Sampling and characterization of high-molecular-weight polyaromatic tar compounds formed in the pressurized fluidized-bed gasification of biomass

Oesch, Pia; Leppämäki, Eero; Ståhlberg, Pekka

doi:10.1016/0016-2361(96)00113-5

Cited by 26 publications

(6 citation statements)

References 4 publications

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“…Polynuclear aromatic hydrocarbons eluted after polystyrenes of similar masses in dichloromethane. 58 The use of dimethylformamide in SEC has been investigated 33 for polyacrylonitrile and polyvinylpyrrolidinone. The mechanism of elution was considered to be other than by size exclusion, and the addition of LiBr did not improve the mechanism; the excluded material shifted to longer elution times in the presence of LiBr, and the profiles were considered to have been improved.…”

Section: Resultsmentioning

confidence: 99%

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Effect of LiBr Addition to 1-Methyl-2-pyrrolidinone in the Size-Exclusion Chromatography of Coal-Derived Materials

et al. 1998

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Two propositions relating to the interpretation of size-exclusion chromatograms (SEC) of coal-derived materials in 1-methyl-2-pyrrolidinone (NMP) have been examined. These were (i) that signal peaks showing up at exclusion (short retention time) limits of SEC columns are due to sample polarity alone and (ii) that shifts in SEC chromatograms to longer retention times, observed upon addition of LiBr to the eluent (NMP), are due to dissipation of ionic binding forces, causing disaggregation of polar clusters that would otherwise have appeared at retention times appropriate to larger molecular masses. In our experiments, effects due to polarity and molecular mass have been isolated by using two nonpolar samples (a naphthalene mesophase pitch and a mixture of fullerenes). In the presence of LiBr, precipitation of solute out of solution and shifts of chromatograms to longer retention times, unrelated to sample polarity, have been observed. A partial breakdown of the size exclusion mechanism was identified by the observed extension of chromatograms beyond the permeation limit of the column, similar to those observed when using eluents of insufficient solvent strength (e.g., THF, chloroform). Dosing LiBr into NMP sharply reduces the solvent power of NMP for coal-derived solutes. In the absence of LiBr, SEC chromatograms of the fullerene mixture, the naphthalene mesophase pitch, and its fractions separated by planar chromatography clearly showed significant signal under the “excluded” peak, entirely due to nonpolar material. The damage caused to the SEC column arising from precipitation of sample, in the presence of LiBr, was not permanent as had originally been feared. The balance of the evidence suggests that polarity of some molecules may cause shifts in their elution times to shorter values (larger apparent molecular masses) and that these may overlap with signal from large molecular mass material.

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Section: Resultsmentioning

confidence: 99%

“…In that work, standard compounds including polystyrenes were observed to elute with the same linear relation between log MM and elution volume, which covered a linear low-mass region down to 61 u with PAH eluting at slightly longer times. Polynuclear aromatic hydrocarbons eluted after polystyrenes of similar masses in dichloromethane …”

Section: Resultsmentioning

confidence: 99%

Effect of LiBr Addition to 1-Methyl-2-pyrrolidinone in the Size-Exclusion Chromatography of Coal-Derived Materials

et al. 1998

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“…Tar easily condenses on the surface of pipes and filters and may cause blockage and corrosion in the engines and turbines used in the application of the producer gas [8][9][10][11][12]. Hence, tar control and conversion is one of the most important technical barriers for a successful application of the technology in the power markets [10,13].…”

Section: Introductionmentioning

confidence: 99%

“…In fluidized bed gasification of biomass, the typical total tar content is in the range of 2-10 g/m 3 [9], and the main components are benzene and naphthalene [19].…”

Section: Introductionmentioning

confidence: 99%

Sampling of tar from sewage sludge gasification using solid phase adsorption

2012

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Sewage sludge is a residue from wastewater treatment plants which is considered to be harmful to the environment and all living organisms. Gasification technology is a potential source of renewable energy that converts the sewage sludge into gases that can be used to generate energy or as raw material in chemical synthesis processes. But tar produced during gasification is one of the problems for the implementation of the gasification technology. Tar can condense on pipes and filters and may cause blockage and corrosion in the engines and turbines. Consequently, to minimize tar content in syngas, the ability to quantify tar levels in process streams is essential. The aim of this work was to develop an accurate tar sampling and analysis methodology using solid phase adsorption (SPA) in order to apply it to tar sampling from sewage sludge gasification gases. Four types of commercial SPA cartridges have been tested to determine the most suitable one for the sampling of individual tar compounds in such streams. Afterwards, the capacity, breakthrough volume and sample stability of the Supelclean™ ENVI-Carb/NH(2), which is identified as the most suitable, have been determined. Basically, no significant influences from water, H(2)S or NH(3) were detected. The cartridge was used in sampling real samples, and comparable results were obtained with the present and traditional methods.

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“…Each institution working around the world in this field has been using its own method of tar sampling and analysis. So, when speaking of tar each one can have had a different measure of it (Narva ´ez et al, 1996;Oesch et al, 1996;Milne et al, 1997). Tar, in biomass gasification, has been thus a relative or subjective concept and lump but, to advance in the field, we must use this term.…”

Section: Introductionmentioning

confidence: 99%

Biomass Gasification with Air in Fluidized Bed: Reforming of the Gas Composition with Commercial Steam Reforming Catalysts

Corella

Orío

Aznar

1998

Ind. Eng. Chem. Res.

144

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Four commercial catalysts for steam reforming of higher hydrocarbons (naphthas) and three for steam reforming of light hydrocarbons are tested for hot gas clean up and upgrading in biomass gasification with air in fluidized bed. The catalysts used originate from four manufacturers: BASF AG, ICI-Katalco, Haldor Topsoe a/s, and United Catalysts Inc. The work is performed in a small pilot plant (1−2 kg of biomass fed/h) with three reactors in series: gasifier, guard bed of dolomite, and full flow catalytic bed. Samples of gas are taken before and after the catalytic bed at different times-on-stream. It is shown how the H2, CO, CO2, CH4 and steam contents in the flue gas change because of the catalytic bed approaching contents near to the ones corresponding to the equilibrium state. Variations in the heating value of the gas and gas yield as a result of the catalytic bed are also reported.

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Sampling and characterization of high-molecular-weight polyaromatic tar compounds formed in the pressurized fluidized-bed gasification of biomass

Cited by 26 publications

References 4 publications

Effect of LiBr Addition to 1-Methyl-2-pyrrolidinone in the Size-Exclusion Chromatography of Coal-Derived Materials

Effect of LiBr Addition to 1-Methyl-2-pyrrolidinone in the Size-Exclusion Chromatography of Coal-Derived Materials

Sampling of tar from sewage sludge gasification using solid phase adsorption

Biomass Gasification with Air in Fluidized Bed: Reforming of the Gas Composition with Commercial Steam Reforming Catalysts

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