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  • 1. Andersson, J.
    et al.
    Lundgren, J.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Methanol production via pressurized entrained flow biomass gasification: Techno-economic comparison of integrated vs. stand-alone production2014In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 64, p. 256-268Article in journal (Refereed)
    Abstract [en]

    The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11-18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR. © 2014 Elsevier Ltd.

  • 2. Boman, Christoffer
    et al.
    Nordin, Anders
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Westerholm, R.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Evaluation of a constant volume sampling setup for residential biomass fired appliances: Influence of dilution conditions on particulate and PAH emissions2005In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 29, no 4, p. 258-268Article in journal (Refereed)
    Abstract [en]

    Increased concerns about particulate matter (PM) and polycyclic aromatic hydrocarbons (PAH) emissions from residential biomass combustion and their potential health effects, motivates detailed emission measurements under controlled conditions. Traditional sampling in raw flue gases can suffer from drawbacks mainly related to transient flows and the condensable nature of organic compounds. Whole flow dilution with constant volume sampling (CVS) is an alternative method but different sampling conditions may, however, influence the emission characteristics. The objective was to design a CVS system for emission measurements in residential biomass fired appliances and determine the influence of dilution sampling conditions on the characteristics and distributions of PM and PAH. Softwood pellets were combusted in a pellet stove with variations in; dilution ratio (3-7x), sampling temperature (45-75°C), dilution tunnel residence time (2-4 s) and fuel load (2.3 and 4.8 kW) according to a statistical experimental design. The sampling conditions did not influence either the emission concentrations of PM, CO and NO or the particle size distribution. Variations in residence time had no significant effect on any studied emission parameter. However, increased concentrations of organic gaseous carbon (OGC) and PAH were observed with increased dilution ratio. The distribution between particulate and semivolatile phase was influenced for 12 of the 37 analyzed PAH compounds, mainly by increased fractions of semivolatile material at higher sampling temperature. No influence of sampling temperature was observed for the concentrations of PAHtot or the dominating PAH compounds, i.e. phenanthrene, fluoranthene and pyrene. The results together with practical considerations also suggest sampling at 50±5°C and 3-4 times dilution as robust and applicable conditions in the presently designed setup. © 2005 Elsevier Ltd. All rights reserved.

  • 3. Boman, Christoffer
    et al.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Westerholm, R.
    Bostrom, D.
    Nordin, Anders
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Stove performance and emission characteristics in residential wood log and pellet combustion: Part 1: Pellet stoves2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 1, p. 307-314Article in journal (Refereed)
    Abstract [en]

    Stove performance, characteristics, and quantities of gaseous and particulate emissions were determined for two different pellet stoves, varying fuel load, pellet diameter, and chimney draft. This approach aimed at covering variations in emissions from stoves in use today. The extensive measurement campaign included CO, NOx, organic gaseous carbon, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. At high load, most emissions were similar. For stove B, operating at high residual oxygen and solely with primary air, the emissions of PMtot and particle numbers were higher while the particles were smaller. Lowering the fuel load, the emissions of CO and hydrocarbons increased dramatically for stove A, which operated continuously also at lower fuel loads. On the other hand for stove B, which had intermittent operation at lower fuel loads, the emissions of hydrocarbons increased only slightly lowering the fuel load, while CO emissions increased sharply, due to high emissions at the end of the combustion cycle. Beside methane, dominating VOCs were ethene, acetylene, and benzene and the emissions of VOC varied in the range 1.1-42 mg/MJfuel. PAH emissions (2-340 μg/MJfuel) were generally dominated by phenanthrene, fluoranthene and pyrene. The PM tot values (15-45 mg/MJfuel) were in all cases dominated by fine particles with mass median diameters in the range 100-200 nm, peak mobility diameters of 50-85 nm, and number concentrations in the range 4 × 1013 to 3 × 1014 particles/MJfuel. During high load conditions, the particulate matter was totally dominated by inorganic particles at 15-25 mg/MJfuel consisting of potassium, sodium, sulfur, and chlorine, in the form of K2SO4, K 3Na(SO4)2, and KCl. The study shows that differences in operation and modulation principles for the tested pellet stoves, relevant for appliances in use today, will affect the performance and emissions significantly, although with lower scattering in the present study compared to compiled literature data. © 2011 American Chemical Society.

  • 4. Brus, E.
    et al.
    Ohman, M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Nordin, Anders
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Hedman, Henry
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Eklund, A.
    Bed agglomeration characteristics of biomass fuels using blast-furnace slag as bed material2004In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 18, no 4, p. 1187-1193Article in journal (Refereed)
    Abstract [en]

    Agglomeration of bed material may cause severe operating problems during fluidized bed combustion. The attack or coating layers that are formed on the bed particles during combustion play an important role in the agglomeration process. To reduce bed agglomeration tendencies, alternative bed materials may be used. In this paper, bed agglomeration characteristics during the combustion of biomass fuels using a relatively new bed material (iron blast-furnace slag) as well as ordinary quartz sand were determined. Controlled agglomeration tests lasting 40 h, using five representative biomass fuels (bark, olive residue, peat, straw, and reed canary grass) were conducted in a bench-scale fluidized bed. The bed materials and agglomerates were analyzed using SEM/EDS and X-ray diffraction. Chemical equilibrium calculations were performed to interpret the experimental findings. The results showed that blast-furnace slag had a lower tendency to agglomerate than quartz sand for most of the fuels. The quartz particles showed an inner attack layer more often than did the blast-furnace slag. The blast-furnace slag had a lower tendency to react with elements from the fuel. The outer coating layer had similar characteristics and thickness for both bed materials when the same fuel was combusted. However, the inner attack layer thickness was larger for quartz particles. SEM/EDS analyses of the agglomerates showed that the inner Ca-K-silicate-rich attack layer was responsible for the agglomeration of quartz sand. The composition of blast-furnace slag agglomerate was similar to the outer coating layer. Chemical equilibrium calculations showed that the original composition of the blast-furnace slag was close to the equilibrium composition, and hence there was no major driving force for reactions between that bed material and K and Ca from the fuel. The homogeneous silica-rich attack layer (with a low melting temperature) was not formed to the same extent for blast-furnace slag, thus explaining the lower bed agglomeration tendency. © 2004 American Chemical Society.

  • 5.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gronberg, C.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Risberg, M.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Spatially resolved measurements of gas composition in a pressurised black liquor gasifier2009In: Environmental Progress & Sustainable Energy, ISSN 1944-7442, E-ISSN 1944-7450, Vol. 28, no 3, p. 316-323Article in journal (Refereed)
    Abstract [en]

    Black liquor gasification is a new process for recovery of energy and chemicals in black liquor from the Kraft pulping process. The process can be combined with catalytic conversion of syngas into motor fuels. The potential for motor fuel production from black liquor in Sweden is to replace about 25% of the current consumption ofgasoline and diesel. For Finland the figure is even higher while for Canada it is about 14% and for the USA about 2%. © 2009 American Institute of Chemical Engineers Environ Prog, 28: 316-323, 2009.

  • 6.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Iisa, K
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Computational fluid dynamics simulations of raw gas composition from a black liquor Gasifier: Comparison with experiments2011In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 25, no 9, p. 4122-4128Article in journal (Refereed)
    Abstract [en]

    Pressurized entrained flow high temperature black liquor gasification can be used as a complement or a substitute to the Tomlinson boiler used in the chemical recovery process at kraft pulp mills. The technology has been proven on the development scale, but there are still no full scale plants. This work is intended to aid in the development by providing computational tools that can be used in scale up of the existing technology. In this work, an existing computational fluid dynamics (CFD) model describing the gasification reactor is refined. First, one-dimensional (1D) plug flow reactor calculations with a comprehensive reaction mechanism are performed to judge the validity of the global homogeneous reaction mechanism used in the CFD simulations in the temperature range considered. On the basis of the results from the comparison, an extinction temperature modification of the steam-methane reforming reaction was introduced in the CFD model. An extinction temperature of 1400 K was determined to give the best overall agreement between the two models. Next, the results from simulations of the flow in a 3 MW pilot gasifier with the updated CFD model are compared to experimental results in which pressure, oxygen to black liquor equivalence ratio, and residence time have been varied. The results show that the updated CFD model can predict the main gas components (H 2, CO, CO2) within an absolute error of 2.5 mol %. CH 4 can be predicted within an absolute error of 1 mol %, and most of the trends when process conditions are varied are captured by the model. © 2011 American Chemical Society.

  • 7. Carlsson, Per
    et al.
    Lycksam, H.
    Gren, P.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Iisa, K.
    High-speed imaging of biomass particles heated with a laser2013In: Journal of Analytical and Applied Pyrolysis, 2013, Vol. 103, p. 278-286Conference paper (Refereed)
    Abstract [en]

    In this work two types of lignocellulosic biomass particles, European spruce and American hardwood (particle sizes from 100 μm to 500 μm) were pyrolysed with a continuous wave 2 W Nd:YAG laser. Simultaneously a high-speed camera was used to capture the behavior of the biomass particle as it was heated for about 0.1 s. Cover glasses were used as a sample holder which allowed for light microscope studies after the heating. Since the cover glasses are not initially heated by the laser, vapors from the biomass particle are quenched on the glass within about 1 particle diameter from the initial particle. Image processing was used to track the contour of the biomass particle and the enclosed area of the contour was calculated for each frame.

    The main observations are: There is a significant difference between how much surface energy is needed to pyrolyses the spruce (about 75% more) compared to the hardwood. The oil-like substance which appeared on the glass during the experiment is solid at room temperature and shows different levels of transparency. A fraction of this substance is water soluble. A brownish coat is seen on the unreacted biomass. The biomass showed insignificant swelling as it was heated. The biomass particle appears to melt and boil at the front that is formed between the laser beam and the biomass particle. The part of the particle that is not subjected to the laser beam seems to be unaffected.

  • 8.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Ma, C.
    Molinder, Roger
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Weiland, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Ohman, M.,
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Slag formation during oxygen-blown entrained-flow gasification of stem wood2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 11, p. 6941-6952Article in journal (Refereed)
    Abstract [en]

    Stem wood powders were fired in a mullite-lined pilot-scale oxygen-blown pressurized entrained-flow gasifier. During repeated campaigns involving increases in fuel load and process temperature, slag formations that eventuated in the blockage of the gasifier outlet were observed. These slags were retrieved for visual and chemical characterization. It was found that the slags had very high contents of Al and, in particular, high Al/Si ratios that suggest likely dissolution of the mullite-based refractory of the gasifier lining due to interactions with the fuel ash. Possible causes for the slag formation and behavior are proposed, and practical implications for the design of future stem wood entrained-flow gasifiers are also discussed.

  • 9.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Comparison and validation of gas phase reaction schemes for black liquor gasification modeling2008In: AIChE Annual Meeting, Conference Proceedings, 2008Conference paper (Refereed)
  • 10.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Furusjö, Erik
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Black liquor gasification: CFD model predictions compared with measurements2010In: International Chemical Recovery Conference, 2010, Vol. 2, p. 160-171Conference paper (Refereed)
  • 11.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Furusjö, Erik
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Experiments and mathematical models of black liquor gasification: Influence of minor gas components on temperature, gas composition, and fixed carbon conversion2010In: TAPPI Journal, ISSN 0734-1415, Vol. 9, no 9, p. 15-24Article in journal (Refereed)
    Abstract [en]

    In this work, predictions from a reacting Computational Fluid Dynamics (CFD) model of a gasification reactor are compared to experimentally obtained data from an industrial pressurized black liquor gasification plant. The data consists of gas samples taken from the hot part of the gasification reactor using a water cooled sampling probe. During the considered experimental campaign, the oxygen-to-black liquor equivalence ratio (λ was varied in three increments, which resulted in a change in reactor temperature and gas composition. The presented numerical study consists of CFD and thermodynamic equilibrium calculations in the considered λ-range using boundary conditions obtained from the experimental campaign. Specifically, the influence of methane concentration on the gas composition is evaluated using both CFD and thermodynamic equilibrium. The results show that the main gas components (H 2, CO, CO2) can be predicted within a relative error of 5% using CFD if the modeled release of H2S and CH4 are specified a priori. In addition, the calculations also show that the methane concentration has large influence on the reactor outlet temperature and final carbon conversion.

  • 12.
    Carlsson, Per
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Grönberg, C.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pettersson, Esbjörn
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lidman, M.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Experimental investigation of an industrial scale black liquor gasifier: Part 1: The effect of a reactor operation parameters on product gas composition2010In: Fuel, Vol. 89, p. 4025-4034Article in journal (Refereed)
  • 13. Eriksson, D.
    et al.
    Weiland, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Hedman, Henry
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Stenberg, M.
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lestander, T.A.
    Bergsten, U.
    Ohman, M.
    Characterization of Scots pine stump-root biomass as feed-stock for gasification2012In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 104, p. 729-736Article in journal (Refereed)
    Abstract [en]

    The main objective was to explore the potential for gasifying Scots pine stump-root biomass (SRB). Washed thin roots, coarse roots, stump heartwood and stump sapwood were characterized (solid wood, milling and powder characteristics) before and during industrial processing. Non-slagging gasification of the SRB fuels and a reference stem wood was successful, and the gasification parameters (synthesis gas and bottom ash characteristics) were similar. However, the heartwood fuel had high levels of extractives (≈19%) compared to the other fuels (2-8%) and thereby ≈16% higher energy contents but caused disturbances during milling, storage, feeding and gasification. SRB fuels could be sorted automatically according to their extractives and moisture contents using near-infrared spectroscopy, and their amounts and quality in forests can be predicted using routinely collected stand data, biomass functions and drill core analyses. Thus, SRB gasification has great potential and the proposed characterizations exploit it. © 2011 Elsevier Ltd.

  • 14. Eriksson, G.
    et al.
    Hedman, Henry
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Backman, Rainier
    Ohman, M.
    Combustion characterization of rapeseed meal and possible combustion applications2009In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, no 8, p. 3990-3939Article in journal (Refereed)
    Abstract [en]

    A future shortage of biomass fuel can be foreseen. The production of rapeseed oil for a number of purposesis increasing, among others, for biodiesel production. A yproduct from the oil extraction process is rapeseed meal (RM), presently used as animal feed. Further increases in supply will make fuel use an option. Several energy companies have shown interest but have been cautious because of the scarcity of data on fuel properties, which led to the present study. Combustion-relevant properties of RM from several producers have been determined. The volatile fraction (74 ± .06%wt ds) is comparable to wood; the moisture content (6.2-11.8%wt) is low; and the ash content (7.41 ± 0.286%wt ds) is high compared to most other biomass fuels. The lower heating value is 18.2 ± 0.3 MJ/kg (dry basis). In comparison to other biomass fuels, the chlorine content is low (0.02-0.05%wt ds) and the sulfur content is high (0.67-0.74%wt ds). RM has high contents of nitrogen (5.0-6.4%wt ds), phosphorus (1.12-1.23%wt ds), and potassium (1.2-1.4%wt ds). Fuel-specific combustion properties of typical RM were determined through combustion tests, with an emphasis on gas emissions, ash formation, and potential ash-related operational problems. Softwood bark was chosen as a suitable and representative co-combustion (woody) fuel. RM was added to the bark at two levels: 10 and 30%wt ds. These mixtures were pelletized, and so was RM without bark (for durability mixed with cutter shavings, contributing 1%wt of the ash). Each of these fuels was combusted in a 5 kWfluidized bed and an underfed pellet burner (to simulate grate combustion). Pure RM was combusted in a powder burner. Emissions of NO and SO2 were high for all combustion tests, requiring applications with flue gas cleaning, economically viable only at large scale. Emissions of HCl were relatively low. Temperatures for initial bed agglomeration in the fluidized-bed tests were high for RM compared to many other agricultural fuels, thereby indicating that RM could be an attractive fuel from a bed agglomeration point of view. The results of grate combustion suggest that slagging is not likely to be severe for RM, pure or mixed with other fuels. Fine-mode particles from fluidized-bed combustion and grate combustion mainly contained sulfates of potassium, suggesting that the risk of problems caused by deposit formation should be moderate. The chlorine concentration of the particles was reduced when RM was added to bark, potentially lowering the risk of high-temperature corrosion. Particle emissions from powder combustion of RM were 17 times higher than for wood powder, and the fine-mode fraction contained mainly K-phosphates known to cause deposits, suggesting that powder combustion of RM should be used with caution. A possible use of RM is as a sulfur-containing additive to biomass fuels rich in Cl and K for avoiding ash-related operational problems in fluidized beds and grate combustors originated from high KCl concentrations in the flue gases © 2009 American Chemical Society.

  • 15. Gabra, M.
    et al.
    Ohman, M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Kjellstrom, B.
    Alkali retention/separation during bagasse gasification: A comparison between a fluidised bed and a cyclone gasifier2001In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 21, no 6, p. 461-476Article in journal (Refereed)
    Abstract [en]

    Biomass fuelled integrated gasification/gas turbines (BIG/GTs) have been found to be one of the most promising technologies to maximise electricity output in the sugar industry. However, biomass fuels contain alkali metals (Na and K) which may be released during the gasification processes and cause deleterious effects on the downstream hardware (e.g. the blades of gas turbines). Much research has therefore been focused on different kinds of gas cleaning. Most of these projects are using a fluidised bed gasifier and includes extensive gas cleaning which leads to a high capital investment. Increasing alkali retention/separation during the gasification may lead to improved producer gas quality and reduced costs for gas cleaning. However, very little quantitative information is available about the actual potential of this effect. In the present work, comparative bench-scale tests of bagasse gasification were therefore run in an isothermal fluidised bed gasifier and in a cyclone gasifier to evaluate which gasification process is most attractive as regards alkali retention/separation, and to try to elucidate the mechanisms responsible for the retention. The alkali retention in the fluidised bed gasifier was found to be in the range of 12-4% whereas in the cyclone gasifier the alkali separation was found to be about 70%. No significant coating of the fluidised bed's bed material particles could be observed. The SEM/EDS and the elemental maps of the bed material show that a non-sticky ash matrix consisting of mainly Si, Al and K were distributed in a solid form separated from the particles of bed material. This indicates the formation of a high temperature melting potassium containing silicate phase, which is continuously scavenged and lost from the bed through elutriation. © 2001 Elsevier Science Ltd. All rights reserved.

  • 16. Gabra, M.
    et al.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Backman, Rainier
    Kjellstrom, B.
    Evaluation of cyclone gasifier performance for gasification of sugar cane residue: Part 1: Gasification of bagasse2001In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 21, no 5, p. 351-369Article in journal (Refereed)
    Abstract [en]

    A method for avoiding excessive amount of alkali compounds and carryover particles in producer gas from gasification of sugar cane residue has been studied and evaluated. The cane sugar residue is gasified in a two-stage combustor at atmospheric pressure, where the first stage is a cyclone gasifier. The cyclone works as particle separator as well. This paper covers the results obtained for gasification of bagasse. Bagasse powder was injected into the cyclone with air and steam as transport medium. The gasification tests were made with two feeding rates, 39 and 52 kg/h. Seven experiments were conducted with the equivalence ratio being varied. The heating values of the producer gas are sufficient for stable gas turbine combustion. About 60-70% of the alkali input with fuel was separated from the producer gas in the cyclone. However the total alkali contents of the producer gas was found to be higher than in ABB Stal PFBC gas turbines and at least an order of magnitude higher than what is required by most gas turbine manufacturers for operation of a gas turbine. The carryover particles concentrations in the producer gas were found to be in the range of that for PFBC gas turbines, but higher than what is required by most gas turbine manufacturers for operation of a gas turbine. Samples studied with scanning electronic microscope give indication that most of the carryover particles are below 10 μm in size. Fly ash-melting tests have not shown any major ash melting up to 1200°C, but it was found that some of the particles entrained with producer gas were partially melted. Integrated experiments with a gas turbine need to be done for accurate evaluation of the possibilities to use the producer gas from the gasification of bagasse to run a gas turbine without problems of hard deposits and corrosion on the turbine blades. In part 2 of this two-part paper the results from cane trash gasification tests are reported. © 2001 Published by Elsevier Science Ltd.

  • 17. Gabra, M.
    et al.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Backman, Rainier
    Kjellstrom, B.
    Evaluation of cyclone gasifier performance for gasification of sugar cane residue: Part 2: Gasification of cane trash2001In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 21, no 5, p. 371-380Article in journal (Refereed)
    Abstract [en]

    In Part 1 of this two-part paper, results from gasification of bagasse in a cyclone gasifier have been reported. In this paper results from gasification of cane trash in the same cyclone gasifier are presented. The cane trash powder is injected into the cyclone with air as transport medium. The gasification tests were made with two feeding rates, 39 and 46 kg/h at two equivalence ratios of 0.25 and 0.20 and the gasification temperature ranging from 820°C to 850°C. It was found that the heating value of the producer gas is in the range of 4.5-4.8 MJ/Nm3(dry gas), which is sufficient for stable gas turbine combustion. Significant alkali separation has been achieved in the cyclone stage. However, the alkali levels and carryover particle concentrations in the producer gas were found to be higher than allowable in a gas turbine. Despite high ash melting temperatures found by the TGA-DTA, deposition problems cannot be excluded since some carryover panicles in the producer gas seem to have been melted and since some gasification of K and Na compounds is indicated. As an overall assessment, cane trash appears as a more problematic fuel than bagasse for this application. Integrated experiments with a gas turbine need to be done for accurate evaluation of the possibilities to use the producer gas from the gasification of cane trash to run a gas turbine without problems of hard deposits and corrosion on the turbine blades. © 2001 Published by Elsevier Science Ltd.

  • 18.
    Gebart, Bo Rikard
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Carlsson, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Grönberg, C.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Weiland, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Johansson, Ann-Christine
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Recent advances in the understanding of pressurized black liquor gasification.2011In: Cellulose Chemistry and Technology, Vol. 45, p. 521-526Article in journal (Refereed)
  • 19.
    Gebart, Rikard
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lidman, M.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Holmberg, H.
    Risberg, M.
    Vortex gasification of biomass for CHP and lime kiln fuel2011In: The International Conference on Thermochemical Conversion Science(tcbiomass), 2011Conference paper (Refereed)
  • 20.
    Gebart, Rikard
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Carlsson, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Grönberg, C.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pettersson, Esbjörn
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lidman, M.
    Influence from varying operating parameters on the syngas composition from a black liquor gasifier.2011In: The International Conference on Thermochemical Conversion Science(tcbiomass), 2011Conference paper (Refereed)
  • 21.
    Gebart, Rikard
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov G.W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pettersson, Esbjörn
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Risberg, M.
    Carlsson, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Turning a pulp mill into a biorefinery: A possible outcome from the 2nd black liquor gasification program2008In: 2008 Nordic Wood Biorefinery Conference, NWBC 2008 - Proceedings, 2008, p. 56-61Conference paper (Refereed)
  • 22. Gersen, S.
    et al.
    Van Essen, M.
    Visser, P.
    Ahmad, M.
    Mokhov, A.
    Sepman, Alexey
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Alberts, R.
    Duoma, A.
    Levinsky, H.
    Detection of H2S, So2 and NO2 in CO2 at pressures ranging from 1- 40 bar by using broadband absorption spectroscopy in the UV/VIS range2014In: Energy Procedia, 2014, Vol. 63, p. 2570-2582Conference paper (Refereed)
  • 23.
    Grönberg, C.
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, H.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhman, R.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Granberg, G.
    Jönsson, J.
    Trace elements in the syngas during pressurised black liquor gasification2009In: 10th International Conference on Energy for a Clean Environment, 2009Conference paper (Refereed)
  • 24. Gullberg, Marcus
    et al.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Spray characterization of twin fluid external mix atomization of pyrolysis oil.2012In: Atomization and Sprays, Vol. 22, p. 897-919Article in journal (Refereed)
  • 25. Göktepe, B.
    et al.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Leitao, N.
    Fernandez, E.
    Visualization of the reactive swirling flows in a 150 kW wood powder burner2010In: 7th International Conference on Heat Transfer, Fluid mechanics and Thermodynamics, 2010Conference paper (Refereed)
  • 26. Göktepe, B.
    et al.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Leitao, N.
    Leitao, I.V.
    Mericia, J.G.
    Fernandes, E.C.
    Simultaneous pressure and heat release measurements in a 150 kW wood powder burner2010In: SPEIC 10 - Towards sustainable Combustion, 2010Conference paper (Refereed)
  • 27.
    Göktepe, B.
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Saber, A. H.
    Gebart, R.
    Lundström, T. S.
    Cold flow experiments in an entrained flow gasification reactor with a swirl-stabilized pulverized biofuel burner2016In: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 85, p. 267-277Article in journal (Refereed)
    Abstract [en]

    Short particle residence time in entrained flow gasifiers demands the use of pulverized fuel particles to promote mass and heat transfer, resulting high fuel conversion rate. The pulverized biomass particles have a wide range of aspect ratios which can exhibit different dispersion behavior than that of spherical particles in hot product gas flows. This results in spatial and temporal variations in temperature distribution, the composition and the concentration of syngas and soot yield. One way to control the particle dispersion is to impart a swirling motion to the carrier gas phase. This paper investigates the dispersion behavior of biomass fuel particles in swirling flows. A two-phase particle image velocimetry technique was applied to simultaneously measure particle and gas phase velocities in turbulent isothermal flows. Post-processed PIV images showed that a poly-dispersed behavior of biomass particles with a range of particle size of 112–160 µm imposed a significant impact on the air flow pattern, causing air flow decelerated in a region of high particle concentration. Moreover, the velocity field, obtained from individually tracked biomass particles showed that the swirling motion of the carrier air flow gives arise a rapid spreading of the particles. © 2016 Elsevier Ltd

  • 28.
    Göktepe, B
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center. Energy Engineering, Division of Energy Science, Luleå University of Technology.
    Umeki, K
    Energy Engineering, Division of Energy Science, Luleå University of Technology.
    Gebart, R
    Energy Engineering, Division of Energy Science, Luleå University of Technology.
    Does distance among biomass particles affect soot formation in an entrained flow gasification process?2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 141, p. 99-105Article in journal (Refereed)
    Abstract [en]

    Soot creates technical challenges in entrained flow biomass gasification processes, e.g. clogging of flow passages, fouling on system components and reduced efficiency of gasification. This paper demonstrates a novel soot reduction method in a laboratory-scale entrained flow reactor by forced dispersion of biomass particles. Gasification of small biomass particles was done in a flat flame burner where a steady stream of biomass was sent. The flat flame burner was operated with a premixed sub-stoichiometric methane-air flame to simulate the conditions in an entrained flow gasifier. The dispersion of biomass particles was enhanced by varying the flow velocity ratio between particle carrier gas and the premixed flame. Primary soot particles evolved with the distance from the burner exit and the soot volume fraction was found to have a peak at a certain location. Enhanced particle separation diminished the peaks in the soot volume fraction by 35-56% depending on the particle feeding rates. The soot volume fraction was found to decrease towards an asymptotic value with increasing inter-particle distance. © 2015 Elsevier B.V. All rights reserved.

  • 29. Haggstrom, C.
    et al.
    Ohrman, O.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Rownaghi, A.A.
    Hedlund, J.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Catalytic methanol synthesis via black liquor gasification2012In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 94, no 1Article in journal (Refereed)
    Abstract [en]

    Biofuel production from gasified black liquor is an interesting route to decrease green house gas emissions. The only pressurised black liquor gasifier currently in pilot operation is located in Sweden. In this work, synthesis gas was taken online directly from this gasifier, purified from hydrocarbons and sulphur compounds and for the first time catalytically converted to methanol in a bench scale equipment. Methanol was successfully synthesised during 45 h in total and the space time yield of methanol produced at 25 bar pressure was 0.16-0.19 g methanol/(g catalyst h). The spent catalyst exposed to gas from the gasifier was slightly enriched in calcium and sodium at the inlet of the reactor and in boron and nickel at the outlet of the reactor. Calcium, sodium and boron likely stem from black liquor whereas nickel probably originates from the stainless steel in the equipment. A slight deactivation, reduced surface area and mesoporosity of the catalyst exposed to gas from the gasifier were observed but it was not possible to reveal the origin of the deactivation. In addition to water, the produced methanol contained traces of hydrocarbons up to C 4, ethanol and dimethyl ether. © 2011 Elsevier B.V. All rights reserved.

  • 30.
    Johansson, A.C.
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, H
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sandström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marklund, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, O.G.W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Narvesjö, J
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Characterization of pyrolysis products produced from different Nordic biomass types in a cyclone pilot plant2016In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 146, p. 9-19Article in journal (Refereed)
    Abstract [en]

    Summary: Pyrolysis is a promising thermochemical technology for converting biomass to energy, chemicals and/or fuels. The objective of the present paper was to characterize fast pyrolysis products and to study pyrolysis oil fractionation. The products were obtained from different Nordic forest and agricultural feedstocks in a pilot scale cyclone pyrolysis plant at three different reactor temperatures. The results show that the main elements (C, H and O) and chemical compositions of the products produced from stem wood, willow, forest residue and reed canary grass are in general terms rather similar, while the products obtained from bark differ to some extent. The oil produced from bark had a higher H/Ceff ratio and heating value which can be correlated to a higher amount of pyrolytic lignin and extractives when compared with oils produced from the other feedstocks. Regardless of the original feedstock, the composition of the different pyrolysis oil fractions (condensed and aerosol) differs significantly from each other. However this opens up the possibility to use specifically selected fractions in targeted applications. An increased reactor temperature generally results in a higher amount of water and water insoluble material, primarily as small lignin derived oligomers, in the produced oil. © 2016 Elsevier B.V. All rights reserved.

  • 31.
    Johansson, A.C.
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov G.W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pettersson, Esbjörn
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sweeney, D.
    Tar and trace element measurements in synthesis gas from a pressurized black liquor gasifier.2013In: Proceedings 21st European Biomass Conference and Exhibition, 2013Conference paper (Refereed)
  • 32. Jonsson, C.Y.C.
    et al.
    Stjernberg, J.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Lindblom, B.
    Bostrom, D.
    Ohman, M.
    Deposit formation in a grate-kiln plant for iron-ore pellet production.: Part 1: Characterization of process gas particles2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6159-6170Article in journal (Refereed)
    Abstract [en]

    Slag formation in the grate-kiln process is a major problem for iron-ore pellet producers. It is therefore important to understand the slag formation mechanism in the grate-kiln production plant. This study initiated the investigation by in situ sampling and identifying particles in the flue gas from a full-scale 40 MW grate-kiln production plant for iron-ore pelletizing. Particles were sampled from two cases of combustion with pulverized coal and heavy fuel oil. The sampling location was at the transfer chute that was situated between the traveling grate and the rotary kiln. The particle-sampling system was set up with a water-cooled particle probe equipped with nitrogen gas dilution, cyclone, and low-pressure impactor. Sub-micrometer and fine particles were size-segregated in the impactor, while coarse particles (>6 μm) were separated with a cyclone before the impactor. Characterization of these particles was carried out with environmental scanning electron microscopy (ESEM), and the morphology of sub-micrometer particles was studied with transmission electron microscopy (TEM). The results showed that particles in the flue gas consisted principally of fragments from iron-ore pellets and secondarily of ashes from pulverized coal and heavy fuel oil combustions. Three categories of particle modes were identified: (1) sub-micrometer mode, (2) first fragmentation mode, and (3) second fragmentation mode. The sub-micrometer mode consisted of vaporized and condensed species; relatively high concentrations of Na and K were observed for both combustion cases, with higher concentrations of Cl and S from heavy fuel oil combustion but higher concentrations of Si and Fe and minor P, Ca, and Al from coal combustion. The first fragmentation mode consisted of both iron-ore pellet fines and fly ash particles; a significant increment of Fe (>65 wt %) was observed, with higher concentrations of Ca and Si during heavy fuel oil combustion but higher concentrations of Si and Al during coal combustion. The second fragmentation mode consisted almost entirely of coarse iron-ore pellet fines, predominantly of Fe (∼90 wt %). The particles in the flue gas were dominantly iron-ore fines because the second fragmentation mode contributed >96 wt % of the total mass of collected particles. © 2013 American Chemical Society.

  • 33. Landälv, Ingvar
    et al.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Marke, Birgitta
    Granberg, Fredrik
    Furusjö, Erik
    Löwnertz, Patrik
    Öhrman, Olov G.W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sørensen, Esben Lauge
    Salomonsson, Per
    Two years experience of the BioDME project: A complete wood to wheel concept2014In: Environmental Progress and Sustainable Energy, 2014, Vol. 33, p. 744-750, article id 3Conference paper (Refereed)
    Abstract [en]

    Dimethyl ether (DME), is an excellent diesel fuel that can be produced through gasification from multiple feedstocks. One particularly interesting renewable feedstock is the energy rich by-product from the pulping process called black liquor (BL). The concept of utilizing BL as gasifier feed, converting it via syngas to DME and then compensating the withdrawal of BL energy from the pulp mill by supplying biomass to a conventional combined heat and power plant, is estimated to be one of the most efficient conversion concepts of biomass to a renewable fuel on a well-to-wheel basis. This concept has been demonstrated by the four-year BioDME project, including field tests of DME-fueled heavy-duty trucks that are operated commercially. Up till the summer of 2013 more than 500 tons of BioDME has been produced and distributed to 10 HD trucks, which in total has run more than 1 million km in commercial service. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 744–750, 2014

  • 34. Leijenhorst, E.J.
    et al.
    Assink, D.
    van den Beld, L.
    Weiland, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Carlsson, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Entrained flow gasification of straw and wood derived pyrolysis oil in a pressurized oxygen blow gasifier2015In: Biomass & Energy, Vol. 79, p. 166-76Article in journal (Refereed)
  • 35. Leijenhorst, E.J.
    et al.
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Pressurized entrained flow gasification of pyrolysis oil.2012In: PyNe Newsletter, ISSN 2040-2759, no 32Article in journal (Refereed)
  • 36. Lindstrom, E.
    et al.
    Sandstrom, M.
    Bostrom, D.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Ohman, M.
    Slagging characteristics during combustion of cereal grains rich in phosphorus2007In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 21, no 2, p. 710-717Article in journal (Refereed)
    Abstract [en]

    A residential cereal burner (20 kW) was used study the slagging characteristics of cereal grains with and without lime addition. The deposited bottom ash and slag were analyzed using X-ray diffraction (XRD), to identify the crystalline phases, and environmental scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (ESEM/EDS), to study the morphology and elemental composition. Phase-diagram information was utilized to extract qualitative information about the behavior of cereal grain ashes under combustion conditions. Chemical equilibrium model calculations were used to interpret the experimental results. In addition, investigations of the melting behavior of the produced slags were conducted. The results showed significant differences in slagging characteristics between the fuels that were used. The slags consisted of high-temperature melting crystalline phases (calcium/magnesium potassium phosphates) and a potassium-rich phosphate melt for all cereal grains. For oat and barley, cristobalite was also identified in the slag. Furthermore, in these cases, the slags most probably contained a potassium-rich silica melt. The differences in the melting behaviors of the slags had a considerable effect on the performance of the burner. The addition of lime reduced the formation of slag for barley and totally eliminated it for rye and wheat. This occurs because lime contributes to the formation of high-temperature melting calcium potassium phosphates. © 2007 American Chemical Society.

  • 37. Lundgren, J.,
    et al.
    Pettersson, E.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Combustion of horse manure for heat production2009In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 100, no 12, p. 3121-3126Article in journal (Refereed)
    Abstract [en]

    The main objectives of this paper have been to evaluate the use of horse manure and wood-shavings as a fuel for heat production and to provide sets of data on the chemical composition, ash characteristics and ash forming elements of the fuel. Another objective has been to investigate the possibility to use the ash as fertiliser by analysing the heavy metal and nutrient contents. The results showed that the fuel is well suited for combustion for heat production causing low emissions of products of incomplete combustion. The emissions of NOx were however high due to the high content of fuel bound nitrogen. Emissions of CO and NOx were typically in the range of 30-150 mg/Nm3 and 280-350 mg/Nm3 at 10 vol% O2, respectively. The analysis of the ash showed on sufficiently low concentration of heavy metals to allow recycling. © 2009 Elsevier Ltd. All rights reserved.

  • 38. Lycksam, H.
    et al.
    Sjodahl, M.
    Gren, P.
    Ohman, M.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    High-speed interferometric measurement and visualization of the conversion of a black liquor droplet during laser heating2012In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 50, no 11, p. 1654-1661Article in journal (Refereed)
    Abstract [en]

    Black liquor is a mix of organic and inorganic materials that is left after the kraft pulping process. In a modern pulp mill the pulping chemicals and the energy in the black liquor is recovered and used in the pulping cycle by burning the black liquor in a recovery burner. An alternative to the recovery boiler is to gasify the black liquor to produce an energy rich synthesis gas that can be upgraded into synthetic fuels or chemicals. Characterization of black liquor has mostly been done under conditions that are relevant for recovery boilers but the conditions in a gasifier differ significantly from this. In particular the droplets are much smaller and the heating rates are much higher. This paper presents an optical interferometric technique that has the potential to produce data under relevant conditions for gasification. In the paper, results are measured at atmospheric conditions and with relatively low heating rate. However, the method can be applied also for pressurized conditions and at heating rates that are only limited by the frame rate of the digital camera that is used to capture the transient event when the droplets are heated. In the paper the dynamic properties of the gas ejected from and the swelling during conversion of a single droplet are measured. © 2012 Elsevier Ltd.

  • 39. Ma, C.
    et al.
    Weiland, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Hedman, Henry
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Bostrom, D.
    Backman, Rainier
    Ohman, M.
    Characterization of reactor ash deposits from pilot-scale pressurized entrained-flow gasification of woody biomass2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 11, p. 6801-6814Article in journal (Refereed)
    Abstract [en]

    Pressurized entrained-flow gasification of renewable forest residues has the potential to produce high-quality syngas suitable for the synthesis of transport fuels and chemicals. The ash transformation behavior during gasification is critical to the overall production process and necessitates a level of understanding to implement appropriate control measures. Toward this end, ash deposits were collected from inside the reactor of a pilot-scale O 2-blown pressurized entrained-flow gasifier firing stem wood, bark, and pulp mill debarking residue (PMDR) in separate campaigns. These deposits were characterized with environmental scanning electron microscopy equipped with energy-dispersive X-ray spectrometry and X-ray diffractometry. The stem wood deposit contained high levels of calcium and was comparatively insubstantial. The bark and PMDR fuels contained contaminant sand and feldspar particles that were subsequently evident in each respective deposit. The bark deposit consisted of lightly sintered ash aggregates comprising presumably a silicate melt that enveloped particles of quartz and, to a lesser degree, feldspars. Discontinuous layers likely to be composed of alkaline-earth metal silicates were found upon the aggregate peripheries. The PMDR deposit consisted of a continuous slag that contained quartz and feldspar particles dispersed within a silicate melt. Significant levels of alkaline-earth and alkali metals constituted the silicate melts of both the bark and PMDR deposits. Overall, the results suggest that fuel contaminants (i.e., quartz and feldspars) play a significant role in the slag formation process during pressurized entrained-flow gasification of these woody biomasses. © 2013 American Chemical Society.

  • 40.
    Marklund, Magnus
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Characterisation of a spray burner nozzle for black liquor gasification2004In: 2004 International Chemical Recovery Conference, 2004, Vol. 2, p. 741-745Conference paper (Refereed)
  • 41.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Carlsson, Per
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Entrained flow black liquor gasification: Considerations for improvement of CFD reactor model predictions2011In: Proceedings Flame Days 2011, 2011Conference paper (Refereed)
  • 42.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Engstrom, F.
    Water spray characterization of a coaxial air-assisted swirling atomizer at sonic conditions2010In: Atomization and sprays, ISSN 1044-5110, E-ISSN 1936-2684, Vol. 20, no 11, p. 955-963Article in journal (Refereed)
    Abstract [en]

    The present work was performed to quantitatively investigate the spray characteristics from a swirling coaxial gasassisted atomizer for moderate industrial flow rates of water, low to medium swirl generation of the assisting air, and high momentum flux ratios at sonic air flow rates at the convergent nozzle exit. In the considered cases, two different liquid to gas mass flow ratios for two different nozzle contraction ratios were studied, with and without the use of swirl. The spray characteristics were obtained by using phase Doppler anemometry and a three-coordinate traversing system, which could accurately position the measurement volume in the spray. For the conditions considered in this paper, it was found that the introduced swirl reduces the axial velocity in the center core of the spray up to 45%. Furthermore, the spreading rate of the resulting spray jet increased when the swirl increased, and the liquid to gas mass flow ratio and the momentum flux ratio were decreased. The largest droplets were found in the center of the spray, and the smallest droplets appeared around the middle radial position of measurement. © 2010 by Begell House, Inc.

  • 43.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Fletcher, D.F.
    Determination of the influence of uncertain model parameters in pressurized gasification of black liquor using a factorial design2005In: Combustion Science and Technology, ISSN 0010-2202, E-ISSN 1563-521X, Vol. 177, no 3, p. 435-453Article in journal (Refereed)
    Abstract [en]

    Introduction of pressurized gasification of black liquor in the pulping industry has the potential to give a significant increase in energy efficiency. However, uncertainties about the reliability and robustness of the technology are preventing large-scale market introduction. One important step toward a greater trust in the process reliability is the development of a better understanding of the sensitivity of the process to parameter variations. A computational fluid dynamics model for pressurized gasification of black liquor in an entrained-flow gasifier is presented and used for investigation of the effects of uncertainties in the specific heat capacity of black liquor, the radiation absorption coefficient, and the volatile devolatilization rate using factorial design methodology. It is found that all main factor effects, but none of the interaction effects, influence the considered responses: char conversion, maximum temperature, and outlet temperature. However, the main effects are found to be relatively small and the uncertainties in the examined model parameters would not invalidate the results from a design optimization with the presented model. Copyright © Taylor & Francis Inc.

  • 44.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Tegman, R.
    Comparisons of initial experiments and reactor model predictions in high temperature black liquor gasification2009In: Tappi Journal, Vol. 8, no 2Article in journal (Refereed)
    Abstract [en]

    Pressurized high temperature black liquor gasification might significantly improve the efficiency of the energy and chemical recovery cycle in kraft pulping. The process, which is based on the entrained-flow principle, is under development, and a scale-up from an existing pilot gasifier is planned. We developed a self-consistent computational fluid dynamic (CFD) model, in conjunction with pilot gasifier experiments, as a tool for scale-up. This report compares model predictions against experimental pilot gasifier data. The agreement between model and experiments is encouraging in certain areas, but significant discrepancies resulted for other areas. Model predictions of global performance parameters, such as sulfate reduction efficiency and carbon conversion, are in reasonable agreement with the experiments, but the predicted gas composition differed significantly from results of the experiments. Direct measurements of quantities to validate the current model validation are difficult to obtain because of severe conditions in the gasifier, and many of the model comparisons are based on indirect values. Hence, it is difficult to judge whether the errors come from the experiment or the simulation. Before we can draw a definite conclusion about the model's validity, improved in-situ measurements inside the gasifier are necessary and are currently under development. Successful development of a computational fluid dynamic model will further the development of black liquor gasification, leading to improved efficiency of the energy and chemical recovery cycle in kraft pulping.

  • 45.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Whitty, K.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Approximate Modelling of the Flow of Gas and Droplets in an Entrained Flow Pressurised Black Liquor Gasification Reactor2001In: Proceedings of the International Joint Power Generation Conference, 2001, Vol. 1, p. 385-393Conference paper (Refereed)
  • 46.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Tegman, R.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    A self-consisted CFD-model for pressurized high temperature black liquor gasification2008In: IFRF Combustion Journal, ISSN 1562-479X, p. 1-34Article in journal (Refereed)
    Abstract [en]

    High temperature pressurised black liquor gasification has the potential to significantly improve the efficiency of energy and chemical recovery in the pulping industry. However, a lack of demonstration of the reliability of the process has delayed its large scale industrial implementation. As an important step towards a greater trust in the process reliability, a self-consistent CFD model has been developed. This paper contains a detailed description of the model and a performance prediction of an entrained flow pilot gasifier for a typical operational condition. Emphasis is put on the modelling of input data for the CFD simulation where eight key assumptions form the basis for a consistent model of the black liquor composition. The results for the pilot gasifier performance with typical values for the design variables indicate that the droplet size should be

  • 47.
    Marklund, Magnus
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Tegman, R.
    Gebart, Rikard
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    CFD modelling of black liquor gasification: Identification of important model parameters2007In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 86, no 42351, p. 1918-1926Article in journal (Refereed)
    Abstract [en]

    Pressurized high temperature black liquor gasification has the potential to significantly improve the efficiency of energy and chemical recovery in the pulping industry and to enable new processes, e.g. production of renewable automotive fuels from the formed synthesis gas. However, the current process is still considered as novel and the interest in validated computer models for scale-up and process optimisation is large. In this paper a sensitivity analysis on the four most important model parameters in the pre-processing 'droplet composition model' for a proposed CFD model has been performed. It was shown that careful measurements of the amount of sulphur released to the gas phase as H2S during devolatilization and the concentration ratio of Na2S and Na2SO4 in the black liquor char under real process conditions are of great importance for calibration of the model. © 2007 Elsevier Ltd. All rights reserved.

  • 48.
    Molinder, R.
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Sandström, L.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, H.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Characteristics of Particles in Pyrolysis Oil2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 11, p. 9456-9462Article in journal (Refereed)
    Abstract [en]

    Particles filtered out of pyrolysis oil produced through fast pyrolysis of stem wood, willow, reed canary grass, bark, and forest residue were characterized using scanning electron microscopy and energy-dispersive spectroscopy with the aim of identifying particle categories and discussing transport mechanisms of particles and inorganics into the oil. Particles filtered out of both the condensed and the aerosol fractions of the oil displayed three types of morphology: (i) char-like structures (1-15 μm), (ii) spheres (100 nm to 1 μm), and (iii) irregularly shaped residue (50-500 nm). The char-like structures were identified as char. The spheres and irregularly shaped residue shared morphology and composition with tar balls and organic particles with inorganic inclusions. These particles could have formed either during the fast pyrolysis stage or through precipitation from the oil during storage. All particles consisted mainly of C and O but also small amounts of inorganics. The particles from the aerosol fraction of the oil had higher inorganics content than the particles from the condensed fraction. The results were discussed, and suggested transport mechanisms of inorganics into particles were presented. © 2016 American Chemical Society.

  • 49.
    Molinder, Roger
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Wiinikka, Henrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Feeding small biomass particles at low rates2014In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 269, p. 240-246Article in journal (Refereed)
    Abstract [en]

    Biomass particles (75-1000μm) were fed at 9.0-66.5mgmin-1 (2.9-21.7W) using a particle feeder that dispensed particles by gravity through an injection tube. Feed rate was controlled by altering the velocity of a pusher block. Particles were agitated using a vibration motor and fed onto a balance and mass readings were continuously logged. Factors impacting reproducibility and feed rate stability were investigated as well as the effects of particle size and of pusher block velocity. Statistical analysis was applied to investigate patterns in particle feed rate data. Particle aggregation was identified as a factor which influenced feed rate stability and thereby also influencing reproducibility. Feed rate correlated well with pusher block velocity (R2=0.99). Statistical analysis showed strong indications (P values <0.01) of two patterns (clustering and trends) in the feed rate data which were attributed to changes in particle bed appearance with time. With all else being equal, particle size affected feed rate but not feed rate stability. A higher vibration amplitude was needed to agitate smaller particles. It was concluded that particle agitation control is a key to stable feeding of small biomass particles at low rates.

  • 50.
    Molinder, Roger
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Öhrman, Olov .G.W
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Energy Technology Center.
    Characterization and cleanup of wastewater from pressurized entrained flow biomass gasification2014In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 2, no 8, p. 2063-2069Article in journal (Refereed)
    Abstract [en]

    Wastewater produced during pressurized entrained flow biomass gasification (PEBG) was characterized and cleaned in order to raise the technology readiness level of the PEBG concept. Scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) were used to study material found in the water. The material was removed using filtration and the concentration of dissolved organic carbon (DOC), polyaromatic hydrocarbons (PAHs) and metals in filtered water was studied using standardized methods. Water was sampled during operation at three oxygen equivalence ratios (λ) and the results were compared to concentrations of gaseous hydrocarbons in the syngas. As λ increased, the amount of soot in the wastewater and the amount of soot precursors in the syngas was reduced. As a result the concentration of particles in the water was reduced and their composition shifted toward a higher percentage of inorganics (ash). PAH concentration trends in the water and in the syngas correlated and dissolved organic material in the water was reduced with increased λ. A particle removal efficiency of 98-99% was achieved using sedimentation and filtration while the DOC was reduced from ≈2.5 mg L-1 to below detection limit using granular activated carbon (GAC). © 2014 American Chemical Society.

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