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Mesfun, S., Lundgren, J., Toffolo, A., Lindbergh, G., Lagergren, C. & Engvall, K. (2019). Integration of an electrolysis unit for producer gas conditioning in a bio-synthetic natural gas plant. Journal of energy resources technology, 141(1), Article ID 012002.
Open this publication in new window or tab >>Integration of an electrolysis unit for producer gas conditioning in a bio-synthetic natural gas plant
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2019 (English)In: Journal of energy resources technology, ISSN 0195-0738, E-ISSN 1528-8994, Vol. 141, no 1, article id 012002Article in journal (Refereed) Published
Abstract [en]

Producer gas from biomass gasification contains impurities like tars, particles, alkali salts, and sulfur/nitrogen compounds. As a result, a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into synthetic natural gas (SNG). A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of syngas produced. Internal rate of return (IRR) is evaluated as an economic indicator of the processes considered. Results indicate that, depending on process configuration, the production of SNG can be boosted by approximately 50-60% without the need of an additional carbon source, i.e., for the same biomass input as in standalone operation of the GoBi-Gas plant.

Place, publisher, year, edition, pages
ASME Press, 2019
Keywords
Electrolysis, Molten-carbonate, Process integration, Renewable electricity, SNG, Techno-economics, Biomass, Earnings, Gas plants, Gasification, Natural gasoline plants, Sulfur compounds, Synthesis gas, Internal rate of return, Molten carbonate, Operational parameters, Pressure and temperature, Synthetic natural gas, Natural gas conditioning
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-236341 (URN)10.1115/1.4040942 (DOI)2-s2.0-85052065806 (Scopus ID)
Funder
Swedish InstituteThe Kempe Foundations
Note

QC 20181109

Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2018-11-09Bibliographically approved
Montecchio, F., Bäbler, M. & Engvall, K. (2018). Development of an irradiation and kinetic model for UV processes in volatile organic compounds abatement applications. Chemical Engineering Journal, 348, 569-582
Open this publication in new window or tab >>Development of an irradiation and kinetic model for UV processes in volatile organic compounds abatement applications
2018 (English)In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 348, p. 569-582Article in journal (Refereed) Published
Abstract [en]

Air pollution from volatile organic compounds (VOCs) is one of the most important environmental hazards. Advanced oxidation processes (AOPs) with UV systems have been showing high potential for the abatement of VOCs. This work is aimed at modeling UV reactors for scaling-up AOPs from lab-scale to full-scale. The proposed model has a novel approach coupling the UV fluence rate to the photo-kinetic mechanism, for a robust understanding of the phenomena involved. The results show that the 185 nm wavelength is deeply absorbed within few centimeters by oxygen, while the 254 nm wavelength is weakly absorbed by the ozone generated in the reactor. Based on the fluence rate calculations, the reactions of ozone generation and depletion were modeled. The ozone net concentration was compared to the experimental results, for model verification. The model accurately predicts the effect of the airflow rate and reactor diameter for the tested cases. The acetaldehyde oxidation reaction was modeled using a simplified kinetic mechanism, using the experimental data of VOC conversion for a further model verification. The suggested reactor models accurately predicted the effect of airflow rate, while exhibiting limitations for the effect of different reactor diameters. Therefore, a computational fluid dynamics (CFD) investigation is needed for an accurate modeling of the VOCs oxidation reaction, implementing the developed analytical expression for reducing the computational workload. By combining the developed model with a CFD simulator, it would be possible to simulate several reactors, also at full-scale, for predicting their performance and identifying optimal configurations.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Air treatment, AOPs, Reaction modeling, Reactor scale-up, UV irradiation, VOCs abatement
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-228697 (URN)10.1016/j.cej.2018.05.009 (DOI)000434467000056 ()2-s2.0-85046649604 (Scopus ID)
Funder
Mistra - The Swedish Foundation for Strategic Environmental Research
Note

QC 20180530

Available from: 2018-05-30 Created: 2018-05-30 Last updated: 2018-08-18Bibliographically approved
Wan, W., Engvall, K., Yang, W. & Möller, B. F. (2018). Experimental and modelling studies on condensation of inorganic species during cooling of product gas from pressurized biomass fluidized bed gasification. Energy, 153, 35-44
Open this publication in new window or tab >>Experimental and modelling studies on condensation of inorganic species during cooling of product gas from pressurized biomass fluidized bed gasification
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 153, p. 35-44Article in journal (Refereed) Published
Abstract [en]

In a biomass gasification process, condensation of inorganic species can cause problems such as corrosion and deposition on the downstream equipment. In this work, in order to investigate the condensation of inorganics during the gas cooling step of the biomass gasification system, both experimental and modelling studies were conducted. Experiments were performed on a pilot-scale steam/oxygen blown fluidized bed gasification facility. A CO2 cooled probe was located at the head of a filter to condense inorganic species. Five thermocouples were used to monitor the probe temperature profile. Deposits on the probe were characterized using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) to analyze the elemental composition of deposits. A process model based on the local chemical and phase equilibriums was developed using software SimuSage to predict both release and condensation of inorganics. A customized thermodynamic database extracted from the FactSage 7.1 was used during model calculations. Two cases including with and without addition of bed material were calculated. Results show that the identified elemental compositions of deposit under different gas cooling temperatures reasonably agree with the elemental compositions predicted by model calculations. This demonstrates that the established model and the customized thermodynamic data are valid. A large amount of carbon is identified in the deposit of low temperature probe sections, which may come from the condensed tar. Additionally, a temperature window is found, where melts are formed during gas cooling.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Biomass, Inorganics, Condensation, Gasification
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-234209 (URN)10.1016/j.energy.2018.04.031 (DOI)000436651100005 ()2-s2.0-85046675283 (Scopus ID)
Note

QC 20180905

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-11-29Bibliographically approved
Wan, W., Engvall, K. & Weihong, Y. (2018). Model investigation of condensation behaviors of alkalis during syngas treatment of pressurized biomass gasification. Chemical Engineering and Processing, 129, 28-36
Open this publication in new window or tab >>Model investigation of condensation behaviors of alkalis during syngas treatment of pressurized biomass gasification
2018 (English)In: Chemical Engineering and Processing, ISSN 0255-2701, E-ISSN 1873-3204, Vol. 129, p. 28-36Article in journal (Refereed) Published
Abstract [en]

In order to eliminate problems such as corrosion and ash deposition caused by alkalis, effects of the biomass composition and the pressure of syngas in the downstream process on condensation of alkalis in a wood steam/oxygen blown fluidized bed gasification process are investigated based on a model. This model is established by combining Aspen Plus with SimuSage. Aspen Plus is applied to predict the composition of major gas species formed by C, H, O, N, S and Cl, using empirical correlations to predict the yields of non-equilibrium substances. SimuSage is used to study the release and condensation of inorganics associated with the minor elements (Al, Ca, Fe, K, Mg, Na, P, Si and Ti) based on a customized thermodynamic database. Results show that carbonation reactions between alkalis and CO/CO2 can be occurred during gas cooling, leading to form alkali carbonates in the condensed phase. The temperature window forming melts varies with the change of the downstream pressure of syngas and the elemental composition of biomass. As the syngas pressure in the downstream process decreases, the initial temperature of forming melts during gas cooling is reduced. For biomass lower in K/Cl ratio, the condensate with the largest mass formed during gas cooling is potassium chloride. The condensation rate of Cl increases with the decrease of the K/Cl ratio in biomass.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Alkali metal, Biomass, Condensation, Gasification
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-228721 (URN)10.1016/j.cep.2018.05.001 (DOI)000435059000004 ()2-s2.0-85046685389 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20180530

Available from: 2018-05-30 Created: 2018-05-30 Last updated: 2018-07-02Bibliographically approved
Wan, W., Engvall, K. & Weihong, Y. (2018). Novel Model for the Release and Condensation of Inorganics for a Pressurized Fluidized-Bed Gasification Process: Effects of Gasification Temperature. ACS OMEGA, 3(6), 6321-6329
Open this publication in new window or tab >>Novel Model for the Release and Condensation of Inorganics for a Pressurized Fluidized-Bed Gasification Process: Effects of Gasification Temperature
2018 (English)In: ACS OMEGA, ISSN 2470-1343, Vol. 3, no 6, p. 6321-6329Article in journal (Refereed) Published
Abstract [en]

A model is established to investigate the release and condensation of inorganics for a wood steam/oxygen-blown fluidized-bed gasification process. In the established model, fates of major elements (C, H, O, N, S, and Cl) and minor elements (Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Ti, and Zn) are modeled separately. The composition of gaseous species involving major elements is predicted using Aspen Plus based on a semiempirical model. The release of minor elements and the condensation of inorganics are predicted using software SimuSage. The combination of Aspen Plus with SimuSage is achieved by manually inputting the stream parameters calculated from Aspen Plus into SimuSage. On the basis of this developed model, effects of gasification temperature on the condensation of Na-, K-, and Cl-containing species during gas cooling are studied. Results show that the process model established by combining Aspen Plus and SimuSage is valid and can be used to investigate the release of inorganics during gasification and condensation of inorganics during gas cooling. Under the investigated gasification conditions, regardless of the bed material, there are two temperature ranges within which no salt melt is formed during gas cooling. As the gasification temperature increases, the high-temperature range without salt melt formation becomes successively wider.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-232415 (URN)10.1021/acsomega.8b00019 (DOI)000436340500045 ()2-s2.0-85046646445 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20180726

Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2018-07-26Bibliographically approved
H. Moud, P., Kantarelis, E., J. Andersson, K. & Engvall, K. (2017). Biomass pyrolysis gas conditioning over an iron-based catalyst for mild deoxygenation and hydrogen production. Fuel, 211, 149-158
Open this publication in new window or tab >>Biomass pyrolysis gas conditioning over an iron-based catalyst for mild deoxygenation and hydrogen production
2017 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 211, p. 149-158Article in journal (Other academic) Published
Abstract [en]

Bio-crude is a renewable source for production of valuable energy carriers. Prior to its utilization, a conditioning step of the raw pyrolysis gas can be beneficial before the bio-crude is converted via catalytic hydrodeoxygenation (HDO) into liquid hydrocarbon products, or via steam reforming (SR) to synthesis gas/hydrogen. An experimental small industrial scale study for the chemistry of atmospheric pressure pyrolysis gas conditioning resulting in bio-crude deoxygenation and a hydrogen-rich gas using an iron-based catalyst without addition of hydrogen or steam is presented and discussed. Following a short catalyst stabilization period with fluctuating bed temperatures, the catalyst operated near 450°C at a space velocity of 1100 h-1 for 8 hours under stable conditions during which no significant catalyst deactivation was observed. Experimental results indicate a 70-80% reduction of acetic acid, methoxy phenols, and catechol, and a 55-65% reduction in non-aromatic ketones, BTX, and heterocycles. Alkyl phenols and phenols were least affected, showing a 30-35% reduction. Conditioning of the pyrolysis gas resulted in a 56 % and a 18 wt% increase in water and permanent (dry) gas yield, respectively, and a 29 % loss of condensable carbon. A significant reduction of CO amount (-38 %), and production of H2 (+1063 %) and CO2 (+36 %) over the catalyst was achieved, while there was no or minimal change in light hydrocarbon content. Probing the catalyst after the test, the bulk phase of the catalyst was found to be magnetite (Fe3O4) and the catalyst exhibited significant water gas shift (WGS) reaction activity. The measured gas composition during the test was indicative of no or very limited Fischer-Tropsch (FT) CO /CO2 hydrogenation activity and this infers that also the active surface phase of the catalyst during the test was Fe-oxide, rather than Fe-carbide. The results show that iron-based materials are potential candidates for application in a pyrolysis gas pre-conditioning step before further treatment or use, and a way of generating a hydrogen-enriched gas without the need for bio-crude condensation.

Keywords
Bio-crude conditioning, bio-crude upgrading, gas conditioning, deoxygenation, water-gas shift
National Category
Other Chemical Engineering Other Chemistry Topics
Research subject
Chemical Engineering; Chemistry
Identifiers
urn:nbn:se:kth:diva-213136 (URN)10.1016/j.fuel.2017.09.062 (DOI)000413449600017 ()2-s2.0-85029589987 (Scopus ID)
Projects
Energiforsk
Funder
Swedish Energy Agency
Note

QC 20170830

Available from: 2017-08-29 Created: 2017-08-29 Last updated: 2017-11-14Bibliographically approved
Mesfun, S., Lundgren, J., Toffolo, A., Lindbergh, G., Lagergren, C. & Engvall, K. (2017). Integration of an electrolysis unit for producer gas conditioning in a bio-SNG plant. In: 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017: . Paper presented at 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017.
Open this publication in new window or tab >>Integration of an electrolysis unit for producer gas conditioning in a bio-SNG plant
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2017 (English)In: 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Producer gas from biomass gasification contains impurities like tars, particles, alkali salts and sulfur/nitrogen compounds. As a result a number of process steps are required to condition the producer gas before utilization as a syngas and further upgrading to final chemicals and fuels. Here, we study the concept of using molten carbonate electrolysis cells (MCEC) both to clean and to condition the composition of a raw syngas stream, from biomass gasification, for further upgrading into SNG. A mathematical MCEC model is used to analyze the impact of operational parameters, such as current density, pressure and temperature, on the quality and amount of tailored syngas produced. Investment opportunity is evaluated as an economic indicator of the processes considered. Results indicate that the production of SNG can be boosted by approximately 50% without the need of an additional carbon source, i.e. for the same biomass input as in standalone operation of the GoBiGas plant.

National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-233923 (URN)2-s2.0-85048615505 (Scopus ID)
Conference
30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2017
Note

cited By 0. QC 20181003

Available from: 2018-09-17 Created: 2018-09-17 Last updated: 2018-10-03Bibliographically approved
Bäbler, M. U., Phounglamcheik, A., Amovic, M., Ljunggren, R. & Engvall, K. (2017). Modeling and pilot plant runs of slow biomass pyrolysis in a rotary kiln. Paper presented at 8th International Conference on Applied Energy (ICAE), OCT 08-11, 2016, Beijing Inst Technol, Beijing, China. Applied Energy, 207, 123-133
Open this publication in new window or tab >>Modeling and pilot plant runs of slow biomass pyrolysis in a rotary kiln
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2017 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 207, p. 123-133Article in journal (Refereed) Published
Abstract [en]

Pyrolysis of biomass in a rotary kiln finds application both as an intermediate step in multistage gasification as well as a process on its own for the production of biochar. In this work, a numerical model for pyrolysis of lignocellulosic biomass in a rotary kiln is developed. The model is based on a set of conservation equations for mass and energy, combined with independent submodels for the pyrolysis reaction, heat transfer, and granular flow inside the kiln. The pyrolysis reaction is described by a two-step mechanism where biomass decays into gas, char, and tar that subsequently undergo further reactions; the heat transfer model accounts for conduction, convection and radiation inside the kiln; and the granular flow model is described by the well known Saeman model. The model is compared to experimental data obtained from a pilot scale rotary kiln pyrolyzer. In total 9 pilot plant trials at different feed flow rate and different heat supply were run. For moderate heat supplies we found good agreement between the model and the experiments while deviations were seen at high heat supply. Using the model to simulate various operation conditions reveals a strong interplay between heat transfer and granular flow which both are controlled by the kiln rotation speed. Also, the model indicates the importance of heat losses and lays the foundation for scale up calculations and process optimization.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Pyrolysis, Biomass, Gasification, Rotary drum, Pilot plant, Process model
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-220465 (URN)10.1016/j.apenergy.2017.06.034 (DOI)000417229300012 ()2-s2.0-85021244091 (Scopus ID)
Conference
8th International Conference on Applied Energy (ICAE), OCT 08-11, 2016, Beijing Inst Technol, Beijing, China
Note

QC 20180103

Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2018-01-03Bibliographically approved
Ghadami Yazdi, M., Moud, P. H., Marks, K., Piskorz, W., Öström, H., Hansson, T., . . . Göthelid, M. (2017). Naphthalene on Ni(111): Experimental and Theoretical Insights into Adsorption, Dehydrogenation, and Carbon Passivation. The Journal of Physical Chemistry C, 121(40), 22199-22207
Open this publication in new window or tab >>Naphthalene on Ni(111): Experimental and Theoretical Insights into Adsorption, Dehydrogenation, and Carbon Passivation
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2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 40, p. 22199-22207Article in journal (Refereed) Published
Abstract [en]

An attractive solution to mitigate tars and also to decompose lighter hydrocarbons in biomass gasification is secondary catalytic reforming, converting hydrocarbons to useful permanent gases. Albeit that it has been in use for a long time in fossil feedstock catalytic steam reforming, understanding of the catalytic processes is still limited. Naphthalene is typically present in the biomass gasification gas and to further understand the elementary steps of naphthalene transformation, we investigated the temperature dependent naphthalene adsorption, dehydrogenation and passivation on Ni(111). TPD (temperature-programmed desorption) and STM (scanning tunneling microscopy) in ultrahigh vacuum environment from 110 K up to 780 K, combined with DFT (density functional theory) were used in the study. Room temperature adsorption results in a flat naphthalene monolayer. DFT favors the dibridge[7] geometry but the potential energy surface is rather smooth and other adsorption geometries may coexist. DFT also reveals a pronounced dearomatization and charge transfer from the adsorbed molecule into the nickel surface. Dehydrogenation occurs in two steps, with two desorption peaks at approximately 450 and 600 K. The first step is due to partial dehydrogenation generating active hydrocarbon species that at higher temperatures migrates over the surface forming graphene. The graphene formation is accompanied by desorption of hydrogen in the high temperature TPD peak. The formation of graphene effectively passivates the surface both for hydrogen adsorption and naphthalene dissociation. In conclusion, the obtained results on the model naphthalene and Ni(111) system, provides insight into elementary steps of naphthalene adsorption, dehydrogenation, and carbon passivation, which may serve as a good starting point for rational design, development and optimization of the Ni catalyst surface, as well as process conditions, for the aromatic hydrocarbon reforming process.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
Keywords
Adsorption, Aromatic hydrocarbons, Catalytic reforming, Charge transfer, Dehydrogenation, Density functional theory, Design for testability, Desorption, Gas adsorption, Gasification, Graphene, Hydrocarbons, Nickel, Passivation, Potential energy, Quantum chemistry, Scanning tunneling microscopy, Steam reforming, Temperature programmed desorption, Adsorption geometries, Attractive solutions, Catalytic steam reforming, Desorption of hydrogen, Hydrocarbon reforming, Naphthalene adsorption, Naphthalene transformation, Temperature dependent, Naphthalene
National Category
Chemical Process Engineering
Identifiers
urn:nbn:se:kth:diva-227088 (URN)10.1021/acs.jpcc.7b07757 (DOI)000413131700047 ()2-s2.0-85031329487 (Scopus ID)
Funder
Swedish Research CouncilSwedish Energy AgencySwedish Foundation for Strategic Research
Note

QC 20180515

Available from: 2018-05-15 Created: 2018-05-15 Last updated: 2019-02-07Bibliographically approved
Zhou, C., Rosén, C. & Engvall, K. (2017). Selection of dolomite bed material for pressurized biomass gasification in BFB. Fuel processing technology, 159, 460-473
Open this publication in new window or tab >>Selection of dolomite bed material for pressurized biomass gasification in BFB
2017 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 159, p. 460-473Article in journal (Refereed) Published
Abstract [en]

Dolomite is considered advantageous as bed material in fluidized bed gasification processes, due to its catalytic tar cracking and anti-sintering properties. However, in case of pressurized fluidized bed gasifiers, the use of dolomite is challenging. High temperature in the presence of steam favors the production of clean syngas due to the intensified cracking of tar in the presence of CaO, whereas it simultaneously increases the tendency of fragmentation of dolomite particles after full calcination. The present study was carried out to examine the influence of the properties of dolomite on the stability of dolomite in a pressurized fluidized bed gasifier, with the aim of determining criteria for dolomite selection. Glanshammar dolomite exhibited a better stability in the mechanital strength after calcination, compared to Sala dolomite. The corresponding change of micro-structure that occurred during dolomite chemical transformation was presented. The crystal pattern and Si distribution in the crystal lattice are the possible explanations for the superior performance of the Glanshammar dolomite compared to the Sala dolomite.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2017
Keywords
Dolomite, Pores, Crystal, Pressurized fluidized bed, Gasification
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-206238 (URN)10.1016/j.fuproc.2017.01.008 (DOI)000397353800050 ()2-s2.0-85012025848 (Scopus ID)
Note

QC 20170517

Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-05-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6326-4084

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