Valorization of tea wastes by pyrolysis

Abstract

Pyrolysis behaviors and yields of liquid products of tea waste supplied from Surmene-Trabzon Caykur Factory in The Eastern Black Sea Region of Turkey were determined catalytically. The conversion of tea waste to liquid products has been examined in the presence of alkali and metal additives at different temperatures. The pyrolysis experiments were performed in a device designed for this purpose. The main element of this device was a stainless-steel cylindrical reactor vertically-heated by an electric tubular furnace with the temperature being controlled by a simple thermocouple (Ni-Cr constantan) inside the bed. The yields of liquid product were increased with using of catalysts at the final pyrolysis temperature of 723K with respect to non-catalytic pyrolysis. At 973K, the yields of liquid were only increased with using of Na 2CO 3 catalyst, but K 2CO 3 and ZnCI 2 are not effective much on pyrolysis. The catalytic effect of K 2CO 3 was greater than that of Na 2CO 3 at 723 K and vice a versa at 973K. The liquid fraction of the pyrolysis products consists of two phases: an aqueous phase containing a wide variety of organo-oxygen compounds of low molecular weight and a non-aqueous oily bottom phase containing insoluble organics of high molecular weight. This phase is called as bio-oil or tar and is the product of greatest interest. © Sila Science.