| 1. |
- Abdelaziz, Omar Y., et al.
(författare)
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Novel process technologies for conversion of carbon dioxide from industrial flue gas streams into methanol
- 2017
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Ingår i: Journal of CO2 Utilization. - : Elsevier BV. - 2212-9820. ; 21, s. 52-63
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Tidskriftsartikel (refereegranskat)abstract
- This research aims to develop efficient process technologies that are capable of converting/utilising CO2 streams into energy-rich liquid products (fuels). This would result in better solutions with near-zero-carbon-emissions level. From an energetic and economic point of view, methanol synthesis from CO2 is a competitive alternate to methanol production from biomass. Our work considers the CO2 balance for the technologies proposed, taking into account all CO2 flows from/to the environment. Flue gas CO2 streams released from electric power stations, steel industry, petroleum industry, and cement industry are good candidates for the developed technologies. Three new processes are developed and modelled for converting CO2 streams into liquid methanol. The total cost of equipment and utility for all process scenarios are evaluated and compared. The energy targets as well as the CO2 emissions (balance) are determined. Heat integration is performed on the best selected process technology. The case study employed for the present work is a power station plant burning natural gas for electricity production with a capacity of 112 MW, releasing 328 t/h flue gases to the atmosphere, of which CO2 gas accounts for 14%; hydrogen required for CO2 conversion comes from the chlor-alkali industry. The optimum process technology reached in this contribution results in methanol production of 0.625 t-per-tonne of CO2 waste gas supply, leading to an annual production of 222,507 tons methanol with a profit of 56.55 M$/y. Thus, the CO2 release to the environment is cut by about 62%.
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| 2. |
- Ashour, Radwa M., et al.
(författare)
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Selective separation of rare earth ions from aqueous solution using functionalized magnetite nanoparticles : kinetic and thermodynamic studies
- 2017
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 327, s. 286-296
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Tidskriftsartikel (refereegranskat)abstract
- Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functionalized ligands on the adsorption efficiency and selective adsorption of La3+, Nd3+, Gd3+ and Y3+ from aqueous solution using Magnetite (Fe3O4) nanoparticles (NPs) functionalized with citric acid (CA@Fe3O4 NPs) or L-cysteine (Cys@Fe3O4 NPs). The microstructure, thermal behavior and surface functionalization of the synthesized nanoparticles were studied. The general adsorption capacity of Cys@Fe3O4 NPs was found to be high (98 mg g−1) in comparison to CA@Fe3O4 NPs (52 mg g−1) at neutral pH 7.0. The adsorption kinetic studies revealed that the adsorption of RE3+ ions follows a pseudo second-order model and the adsorption equilibrium data fits well to the Langmuir isotherm. Thermodynamic studies imply that the adsorption process was endothermic and spontaneous in nature. Controlled desorption within 30 min of the adsorbed RE3+ ions from both Cys@Fe3O4 NPs and CA@Fe3O4 NPs was achieved with 0.5 M HNO3. Furthermore, Cys@Fe3O4 NPs exhibited a higher separation factor (SF) in the separation of Gd3+/La3+, Gd3+/Nd3+, Gd3+/Y3+ ions compared to CA@Fe3O4 NPs.
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| 3. |
- Kamel, Dina A., et al.
(författare)
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Temperature driving force (TDF) curves for heat exchanger network retrofit - A case study and implications
- 2017
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 123, s. 283-295
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Tidskriftsartikel (refereegranskat)abstract
- In the present contribution, concepts supporting a new analysis method to retrofit heat exchanger networks (HENs) are presented. The new graphical representation appears to be simple to use and needs no simulation tools or software packages to perform the retrofit calculations and is found valuable for conceptual applications. The temperature driving force new representation (TDF) is accordingly applied to an existing HEN in an Egyptian refinery to boost its energy efficiency and generate cost-effective opportunities. This refinery is the most recent unit installed in Egypt as it has been built in 1994. Since this refinery is very modern, its energy consumption exceeds the benchmark by only 21.5% which is relatively very low compared to its counterparts worldwide. The graphical revamping in application applied on the HEN shows savings of approximately 10.5% in the energy demand with minor structural modifications, achieving some 60% of the potential energy savings with respect to Pinch Analysis benchmarks. The modified preheat train only exceeds the benchmark by 8.8%. Implications and advantages of the new developed approach are also discussed, highlighting the merits of the proposed method.
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| 4. |
- Ali, Dalia A., et al.
(författare)
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Co-gasification of coal and biomass wastes in an entrained flow gasifier: Modelling, simulation and integration opportunities
- 2017
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Ingår i: Journal of Natural Gas Science and Engineering. - : Elsevier BV. - 1875-5100. ; 37, s. 126-137
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Tidskriftsartikel (refereegranskat)abstract
- Gasification processes convert carbon-containing material into syngas through chemical reactions in the presence of gasifying agents such as air, oxygen, and steam. Syngas mixtures produced from such processes consist mainly of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), and methane (CH4); this gas can be directly utilised as a fuel to produce electricity or steam. Besides, it is regarded as a basic feedstock within the petrochemical and conventional refining industries, producing various useful products like methanol, hydrogen, ammonia, and acetic acid. In this work, a rigorous process model is developed to simulate the co-gasification of coal-biomass blends through an entrained flow gasifier. The proposed model is tested originally for American coal. The model validation is made against literature data and results show good agreement with these practical data, providing a robust basis for integration and retrofitting applications. Effects of critical parameters, comprising gasification temperature, steam/O2 ratio, and feedstock variability on the syngas composition and gasifier efficiency are studied. The developed model is further applied in a project to revamp an existing Egyptian natural gas-based power plant, replacing its standard fuel with coal-rice straw blends. The revamping project integrates the existing plant with a gasification unit burning a blend of coal and rice straw to replace the conventional fuel used. The feedstock used constitutes a dry Egyptian coal and a coal-rice straw blend (10 wt% rice straw), gathered locally. Different blending scenarios are investigated and the best performance is achieved with coal to rice straw ratio of 90:10 on weight basis, attaining 85.7% cold gas efficiency and significant economic savings. Results showed that the total annualised cost of the revamped process decreased by 52.7% compared with a newly built integrated gasification combined cycle (IGCC) unit.
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| 5. |
- Ashour, Radwa M., et al.
(författare)
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Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets
- 2017
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Ingår i: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 35:2, s. 91-103
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Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO3 acid (0.1 M) after a short contact time (15 min).
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