Washing process equipment

Safe handling practices are essential at all stages of production, from the laboratory to the manufacturing operations. The safety committee should inspect and advise on processing equipment and be responsible for providing personal protection, eye wash fountains, safety showers, etc. 

F1G. 18-123 Cake discharge and medium washing on an EIMCO helt filter. (EIMCO Process Equipment Co.)... 

Over 22.7 million kg (50 million lb) of zinc sulfate are used annually in the U.S. for the manufacture of approximately 454 million kg (one billion lb) of viscose rayon. Zinc is used as a regeneration retardant in the acid spinning bath. Because it is not consumed in any of the viscose reactions, these 22.7 million kg (50 million lb) of zinc represent process losses, through dragout by the filaments to the subsequent wash streams, filter backwashing, splashes, leaks, and the washing of equipment.14... 

General-purpose water The application includes washing and sanitizing raw materials, processing equipment, plant facility, and ancillary equipment. The water must be free of contaminants since the water contacts food directly. 

Wash and rinse water Sorting, packing, cutting, and further processing equipment Ice... 

The performance of many process equipment encountered in crystallization practice is often profoundly affected by the flow properties of the liquid media. Heat transfer, for example, may be severely impeded in thick sluggish liquors or magmas crystallization may occur only with difficulty, and filtration and washing of crystalline product may be impaired (Mullin, 1961). Since viscosity is a function of temperature the viscosity at the average temperature of crystallization is considered. The viscosity of the solvent can be estimated using the following group contribution model (ICAS, 2003)... 

The process equipment consists mainly of two extraction columns with pulsating trays and four distillation columns according to Fig. 10.4 [7]. The feed, with a high content of aromatics, is pumped to the middle of the first extraction column where the aromatics are extracted with the solvent SI (tetraethylene glycol). In the lower part, the extracted aromatics are washed with S2 (dodecane). The outgoing raffinate phase R1 (containing aliphatics,... 

In the washing process, acids and nitrophenols are removed from the crude MNB by means of an alkaline wash. Condensate from the acid concentrator may be used as wash water. The washing section of the plant employs specially designed equipment for space saving, minimum use of wash water and elimination of circulation pumps. 

In the newest plants, the sealed mixing chamber would be directly connected to the feed throat of the thermal processing equipment before it is opened. When the vessel is emptied, it is again closed and sent to a special equipment wash bay for cleaning. This enclosed system virtually eliminates dust emissions throughout the thermal encapsulation process. 

It has been found that glycerine left inside processing vessels, especially carbon columns, can degrade and develop hard-to-remove odors. Therefore, process equipment should be cleaned completely after shutdown, and carbon columns blown down with air and washed with water. Also, fresh carbon can sometimes contain odor-causing impurities. The carbon can be washed with distilled glycerine that can be subsequently redistilled or sold as a lower grade. 

Membranes are used in the pulp and paper industry in a variety of applications in particular for the purification and recovery of water, and for the recovery of raw materials or energy. The pulp and paper manufacturing process requires enormous amount of water to transport the raw materials, to dissolve impurities, to seal various process equipment, to cool and heat, to wash and clean process equipment, and to generate necessary environment for the formation of the hydrogen bonding network between fibers and fillers, which is the basic mechanism of paper formation. Thus, water and its quality are essential issues in the production of pulp and paper. 

The ability to separate a mixture of two liquid phases is critical to the successful operatiou of mauy chemical aud petrochemical processes. Besides its obvious importauce to liquid-liquid extractiou aud washing operations, liquid-liquid phase separation can be a critical factor in other operations including two-liquid-phase reaction, azeotropic distillation, and industrial wastewater treatment. Sometimes the required phase separation can be accomplished within the main process equipment, such as in using an extraction column or a batch-wise, stirred-tank reactor but in many cases a stand-alone separator is used. These include many types of gravity decanters, filter-type coalescers, coalescers filled with granular media, centrifuges, and hydrocyclones. 

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