Calle Nilsson

Briquetting and combustion of spring-harvested reed canary-grass: effect of fuel composition

Abstract The purpose of this study was to increase the understanding how spring-harvested reed canary-grass briquettes with various chemical compositions with respect to ash content influence the formation of emissions during combustion in a 180 kW burner. Furthermore, an objective was to investigate possible ash problems during the combustion. Five fuels were used in the study consisting of three reed canary-grass samples with different ash contents from different growing sites in Sweden and additionally one of these materials was separated into a stem and leaf fraction. Flue gas emissions were measured and fuels and ashes were analysed. The variation in ash content did not affect the production of briquettes. Further, fuel containing only stem fraction showed the highest mechanical strength. The variation in ash content did not effect the flue gas emissions. The presented results showed low mean values for carbon monoxide ( mg / MJ , except one experiment) and particles in the flue gas ( mg / Nm 3 ) (no purification of flue gas). Emissions of nitrogen oxides were mg / MJ . The ash formed light voluminous big chunks where small parts showed a tendency to be sintered. The combustion experiments imply that spring-harvested reed canary-grass can be burned with success in combustion equipment that is designed for the differences in ash content.

Effect of OH radicals, relative humidity, and time on the composition of the products formed in the ozonolysis of α-pinene

The gas-phase ozonolysis of α-pinene at ppb levels were studied and the effects of OH radicals formed in the reaction, the relative humidity (RH), and time on the products formed were investigated. ...

Particle and handling characteristics of wood fuel powder: effects of different mills

Wood fuel powder cut in various types of impact mills and knife mills was characterised using sieve analysis, laser diffraction, image analysis and a funnel method for measuring the tendency to bridge. In addition, this study aims to find the relationship between particle characteristics, tendency to bridge and the type of mill. The different types of mills produced wood powder with different properties. Both sieve analysis and laser diffraction showed that impact mills produced wood powder with more fine particles than wood powder produced by knife mills. Image analysis showed that particle sizes and shapes differed between the two types of mills. The bridging tendency, measured as the size of a funnel opening needed for the powder to pass freely, was higher for powder produced by impact mills than by knife mills. The bridging tendency was found to be a combined effect of particle size and shape.

Separation of plutonium from soil and sediment prior to determination by inductively coupled plasma mass spectrometry

The purpose of this work was to develop an optimised sample-preparation procedure for the determination of Pu in soil/sediment with ICP-MS. To start with, several different procedures were screened for their ability to separate plutonium and remove uranium. After the screening, two methods were applied on one soil (IAEA Soil6) and two sediment reference materials (IAEA300 and IAEA135). These methods were based on separation of Pu using TEVA and a combination of UTEVA and TRU resins, followed by elution of Pu with 0.1% hydroxylethylidene diphosphonic acid (HEDPA). A comparison was also made between sample preparation based on acid-leaching and complete digestion using lithium borate fusion. The highest yield of Pu (80%) was found with the procedure consisting of fusion followed by TEVA, while the decontamination from U showed large variations (RSD varying from 16–52%) with all procedures. No difference in the recovery of Pu was found between the two sample preparation techniques. The results of the quantitative determination in low resolution of 239Pu and 240Pu from the UTEVA + TRU-separation were significantly higher than those obtained by the TEVA procedure. An analysis in higher mass resolution displayed interfering peaks in the mass-region of Pu, and lanthanide-containing polyatomic ions were found to be a likely cause for these interferences. The procedure based on lithium borate fusion and separation using the TEVA-resin avoided such interferences and was therefore tested for repeatability over time on IAEA300. The stability of the method was good (RSD = 2.49% (n = 8)), with the exception of one value being significantly higher than the others. This result was confirmed by analysis in higher mass-resolution, which indicates an inhomogeneous distribution of Pu in the reference material, despite a sample intake of about 1 g.

Reed canary-grass ash composition and its melting behaviour during combustion

Spring harvested reed canary-grass (RCG) with various chemical compositions was combusted in a 180 kW boiler. The ash melting behaviour was studied and the ash was analysed. Estimation of melting b ...

Drying of linseed oil paints: a laboratory study of aldehyde emissions

The effects of temperature, air humidity, air exchange rate, artificial light and fatty acid constitution on the emissions of aldehydes from linseed oil paint were investigated. Experiments were designed using a multivariate approach and data were analysed using different projection methods (principal component analysis, partial least-squares). Paints used were produced out of two different types of oils, where the fatty acid chains were either mainly linoleic or linolenic acid. The paints were applied onto glass plates and dried in chambers with a controlled climate. Aldehydes were sampled using silica gel impregnated with 2,4-dinitrophenylhydrazine and analysed by HPLC with UV and MS detection. Consecutive sampling of aldehydes every eighth hour as well as total aldehyde sampling was performed during the first 5 days after application of the paints. Hexanal and propanal were the dominating aldehydes emitted for linoleic and linolenic acid rich paint, respectively. Temperature and humidity sped up the emission process, giving a higher total amount of aldehydes. A higher amount of linoleic acid slowed down the emission process and gave higher total amounts of aldehydes. Artificial light and air exchange rate showed no significant effects on the emission process.

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

The enormous quantity of food wastes discarded annually forces a look into alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the current imperatives of society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for the recovery of added value compounds and detection by modern technologies and is an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels.

Direct Derivatization and Rapid GC-MS Screening of Nerve Agent Markers in Aqueous Samples

A rapid screening and identification method based on derivatization and gas chromatography mass spectrometry (GC-MS) has been developed for the detection of alkylphosphonic acids (APAs), the degradation products of organophosphorus nerve agents. The novel method described involves rapid (5 min) and direct derivatization of 25 microL aqueous sample using highly fluorinated phenyldiazomethane reagents (e.g., 1-(diazomethyl)-3,5-bis(trifluoromethyl)benzene). The APA derivatives are then screened by GC-MS negative ion chemical ionization (NICI) and identified by electron ionization (EI) mode. The conditions for the derivatization were optimized using statistical experimental design and multivariate data analysis. Method robustness was evaluated using aqueous samples from an official OPCW Proficiency Test and all APAs present in the sample were conclusively identified. Limits of detection for rapid screening using SIM NICI were between 5 and 10 ng/mL APA in aqueous sample, and for identification using full scan EI 100 ng/mL.

Combination of solid phase extraction and in vial solid phase derivatization using a strong anion exchange disk for the determination of nerve agent markers

Alkylphosphonic acids (APAs) are degradation products and chemical markers of organophosphorous (OP) nerve agents (chemical warfare agents). Anion exchange disk-based solid phase extraction (SPE) has been combined with in vial solid phase derivatization (SPD) and GC-MS analysis for the determination of APAs in aqueous samples. The optimization of critical method parameters, such as the SPD reaction, was achieved using statistical experimental design and multivariate data analysis. The optimized method achieved quantitative recoveries in the range from 83% to 101% (n=13, RSD from 4% to 10%). The method was sensitive, with LODs in SIM mode of 0.14 ppb, and demonstrated excellent linearity with an average R(2)>or=0.99 over the concentration range of 0.07-1.4 ppm in full scan mode and from 0.14 ppb to 14 ppb in SIM mode. For forensic applications, aqueous samples containing APAs at concentrations exceeding 14 ppb were concentrated and target analytes were successfully identified by spectral library and retention index matching. Method robustness was evaluated using aqueous samples from the official OPCW Proficiency Test (round 19) and all APAs present in the sample were conclusively identified. The SPE disk retained the underivatized APAs in a stable condition for extended periods of time. No significant losses of APAs from the disk were observed over a 36-day period. Overall, the method is well suited to the qualitative and quantitative analysis of degradation markers of OP nerve agents in aqueous matrices with simplicity, a low risk of cross-contamination and trace level sensitivity.

Briquetting of fractionated reed canary-grass for pulp production☆

Abstract A new harvesting system, delayed harvest, and the fibre properties of RCG (reed canary-grass, Phalaris arundinacea L.) makes RCG an interesting new source of raw material for the pulp and paper industry in northern Europe. Storage and transport are some of the limiting factors for using RCG as pulp raw material. The cost of transportation and storage is strongly related to the density of the raw material. To be able to guarantee year round available raw material to pulp mills, the logistic problems must be solved. This study examines low-density briquetting of RCG to improve logistics. To evaluate if the conditions in the briquetting process caused fibre damage, the properties of pulp from briquetted material was compared to those of pulp from non-briquetted material. Pulp produced from briquetted RCG had more fines as compared to the non-briquetted reference material. Hand sheets produced using pulp from briquetted RCG were thinner, denser, and had lower air permeability compared to the non-briquetted reference material. The strength properties of pulp made from briquetted RCG indicated little or no difference compared to the reference material. Briquetting of RCG can increase transport capacity, by taking full advantage of maximum load permitted on the vehicle. This improves the transport economy considerable.