Pyrolysis

About: Pyrolysis is a research topic. Over the lifetime, 34918 publications have been published within this topic receiving 833524 citations.

Acidity of biomass fast pyrolysis bio-oils

Abstract: The use of the total acid number (TAN) method for measuring the acidity of biomass fast pyrolysis bio-oil was evaluated. Suggestions for carrying out the analysis have been made. The TAN method by American Society for Testing and Materials (ASTM) D664 or D3339 can be used for measuring the acidity of fast pyrolysis bio-oils and their hydrotreating products. The main difference between the methods is that ASTM D664 is specified for higher TAN values than ASTM D3339. Special focus should be placed on the interpretation of the TAN curves because they differ significantly from those of mineral oils. The curve for bio-oils is so gentle that the automatic detection may not observe the end point properly, and derivatization should be used. The acidity of fast pyrolysis bio-oils is mainly derived (60−70%) from volatile acids. Other groups of compounds in fast pyrolysis bio-oils that influence acidity include phenolics, fatty and resin acids, and hydroxy acids.

Product Composition and Kinetics of Lignite Pyrolysis

Abstract: Previous research at M.I.T. on coal pyrolysis in inert gas and in hydrogen was based on the measurement of coal weight loss, referred to as volatiles yield. The work is now being extended to include volatiles composition measurements and elemental analysis of the char for the same ranges of experimental conditions covered in the previous study. To this end, the previous apparatus has been modified to permit the collection and analysis of volatiles. This paper presents the first set of composition data, for lignite pyrolysis, and some initial interpretations of pyrolysis behavior in the light of the products formed. The pyrolysis of pulverized Montana lignite by time-resolved measurement of the yields and compositions of products formed under controlled temperature-time histories was studied in a captive sample apparatus. The yields of water, carbon monoxide, carbon dioxide, hydrogen, and hydrocarbon gases and light liquids were determined by gas chromatography. The yields of all the volatile products increase monotonically with temperature and approach asymptotic values at the higher temperatures.

Attainment of the Theoretical Yield of Carbon from Biomass

Abstract: Previous work has shown that very high yields of charcoal are obtained when pyrolysis of the biomass feedstock is conducted at elevated pressure in a closed vessel, wherein the pyrolytic vapors are held captive and in contact with the solid products of pyrolysis In this paper, we show that, for some biomass species, the yield of carbon produced by this process effectively attains the theoretical value predicted to exist when thermochemical equilibrium is realized Various agricultural wastes (eg, kukui nut, macadamia nut, and pecan shells) and tropical species (eg, eucalyptus, leucaena, and bamboo) offer higher yields of carbon than the hardwoods traditionally employed by industry in the US and Europe Moreover, the yields of carbon from oat and rice hulls and from sunflower seed hulls are nearly as high as the yields of carbon from hardwoods There is a correlation between the yield of carbon and the acid-insoluble lignin content of the feed Charcoal briquettes made from agricultural wastes and lump charcoal from tropical species are promising sources of renewable carbon for use in the smelting of metal ores

Hydrogen from Biomass: Steam Reforming of Model Compounds of Fast-Pyrolysis Oil

Abstract: We investigated the production of hydrogen by the catalytic steam reforming of model compounds of biomass fast-pyrolysis oil (bio-oil). Acetic acid, m-cresol, dibenzyl ether, glucose, xylose, and sucrose were reformed using two commercial nickel-based catalysts for steam reforming naphtha. The experiments were conducted at a methane-equivalent gas hourly space velocity (GC1HSV) from 500 to 11790 h-1. Steam-to-carbon ratios (S/C) of 3 and 6 and catalyst temperatures from 550 to 810 °C were selected. Rapid coking of the catalyst was observed during acetic acid reforming at temperatures lower than 650 °C. Acetic acid, m-cresol, and dibenzyl ether were completely converted to hydrogen and carbon oxides above this temperature, and hydrogen yields ranged from 70 to 90% of the stoichiometric potential, depending on the feedstock and reforming conditions. Sugars were difficult to reform because they readily decomposed through pyrolysis in the freeboard of the reactor. This led to the formation of char and gases b...