Co-pyrolysis of coffee-grounds and waste polystyrene foam: Synergistic effect and product characteristics analysis

摘要

Coffee-grounds (CFs) are simultaneously pyrolyzed with waste polystyrene foam (PS) in a bubbling fluidized bed reactor according to the following conditions: a temperature of 500 ?C selected from the thermogravimetric analyses of CFs and PS, the nitrogen flow rate of about 20?25 L/min., and the feeding rate of 200 g/h. Multiple CFs/PS mixing ratios were treated as follows: 75:25, 50:50, 25:75. The properties, the chemical compositions of the co-pyrolysis oils and the yields of the products were compared with those of the pyrolysis-oils of the individual feedstocks to demonstrate the synergy between the CFs and the PS. The synergy with the co-pyrolysis produced a higher liquid yield than the calculated amount. The higher heating value of co-pyrolysis oils increased to 39.66 MJ/kg, which was equivalent to that of conventional fuels. Blending at least 25% of PS to CFs could greatly reduce the viscosity of CFs pyrolysis oil (from 724.65cP to 29.3cP at 24 ?C). Chemical distributions have shown that the synergy effect between CFs and PS has drastically enhanced the production of hydrocarbons, especially in aromatic compounds.