| 1. |
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| 2. |
- Andersson, Sven-Ingvar, 1943, et al.
(författare)
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Catalyst evaluation using an ARCO pilot unit on North Sea atmospheric residue
- 2009
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Ingår i: Abstract of Papers of the American Chemical Society. - 0065-7727. - 9780841200050
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Konferensbidrag (refereegranskat)abstract
- Most North Sea atmospheric residues are well suited feedstocks to a residue fluid catalytic cracker (RFCC) due to their low metals and asphalthene contents. StatoilHydro have used the circulating ARCO pilot unit at Chalmers University of Technology for pilot scale testing of catalysts and feedstocks since 1984. A comparison with the commercial RFCC unit showed that the converted ARCO unit works quite well and we are confident in the results. This will be exemplified with different cases that have happened since the project started.
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| 3. |
- Andersson, Sven-Ingvar, 1943, et al.
(författare)
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Catalyst evaluation using an ARCO pilot unit on north sea atmospheric residue
- 2010
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Ingår i: Advances in Fluid Catalytic Cracking: Testing, Characterization, and Environmental Regulations. - : CRC Press. - 9781420062557 ; , s. 37-62
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- At the end of the 1970s Statoil cracked a North Sea atmospheric residue for the first time in M. W. Kellogg’s circulating pilot unit in Texas [1]. This pilot unit was quite large, with a capacity of one barrel a day. The test in this pilot unit was very successful and showed that North Sea atmospheric residues were very suitable feedstocks for a residue fluid catalytic cracker, and that North Sea atmospheric residues gave very promising product yields.
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| 4. |
- Andersson, Sven-Ingvar, 1943, et al.
(författare)
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Discrepancies in FCC Catalyst Evaluation of Atmospheric Residues
- 2007
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Ingår i: Studies in Surface Science and Catalysis. - 0167-2991. - 0444530606 ; 166, s. 13-29
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Tidskriftsartikel (refereegranskat)abstract
- Processing of atmospheric residues in fluid catalytic crackers (FCC) is a field of considerable interest today. When this application was new, around 1984, Statoil initiated a test program related to fluid catalytic cracking of North Sea atmospheric residues. Within this program catalysts and feeds are tested in a Micro Activity Test (MAT) reactor at Statoil and in a circulating Arco Pilot Unit at Chalmers.The catalysts are tested with the same atmospheric residue feed that is used in the commercial FCC unit at the Statoil Mongstad refinery in Norway. This is essential because erroneous ranking of the catalysts might otherwise occur. The equilibrium catalyst in a commercial residue FCC unit has normally high metals content. This is simulated by testing the catalysts impregnated by nickel and vanadium and deactivated by the cyclic propene steaming (CPS) method.New catalysts are tested together with a reference catalyst in both the MAT and Pilot Unit reactors. Usually the catalysts show the same ranking in both the MAT and Pilot Unit reactors but there are exceptions. If the matrix properties for two catalysts are different, the ranking of the two catalysts might be different in the MAT and PIlot Unit reactors.
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| 5. |
- Andersson, Sven-Ingvar, 1943, et al.
(författare)
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Pilot unit test of residue type catalysts on North Sea atmospheric residue
- 2009
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Ingår i: Abstract of Papers of the American Chemical Society. - : CRC Press. - 0065-7727.
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Konferensbidrag (refereegranskat)abstract
- In order to study the influence of the zeolite content and the matrix when a North Sea atmospheric residue was cracked, two state-of-the-art catalysts with the same zeolite and RE levels were investigated in the circulating ARCO pilot unit at Chalmers. The results from these tests showed that there was a limit in the size of the zeolite to matrix surface area ratio. The choice of matrix also influenced the product yields. The paper will also contain a review of the optimization studies of residue catalysts that the authors have performed during the years.
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| 6. |
- Belkheiri, Tallal, 1985, et al.
(författare)
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Effect of pH on Kraft Lignin Depolymerisation in Subcritical Water
- 2016
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 30:6, s. 4916-4924
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Tidskriftsartikel (refereegranskat)abstract
- Softwood kraft lignin was depolymerized using subcritical water (623 K and 25 MPa) in a continuous small pilot unit. ZrO2 and K2CO3 were used as catalysts, and phenol was used as capping agent to suppress repolymerization. The effect of pH was investigated by adding KOH in five steps to the feed. The yield of water-soluble organics increased with pH. The yield of bio-oil was also influenced by the pH and varied between 28 and 32 wt %. The char yield on the zirconia catalyst showed a minimum at pH 8.1. The yield of suspended solids was low at pH below 8.1 but increased at higher pH values. The oxygen content in the bio-oil was only 15 wt %, compared to about 26 wt % in the kraft lignin.
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| 7. |
- Belkheiri, Tallal, 1985, et al.
(författare)
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Hydrothermal liquefaction of kraft lignin in sub-critical water: the influence of the sodium and potassium fraction
- 2018
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 8:3, s. 585-595
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Tidskriftsartikel (refereegranskat)abstract
- As a part of developing a hydrothermal liquefaction (HTL) process to valorise lignin, it is important to consider integration possibilities with existing infrastructures in order to obtain an overall positive economic impact. One obvious example is to integrate the HTL process with the kraft pulp mill: transport and storage costs is reduced, the temperature levels on process streams can be matched (energy integration) and the recovery/use of alkali can be made efficient. In this study, softwood kraft lignin was depolymerised using sub-critical water (623 K; 25 MPa) in a continuous, small pilot unit with a flow rate of 2 kg/h. ZrO2, K2CO3/KOH and Na2CO3/NaOH were used as catalytic system, and phenol as the capping agent. The influence of the ratio between sodium and potassium in the feed on the yield and composition of the product stream was investigated. The results showed that bio-oil, water-soluble organics (WSO) and char yields were not remarkably influenced by shifting the catalytic system from potassium to sodium. Moreover, the yields of most phenolic compounds did not change significantly when the sodium fraction was varied in the feed. The amounts of suspended solids in the bio-oil produced showed, however, a diminishing trend, (decrease from 10.8 to 3.8%) when the sodium fraction was increased in the feed, whilst the opposite trend was observed for the heavy oil, which increased from 24.6 to 37.6%.
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| 8. |
- Belkheiri, Tallal, 1985, et al.
(författare)
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Hydrothermal Liquefaction of Kraft Lignin in Subcritical Water: Influence of Phenol as Capping Agent
- 2018
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 32:5, s. 5923-5932
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Tidskriftsartikel (refereegranskat)abstract
- The depolymerization of LignoBoost Kraft lignin in subcritical water, i.e. hydrothermal liquefaction (HTL), was investigated using ZrO 2 , K 2 CO 3 , and KOH as catalysts in a fixed-bed reactor with recirculation. Focus was placed on the effect exerted by the concentration of the phenol in suppressing repolymerization, which is responsible for forming char. Feeds with various concentrations of phenol (2-10%) were investigated, and the results showed that phenol partially prevents repolymerization even at low concentrations. The bio-oil yield of (61.0 ± 2.7) % was fairly stable when the concentration of phenol was varied. In the case of the formation of char on the catalyst, the char yield revealed a weakly decreasing trend (14.6-12.3%) when the amount of phenol in the feed was increased. The results also showed that the phenolic monomers that are alkylated, such as o-/p-cresols, increased significantly with increasing concentrations of phenol, while aromatic compounds, based on a guaiacol ring structure, showed decreasing trends.
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| 9. |
- Belkheiri, Tallal, 1985, et al.
(författare)
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Kraft Lignin Depolymerization in Near-Critical Water: Effect of Changing Co-Solvent
- 2014
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 48:9-10, s. 813-818
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Tidskriftsartikel (refereegranskat)abstract
- As part of developing a process to valorize lignin in a pulp mill with lignin separation, the depolymerisation of lignin to valuable chemicals was investigated in near-critical water. This was done by using methanol as co-solvent and hydrogen donor, phenol to suppress repolymerization (e.g. formation of char), and ZrO2 as a heterogeneous catalyst, with potassium carbonate as a co-catalyst. The reaction was carried out in a continuous flow fixed-bed reactor (500 cm(3)), at 280-350 degrees C and 25MPa. An important aspect is to suppress char formation. Therefore, the char formation was studied by using different concentrations of methanol and phenol. The char yield varied between 14% and 26%. When using methanol as the only co-solvent, the char yield decreased with increasing methanol concentration. Adding phenol resulted in a further decrease. The reactor outlet consisted mainly of two liquid phases, an aqueous and an oil phase, mixed together. The chemical analysis of the aqueous phase showed the presence of mainly phenolic compounds, for instance guaiacol, catechol, phenol and cresol.
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| 10. |
- Boström, Zebastian, 1983, et al.
(författare)
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Comparison of Microporous/Mesoporous and Microporous HZSM-5 as Catalyst for Friedel-Crafts Alkylation of Toluene with Ethene
- 2014
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:54, s. 28786-28793
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Tidskriftsartikel (refereegranskat)abstract
- In this work we investigated the effect of mesopores in a standard zeolite used as a catalyst for Friedel-Crafts alkylation of toluene with ethene. A cationic polymer was used for templating mesopores in a microporous ZSM-5 framework. The mesopore-containing zeolite was compared with a regular zeolite with only micropores with respect to conversion, yield and selectivity. The two NaZSM-5 materials were prepared with the same Si/Al molar ratio and diffuse reflection infrared Fourier transform spectroscopy (DRIFT-FTIR) confirmed that the acidity of the ion-exchanged forms (HZSM-5) were identical. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) were used to determine the particle size of the zeolites, which was similar for the two HZSM-5 materials and nitrogen sorption was used to determine the surface area and pore size distribution. X-ray diffraction (XRD) analysis displayed typical crystalline diffraction patterns for the ZSM-5 framework for both the microporous/mesoporous and the microporous ZSM-5 materials. The results from catalytic testing show an increase in the overall conversion of toluene for the zeolite that contains mesopores. Furthermore, a higher product yield (C 9 ) is obtained for this catalyst. The increase in yield and conversion is most likely due to the mesopores; however, incorporation of mesopores in the microporous ZSM-5 framework gives only minor effects on selectivity with respect to mono- vs. dialkylation, and ortho:meta:para ratio. Consequently, this work shows that the presence of mesopores in a microporous ZSM-5 framework is beneficial for the reaction in terms of conversion of starting material and reaction yield but does not markedly affect the product composition. © 2014 the Partner Organisations.
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| 11. |
- Lyckeskog, Huyen, 1985, et al.
(författare)
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Catalytic depolymerisation and conversion of Kraft lignin into liquid products using near-critical water
- 2014
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 86, s. 67-75
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Tidskriftsartikel (refereegranskat)abstract
- A high-pressure pilot plant was developed to study the conversion of LignoBoost Kraft lignin into bio-oil and chemicals in near-critical water (350◦C, 25 MPa). The conversion takes place in a continuous fixed-bed catalytic reactor (500 cm3) filled with ZrO2 pellets. Lignin (mass fraction of approximately 5.5%) is dispersed in an aqueous solution containing K2CO3(from 0.4% to 2.2%) and phenol (approximately 4.1%).The feed flow rate is 1 kg/h (reactor residence time 11 min) and the reaction mixture is recirculated internally at a rate of approximately 10 kg/h. The products consist of an aqueous phase, containing phenolic chemicals, and a bio-oil, showing an increased heat value (32 MJ/kg) with respect to the lignin feed. The 1-ring aromatic compounds produced in the process are mainly anisoles, alkylphenols, guaiacols and catechols: their overall yield increases from 17% to 27% (dry lignin basis) as K2CO3 is increased.
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| 12. |
- Lyckeskog, Huyen, 1985, et al.
(författare)
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Storage Stability of Bio-oils Derived from the Catalytic Conversion of Softwood Kraft Lignin in Subcritical Water
- 2016
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 30:4, s. 3097-3106
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Tidskriftsartikel (refereegranskat)abstract
- The stability of lignin-derived bio-oil obtained from a continuous process [base (K2CO3)-catalyzed, using phenol as a capping agent] under subcritical conditions of water (25 MPa, 290-370 degrees C) was investigated. The lignin-derived bio-oil obtained was stored at ambient temperature for 2 years. Our results show that the base concentration in the feed solution affects the stability of this lignin-derived bio-oil during its long-term storage. It was found that, at low base concentrations (i.e., 0.4%-1.0%), the yields of all lignin-derived bio-oil fractions were relatively stable. At high base concentrations (i.e., 1.6%-2.2%), however, the yield of high-molecular-weight (high-Mw) structures increased and that of low-molecular-weight (low-Mw) structures decreased after storage. This indicated that the low-Mw materials had been polymerized to form high-Mw materials. In addition, it was found that the yield of gas chromatography-mass spectrometry (GC-MS)-identified compounds (excluding phenol) in this lignin-derived bio-oil decreased from 15% to 11%. This is probably due to the presence of solids in these lignin derived bio-oils, which promotes the catalytic polymerization reactions, suggesting that it is beneficial to remove the solids from this lignin-derived bio-oil in order to enhance its stability. Compared to the results obtained from bio-oil derived from biomass pyrolysis, our results show that bio-oil derived from the conversion of lignin in subcritical water has better chemical stability during long-term storage.
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| 13. |
- Lyckeskog, Huyen, 1985, et al.
(författare)
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The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 170, s. 196-203
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Tidskriftsartikel (refereegranskat)abstract
- The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370 degrees C and its effect on the process was investigated in a continuous flow (1 kg/h). The yields of water-soluble organics (WSO), bio-oil and char (dry lignin basis) were in the ranges of 5-11%, 69-87% and 16-22%, respectively. The bio-oil, being partially deoxygenated, exhibited higher carbon content and heat value, but lower sulphur content than lignin. The main 1-ring aromatics (in WSO and diethylether-soluble bio-oil) were anisoles, alkylphenols, catechols and guaiacols. The results show that increasing temperature increases the yield of 1-ring aromatics remarkably, while it increases the formation of char moderately. An increase in the yields of anisoles, alkylphenols and catechols, together with a decrease in the yield of guaiacols, was also observed.
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| 14. |
- Mattsson, Cecilia, 1970, et al.
(författare)
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Subcritical water de-polymerization of Kraft lignin: A process for future biorefineries. Structural characterization of bio-oil and solids
- 2015
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Ingår i: NWBC 2015 - 6th Nordic Wood Biorefinery Conference. ; , s. 112-119
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Konferensbidrag (refereegranskat)abstract
- A 2D-NMR analysis was carried out on fractionated bio-oil in order to investigate the result of the subcritical water base catalysed de-polymerization of LignoBoost Kraft lignin (350 °C, 25 MPa). It was confirmed that the signals from aliphatic lignin inter-unit linkages, i.e. ß-O-4’, ß-ß’, ß-1’ and ß-5’, had disappeared in all bio-oil fractions (light oil, heavy oil and suspended solids). This means that both aliphatic carbon-oxygen (C-O) and carbon-carbon (C-C) bonds in LignoBoost Kraft lignin have been broken and an effective de-polymerization has occurred. However, re-polymerization to higher molecular weight (Mw) fractions take place simultaneously. These higher Mw fractions (heavy oil and suspended solids) were found to be re-polymerized macromolecules (Mw distribution 5.4 kDa and 19.5 kDa resp.) with new structural networks based on guaiacol/disubstituted aromatic ethers and polyaromatic hydrocarbon structures tightly bound together. In this work it has been demonstrated that the subcritical water de-polymerization process of LignoBoost Kraft lignin does function; an effective de-oxygenation of LignoBoost Kraft lignin takes place, generating a bio-oil with a low content of atomic oxygen (15 wt.%) suitable for further processing at fossil-based oil refineries.
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| 15. |
- Mattsson, Cecilia, 1970, et al.
(författare)
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Using 2D NMR to characterize the structure of the low and high molecular weight fractions of bio-oil obtained from LignoBoost (TM) kraft lignin depolymerized in subcritical water
- 2016
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 95, s. 364-377
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Tidskriftsartikel (refereegranskat)abstract
- In this work a multilevel analysis approach have been used for characterization of LignoBoostTM kraft lignin and bio-oil produced from LignoBoostTM kraft lignin using a process based on subcritical water (350 degrees C, 25 MPa). LignoBoostTM kraft lignin and the different fractions of the bio-oil (light oil, heavy oil and suspended solids) was characterized with high field NMR (18.8 T, 2D(13)C, H-1-HSQC NMR and C-13-NMR), GPC, GC-MS and elemental composition to improve understanding of the subcritical process. By using high resolution 2D HSQC NMR it was possible determine the chemical structures both on low and high molecular weight fractions of the bio-oil. It was confirmed that the signals from the aliphatic lignin inter-unit linkages, i.e. beta-O-4', beta-beta', beta-1' and beta-5', had disappeared from all of the bio-oil fractions studied. This means that both the aliphatic carbon-oxygen (C-O) and to some extent carbon-carbon (C-C) bonds in LignoBoostTM kraft lignin have been cleaved and an effective depolymerization has occurred. However, re-polymerization into higher molecular weight (Mw) fractions takes place simultaneously. These higher Mw fractions (heavy oil and suspended solids) were found to be re-polymerized macromolecules, with new structural networks based on guaiacol/disubstituted aromatic ethers and polyaromatic hydrocarbon structures bound tightly together. (C) 2016 Elsevier Ltd. All rights reserved.
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| 16. |
- Nguyen Lyckeskog, Huyen, 1985, et al.
(författare)
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Accelerated aging of bio-oil from lignin conversion in subcritical water
- 2017
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Ingår i: Tappi Journal. - : TAPPI. - 0734-1415. ; 16:3, s. 123-141
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Accelerated aging of bio-oil derived from lignin was investigated at different aging temperatures (50 degrees C and 80 degrees C) and times (1 hour, 1 day, 1 week, and 1 month). The bio-oil used was produced by the hydrothermal liquefaction of kraft lignin, using phenol as the capping agent, and base (potassium carbonate and potassium hydroxide) and zirconium dioxide as the catalytic system in subcritical water. Elemental composition, molecular weight (by using gel permeation chromatography), and chemical composition (by using gas chromatography-mass spectrometry and 2D nuclear magnetic resonance [18.8 T, DMSO-d(6)]) of the bio-oil were measured to gain better understanding of the changes that occurred after being subjected to an accelerated aging process. The lignin-derived hydrothermal liquefaction bio-oil was quite stable compared with biomass-pyrolysis bio-oil. The yield of the low molecular weight fraction (light oil) decreased from 64.1% to 58.1% and that of tetrahydrofuran insoluble fraction increased from 16.5% to 22.2% after aging at 80 degrees C for 1 month. Phenol and phenolic dimers (Ar-CH2-Ar) had high reactivity compared with other aromatic substituents (i.e., methoxyl and aldehyde groups); these may participate in the polymerization/condensation reactions in the hydrothermal liquefaction bio-oil during accelerated aging. Moreover, the 2D heteronuclear single quantum coherence nuclear magnetic resonance spectra of the high molecular weight fraction (heavy oil) in the aged raw oil in the aromatic region showed that the structure of this fraction was a combination of phenol-alkyl patterns, and the guaiacol cross-peaks of Ar-2, Ar-5, and Ar-6 after aging indicate that a new polymer was formed during the aging process. Application: Pulp mill personnel can use this information when considering technology to extract lignin from black liquor and process it further into bio-oil.
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| 17. |
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| 18. |
- Nguyen Lyckeskog, Huyen, 1985, et al.
(författare)
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Thermal stability of low and high Mw fractions of bio-oil derived from lignin conversion in subcritical water
- 2017
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 7:4, s. 401-414
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Tidskriftsartikel (refereegranskat)abstract
- The thermal stability of bio-oil influences its application in industry and is, therefore, a very important factor that must be taken into consideration. In this study, the stability of low and high molecular weight (Mw) fractions of bio-oil obtained from the hydrothermal liquefaction (HTL) of lignin in subcritical water was studied at an elevated temperature (80 °C) for a period of 1 h, 1 day and 1 week. The changes in molecular weight (gel permeation chromatography (GPC)) and chemical composition (gas chromatography–mass spectrometry (GC–MS) and 2D heteronuclear single quantum correlation (HSQC) NMR (18.8 T, DMSO-d6)) of low and high Mw fractions of the HTL bio-oil (i.e. light oil (LO) and heavy oil (HO)) were evaluated before and after ageing. It was found that only a slight formation of high Mw insoluble structures was obtained during ageing at elevated temperature for 1 week: 0.5% for the LO and 3.1% for the HO. These higher Mw moieties might be formed from different polymerisation/condensation reactions of the reactive compounds (i.e. anisoles, guaiacols, phenols, methylene (–CH2–) groups in phenolic dimers and xanthene). The high Mw insolubles in both the LO and the HO were analysed for structural composition using 2D HSQC NMR to obtain a better understanding of the changes in the composition of bio-oil fractions during the accelerated ageing process. In addition, a chemical shift database in DMSO-d6 was analysed for a subset of phenolic model compounds to simplify the interpretation of the 2D HSQC NMR spectra.
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