Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 79) Show all publications
Hadi Jafari, P., Wingren, A., Hellström, J. G. & Gebart, R. (2020). Effect of process parameters on the performance of an air-blown entrained flow cyclone gasifier. International Journal of Sustainable Energy, 39(1), 21-40
Open this publication in new window or tab >>Effect of process parameters on the performance of an air-blown entrained flow cyclone gasifier
2020 (English)In: International Journal of Sustainable Energy, ISSN 1478-6451, E-ISSN 1478-646X, Vol. 39, no 1, p. 21-40Article in journal (Refereed) Published
Abstract [en]

Entrained flow gasification of biomass in a cyclone reactor combined by a gas engine has been applied in Nordic countries as one of the preferred methods for generating combined heat and power in small scales. The purpose of the current study was to optimise the gasification plant efficiency and understanding the influence of operating conditions. The experiments were carried out in a 2.4 MW(th) commercial gasification power plant. The gasifier was operated in optimum at a rather low lambda around 0.27 and a temperature of 950°C. The lower heating value of the clean product gas at this lambda was 5.95 MJ/Nm3. The experimental results also were compared with the predicted values from thermodynamic equilibrium calculations by Factsage 7.0. The performance of five different types of biofuels including torrefied spruce, peat, rice husk, bark and stemwood were assessed and compared with each other using thermodynamic equilibrium and available experimental data.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
Keywords
Cyclone gasification, Airblown, Biomass, Cold gas efficiency, Process performance
National Category
Fluid Mechanics and Acoustics Energy Engineering
Research subject
Fluid Mechanics; Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-74459 (URN)10.1080/14786451.2019.1626858 (DOI)
Funder
Bio4Energy, 191503
Note

Validerad;2020;Nivå 2;2020-01-27 (johcin)

Available from: 2019-06-13 Created: 2019-06-13 Last updated: 2020-01-27Bibliographically approved
Hadi Jafari, P., Risberg, M., Hellström, J. G. & Gebart, R. (2020). Numerical Simulation of Biomass Gasification in an Entrained Flow Cyclone Gasifier. Energy & Fuels
Open this publication in new window or tab >>Numerical Simulation of Biomass Gasification in an Entrained Flow Cyclone Gasifier
2020 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029Article in journal (Refereed) Epub ahead of print
Abstract [en]

A transient, two-way coupled Eulerian−Lagrangian computational fluid dynamics model has been developed for numerically investigating the gasification process of wood powder inside a cyclone-shaped reactor. The suggested model has considered heat and mass transfer, drying, devolatilization, and homogeneous and heterogeneous reactions. The model is validated using the experimental data from a commercial entrained-flow cyclone gasifier. The changes in gas composition as a function of equivalence ratio and the behavior of gasification process agreed well with the experimental measurement. Trajectories of individual particles were captured, and the behavior, mass fraction, and temperature distribution of several representative particles in different sizes were studied. Moreover, the model was successful in prediction of produced gas lower heating value, cold gas efficiency, and carbon conversion.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2020
National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-77487 (URN)10.1021/acs.energyfuels.9b03942 (DOI)
Funder
Bio4Energy, 191503
Available from: 2020-01-23 Created: 2020-01-23 Last updated: 2020-02-18
Jafri, Y., Furusjö, E., Kirtania, K., Gebart, R. & Granberg, F. (2018). A study of black liquor and pyrolysis oil co-gasification in pilot scale. Biomass Conversion and Biorefinery, 8(1), 113-124
Open this publication in new window or tab >>A study of black liquor and pyrolysis oil co-gasification in pilot scale
Show others...
2018 (English)In: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 8, no 1, p. 113-124Article in journal (Refereed) Published
Abstract [en]

The effect of the blend ratio and reactor temperature on the gasification characteristics of pyrolysis oil (PO) and black liquor (BL) blends with up to 20 wt% PO was studied in a pilot-scale entrained-flow gasifier. In addition to unblended BL, three blends with PO/BL ratios of 10/90, 15/85, and 20/80 wt% were gasified at a constant load of 2.75 MWth. The 15/85 PO/BL blend was used to investigate the effect of temperature in the range 1000–1100 °C. The decrease in fuel inorganic content with increasing PO fraction resulted in more dilute green liquor (GL), and a greater portion of the feedstock carbon ended up in syngas as CO. As a consequence, the cold gas efficiency increased by about 5%-units. Carbon conversion was in the range 98.8–99.5% and did not vary systematically with either fuel composition or temperature. Although the measured reactor temperatures increased slightly with increasing PO fraction, both unblended BL and the 15% PO blend exhibited largely similar behavior in response to temperature variations. The results from this study show that blending BL with the more energy-rich PO can increase the cold gas efficiency and improve the process carbon distribution without adversely affecting either carbon conversion or the general process performance.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-61518 (URN)10.1007/s13399-016-0235-5 (DOI)000425594800011 ()2-s2.0-85042226433 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-02-20 (rokbeg)

Available from: 2017-01-18 Created: 2017-01-18 Last updated: 2019-08-30Bibliographically approved
Hadi Jafari, P., Misiulia, D., Hellström, J. G. & Gebart, R. (2018). Modeling of Particle-Laden Cold Flow in a Cyclone Gasifier. Journal of Fluids Engineering - Trancactions of The ASME, 141(2), Article ID 021302.
Open this publication in new window or tab >>Modeling of Particle-Laden Cold Flow in a Cyclone Gasifier
2018 (English)In: Journal of Fluids Engineering - Trancactions of The ASME, ISSN 0098-2202, E-ISSN 1528-901X, Vol. 141, no 2, article id 021302Article in journal (Refereed) Published
Abstract [en]

Isothermal transient Eulerian–Lagrangian simulation of the turbulent gas–solid flow in a cyclone gasifier with two inlet tubes at 890 °C has been performed. The single-phase gas flow is modeled using SSG Reynolds stress turbulence model. Ten thousand representative solid particles of different sizes are injected from each inlet continuously at every second of simulation time. Particles are finally stopped as soon as they arrive at the outlet or reach the bottom plate of the gasifier. The effect of particle-to-gas coupling on the pressure and velocity of the flow and particles motion inside the gasifier is studied. The numerical approach can reasonably predict the impact of particle load on the gas flow as presented in the experimental results. Single particles are traveled throughout the transient gas flow field by using Lagrangian approach. High temperature of the gas flow inside the gasifier has significant effects on the swirl intensity reduction, damping the turbulence in the core region, pressure, and particle behaviors. However, the presence of solid particles does not have a notable influence on the swirl intensity and turbulence.

Place, publisher, year, edition, pages
The American Society of Mechanical Engineers (ASME), 2018
National Category
Engineering and Technology Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-70480 (URN)10.1115/1.4040929 (DOI)000452773200012 ()2-s2.0-85052003087 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-31 (svasva)

Available from: 2018-08-17 Created: 2018-08-17 Last updated: 2020-01-23Bibliographically approved
Göktepe, B., Umeki, K., Hazim, A., Lundström, S. & Gebart, R. (2017). Soot reduction in an entrained flow gasifier of biomass by active dispersion of fuel particles. Paper presented at 1st International Workshop on Oxy-Fuel Combustion, Montabaur, Germany, 10-11 February 2016. Fuel, 201, 111-117
Open this publication in new window or tab >>Soot reduction in an entrained flow gasifier of biomass by active dispersion of fuel particles
Show others...
2017 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 201, p. 111-117Article in journal (Refereed) Published
Abstract [en]

Soot is an undesired by-product of entrained flow biomass gasification since it has a detrimental effect on operation of the gasifier, e.g. clogging of flow passages and system components and reduction of efficiency. This study investigated how active flow manipulation by adding synthetic jet (i.e. oscillating flow through orifice) in feeding line affects dispersion of fuel particles and soot formation. Pine sawdust was gasified at the conditions similar to pulverized burner flame, where a flat flame of methane-air sub-stoichiometric mixture supported ignition of fuel particles. A synthetic jet flow was supplied by an actuator assembly and was directed perpendicular to a vertical tube leading to the center of the flat flame burner through which pine sawdust with a size range of 63–112 μm were fed into a reactor. Quartz filter sampling and the laser extinction methods were employed to measure total soot yield and soot volume fraction, respectively. The synthetic jet actuator modulated the dispersion of the pine sawdust and broke up particle aggregates in both hot and cold gas flows through generation of large scale vortex structures in the flow. The soot yield significantly reduced from 1.52 wt.% to 0.3 wt.% when synthetic jet actuator was applied. The results indicated that the current method suppressed inception of young soot particles. The method has high potential because soot can be reduced without changing major operation parameters.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-59714 (URN)10.1016/j.fuel.2016.09.039 (DOI)000402943900012 ()2-s2.0-84994765423 (Scopus ID)
Conference
1st International Workshop on Oxy-Fuel Combustion, Montabaur, Germany, 10-11 February 2016
Note

2017-06-02 (andbra);Konferensartikel i tidskrift

Available from: 2016-10-13 Created: 2016-10-13 Last updated: 2018-07-10Bibliographically approved
Hadi Jafari, P., Hellström, G. & Gebart, R. (2017). Turbulence Modelling of a Single-Phase Flow Cyclone Gasifier. Engineering, 9(9), 779-799, Article ID 79329.
Open this publication in new window or tab >>Turbulence Modelling of a Single-Phase Flow Cyclone Gasifier
2017 (English)In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 9, no 9, p. 779-799, article id 79329Article in journal, Editorial material (Refereed) Published
Abstract [en]

The current work aims to make a foundation for an engineering design of a cyclone gasifier to be able not only to predict its flow field with a suitable accuracy but also to investigate a large number of design alternatives with limited computer resources. A good single-phase flow model that can form the basis in an Euler-Lagrange model for multi-phase flow is also necessary for modelling the reacting flow inside a cyclone gasifier. The present paper provides an objective comparison between several popular turbulence modelling options including standard k-ε and SST with curvature corrections, SSG-RSM and LES Smagorinsky models, for the single-phase flow inside cyclone separators/gasifiers that can serve as a guide for further work on the reacting multi-phase flow inside cyclone gasifiers and similar devices. A detailed comparison between the models and experimental data for the mean velocity and fluctuating parts of the velocity profiles are presented. Furthermore, the capabilities of the turbulence models to capture the physical phenomena present in a cyclone gasifier that affects the design process are investigated.

Place, publisher, year, edition, pages
Scientific Research Publishing, 2017
Keywords
Cyclone Gasifier, Turbulence Modelling, Swirling Flow Pattern, Secondary Flow
National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-66442 (URN)10.4236/eng.2017.99047 (DOI)
Note

Validerad;2017;Nivå 1;2017-11-10 (andbra)

Available from: 2017-11-07 Created: 2017-11-07 Last updated: 2020-01-23Bibliographically approved
Hazim, A., Göktepe, B., Umeki, K., Lundström, S. & Gebart, R. (2016). Active fuel particles dispersion by synthetic jet in an entrained flow gasifier of biomass: Cold flow. Powder Technology, 302, 275-282
Open this publication in new window or tab >>Active fuel particles dispersion by synthetic jet in an entrained flow gasifier of biomass: Cold flow
Show others...
2016 (English)In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 302, p. 275-282Article in journal (Refereed) Published
Abstract [en]

Pulverized fuel (PF) burners play a key role for the performance of PF fired gasification and combustion plants, by minimizing pollutant emission, fuel consumption and hence fuel costs. However, fuel diversity in power generation plants imposes limitations on the performance of existing PF burners, especially when burning solid fuel particles with poor flowability like biomass sawdust. In the present study, a vertically downward laminar flow was laden with biomass particles at different particle mass loading ratios, ranging from 0.47 to 2.67. The particle laden flow was forced by a synthetic jet actuator over a range of forcing amplitudes, 0.35–1.1 kPa. Pulverized pine particles with a sieve size range of 63–112 μm were used as biomass feedstock. Two-phase particle image velocimetry was applied to measure the velocity of the particles and air flow at the same time. The results showed that the synthetic jet had a large influence on the flow fields of both air and powdered pine particles, via a convective effect induced by vortex rings that propagate in the flow direction. The particle velocity, particle dispersion and hence inter-particle distance increased with increasing forcing amplitude. Moreover, particles accumulated within a specific region of the flow, based on their size. The effect on particle dispersion was more pronounced in the forced flows with low mass loading ratios

National Category
Energy Engineering Fluid Mechanics and Acoustics
Research subject
Energy Engineering; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-59675 (URN)10.1016/j.powtec.2016.08.071 (DOI)000386420500027 ()2-s2.0-84984837775 (Scopus ID)
Note

Validerad; 2016; Nivå 1; 2016-10-11 (andbra)

Available from: 2016-10-12 Created: 2016-10-12 Last updated: 2018-07-10Bibliographically approved
Göktepe, B., Hazim, A., Gebart, R. & Lundström, S. (2016). Cold flow experiments in an entrained flow gasification reactor with a swirl-stabilized pulverized biofuel burner (ed.). International Journal of Multiphase Flow, 85, 267-277
Open this publication in new window or tab >>Cold flow experiments in an entrained flow gasification reactor with a swirl-stabilized pulverized biofuel burner
2016 (English)In: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 85, p. 267-277Article in journal (Refereed) Published
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

National Category
Fluid Mechanics and Acoustics Energy Engineering
Research subject
Fluid Mechanics; Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-12400 (URN)10.1016/j.ijmultiphaseflow.2016.06.016 (DOI)000381951000027 ()2-s2.0-84978033454 (Scopus ID)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (Local ID)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (Archive number)b8a0c0d3-9152-495a-bb2b-c4c628816eaf (OAI)
Note

Validerad; 2016; Nivå 2; 20160623 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Göktepe, B., Umeki, K. & Gebart, R. (2016). Does distance among biomass particles affect soot formation in an entrained flow gasification process? (ed.). Paper presented at . Fuel processing technology, 141(1), 99-105
Open this publication in new window or tab >>Does distance among biomass particles affect soot formation in an entrained flow gasification process?
2016 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 141, no 1, p. 99-105Article in journal (Refereed) Published
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.

National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-5352 (URN)10.1016/j.fuproc.2015.06.038 (DOI)000366779200014 ()2-s2.0-84948386130 (Scopus ID)370577d2-52d2-4c7e-8a05-38ca74f1e0a4 (Local ID)370577d2-52d2-4c7e-8a05-38ca74f1e0a4 (Archive number)370577d2-52d2-4c7e-8a05-38ca74f1e0a4 (OAI)
Note
Validerad; 2015; Nivå 2; 20150715 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Jafri, Y., Furusjö, E., Kirtania, K. & Gebart, R. (2016). Performance of a Pilot-Scale Entrained-Flow Black Liquor Gasifier (ed.). Paper presented at . Energy & Fuels, 30(4), 3175-3185
Open this publication in new window or tab >>Performance of a Pilot-Scale Entrained-Flow Black Liquor Gasifier
2016 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 4, p. 3175-3185Article in journal (Refereed) Published
Abstract [en]

Pilot-scale entrained flow gasification experiments were carried out at the 3 MWth LTU Green Fuels black liquor gasification (BLG) plant, using ∼140 tons of Kraft black liquor (BL) with a dry solids content of ∼72.5%. Comprehensive mass and energy balances were performed to quantify process performance under varying pressure, load, and oxygen/fuel ratio. Carbon conversion efficiency of the BLG process was 98.3%–99.2% and did not vary systematically in response to process changes. The unconverted carbon is almost exclusively present as dissolved organic carbon in the green liquor (GL) stream. GL is an aqueous solution of sodium carbonate and sodium sulfide used to recover the inorganic pulping chemicals present in BL for reuse in the pulp mill. A small fraction of syngas CO is converted to formate ions dissolved in GL through reaction with hydroxide ions. Unconverted carbon present in GL solids is insignificant. Syngas produced is subsequently upgraded to methanol and dimethyl ether (DME) in an integrated fuel synthesis facility. Concentration of H2 in syngas is not significantly affected by operating point changes in the domain investigated, while CO and CO2 concentrations are. Syngas hydrocarbon concentration values are typically in the single-digit parts per million (ppm) with the exception of C6H6, which was present at 16–127 ppm. CH4 is present at 0.5%–1.2%, with lower concentrations at higher temperatures, and shows good correlation with C6H6. A quantity of 24%–27% of BL sulfur ended up in the syngas as 1.5%–1.7% H2S and 64–72 ppm COS. Cold gas efficiencies (CGEs) on a lower heating value (LHV) basis, when including syngas CH4, were 52%–55% and decreased at higher temperature. CGEs on an LHV basis, when considering only H2 and CO with a sulfur-free BL heating value relevant for catalytic syngas upgrading, were 58%–60% and showed the opposite temperature dependence. Good mass and energy balance closures show the figures presented to be reliable. The results obtained from this study demonstrate process stability at varying operating conditions and can be further used for techno-economic analysis and design purposes.

National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-6993 (URN)10.1021/acs.energyfuels.6b00349 (DOI)000374804400069 ()2-s2.0-84966351790 (Scopus ID)55470d2e-94b0-4bc5-af0e-20f0365821b0 (Local ID)55470d2e-94b0-4bc5-af0e-20f0365821b0 (Archive number)55470d2e-94b0-4bc5-af0e-20f0365821b0 (OAI)
Note
Validerad; 2016; Nivå 2; 20160404 (yawjaf)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2019-08-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6958-5508

Search in DiVA

Show all publications