Jinhu Wu

From biomass to advanced bio-fuel by catalytic pyrolysis/hydro-processing: Hydrodeoxygenation of bio-oil derived from biomass catalytic pyrolysis

Compared hydrodeoxygenation experimental studies of both model compounds and real bio-oil derived from biomass fast pyrolysis and catalytic pyrolysis was carried out over two different supported Pt catalysts. For the model compounds, the deoxygenation degree of dibenzofuran was higher than that of cresol and guaiacol over both Pt/Al(2)O(3) and the newly developed Pt supported on mesoporous zeolite (Pt/MZ-5) catalyst, and the deoxygenation degree of cresol over Pt/MZ-5 was higher than that over Pt/Al(2)O(3). The results indicated that hydrodeoxygenation become much easier upon oxygen reduction. Similar to model compounds study, the hydrodeoxygenation of the real bio-oil derived from catalytic pyrolysis was much easier than that from fast pyrolysis over both Pt catalysts, and the Pt/MZ-5 again shows much higher deoxygenation ability than Pt/Al(2)O(3). Clearly synergy between catalytic pyrolysis and bio-oil hydro-processing was found in this paper and this finding will lead an advanced biofuel production pathway in the future.

TG/FTIR analysis on co-pyrolysis behavior of PE, PVC and PS.

The pyrolysis and co-pyrolysis behaviors of polyethylene (PE), polystyrene (PS) and polyvinyl chloride (PVC) under N2 atmosphere were analyzed by Thermal gravimetric/Fourier transform infrared (TG/FTIR). The volatile products were analyzed to investigate the interaction of the plastic blends during the thermal decomposition process. The TGA results showed that the thermal stability increased followed by PVC, PS and PE. The pyrolysis process of PE was enhanced when mixed with PS. However, PS was postponed when mixed with PVC. As for PE and PVC, mutual block was happened when mixed together. The FTIR results showed that the free radical of the decomposition could combine into a stable compound. When PE mixed with PVC or PS, large amount of unsaturated hydrocarbon groups existed in products while the content of alkynes was decreased. The methyl (-CH3) and methylene (-CH2-) bonds were disappeared while PVC mixed with PE.

Multi-Gaussian-DAEM-reaction model for thermal decompositions of cellulose, hemicellulose and lignin: comparison of N2 and CO2 atmosphere.

Thermal decompositions of three components of biomass (cellulose, hemicellulose and lignin) were studied using nonisothermal thermogravimetric analysis (TGA) under both oxidative and inert atmospheres at a heating rate of 10 K min(-1). The multi-Gaussian-distributed activation energy model (DAEM)-reaction model was first developed to describe thermal decomposition behaviors of three components. Results showed that the presence of CO₂ enhanced the thermal decompositions of three components in high temperature range, but made little difference in low temperature range. Decomposition behaviors under CO₂ were analyzed by the two-stage reaction mechanism corresponding to the pyrolysis process of original materials and the gasification process of char. During gasification stage, CO₂ was reduced to CO, which provided a possibility of a reduction in greenhouse gas emissions. In addition, more CO was produced, and therefore the thermal value of gas was improved. The findings imply that CO₂ gasification technology of biomass has great research significance.

Gasification kinetic analysis of the three pseudocomponents of biomass-cellulose, semicellulose and lignin

The gasification kinetic analysis of the three pseudocomponents (hemicellulose, cellulose and lignin) of biomass decomposition in the agent of CO2 were investigated. The Multi-peaks method was used to fit the Gaussian distribution model of DTG curves. The Friedman method was used to estimate the effective Eα, and the master plot method was used for the determination of the kinetic model. The results showed that there were two reaction stages for semi-cellulose and lignin. The DTG curves of semicellulose and lignin cannot be fitted by Gaussian distribution model. The Eα were ranged from 80 to 220kJmol(-1) for the three pseudocomponents. The Fn model could describe the kinetic process of stage I of semi-cellulose decomposition. Both cellulose and stage II of semicellulose decomposition could be described by An model and the two reaction stages of the lignin were fitted the Rn model very well.

Hydrodeoxygenation of bio-oil over Pt-based supported catalysts: importance of mesopores and acidity of the support to compounds with different oxygen contents

The importance of the acidity and mesoporous structure to the hydrodeoxygenation activity of catalysts for bio-oil upgrading was investigated. By testing three model bio-oil compounds, we showed that catalysts with a strong acidity (e.g. ZSM-5) have a high hydrodeoxygenation activity, while the mesoporous structure of the support can further improve the catalytic performance of ZSM-5.

Thermogravimetric study and kinetic analysis of dried industrial sludge pyrolysis

Thermogravimetric experiments of two different industrial sludge samples were carried out with non-isothermal temperature programs. The results indicated that the pyrolysis process contains three obvious stages and the main decomposition reaction occurred in the range of 200-600°C. The distributed activation energy model (DAEM) was also proposed describing equally well the pyrolysis behavior of the samples. The calculated activation energy was ranged from 170 to 593kJ/mol and 125 to 756kJ/mol for SLYG (sludge sample from chemical fiber factory) and SQD (sludge sample from woody industry), respectively. The reliability of this model not only provided good fit for all experiments, but also allowed accurate extrapolations to relative higher heating rates. Besides, the FTIR measurement was also used to further understand the relationship between pyrolysis behavior and chemical structures for industrial sludge.

Kinetic and energy production analysis of pyrolysis of lignocellulosic biomass using a three-parallel Gaussian reaction model.

The kinetic and energy productions of pyrolysis of a lignocellulosic biomass were investigated using a three-parallel Gaussian distribution method in this work. The pyrolysis experiment of the pine sawdust was performed using a thermogravimetric-mass spectroscopy (TG-MS) analyzer. A three-parallel Gaussian distributed activation energy model (DAEM)-reaction model was used to describe thermal decomposition behaviors of the three components, hemicellulose, cellulose and lignin. The first, second and third pseudocomponents represent the fractions of hemicellulose, cellulose and lignin, respectively. It was found that the model is capable of predicting the pyrolysis behavior of the pine sawdust. The activation energy distribution peaks for the three pseudo-components were centered at 186.8, 197.5 and 203.9kJmol(-1) for the pine sawdust, respectively. The evolution profiles of H2, CH4, CO, and CO2 were well predicted using the three-parallel Gaussian distribution model. In addition, the chemical composition of bio-oil was also obtained by pyrolysis-gas chromatography/mass spectrometry instrument (Py-GC/MS).

Corn stalks char from fast pyrolysis as precursor material for preparation of activated carbon in fluidized bed reactor

Corn stalks char from fast pyrolysis was activated by physical and chemical activation process in a fluidized bed reactor. The structure and morphology of the carbons were characterized by N2 adsorption and SEM. Effects of activation time and activation agents on the structure of activation carbon were investigated. The physically activated carbons with CO2 have BET specific surface area up to 880 m(2)/g, and exhibit microporous structure. The chemically activated carbons with H3PO4 have BET specific surface area up to 600 m(2)/g, and exhibit mesoporous structure. The surface morphology shows that physically activated carbons exhibit fibrous like structure in nature with long ridges, resembling parallel lines. Whereas chemically activated carbons have cross-interconnected smooth open pores without the fibrous like structure.

TG-MS analysis and kinetic study for thermal decomposition of six representative components of municipal solid waste under steam atmosphere

Thermal decomposition of six representative components of municipal solid waste (MSW, including lignin, printing paper, cotton, rubber, polyvinyl chloride (PVC) and cabbage) was investigated by thermogravimetric-mass spectroscopy (TG-MS) under steam atmosphere. Compared with TG and derivative thermogravimetric (DTG) curves under N2 atmosphere, thermal decomposition of MSW components under steam atmosphere was divided into pyrolysis and gasification stages. In the pyrolysis stage, the shapes of TG and DTG curves under steam atmosphere were almost the same with those under N2 atmosphere. In the gasification stage, the presence of steam led to a greater mass loss because of the steam partial oxidation of char residue. The evolution profiles of H2, CH4, CO and CO2 were well consistent with DTG curves in terms of appearance of peaks and relevant stages in the whole temperature range, and the steam partial oxidation of char residue promoted the generation of more gas products in high temperature range. The multi-Gaussian distributed activation energy model (DAEM) was proved plausible to describe thermal decomposition behaviours of MSW components under steam atmosphere.

La0.6Sr0.4Co0.2Fe0.8O3−δ hollow fibre membrane performance improvement by coating of Ba0.5Sr0.5Co0.9Nb0.1O3−δ porous layer

The oxygen permeation performance of perovskite La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) hollow fibre membranes was enhanced by surface modification via coating of a Ba0.5Sr0.5Co0.9Nb0.1O3−δ (BSCN) porous layer. The hollow fibres were characterized by XRD, SEM and EDS elemental mapping and tested for air separation. Experimental results revealed that the BSCN porous layer had significantly improved the oxygen permeation flux of the coated LSCF hollow fibre membranes. Operated at 950 °C and under the oxygen pressure gradient of the air/sweep gas, the maximum oxygen permeation flux of 1.92 mL cm−2 min−1 was achieved after the hollow fibre membrane was coated by a BSCN porous layer on both outer and inner surfaces. In addition, the modified membrane showed high oxygen permeation stability under the investigated operational conditions.