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Jafri, Y. (2019). Biofuels from Kraft Black Liquor: Pilot-Scale Gasification Development and Techno-Economic Evaluation of Industrially Relevant Biofuel Production Pathways. (Doctoral dissertation). Luleå University of Technology
Open this publication in new window or tab >>Biofuels from Kraft Black Liquor: Pilot-Scale Gasification Development and Techno-Economic Evaluation of Industrially Relevant Biofuel Production Pathways
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Fuel combustion for transport was responsible for 24% of EU-28 greenhouse gas (GHG) emissions in 2016. Member states are expected to ensure that the share of renewable energy in the transport sector is at least 14% by 2030. Some countries, such as Sweden, have more ambitious targets. By 2030, GHG emissions from domestic transport are to be reduced by 70% relative to 2010 levels. A national emission reduction scheme launched in 2018 obliges suppliers of diesel and petrol to reduce their GHG footprints annually by a pre-determined amount, which could further stimulate demand for drop-in biofuels, and potentially even high blend alternatives. However, recent changes to Swedish domestic policy and the EU-wide RED sustainability criteria mean that biodiesel from some common crop-based biomaterials may no longer qualify for certain important tax benefits or count towards the 2030 renewables target. Given Sweden’s extensive forest products industry, woody residue and by-products, such as branches, toppings and black liquor (BL) are viewed as strategically important feedstock for the production of RED-compliant biofuels. Upgrading kraft BL to biofuels can also potentially help pulp mills expand their product base. Two conversion routes are seen as industrially relevant in the short-to-medium term: (a) gasification-catalytic synthesis, (b) liquefaction-hydrotreatment.

The production of methanol and dimethyl ether from kraft BL has been demonstrated extensively in a pilot facility, although a complete analysis of technical performance based on experimental measurements has not been performed previously. Since BL is not transportable, the biofuel production potential of a mill is effectively set by its pulp throughput, which limits potential economies-of-scale. BL is rich in catalytically active sodium compounds and blending it with other woody residue-based feedstock, such as pyrolysis oil (PO) before gasification allows the partial decoupling of biofuel production capacity from available black liquor volumes. Several commercial actors are currently testing the technical viability of using liquefaction-hydrotreatment for the production of renewable petrol and diesel blendstock from kraft lignin. The first step in both cases is co-located at a pulp mill. Depending on the desired end product and production route, subsequent upgrading and finishing may be carried out at a pulp mill or a crude oil refinery, with a resulting impact on both production economics and energetic performance that is complex and little studied. 

The main aim of this thesis is to evaluate the technical and economic viability of kraft liquor-based biofuel production pathways that are adjudged to be commercially relevant, that is they are seen as commercially deployable in the short-to-medium term at the present time. The catalytic co-gasification of PO and BL was studied in pilot-scale experiments, and resulting data were used to calculate key performance indicators. Blending BL with the more energy-rich PO led to an increase in cold gas efficiency without adversely affecting organic carbon conversion, which remained nearly complete at blend ratios of up to 20 wt.% PO. There were no signs of an increase in either soot or tar formation. Analyses of gas condensate samples found traces of unknown uncharged forms of sulfur and while sulfur reduction efficiencies were generally high, balance closures could not consistently be obtained owing to analytical difficulties. Further study appears warranted. Pilot-scale entrained-flow gasification experiments are expensive and time consuming. An alternative is thermodynamic equilibrium calculations, which were found to predict the flows of major syngas and slag constituents with a high degree of accuracy, subject to expected deviations in methane formation and sulfur distribution.

An analysis of production economics found nth-of-a-kind investments in gasification-based methanol and lignin liquefaction and hydrotreatment-based drop-in biofuels to be profitable for a range of sizes, although the latter pathway, which is currently prioritized for development in the short-run was at a lower level of technology maturity. In assessing the overall energetic performance of a pulp mill-integrated kraft BL-based biofuel production, explicit consideration of mill energy balance is needed to avoid misestimation. Modern market pulp mills with a large energy surplus, normally exported as electricity, are at an advantage. There are indications that relatively small gasification units of around 100 MW could potentially also be profitable, which means biofuel production facilities based on both principle conversion tracks could be used to debottleneck pulp production by relieving recovery boiler capacity constraints, although the viability of such an approach is mill specific and requires detailed investigation. While co-gasifying black liquor with pyrolysis oil or blending syngas from unblended black liquor with electrolysis hydrogen offers better carbon utilization, larger biofuel production potentials and a more diverse feedstock base, gasification of unblended black liquor comes out as the lowest cost option for producing drop-in biofuels from part-streams. 

Place, publisher, year, edition, pages
Luleå University of Technology, 2019
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
biofuels, black liquor, pyrolysis oil, gasification, drop-in, energy systems, techno-economic
National Category
Energy Systems Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-75787 (URN)978-91-7790-433-5 (ISBN)978-91-7790-434-2 (ISBN)
Public defence
2019-10-11, E632, E Building, Luleå, 12:30 (English)
Opponent
Supervisors
Available from: 2019-09-02 Created: 2019-08-30 Last updated: 2019-12-16Bibliographically approved
Jafri, Y., Wetterlund, E., Anheden, M., Kulander, I., Håkansson, Å. & Furusjö, E. (2019). Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 1. Product yields & energetic performance. Energy, 166, 401-413
Open this publication in new window or tab >>Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 1. Product yields & energetic performance
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2019 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 166, p. 401-413Article in journal (Refereed) Published
Abstract [en]

Forest-based biofuels are strategically important in forest-rich countries like Sweden but the technical performance of several promising production pathways is poorly documented. This study examines product yields and energy efficiencies in six commercially relevant forest-based “drop-in” and “high blend” biofuel production pathways by developing detailed spreadsheet energy balance models. The models are in turn based on pilot-scale performance data from the literature, supplemented with input from technology developers and experts. In most pathways, biofuel production is integrated with a market pulp mill and/or a crude oil refinery. Initial conversion is by pyrolysis, gasification or lignin depolymerization and intermediate products are upgraded by hydrotreatment or catalytic synthesis.

While lignin oil (LO) hydrodeoxygenation had the highest expanded system efficiency, considerable uncertainty surrounds product yields owing to absence of suitable experimental data on LO upgrading. Co-feeding vacuum gas oil and fast pyrolysis oil in a fluidized catalytic cracker has a complex and uncertain effect on fossil yields, which requires further investigation. Co-locating bio-oil hydrotreatment at the refinery improves heat utilization, leading to higher system efficiencies. Explicit consideration of mill type and energy requirements is required to avoid performance misestimation as an assumption of energy surplus can confer a definite advantage.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Biofuels, Pyrolysis, Gasification, Lignin oil, Energy efficiencies, Product yields
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-71274 (URN)10.1016/j.energy.2018.10.008 (DOI)000455694300035 ()2-s2.0-85056190528 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-07 (inah)

Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2019-08-30Bibliographically approved
Jafri, Y., Wetterlund, E., Anheden, M., Kulander, I., Håkansson, Å. & Furusjö, E. (2019). Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 2, economics, GHG emissions, technology maturity and production potentials. Energy, 172, 1312-1328
Open this publication in new window or tab >>Multi-aspect evaluation of integrated forest-based biofuel production pathways: Part 2, economics, GHG emissions, technology maturity and production potentials
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2019 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 172, p. 1312-1328Article in journal (Refereed) Published
Abstract [en]

Promoting the deployment of forest-based drop-in and high blend biofuels is considered strategically important in Sweden but many aspects of the overall performance of the foremost production technologies are as yet unexamined. This paper evaluates the technology maturity, profitability, investment requirements, GHG performance and Swedish biofuel production potential of six commercially interesting forest-based biofuel production pathways.

Significant heterogeneity in technology maturity was observed. Lack of technical demonstration in industrially representative scales renders the liquefaction-hydrotreatment route for drop-in biofuels less mature than its gasification-catalytic upgrading counterpart. It is a paradox that short-term priority being accorded to pathways with the lowest technology maturity. Nth-of-a-kind investments in (a) gasification-based methanol, (b) hydropyrolysis-based petrol/diesel, and (c) lignin depolymerization-based petrol/diesel were profitable for a range of plant sizes. The profitability of pulp mill-integrated small gasification units (<100 MW) goes against the common perception of gasification being economically feasible only in large scales. New low-cost options for debottlenecking production at recovery boiler-limited kraft mills appear worth investigating. GHG emission reductions ranged from 66 to 95%; a penalty was incurred for high consumption of natural gas-based hydrogen. Swedish biofuel production potentials ranged from 4 to 27 TWh/y but a more feasible upper limit is 12–15 TWh/y.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Biofuels, Gasification, Lignin oil, Pyrolysis oil, Black liquor, Forest residues
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-73052 (URN)10.1016/j.energy.2019.02.036 (DOI)000464488100107 ()2-s2.0-85063629405 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-04-11 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-09-13Bibliographically approved
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
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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
Furusjö, E. & Jafri, Y. (2018). Thermodynamic equilibrium analysis of entrained flow gasification of spent pulping liquors. Biomass Conversion and Biorefinery, 8(1), 19-31
Open this publication in new window or tab >>Thermodynamic equilibrium analysis of entrained flow gasification of spent pulping liquors
2018 (English)In: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 8, no 1, p. 19-31Article in journal (Refereed) Published
Abstract [en]

he main goal of this work is to investigate if thermodynamic equilibrium calculations can be useful for understanding and predicting process performance and product composition for entrained flow gasification of spent pulping liquors, such as black liquor. Model sensitivity to input data is studied and model results are compared to published pilot plant data. The high temperature and the catalytic activity of feedstock alkali make thermodynamic equilibrium a better predictor of product composition than for many other types of biomass and gasification technologies. Thermodynamic equilibrium calculations can predict the flows of the main syngas and slag products with high accuracy as shown by comparison with experimental data with small measurement errors. The main process deviations from equilibrium are methane formation and sulfur distribution between gas and slag. In order to study real process deviations from equilibrium, it is very important to use consistent experimental data. Relatively small errors in the model input, primarily related to fuel composition, can lead to grossly erroneous conclusions. The model sensitivity to fuel composition also shows that the gasification process is sensitive to naturally occurring feedstock variations. Simulations of a commercial-scale gasification process show that cold gas efficiency on sulfur-free basis can reach over 80 % and that greatly improved efficiency can be obtained by reducing ballast present in the form of water or inorganics.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-60579 (URN)10.1007/s13399-016-0225-7 (DOI)000425594800003 ()2-s2.0-85042227019 (Scopus ID)
Funder
Swedish Energy Agency, 38026-1
Note

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

Available from: 2016-11-21 Created: 2016-11-21 Last updated: 2019-08-30Bibliographically approved
Jafri, Y. (2016). Entrained-Flow Gasification of Black Liquor and Pyrolysis Oil: Experimental and Equilibrium Modelling Studies of Catalytic Co-gasification. (Licentiate dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Entrained-Flow Gasification of Black Liquor and Pyrolysis Oil: Experimental and Equilibrium Modelling Studies of Catalytic Co-gasification
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The last couple of decades have seen entrained-flow gasification of black liquor (BL) undergo an incremental process of technical development as an alternative to combustion in a recovery boiler. The ability of the technology to combine chemical recovery with the production of clean syngas renders it a promising candidate for the transformation of chemical pulp mills into integrated forest biorefineries. However, techno-economic assessments have shown that blending BL with the more easily transportable pyrolysis oil (PO) can not only increase the system efficiency for methanol production but remove a significant roadblock to development by partially decoupling production capacity from limitations on black liquor availability.

The verification and study of catalytic co-gasification in an industrially-relative scale can yield both scientifically interesting and practically useful results, yet it is a costly and time-consuming enterprise. The expense and time involved can be significantly reduced by performing thermodynamic equilibrium calculations using a model that has been validated with relevant experimental data. The main objective of this thesis was to study, understand, quantify and compare the gasification behaviour and process performance of black liquor and pyrolysis oil blends in pilot-scale. A secondary objective of this work was to demonstrate and assess the usefulness and accuracy of unconstrained thermodynamic equilibrium modelling as a tool for studying and predicting the characteristics of alkali-impregnated biomass entrained-flow gasification.

The co-gasification of BL/PO blends was studied at the 3 MWth LTU Green Fuels pilot plant in a series of experimental studies between June 2015 and April 2016. The results of the studies showed that the blending of black liquor with the more energy rich pyrolysis oil increased the energetic efficiency of the BLG process without adversely affecting carbon conversion. The effect of blend ratio and reactor temperature on the gasification performance of PO and BL blends with up to 20 wt% PO was studied in order to assess the impact of alkali-dilution in fuel on the conversion characteristics. 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 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.

The validation of thermodynamic equilibrium simulation of black liquor and pyrolysis co-gasifications with experimental data revealed the need to be mindful of errors and uncertainities in fuel composition that can influence predictions of equilibrium temperature. However, provided due care is to taken to ensure the use of accurate fuel composition data, unconstrained TEMs can serve as a robust and useful tool for simulating catalytic entrained-flow gasification of biomass-based feedstocks.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2016
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
Keywords
Black liquor, pyrolysis oil, catalytic gasification, co-gasification, gasification, entrained-flow gasification, pilot-scale
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-60342 (URN)978-91-7583-761-1 (ISBN)978-91-7583-762-8 (ISBN)
Presentation
2016-12-16, F632, Luleå University of Technology, Luleå, 13:00
Opponent
Supervisors
Projects
LTU Biosyngas (Catalytic Gasification)
Funder
Swedish Energy Agency
Available from: 2016-11-14 Created: 2016-11-11 Last updated: 2017-11-24Bibliographically 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
Furusjö, E., Kirtania, K., Jafri, Y., Oller, A. B., Umeki, K., Lundgren, J., . . . Pettersson, E. (2015). Co-gasification of pyrolysis oil and black liquor - a new track for production of chemicals and transportation fuels from biomass (ed.). Paper presented at International conference on thermochemical (TC) biomass conversion science : 02/11/2015 - 05/11/2015. Paper presented at International conference on thermochemical (TC) biomass conversion science : 02/11/2015 - 05/11/2015.
Open this publication in new window or tab >>Co-gasification of pyrolysis oil and black liquor - a new track for production of chemicals and transportation fuels from biomass
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2015 (English)Conference paper, Oral presentation only (Refereed)
Abstract [en]

Pressurized oxygen-blown entrained flow black liquor (BL) gasification, the Chemrec technology, has been demonstrated in a 3 MWth pilot plant in Piteå, Sweden for more than 25,000 h. The plant is owned and operated by Luleå University of Technology since 2013. It is well known that catalytic activity of alkali metals is important for the high reactivity of black liquor, which leads to a highly efficient BL gasification process. The globally available volume of BL is however limited and strongly connected to pulp production. By co-gasifying pyrolysis oil (PO) with BL it is possible to utilize the catalytic activity also for PO conversion to syngas. Adding PO leads to larger feedstock flexibility with the possibility of building larger biofuels plants based on BL gasification technology. This presentation summarizes new results from research activities aimed at developing and assessing the PO/BL co-gasification process. Results from laboratory experiments with PO/BL mixtures show that pyrolysis behavior and char gasification reactivity are similar to pure BL. This means that the decrease in the alkali metal concentration due to the addition of PO in the mixture does not decrease the reactivity. Pure PO is much less reactive. Mixing tests show that the fraction of PO that can be mixed into BL is limited by lignin precipitation as a consequence of PO acidity. Pilot scale PO/BL co-gasification experiments have been executed following design and construction of a new feeding system to allow co-feeding of PO with BL. The results confirm the conclusions from the lab scale study and prove that the co-gasification concept is practically applicable. Process performance of the pilot scale co-gasification process is similar to gasification of BL only with high carbon conversion and clean syngas generation. This indicates that the established BL gasification technology can be used for co-gasification of PO and BL without major modifications.

National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-30507 (URN)45928ae2-f558-4119-8412-5bd4e1769336 (Local ID)45928ae2-f558-4119-8412-5bd4e1769336 (Archive number)45928ae2-f558-4119-8412-5bd4e1769336 (OAI)
Conference
International conference on thermochemical (TC) biomass conversion science : 02/11/2015 - 05/11/2015
Note
Godkänd; 2015; 20151116 (erifur)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-05-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9208-1642

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