Measured temperatures of burning pulverized-fuel particles, and the nature of the primary reaction product

AbstractKaolin wastes from the Capim and Jari regions (Brazil) were used to produce sodalite under the same conditions used in the Bayer process, in order to control its formation when necessary. Of the two kaolin source materials, the kaolinite from the Jari region was more reactive in the synthesis of sodalite, which is attributed to the low degree of structural order of this clay mineral which increased its reactivity. At a temperature of 150°C and with a Na/Al ratio of 2, although the kaolinite did not react completely, sodalitewas the primary reaction product. An increase in the temperature to 200°C provoked the complete reaction of the kaolinite only for the products in which carbonate and sulfate were used. With a Na/Al ratio >2 and for both of the temperatures, the kaolinite reacted completely to form sodalite.

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Reaction of trans-4-N-acetoxy-N-acetylaminostilbene with guanosine and deoxyguanosine in vitro: The primary reaction product at N2 of guanine yields different final adducts

Chemico-Biological Interactions ◽

10.1016/0009-2797(88)90090-7 ◽

1988 ◽

Vol 67 (1-2) ◽

pp. 105-116 ◽

Cited By ~ 8

Author(s):

R. Franz ◽

H.-G. Neumann

Keyword(s):

Primary Reaction ◽

Primary Reaction Product

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Validation of a thermal non-equilibrium Eulerian-Eulerian multiphase model of a 620 MWe pulverized fuel power boiler

MATEC Web of Conferences ◽

10.1051/matecconf/202134700004 ◽

2021 ◽

Vol 347 ◽

pp. 00004

Author(s):

Brad Rawlins ◽

Ryno Laubscher ◽

Pieter Rousseau

Keyword(s):

Heat Fluxes ◽

Multiphase Model ◽

Eulerian Model ◽

Combustion Dynamics ◽

Pulverized Fuel ◽

Fuel Particles ◽

Flexible Operation ◽

Power Boiler ◽

Modelling Approach ◽

Non Equilibrium

The use of a thermal non-equilibrium Eulerian-Eulerian model for the simulation of a 620 MWe power boiler is proposed for capturing the combustion and radiative heat transfer found in the pulverized fuel systems. The models eliminates the use of a Lagrangian reference frame in tracking solid fuel particles thereby reducing the computational expense and time. The model solves the scalar transport for the particle mass, energy and radiation interactions between the pseudo-particle and continuous phases. The goal is to apply the modelling approach to generate a simulation database for different load cases and firing conditions which in turn will be used to study flexible operation. The model is validated against both numerical and applicable site data measurements. It is shown that the model is able to adequately resolve the furnace and superheater wall heat fluxes. Additionally the resolution of the flow field, combustion dynamics and wall fluxes are demonstrated for both an 80% and 60% operational loads. Moreover, it is shown that the Eulerian-Eulerian model results in approximately a 30% computational resource reduction when compared to traditional modelling approaches.

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Experimental studies of ignition behaviour and combustion reactivity of pulverized fuel particles

Fuel ◽

10.1016/0016-2361(92)90049-t ◽

1992 ◽

Vol 71 (11) ◽

pp. 1239-1246 ◽

Cited By ~ 24

Author(s):

Dong-ke Zhang ◽

Terry F. Wall ◽

David J. Harris ◽

Ian W. Smith ◽

Jianyuan Chen ◽

...

Keyword(s):

Experimental Studies ◽

Pulverized Fuel ◽

Fuel Particles ◽

Combustion Reactivity

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Laser-induced ignition of pulverized fuel particles

Combustion and Flame ◽

10.1016/0010-2180(92)90115-6 ◽

1992 ◽

Vol 90 (2) ◽

pp. 134-142 ◽

Cited By ~ 33

Author(s):

Dong-Ke Zhang

Keyword(s):

Pulverized Fuel ◽

Fuel Particles ◽

Induced Ignition

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Effect of pH on the mechanism of OClO· oxidation of aromatic compounds

Canadian Journal of Chemistry ◽

10.1139/v02-089 ◽

2002 ◽

Vol 80 (7) ◽

pp. 761-766 ◽

Cited By ~ 5

Author(s):

Doug Svenson ◽

John F Kadla ◽

Hou-min Chang ◽

Hasan Jameel

Keyword(s):

Isotope Effect ◽

Radical Cation ◽

Chlorine Dioxide ◽

Kinetic Isotope Effect ◽

Degradation Products ◽

Primary Reaction ◽

Benzyl Alcohols ◽

Benzyl Radical ◽

Kinetic Isotope ◽

Primary Reaction Product

Contrary to previous reports, the reaction mechanism of chlorine dioxide (OClO·) with benzyl alcohols involves both radical cation and benzyl radical mechanisms dependent on pH. The primary reaction product between OClO· and 1-(3,4-dimethoxy-phenyl) ethanol at pH 8 is 3,4-dimethoxyacetophenone. At pH 4 no acetophenone was observed; the majority of the degradation products were chlorinated and aromatic ring-oxidized compounds. A primary kinetic isotope effect (kH/kD = 2.05) was observed in the reaction of OClO· with 1-(3,4-dimethoxy-phenyl)-(1-2H) ethanol at pH 8, but was absent at pH 4 (kH/kD [Formula: see text] 1). Similarly, the corresponding methyl ether (4-(1-methoxy)ethyl-1,2-dimethoxybenzene) was substantially less reactive at pH > 6. On the basis of these results, competing pH-dependent reaction mechanisms have been proposed, where at high pH OClO· reacts with benzyl alcohols via a OClO·benzyl alcohol complex.Key words: chlorine dioxide, mechanism, kinetic isotope effect, aromatic radical cation, benzyl radical.

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Kinetic Analysis of Organic Halides. IV. Analysis of Macromolecular Polyhalides

Rubber Chemistry and Technology ◽

10.5254/1.3543420 ◽

1952 ◽

Vol 25 (3) ◽

pp. 573-581 ◽

Cited By ~ 1

Author(s):

G. Salomon ◽

C. Koningsberger

Keyword(s):

Natural Rubber ◽

Kinetic Analysis ◽

Synthetic Polymers ◽

Infrared Analysis ◽

Reaction Products ◽

Primary Reaction ◽

Organic Halides ◽

Allylic Chloride ◽

Primary Reaction Product

Abstract Chlorination products derived from natural rubber and some synthetic polymers have been subjected to kinetic analysis with aniline at 100° C and piperidine at 20° C. The influence of the chlorinating agent on the structure of the reaction products has been elucidated. It is shown that allylic chloride groups, the rubber dichloride, (see PDF for diagram) and rubber polychlorides can be identified and separated kinetically. By a combination of kinetic and infrared analysis the structure (see PDF for diagram) can be proved as the primary reaction product of direct chlorination.

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Photochemical Breakdown of Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3546821 ◽

1946 ◽

Vol 19 (2) ◽

pp. 283-286

Author(s):

L. Bateman

Keyword(s):

Absorption Spectrum ◽

Wave Length ◽

Photochemical Activity ◽

The Other ◽

Cross Linking ◽

Ultraviolet Absorption Spectrum ◽

Hydroxyl Groups ◽

Primary Reaction ◽

Residual Oxygen ◽

Primary Reaction Product

Abstract A notable property of rubber and related olefins is their marked photochemical response to weakly absorbed light of wave-length greater than 3000 A. Although, as in photoinduced halogenation and oxidation, for example, photoactivation of the olefins cannot be generally inferred since the active absorbing entity is or may be the added reagent or a primary reaction product, the photogelling of rubber in a nonabsorbing solvent such as cyclohexane seems free from this ambiguity and points to direct photodecomposition of the rubber molecule. Some authors attribute the cross-linking of the gel state to C—C bonds between ethylenic centers and thereby explain the slightly reduced unsaturation of the gels and their resistance to rubber peptizing agents. Naunton, on the other hand directs attention to the remarkable gelling and reversion powers of minute traces of oxygen, and suggests that the few oxygenated centers which appear to remain even in highly purified rubber provide the sites for intermolecular condensation. This latter hypothesis undoubtedly expresses an important mode of cross-linking under certain conditions, but a possible inference that the oxygenated groups are regarded as specifically absorptive and as alone possessing photochemical activity is not in accord with existing evidence. The residual oxygen has been located analytically in hydroxyl groups and foreign chromophores are absent in the ultraviolet absorption spectrum of purified rubber. It is therefore difficult to see why the oxygenated fragments should be preferentially activated by irradiation rather than the much more numerous and more absorptive ethylenic units. However, a necessary prelude to further conjecture is fuller knowledge of the basic photochemistry of rigorously isolated rubber. In the work now described, scrupulous care has been taken to free the purified rubber from gaseous contaminants, and chemical changes have been followed directly and not deduced from vague gelation characteristics.

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Reaktionen von Titantetrachlorid mit Bistrimethylsilylsulfid. Die Kristallstrukturen von (NEt4)2[TiSCl4], (PPh4)2[TiSCl4]·2CH2Cl2, (PPh4)2[Ti3O(S2)3Cl6]CH3CN und Ti4O(S2)4Cl6 / Reactions of Titanium Tetrachloride with Bistrimethylsilyl Sulfide. Crystal Structures of (NEt4)2[TiSCl4], (PPh4)2[TiSCl4]·2CH2Cl2, (PPh4)2[Ti3O(S2)3Cl6]CH3CN and Ti4O(S2)4Cl6

Zeitschrift für Naturforschung B ◽

10.1515/znb-1988-1118 ◽

1988 ◽

Vol 43 (11) ◽

pp. 1501-1509 ◽

Cited By ~ 8

Author(s):

Volker Krug ◽

Gertraud Koellner ◽

Ulrich Müller

Keyword(s):

Titanium Tetrachloride ◽

Structure Type ◽

Disulfide Bridges ◽

Crystal Data ◽

Distorted Tetrahedron ◽

Primary Reaction ◽

X Ray ◽

Positional Disorder ◽

Structure Determinations ◽

Primary Reaction Product

The reaction of TiCl4 with (Me3Si)2S in dichloromethane yields black, insoluble, impure TiSCl2. In the presence of oxygen, additionally Ti3O(S2)3Cl4 and Ti4O(S2)4Cl6 are formed. By reactions of TiSCl2 with NEt4Cl and PPh4Cl in dichloromethane (NEt4)2[TiSCl2] and (PPh4)2[TiSCl4] ·2CH2Cl2 are formed, respectively. They were characterized by their IR spectra and by X-ray crystal structure determinations. They contain the square-pyramidal [TiSCl4]2- ion. which has a rather short Ti = S bond of 211.1(2) pm. Crystal data: (NEt4)2[TiSCl4]: tetragonal. P4/n, a = 923.9(3). c = 1406.7(2) pm. Z = 2. 966 unique observed reflexions. R = 0.053; positionally disordered ethyl groups. (PPh4)2[TiSCl4] · 2CH2Cl2: triclinic, P1, a = 1009.7(4), b = 1115.1(3). c = 1242.1(5) pm, α = 70.27(3), β = 79.06(3), γ = 81.37(3)°, Z = 1, 1504 reflexions, β-(AsPh4)2UCl6·2CH2Cl2 structure type, high R = 0.107 due to positional disorder of the anion. Addition of NEt4Cl or PPh4Cl in CH2Cl2 to the primary reaction product in presence of O2 yields (NEt4)2[Ti3O(S2)3Cl6] and (PPh4)2[Ti,O(S2)3Cl6] · CH2Cl2, respectively. Upon recrystallization of the latter from acetonitrile, (PPh4)2[Ti3O(S2)3Cl6] · CH3CN is obtained which forms triclinic crystals with a = 1138.8(3). b = 1268.8(4), c = 2166.4(6) pm, α = 101.26(3). β = 97.21(2). γ = 109.24(2)°, Z = 2, P1 (3053 reflexions, R = 0.070). The [Ti3O(S2)3Cl6]2- ion has a cluster-like structure with Ti atoms at the vertices of a triangle, with a μ3-O bridging atom and with tree bridging disulfide groups. Crystal data for Ti4O(S2)4Cl6: monoclinic, C2/c, a - 917.3(2), b - 1632.5(2), c = 1268.5(2) pm, β - 108.35(2)°, Z = 4. 1009 reflexions. R = 0.027. In the Ti4O(S2)4Cl6 molecule, four Ti atoms form a distorted tetrahedron around an μ4-O atom; two edges of the tetrahedron are spanned by chloro bridges, four edges by disulfide bridges.

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