification with carbon dioxide and oxyfuel combustion in oxygen/carbon dioxide mixtures was studied at high process temperatures in a bubbling fluidised bed reactor where burning is controlled by external mass transfer conditions. Theoretical analysis of the burn-out times of an isothermal particle of coal char in air is provided for the case where a fraction of carbon monoxide is oxidized close to the char particle. Burn-out time equations are provided for the gasification of char in carbon dioxide. Both burn-out time equations are compared to analytical equations derived for the oxy-fuel combustion of char particles in oxygen/carbon dioxide mixtures. </p>