Molecular mechanisms for the gas-phase conversion of intermediates during cellulose gasification under nitrogen and oxygen/nitrogen

Asuka Fukutome; Haruo Kawamoto; Shiro Saka

doi:10.2298/ciceq160325018f

Molecular mechanisms for the gas-phase conversion of intermediates during cellulose gasification under nitrogen and oxygen/nitrogen

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq160325018f ◽

2016 ◽

Vol 22 (4) ◽

pp. 343-353 ◽

Cited By ~ 6

Author(s):

Asuka Fukutome ◽

Haruo Kawamoto ◽

Shiro Saka

Keyword(s):

Gas Phase ◽

Residence Time ◽

Molecular Mechanisms ◽

High Efficiency ◽

Experimental Setup ◽

Phase Conversion ◽

Gas Phase Reactions ◽

Secondary Reaction Zone ◽

Hydrocarbon Gas ◽

Molten Phase

Gas-phase conversions of volatile intermediates from cellulose (AvicelPH-101) were studied using a two-stage experimental setup and compared with those of levoglucosan (1,6-anhydro-b-D-glucopyranose). Under N2or 7% O2/N2flow, vapors produced from the pyrolysis zone (500?C) degraded in the secondary reaction zone at 400,500, 600 or 900?C (residence time:0.8-1.4 s). The 69.3% (C-based) of levoglucosan was obtained at 400?C under N2flow along with 1,6-anhydro-b-D-glucofuranose (8.3 %, C-based), indicating that these anhydrosugars are the major volatile intermediates from cellulose pyrolysis. Levoglucosan and other volatiles started to fragment at 600?C, and cellulose was completely gasified at 900?C. Most gas/tar formations are explained by gas-phase reactions of levoglucosan reported previously, except for some minor reactions originating from the molten-phase pyrolysis, which produced benzene, furans and 1,6-anhydro-b-D-glucofuranose. Synergetic effects of O2and volatiles accelerated fragmentation and cellulose gasification was completed at 600?C, which reduced benzene and hydrocarbon gas productions. The molecular mechanisms including the action of O2as a biradical are discussed. These lines of information provide insights into the development of tar-free clean gasification that maintains high efficiency.

Influence of Particle Size, Reactor Temperature and Gas Phase Reactions on Fast Pyrolysis of Beech Wood

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1922 ◽

2010 ◽

Vol 8 (1) ◽

Cited By ~ 1

Author(s):

Li Chen ◽

Capucine Dupont ◽

Sylvain Salvador ◽

Guillaume Boissonnet ◽

Daniel Schweich

Keyword(s):

Particle Size ◽

Gas Phase ◽

Residence Time ◽

Beech Wood ◽

Tubular Reactor ◽

Gaseous Product ◽

Drop Tube ◽

Gas Phase Reactions ◽

Molar Ratios ◽

Reactor Temperature

In the present work, a drop tube reactor (DTR) and a horizontal tubular reactor (HTR) were used to study the pyrolysis behaviour of beech wood particles of different sizes under the conditions encountered in industrial fluidized bed gasifiers, namely high external heat flux (105 106 W.m-2) and high temperature (800 1000°C). The influence of the reactor temperature (800 and 950°C), of particle size (from 350 µm to 6 mm), and of gas residence time (from 1 to 10 s) were examined. Under the explored conditions, when pyrolysis is finished, more than 80 wt.% of virgin wood is converted into gas and less than 13 wt.% remains in solid. In the gas phase, CO is the main gaseous product (50 wt.% of virgin wood), followed by H2 (molar ratios of H2/CO are between 0.35 to 0.55), H2O, CO2 and CH4. Species C2H2, C2H4, C2H6 and C6H6 are present in much lower amounts. The increase of temperature increases the rate of solid devolatilization and favours the cracking reactions of hydrocarbons. The increase of particle size increases the required time for completing pyrolysis. Meanwhile, the results obtained at 950°C show that the final products distribution at the end of pyrolysis is almost the same for the particles between 350 and 800 µm. The increase of the particle size from 800 µm to 6 mm seems to have some influence on the final products distribution. The gas phase reactions mainly change the yields of light hydrocarbons and H2: the increase of gas residence time favours the cracking reactions of hydrocarbons and thus leads to a higher H2 yield.

Gas-Phase Reactions

10.1007/978-3-642-67608-6 ◽

1981 ◽

Cited By ~ 41

Author(s):

Victor N. Kondratiev ◽

Evgeniĭ E. Nikitin

Keyword(s):

Gas Phase ◽

Gas Phase Reactions

Kinetic Study of Gas-Phase Reactions of Pyruvic Acid with HO2

The Journal of Physical Chemistry A ◽

10.1021/acs.jpca.0c10475 ◽

2021 ◽

Author(s):

Jonathan R. Church ◽

Veronica Vaida ◽

Rex T. Skodje

Keyword(s):

Kinetic Study ◽

Gas Phase ◽

Pyruvic Acid ◽

Gas Phase Reactions

Ce and Ca/Nb doped Pd-mesocellular foam catalysts for gas-phase conversion of acetone to methyl isobutyl ketone

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2021.111169 ◽

2021 ◽

pp. 111169

Author(s):

Kalina Grzelak ◽

Rouzana Pulikkal Thumbayil ◽

Søren Kegnæs ◽

Maciej Trejda ◽

Anders Riisager

Keyword(s):

Gas Phase ◽

Methyl Isobutyl Ketone ◽

Phase Conversion ◽

Methyl Isobutyl ◽

Isobutyl Ketone

Influence of Gas Mixing and Heating on Gas-Phase Reactions in GaN MOCVD Growth

ECS Journal of Solid State Science and Technology ◽

10.1149/2.031201jss ◽

2012 ◽

Vol 1 (1) ◽

pp. P46-P53 ◽

Cited By ~ 7

Author(s):

Ran Zuo ◽

Haiqun Yu ◽

Nan Xu ◽

Xiaokun He

Keyword(s):

Gas Phase ◽

Gas Mixing ◽

Gas Phase Reactions ◽

Mocvd Growth

Gas Phase Reactions Activated by Nuclear Processes

Journal of the American Chemical Society ◽

10.1021/ja01574a009 ◽

1957 ◽

Vol 79 (17) ◽

pp. 4609-4616 ◽

Cited By ~ 25

Author(s):

Adon A. Gordus ◽

John E. Willard

Keyword(s):

Gas Phase ◽

Gas Phase Reactions ◽

Nuclear Processes

Gas-phase reactions of alkylperoxy and alkoxy radicals part I. The photoinitiated oxidation of 2,3-dimethylbutane

Combustion and Flame ◽

10.1016/0010-2180(77)90103-1 ◽

1977 ◽

Vol 29 ◽

pp. 133-144 ◽

Cited By ~ 10

Author(s):

W.G. Alcock ◽

B. Mile

Keyword(s):

Gas Phase ◽

Gas Phase Reactions ◽

Alkoxy Radicals

Nanocomposite ceramic powder production by laser-induced gas-phase reactions

Materials Science and Engineering A ◽

10.1016/0921-5093(93)90724-s ◽

1993 ◽

Vol 168 (2) ◽

pp. 177-181 ◽

Cited By ~ 8

Author(s):

E Borsella ◽

S Botti ◽

R Alexandrescu ◽

I Morjan ◽

T Dikonimos-Makris ◽

...

Keyword(s):

Gas Phase ◽

Ceramic Powder ◽

Gas Phase Reactions ◽

Powder Production

Methylene. III. Gas phase reactions with 1-chloropropane

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1969.0146 ◽

1969 ◽

Vol 312 (1509) ◽

pp. 141-161 ◽

Cited By ~ 2

Keyword(s):

Gas Phase ◽

Rate Constants ◽

Hydrogen Abstraction ◽

The Other ◽

Gas Phase Reactions ◽

Other Hand ◽

Chlorine Substituent ◽

High Degree ◽

Singlet Methylene

The work described in this and the following paper is a continuation of that in parts I and II, devoted to elucidation of the mechanism of the reactions of methylene with chloroalkanes, with particular reference to the reactivities of singlet and triplet methylene in abstraction and insertion processes. The products of the reaction between methylene, prepared by the photolysis of ketene, and 1-chloropropane have been identified and estimated and their dependence on reactant pressures, photolysing wavelength and presence of foreign gases (oxygen and carbon monoxide) has been investigated. Both insertion and abstraction mechanisms contribute significantly to the over-all reaction, insertion being relatively much more important than with chloroethane. This type of process appears to be confined to singlet methylene. If, as seems likely, there is no insertion into C—Cl bonds under our conditions (see part IV), insertion into C2—H and C3—H bonds occurs in statistical ratio, approximately. On the other hand, the chlorine substituent reduces the probability of insertion into C—H bonds in its vicinity. As in the chloroethane system, both species of methylene show a high degree of selectivity in their abstraction reactions. We find that k S Cl / k S H >7.7, k T Cl / k T H < 0.14, where the k ’s are rate constants for abstraction, and the super- and subscripts indicate the species of methylene and the type of atom abstracted, respectively. Triplet methylene is discriminating in hydrogen abstraction from 1-C 3 H 7 Cl, the overall rates for atoms attached to C1, C2, C3 being in the ratios 2.63:1:0.

Kinetic Analysis of C4 Alkane and Alkene Pyrolysis: Implications for SOFC Operation

Journal of Fuel Cell Science and Technology ◽

10.1115/1.4000677 ◽

2010 ◽

Vol 7 (4) ◽

Cited By ~ 6

Author(s):

Ahmed Al Shoaibi ◽

Anthony M. Dean

Keyword(s):

Gas Phase ◽

Solid Oxide ◽

Oxide Fuel ◽

Pyrolysis Kinetics ◽

Fuel Conversion ◽

Substantial Impact ◽

Gas Phase Chemistry ◽

Gas Phase Kinetics ◽

Hydrocarbon Gas ◽

Phase Chemistry

Pyrolysis experiments of isobutane, isobutylene, and 1-butene were performed over a temperature range of 550–750°C and a pressure of ∼0.8 atm. The residence time was ∼5 s. The fuel conversion and product selectivity were analyzed at these temperatures. The pyrolysis experiments were performed to simulate the gas-phase chemistry that occurs in the anode channel of a solid-oxide fuel cell (SOFC). The experimental results confirm that molecular structure has a substantial impact on pyrolysis kinetics. The experimental data show considerable amounts of C5 and higher species (∼2.8 mole % with isobutane at 750°C, ∼7.5 mole % with isobutylene at 737.5°C, and ∼7.4 mole % with 1-butene at 700°C). The C5+ species are likely deposit precursors. The results confirm that hydrocarbon gas-phase kinetics have substantial impact on a SOFC operation.