Application of wasted sea-shell to desulfurizer in fluidized bed coal combustion
Almost all wasted seashells consist of CaCo{sub 3}, and are similar to limestone. It would be proposed that the seashell could be applied as a desulfurizer. In this study, desulfurization characteristics of the seashell are fundamentally studied by using a thermobalance and a bubbling fluidized coal combustor with comparing the results obtained by limestone as a reference. Under the constant calcination temperature, the desulfurization efficiency for the seashells attains more than about 70% after the desulfurization period of 30 h. For the limestones, on the other hand, the desulfurization efficiency becomes only 38%. Under practical conditions of fluidized bed coal combustion, the desulfurization efficiency for the seashells also indicates higher value than that for the limestones. The desulfurization efficiency depends on the pore size distribution of CaO rather than its specific surface area. The mean pore size of the calcined seashell is about 10 times as large as that of the calcined limestones. from Scanning Electro-Microscope (SEM) photos of the surface of CaCO{sub 3}, CaO and the sulfurized particles of the seashells the large pores can be observed. In measuring cross-sectional distribution of sulfur inside the particles by using an Energy Dispersed X-ray (EDX) system, the sulfur in the sulfurized particle of limestone is only trapped near the particle surface. For the seashells, whereas, the sulfur is distributed over the whole body of particle. Desulfurization efficiency for the limestone, into which some alkali metal compounds are added, increases with increasing the concentration of alkali metal compounds added. In order of increasing effect the key elemental species to enhance the desulfurization activities are Cl, Na and K. Alkali metal compounds can enhance the desulfurization activities, due to solution of CaO in molten NaCl. This is one of the reasons why the desulfurization efficiency for the seashells improves.
- Research Organization:
- Toyohashi Univ. of Technology, Tempaku (JP)
- OSTI ID:
- 20006764
- Report Number(s):
- CONF-990534-; TRN: IM200008%%371
- Resource Relation:
- Conference: 15th International Conference on Fluidized Bed Combustion, Savannah, GA (US), 05/16/1999--05/19/1999; Other Information: 1 CD-ROM. Operating system required: Windows 3.x; Windows 95/98/NT; Macintosh, Power Macintosh; UNIX. All systems need 2X CD-ROM drive.; PBD: 1999; Related Information: In: Proceedings of the 15th national conference on fluidized bed combustion, by Reuther, R.B. [ed.], [1800] pages.
- Country of Publication:
- United States
- Language:
- English
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