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Theoretical studies pyrolysis

Despite the increasing munber of theoretical studies of individual steps, a full picture of the gas-phase chemistry has not yet been deduced. Both the physical transport effects as well as the gas-phase chemistry have to be taken into consideration. Even the most elaborate mechanisms [83-86] rely on the possibly erroneous experimental activation energies for GaMes pyrolysis in the gas phase. Neither GaN etching [96] at high temperatures nor pressure-dependent rates [95] have been included in the mechanisms. In addition, the cyclic oligomers [Mc2GaNH2]x with x = 2,3 are taken either as dead ends or as direct precursors to GaN via further methane elimination, whereas a rad-... [Pg.59]

ABSTRACT A novel reactor configuration has been developed in our laboratory which addresses the heat transfer limitations usually encountered in vacuum pyrolysis technology. In order to scale-up this reactor to an industrial scale, a systematic study on the heat transfer, the chemical reactions and the movement of the bed of particles inside the reactor has been carried out over the last ten years. Two different configurations of moving and stirred bed pilot units have been used to scale-up a continuous feed vacuum pyrolysis reactor, in accordance with the principle of similarity. A dynamic model for the reactor scale-up was developed, which includes heat transfer, chemical kinetics and particle flow mechanisms. Based on the results of the experimental and theoretical studies, an industrial vacuum pyrolysis reactor, 14.6 m long and 2.2 m in diameter, has been constructed and operated. The operation of the pyrolysis reactor has been successful, with the reactor capacity reaching the predicted feed rate of 3000 kg/h on a biomass feedstock anhydrous basis. [Pg.1296]

A theoretical study of the intermediates involved in the formation of phospha-propyne from pyrolysis of vinylphosphirane has led to a new route to phospha-alkynes. Thus, pyrolysis of trimethylsilyl(l-phosphiranyl)diazomethane has yielded MeaSiC = P, via an intermediate 1-phosphiranylmethylene . Regioselec-tivity in the [3 + 2] cycloaddition reaction between phosphaethyne and diazomethane has been studied by theoretical techniques , and further examples of reactions of this type described . Cycloaddition of phospha-alkynes with silylenes has also been reported. The primary phosphine 324 has been isolated from the addition of diethylphosphite to t-butylphosphaethyne. The chemistry of phospha-alkyne cyclotetramer systems has been reviewed and the first examples of platinum(II) complexes of such cage systems described. Aspects of the reactivity of coordinated phospha-alkynes have received further study, and a remarkable metal-mediated double reduction of t-butylphosphaethyne to the complexed fluorophosphine 325 described Phosphorus-carbon-aluminium cage structures have been isolated from the reactions of kinetically stable phospha-alkynes with trialkylaluminium compounds and new phosphaborane systems have been obtained from the reactions of phospha-alkynes with polyhedral boranes . Further studies of wo-phospha-alkyne coordination chemistry have appeared . The reactivity of the ion 326 has been explored. ... [Pg.42]

Yang J, Wang G et al (2013) Theoretical study on detonation performances and pyrolysis mechanism of pentaerythritol tetranitrate and its analogue compounds. Encarg Mater 21 (5) 570-577... [Pg.16]

Due to the existence of five-membered furan rings in low-rank coals [49], the pyrolysis mechanism of furan has become the subject of several experimental studies [50-52]. Recently, some detailed theoretical studies have been carried out to understand the formation processes of CO, C3H4 (propyne and aUene), ketene, acetylene, and so on. [Pg.244]

The effects of a-methylation on the gas-phase reaction kinetics and the mechanism of the pyrolysis of ethyl acetates have been theoretically studied at semi-empirical PM3 level. All the calculations showed that the thermal decomposition of alkyl acetates is a concerted asynchronous process via a six-membered cyclicTS, with the a-methyl substitution having a steric releasing effect in the TS. [Pg.362]

Biinzaii V, Korotcenkov G, Schwank J, Lantto V, Saukko S, Golovanov V (2002) Morphological rank of nano-scale tin dioxide films deposited by spray pyrolysis from SnC(,-5HjO water solution. Thin Solid Films 408(l-2) 51-58 Brynzari V, Korotchenkov G, Dmitriev S (2000) Theoretical study of semiconductor thin film gas sensitivity attempt to consistent approach. J Electron Technol 33 225-235... [Pg.295]

Golovanov V, MaM-Jaskari MA, Rantala TT, Korotcenkov G, Brinzari V, Comet A, Morante J (2005) Experimental and theoretical studies of the indium oxide-based gas sensors deposited by spray pyrolysis. Sens Actuators B 106 563-571... [Pg.107]

Huang J, Li X, Wu D, Tong H, Li W. Theoretical studies on pyrolysis mechanism of guaiacol as lignin model compound. J Renew Sustain Energy. 2013 5 043112. [Pg.183]

Two linear columns from Showa Denko, Shodex SB-806M and Shodex SB-806MHQ, and two linear columns from TosoHaas, TSK GM-PWxl and TSK GM-PW, were evaluated. Prior to the evaluation, the number of theoretical plates for Shodex SB-806MHQ, SB-806M, PWxl, and PW was determined to be 15,100, 15,700, 11,390, and 4710, respectively, as per manufacturer inspection. The lower plate count of the TSK PW column is due to the larger particle size of this column. Two mobile phases, water with 0.1 M LiNOi and 50 50 methanol/water (v/v) with 0.1 M LiNOi, were used for each of the four columns. These four columns were new and only PEO and PVP were analyzed with these columns in this study. Waters Ultrahydrogel columns have also been used in this laboratory. However, Ultrahydrogel columns are exactly the same as the TSK GM-PWxl columns based on the calibrations curves supplied by the manufacturers and by the pyrolysis GC data discussed later. [Pg.501]

D, W. Blair, CombustFlame 20 (1), 105—9 (1973) CA 78, 113515 (1973) A simple heat-transfer model is coupled with an Arrhenius-type pyrolysis law to study the effect of solid-state heat-transfer losses on burning rates of solid rocket-proplnt strands. Such heat-transfer losses materially affect the burning rates and also cause extinction phenomena similar to some that had been observed exptly. Strand diam and compn, adiabatic burning rate, and the heat-transfer film coeff at the strand surface are important variables. Results of theoretical analysis are applied to AP-based composite solid proplnts... [Pg.940]

The CVD of graphite is theoretically simple and is based on the thermal decomposition (pyrolysis) of a hydrocarbon gas. The actual mechanism of decomposition, however, is complex and still not completely understood. This may be due, in part, to the fact that most of the studies on the subject of hydrocarbon decomposition are focused on the improvement of fuel efficiency and the prevention of carbon formation (e.g., soot), rather than the deposition of a coating. [Pg.187]


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Pyrolysis studies

Theoretic Studies

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