Showing papers on "Pyrolysis published in 1983"
TL;DR: In this paper, a demineralized lignite has been used in a fundamental study of the role of carbon active sites in coal char gasification, where the chars were prepared in N 2 under a wide variety of conditions of heating rate (10 K min −1 to 10 4 K s −1 ), temperature (975 − 1475 K) and residence time (0.3 s-1 h).
452 citations
TL;DR: In this paper, it was shown that although the modified van Krevelen diagram may be useful for tracing evolutionary pathways as organic matter matures, it can be very misleading when used to assess kerogen type.
385 citations
TL;DR: The relationship between the structure and the pyrolysis process of polycarbosilane fibres is discussed in this article, where five structural elements and the rate of oxidation of the methyl group are represented.
Abstract: Polycarbosilanes which were synthesized by three methods were melt-spun and cured by heating at low temperatures in air The curing mechanism and the structure of these cured fibres were studied and the relationship between the structure and the pyrolysis process is discussed The structure of the cured fibre is represented by means of five structural elements and the rate of oxidation of the methyl group The pyrolysis process of the cured fibre is discussed in five stages, and the effect of oxygen introduced into polycarbosilane fibre by curing on the pyrolysis process is clarified The structure of the fibre obtained during the pyrolysis process strongly depends on the molecular weight of polycarbosilane
336 citations
TL;DR: A molecular sieve carbon membrane (MSCM) that contains no pores greater than those of molecular dimensions was produced by pyrolysis of organic compounds as discussed by the authors, which shows gas permeabilities and selectivities that are considerably greater than any of the presently known polymer membranes.
Abstract: A molecular sieve carbon membrane (MSCM) that contains no pores greater than those of molecular dimensions was produced by pyrolysis of organic compounds. The MSCM, an outcome of recent studies on molecular sieve carbon adsorbents. shows gas permeabilities and selectivities that are considerably greater than any of the presently known polymer membranes. The permeates examined were He, CO2, O2, N2, and SF6. The pore dimensions of the same starting carbon membrane may be adjusted by simple thermochemical treatments to achieve optimal separation power for any gas mixture composition.
242 citations
01 Jan 1983
TL;DR: A normative review of the literature describing the products, mechanisms and rates of carbohydrate pyrolysis is presented in this article, where the role of a complex sequence of competing solid and vapor phase pathways is elucidated.
Abstract: A normative review of the literature describing the products, mechanisms and rates of carbohydrate pyrolysis is presented. The role of a complex sequence of competing solid and vapor phase pyrolysis pathways is elucidated.
227 citations
Book•
01 Jan 1983
TL;DR: In this paper, the authors study pyrolysis from theory and industrial practice from two perspectives: theory and practice, and provide a detailed discussion of the theoretical and industrial aspects of the process.
Abstract: This book is useful for the study of pyrolysis from two perspectives: theory and industrial practice. Topics included are thermal decompositions and reactions of methane pyrolysis of ethane and propane, pyrolysis of n-butane, thermal reaction of olefins and diolefins, pyrolysis of heavy hydrocarbons, formation of aromatics, hydrogenolysis of toluene, mathematical modeling of hydrocarbon pyrolysis reactions, nonpetroleum feedstocks, formation and gasification of coke, surface reactions in pyrolysis units, pyrolysis furnace design, laboratory reactors for pyrolysis, and economic considerations in the design and operation of conventional pyrolysis furnaces.
225 citations
TL;DR: In this article, the effects of pressure and purge gas flow rate (gas phase residence time) on the heat demands of cellulose pyrolysis were investigated using a Setaram DSC in conjunction with stainless steel pressure vessels.
219 citations
TL;DR: In this paper, the nature of the organic and mineral reactions during the pyrolysis of Saline-zone Colorado oil shale containing large amounts of nahcolite and dawsonite has been determined.
206 citations
TL;DR: In this article, pyrolysis products of babassu (Orbignya martiana), piqui (Caryocar coriaceum), and palm oils (Elaeis guineensis) were analyzed by GC/MS using library search programs.
Abstract: Pyrolysis products of babassu (Orbignya martiana), piqui (Caryocar coriaceum), and palm oils (Elaeis guineensis) were analyzed by GC/MS using library search programs. The chief products of pyrolysis were straight-chain alkanes and 1-alkenes. Small amounts of cyclic hydrocarbons were detected in triglycerides constituted by oleic acid as the major moiety. Pyrolysis of oleic acid was also studied. A pathway for the cracking reactions involved with the decomposition of the saturated fatty acids is
190 citations
TL;DR: In this paper, the dependence of gas yields on temperature and residence time was explained by a global mechanism composed of two competing reactions: the first creates permanent gases by cracking the volatile matter, whereas the second creates refractory condensable materials.
Abstract: Yields of permanent gases evolved by the gas-phase pyrolysis of cellulose- and lignin-derived voltatile matter cannot be correlated with a commonly used kinetic severity function. Instead, engineers explained the dependence of gas yields on temperature and residence time by a global mechanism composed of two competing reactions. The first creates permanent gases by cracking the volatile matter, whereas the second creates refractory condensable materials. For cellulose, the cracking reaction has an apparent activation energy of 49 kcal/g-mol, and the competing reaction 15 kcal/g-mol. The gas-phase cracking of cellulosic volatile matter involves competition between the dehydration (resulting in methane and ethylene formation) and decarboxylation reactions; the fraction of carbon atoms dedicated to carbon monoxide formation by the cracking reaction is not influenced by temperature. For lignin, competition exists between ethylene and carbon dioxide formation; the fraction of carbon atoms dedicated to carbon monoxide and methane formation is not influenced by temperature.
168 citations
TL;DR: In this article, the authors studied glycerol pyrolysis in a luminar flow reactor in the 650 °C region and found that the initial products of decomposition were carbon monoxide, acetaldehyde, acrolein, hydrogen, ethylene, methane, carbon dioxide, propylene and 1,.3-butadiene.
TL;DR: In this paper, carbon fibers of uniform diameter have been grown by pyrolysis of natural gas in type 304 stainless steel (18% Cr, 8% Ni) tubes at temperatures between 950 and 1075 °C.
Abstract: Carbon fibers of uniform diameter have been grown by pyrolysis of natural gas in type 304 stainless steel (18% Cr, 8% Ni) tubes at temperatures between 950 and 1075 °C. The method utilizes the circulation of wet hydrogen outside the growth tube in order to promote effective nucleation. Fibers 12 cm long having average moduli of 1.8×1011 Pa have been grown.
TL;DR: In this paper, the pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was used to determine the ratios of amylose compounds, acids, furans, pyranones anhydrosugars and aromatic substances.
TL;DR: A pyrolysis-gas chromatography system has been developed for the rapid evaluation of potential source rocks as mentioned in this paper, where the determination of hydrocarbon production type and the identification of contamination (by migrated hydrocarbons or drilling additives) are accomplished by gas chromatographic (GC) analysis of the thermal extracts of the rock samples or isolated kerogens.
Abstract: A pyrolysis-gas chromatography system has been developed for the rapid evaluation of potential source rocks. For the determination of organic richness and maturation, this system uses the pyrolysis methods previously described. However, the determination of hydrocarbon production type and the identification of contamination (by migrated hydrocarbons or drilling additives) are accomplished by gas chromatographic (GC) analysis of the thermal extracts and pyrolysis products of rock samples or isolated kerogens. The production type is recognized either qualitatively by GC fingerprint traces or quantitatively by hydrocarbon composition (C1 to C6, C6 to C11, C11+) from the kerogen (Peak II) pyrolysate. Oil-prone erogens are recognized by GC traces with a full spectrum of C1 to C28 hydrocarbons, or by high concentrations of C11+ compounds. In contrast, gas-prone kerogens are characterized by the predominance of light hydrocarbons from C1 to C4 and higher contributions of aromatic compounds. Mixed-type production is intermediate in character between the two. Contaminants are identified from the GC analysis of the thermally extractable material in Peak I. Possible mineral-organic matter reactions during sample heating make interpreting data from whole-rock samples more difficult.
TL;DR: In this paper, the pyrolysis of cellulose in vacuum from 22 to 765°C was followed by IR photothermal beam deflection spectroscopy, where the main decomposition occurred near 300°C, some decomposition occurs as low as 190°C with the formation or highly absorbing aromatic systems.
TL;DR: In this article, a demineralized North Dakota lignite was loaded with 2.9 wt% Ca by ion exchange and X-ray diffraction analysis was carried out to obtain information on the state and dispersion of the Ca species on the various chars.
TL;DR: In this article, thermal and wet chemical methods of separating organic from elemental carbon in particulate samples were examined and it was concluded that none of them represents an ideal separation procedure and that only a method-dependent operational definition of organic and elemental carbon is possible at this time.
Journal Article•
TL;DR: In this article, a three phase research program, using a tubular, laminar flow, micro reactor system, was undertaken to study the effects of pressure on biomass pyrolysis.
01 Jan 1983
TL;DR: In this article, the authors investigated the effect of pyrolysis conditions on biological markers and other diagnostic hydrocarbons, and showed that the effect on the evolution of oil is not additive.
Abstract: Oil yields, compositions and rates of evolution are reported for heating rates from 1 to 100/sup 0/C/h and pressures of 1.5 and 27 atm. Pyrolysis occurred in an autogenous atmosphere and volatile products were allowed to escape the pyrolysis region continuously. Higher pressures and lower heating rates during pyrolysis cause a decrease in oil yield, although the effects are not additive. The lowest oil yield was approximately 72 wt% or 79 vol% of Fischer assay. Lower oil yield is generally accompanied by lower boiling point distribution, nitrogen content and density and higher H/C ratios. Oils produced at high pressure and slow heating rates are a clear amber color instead of the usual opaque brown. The effect of pyrolysis conditions on biological markers and other diagnostic hydrocarbons is also discussed. Existing kinetic expressions for oil evolution slightly overestimate the shift in the oil evolution rate vs. temperature with a decrease in heating rate. Finally, the rate of oil evolution is retarded by pressure, a factor not taken into account by current kinetic expressions.
TL;DR: In an attempt to evaulate the hypothesis that petroleum formation can be simulated using high temperatures, Green River Shale from Colorado, U.S.A., was subjected to closed-system pyrolysis for 16 hr at temperatures ranging from 300 to 500°C.
TL;DR: In this article, the fine structure associated with phenols and ethers in coal pyrolysis liquids has been characterized and the contributions to the liquid pyrolysates of the phenolic functional groups already existing in coal have been separated from the contributions of these same same groups generated by ether cleavage during the pyroglysis.
01 Jan 1983
TL;DR: A series of experiments was carried out to observe the generation of the different classes of oil constituents Aliquots of two kerogens from the Green River Shales and the Lower Toarcian shales of the Paris Basin were heated at a constant heating rate of 4/sup 0/C/min to different final temperatures ranging from 375/sup 1/ to 550/sup 2/C The total amount and composition of the hydrocarbons generated is given.
Abstract: A series of experiments was carried out to observe the generation of the different classes of oil constituents Aliquots of two kerogens from the Green River Shales and the Lower Toarcian shales of the Paris Basin were heated at a constant heating rate of 4/sup 0/C/min to different final temperatures ranging from 375/sup 0/ to 550/sup 0/C The total amount and composition of the hydrocarbons generated is given A direct pyrolysis-gas chromatography of the kerogens was also performed Composition of the solid organic residue of pyrolysis was analyzed in order to follow the progressive change from the immature kerogen to the final char The two major causes for the differences observed between shale oil and crude oil were found to be due to the generation by pyrolysis of compounds unusual in natural bitumens and crude oils, such as unsaturated hydrocarbons (olefins); and due to the migrated character of pooled oil which results in a preferential migration of hydrocarbons, especially saturates, and a retention of most of the N, S, O/sup -/ compounds in the source rock (JMT)
TL;DR: In this article, a pyrolysis of anisoles was carried out using small batch autoclaves and it was shown that this rearrangement proceeds via a three-centered intermediate to para-fluorobenzaldehyde.
TL;DR: Very promising results have been obtained in pyrolysis experiments carried out in a sieve-tray reactor, of their design, in the temperature range 400-700°C, employing a suitable gas stream in order to rapidly remove the pyrolyssis products from the reactor and at the same time to activate the char.
TL;DR: In this article, the role of the metallic central atom is explained in terms of its catalytic influence on the pyrolysis of an active carbon-based catalytic catalyst.
TL;DR: In this article, electron spin resonance studies of the early stages of carbonization of a high-volatile A bituminous coal have been used to detect and quantify transient free radicals present in the coal pyrolysate.
TL;DR: In this article, the authors propose a decomposition of CH 2 CHSiH 3, C 2 H 5 SiH 3, C 3 H 7 SiH 7, (CH 3 ) 2 SiH 2, ( CH 3 ) 3 SiH et.