Cooling water acid cleaning

S. cerevisiae is produced by fed-batch processes in which molasses supplemented with sources of nitrogen and phosphoms, such as ammonia, ammonium sulfate, ammonium phosphate, and phosphoric acid, are fed incrementally to meet nutritional requirements of the yeast during growth. Large (150 to 300 m ) total volume aerated fermentors provided with internal coils for cooling water are employed in these processes (5). Substrates and nutrients ate sterilized in a heat exchanger and then fed to a cleaned—sanitized fermentor to minimize contamination problems. 

Plate and frame coolers using HasteUoy C-276 plates have been used successfuUy. Anodically protected plate coolers are available as weU as plate coolers with plates welded together to minimize gasketing. Another promising development is the introduction of plate coolers made of HasteUoy D205 (105). This aUoy has considerably better corrosion resistance to concentrated sulfuric acid at higher temperatures than does C-276. Because of the close clearance between plates, cooling water for plate coolers must be relatively clean. 

NOTE The view that deposition is an indicator of more widespread problems is also common to cooling water systems. As a result of the complex nature of deposits, their removal by acid or mechanical cleaning of boiler or cooling systems is not always as simple a process as may be portrayed. 

Will These Two Materials React Acetic Acid Acetic Anhydride Cooling Water Sulfuric Acid 50% Caustic Lube Oil Cleaning Solution... 

If you use an acid or base to clean your electrodes, treat both the acid or base and the electrode with caution. Wash any spills on your skin with plenty of cool water. Inform your teacher. 

After the desired contact time, stop adding acid. Provide as heavy a bleed of water as the production process permits to remove dead slime from the cooling system. Reuse surface skimmers. Allow fresh makeup water to raise the recirculating water pH to 7.6-7.8 or so. Only move to the next stage of cleaning when the water looks clean. This may take many hours. 

Organic compound, such as ethylenediamine-tetraacetic acid (EDTA), having the ability to take metal ions in water and produce soluble complexes, occasionally used in cooling water deposit control and cleaning formulations. 

Supplies Put 5 cc. of water in a test tube and slowly pour upon it 15 cc. of concentrated sulphuric acid. Cool the acid by holding the test tube in a stream of cold water. Put 5 to 7 cc. of alcohol in the test tube A, add a little clean sand, or a few glass beads, and then slowly pour in the cold acid. Two or three small bottles will be needed. A dish should stand under A to catch the contents, in case of accident. 

When the residue is carbonized and is not greatly affected by the treatment described above, then proceed thus Place 1-2 g of solid sodium dichromate in the flask add 1-2 ml of water place in the hood with the mouth of the vessel away from you and towards the wall of the hood. Add 5-10 ml of concentrated sulfuric acid (technical grade). Clamp the vessel on a stand and heat with a free flame. If a reaction starts, remove the flame until it subsides, then heat until most of the tarry carbon has disintegtated. Allow it to cool. Pour acid mixture into a beaker and then rinse with water. The acid-mixture residue is carefully poured into the sink, unless it contains tarry matter which may cause clogging. The student is reminded that potassium permanganate is never used in place of potassium dichromate for cleaning solution. 

Chromic acid cleaning mixture. Dissolve 10 g of sodimn dichromate in 10 ml of water in a 400 ml beaker. Add slowly with careful stirring 200 ml of concentrated sulfuric acid. The temperature will rise to nearly 80°. Allow the mixture to cool to about 40° and place... 

Cleaning in freshly prepared and cooled chromic acid, followed by thorough rinsing with deionized water [21, 74]. 

---