PROPOSING THE MOST EFFICIENT AND ENVIRONMENTAL SAFE HYDROCYCLONE TO DEPURATE BALLAST WATER FROM SHIP HULLS
Special Symposium - Environmental Protection & Sustainability
Environmental Protection & Sustainability (EPS - Poster)
Keywords: Ballast Water Depuration, SL Separation, Hydrocyclones, Life Cycle Assesment
Lucía F. Martínez* lusifm@gmail.com
Antonio G. Lavín agl@uniovi.es
Manuel M. Mahamud mahamud@uniovi.es
Julio L. Bueno jlbueno@uniovi.es
Department of Chemical Engineering and Environmental Technology. University of Oviedo. c/ Julián Clavería 8. 33006 Oviedo, Spain.
*Corresponding author. Phone: 34985102997 Fax: 34985103434
Oceans are exposed to several environmental threats such as overexploitation of living marine resources and physical alteration/destruction of marine habitat and introduction of invasive marine species into new environments by ships’ ballast water. When marine species are introduced in new environments and living conditions are favourable to their replication, the may become invasive competing with native species and even causing severe human health, economic and/or ecological impacts in their host environments. In order to prevent such kind of pollution, there exist new maritime standards which consist of primary treatment that allows the elimination of suspended solids and secondary treatment that exterminates microorganisms.
In our work we have designed a pilot plant integrated by a set of separative and reactive operations according to Rietema criterion we have designed and built a set of several hydrocyclones that works as primary treatment to eliminate solid particles from water and thus, increasing removal efficiency in a subsequent secondary treatment. In order to test hydrocyclone performance under different operative conditions, different geometrical characteristics have been modified. Showing that slight modifications of any of these features as optimization of the vortex finder length ratio might severely affect the separation efficiency. Without any vortex finder, the “short-circuit” generated in the upper part of the hydrocyclone avoids a clear separation. In the same way, when the depth of the vortex finder is excessive, a substantial decrease on efficiency may be observed due to the swirls generated in the bottom of the hydrocyclone. Although the less efficient conditions take place when the vortex-finder depth is near to the juncture between the cylindrical and the conical part, due to the synergy of two phenomena: the change of trajectory by means of entering in the conical part and the turbulence associated to the vortex finder itself.
An integral evaluation of this system was carried out in order to optimize environmentally by means of a LCA protocol. It can be supposed that the environmental cost is null or very low due to the fact that the system analysed is used to avoid ocean pollution. However, if a further analysis is carried out it can be seen that even this equipment through the different stages in their life (raw materials, processing, usage, transport and disposal) could cause some impacts. Here is addressed which hydrocyclone geometry must be chosen depending on the operation conditions; showing that the limitating steps are material quantity and energy requirement.
See the full pdf manuscript of the abstract.
Presented Monday 17, 13:30 to 15:00, in session Environmental Protection & Sustainability (EPS - Poster) S-7P.
