An 11 Blockheizkraftwerken (BHKW) ohne Oxidationskatalysator und an 10 BHKW mit Oxidationskatalysator in Sachsen und Thüringen wurden die Einflussfaktoren auf die Formaldehydemissionen untersucht. Geprüft wurden insbesondere die Motorbetriebsparameter wie z.B. Zylindertemperaturen, Verbrennungsluftverhältnis, die Biogaszusammensetzung und die Biogasfeuchte. Im Ergebnis konnte kein bzw. nur ein geringer Einfluss der untersuchten Parameter auf die Formaldehydbildung festgestellt werden. Ebenfalls ließ sich bei den meisten der untersuchten Anlagen kein Einfluss von Wartungstätigkeiten sowie Ersatzteil- und Betriebsstoffwechseln auf die Formaldehydemissionen feststellen. Sollte der Gesetzgeber künftig einen niedrigeren Formaldehydgrenzwert vorschreiben, werden zusätzliche Technologien zur Biogasaufbereitung z.B. mit Aktivkohlefilter und zur Abgasnachbehandlung z.B. mit Oxidationskatalysator oder Thermoreaktor notwendig. Diese müssen aber noch hinsichtlich ihrer Standzeiten untersucht und optimiert werden.

An 11 Blockheizkraftwerken (BHKW) ohne Oxidationskatalysator und an 10 BHKW mit Oxidationskatalysator in Sachsen und Thüringen wurden die Einflussfaktoren auf die Formaldehydemissionen untersucht. Geprüft wurden insbesondere die Motorbetriebsparameter wie z.B. Zylindertemperaturen, Verbrennungsluftverhältnis, die Biogaszusammensetzung und die Biogasfeuchte. Im Ergebnis konnte kein bzw. nur ein geringer Einfluss der untersuchten Parameter auf die Formaldehydbildung festgestellt werden. Ebenfalls ließ sich bei den meisten der untersuchten Anlagen kein Einfluss von Wartungstätigkeiten sowie Ersatzteil- und Betriebsstoffwechseln auf die Formaldehydemissionen feststellen. Sollte der Gesetzgeber künftig einen niedrigeren Formaldehydgrenzwert vorschreiben, werden zusätzliche Technologien zur Biogasaufbereitung z.B. mit Aktivkohlefilter und zur Abgasnachbehandlung z.B. mit Oxidationskatalysator oder Thermoreaktor notwendig. Diese müssen aber noch hinsichtlich ihrer Standzeiten untersucht und optimiert werden.

New vigorous regulations have been established for decreasing the allowable formaldehyde emissions from nonstructural wood based composites. Two main sources of formaldehyde emission in non-structural wood based composites are adhesive and wood. Adhesives are quite well known and great efforts have been conducted to decrease their formaldehyde content; however formaldehyde emission from wood has received little attention and it is not completely understood. Wood-borne formaldehyde emission exists in a complex equilibrium in wood matrix. The reaction between formaldehyde and wood hydroxyl groups/water can hinder the complete formaldehyde extraction. In order to have a complete formaldehyde extraction, a stronger nucleophile than hydroxyl and water groups is needed. In this study cross-linked poly (allylamine) (PAA) beads were synthesized and used as a strong nucleophile to extract all the biogenic and synthetic free-formaldehyde within the woody matrix of never-heated and heat-treated Virginia pines; the results were compared to simple water extraction. A new formaldehyde capturing device was also developed using a serum bottle. Results showed that there was no advantage of using PAA beads over simple water extraction for extracting woody matrix free-formaldehyde. This means that simple water extraction can extract all the free-formaldehyde from the woody matrix. It was also found that thermal treatment resulted in generating more wood-borne formaldehyde. The other important finding was the new developed formaldehyde capturing device. The device was very promising for detecting wood-borne formaldehyde from very small pieces of wood (5-70 mg) and can be very useful in future studies. / Master of Science

Les marcs de raisin issus de la viniculture constituent un gisement de ressource naturelle abondant, sous valorisé et riche en polyphénols. Une méthode d?extraction de ces tannins condensés a été développée et optimisée en vue d'une application en adhésif pour les produits dérivés du bois. Les tannins ont été caractérisés par Résonance Magnétique Nucléaire, spectroscopie Infra Rouge (FTIR), spectrométrie de masse (MALDI TOF) et Analyse Thermomécanique (TMA). Des panneaux de particules ont été fabriqués à l'aide des colles élaborées en laboratoire et testés suivant les normes françaises en vigueur, plusieurs dépassent largement les valeurs seuils / The extraction of condensed tannins from grape pomace was examined using water medium in the presence of different bases as catalyst (NaOH, Na2CO3, NaHCO3 and Na2SO3). Two different extraction processes and the influence of 4 parameters (i.e., temperature, reaction time, chemical reagents and concentration of the chemical reagents) on the tannin extracts yields and properties were studied. The tannin fractions were characterized by Fourier transform-infrared spectroscopy, thermogravimetric analysis, carbon nuclear magnetic resonance spectroscopy and matrix assisted laser desorption ionization time of flight mass spectrometry ( MALDI-TOF ). It was demonstrated that it is possible to extract reactive tannins from grape pomace in basic medium. The tannin extracts obtained by precipitation in acidic conditions display a high phenolic content (Stiasny number higher 95%) but low water solubility and low reactivity toward formaldehyde because of the formation of catechinic acid phlobatannins during the acidification step. The tannins extracts obtained by lyophilization of the liquid, despite of their lower phenolic contents, displayed promising properties for adhesive applications. The optimum temperature of the extraction process was 100 °C, reaction time was 120 min; the best concentration of reagent was 10% (w/w). It was also shown that addition of sulphite ions during the extraction step improved the process :y the introduction of a sulfonic group through sulfitation increased both tannin solubility and reactivity as a result from the opening of the heterocyclic ring during extraction The structure of grape pomace sulfited tannin extracts did not present noticeable discrepancy exception of the ratio of the opening pyran ring which was different as a function of the catalyst used. The opening of pyran ring during the tannins extraction seem to be more important by using Na2CO3 and NaHCO3 than when using NaOH. The FT-IR bands assigned to aromatic ring vibration and carbonyl groups were stronger and no bands attributed to sulfited groups were tested detected in acidified tannins compared to lyophilized tannins. The TG2 results showed that the weight lost of these tannin extracts mainly composed of two steps. The first step starts from room temperature to 200 °C. It is attributed to the mass lost of water and some easy-degraded small low molecules. The secondly steps which is the mainly degradation step of tannin extract samples from 200 to 400 °C. The results from 13C-NMR showed that condensed tannin extracts from grape pomace were consistent with dominant procyanidin units with a minor amount of prodelphinidin units that are linked together by a C4-C8 bond. Relatively low carbonhydrate and high catechinc acid content was observed in acidified tannins compared to lyophilized tannins. It was shown by MADI-TOF experiments that grape pomace tannin extracts are mainly composed of flavoinoid oligomers up to 6 repeating units in lyophilized tannins and 10 repeating units in acidified tannins respectively, with dominant procyanidin units. A small proportion of substitution with glucose and gallic acid was detected in procyanidin units of polyflavonoid oligomers. The degree of polymerization of acidified tannins is higher than lyophilized tannins. Two different formulations (nonfortified tannin adhesive and fortified with addition of 20% of polymeric 4, 4'-diphenyl methane diisocyanate (p-MDI)) were used to press one layer wood particle board. It was shown that the nature of the extraction reagent (NaOH, Na2CO3 or NaHCO3) greatly impacts the properties of the resins and the mechanical properties of the panel internal bonding strengths. The particleboards bonded by the tannins extracted using Na2CO3 as catalyst give the best performance and were good enough to pass relevant international standard specifications for interior grade panels. Formaldehyde emission of these panels was below the European Norm requirements (<= 6.5 mg/ 100g panel)