Characteristics Analysis And Quality-improving Experiment Of Char By Pyrolysis Of Scrape Tires In A Pilot-scale Rotary Kiln

The pyrolytic products of scrape tires include pyrolytic oil, solid residue that is also referred to as char and gas. This paper focused on the solid residue from pyrolysis of scrape tires in a pilot-scale rotary kiln and conducted all-round analysis and experimental investigation, namely, analysis of char characterizations as well as important factors during pyrolysis, activation study of char, aqueous adsorption ability investigation of char and activated char.(1) Analysis of CharThis paper performed general analysis of Char, including char yields, components and particle size. As one of the most vital reaction parameters, the influent of temperature upon char property has been considered. Relations between char yields and temperature was studied. On partical size of char, the average diameter, particle size distribution with mass and influence of temperature were investigated. Approximate and ultimate analysis were conducted to ditermine the main ingredients of char, SEM (Scanning electron microscope) analysis as well. Based on the analysis above, this paper proposed optimized reaction conditions take char into chief consideration.Ash content would affect char's quality. As an impotant quality-improving approach, this paper acid-washed char with hydrochloric acid and sulfur acid to get rid of or reduce ash content. The results of acid wash with different acid concentration, reaction time and acid temperature were discussed.Pore structure is most important for such a granular carbonaceous material as char. Having Combined NI adsorption method and mercury-displacing method, this paper investigated the characteristics of pore structure. Pore size distribution, specific surface area, specific pore volumn and average pore diameter were determined. The trend of specific surface area varied with temperature was discussed. And comparisons were made between pore distribution of two chars with different particle size.The application of char is one of the key part of scrape tires pyrolysis and also main concern of this paper. On the basis of char analysis, this paper discussed commercial applications of char in details. Compared with certain commersial carbonblack, char application in rubber industry was tested.(2) Activation of charChar activations were studied in this paper. Three activating agents were used, that is CO2, Stream and O2 (air). The chief factors concerned during activation were temperature, soaking time, flow rate and kinds of activating agents.Relations between surface area of char and temperature and time were discussed, as well as those between Burnoff and temperature and time. Moreover, surface area varied with Burnoff were studied.Concerning the evaluation of activation, differing from ordinary avaluation method, this paper combined the increasement of surface area and Burnoff (defined as mass loss of carbon element), put forward evaluating factor of activation Φ to evalutate the result of activation. Activations with different agents were compared. The pore distribution of char was compared with that of a commercial activated carbon.(3) Aqueous adsorptionExperiments on aqueous adsorption ability of char and activated char were conducted in this paper. Three solutions with different molecule size were used, namely, Phenol, Iodine and Methylene Blue. The influence of surface area and Burnoff on chars' adsorption was investigated.Overall-effect factor ψi was introduced to evaluate activation in consideration of surface area, Burn-off and aqueous adsorption.Again, an overall evaluating factor of activating was introduced to consider surface area, Burnoff and adsorption ability. Adsorption ability of activated chars' with different agents was discussed and compared with those of two commercial activated carbons for water cleaning.