Chang Qing Dong

Aerobic Production of Butanol with Bacillus amyloliquefaciens NELB-12

n-butanol is a basic chemical compound with lower volatility, intersolubility and higher heating value, making it suitable to be used as a potential alternative biofuel. One butanol producing strain was isolated from soil and identified by 16S rDNA sequencing. Two universal primers (27F, 1492R) were used. Squence analysis indicated 16S rDNA sequence (Accession Number KF418240) of this strain was 99% identical to that of Bacillus amyloliquefaciens. This strain was designed as Bacillus amyloliquefaciens NELB-12. Optimaization of fermentation medium composition and fermentation conditions were carried out. The optimal medium main components were 30 g/l starch, 4 g/l ammonium nitrate, and 30 g/l beef extract. The optimal fermentation cultured with working volume of 120 ml in 250 ml flask at pH 6.5, 39°C, and 100 rpm. Bacillus NELB-12 could produce butanol at higher concentration that reached 8.9 g/l with a total ABE of 12.7 g/l and showed a high butanol tolerance. B. amyloliquefaciens NELB-12 is considered as an economical and cost effective potential producer for butanol industry.

Activity of Fe2O3 and its Effect on Co Oxidation in the Chemical Looping Combustion: An Theoretical Account

The study focuses on Fe2O3 oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were performed to detect the performance of Fe2O3 during CLC of CO. Reaction mechanism between CO and Fe2O3 was explored in details, which demonstrates that Fe2O3 with more low-fold O atoms on the surface could promote the activity of the Fe-based oxygen carrier in CLC system.

Theoretical Study on Reactivity of Fe-Based Oxygen Carrier with CH4 during Chemical Looping Combustion

The mechanism of interaction between CH4 and oxygen carrier surface was studied using density functional theory (DFT) calculations. The adsorption energy of CH4 on Fe2O3 surface Fe bridge site is the highest, indicating Fe bridge site adsorption is the most stable, and O top site follows. The CH4-Fe2O3 surface reaction path was inferred as: (1) the generation of hydroxyl radical, (2) the interaction between hydroxyl radical and CH4 with its intermediates in chain, and (3) the generation of H2O and CO2 through oxidation. The research will provide guidance for the interaction mechanism between CH4 and oxygen carrier surface and the optimization of CLC macroscopic reaction kinetics.

Effect of Co-Doping on Iron-Based Oxygen Carrier for CO Oxidation in Chemical Looping Combustion

This paper focuses on theoretical research of Co-doped Fe-based oxygen carrier for CO oxidation in chemical-looping combustion (CLC) system. Density functional theory (DFT) calculations were carried out to study of interaction between CO molecules and CoO/Fe2O3 cluster, it is found that dissociation of O atom through breaking of Fe-O bonds in the Fe2O3 system is the key step for CO oxidation reaction, and Low-fold O atoms in Fe2O3 system could more readily dissociate from external surface. Moreover, the presence of CoO in Fe2O3 could decrease activation energy and reaction energy of CO/Co-Fe2O3 system, hence the reaction between CO and Fe2O3 is promoted.

Theoretical Study on Reactivity of Cu-Based Oxygen Carrier for CO Chemical Looping Combustion

The reaction of Cu-based oxygen carrier with CO during chemical looping combustion was studies using density functional theory (DFT) calculations in this paper. It was found that CO2 is formed after CO chemically adsorbed onto CuO surface and it exhibits strong localization properties. Energy barrier with regard to the overall reaction is 1.947 eV with overall reaction energy of-3.686 eV, indicating the overall reaction is an exothermic process. As can be figured out from the geometries of the stable structures, after the physical adsorption of CO on CuO surface, 1.947 eV is needed to jump to the transition state, and the nearest distance between CO and the surface is 1.542 Å with bond angle of 155.381°, C-O bond has stretched to 1.151 Å from 1.147 Å. With further interaction between CO and CuO surface, nearly linear structure O-C-O group is formed with bond angle of 179.177° and almost symmetric C-O bond distance, which was thought to be the formation of CO2.

Overview of Bio-Oil Upgrading via Catalytic Cracking

Fast pyrolysis of biomass to produce bio-oil is an important technology to utilize lignocellulosic biomass, because the liquid bio-oil is regarded as a promising candidate of petroleum fuels. However, bio-oil is a low-grade liquid fuel, and required to be upgraded before it can be directly utilized in existing thermal devices. Catalytic cracking is an effective way to upgrade bio-oil, which can be performed either on the liquid bio-oil or the pyrolysis vapors. Various catalysts have been prepared and used for catalytic cracking, and they exhibited different catalytic capabilities. This paper will review the recent progress of the catalytic cracking of liquid bio-oil or pyrolysis vapors.

The Effect of Doping Ce and Fe on the Mn/TiO2 Catalyst for Low Temperature NO Selective Catalytic Reduction with NH3

A series of manganese-cerium oxide support titanium oxide with different Fe/Ti, Ce/Ti ratio were investigated for selectivity catalytic reduction of NO low at temperature with NH3 as a reducing agent. The catalysts base Mn/TiO2 were prepared by sol-gel. The effect of amount of Ce and Fe oxide on the NO conversion of Mn/TiO22was studied. X-ray diffraction (XRD), temperature program desorption (TPD) were carried out. It was known that cerium oxides and iron oxide promoted preformance of Mn/TiO2 for low temperature. because Lewis is mainly take important role in the reaction for low temperature.

Erosion Mechanism of Platen Heating Surfaces in CFB

A two-dimensional numerical gas-solid flow models without chemical reactions is developed to simulate gas-solid flow in the fluidized bed boiler through MFIX software. Platen heating surfaces is considered in the upper of the furnace. Considering that velocity and concentration are the most factor effecting on erosion, there are three main area suffered serious erosion: (1) There is a maximum velocity at the position ( X = 57 cm, Y= 60 cm) on the right side of the wall, which will produce serious impact and erosion. (2) In the vicinity of position (X = 57 cm, Y= 140 cm) will suffer serious impact and tear. (3) As to the platen heating surfaces, the lower part which connect with flow is slightly wear and impacted. While the velocity on the right part is relatively large, especially in the corner of position (X = 24 cm, Y= 147 cm) reach a maximum.

Recent Progress in Biomass Tar Catalytic Cracking Method Research

A major problem in the current biomass gasification systems is the formation of tar. The condensed tar at low temperatures may cause blockage and pollution of downstream equipments, as well as environmental pollution. Therefore, the removal and conversion of tar are the key issues for biomass gasification. At present, the common methods of tar removal are mainly mechanism methods, thermal cracking and catalytic cracking. In this paper, the catalytic cracking method and its advantages and disadvantages are discussed.

Overview of Chemical Characterization of Biomass Fast Pyrolysis Oils

Fast pyrolysis of biomass to produce bio-oil is one of the most promising technologies to utilize lignocellulosic biomass. Liquid bio-oil covers many potential application fields, to be used a fuel or a source for chemical extraction and production. Hence, it is necessary to understand the chemical properties of bio-oil. This review concentrates on the elemental and chemical properties of bio-oil, and also discusses the analysis and separation methods.