Equipment cleaning selection

This chapter deals with the essential factors in the selection of systems and equipment during the design stage principles of controls, noise-reduction systems, and problems such as erosion, corrosion, maintenance and equipment cleaning, etc. 

As shown above, similar products can be validated together on the same equipment by selecting representative products for the validation procedure ( bracketing ). The Cleaning Validation procedures must be carried out according to the critical parameters of these products. 

There are four types of equipment cleaning preoperational, chemical, mechanical, and on-line. These must he evaluated for each job in order to select the most cost-effective. To make a sound evaluation, the deposit to be removed should be thoroughly characterized. 

Toxicity. Toxicity has no influence on the actual size reduction, but equipment is often selected for ease of product containment or safe cleaning. 

G-7. Stern, Air Follution, 3d ed., vols. 3-5, Academic, Orlando, FL, 1976-77. G-8. Strauss, Industtial Gas Cleaning, 2d ed., Pergamon, New York, 1975. G-9. Theodore and Biionicore, Air Follution Control Equipment Selection, Design, Operation and Maintenance, Prentice Hall, Englewood Cliffs, NJ, 1982. 

Implicit in cake filtration is the removal and handling of solids, since the cake is usually relatively dry and compacted. C es can be sticky and difficult to handle therefore, the ability of a filter to discharge the cake cleanly is an important equipment-selection criterion. 

Pretreatment For most membrane applications, particularly for RO and NF, pretreatment of the feed is essential. If pretreatment is inadequate, success will be transient. For most applications, pretreatment is location specific. Well water is easier to treat than surface water and that is particularly true for sea wells. A reducing (anaerobic) environment is preferred. If heavy metals are present in the feed even in small amounts, they may catalyze membrane degradation. If surface sources are treated, chlorination followed by thorough dechlorination is required for high-performance membranes [Riley in Baker et al., op. cit., p. 5-29]. It is normal to adjust pH and add antisealants to prevent deposition of carbonates and siillates on the membrane. Iron can be a major problem, and equipment selection to avoid iron contamination is required. Freshly precipitated iron oxide fouls membranes and reqiiires an expensive cleaning procedure to remove. Humic acid is another foulant, and if it is present, conventional flocculation and filtration are normally used to remove it. The same treatment is appropriate for other colloidal materials. Ultrafiltration or microfiltration are excellent pretreatments, but in general they are... 

Both parties need to identify responsibilities for choosing the right equipment for the process, preparing equipment for the process, and decontaminating equipment. Consider whether chemical and process hazards have been addressed in the selection, preparation, and decontamination of equipment. Examine the need to contractually address containment and disposal of residual process fluids and decontamination materials. If food products or pharmaceuticals are involved, cleaning methods may also be an issue to address in the contract. 

The elements of a PM plan include periodic inspection, cleaning, and service as warranted, adjustment and calibration of control system components, maintenance equipment and replacement parts that are of good quality and properly selected for the intended function. Critical HVAC system components that require PM in order to maintain comfort and deliver adequate ventilation air include a outdoor air intake opening, damper controls, air filters, drip pans, cooling and heating coils, fan belts, humidification equipment and controls, distribution systems, exhaust fans. 

The aim of this section is to introduce the fundamentals of incineration, adsorption, absorption, condensation, and biological treatment in order to provide a basic knowledge for the selection of suitable equipment. The waste gas characteristics that play a major role in the selection of gas-cleaning equipment are also considered. A detailed presentation of the theory of combustion, adsorption, absorption, condensation, or biological decomposition required for a complete understanding of the subject is not covered in this section (the theory can be found in the handbooks such as Perry s Chemical Engineers Handbook). 

The first essential step in the design of a fume control system and selection of gas-cleaning equipment is the characterization of the fume emission source. Design procedures which can be used for new and existing industrial plants follow. The characterization of fume emission sources includes parameters such as plume flow rates (mVs), plume geometry (m), source heat flux (J/s), physical and chemical characteristics of particulates, fume loadings (mg/m ), etc. 

Such requirements could deal with the selection and performance of gas cleaning equipment, and with the design of the duct systems (including stacks). 

Of all the requirements that have to be fulfilled by a manufacturer, starting with responsibilities and reporting relationships, warehousing practices, service contract policies, airhandUng equipment, etc., only a few of those will be touched upon here that directly relate to the analytical laboratory. Key phrases are underlined or are in italics Acceptance Criteria, Accuracy, Baseline, Calibration, Concentration range. Control samples. Data Clean-Up, Deviation, Error propagation. Error recovery. Interference, Linearity, Noise, Numerical artifact. Precision, Recovery, Reliability, Repeatability, Reproducibility, Ruggedness, Selectivity, Specifications, System Suitability, Validation. 

Temperature control Adequately sized pressure relief Elimination of contaminants, including metallic residues, from process streams and equipment Selection of materials of construction compatible with the chemicaKs) in use, properly cleaned and passivated Elimination of ingress of reactive chemicals, e.g. water, air Date labelling and inventory control in storage Cleaning and inspection of reusable containers, tankers etc. before refilling ... 

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