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Augsburg, Germany

Deuerling C.F.,Helmholtz Center Munich | Maguhn J.,Helmholtz Center Munich | Nordsieck H.O.,Bifa Environmental Institute | Warnecke R.,GKS Gemeinschaftskraftwerk Schweinfurt GmbH | And 2 more authors.
Aerosol Science and Technology | Year: 2010

A measurement system was developed to sample and analyze the particle and gas phase of high temperature combustion aerosols up to a particle aerodynamic diameter of approximately 3 mm. The rapid changes of aerosol composition and concentration caused by the inhomogeneous fuel and changing burning conditions were accommodated by a combined measurement of both gas and particle phase and a synchronous measurement of two identical systems at two different positions at the boiler. Based on works reported earlier, an air-cooled dilution probe was designed and adapted to the corrosive composition of the combustion aerosol by use of a silica glass inlet and a ceramic porous tube diluter (PTD). Directly behind the probe, the raw gas is passing a cyclone which precipitates the coarse particles >25 μm, and is then split into a gas analysis and a particle analysis branch. The particle branch, after further dilution and cooling to ambient temperature, is split for a simultaneous analysis by an APS and a low pressure impactor (ELPI or BLPI). The whole sampling line is conditioned to 300°C until final dilution and cooling to ambient temperature. The measurement system was employed at different incineration plants between 220°C and 950°C for various experiments, e.g., time resolved concentration analysis during soot blowing cleaning routine. The mass concentration balance, including the content of the inlet, achieved a 92% match of the total slag mass balance of the investigated plant. Source


Brandt C.,Bavarian Center for Applied Energy Research | Kunde R.,Bavarian Center for Applied Energy Research | Dobmeier B.,Bavarian Center for Applied Energy Research | Schnelle-Kreis J.,Helmholtz Center Munich | And 8 more authors.
Atmospheric Environment | Year: 2011

Ambient PM10 concentration monitoring as well as dispersion calculations were conducted to determine the influence of emissions from domestic heating on ambient PM10 concentrations in Augsburg, Germany. Based on the Augsburg emission inventory for domestic heating an average emission factor for particulate emissions from the combustion of different solid fuels (wood logs, pellets, briquettes) in different types of stoves under various combustion conditions was found to be 120 mg MJ-1 related to energy input. Hence an emission model as well as a wind field model were created for dispersion calculation of the emitted PM from wood combustion within Augsburg. The results of the dispersion calculation concurred with the ambient PM10 monitoring data measured during the heating period 2007/2008. One result found that in residential areas with a high density of stoves the observed maximum concentration value of 9 μg m-3 from wood combustion was up to 50% higher than in the city center. Ambient monitoring as well as dispersion calculation have shown a significant influence of wood combustion on ambient PM10 concentrations in Augsburg. Based on these results the impact of wood combustion in a city can be estimated. © 2011 Elsevier Ltd. Source


Dragan G.C.,Helmholtz Center Munich | Dragan G.C.,University of Rostock | Breuer D.,Institute for Occupational Safety and Health Alte | Blaskowitz M.,Institute for Occupational Safety and Health Alte | And 10 more authors.
Environmental Sciences: Processes and Impacts | Year: 2015

Semi-volatile (SV) aerosols still represent an important challenge to occupational hygienists due to toxicological and sampling issues. Particularly problematic is the sampling of hazardous SV that are present in both particulate and vapour phases at a workplace. In this study we investigate the potential evaporation losses of SV aerosols when using off-line filter-adsorber personal samplers. Furthermore, we provide experimental data showing the extent of the evaporation loss that can bias the workplace risk assessment. An experimental apparatus consisting of an aerosol generator, a flow tube and an aerosol monitoring and sampling system was set up inside a temperature controlled chamber. Aerosols from three n-alkanes were generated, diluted with nitrogen and sampled using on-line and off-line filter-adsorber methods. Parallel measurements using the on-line and off-line methods were conducted to quantify the bias induced by filter sampling. Additionally, two mineral oils of different volatility were spiked on filters and monitored for evaporation depending on the samplers flow rate. No significant differences between the on-line and off-line methods were detected for the sum of particles and vapour. The filter-adsorber method however tended to underestimate up to 100% of the particle mass, especially for the more volatile compounds and lower concentrations. The off-line sampling method systematically returned lower particle and higher vapour values, an indication for particle evaporation losses. We conclude that using only filter sampling for the assessment of semi-volatiles may considerably underestimate the presence of the particulate phase due to evaporation. Thus, this underestimation can have a negative impact on the occupational risk assessment if the evaporated particle mass is no longer quantified. This journal is © The Royal Society of Chemistry 2015. Source


Dragan G.C.,Helmholtz Center Munich | Dragan G.C.,University of Rostock | Karg E.,Helmholtz Center Munich | Karg E.,VI Systems | And 10 more authors.
Environmental Engineering and Management Journal | Year: 2014

The process of semi-volatile aerosol particle evaporation was studied with respect to both computational and experimental approaches. A Sinclair-La Mer type aerosol generator was used to produce monodisperse particles from four n-alkanes (tetradecane, hexadecane, octadecane, eicosane) while particle sizing and FID measurements were applied to quantify particleand vapor mass and their subsequent phase distribution. Aerosol dilution and later stationary analyses in a flow tube at two time intervals enabled an experimental study on particle evaporation into a finite and constant volume. Experiments carried out for nalkanes at 25°C showed that tetradecane particles evaporated almost completely within 3 seconds whereas eicosane particles remained nearly unchanged. A diffusion based model that accounts for the evaporation dynamic of variously concentrated particle populations was developed. Good agreement between experimental and computational results was found, with relative deviations being less than 20% for the majority of the experiments. The study has shown that evaporation of semi-volatile nalkane aerosol particles can be successfully predicted using the diffusion based model. © 2014, (publisher). All rights reserved. Source


Fendt A.,University of Rostock | Fendt A.,Helmholtz Center for Environmental Research | Fendt A.,University of Augsburg | Streibel T.,University of Rostock | And 8 more authors.
Energy and Fuels | Year: 2012

In the current discussion about future energy and fuel supply based on regenerative energy sources, the so-called second-generation biofuels represent a vitally important contribution for the provision of carbon-based fuels. In this framework, at the Karlsruhe Institute of Technology (KIT), the bioliq process has been developed, by which biomass is flash-pyrolyzed at 500 °C for the production of so-called biosyncrude, a suspension of the pyrolysis liquids and the remaining biochar. However, little is known about the composition of the pyrolysis gases in this process with regard to different biomass feedstock and process conditions, and the influence on the subsequent steps, namely, the gasification and subsequent production of biofuels or base materials. Time-of-flight mass spectrometry (TOFMS) with two soft (i.e., fragmentation free) photoionization techniques was for the first time applied for on-line monitoring of the signature organic compounds in highly complex pyrolysis gases at a technical pyrolysis pilot plant at the KIT. Resonance-enhanced multiphoton ionization with TOFMS using UV laser pulses was used for selective and sensitive detection of aromatic species. Furthermore, single-photon ionization using VUV light supplied by an electron beam-pumped excimer light source was used to comprehensively ionize (nearly) all organic molecules. For the miscellaneous biomass feeds used, distinguishable mass spectra with specific patterns could be obtained, mainly exhibiting typical pyrolytic decomposition products of (hemi)cellulose and lignin (phenol derivatives), and nitrogen-containing compounds in some cases. Certain biomasses are differentiated by their ratios of specific groups of phenolic decomposition products. Therefore, principal component and cluster analysis describes the varied pyrolysis gas composition for temperature variations and particularly for different biomass species. The results can be integrated in the optimization of the bioliq process. © 2011 American Chemical Society. Source

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