| 1. |
- Naderi, Fereshteh, et al.
(författare)
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Multiconfigurational Study of the Electronic Structure of Negatively Charged Fullerens
- 2017
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Ingår i: Journal of Chemistry and Chemical Engineering. - : David Publishing Company. - 1934-7375 .- 1934-7383. ; 11, s. 30-30
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Tidskriftsartikel (refereegranskat)abstract
- Multiconfigurational second order perturbation theory was employed in order to describe the ground and excited states of C_60^(-n). Different choices of the active spaces are discussed and the possibility to apply multiconfigurational theory to study C_120 is investigated. The calculations were performed for all possible spin states (for selected charge) and show the preference of low spin state. The energy difference between two C_60^(-3) and pairs C_60^(-1)- C_60^(-5) and C_60^(-2)- C_60^(-4) shows that the probability to create a charge alternation in fullerides is small.
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| 2. |
- Anukam, Anthony, et al.
(författare)
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Assessment of the Influence of Torrefied Biomass Physical Characteristics, Design and Operating Variables on Gasification Efficiency
- 2016
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Ingår i: Journal of Chemistry and Chemical Engineering. - : David Publishing Company. - 1934-7375 .- 1934-7383. ; :10, s. 283-292
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Tidskriftsartikel (refereegranskat)abstract
- Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physical properties of torrefied bagasse and the influence of gasifier design and operating variables were investigated in a computer simulated downdraft gasification system. Results obtained from the study indicated an interrelationship between feedstock characteristics, especially with regard to feed size, design variables such as throat angle and throat diameter as well as gasifier operating conditions such as temperature of input air and feed input. These variables influenced the efficiency of the gasification process of sugarcane bagasse because of increased enhancement of combustion zone reactions, which liberated huge amount of heat that led to a rise in the temperature of the gasification process. This condition also created increased tar cracking within the gasification system, contributing to reduction in the overall yield of tar.
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| 3. |
- Granström, Karin, 1974-, et al.
(författare)
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Pre-Treatment To Enhance Biogas Yield from Pulp and Paper Mill Sludge
- 2014
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Ingår i: Journal of Chemistry and Chemical Engineering. - Libertyvill IL : David Publishing Company. - 1934-7375 .- 1934-7383. ; :8, s. 825-833
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat (70 oC or 140 oC) combined with either acid (pH 2 or pH 4) or base (pH 9 or pH 11, obtained with Ca(OH)2 or NaOH). Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70 oC did not differ from the untreated sludge, but thermal pre-treatment at 140 oC had a positive effect. Within the 70 oC thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca(OH)2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 oC thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca(OH)2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70 oC showed no effect, whereas, pre-treatment at 140 oC improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.
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| 4. |
- Nurni, Viswanathan, et al.
(författare)
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Model for reduction of iron oxide pellet with a C-O-H-N gas mixture considering water gas shift equilibrium in the gas while it diffuses through the product layer
- 2013
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Ingår i: Journal of Chemistry and Chemical Engineering. - 1934-7375 .- 1934-7383. ; :7, s. 666-670
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Tidskriftsartikel (refereegranskat)abstract
- In metallurgical processes, more and more usage of hydrocarbons is encouraged to bring down the carbon emissions. In this regard, numerous investigations on reduction of oxides by C-O-H-N gas mixture have been reported. Attempts to simulate these reduction processes using shrinking core model, one of the common models used for such studies, have under predicted the reduction rates. This may be owing to the fact that the homogeneous reaction in the gas phase is not being considered. If the reaction temperatures are above 1,000 K, generally so for many reduction processes, the homogeneous gas reaction rates are expected to be high enough that local equilibrium in the gas phase can be assumed. In the present study, reduction of wustite in a C-O-H-N gas mixture has been modeled using shrinking core model considering the water gas shift equilibrium in the gas while it diffuses through the product layer.
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