Abstract
The suitability of raffinate (non-aromatic hydrocarbon oil) as solvent for asphalt was investigated. The experimental results were as follows;
When char, precursor from asphalt to activated carbon, was produced in the raffinate as solvent, boiling at 90-150°C, a portion of raffinate reacted with acid and the produced granulated char was changed to lumps with over 4 mesh size. This phenomenon was dissolved by using the higher fraction of raffinate. The raffinate boiling at 120-150°C was the most suitable for producing granulated char.
The hardness of char obtained by using 5/1 (wt./wt.) of the raffinate boiling at 120-150°C and 1.5/1 (wt./wt.) of 25%-oleum to asphalt was larger than that of char obtained by using 10/1 (wt./wt.) of 1, 1, 2-trichloroethane and 1.5/1 (wt./wt.) of 60%-oleum to asphalt.
The average recovery of the raffinate was about 95% and it was 2-3% lower than that of halogenated hydrocarbons or n-paraffines Accordingly, it was clear that an interraction between solvent and acid as pretreatment reagent took place in case of the raffinate.
It was easy to produce granulated char from asphalt by adding some powdered char as raw material with raffinate, and the optimum weight ratio of powdered char to asphalt was 10% by weight.
When char was activated with steam at 850°C for 30 min., the yield of the activated carbon was 42-55% based on asphalt. This yield was relativery higher than the activated carbon from 1, 1, 2-trichloroethane as a solvent, but the specific surface area of the former was relatively smaller than the latter.
