Sampling of tar from sewage sludge gasification using solid phase adsorption

Ortiz, I.; Pérez-Pastor, Rosa María; Hervás, José Ma Sánchez

doi:10.1007/s00216-012-5996-5

Cited by 11 publications

(9 citation statements)

References 20 publications

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“…The issue regarding inadequate sampling of benzene and toluene was reported previously by Ortiz el al. 38 and Horvat et al 32 Similar trends for secondary tar aromatics (one-and two-ring) were observed for other feedstock by Paasen and Kiel 9 and Dufour et al 37 who suggested that indene reforms to either benzene or naphthalene at temperatures between 800 and 900°C…”

Section: Energy and Fuelssupporting

confidence: 57%

Tars from Fluidized Bed Gasification of Raw and Torrefied Miscanthus x giganteus

Horvat¹,

Kwapińska²,

Xue³

et al. 2016

Energy Fuels

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The current study investigates the effect of temperature, equivalence ratio, and biomass composition on tar yields and composition. Torrefied and raw Miscanthus x giganteus (M×G) were used as biomass feedstocks in an atmospheric bubbling fluidized bed gasifier for experiments undertaken between 660 and 850°C and equivalence ratios from 0.18 to 0.32. Tar was sampled according to the solid phase adsorption method and analyzed by gas chromatography. There is an indication that torrefied M×G produces higher amounts of total GC-detectable tar as well as higher yields of 20 individually quantified tar compounds compared with those of raw M×G. Under similar gasification conditions (800°C and an equivalence ratio of 0.21), the total GC-detectable tar for torrefied M×G is approximately 42% higher than that for raw M×G. Higher tar yields are observed to be related to higher lignin and lower moisture content of torrefied M×G. The effect of temperature on tar yields is in good agreement with the literature. The highest yield of total GC-detectable tar, secondary tars, and tertiary-alkyl tars is observed between 750 and 800°C, followed by a decrease at higher temperature, whereas tertiary-polycyclic aromatics increase with the temperature over the range tested. The effect of equivalence ratio on total GC-detectable tar is not clear because data points vary significantly (up to 47%) over the range of equivalence ratios tested. Temperature is the main driver for tar production and its chemical composition; however, this study indicates that tar yields depend significantly on biomass composition.

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Section: Energy and Fuelssupporting

confidence: 57%

Tars from Fluidized Bed Gasification of Raw and Torrefied Miscanthus x giganteus

Horvat¹,

Kwapińska²,

Xue³

et al. 2016

Energy Fuels

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“…After a constant flow is ensured, a syngas volume of 100 mL is drawn over an amino-phase column (Supelco-Supelclean LC-NH 2 , 3 mL/500 mg) within 60 s using a syringe. Before and after sampling, the SPA columns are cooled, thus ensuring complete adsorption of the tars . To avoid condensation of tars, everything is electrically heated to above 200 °C in the sampling line.…”

Section: Methodsmentioning

confidence: 99%

“…Before and after sampling, the SPA columns are cooled, thus ensuring complete adsorption of the tars. 32 To avoid condensation of tars, everything is electrically heated to above 200 °C in the sampling line.…”

Section: Introductionmentioning

confidence: 99%

Air-Blown Entrained-Flow Gasification of Biomass: Influence of Operating Conditions on Tar Generation

et al. 2017

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The formation of tars in gasifiers based on fluidized- or fixed-bed technology is a major problem in biomass gasification. By pretreating biomass using hydrothermal carbonization (HTC), entrained-flow gasification becomes applicable. Oxygen-blown entrained-flow gasifiers (EFGs) operate at very high process temperatures, leading to an almost tar-free syngas. However, in decentralized small-scale units, preferably air is used as the gasification agent, which, in turn, causes lower gasifier temperatures. The specific impacts of air-blown gasification conditions and fuel properties of biocoal from HTC on tar formation require particular attention. Therefore, in this work, tar formation under air-blown gasification conditions is investigated using solid-phase adsorption at an electrically heated EFG with temperatures of 900–1300 °C and different air/fuel equivalence ratios λ. Furthermore, tars are measured in the hot syngas of an industrial-like autothermal EFG. HTC biocoals of various feedstocks (beech, biogenic residuals, municipal waste, and green waste), raw biomass (corn cobs), and fossil fuel (Rhenish lignite) are used as fuels. The results show that the main influencing parameter on tar loading in the syngas is the temperature, whereas the residence time and λ have less impact. However, in autothermal operation, the choice of λ controls the gasifier temperature and, thus, effectively affects the resulting tar loading. Identified tar compounds are mainly light polycyclic aromatic hydrocarbons, of which naphthalene is the most frequently occurring. At 1300 °C, tar loading is reduced to less than 0.2 g/Nm3, which allows for direct syngas use in internal combustion engines.

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“…With this approach, a detection limit of 2.5 mg Nm –3 has been reported without referring to any specific tar compound or tar group . Osipovs improved the SPA–GC measurement system by adding activated coconut charcoal as a second sorbent, to improve the sampling efficiency for benzene, toluene, and xylene (BTX compounds). , Ortiz Gonzales et al tested four different commercially prepacked cartridges for tar sampling from sewage sludge gasification and found Supelclean ENVICarb/NH 2 to be the most suitable stationary phase for sampling compounds such as naphthalene and benzene. The estimated breakthrough volume and adsorption capacity of the chosen cartridge was found to be higher than that required for real product-gas sampling.…”

Section: Introductionmentioning

confidence: 99%

Detailed Measurement Uncertainty Analysis of Solid-Phase Adsorption—Total Gas Chromatography (GC)-Detectable Tar from Biomass Gasification

et al. 2016

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Thermochemical gasification offers an attractive solution for the conversion of low-grade biomass and waste. However, practical experiences of the gasification processes reveal that the formation of tar is troublesome to continuous operation. Therefore, tar measurement protocols and tar reduction systems are priorities in the development of effective biomass gasification. Results of tar measurements often raise questions regarding their reliability and accuracy, because of calibration, sampling, and discrimination issues. The present work evaluates the solid phase adsorption (SPA)−gas chromatography (GC) measurement system for tar in product gas by comparing the mass spectroscopy detector (MSD) and flame ionization detector (FID) and their associated measurement uncertainty. The measurand is defined as the total GC detectable tar in a normal cubic meter of dry product gas when employing the common quantitation method, "quantitation as naphthalene". The GC-FID measurements were significantly higher than the GC-MSD measurements. Their overall uncertainties also vary by a significant margin. The measurement uncertainty analysis shows that this difference is taken into account by the uncertainty induced by the particulars of the GC-MSD and GC-FID measurement systems, where the relative expanded uncertainty is shown to be 109.4% and 35.0%, respectively. While a quantitative method based on a single calibration curve offers significant advantages, in terms of speed and simple quantitation of total GC detectable tar, such an approach introduces greater uncertainty within the reported results.

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Sampling of tar from sewage sludge gasification using solid phase adsorption

Cited by 11 publications

References 20 publications

Tars from Fluidized Bed Gasification of Raw and Torrefied Miscanthus x giganteus

Tars from Fluidized Bed Gasification of Raw and Torrefied Miscanthus x giganteus

Air-Blown Entrained-Flow Gasification of Biomass: Influence of Operating Conditions on Tar Generation

Detailed Measurement Uncertainty Analysis of Solid-Phase Adsorption—Total Gas Chromatography (GC)-Detectable Tar from Biomass Gasification

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