Showing papers on "Pyrolysis published in 1987"

Chemical Kinetic Data Base for Combustion Chemistry. Part 2. Methanol

Abstract: This publication contains evaluated and estimated data on the kinetics of reactions involving methanol and hydroxymethyl radicals and various small inorganic and organic species which are of importance for the proper understanding of methanol combustion and pyrolysis. It is meant to be used in conjunction with the kinetic data given in an earlier publication pertaining to methane pyrolysis and combustion, but which also contains a large volume of data that are applicable to the methanol system. The temperature range covered is 300–2500 K and the density range 1×1016 to 1×1021 molecules cm−3.

Thermochemical Data on Gas Phase Compounds of Sulfur, Fluorine, Oxygen, and Hydrogen Related to Pyrolysis and Oxidation of Sulfur Hexafluoride

Abstract: Thermochemical data on selected gas phase compounds containing sulfur, fluorine, oxygen, and hydrogen are evaluated. These are of particular relevance to plasma chemistry and SF6 dielectric breakdown. Values of the enthalpies of formation and the entropy are provided at 298 K. Where no experimental data are available, methods for estimation have been developed for deriving the enthalpy of formation. Data are tabulated for 36 substances.

Investigation of organic sulfur-containing structures in coal by flash pyrolysis experiments

Abstract: Etude des composants contenant du soufre dans des charbons de differents degres de houillification, par pyrolyse eclair isotherme continue et spectrometrie GC/MS

Molecular characterization of the pyrolysis of biomass. 2. Applications

Abstract: On utilise la spectrometrie de masse a faisceau moleculaire en vue de caracteriser la nature chimique des huiles de pyrolyse de la biomasse et l'influence des parametres du materiau et des conditions operatoires sur le rendement et la nature de l'huile. On analyse egalement la chimie de la conversion de la phase gazeuse du point de vue des produits utiles et des effluents

Behavior of chromium, nickel, copper, zinc, cadmium, mercury, and lead during the pyrolysis of sewage sludge.

Abstract: Raw and digested sewage sludge samples were pyrolyzed in order to investigate the partitioning of selected heavy metals during anoxic thermal treatment. Cr, Ni, Cu, Zn, and Pb were retained quantitatively in the char at temperatures up to 750 /sup 0/C. Cd compounds were reduced to Cd/sup 0/, which was volatilized at T > 600 /sup 0/C. Hg was completely evaporated at the lowest investigated pyrolysis temperature of 350 /sup 0/C. The metals contained in the char are highly immobile due to the well-buffered neutral to alkaline properties of the char. Thus for sewage sludge, which contains metals with similar chemical and physical properties such as Cr, Ni, Cu, Zn, Cd, and Pb, pyrolysis at 500-600/sup 0/C might prove suitable since no metals are released to the atmosphere and a char is produced that is well suited for disposal in an inorganic sanitary landfill. 6 figures, 5 tables.

Method for preparing carbon fuel for smoking articles and product produced thereby

Abstract: The present invention is directed to methods for producing carbon containing fuel elements especially suited for use in cigarette--like smoking articles. One method of the present invention makes use of two separate pyrolysis steps to ensure that the carbon used to form the fuel elements for smoking articles is substantially free of materials which could adversely affect the aerosol delivered by such articles. Also disclosed is a method in which a fuel element formed from carbon and a binder is pyrolyzed after formation to convert the binder to carbon.

Method of using fast pyrolysis liquids as liquid smoke

Abstract: An aqueous wood smoke solution for flavoring foodstuffs is produced by heating in an oxygen starved atmosphere ground wood or cellulose to between 400° C. and 650° C. within 1.0 second; maintaining the said wood or cellulose and the primary pyrolysis vapors between 400° C. and 650° C. for between 0.03 and 2.0 seconds; reducing the temperature of the pyrolysis products to below 350° C. within 0.6 seconds; separating and collecting the water soluble liquid products; and diluting the said water soluble liquid products with water to achieve a partial phase separation and to reduce the benzo(a)pyrene concentration to less than 1.0 ppb.

Fluidized bed upgrading of wood pyrolysis liquids and related compounds

Abstract: The effective hydrogen index (EHI) is a calculated indicator of the ''net'' hydrogen/carbon ratio of a pure or mixed heteroatom-containing feed, after debiting the feed's hydrogen content for complete conversion of heteroatoms to NH/sub 3/, H/sub 2/S, and H/sub 2/O. Compounds with EHI's <--1 are difficult to upgrade to premium products over ZSM-5 catalyst due to rapid catalyst aging in continuous fixed bed processing. However, high conversions of such feeds (acetic acid, methyl acetate, and wood pyrolysis liquids) can be maintained in a fluidized bed system operating under methanol-to-gasoline conditions and employing frequent catalyst regeneration.

Method and apparatus for the pyrolysis of waste products

Abstract: A method and apparatus for use in processing waste materials of various kinds and for reclaiming useable by-product materials from the pyrolized waste materials. The waste materials to be pyrolized are efficiently dehydrated prior to their introduction into the pyrolysis retort using microwaves generated by a large microwave generator. After the waste material is dried, initial ignition is accomplished using a very high intensity laser beam. Laser ignition is continued until sufficient methane and other volatile gases are produced for burning in a burner unit to sustain the pyrolysis reaction.

Hydrogasification of biomass to produce high yields of methane

Abstract: A process for hydrogasification of biomass to produce high yields of methane utilizes a reactor capable of carrying out rapid pyrolysis. Biomass particles, hydrogen, particles of a suitable catalyst that has both cracking and hydrogenation activity, and heat are introduced into said reactor. Pyrolysis is carried out in a hydrogen-rich atmosphere under the following conditions: (a) a temperatue ranging from 500° C. to 550° C.; (b) a pressure equal to or greater than one atmosphere; (c) a gas residence time not exceeding two seconds; (d) a biomass particle residence time at least as long as the gas residence time; (e) a biomass particle size not exceeding 2 mm. The methane-rich product gas is then recovered. Conversion of carbon to methane of 69% has been attained using the process of the present invention.

Adaptation of the Unterzaucher procedure for determination of oxygen-18 in organic substances

Abstract: A method for the preparation of carbon dioxide from complex organic material for oxygen isotopic analysis is described. A commercial elemental analyzer has been modified so that oxygen contained in the organic material is quantitatively converted to carbon dioxide by the Schuetze-Unterzaucher technique, chromatographically purified, and transferred to a sample container for subsequent analysis by isotope ratio mass spectrometry. The organic sample is pyrolyzed, and the products of pyrolysis are equilibrated with elemental carbon at 1060 /sup 0/C to produce CO, and the CO is oxidized to CO/sub 2/ by I/sub 2/O/sub 5/. The details of these processes are considered, and a quantitative model is developed to allow correction for contamination of the carbon dioxide oxygen pool by an oxygen blank, oxygen from previous samples (memory), an oxygen from iodine pentoxide. Procedures for determination of the parameters used in the mathematical correction and routine application of the model to isotopic analysis are outlined. At natural abundance, the standard deviation for determination of the fractional abundance of oxygen-18 in a sample of organic material is 2 x 10/sup -7/ (equivalent to 0.1%). The detection limit for /sup 18/O as a tracer in biological materials is better than 1 atom excess/10/sup 6/more » atoms total O. Analyses of independently established standards show that results obtained by the mathematical correction procedure are accurate and allow determination of abundances of /sup 18/O in the sucrose standards prepared by Hardcastle and Friedman.« less

Alkyl- and arylsilsesquiazanes: effect of the R group on polymer degradation and ceramic char composition

Abstract: A series of alkyl- and arylsilsesquiazanes [RSi(NH)3/2] was prepared by the ammonolysis of the corresponding RSiCl3. Each polymer was pyrolysed to 1200° C in an inert atmosphere to give amorphous Si-C-N ceramic chars. The major volatile products in the pyrolysis effluent were identified and quantified by a combination of TGA-GCMS, TGA-GCFTIR and pyrolysis-capillary GC techniques. Mechanistic aspects correlating the alkyl/aryl group on the polymer structure, decomposition and ceramic char composition were studied. Oxidative stability of the ceramic chars fits percolation theory. The oxygen contents of ceramic chars containing ⩽ 25 wt% carbon increased 1 to 2% after 12 h at 1200° C. At higher levels of carbon the chars were completely oxidized to SiO2.