Cleaning solvents

Film pressure is often measured directly by means of a film balance. The principle of the method involves the direct measurement of the horizontal force on a float separating the film from clean solvent surface. The film balance has been considerably refined since the crude model used by Langmuir and in many... 

There are problems in use of the frit nebulizer. Memory effects tend to be severe, and each sample needs to be followed by several wash-outs with clean solvent before the pores of the frit become free of residual sample. Biological samples frequently contain detergent-like materials, and... 

Cleaning formulations Cleaning products Cleaning solvents Cleanness Clean rooms... 

Dry bead process Dry-cell batteries Dry chemistry Dry-cleaning Dry cleaning fastness Dry-cleaning fluid Dry-cleaning solvent Dryers... 

Another quaHty control problem of multipurpose plants is the clean out for a product change. A test for residual cleaning solvents in the ppm level is a necessity. The best vaHdation of the cleaning process is to develop an analytical method that is able to find the previous product in the new product at a level of not more than 1 ppm. Tests should be mn on at least the first three batches. 

Other Properties. With respect to dry-cleanabiUty, vinyl-coated fabrics are worse than the others due to dissolution of plasticizer in the cleaning solvent. Only man-made leathers with poromeric nonwoven can be skived, spHt, and cut in the same manner as leather. 

The main uses of petroleum naphtha fall into the general areas of solvents (diluents) for paints, etc, dry-cleaning solvents, solvents for cutback asphalt, solvents in mbber industry, and solvents for industrial extraction processes. Turpentine, the older, more conventional solvent for paints, has been almost completely replaced by the cheaper and more abundant petroleum naphtha. 

For accurate and precise measurement the glass capillary must be clean. The viscometer must be cleaned thoroughly after each series of operations. Samples being tested and cleaning solvents should be filtered to remove particles that can clog the capillary. 

AH volatile organic solvents are toxic to some degree. Excessive vapor inhalation of the volatile chloriaated solveats, and the central nervous system depression that results, is the greatest hazard for iadustrial use of these solvents. Proper protective equipment and operating procedures permit safe use of solvents such as methylene chloride, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene ia both cold and hot metal-cleaning operations. The toxicity of a solvent cannot be predicted from its chlorine content or chemical stmcture. For example, 1,1,1-trichloroethane is one of the least toxic metal-cleaning solvents and has a recommended threshold limit value (TLV) of 350 ppm. However, the 1,1,2-trichloroethane isomer is one of the more toxic chloriaated hydrocarboas, with a TLV of only 10 ppm. 

G. W. Bradley and co-workers, "Investigation of Ammonium Citrate Cleaning Solvents," Proceedings of the 36th International Water Conference, Pittsburgh, Pa., Nov. 4—6, 1975. 

Other apphcations for the diesters of the diacids are known. Du Font s Di-basic Ester (DBE) is an effective industrial cleaning solvent and paint stripper. DBE is marketed as an environmentally superior substitute to the chlorinated solvents (105). 

Pan. Indirect type, batch operation Atmospheric or vacuum. Suitable for small batches. Easily cleaned. Solvents can be recovered. Material agitated while dried See comments under Liquids See comments under Liquids See comments under Liquids Suitable for small batches. Easily cleaned. Material is agitated during drying, causing some degradation Not applicable Not appbcable Not appbcable... 

Use chemical interaction matrices to identify potential incompatibilities between combinations of materials (not just binary reactions) and interactions with cleaning solvents, heat transfer fluids and other utilities, equipment lubricants, scrubbing media, materials of construction, etc. Implement management of change procedures for changes in design, operation, equipment and chemistry. 

Chemical reaction due to Develop written procedures to clean and equipment not being verify reactor readiness properly cleaned/ drained. jn piement checklist verification from previous run. Possi- bility of unwanted reac- cleaning solvent tion or insufficient desired reaction. CCPS G-15 CCPS G-22 CCPS G-29... 

A reaction vessel explosion at BASF s resins plant in Cincinnati (July 19, 1990) killed one and injured 71. The BASF facility manufactures acrylic, alkyd, epoxy, and phenol-formaldehyde resins used as can and paper-cup liner coatings. The explosion occurred when a flammable solvent used to clean a reaction vessel vented into the plant and ignited. The cleaning solvent that was not properly vented to a condenser and separator, blew a pressure seal, and fdled the 80-year-old building with a white vapor cloud. 

CFCs have been widely used as cleaning solvents, as they are nonflammable and their toxicity is low. Now, flammable solvents are coming back into favor. A news item from a manufacturer described "a new ozone-friendly cleaning process for the electronics industry, which "uses a unique hydrocarbon-alcohol formulation. It did not remind readers that the mixture is flammable and that they should check that their equipment and procedures are suitable. 

Covered by the exemption are drilling fluids, cuttings, completion fluids, and rigwash. Not covered by the exemption are motor and chain oil wastes, thread cleaning solvents, painting waste, trash and unused completion fluids. 

Before hydraulic lines or fittings are disconnected, the affected area should be cleaned with an approved dry-cleaning solvent. 

After the parts have been cleaned in dry-cleaning solvent, they should be dried thoroughly with clean, low-lint cloths and lubricated with the recommended preservative or hydraulic liquid before assembly. Note Only clean, low-lint type 11 or 1 cloths as appropriate should be used to wipe or dry component parts. 

Also, corrosion may continue to take place under deposits, or the rate of cleaning may be so slow that some level of damage occurs during the process, either overheating or possibly corrosion as a result of the cleaning solvent. 

Offline cleaning can, and should, be entirely successful, with the simplest methods requiring, say, a 10 or 15% inhibited hydrochloric (muriatic) acid solution that is allowed to soak for some hours before neutralization, flushing, and refilling. Where the waterside deposit analysis reveals complex scales, however, it may be necessary to employ several different cleaning solvents. These solvents are added in a multistep process. 

Additionally, it is important to know the true volume of the boiler and to ensure that adequate cleaning solvent and other chemicals are made available before the work begins. For most cleaning programs,... 

Hydrochloric acid (muriatic acid, HC1). Supplied in concentrated form at approximately 32 to 37% w/v HC1 in water. This is the standard acidic cleaning solvent, but it is often very corrosive and the spent solution needs considerable rinsing. Very aggressive Typically, clean at 5 to 20% v/v product/water at 150 to 180 °F (66-82 °C), but up to only 120 °F (49 °C) for cast iron and up to 140 °F for marstenitic SS (60 °C). 

Most scales contain several of these salts, together with iron and some copper. Therefore, the choice of cleaning solvent or mixture must take account of these different constituents. (Refer to the previous sections for more details of many of these solvents.)... 

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