| 1. |
- de Leeuw, N.H., et al.
(författare)
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Modeling the competitive adsorption of water and methanoic acid on calcite and fluorite surfaces
- 1998
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 14:20, s. 5900-5906
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Tidskriftsartikel (refereegranskat)abstract
- Atomistic simulation techniques were used to investigate the interaction between the minerals calcite and fluorite with water and methanoic acid. The relative adsorption energies suggest that methanoic acid preferentially adsorbs onto fluorite surfaces, while adsorption of water is energetically preferred over methanoic acid on the calcite cleavage plane in agreement with experiment. The coverage and configuration of adsorbed methanoic acid on the surfaces depends largely on lattice spacing between the cations, and bridging between surface calcium atoms is highly favored. These findings have given an insight into interactions at the atomic level which indicate that modeling techniques should be capable of predicting adsorption behavior and designing collector molecules, which is of central importance to the mineral processing technique of flotation
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| 2. |
- Natarajan, E, et al.
(författare)
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Experimental determination of bed agglomeration tendencies of some common agricultural residues in fluidized bed combustion and gasification
- 1998
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Ingår i: Biomass and Bioenergy. - 0961-9534 .- 1873-2909. ; 15:2, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- Ever increasing energy demand and the polluting nature of existing fossil fuel energy sources demonstrate the need for other non-polluting and renewable sources of energy. The agricultural residues available in abundance in many countries can be used for power generation. The fluidized bed technology seems to be suitable for converting a wide range of agricultural residues into energy, due to its inherent advantages of fuel flexibility, low operating temperature and isothermal operating condition. The major ash-related problem encountered in fluidized beds is bed agglomeration which, in the worst case, may result in total defluidization and unscheduled downtime. The initial agglomeration temperature for some common tropical agricultural residues were experimentally determined by using a newly developed method based on the controlled fluidized bed agglomeration test. The agricultural residues chosen for the study were rice husk, bagasse, cane trash and olive flesh. The results showed that the initial agglomeration temperatures were less than the initial deformation temperature predicted by the ASTM standard ash fusion tests for all fuels considered. The initial agglomeration temperatures of rice husk and bagasse were more than 1000°C. The agglomeration of cane trash and olive flesh was encountered at relatively low temperatures and their initial agglomeration temperatures in gasification were lower than those in combustion with both bed materials. The use of lime as bed material instead of quartz improved the agglomeration temperature of cane trash and olive flesh in combustion and decreased the same in gasification. The results indicate that rice husk and bagasse can be used in the fluidized bed for energy generation since their agglomeration temperatures are sufficiently high.
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