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Show 5.9.4 STORAGE In order to design the storage system to permit a feed of uniform mixture, proper mixing is important. Experience has shown that layering will occur in large tanks, especially where wastes enter the storage tank from different sources.(5) Mixing is effective with internal mixers, external recycle pumps, air or steam spargers, etc. The materials of construction of all components - tanks, pumps, mixers and piping - will be based on the chemical composition, viscosity, corrosivity and solids content of the waste. Inert solids should be filtered out rather than pumped into the high temperature reaction zone of the incinerator. Solids containing organics must be considered part of the load for incineration and handled accordingly. TRANSPORT High viscosity materials and liquids/solids mixtures present a problem in the material transport portion of the plant. Progressive cavity pumps have been used successfully, providing the materials of the rotor and the stator are selected properly. Gear pumps have been the workhorse for most lower viscosity materials (equivalent to #6 fuel oil and below). However, in this case the combination of viscosity and speed are critical for long life, low maintenance operation. In plants where a variety of wastes have to be pumped into the incineration system, the operators must select the proper pumps to use with each waste, as well as liquid temperatures, pump speed and discharge pressure of the waste to prevent erosion of the pumping equipment. |