SPECIAL REPORT
On Pittsburgh Granular Activated Carbon
HOW CARBON WORKS FOR PRODUCT PURITY, SAFETY AND ECONOMY. Pittsburgh Granular Activated Carbons have found wide acceptance and success in the chemical, pharmaceutical and food processing industries, among others, for the purification and decolorization of numerous solutions and products. Designed for efficient use in fixed or moving bed columns, these carbons provide maximum process efficiency at lower costs. For example, a properly designed system offers: a cleaner, continuous operation; more efficient utilization of the activated carbon (including regeneration for repeated use); less equipment and floor space; lower carbon dosage and costs; improved product quality and a purer and safer process. REFINING CORN SYRUP. In the production of corn syrup, corn starch slurry is hydrolyzed at elevated temperatures to form polysaccharides and other forms of sugar. This hydrolysis is carried out with the aid of either hydrochloric acid or enzymes and, in some cases, both. This reaction is stopped while only partially complete in order to isolate the desired PROCESS FLOW DIAGRAM OF A MOVING-BED SYSTEM DESIGNED BY PITTSBURGH ACTIVATED CARBON COMPANY
Carbon Feed Tank
Treated Juice Return
Regenerated Carbon
hydrolyzate concentrations In the syrup. The different types of corn syrup have various levels of concentration and these are controlled by the reaction temperature and amount of acid or type of enzyme, depending on the 'process. The next processing objective is to remove any undissolved fats, proteins, and waxes by the use of centrifugals and/or filtration. However, the corn syrup is far from product specification at this point. The syrup is evaporated to 33% to 45% dry substance and then passed through beds of Pittsburgh Granular Activated Carbon. The carbon removes the dissolved color bodies and the effluent solution is sometimes as clear and colorless as water. The purified syrup is then directed to a triple effect evaporator and finishing pan to produce the 80% dry substance product. TREATING NATURAL GLYCERINE The hydrolysis or saponification of fats and oils in the manufacture of free fatty acids and soaps yields glycerine as a by-product. There are at least five different grades of natural glycerine being produced commercially, however, activated carbon is primarily used in the manufacture of the USP (U. S. Pharmacopoeia) and CP( Chemically Pure) grades. The crude grade is refined by steam distillation under vacuum and the 88% glycerine is concentrated for further purification. This viscous yellow liquid at 150°F. to 200°F. is then pumped through Pittsburgh Granular Activated Carbon for the removal of fatty acids and esters. STRIPPING BUTADIENE Butadiene is produced by the dehydrogenation of butane or butènes using chrome alumina type catalysts at 600°C. Butène Spent Carbon
Carbon Columns
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and butadiene cannot be effectively separated by conventional distillation because of close boiling points, and it is customary to use a cuprous ammonium acetate (CAA) solvent to selectively complex butadiene which is then stripped with heat. To prevent foaming and loss of selectivity in the solvent due to contaminating materials, a five to ten percent side stream (of total solvent flow) is passed through beds of Pittsburgh Granular Activated Carbon. Because it handles easily and has extremely high capacity for impurities, the carbon not only reduces foaming and maintains selectivity in the CAA, but increases production rates as well.
FILTERING AMINE SOLUTIONS. Ethanolamines are widely used for the purification of gas streams due to their ability to absorb carbon dioxide and/or hydrogen sulfide. These amine streams, which may contain mono-, di- or tri-ethanolamine, are recirculated for continuous operation. It is only a matter of time until the level of impurities reaches the point that foaming, corrosion, and loss of efficiency begin to plague the system. For this reason, Pittsburgh Granular Activated Carbon has been used for many years to remove the contaminants from the amine stream. These carbon filters are used on the lean cold side of the recirculating stream for highest efficiency. Usually only a 1 % to 2% slipstream of the total flow must be carbon treated in order to maintain an acceptable amine solution. Use of Granular Activated Carbon will significantly reduce the need for expensive anti-foam agents. WHERE ELSE CAN CARBON WORK. There are many other applications where carbon can be used effectively for the purification of a product. Granular carbon beds also provide that valuable extra margin of safety in the event your feed material does not meet the usual specifications. In many instances, your by-product or principal product may be sold in new markets due to the quality level possible when utilizing Pittsburgh Granular Activated Carbon. This new-found economy of operation could be the answer you are seeking. Write or call us: Pittsburgh Activated Carbon Division, Calgon Center, Pittsburgh, Pa. 15230 PITTSBURGH ACTIVATED CARBON DIVISION OF CALGON CORPORATION SUBSIDIARY OF MERCK & CO., INC.
