Online Laser Diagnostics for High-Temperature Chemistry in Biomass Combustion

Increasing concern over environment and new energy policies are driving the thermal heat and power industry towards new CO2 neutral fuels, such as biomass, and novel combustion schemes. Therefore new operational control and monitoring concepts are required to provide information of the combustion processes. Alkali elements and compounds have been identified to be one of the greatest challenges associated with thermal conversion of biomass as they cause severe operational problems in power plant boilers. In this Thesis, a new method to monitor temperature and O2 concentration during thermal conversion of biomass is developed. Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) is utilized to measure potassium reaction kinetics in lean combustion conditions, which provides valuable information for high temperature reaction models and simulations. The new information on potassium reaction kinetics with O2 enables online monitoring of temperature and O2 concentration utilizing the CPFAAS signal.Microwave-Assisted Laser-Induced Breakdown Spectroscopy (MW-LIBS) is demonstrated for the first time at ambient atmospheric conditions with impressive 93fold enhancement in limit of detection (LOD). MW-LIBS is further applied for online elemental monitoring during thermal conversion of biomass fuels as it improves detection of trace elements and reduces adverse self-absorption effects in high-concentration conditions. To enable the benefits of MW-LIBS, a novel burner for flame calibration is introduced. The burner allows calibration of LIBS for extended concentration range enabling quantitative elemental release monitoring during thermal conversion of different biomass fuels with varying elemental content. The elemental release behavior of biomass fuels is paramount for thermal conversion models and simulations that provide boiler operators and manufacturers crucial information on how to optimize the thermal processes and mitigate the alkali associated problems. Furthermore, as the novel MW-LIBS approach requires no or minimal sample preparation, it has great application potential for online elemental monitoring in different fields of science where low LOD or high sensitivity is required.The novel CPFAAS and MW-LIBS approaches provide simple and versatile methods for online high-temperature chemistry monitoring from laboratory-scale systems up to full-scale power plant boilers. Laser diagnostics will play a significant role in optimization and in process control of future thermal power generation as it enables development of online sensor networks to monitor and forecast the plant behavior

Online Laser Diagnostics for High-Temperature Chemistry in Biomass Combustion

Increasing concern over environment and new energy policies are driving the thermal heat and power industry towards new CO2 neutral fuels, such as biomass, and novel combustion schemes. Therefore new operational control and monitoring concepts are required to provide information of the combustion processes. Alkali elements and compounds have been identified to be one of the greatest challenges associated with thermal conversion of biomass as they cause severe operational problems in power plant boilers. In this Thesis, a new method to monitor temperature and O2 concentration during thermal conversion of biomass is developed. Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) is utilized to measure potassium reaction kinetics in lean combustion conditions, which provides valuable information for high temperature reaction models and simulations. The new information on potassium reaction kinetics with O2 enables online monitoring of temperature and O2 concentration utilizing the CPFAAS signal.Microwave-Assisted Laser-Induced Breakdown Spectroscopy (MW-LIBS) is demonstrated for the first time at ambient atmospheric conditions with impressive 93fold enhancement in limit of detection (LOD). MW-LIBS is further applied for online elemental monitoring during thermal conversion of biomass fuels as it improves detection of trace elements and reduces adverse self-absorption effects in high-concentration conditions. To enable the benefits of MW-LIBS, a novel burner for flame calibration is introduced. The burner allows calibration of LIBS for extended concentration range enabling quantitative elemental release monitoring during thermal conversion of different biomass fuels with varying elemental content. The elemental release behavior of biomass fuels is paramount for thermal conversion models and simulations that provide boiler operators and manufacturers crucial information on how to optimize the thermal processes and mitigate the alkali associated problems. Furthermore, as the novel MW-LIBS approach requires no or minimal sample preparation, it has great application potential for online elemental monitoring in different fields of science where low LOD or high sensitivity is required.The novel CPFAAS and MW-LIBS approaches provide simple and versatile methods for online high-temperature chemistry monitoring from laboratory-scale systems up to full-scale power plant boilers. Laser diagnostics will play a significant role in optimization and in process control of future thermal power generation as it enables development of online sensor networks to monitor and forecast the plant behavior

Online Laser Diagnostics for High-Temperature Chemistry in Biomass Combustion

Increasing concern over environment and new energy policies are driving the thermal heat and power industry towards new CO2 neutral fuels, such as biomass, and novel combustion schemes. Therefore new operational control and monitoring concepts are required to provide information of the combustion processes. Alkali elements and compounds have been identified to be one of the greatest challenges associated with thermal conversion of biomass as they cause severe operational problems in power plant boilers. In this Thesis, a new method to monitor temperature and O2 concentration during thermal conversion of biomass is developed. Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) is utilized to measure potassium reaction kinetics in lean combustion conditions, which provides valuable information for high temperature reaction models and simulations. The new information on potassium reaction kinetics with O2 enables online monitoring of temperature and O2 concentration utilizing the CPFAAS signal.Microwave-Assisted Laser-Induced Breakdown Spectroscopy (MW-LIBS) is demonstrated for the first time at ambient atmospheric conditions with impressive 93fold enhancement in limit of detection (LOD). MW-LIBS is further applied for online elemental monitoring during thermal conversion of biomass fuels as it improves detection of trace elements and reduces adverse self-absorption effects in high-concentration conditions. To enable the benefits of MW-LIBS, a novel burner for flame calibration is introduced. The burner allows calibration of LIBS for extended concentration range enabling quantitative elemental release monitoring during thermal conversion of different biomass fuels with varying elemental content. The elemental release behavior of biomass fuels is paramount for thermal conversion models and simulations that provide boiler operators and manufacturers crucial information on how to optimize the thermal processes and mitigate the alkali associated problems. Furthermore, as the novel MW-LIBS approach requires no or minimal sample preparation, it has great application potential for online elemental monitoring in different fields of science where low LOD or high sensitivity is required.The novel CPFAAS and MW-LIBS approaches provide simple and versatile methods for online high-temperature chemistry monitoring from laboratory-scale systems up to full-scale power plant boilers. Laser diagnostics will play a significant role in optimization and in process control of future thermal power generation as it enables development of online sensor networks to monitor and forecast the plant behavior

Online Laser Diagnostics for High-Temperature Chemistry in Biomass Combustion

Increasing concern over environment and new energy policies are driving the thermal heat and power industry towards new CO2 neutral fuels, such as biomass, and novel combustion schemes. Therefore new operational control and monitoring concepts are required to provide information of the combustion processes. Alkali elements and compounds have been identified to be one of the greatest challenges associated with thermal conversion of biomass as they cause severe operational problems in power plant boilers. In this Thesis, a new method to monitor temperature and O2 concentration during thermal conversion of biomass is developed. Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) is utilized to measure potassium reaction kinetics in lean combustion conditions, which provides valuable information for high temperature reaction models and simulations. The new information on potassium reaction kinetics with O2 enables online monitoring of temperature and O2 concentration utilizing the CPFAAS signal.Microwave-Assisted Laser-Induced Breakdown Spectroscopy (MW-LIBS) is demonstrated for the first time at ambient atmospheric conditions with impressive 93fold enhancement in limit of detection (LOD). MW-LIBS is further applied for online elemental monitoring during thermal conversion of biomass fuels as it improves detection of trace elements and reduces adverse self-absorption effects in high-concentration conditions. To enable the benefits of MW-LIBS, a novel burner for flame calibration is introduced. The burner allows calibration of LIBS for extended concentration range enabling quantitative elemental release monitoring during thermal conversion of different biomass fuels with varying elemental content. The elemental release behavior of biomass fuels is paramount for thermal conversion models and simulations that provide boiler operators and manufacturers crucial information on how to optimize the thermal processes and mitigate the alkali associated problems. Furthermore, as the novel MW-LIBS approach requires no or minimal sample preparation, it has great application potential for online elemental monitoring in different fields of science where low LOD or high sensitivity is required.The novel CPFAAS and MW-LIBS approaches provide simple and versatile methods for online high-temperature chemistry monitoring from laboratory-scale systems up to full-scale power plant boilers. Laser diagnostics will play a significant role in optimization and in process control of future thermal power generation as it enables development of online sensor networks to monitor and forecast the plant behavior

Microwave enhanced laser induced breakdown spectroscopy at atmospheric pressure

Antenna-coupled microwave radiation is used to enhance the sensitivity of laser induced breakdown spectroscopy (LIBS). Limit of detection on low laser pulse energy is enhanced by factor of 93. Improved detection is mainly due prolonged plasma lifetime which enables use of longer signal integration times

Detection of alkali path in a pilot-scale combustor using laser spectroscopy and surface ionization — From vapor to particles

Alkali species have been under intensive research in thermal conversion applications due to their abundance especially in biomass fuels. Alkali metals, sodium (Na) and potassium (K), are known to cause severe operational problems in combustion units, such as slagging, fouling, and corrosion. In this work, we present a monitoring method to follow alkali behavior from vapor to particles in a pilot-scale reactor. In our approach we combine Tunable Diode Laser Atomic Spectroscopy (TDLAS) for atomic potassium monitoring, Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) for KCl and KOH detection, and Surface Ionization Detection (SID) for monitoring of total flue gas and aerosol alkali content. Experiments were carried out in the Chalmers 100 kW oxy-fuel combustion unit that, during these experiments, used propane as fuel. Alkali species were injected as a water solution directly to the flame. In addition, SO2 was used to alter the conditions for alkali species formation injecting it directly to the combustion feed gas. Due to the alkali monitoring system described, we were able to monitor the alkali behavior during nucleation and sulfation processes. The conditions for dimer formation and heterogeneous nucleation were observed when the temperature conditions were changed by lowering the thermal input to the unit

Optical assessment of the spatial variation in total soil carbon using laser-induced breakdown spectroscopy

Soil carbon storage is a substantial factor in the global carbon cycle. Carbon sequestration in agricultural soils, and the assessment and validation of soil carbon storage, are crucial for the mitigation of agricultural greenhouse gas emissions and for steering towards sustainable farming practices. Enforcement and verification of carbon sequestration policies, methods, and models require extensive soil carbon monitoring capability. However, current conventional laboratory-based methods for soil carbon estimation are laborious, expensive, and time-consuming. In this work, we have developed a compact, robust, and field-capable experimental device based on laser-induced breakdown spectroscopy (LIBS) for the rapid assessment of total soil carbon content and its spatial distribution in mineral soils. The carbon content quantification was performed using a spectral line of carbon at a wavelength of 193.1 nm emitted from the laser-induced plasma plume. The LIBS measurements were performed on soil samples collected from 28 different locations and various depths (up to 1 m) of a test field cultivated with a forage legume (red clover - Trifolium pratense, L.) and grass (Timothy - Phleum pratense, L.) mixture in eastern Finland. A calibration model was established based on a limited and randomly chosen sample set and validated by comparing soil carbon estimates obtained from various locations in the test field using the dry combustion (LECO) method. Further, we demonstrate here the usefulness of LIBS methodology for mapping three-dimensional carbon distribution at the test field. We emphasize here that the calibration model can be generalized to other sample areas under similar soil type with a relative error of less than 10 % and possesses potential for fast on-site determination of spatial variation in total soil carbon, reducing substantially the need of time-consuming sample processing in laboratory. Therefore, LIBS enables frequent and extensive spatial and temporal soil carbon mapping and has the potential to become part of the future carbon monitoring network

Investigation on synthesis and properties of isosorbide based bis-GMA analogue

The aim of this work was to synthesize and investigate properties of a novel dimethacrylic monomer based on bioderived alicyclic diol—isosorbide. Its potential as a possible substitute of 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (BISGMA), widely used in dental restorative materials and suspected for toxicity was assessed. The novel monomer was obtained in a three-step synthesis. First, isosorbide was etherified by a Williamson nucleophilic substitution and subsequently oxidized to isosorbide diglycidyl ether (ISDGE). A triphenyl phosphine catalyzed addition of methacrylic acid to ISDGE resulted in 2,5-bis(2-hydroxy-3-methacryloyloxypropoxy)- 1,4:3,6-dianhydro-sorbitol (ISDGMA). The monomer obtained was photopolymerized using camphorquinone/2-(dimethylamino)ethyl methacrylate initiating system. Next, compositions with triethylene glycol dimethacrylate (TEGDMA) were prepared and polymerized. Double bond conversion, polymerization shrinkage and water sorption of resulting polymers were determined. Selected mechanical (flexular strength and modulus, Brinell hardness) and thermomechanical (DMA analysis) properties were also investigated. BISGMA based materials were prepared as reference for comparison of particular properties

Two Novel Parvoviruses in Frugivorous New and Old World Bats

Bats, a globally distributed group of mammals with high ecological importance, are increasingly recognized as natural reservoir hosts for viral agents of significance to human and animal health. In the present study, we evaluated pools of blood samples obtained from two phylogenetically distant bat families, in particular from flying foxes (Pteropodidae), Eidolon helvum in West Africa, and from two species of New World leaf-nosed fruit bats (Phyllostomidae), Artibeus jamaicensis and Artibeus lituratus in Central America. A sequence-independent virus discovery technique (VIDISCA) was used in combination with high throughput sequencing to detect two novel parvoviruses: a PARV4-like virus named Eh-BtPV-1 in Eidolon helvum from Ghana and the first member of a putative new genus in Artibeus jamaicensis from Panama (Aj-BtPV-1). Those viruses were circulating in the corresponding bat colony at rates of 7–8%. Aj-BtPV-1 was also found in Artibeus lituratus (5.5%). Both viruses were detected in the blood of infected animals at high concentrations: up to 10E8 and to 10E10 copies/ml for Aj-BtPV-1 and Eh-BtPV-1 respectively. Eh-BtPV-1 was additionally detected in all organs collected from bats (brain, lungs, liver, spleen, kidneys and intestine) and spleen and kidneys were identified as the most likely sites where viral replication takes place. Our study shows that bat parvoviruses share common ancestors with known parvoviruses of humans and livestock. We also provide evidence that a variety of Parvovirinae are able to cause active infection in bats and that they are widely distributed in these animals with different geographic origin, ecologies and climatic ranges

Ecological commonalities among pelagic fishes: comparison of freshwater ciscoes and marine herring and sprat

Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace and ciscoes, Coregonus spp.) and marine clupeids (herring, Clupea harengus, and sprat, Sprattus sprattus). We further elucidate potential effects of climate warming on these groups of fish based on the ecological features of coregonids and clupeids documented in the previous parts of the review. These freshwater and marine fishes share a surprisingly high number of similarities. Both groups are relatively short-lived, pelagic planktivorous fishes. The genetic differentiation of local populations is weak and seems to be in part correlated to an astonishing variability of spawning times. The discrete thermal window of each species influences habitat use, diel vertical migrations and supposedly also life history variations. Complex life cycles and preference for cool or cold water make all species vulnerable to the effects of global warming. It is suggested that future research on the functional interdependence between spawning time, life history characteristics, thermal windows and genetic differentiation may profit from a systematic comparison of the patterns found in either coregonids or clupeids