Search results for "kuivatislaus"
showing 8 items of 8 documents
Pyrolysis-gas chromatography : mass spectrometry analysis of di- and triterpenoids
2017
The objective of this work was to study a specific class of extractives existing in lignocellulosic biomass and more precisely in wood materials, and their thermochemical behavior during pyrolysis. The focus was centered on the class of terpenes and terpenoids; specifically two model compounds, abietic acid and betulinol, were chosen to represent the subclasses of di- and triterpenoids, respectively. The model compounds were investigated via pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and the main objective was to study their product profiles and characteristic fragmentations, as well as the influence of specific variables (pyrolysis temperature and time) on pyrolysis products…
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…
Märkälujaliimojen määritys pyrolyysi-kaasukromatografi-massaspektrometrillä
2017
Polymeerien, kuten märkälujaliimojen, analysoiminen on ollut nykyisillä menetelmillä erittäin työlästä tai hidasta. Pyrolyysi edustaa kuitenkin menetelmää, jolla esikäsittely ja aika saadaan minimiin. Menetelmässä näyte pilkotaan pienemmiksi yhdisteiksi, jolloin näyte saadaan helpommin analysoitavaan muotoon. Yleisimmin pyrolyysiä käytetään yhdessä kaasukromatografian kanssa. Työn kirjallisessa osassa perehdyttiin yleisimpien märkälujaliimojen valmistukseen, rakenteisiin ja ominaisuuksiin. Kirjallisuuskatsauksessa käytiin myös läpi pyrolyysin periaatteet, sovellukset sekä kartongin ja eräiden märkälujaliimojen pyrolyysituotteet. Lisäksi työssä perehdyttiin typpimäärityksiin. Työn kokeellise…
Fast pyrolysis of hot-water-extracted and soda-AQ-delignified okra (Abelmoschus esculentus) and miscanthus (miscanthus x giganteus) stalks by Py-GC/MS
2018
Abstract The thermochemical behavior of various samples of okra ( Abelmoschus esculentus ) and miscanthus ( Miscanthus x giganteus ) stalks (initial, hot-water-extracted, and those from sulfur-free delignification) were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In all cases, major GC-amenable condensable products were measured semi-quantitatively and classified into several product groups. The formation of these product groups from different feedstock samples with varying mass portions of their structural constituents (carbohydrates and lignin) was investigated at 500 °C and 700 °C with a residence time of 5 s and 20 s. The main product groups were aliphatic comp…
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…
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…
Kolmivaiheisen pyrolyysiprosessin mallintaminen
2015
Työssä rakennetun mallin avulla määritettiin kolmivaiheisen hitaan pyrolyysiprosessin massa- ja energiavirrat. Mallissa reaktoriin syötettiin 2 kg tuoretta mäntyä, josta kuivausvaiheen jälkeen saatiin tuotteena 1 kg kuivaa puuta. Lämpötilassa 260 °C suoritetun torrefioinnin kiintosaanto oli 0,84 kg torrefiointiöljyn 0,13 kg ja kaasujen 0,04 kg. Hapan torrefiointiöljy sekä torrefiointikaasut johdettiin ulos prosessista ja torrefioitu puu pyrolysoitiin 450 °C:ssa, jolloin muodostui biohiiltä 0,28 kg, pyrolyysiöljyä 0,35 kg ja pyrolyysikaasuja 0,37 kg kiloa torrefioitua puuta kohti. Kuivausvaihe kulutti energiaa 3260 kJ/kg-tuore puu ja torrefiointi 619 kJ/kg-kuiva puu. Pyrolyysivaihe sen sijaa…