| 1. |
- Ding, Mingyue, et al.
(författare)
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Enhancement of conversion from bio-syngas to higher alcohols fuels over K-promoted Cu-Fe bimodal pore catalysts
- 2017
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 159, s. 436-441
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Tidskriftsartikel (refereegranskat)abstract
- A novel K-promoted Cu-Fe bimodal derived catalyst was designed to optimize the catalytic activity and higher alcohols selectivity in higher alcohols synthesis (HAS). The characterization results indicated that the Cu-Fe bimodal derived catalyst presented the bimodal pore structures. The adding of K promoter increased the BET surface area and promoted the dispersion of Cu and Fe species in the bimodal pores without destroying the bimodal structure, whereas the excessive adding of potassium resulted in easily the aggregation of bimetal active species. Incorporation of moderate K content enhanced the reduction of Cu and Fe species and promoted the formation of active bimetal species for HAS, while the bimodal derived catalyst with excessive K content restrained the reduction of bimetal particles, decreasing the catalytic activity for higher alcohols synthesis. In addition, the gradual increasing of K content in the Cu-Fe bimodal derived catalyst strengthened the interaction of K and bimetal active species, which was combined with the “confinement effect” of bimodal pore structures, shifting product distribution towards C2 + OH.
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| 2. |
- Zhang, Zhe, et al.
(författare)
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Inhibition of carbon steel corrosion in phase-change-materials solution by methionine and proline
- 2016
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 111, s. 675-689
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of the 1045 carbon steel corrosion by methionine and proline in PCMs solution have been investigated. Electrochemical measurements show that these inhibitors can protect steel against corrosion, with a maximal protection efficiency up to 95.0% by methionine/proline compound inhibitor at molar ratio equal to 5:3. All inhibitors act as anodic-type inhibitor. FESEM, EDS, XRD characterization indicates that the corrosion of steel starts from pitting corrosion of Cl− ion, and gradually evolves into a general corrosion. The NH4FePO4·nH2O, Fe2O3 are the main corrosion products. XPS study confirms that Met and Pro molecule can adsorb on steel surface and form inhibition films. The inhibition mechanism was further investigated through theoretical modeling studies.
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| 3. |
- Chen, Xu, et al.
(författare)
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Catalytic fast pyrolysis of biomass to produce furfural using heterogeneous catalysts
- 2017
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 0165-2370 .- 1873-250X. ; 127, s. 292-298
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Tidskriftsartikel (refereegranskat)abstract
- Furfural is a valuable chemical, the production of furfural from renewable biomass resources becomes more attractive in recent years. In this study, biomass fast pyrolysis with heterogeneous catalysts (titanium compounds (TiN, TiO2 and TiOSO4) and metal nitrides (MoN, GaN and VN)) for furfural production was investigated experimentally by means of pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS). The measurement results indicated that TiN and GaN promoted the furfural compounds production notably mainly through direct decomposition of oligosaccharides. The formation of furfural was promoted when the amount of TiN was increased, and the yield of furfural formed was about 5.5 times the size of that from non-catalytic pyrolysis when TiN/cellulose mass ratio was 4. The furfural yield decreased when the pyrolysis residence time increased from 10 to 30 s, which suggests competitive reactions (formation of 1, 6-anhydro-beta.-D-glucopyranose) against the formation of furfural. TiN, as a catalyst for fast pyrolysis towards furfural production, can be well applied to agriculture biomass residues. Comparing three biomass residues: corncob, wheat straw and cotton stalk, corncob showed higher furfural yield due to the higher holocellulose content, while wheat straw showed higher furfural selectivity.
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| 4. |
- Göransson, Kristina, et al.
(författare)
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An experimental study on catalytic bed materials in a biomass dual fluidised bed gasifier
- 2015
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 81, s. 251-261
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Tidskriftsartikel (refereegranskat)abstract
- A study on in-bed material catalytic reforming of tar/CH4 has been performed in the 150 kW allothermal gasifier at Mid Sweden University (MIUN). The major challenge in biomass fluidised-bed gasification to produce high-quality syngas, is the reforming of tars and CH4. The MIUN gasifier has a unique design suitable for in-bed tar/CH4 catalytic reforming and continuously internal regeneration of the reactive bed material. This paper evaluates the catalytic effects of olivine and Fe-impregnated olivine (10%wtFe/olivine Catalyst) with reference to silica sand in the MIUN dual fluidised bed (DFB) gasifier. Furthermore, a comparative experimental test is carried out with the same operation condition and bed-materials when the gasifier is operated in the mode of single bubbling fluidised bed (BFB), in order to detect the internal regeneration of the catalytic bed materials in the DFB operation. The behaviour of catalytic and non-catalytic bed materials differs when they are used in the DFB and the BFB. Fe/olivine and olivine in the BFB mode give lower tar and CH4 content together with higher H-2 + CO concentration, and higher H-2/CO ratio, compared to DFB mode. It is hard to show a clear advantage of Fe/olivine over olivine regarding tar/CH4 catalytic reforming. (C) 2015 Elsevier Ltd. All rights reserved.
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| 5. |
- Göransson, Kristina, et al.
(författare)
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Biogas production from biological methanation of syngas
- 2018
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Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 512-515
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Konferensbidrag (refereegranskat)abstract
- Biogas to be used as gas vehicle fuel is a highly potential source to meet transport fuel demand and give a significant contribution to the Swedish target: vehicle fleet independent of fossil fuels by 2030. At present the biogas market is limited by the amount of available organic waste and the associated infrastructure. To overcome these issues, biomass could either be gasified into syngas and synthesized into bio-SNG (Synthetic Natural Gas) through catalytic methanation, or biomass gasification could be integrated into the biogas system to produce methane through biological methanation. Biomass gasification integrated in biological methanation is a relatively new idea and technology. Syngas conversion to methane by anaerobic cultures is practically unexplored, and few reports are available on this subject. Nevertheless, the pathway has been receiving intensive attractions and R&D recent years. For this purpose, a novel pathway by integrating biomass gasification into biogas system is studied in detail. This paper reviews the whole process from integration of biomass gasification into the biogas system to methane production through biological methanation: Biomass gasification > H2+CO > Biogas digester > Upgrading > Natural gas network.
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| 6. |
- Göransson, Kristina, et al.
(författare)
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Internal tar/CH4 reforming in a biomass dual fluidised bed gasifier.
- 2015
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Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 5, s. 355-366
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Tidskriftsartikel (refereegranskat)abstract
- An internal reformer is developed for in situ catalyticreforming of tar and methane (CH4) in allothermal gasifiers.The study has been performed in the 150 kW dual fluidised bed (DFB) biomass gasifier at Mid Sweden University(MIUN). The MIUN gasifier is built for research onsynthetic fuel production. Reduction of tars and CH4 (exceptfor methanation application) in the syngas is a major challengefor commercialization of biomass fluidised-bed gasificationtechnology towards automotive fuel production. The MIUN gasifier has a unique design with an internal reformer, where intensive contact of gas and catalytic solids improves the reforming reactions. This paper presents an initial study on the internal reformer operated with and without Ni-catalytic pellets, by evaluation of the syngas composition and tar/CH4 content. A novel application of Ni-catalyst in DFB gasifiers is proposed and studied in this work. It can be concluded that the reformer with Ni-catalytic pellets clearly gives a higher H2 content together with lower CH4 and tar contents in the syngas than the reformer without Ni-catalytic pellets. The gravimetric tar content decreases down to 5 g/m3 and the CH4 content down below 6 % in the syngas. The tar content can be decreased further to lower levels, with increased gas contact to the specific surface area of the catalyst and increased catalyst surface-to-volume ratio. The new design in the MIUN gasifier increases the gasification efficiency, suppresses the tar generation and upgrades the syngas quality.
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| 7. |
- Henschel, Till, et al.
(författare)
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A study on the pyrolysis behaviour of different biomass fuels using thermogravimetry and online gas analysis
- 2016
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Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 1290-1293
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Konferensbidrag (refereegranskat)abstract
- Fuel availability and flexibility are important issues for biomass-based heat/power and advanced biofuel plants. The physical and chemical properties of biomass feedstocks vary from one to others to a great degree, which must be taken care of for the reactor design/operation, system optimization and blend feedstock application. In this work, the biomass property is evaluated based on pyrolysis behavior of biomass fuels by means of TGA and online gas analysis. Wood, pine bark, peat, straw, black liquor and microalgae are chosen as the biomass feedstocks for the pyrolysis study. The measurement results show high volatile content for algae and black liquor (around 85%) and low volatile content for pine bark and peat (around 69%). Differently from woody biomass, the DTG curve of straw has a single dominant peak at much lower temperature, which suggests a dominant component of hemicellulose in biomass, while algae and peat have a broader temperature specturm of devolatilization but much lower peak temperature. CO2 is released first and H2 later in the pyrolysis process for all biomass feedstocks, whileas the peak of CO formation follows CO2 formation trend for most feedstocks used, except for peat and pine bark which give a peak later at high temperature. This indicates secondary reactions of tar cracking, steam reforming and char gasification.
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| 8. |
- Hu, Junhao, et al.
(författare)
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Co-gasification of coal and biomass : Synergy, characterization and reactivity of the residual char
- 2017
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 244, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The synergy effect between coal and biomass in their co-gasification was studied in a vertical fixed bed reactor, and the physic-chemical structural characteristics and gasification reactivity of the residual char obtained from co-gasification were also investigated. The results shows that, conversion of the residual char and tar into gas is enhanced due to the synergy effect between coal and biomass. The physical structure of residual char shows more pore on coal char when more biomass is added in the co-gasification. The migration of inorganic elements between coal and biomass was found, the formation and competitive role of K2SiO3, KAlSiO4, and Ca3Al2(SiO4)(3) is a mechanism behind the synergy. The graphization degree is enhanced but size of graphite crystallite in the residual char decreases with biomass blending ratio increasing. TGA results strongly suggest the big difference in the reactivity of chars derived from coal and biomass in spite of influence from co-gasification.
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| 9. |
- Liu, Huihui, et al.
(författare)
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Hydrothermal carbonization of natural microalgae containing a high ash content
- 2019
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 249, s. 441-448
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Tidskriftsartikel (refereegranskat)abstract
- The potential to convert natural microalgae (Scenedesmus) into solid fuels by hydrothermal carbonization (HTC) was evaluated. The deashing microalgae (DA) were obtained by acid-washing natural microalgae (NM) with HCl. The deashing efficiency was high from 44.66% for NM to 14.45% for DA. HTC carried out at temperature in the range from 180 to 260 degrees C with this two types feedstock (i.e. NM and DA). The results showed that DA-derived hydrochars had good physicochemical and fuel properties compared with that of NM-derived hydrochars. HTC process of DA was mainly based on polymerization, and the hydrolysis process was short. The hydrochars obtained from DA at 220 degrees C (HC-D220) had the highest value of 51.86% with a carbon content and fixed carbon content 1.15 and 1.33 times, respectively, greater than that of DA. The high heating value (HHV) of HC-D220 reached 26.64 MJ/kg which is equivalent to medium-high calorific coal. The thermogravimetric analysis (TG) demonstrated that the hydrochars derived from DA have good combustion properties with stable at high temperature zones. They can easily mix with coal or replace coal in combustion application. The results of this study revealed that natural microalgae can be utilized by hydrothermal carbonization to generate renewable fuel resources.
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| 10. |
- Liu, H., et al.
(författare)
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Physicochemical characteristics and pyrolysis kinetics of hydrothermal carbon from natural Scenedesmus
- 2019
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Ingår i: Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering. - : Chinese Society of Agricultural Engineering. - 1002-6819. ; 35:14, s. 235-242
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Tidskriftsartikel (refereegranskat)abstract
- In order to explore the utilization of natural microalgae, the natural Scenedesmus was selected to carry out hydrothermal carbonization experiments, and the characterization of its hydrochars was determined using Fourier transform infrared spectroscopy, X-ray diffraction analysis, X-ray fluorescence spectroscopy, environmental scanning electron microscopy and thermogravimetric analyzer. The results showed that the ash content of natural Scenedesmus was 44.66%, and the lipid and protein content of natural Scenedesmus were 1.4% and 15.1%, respectively. The natural microalgae ash components were mostly water-insoluble components. The main components included (Mg0.064Ca0.936CO3), SiO2, NaCl, Al2O3, CaSO4, Mg3S2O8(OH)2. After hydrothermal carbonization treatment, NaCl was dissolved in water, and the water-insoluble components were enriched in hydrochars. Compared with the natural Scenedesmus, the ash content of hydrochars increased, in the range from 57.41% to 71.47%. It was worth noting that the natural Scenedesmus and its derived hydrochars had no fixed carbon. With the increase of hydrothermal temperature, the hydrothermal carbon yield decreased from 47.29% (180℃) to 43.01% (240℃). This phenomenon was on account of the organic components in the natural Scenedesmus underwent hydrolysis, dehydration, decarboxylation, aromatization, condensation and polymerization. The carbon remaining ratio was the largest, the oxygen was the smallest, and the remaining ratios of carbon, hydrogen and oxygen decreased as the hydrothermal temperature increased. For HC-240, the removal rates of H and O were 69.88% and 93.88%, respectively, and the C remaining ration rate was 33.97%. The O/C molar ratio of hydrochars decreased from 1.45 to 0.28. Dehydration and decarboxylation were the main pathways in hydrothermal carbonization of the natural Scenedesmus, and the demethylation pathway was negligible. Oxygen was removed in the form of H2O and CO2. The degree of carbonization was enhanced and hydrochars had the potential to be applied to solid fuels. Since hydrochars contained a large amount of ash, its calorific value was in the range of 8.43-9.67 MJ/kg. Hence, the pretreatment of deashing was a necessary process. The hydrothermal carbonization treatment effectively improved the pore structure of hydrochars, and the absorption-desorption capacity of hydrochars was obviously enhanced. Compared with natural Scenedesmus (4.36 m2/g), the specific surface area of hydrochars was in the range of 28.7-35.26 m2/g. The natural Scenedesmus had a dense block-like without pores or pathways. However, the morphologies of hydrochars changed significantly. The fragmentation and porosity of hydrochars increased, which attributed to the release of volatile matter during hydrothermal carbonization process and chemical bond decomposition of feedstock. The thermogravimetric analysis experiments were carried out to reveal the pyrolysis characteristics of hydrochars. It was found that the weight loss peak at 300℃ gradually disappeared with the increased of hydrothermal temperature. This was owing to the degree of natural Scenedesmus increased and the volatile matter content decreased. When the hydrothermal temperature was higher than 220℃, the maximum weight loss rate peak moved to the high temperature zone. The pyrolysis kinetics results showed that the thermal stability of hydrochars increased with the increase of hydrothermal temperature. The hydrochars were more hydrophobic than that of the natural Scenedesmus. The research results provide a theoretical reference for the resource utilization of natural microalgae.
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