The concept as well as the desirability of utilization of activated carbon filtration for purification of amine and glycol solutions has been recognized for some time. coconut shell activated carbon manufacturers Most carbon filtration installations have been made as a result of “rule of thumb” design criteria, and considerably more art than technology was required to effectively predict the performance of an activated carbon filter.
The utilization of diethanolamine for treating purposes in newer plants, as well as conversion of older plants, has resulted in a new sense of urgency to develop a solution purification process for these plants. Since reclaiming has not been successful on diethanolamine solution, filtration is the only readily available method of cleaning DEA solutions. Also dirty glycol solutions have been tolerated for a number of years. Glycol solutions can be reclaimed under vacuum, but this is very seldom done on small field units.
Concurrent with the above, certain new processes and new techniques in activated carbon filtration have been developed in the last few years. It now appears that when properly installed and operated, activated carbon filtration may be used exclusively for purification of amine solutions. Activated carbon filtration of glycol systems is not as essential, but can be highly desirable and should be reviewed for possible application in those glycol units where the glycol has become contaminated.
In the original concept of using activated carbon filtration for amine and glycol systems, it appeared that conventional mechanical filters (such as “sock” type filter) would be utilized to remove the solids from the stream but not necessarily those contaminants which were in solution or in an emulsion form. These impurities would be removed by a fixed activated carbon bed installed downstream from the mechanical filters.
In systems of this type, where the activated carbon was used merely as an adsorptive process to remove contaminants, the carbon bed would be of a relatively small size. wholesale bulk activated carbon Cross-sectional areas would normally be sufficient for flow rates of between 1 and 5 gpm per square foot, with bed depth approximately 3 to 10 feet. The carbon utilized would normally be a high bulk density, gas adsorption grade of carbon, either coke base or coconut shell base. Wood base carbons were seldom used. Carbon particle size would be relatively large (4 x 8 mesh, etc.), with at least one system utilizing crushed activated charcoal briquettes.
In operation of this system, the carbon would be used until contaminated and then dumped. Most literature sources report that superheated steam is necessary to regenerate this carbon. These units would normally be installed as side stream filters, processing between 1 and 2% of the total circulation.
In general, these systems met with only partial success. Removing solid particulate matter completely from the system required changing the filter elements too often. The activated carbon bed would be too small and too limited in size to remove solid materials from the solution. Their ability to remove dissolved and entrained liquid contaminants depended on bed capacity and the length of time between changes.