Publication: Catalytic co-pyrolysis of high-density polyethylene/polypropylene mixture and oil palm fibre to liquid fuel
Date
2022-09-01
Authors
Abel Williams Gin
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Abstract
Green House Gas (GHG) emission and environmental pollution remain the two main issues of concern in the globe today because of the continuous and unrestricted dumping of both plastic and agricultural biomass residues across the globe. Hence, a conversion of these solid wastes into highly valuable liquid fuel could be a potential solution to alleviate this environmental issue. In this work, oil palm fibre (OPF), a major agricultural biomass in Malaysia, was mixed with an equal mass of high-density-polyethylene (HDPE) and polypropylene (PP) and converted to liquid fuel via non-catalytic and catalytic co-pyrolysis in a fixed-bed-reactor. The synthesized catalysts, SBA-15 exhibited a highly ordered mesoporous structure while ladle furnace derived - hydroxyapatite (HAP-LF) demonstrated metal-rich microporous structure, respectively. The influence of process parameters
(temperature, feedstock ratio, catalyst/feedstock ratio) indicated that the maximum composition of the desirable compounds (alcohol and hydrocarbons) using HAP-LF was 71.65 % (Temperature = 450 oC, OPF-plastic mixture ratio = 1:3). The yield of these compounds was higher than maximum value of 60.54 % obtained using SBA 15 (600 oC, OPF-plastic mixture ratio = 1:1). The HAP-LF catalyst/feedstock ratio of 1:8 produced the maximum composition of the desired compounds in oil while SBA 15 catalyst/feedstock ratio of 1:6 produced maximum composition of the desired compounds. These results indicated that HAP-LF is a more suitable catalyst for the catalytic co-pyrolysis of the feedstock mixture. The heating value of the produced oil was found to be 44.5 kJ/mol. Recyclability studies of the HAP-LF catalyst indicated that it could be used up four consecutive recycle times without serious deactivation. The kinetic studies using thermogravimetric analyzer showed a reduction in activation energy from 13.98 - 92.11kJ/mol to 21.58 - 59.33 kJ/mol across the three degradation stages of the feedstock mixture.