Water-use systems impact nearly all plant operations either directly or indirectly. The need for optimization emanates from high water use demands, water utility cost or strict environmental regulations.
Industrial water demand may increase for reasons such as strict product specification requiring more washing , new or improved units requiring more water or most commonly failing equipments such as leaking heat exchangers and clogged tubes can lead to more water needs( cooling for eg.).As the demand for water increases the cost of water use increases proportionally.
Reduce need
Blowdown streams. Recirculating-cooling-tower and boiler-feed streams build up dissolved solids, especially calcium and magnesium compounds, silica and other contaminants that are relatively insoluble in water.
Water-treatment regeneration streams. Ion exchange media (salt brine for softeners, acid and bases for deionizers) used to remove both suspended and dissolved solids generally require regeneration.
Condensate. By returning condensate to the boiler for use as feed water, facilities reduce the makeup source demands and lower regeneration flows because condensate does not typically require water treatment.
Separate clean streams
Many non-process streams are eligible for direct discharge depending on the governing discharge permit requirements. These are steam blow down; Non-contact cooling water and condensate; Cooling tower blow down; Condensate and cooling water from heating/ventilating/ air-conditioning units
Recycle
The reuse of treated effluent does not reduce the total flow rate of wastewater requiring treatment and thus, is generally less desirable than the direct reuse of clean wastewater. One of the more-common unit operations for wastewater treatment at process plants is biotreatment, which is effective for decreasing soluble organic concentrations.
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