Search results for "Pyrolysis"
showing 10 items of 170 documents
Fast pyrolysis of hot-water-extracted and delignified Norway spruce (Picea abies) sawdust by Py-GC/MS
2019
The thermochemical behavior of Norway spruce (Picea abies) sawdust as such and after various chemical treatments (hot-water extraction, delignification, and hot-water extraction followed by delignification) was investigated by analytical pyrolysis–gas chromatography–mass spectrometry. In each case, the yields of major GC-amenable condensable products were semi-quantitatively measured, and the individual compounds were classified into several compound groups. The formation of these groups from feedstock samples with varying mass portions of their structural constituents (carbohydrates and lignin) was determined at 500 °C and 700 °C with a residence time of 5 s and 20 s. The formation of pyro…
Effects of Briquetting and High Pyrolysis Temperature on Hydrolysis Lignin Char Properties and Reactivity in CO-CO2-N2 Conditions
2021
Carbonaceous reductants for pyrometallurgical applications are usually obtained from fossil-based sources. The most important properties of the reductants greatly depend on the application and the feeding of the reductant into the process. However, the mechanical strength, calorific value, fixed carbon content, and reactivity of the reductant are the properties that usually define the applicability of the reductant for different processes. The reactivity of the biochars is usually high in comparison to metallurgical coke, which may restrict the applicability of the biochar in reduction processes. One cause of the higher reactivity is the higher surface area of the biochars, which can be sup…
Influence of torrefaction pretreatment on the pyrolysis of Eucalyptus clone: A study on kinetics, reaction mechanism and heat flow
2016
Abstract The adverse nature of biomass requires specific pretreatment processes to better utilize it in bioenergy applications, and torrefaction is one of the most recognized thermal pretreatment methods. In this regard, we studied the effect of torrefaction pretreatment on kinetics, reaction mechanism and heat flow during the pyrolysis of biomass by making a comparative analysis between the pyrolysis of dried and torrefied Eucalyptus wood. Torrefied biomass was produced at three temperatures, namely 250, 275 and 300 °C. Pyrolysis was performed at 700 °C. The char yield during pyrolysis increased from 22.39 percent to 36.34 percent when the torrefaction temperature was increased from 250 to…
Analytical pyrolysis of wood and non-wood materials from integrated biorefinery concepts
2019
Wood and non-wood differ with respect to their anatomical, physical, and chemical properties, even among their species, resulting in different behaviors during thermal conversion. Hence, understanding the degradation of these feedstocks by pyrolysis is attractive to establish biorefinery possibilities for renewable resources. Additionally, biomass pretreatment technology plays an important role in many biorefinery processes. Therefore, an approach that integrates such pretreatment with pyrolysis offers an attractive, novel method for improving the end-product spectrum (e.g., enriched either with aliphatic or aromatic constituents). Furthermore, a rapid analytical method for biomass feedstoc…
Combustion behavior of black liquors : droplet swelling and influence of liquor composition
2017
The combustion of black liquor (BL) in a recovery boiler is a central process in a kraft pulp mill for recovering the cooking chemicals and for producing heat and power. This work explored the most important combustion behavior of BL, the swelling of in-flight droplets, from the viewpoint of liquor composition. It also studied the combustion behavior of BL droplets obtained from two biorefining subprocesses (carbonation and hot-water pretreatment, HWP) and sulfur-free pulping alternatives (soda-anthraquinone (AQ) and oxygen-alkali pulping). The formation of a plastic state essential for the swelling of BL droplet was found to result from the melting of an array of carbohydrate-derived aliph…
Block copolymers from ionic liquids for the preparation of thin carbonaceous shells
2017
This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.
Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar
2018
Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar poro…
Pyrolytic behavior of lignocellulosic-based polysaccharides
2018
The thermochemical behavior of cellulose, glucomannan, and xylan was investigated by pyrolysis–gas chromatographymass spectrometry (Py-GC/MS). In each case, major GC-amenable condensable products were classified into several compound groups, and the formation of these monomer-related fragments from the model substance samples was determined at 500, 600, and 700 C with a residence time of 5 s and 20 s. The results revealed that despite some general formation trends, no compound group was selectively formed at certain temperatures. Of the 11 product groups, the primary ones, including lactone, furan, and cyclopentenone derivatives, accounted for 72–85% (from cellulose), 86–90% (from glucomann…
Pyrolytic formation of polycyclic aromatic hydrocarbons from sesquiterpenes
2012
Author's version of an article in the journal: Food Chemistry. Also available from the publisher at: http://dx.doi.org/10.1016/j.foodchem.2012.06.033 The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500 °C, the products determined by GC–MS and then examined for similarities and differences using multivariate data analysis. Analysis showed that longifolene was most resistant and caryophyllene least resistant to pyrolysis with cedrene and valencene occupying intermediate positions. While the compounds were largely unchanged at 300 °C, polycyclic aromatic hydrocarbons (PAHs…
Understanding the White-Emitting CaMoO4 Co-Doped Eu3+, Tb3+, and Tm3+ Phosphor through Experiment and Computation
2019
In this article, the synthesis by means of the spray pyrolysis method, of the CaMoO4 and rare-earth cation (RE3+)-doped CaMoO4:xRE3+ (RE3+ = Eu3+, Tb3+, and Tm3+; and x = 1, 2, and 4% mol) compounds, is presented. The as-synthesized samples were characterized using X-ray diffraction, Rietveld refinement, field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) spectroscopy. To complement and rationalize the experimental results, first-principles calculations, at the density functional theory level, have been performed to analyze the band structure and density of states. In addition, a theoretical method based on the calculations of surface energie…