| 1. |
- Braz, C. G., et al.
(författare)
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Dynamic modelling of non-isothermal open-cell foam catalyst packings : selective sugar hydrogenation to sugar alcohols as a case study
- 2022
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Ingår i: 32<sup>nd</sup> European Symposium on Computer Aided Process Engineering. - : Elsevier B.V.. ; , s. 73-78
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Bokkapitel (refereegranskat)abstract
- A comprehensive multiphase model was developed for a trickle bed reactor with solid foam packings. Three-dimensional dynamic mass and energy balances in the three phases of heterogeneously catalysed reaction systems were implemented, and the mass and heat transfer resistances in the gas-liquid and liquid-solid phases and inside the pores of the catalyst were included in the model. Hydrogenation of arabinose and galactose mixtures on a ruthenium catalyst supported by carbon-coated aluminium foams was applied as an industrially relevant case study for the multiphase model. The kinetic parameters were estimated with confidence intervals within 10% error, indicating a good accuracy of the parameters, and the model results present a good adjustment to the experimental values. Finally, a sensitivity analysis on several model parameters demonstrated that the model could be applied to industrially sized reactors and various multiphase catalytic systems.
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| 2. |
- Privalova, Elena, et al.
(författare)
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CO2 capture from biogas : absorbent selection
- 2013
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Ingår i: RSC Advances. - : RSC Publishing. - 2046-2069. ; 3:9, s. 2979-2994
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Tidskriftsartikel (refereegranskat)abstract
- The development of proper biogas upgrading technology offers a viable means to utilize biogas in conventional power systems. In this paper, various molecular and ionic solvent systems were evaluated for CO2 removal from biogas in a loop reactor system. The performance of amine solutions, ionic liquids and their mixtures, amino acid salts and solutions blended with piperazine was compared in terms of their CO2 loading capacity. The experimental results revealed that addition of small amounts of piperazine can increase the efficiency of abovementioned solutions on average by 30 vol%. The CO2 capturing capacity of the most promising solvents was in the range of 50-60 L CO2/L absorbent. The regeneration of the solvent mixtures can be challenging since the solvents could loose 16-43 vol% of their initial efficiency upon CO2 release. Ionic liquid [C4mim][acetate] was found to be an efficient VOCs scrubbing media. Moreover, upon use of this ionic liquid, the amount of identified volatile organic compounds (VOCs) in the studied samples was reduced by 65 wt%, while the use of 15 wt% aqueous N-methyldiethanolamine (MDEA) resulted only in 32 wt% reduction in the amount of VOCs.
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| 3. |
- Privalova, E, et al.
(författare)
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CO2 removal with ‘switchable’ versus ‘classical’ ionic liquids
- 2012
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Ingår i: Separation and Purification Technology. - Amsterdam : Elsevier. - 1383-5866 .- 1873-3794. ; 97, s. 42-50
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Tidskriftsartikel (refereegranskat)abstract
- Switchable ionic liquids (SILs) are promising solvents for CO2 separation due to their high CO2 capturing efficiency and easy preparation compared to ‘classical’ ionic liquids. Considering viscosity, the present study has demonstrated that SILs formed at least two times stronger chemical bonds with CO2 than studied classical ionic liquids (ILs). Furthermore, the reversible properties of SILs were confirmed by evaluation of different regeneration methods. On average, molar fractions of CO2 were more than 0.3 outperforming acetate-based ILs (molar fraction of CO2 around 0.25) and more than ten times the capacity of physical ionic liquids (molar fraction 0.02). Consequently, SILs are found to be efficient CO2 absorbents operating at atmospheric pressure.HighlightsComparison of ionic liquid systems acting as chemical vs. physical solvents in practical terms. ► Recycling and reuse issues of ionic liquids in carbon dioxide capture. ► Introduction of new types of switchable ionic liquids. ► Studying the capture-release cycle behavior of the aforementioned ionic liquids. ► In essence, we have focused on engineering aspects.
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| 4. |
- Privalova, Elena I, et al.
(författare)
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Amine Solutions for Biogas Upgrading : Ideal versus Non-Ideal Absorption Isotherms
- 2013
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Ingår i: Chemical Engineering & Technology. - : Wiley-VCH Verlagsgesellschaft. - 0930-7516 .- 1521-4125. ; 36:5, s. 740-748
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Tidskriftsartikel (refereegranskat)abstract
- Amine solutions were applied in carbon dioxide removal from a model mixture of biogas, carried out in a loop reactor system. In addition, the effect of CO2 absorptio acceleration in the presence of piperazine was confirmed and quantified, relating the obtained CO2 loading with the piperazine concentration. Further, the interactions of CO2 and water in aqueous amine solutions were discussed. The obtained acid gas loadings were accurately described taking into account the effect of the dissolved CO2 on the equilibrium constant. A logarithmic absorption isotherm that follows from such considerations and a saturation-type isotherm were compared. In describing the experimental data, advantages and disadvantages of both approaches are discussed.
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| 5. |
- Privalova, E, et al.
(författare)
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Ionic liquids versus amine solutions in biogas upgrading : the level of volatile organic compounds
- 2013
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Ingår i: Biofuels. - : future science ltd. - 1759-7269 .- 1759-7277. ; 4:3, s. 295-311
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Tidskriftsartikel (refereegranskat)abstract
- Background: This article provides information related to the occurrence of volatile organic compounds before and after biogas purification, by means of both aqueous amine solutions and ionic liquids. Results & discussion: Encouraging results were obtained. Under the experimental conditions, 1-butyl-3-methylimidazolium acetate ionic liquid appeared to perform at least two-times better than aqueous amines solutions, since it captured 65 wt% of the identified volatile organic compounds, while aqueous amine solutions retained around 35 wt% only. However, in the case of octamethylcyclotetrasiloxane and dichlorobenzene, aqueous amine solutions rendered better purification performance and diminished the concentration of aforementioned compounds by a factor of five and ten, respectively. Conclusion: This paper sheds new light on ionic liquids as potential separation sorbents and contributes to the understanding of the complex science of biogas upgrading and utilization of renewable energy resources.
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| 6. |
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| 8. |
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| 9. |
- Tokarev, A V, et al.
(författare)
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The role of bio-ethanol in aqueous phase reforming to sustainable hydrogen
- 2010
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Ingår i: International journal of hydrogen energy. - : Elsevier Ltd. - 0360-3199 .- 1879-3487. ; 35:22, s. 12642-9
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Tidskriftsartikel (refereegranskat)abstract
- Aqueous Phase Reforming (APR) has during the recent years emerged as a potent, alternative means of processing raw materials of biological origin to component suitable as chemicals and fuel components. In contrary to e.g. steam reforming, aqueous phase reforming bares the promise of lower temperatures in processing which gives rise to potential of reduced energy consumption in the upgrading process itself.Aqueous phase reforming was studied over Pt/Al2O3 at 225 °C. Stable catalyst performance and high selectivity was observed. Upon a comparison of two ‘bio-alcohols’, bio-ethanol and Sorbitol (a sugar alcohol), the latter one is a better feedstock from overall energy utilization viewpoint but the use of it results in a broad range of products. Interestingly, in the case of sorbitol–ethanol mixtures, an improvement in the hydrogen yield was observed.
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| 10. |
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