Tar Samples Research Articles

Difference in tar reforming activities between biochar catalysts activated in H2O and CO2

• H 2 O-activated biochar has higher catalytic activity than CO 2 -activated biochar. • H 2 O-activated biochar has higher content of O-containing groups than that of CO 2 -activated biochar. • Addition of excess H 2 O during tar reforming can produce additional O-containing groups. This study investigates the difference in the activities between biochar catalysts activated in H 2 O and CO 2 for in situ tar reforming. The experiments were performed in a two-stage fluidized-bed/fixed-bed at 800 °C. Mallee wood biochar (106–250 μm) was activated in pure CO 2 or 15 vol% H 2 O balanced with Ar (15 vol. %H 2 O/Ar) for different times (0–50 mins) before being used as a catalyst for tar reforming. Based on the analysis of tar samples, it was found that H 2 O-activated biochar showed higher catalytic activity than CO 2 -activated biochar in both steam reforming and dry reforming of tar. Moreover, under otherwise identical conditions, reforming in steam was always more rapid than that in CO 2 regardless of the atmosphere in which biochar was activated. The characterisation of biochar showed that H 2 O activation resulted in a biochar with a higher content of O-containing functional groups and aromatic C-O structures than that from CO 2 activation. In addition, the content of O-containing functional groups and aromatic C-O structures of biochar after the steam reforming were higher than those after the dry reforming of tar. The different catalytic activities between the biochars activated by H 2 O and CO 2 could be attributed to the different amounts of O-containing functional groups and aromatic C-O structures in biochar generated by H 2 O or CO 2 activation. An extra supply of H 2 O plays an important role in improving and maintaining the catalytic activity of biochar during tar reforming.

The dissolution and microbial degradation of mobile aromatic hydrocarbons from a Pintsch gas tar DNAPL source zone

Source zones containing tar, a dense non-aqueous phase liquid (DNAPL), can contaminate groundwater for centuries. A common occurrence of tar is at former Pintsch gas factories. Little is known about the composition and fate of contaminants dissolving from Pintsch gas tar DNAPL. In this study, we determined the composition and water-soluble characteristics of mobile aromatic hydrocarbons and their biodegradation metabolites in the DNAPL contaminated groundwater at a former Pintsch gas tar plant. We assessed the factors that determine the fate of observed groundwater contaminants. Measured values of density (1.03-1.06kg/m3) and viscosity (18.6-39.4cP) were found to be relatively low compared to common coal tars. Analysis showed that unlike common coal tars phenanthrene is the primary component rather than naphthalene. Moreover, it was found that Pintsch gas tar contains a relatively high amount of light molecular aromatic hydrocarbon compounds, such as benzene, toluene, ethylbenzene and xylenes (BTEX). Less commonly reported components, such as styrene, ethyltoluenes, di-ethylbenzene, 1,2,4,5-tetramethylbenzene, were also detected in water extracts from Pintsch gas tar. Moreover, 46 relatively hydrophilic metabolites were found within the tar samples. Metabolites present within the tar suggest biodegradation of mobile aromatic Pintsch gas tar compounds occurred near the DNAPL. Based on eleven detected suspect metabolites, a novel anaerobic biodegradation pathway is proposed for indene. Overall, our findings indicate that Pintsch gas tar has higher invasive and higher flux properties than most coal tars due to its relatively low density, low viscosity and, high content of water-soluble compounds. The partitioning of contaminants from multi-component DNAPL into the aqueous phase and re-dissolution of their slightly less hydrophobic metabolites back from the aqueous phase into the DNAPL is feasible and demonstrates the complexity of assessing degradation processes within a source zone.

PAH sampling and quantification from woody biomass fast pyrolysis in a pyroprobe reactor with a modified tar sampling system

Abstract The present work focuses on the sampling procedure and quantification of the PAH yield from the fast pyrolysis of waste softwood. In particular, fast pyrolysis experiments were conducted using a CDS Pyroprobe 5200 at temperatures between 500 °C and 1000 °C, at a heating rate of 600 °C/s for a sample size of 30 mg. High performance liquid chromatography (HPLC) was used for the determination of the PAH compounds present in the liquid sample fraction, while a micro – GC was employed for the analysis of the main gaseous products (CO, CO2, CH4 and H2). An alternative tar sampling protocol was proposed, which employed the use of a cold trap (50 °C) and an isopropanol filled impinger bottle for the collection of the condensable products. The experiments were compared to heated foil reactor based pyrolysis tests within the same temperature range and heating rate, except for a slightly lower sample size (10 mg). The Pyroprobe and adapted sampling system proved to be more efficient regarding PAH capture and quantification compared to the heated foil reactor. Naphthalene, acenaphthylene and phenanthrene were the main PAH compounds detected. The PAH yields increased with pyrolysis temperature, up to values corresponding to roughly 0.2 wt% of the overall yield at 1000 °C. From the results it was derived that PAH evolution is mainly a product of secondary decomposition of primary tar, since the char yield stabilized for higher temperatures and the yields of CO, H2 and CH4 increased. Overall mass balance closure values were around 80 wt% on average. Char and gas yields were determined with high reproducibility, however gravimetric liquid analysis lacked due to the inability to gravimetrically measure the yield condensing in the impinger bottle. Future work is aimed on improving on this particular aspect. Overall, the alternative tar sampling system proposed was successful in the quantification of PAH from biomass fast pyrolysis experiments offering increased flexibility, accuracy and practicality of use.

Analytical assessment of tar generated during gasification of municipal solid waste: Distribution of GC–MS detectable tar compounds, undetectable tar residues and inorganic impurities

Abstract Tar, one of the most challenging impurities in the syngas generated from the gasification of municipal solid waste (MSW), can severely restrict its applicability in advanced utilization systems such as solid oxide fuel cells, gas engines and combined cycle gas turbines. Due to the complexity in sampling and analysis of tar, very limited studies have explored the development of comprehensive analytical procedure to provide insights into the distribution of GC–MS detectable tar compounds, GC–MS undetectable tar residues and inorganic impurities in the syngas from MSW gasification. In this study, Syngas generated from a downdraft fixed-bed gasifier (under different operating conditions) was sampled and analysed to understand the changes in the distributions of tar compounds and to verify the applicability of a sequential analytical procedure for syngas with different contents and distributions of tar and inorganic impurities. The procedure was developed to analyse and quantify the tar compounds and inorganic impurities in tar sampling solutions. The GC–MS analysis of three types of tar containing solutions (collected tar, gravimetric tar solution and evaporated condensate), gravimetric tar procedure (rotary evaporation and weighing), three separation/isolation methods (adsorption, dilution and decomposition) and quantification of inorganic compounds (cations and anions) were studied. With this sequential analytical procedure, enhanced detection and quantification (EDQ) of GC–MS detectable tar compounds at low concentration and correction on the GC–MS undetectable tar contents based on quantification of inorganic impurities were achieved. Distribution of tar and inorganic impurities was determined which revealed the impacts of operating conditions on syngas from MSW gasification.

Thermal treatment of tar generated during co-gasification of coconut shell and charcoal

Abstract Biomass-derived syngas is one of the most promising, feasible, clean and sustainable bioenergies widely produced through biomass gasification. However, tar content from syngas is essentially needed to be reduced for avoiding engines damage. Therefore, the aim of this study is to investigate the reduction efficiency of tar by performing thermal treatment at the temperature of 700 °C, 800 °C, 900 °C and 1000 °C in a digital Muffle furnace. The tar samples (before and after thermal treatments) were investigated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses while the morphological changes were examined using a scanning electron microscope coupled with energy-dispersive X-ray analysis. Experimental results show that tar reduction efficiency was significantly increased from 81.87% to 97.25% by applying thermal treatment from 700 °C to 1000 °C. The functional groups were reduced due to rising temperature. Furthermore, the roughness of tar was enhanced considerably with increasing temperature. Therefore, this tar-free syngas can be used as a clean and sustainable bioenergy for future energy demand.

Major tar compounds in raw producer gas and deposits from a small downdraft gasifier: Analysis and comparison

Tar is an undesirable product of biomass gasification. Tar analysis is a challenging task because it is a complex mixture. The objectives of this study are to identify and quantify the major tar compounds in raw producer gas and deposits from a 10 kW downdraft gasifier using cedar pellets. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the 16 tar samples from raw producer gas under varying airflow rates and four tar samples from the deposit inside the suction pump after long-term operation. The results showed that tar in raw producer gas and tar deposits consisted of about 46 and 28 major chemical compounds, respectively. Tar in raw producer gas was found to contain three main groups of substances, including acids/ketones with 32.1 wt%, heterocyclics with 30.0 wt%, and light poly-aromatic hydrocarbons (light PAHs) with 31.8 wt%. Heterocyclic and light PAH compounds dominated in tar deposits and accounted for 58.6 wt% and 36.2 wt%, respectively. It was observed that the tar condensation problem was dominated by the components and the molecular weight of tar compositions instead of the tar concentration. These findings are useful for optimizing the gasification process and developing the gas cleaning system for a small downdraft gasifier.

Geochemical Investigation of Tar Balls Collected in a Brazilian Beach Using Biomarkers, Ni/V, δ13C Ratios and Ultra-High Resolution FT‑ICR Mass Spectrometry

Representative tar balls collected in two distinct years (2012 and 2014) in a beach along the State of Bahia, northeastern Brazil, were geochemically characterized in order to identify correlations between them and investigate potential sources. Terpanes and steranes biomarkers (detected by gas chromatography coupled to mass spectrometry, GC-MS), carbon stable isotope ratio (δ13C), Ni and V ratios and polar compounds by Fourier transform ion cyclotron resonance mass spectrometry using electrospray ionization in negative mode (ESI(-) FT-ICR MS) were evaluated. Three Brazilian oil samples from distinct sources were assessed as possible spill sources, comparing their results with the tar ball samples. Using chemometric techniques, it was verified correlation between the two set of tar ball samples, suggesting same source. However, no correlation with the oil samples was observed, with different geochemical profile among them. The heteroatom class distribution displayed severe degradation levels for tar balls and its seems that photo-oxidation and biodegradation processes were further relevant. Tar ball samples show multiple classes, most oxygenated, and with one sample showing considerable relative abundance of N1 class, suggesting it is from a more recent oil spill. In brief, our results suggest that the region, with very sensitive ecosystem, is possibly subjected to frequent spills from the same source.

Thermal Effect on Co-product Tar Produced with Syngas Through Co-gasification of Coconut Shell and Charcoal

Lignocellulosic biomass generated syngas is one of the most promising alternative bioenergy for the fulfillment of future energy demand. However, the presence of tar in syngas may hindrance the direct uses as transportation and electricity generation purposes. Moreover, tar elimination from syngas is one of the major challenges that can cause fouling in pipes and engines. Thus, this study investigates the decomposition of tar compounds by thermal treatment at the temperature of 700 °C, 800 °C, 900 °C and 1000 °C under a digital Muffle Furnace. The raw tar samples (before and after thermal treatment) were investigated by fouriertransform infrared spectroscopy analysis and morphological changes were observed using a scanning electron microscope analysis. From this study, it was found that tar reduction efficiency was significantly affected by thermal treatment and increased from 81.87% to 97.25% at the required temperature from 700 °C to 1000 °C, respectively. Moreover, the roughness of tar increased significantly with increasing the temperature. The phenolic compounds were eliminated from raw tar due to thermal treatment up to 1000 °C. Therefore, this tar-free syngas can be used as clean and sustainable bioenergy for the future energy crisis.

Detection of tar brown carbon with a single particle soot photometer (SP2)

Abstract. We investigate the possibility that the refractory, infrared-light-absorbing carbon particulate material known as “tarballs” or tar brown carbon (tar brC) generates a unique signal in the scattering and incandescent detectors of a single particle soot photometer (SP2). As recent studies have defined tar brC in different ways, we begin by reviewing the literature and proposing a material-based definition of tar. We then show that tar brC results in unique SP2 signals due to a combination of complete or partial evaporation, with no or very little incandescence. Only a subset of tar brC particles exhibited detectable incandescence (70 % by number); for these particles the ratio of incandescence to light scattering was much lower than that of soot black carbon (BC). At the time of incandescence the ratio of light scattering to incandescence from these particles was up to 2-fold greater than from soot (BC). In our sample, where the mass of tar was 3-fold greater than the mass of soot, this led to a bias of <5 % in SP2-measured soot mass, which is negligible relative to calibration uncertainties. The enhanced light scattering of tar is interpreted as being caused by tar being more amorphous and less graphitic than soot BC. The fraction of the tar particle which does incandesce was likely formed by thermal annealing during laser heating. These results indicate that laser-induced incandescence, as implemented in the SP2, is the only BC measurement technique which can quantify soot BC concentrations separately from tar while also potentially providing real-time evidence for the presence of tar. In contrast, BC measurement techniques based on thermal–optical (EC: elemental carbon) and absorption (eBC: equivalent BC) measurements cannot provide such distinctions. The optical properties of our tar particles indicate a material similarity to the tar particles previously reported in the literature. However, more- and less-graphitized tar samples have also been reported, which may show stronger and weaker SP2 responses, respectively.

Performance of biochar as a catalyst for tar steam reforming: Effect of the porous structure

• The catalytic performance of char can be maintained at high temperatures (e.g. 850 °C). • Microporous chars deactivate faster than mesoporous chars. • At elevated temperatures activated char and regular char demonstrate similar performance. • Simulations showed that mesoporous chars conserve their catalytic activity for over 10 h. • Coke in micropores cannot be gasified even at high temperatures (e.g. 850 °C). The application of gasification to thermally treat biomass as carbon neutral resources has been constrained by the technical challenges associated with tar formations, which cause operational problems in downstream equipment for syngas processing. Catalysts, such as transition metals, calcined rocks and char, can be used to catalyse tar reforming. Biochars, which are naturally produced during biomass gasification, are particularly attractive as an alternative catalyst due to their catalytic functions, low cost and long endurance. Despite these promising characteristics, adequate knowledge on the relationship between the porous structure of biochar and its deactivation by coking during the steam reforming of tars is not available. In this work, the influence of the porous structure of biochar on its performance across time for reforming tar was investigated in a fixed-bed reactor, over a temperature range from 650 to 850 °C. Regular biochar and physically activated biochar from the same precursor biomass were employed as bed material. The tar samples were the composed mixture of benzene, toluene and naphthalene. Both fresh and spent catalysts were analysed with Brunauer-Emmet-Teller, t-plot, Fourier Transform Infrared and Scanning Electron Microscopy/Energy Dispersive Spectroscopy. Results showed that, while at moderate temperatures of 650 and 750 °C, the activated biochar offered a higher tar conversion but more severe deactivation than that of the regular biochar. At the high temperature of 850 °C, the difference in the catalytic performance between the two chars was negligible, and over 90% of the initial tar species were removed throughout the 3-hour long experiments. At 850 °C, the coke deposited in the meso- and macro-pores of both chars was gasified, leading to a stable catalytic performance of both chars. The results indicated that meso- and macro-porous biochars are resilient and active enough to become a viable option for tar steam reforming.

Instrumental improvements for the trace analysis of structural isomers of polycyclic aromatic hydrocarbons with molecular mass 302 Da

Polycyclic aromatic hydrocarbons (PAHs) are some of the most common environmental pollutants encountered worldwide. Eco-toxicological studies attribute a significant portion of the biological activity of PAH contaminated samples to the presence of high molecular weight PAHs (HMW-PAHs), i.e. PAHs with molecular mass (MM) greater than 300 Da. The research presented here focuses on the analysis of PAH isomers of MM 302 Da. This is not a trivial task. There are 23 isomers with MM 302 Da available to commercial and academic researchers. Many of them are difficult to separate in the chromatographic column and have virtually identical fragmentation patterns. The selectivity of HPLC absorption and fluorescence detectors is modest for resolving co-eluting isomers. Previous work in our lab demonstrated the potential of laser excited time-resolved Shpol'skii spectroscopy (LETRSS) for the analysis of 302 Da isomers in HPLC fractions. The main limitation of the technique was instrumental and due to the narrow range of excitation wavelengths of the tunable dye laser used for sample excitation. Herein, we remove this limitation with an optical parametric oscillator (OPO)-based wavelength tuning laser that covers the whole excitation range of 302 Da isomers. It is possible now to excite each isomer at its excitation wavelength for maximum fluorescence emission and reach limits of detection at the parts-per-trillion level (pg.mL-1). The excitation bandwidth of the OPO laser (0.2 nm) is a good match for the narrow excitation spectra of 302 Da isomers in n-octane. This feature, associated to unique vibrational fluorescence profiles and lifetime decays, allows for the unambiguous identification of co-eluting isomers in RPLC fractions. The same is true for their quantitative analysis in coal tar samples.

Kinetics of Thermal Decomposition of Tar in the Presence of Air and Nitrogen Gas

Thermogravimetric analysis (TGA) provides useful information, which can be used in thermal processing and conversion kinetic modeling of materials, including hydrocarbons. In the present study, a series of TGA experiments were conducted in the presence of air (combustion) and under inert conditions (pyrolysis) using nitrogen gas with the focus of obtaining quantitative information to compare thermal decomposition characteristics of the two processes. The analysis was performed at different gas injection rates (10–50 mL/min) and heating rates (10–30 °C/min) under non-isothermal conditions from 30 to 600 °C. It was observed that the gas injection rates did not have significant impact on the thermal decomposition of the tar sample. However, increasing the heating rate shifted the peak temperatures of the reactions to higher temperatures. In addition, the combustion process generally has a higher conversion and peak rate of conversion than the pyrolysis process. Moreover, the activation energy, Ea (kJ mol–1), obtained for the combustion process was observed to be higher than those of the pyrolysis.

Quantitative evaluation of n-alkanes, PAHs, and petroleum biomarker accumulation in beach-stranded tar balls and coastal surface sediments in the Bushehr Province, Persian Gulf (Iran)

Coastal areas within the Bushehr Province (BP), Persian Gulf, Iran, face great challenges due to the heavy organic contamination caused by rapid industrialization, and the presence of numerous oil fields. In addition, in 2014, a significant number of tar balls are found along the coasts of BP. A total of 96 samples (48 coastal sediments and 48 tar balls) were taken from eight sampling points at the BP coast during the summer of 2014. These samples were analyzed to identify the sources and characteristics of their organic matter using diagnostic ratios and fingerprint analysis based on the distribution of the source-specific biomarkers of n-alkanes, PAHs,1 hopanes and steranes. Mean concentration of n-alkanes (μg g-1 dw) and PAHs (ng g-1 dw) varied respectively from 405 to 220,626, and 267 to 23,568 in coastal sediments, while ranged respectively from 664 to 145,285 and 390 to 46,426 in tar balls. In addition, mean concentration of hopanes and steranes (ng g-1 dw) were between 18.17 and 3349 and 184.66 to 1578 in coastal sediments, whereas in tar balls were 235-1899 and 520-1504, respectively. Pri/Phy2 ratio was 0.25 to 1.51 (0.65) and 0.36 to 1 (0.63) in coastal sediment and tar ball samples, respectively, and the occurrence of UCM3 in both matrices, reflecting the petrogenic OM4 inputs and chronic oil contamination, respectively. The C30 and C29 homologues followed Gammacerane were detected in both matrices, in particular those collected from intensive industrial activities, suggesting petrogenic sources of OM. The coastal sediment PAHs profiles were significantly dominated by HMW5-PAHs in the Bahregan Beach (BAB) (78% of total PAHs), Bandare-Genaveh (GP) (66%), and Bandare-Bushehr (BUB) (61%) stations, while the Bashi Beach (BSB) (40%), Bandare-Kangan (KP) (57%), and Bandare-Asaluyeh (AP) (51%) stations exhibited higher proportion of LMW6-PAHs. PCA7 indicated that the tar ball and coastal sediment samples deposited along the Southwest of the BP beaches are most likely originated from the Abuzar oil. Based on the intensity of the anthropogenic activities, NPMDS8 analysis revealed that the GP, BAB, NNP, AP, and KP sampling sites had a high concentration of detected organic pollutants. To the best of our knowledge, this is the first study that investigates oil pollution in costal sediments and tar balls in the BP, providing insights in to the fate of oil in the coastal areas of the Persian Gulf, Iran.

Refinery bitumen and domestic unconventional heavy oil upgrading in supercritical water

Upgrading of three different bitumens from bottom of crude oil distillation columns, a type of bitumen from side stream of a propane deasphalting (PDA) unit and bitumen extracted from domestic tar sand samples was investigated in supercritical water (SCW). Coke suppression was highest for tar sand bitumens. Low vacuum residue (VR), high amounts of lighter ends, low aromatics and lower viscosity of the feed decreased coke yields even if there were high amounts of asphaltenes in the feed. At long reaction times, yields and selectivities were similar for different feeds. Red mud, Fluid Catalytic Cracking (FCC) spent catalyst, FeSO4, Fe2O3 and a blend of FCC spent and FeSO4 were investigated as catalytic additives. The coke yield was lowest with the FCC spent catalysts. Highest liquid yield was obtained using red mud. For all feeds, shot type cokes were obtained.

Determination of molecular mass 302 polycyclic aromatic hydrocarbons in Standard Reference Material 1597a by reversed-phase liquid chromatography and constant energy synchronous fluorescence spectroscopy

Abstract High-performance liquid chromatography with fluorescence detection is often used for the analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental extracts. Since fluorescence chromatograms are usually recorded at a single set of excitation and emission wavelengths, qualitative parameters for PAH identification are restricted to characteristic retention times. The research presented here explores the use of constant energy synchronous fluorescence spectroscopy (CESFS) for the analysis of co-eluting PAHs with similar chromatographic behaviors under normal and reversed-phase conditions. Twenty-one PAH isomers with molecular mass (MM, g/mol) 302 were studied. Synchronous fluorescence spectra were recorded under stop-flow conditions with the aid of a commercial HPLC system. PAHs were extracted from a coal tar sample (Standard Reference Material 1597a) and fractionated by normal-phase liquid chromatography (NPLC). Qualitative and quantitative analysis of NPLC fractions was carried out via reversed-phase liquid chromatography-CESFS (RPLC-CESFS). Of the 21 isomers investigated in the coal tar sample, 16 were spectrally identified in the absence of matrix interference. Three of the remaining isomers were tentatively identified in the presence of moderate spectral interference. Thirteen isomers were used to investigate the accuracy of the RPLC-CESFS approach. Mass fractions statistically equivalent to the NIST reported values (P = 95%; N1 = N2 = 3) were obtained for ten isomers ranging from 2.04 (dibenzo[a,h]pyrene) to 10.41 mg/kg (naphtho[2,1-a]pyrene). The non-destructive nature of CESFS provides an additional layer of selective and accurate information to the analysis of PAH isomers with MM 302.

The Effect of Hydrolysis on Properties of Soot and Tar During the Pyrolysis of Sewage Sludge

In this study, we evaluate the effect of hydrolysis treatment on the properties of tar and soot produced during the pyrolysis of sewage sludge at different operating temperatures (500–800 °C). The pyrolysis experiments were performed in a two-stage tubular fixed-bed reactor at atmospheric pressure. Raw sludge and hydrolysis-treated sludge (at pressure of 0.4 MPa and temperature 200 °C) samples were collected from local municipal sewage sludge treatment plant. The tar and soot samples obtained from pyrolysis at different temperatures were characterized by gas chromatography–mass spectrometry and scanning electron microscopy with energy dispersive X-ray spectroscopy, respectively. The results showed that increase in the pyrolysis temperature decreases the tar and soot yield for both raw and hydrolysis-treated sludge. The minimum tar yield was achieved with hydrolysis-treated sludge at 800 °C. The soot from raw sludge pyrolysis was of greater yield at high temperature than hydrolysis-treated sludge pyrolysis. The tar from pyrolysis of hydrolysis-treated sludge had more aliphatic character as compared to raw sewage sludge. The formation of heavy polycyclic aromatic hydrocarbons during pyrolysis of hydrolysis-treated sludge was lower at high temperatures than that of raw sludge. The aromatic hydrocarbons yield of hydrolysis-treated sludge was higher as compared to raw sludge at 800 °C.

Effect of Furnace Temperature on the Distribution of Tar during Gasification of Miscanthus

Biomass has been extensively recognised as a clean and sustainable energy source with the highest probability to substitute fossil fuel in the energy market. Its utilisation for energy generation is of particular interest to the world at large because of its potential to reduce global carbon dioxide emission. Concerning these considerations, gasification technology comes to the forefront of biomass conversion to various forms of energy for some reasons. Primarily, gasification offers a high flexibility in utilising different kinds of biomass feedstock to produce a combustible gas, making it more active process than pyrolysis and direct combustion. However, the major challenge associated with thermal gasification of biomass is tars and particulates formation. These compounds compromise the state of syngas, potentially harming end use systems especially those delicate to the quality of gas. In this research, tar sampling and analysis was performed based on a modified standard tar protocol followed by gas chromatography-flame ionisation detector (GC-FID) so as to quantify tar concentration in syngas produced from gasification of Miscanthus. Experiments was carried out at various furnace temperature in the range 350-650 , with temperature enhancement, the abundance of phenolic compounds increases.

Occurrence of European Tar Spot (Rhytisma acerinum) on Norway Maple (Acer platanoides) Causing Severe Infections in Minnesota

Rhytisma species causing tar spot of maple (Acer spp.) have a worldwide distribution wherever maples are found. In North America, three Rhytisma species are found affecting Acer: R. americanum (Hudler & Banik), R. punctatum (Pers.) Fr., and R. acerinum (Pers.) Fr. For a number of years, R. americanum was erroneously called R. acerinum, despite early reports that there may be two distinct species (Bracher 1924). Hudler et al. (1998) described R. americanum as a separate species that occurs on red (A. rubrum) and silver (A. saccharinum) maples, whereas R. acerinum is only found on Norway maple (A. platanoides) in North America. Norway maple was introduced to the United States in about 1856 from England (Nowak and Rowntree 1990), and since then it has been planted widely as an urban ornamental tree. It is currently considered one of the most common invasive exotic tree species in the United States. R. acerinum appears native to Europe and was introduced into the United States, with the first outbreaks of severe defoliation noted in New York (Hudler et al. 1987). R. acerinum infects Norway maple, causing lesions on leaves and black masses of stromatal tissue. During severe infections, multiple lesions coalesce and remaining leaf tissue becomes necrotic, leading to defoliation. However, there are conspicuous morphological differences between the three Rhytisma species in North America. In the late summer of 2017, we observed extensive infections on Norway maple in the Minneapolis/St. Paul, MN, area, including the maple collection at the University of Minnesota Landscape Arboretum, which includes several A. platanoides cultivars, most of which showed severe infection. Several cultivars (‘Olmstead’, ‘Emerald Queen’, and ‘Crimson King’) appeared to have more leaf necrosis, which affected large portions of the crown compared with others (‘Columnare’), indicating there may be differences in susceptibility. In addition, two sugar maple (A. saccharum) cultivars (‘Sweet Shadow’ and ‘Bailsta’) showed limited infection, as well as a hybrid (A. truncatum × A. platanoides ‘Keithsform’), which to our knowledge has not yet been reported as a host. Further observations and testing are needed to identify possible resistance in Norway maple cultivars. R. acerinum DNA was extracted directly from infected leaves by carefully excising small portions of tar spots and briefly surface sterilizing with a 5% bleach solution, rinsing with 95% EtOH, and air drying, followed by a CTAB extraction protocol, which provided the template for the amplification of the internal transcribed spacer (ITS) region of rDNA (Blanchette et al. 2016). A Bayesian phylogenetic analysis using ITS data showed that R. acerinum samples separated from other Rhytisma species that formed two clades. One Minnesota sample shared a clade with the type specimen (GenBank GQ253100) originating from Germany along with tar spot samples obtained from Germany for this study with a posterior probability of 100%. The other Minnesota samples grouped in a closely related clade with samples from Massachusetts, Maine, and New York. R. americanum grouped with strong support with the type species described by Hudler et al. (1998). R. acerinum has just started to cause severe infection in Minnesota, and it is important to recognize the damaging impacts of this pathogen across the regions where Norway maple is planted in order that specific control measures may be implemented.

Pelagic tar balls collected in the North Atlantic Ocean and Caribbean Sea from 1988 to 2016 have natural and anthropogenic origins

Tar balls are prevalent in oceans and the coastal environment; however, their origins are not well constrained on a global scale. To address this, we used gas chromatography to analyze the molecular composition of a unique set of 100 pelagic tar balls collected in the Western North Atlantic and Caribbean Sea between 1988 and 2016. Hierarchal cluster analysis (HCA) was employed to classify the samples into groups based on the relative proportions of resolved and unresolved hydrocarbon distributions. Additional analysis of polycyclic aromatic hydrocarbons revealed that 28% of samples originated from heavy fuel oils and therefore had anthropogenic origins consistent with the classifications based on HCA. Other samples examined could originate from anthropogenic or natural origins, such as natural seeps. This study provides a preliminary record of 100 classified pelagic tar ball samples and demonstrates an approach to determine their origin to the environment.

Characterization of Recycled Wood Chips, Syngas Yield, and Tar Formation in an Industrial Updraft Gasifier

In this study, the moisture content, calorific value, and particle size of recycled wood chips were measured. The wood chips were used to fuel an 8.5 MWth updraft gasifier to produce syngas for combustion in a steam-producing boiler. In-situ syngas composition and tar concentrations were measured and analyzed against biomass fuel properties. No efforts were made to adjust the properties of biomass or the routine operating conditions for the gasifier. A sampling device developed by CanmetENERGY-Ottawa (Ottawa, ON, Canada) was used to obtain syngas and tar samples. Wood chip samples fed to the gasifier were taken at the same time the gas was sampled. Results indicate that as the fuel moisture content increases from 20% to 35%, the production of CO drops along with a slight decrease in concentrations of H2 and CH4. Tar concentration increased slightly with increased moisture content and proportion of small fuel particles (3.15–6.3 mm). Based on the findings of this study, biomass fuel moisture content of 20% and particles larger than 6.3 mm (1/4″) are recommended for the industrial updraft gasifier in order to achieve a higher syngas quality and a lower tar concentration.