Bench-scale tests, activated carbon

The best approach to evaluate the effectiveness of activated carbon adsorption is to run bench-scale tests on your waste stream. 

Another potential limiting factor relating both to the feed composition and the combustion process is the incomplete destruction of PCDD/Fs present in the incoming waste. For example, if the MSW contained a trace quantity of PCDD/Fs at a concentration of, say, 50 fig 1-TEQ tonne 1 (wet) and if 99% was destroyed in the combustor, then the uncombusted PCDD/Fs would contribute a concentration of 0.1 ng I-TEQ Nm-3 in the exit gas, assuming that physical and chemical processes in the post-combustion zone (for example, adsorption on activated carbon) do not alter the composition of the combustion gases during their passage to the stack. This process is not well understood, and requires further elucidation in bench-scale tests. 

In the commercial plants, the conversion and the selectivity declines due to coking of the catalyst. The amounts of deposited carbon were estimated after 100 h operation of both the catalysts and found to be 0.05 and 2.5% for the PDIL and imported catalysts respectively. The regenerative property of the catalyst is another choice of the users. In this respect, the PDIL catalyst (CD-ED-101) could be regenerated at 400°C by a stream of air, atleast three times without any significant loss of the activity and selectivity. The indigenously developed catalyst was tested in the bench scale testing unit for 200 h and there was no loss of activity or decline in selectivity. On the basis of these informations and test results the PDIL catalyst (CD-ED-101) may be considered superior to the imported catalyst. 

Fig. 3.3 Activated carbon powder (photographed under an optical microscope) used in construction of carbon-coated electrodes for bench-scale testing of Zn/Br RFBs (Kindly provided by Martin Schneider of the Energy Storage Group at the University of Sydney.)...

The mercury removal performance of the activated carbon samples produced in this study were measured both in a bench-scale test apparatus and in a sorbent injection pilot-plant. 

Pecan-shell-based granular activated carbon (GAC) has only been tested at bench-scale, and experiments are ongoing. The principal research institutions involved in this research are New Mexico State University and the Southern Regional Research Center, in collaboration with Lonisiana State University. 

A major concern regarding the use of this technology under such rapidly fluctuating pressures is the stability of the adsorbent. Long-term testing of several types of synthetic zeolites and activated carbon in bench-scale, large-pilot-scale, and commercial units has demonstrated that adsorbent lifetimes of well over one year are to be expected in most applications. 

The Pd catalysts, both on alumina and carbon, were tested in a bench scale reactor studying the reduction of 1 g of acetophenone in 10 cm of absolute ethyl alcohol at atmospheric pressure. The runs were performed at 24 C for the Pd/C samples and at 34 and 44 C for the Pd/Al203 samples. The activity values were measured by the consumed hydrogen in cm /min. 

A batch, 48-cm ID pilot-scale FBR was used to produce more than 60 kg of activated carbon from C2 coal. Pilot tests were conducted at Svedala Inc., a chemical process equipment firm located in Oak Creek, Wisconsin. Five pilot production tests were made. The processing conditions employed in the pilot production runs were comparable to those identified during the bench-scale studies of coal C2 except that about 50 kg of <0.25 mm coal was typically used. 

Bench-scale mercury testing was conducted at Radian International s Austin, Texas laboratory. The screening tests evaluated mercury breakthrough characteristics of ICDAC samples and Darco FGD carbon, a hgnite-based activated carbon manufactured by American Norit. 

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