Effect of addition copper metal balls on pyrolysis temperature and properties of biochar from spent coffee ground

Abstract

In this study, slow pyrolysis of spent coffee ground (SCG) in cylinder shape fixed bed reactor was investigated with the aim to develop the way increasing the heating rate of SCG in the center of reactor. The small metal balls 8 mm. diameter were used as the thermal distributor within the final temperature 500°C, 50 ml/min of N2 gas flow, and 2 hrs. holding time. The results reveal that the heating rate of spent coffee ground with small metal balls (SCG+MB) was increased in the range of temperature 351.5 - 461.5°C faster than the pyrolysis of SCG and could reduce 5.98% electric consumption for heating the reactor. The yield of bio-char from experiments are not different significantly as well as the content of Volatile matter, ash, fixed carbon and higher heating value of the products.  The specific surface area, pore volume and pore size tend to increase due to the effect of addition of metal balls could rise duration time of the thermochemical decomposition, iodine adsorption of the SCB+MB bio-char is 590 mg/g which is 118.51% higher than SCG bio-char at 270 mg/g. These results claim that the pyrolysis which having metal balls can improve the raising of heating rate of the pyrolysis and could upgrade the properties of product biochar to be prepared for primary materials for further use.