Testing for Foam

The bottle shake test. A clean bottle is filled with solution from the system. The bottle is left open for some time to allow all the dissolved gas to escape. A cap is put on, and the bottle is vigorously shaken up md down, then set on a table. The foam height and the time teiken for the foam to settle back to the liquid level are recorded. If it takes more than 5 s to settle, foaming is indicated. This test was successfully used in amine absorbers (22). This method is simple, but may often fail to detect foaming. 

Dispersing air or nitrogen through a solution seunple in a small 

An apparatus in which gas is dispersed through a solution sample (Fig. 14.12a,6). The gas is usually dispersed via a fritted filter to give good dispersion. Details are described elsewhere (135, 373). This test, at least in principle, may suffer from the same problem as (1) above, but the experience reported with it has been favorable (135, 368, 373). 

An Oldershaw column and a pilot test column were successfully used for detecting foaming (407, 408). This technique is most suitable for atmospheric and vacuum columns, but may have difficulty reproducing all conditions such as pressure and solids content. It is best to use a sample of the actual column mixture in this test. 

An armored level glass technique (Fig. 14.12c), which is capable of duplicating plant conditions of temperature, pressure, and composition. The level glass can be mounted either in the laboratory (50) or in the field (203). This technique is more reliable than any of the above, as it reproduces actual plant conditions. Both case histories above reported success with this technique where other techniques failed. 

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Fire Tests for Foamed Plastics Used for Decorative Purposes, 1990. 

The acceptance test for foam-water sprinkler and water spray systems is similar to systems without foam. Tests include ... 

UL 1975 Standard for Fire Tests for Foamed Plastics Used for Decorative Purposes UL 2024 Standard for Optical-Fiber and Communications Cable Raceway UL 2043 Standard for Safety Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air-Handling Spaces... 

UF 1975, Standard for Fire Tests for Foamed Plastics Used for Decorative Purposes, Underwriters Faboratories, Northbrook, IF. 

A flammable aerosol is classified in one of the two categories for this Class on the basis of its components, of its chemical heat of combustion and, if applicable, of the results of the foam test (for foam aerosols) and of the ignition distance test and enclosed space test (for spray aerosols). See decision logic in 2.3.4.1. 

Foam Number A relative drainage rate test for foams in which a foam is formed in a vessel and thereafter the remaining foam volume determined as a function of time. The foam number is the volume of bulk liquid that has separated after a specified time interval, expressed as a percentage of the original volume of liquid foamed. 

Gas processing Hot pot absorber (padied) Foaming occurred because a corrosion inhibitor iqjected into the gas well ended up in the column. Laboratory tests did not identify the problem. Tests under actual oparating conditions did. Antifoam iiyection solved it Tests for foaming are best carried out under actual plant operating conditions. 

The test for foaming is to obtain a sample of the fluid and gas from the process step, add the inhibitor in question, adjust the temperature to that corresponding to the process step and shake vigorously. If this test produces a stable foam, a potential problem exists. Pressure suppresses foam some foams that exist at atmospheric pressure will not exist at system pressure. 

The test for foaming should be performed. Most corrosion inhibitors cease to function at a pH below 3. Normal fihn-forming organic inhibitors of the water-soluble type have an upper temperature limit of 140 °C (300 °F), while oil-soluble inhibitors have a limit of 196°C(385°F), when cooled the inhibitor is active again, so it is not destroyed if the temperature is not too high. 

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