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| 2. |
- Furusjö, Erik, et al.
(author)
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Co-gasification of pyrolysis oil and black liquor - a new track for production of chemicals and transportation fuels from biomass
- 2015
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Conference paper (peer-reviewed)abstract
- Pressurized oxygen-blown entrained flow black liquor (BL) gasification, the Chemrec technology, has been demonstrated in a 3 MWth pilot plant in Piteå, Sweden for more than 25,000 h. The plant is owned and operated by Luleå University of Technology since 2013. It is well known that catalytic activity of alkali metals is important for the high reactivity of black liquor, which leads to a highly efficient BL gasification process. The globally available volume of BL is however limited and strongly connected to pulp production. By co-gasifying pyrolysis oil (PO) with BL it is possible to utilize the catalytic activity also for PO conversion to syngas. Adding PO leads to larger feedstock flexibility with the possibility of building larger biofuels plants based on BL gasification technology. This presentation summarizes new results from research activities aimed at developing and assessing the PO/BL co-gasification process. Results from laboratory experiments with PO/BL mixtures show that pyrolysis behavior and char gasification reactivity are similar to pure BL. This means that the decrease in the alkali metal concentration due to the addition of PO in the mixture does not decrease the reactivity. Pure PO is much less reactive. Mixing tests show that the fraction of PO that can be mixed into BL is limited by lignin precipitation as a consequence of PO acidity. Pilot scale PO/BL co-gasification experiments have been executed following design and construction of a new feeding system to allow co-feeding of PO with BL. The results confirm the conclusions from the lab scale study and prove that the co-gasification concept is practically applicable. Process performance of the pilot scale co-gasification process is similar to gasification of BL only with high carbon conversion and clean syngas generation. This indicates that the established BL gasification technology can be used for co-gasification of PO and BL without major modifications.
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| 3. |
- Furusjö, Erik, 1972-, et al.
(author)
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Mixing of Fast Pyrolysis Oil and Black Liquor : Preparing an Improved Gasification Feedstock
- 2016
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In: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 30:12, s. 10575-10582
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Journal article (peer-reviewed)abstract
- Co-gasification of fast pyrolysis oil and black liquor can be used to increase the size and improve profitability of pulp mill integrated biorefineries. The acids present in pyrolysis oil limit the amount that can be mixed into black liquor without causing precipitation of the black liquor dissolved lignin. This work shows that a simple model based on pyrolysis oil total acid number, including weak phenolic acids, can be used to predict the maximum pyrolysis oil fraction in blends. The maximum oil fraction is 20-25% for typical pyrolysis oil but can be increased up to at least 50% mass, corresponding to 70% energy, by addition of base. Thermodynamic equilibrium calculations are used to understand the effects of blend composition, including any added base, on the performance of a commercial scale gasification process. A substantial increase in overall gasification efficiency is observed with increasing pyrolysis oil fraction.
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| 4. |
- Iisa, Kristiina, et al.
(author)
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Chemical and physical characterization of aerosols from fast pyrolysis of biomass
- 2019
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In: Journal of Analytical and Applied Pyrolysis. - : Elsevier B.V.. - 0165-2370 .- 1873-250X. ; 142
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Journal article (peer-reviewed)abstract
- Biomass fast pyrolysis vapors contain a significant quantity of persistent aerosols, which can impact downstream processing by e.g. fouling of surfaces and deposition on downstream catalysts. In this study, aerosol concentrations and size distributions were measured by an impactor in two pyrolysis systems, a bench-scale fluidized-bed pyrolyzer and a pilot-scale cyclone pyrolyzer. In both units, the mass-based mode aerosol diameter was approximately 1 μm before aerosol collection devices in cooled vapors of 300–370 K but the number-based median was < 0.1 μm. Aerosols < 1 μm were formed and aerosols > 1 μm deposited during cooling of pyrolysis vapors from 620 to 370 K in the fluidized-bed pyrolysis system. The oil fraction collected from the aerosols constituted approximately 40 wt% of the total oils collected in both systems. Compared to the total collected oil, the oil fraction from the aerosols was enriched in lignin-derived components and anhydrosugars and had lower concentrations of low molecular weight cellulose derived oxygenates, such as hydroxyketones.
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| 5. |
- Khwaja, Salik, et al.
(author)
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Entrained flow gasification of torrefied lignocellulosic biomass
- 2016
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In: Papers of the 24TH European Biomass Conference. - Amsterdam : ETA Florence Renewable Energies. ; , s. 1138-1142, s. 1138-1142
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Conference paper (peer-reviewed)abstract
- An extensive evaluation program was carried out within the European SECTOR project to evaluate the feasibility of torrefied and densified biomass in available entrained flow gasifiers. Different entrained flow reactors (both atmospheric and pressurized) in different scales, from lab scale to a 240 MW industrial gasifier were used for evaluation of torrefied materials as feedstock. Total behaviours of the new fuel throughout the whole supply chains and the EFG systems were evaluated and documented, including process behaviours in terms of operation, gas quality, products of incomplete gasification, etc. Results showed a significant improvement in fuel properties in terms of storage, logistics, milling and feeding behaviour by torrefaction and densification. Entrained flow gasification of the torrefied biomass was also shown to be feasible without any major showstoppers, even improving the gasification processes. Production of tars and other products of incomplete gasification were often found significantly reduced during gasification of torrefied material.
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| 6. |
- Muala, Ala, et al.
(author)
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Acute exposure to wood smoke from incomplete combustion - indications of cytotoxicity
- 2015
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In: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 12
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Journal article (peer-reviewed)abstract
- Background: Smoke from combustion of biomass fuels is a major risk factor for respiratory disease, but the underlying mechanisms are poorly understood. The aim of this study was to determine whether exposure to wood smoke from incomplete combustion would elicit airway inflammation in humans. Methods: Fourteen healthy subjects underwent controlled exposures on two separate occasions to filtered air and wood smoke from incomplete combustion with PM1 concentration at 314 mu g/m(3) for 3 h in a chamber. Bronchoscopy with bronchial wash (BW), bronchoalveolar lavage (BAL) and endobronchial mucosal biopsies was performed after 24 h. Differential cell counts and soluble components were analyzed, with biopsies stained for inflammatory markers using immunohistochemistry. In parallel experiments, the toxicity of the particulate matter (PM) generated during the chamber exposures was investigated in vitro using the RAW264.7 macrophage cell line. Results: Significant reductions in macrophage, neutrophil and lymphocyte numbers were observed in BW (p < 0.01, < 0.05, < 0.05, respectively) following the wood smoke exposure, with a reduction in lymphocytes numbers in BAL fluid (< 0.01. This unexpected cellular response was accompanied by decreased levels of sICAM-1, MPO and MMP-9 (p < 0.05, < 0.05 and < 0.01). In contrast, significant increases in submucosal and epithelial CD3+ cells, epithelial CD8+ cells and submucosal mast cells (p < 0.01, < 0.05, < 0.05 and < 0.05, respectively), were observed after wood smoke exposure. The in vitro data demonstrated that wood smoke particles generated under these incomplete combustion conditions induced cell death and DNA damage, with only minor inflammatory responses. Conclusions: Short-term exposure to sooty PAH rich wood smoke did not induce an acute neutrophilic inflammation, a classic hallmark of air pollution exposure in humans. While minor proinflammatory lymphocytic and mast cells effects were observed in the bronchial biopsies, significant reductions in BW and BAL cells and soluble components were noted. This unexpected observation, combined with the in vitro data, suggests that wood smoke particles from incomplete combustion could be potentially cytotoxic. Additional research is required to establish the mechanism of this dramatic reduction in airway leukocytes and to clarify how this acute response contributes to the adverse health effects attributed to wood smoke exposure.
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| 7. |
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| 8. |
- Muala, Ala, et al.
(author)
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Respiratory Tract Deposition of Inhaled Wood Smoke Particles in Healthy Volunteers
- 2015
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In: Journal of Aerosol Medicine. - : Mary Ann Liebert Inc. - 1941-2711 .- 1941-2703. ; 28:4, s. 237-246
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Journal article (peer-reviewed)abstract
- Background: Respiratory tract deposition of air pollution particles is a key to their adverse health effects. This study was aimed to determine the size-resolved deposition fraction (DF) of sooty wood smoke particles in the lungs of healthy subjects. The type of wood smoke investigated is typical for household air pollution from solid fuels, which is among the largest environmental health problems globally.Methods: Twelve healthy volunteers inhaled diluted wood smoke from incomplete soot-rich combustion in a common wood stove. The DF of smoke particles (10–500 nm) was measured during three 15-min exposures in each subject during spontaneous breathing. Lung function was measured using standard spirometry.Results: The total DFs by particle number concentration were 0.34±0.08. This can be compared with DFs of 0.21–0.23 in healthy subjects during previous experiments with wood pellet combustion. For particle mass, the total DFs found in this study were 0.22±0.06. DF and breathing frequency were negatively correlated as expected from model calculations (p<0.01).Conclusions: The DF of the investigated sooty wood smoke particles was higher than for previously investigated particles generated during more efficient combustion of biomass. Together with toxicological studies, which have indicated that incomplete biomass combustion particles rich in soot and polycyclic aromatic hydrocarbons (PAHs) are especially harmful, these data highlight the health risks of inadequate wood combustion.
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| 9. |
- Simonsson, Johan, et al.
(author)
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Soot Concentrations in an Atmospheric Entrained Flow Gasifier with Variations in Fuel and Burner Configuration Studied Using Diode-Laser Extinction Measurements
- 2016
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In: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 30:3, s. 2174-2186
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Journal article (peer-reviewed)abstract
- Soot concentration measurements were performed using diode-laser extinction in an atmospheric air-blown entrained flow gasifier at two vertical levels. The gasifier was operated at different air-fuel equivalence ratios and with variations in fuel and burner configurations. Two fuels were investigated: wood powder and peat powder. These were burned using two burner configurations, one giving a rotating flow inside the gasifier (swirl), and one where the fuel and air were injected parallel with the gasifier axis (jet). The diode-laser measurements were performed at the wavelength 808 nm from which the soot concentrations were estimated, and additionally at 450 nm in order to gain insight into the spectral dependence of the extinction to estimate measurement quality. Additional diagnostic techniques were used, such as an electrical low-pressure impactor (ELPI) for soot size distributions and gas chromatography for species concentration measurements. The results show that wood powder produces higher soot concentrations than peat powder, especially at lower air-fuel equivalence ratios. Furthermore, the burner configuration had in general much less impact than the choice of fuel on the soot concentration.
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| 10. |
- Weiland, Fredrik, et al.
(author)
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Influence of process parameters on the performance of an oxygen blown entrained flow biomass gasifier
- 2015
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In: Fuel. - : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 153, s. 510-519
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Journal article (peer-reviewed)abstract
- Pressurized, O2 blown, entrained flow gasification of pulverized forest residues followed by methanol production is an interesting option for synthetic fuels that has been particularly investigated in the Nordic countries. In order to optimize gasification plant efficiency, it is important to understand the influence of different operating conditions. In this work, a pressurized O2 blown and entrained flow biomass gasification pilot plant was used to study the effect of four important process variables; (i) the O2 stoichiometric ratio (λ), (ii) the load of the gasifier, (iii) the gasifier pressure, and (iv) the fuel particle size. Commercially available stem wood fuels were used and the process was characterized with respect to the resulting process temperature, the syngas yield, the fuel conversion and the gasification process efficiency. It was found that CH4 constituted a significant fraction of the syngas heating value at process temperatures below 1400 °C. If the syngas is intended for catalytic upgrading to a synthetic motor fuel where CO and H2 are the only important syngas species, the process should be optimized aiming for a process temperature slightly above 1400 °C in order to reduce the energetic losses to CH4 and C6H6. This resulted in a cold gas efficiency (based only on CO and H2) of 70%. The H2/CO ratio was experimentally determined within the range 0.45-0.61. Thus, the syngas requires shifting in order to increase the syngas composition of H2 prior to fuel synthesis.
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