Fuel Range Properties of Oil and Wax Obtained from Catalytic Pyrolysis of Linear Low-Density Polyethylene in a Fluidized Bed Reactor (FBR)

Abstract

Virgin linear low-density polyethylene was subjected to pyrolysis in a fluidized bed reactor pilot plant segmented into three heating zones with both sand and Magnofil BT 80 catalyst as bed materials. The pyrolysis oil and wax products were extracted at an average bed temperature of 600 and 700 °C. The oil yield decreased between 600 (8.7 wt %) and 700 °C (8.1 wt %) in an inverse relationship with the reaction time (358 and 384 min, respectively). This was attributed to an increase in the vibration of the polyolefin polymer matrix as a result of the absorbed thermal energy with an increase in temperature. The experiments performed at 700 °C showed no wax formation but high yields of gaseous products and oils, which are more lucrative in managing accumulated plastic waste, of which polyethylene constitutes large proportions, via thermochemical conversion technologies. The estimated calorific value at 600 °C was 45.5 MJ kg–1, which is in the acceptable range for both diesel and gasoline fuel market specifications. The sulfur content in the pyrolysis oil was estimated to be 0.013% and was not affected by changes in the temperature of the fluidized reactor. However, desulfurization will be required in the future to obtain oil within acceptable ranges of clean fuels. In addition, to support this work’s results in obtaining fuels from such feedstock materials, the fuel range hydrocarbons were also analyzed. The diesel fuel hydrocarbon range (C10–C19) was between 37 and 60% in the pyrolysis oils examined. The results determined experimentally from the pilot-plant work herein are quite promising for sustainable fuel integration plans in the near future with existing petroleum refining complexes.

Process Simulation Modeling of the Linear Low-Density Polyethylene Catalytic Pyrolysis in a Fluidized Bed Reactor

“…The fuel range HCs with respect to the reactor bed temperature are displayed in Table . The results show that the diesel range HCs had the greatest yield (C 10 –C 19 ); this is in accordance with the experimental data discussed prior Table shows the comparative yields obtained using the process simulation modeling and experimental work .…”

“…Therefore, the process simulation model has demonstrated good validity with the experimental work. The mass balance and individual product yields were calculated using the following equations: pyrolysis total 0.25em gas 0.25em yield % = 100 − [ total oil % + total wax % + total char % ] pyrolysis 0.25em normalp 0.25em yield % = m normalp / m normalf × 100 where m p and m f are the weighed pyrolysis product fraction and the total feedstock mass, respectively. The results showed that as the temperature increased from 500 to 700 °C, the total gas yield increased.…”

“…The theoretical model will be based upon and validated against previous experimental work studying the pyrolysis of LLDPE in the FBR. 23 The comprehensive process simulation will determine the oil and wax products at 600 and 700 °C and investigate the properties of this range of fuel produces using a catalytic FBR system, which can provide a promising pathway for PSW management via pyrolysis. The current work is highly novel as the computational modeling on the pyrolysis of LLDPE in a FBR system is not widely reported in literature.…”

“…Hence, in addition to thermal decomposition, the catalyst would promote the catalytic cracking of HCs in PW. The theoretical model will be based upon and validated against previous experimental work studying the pyrolysis of LLDPE in the FBR . The comprehensive process simulation will determine the oil and wax products at 600 and 700 °C and investigate the properties of this range of fuel produces using a catalytic FBR system, which can provide a promising pathway for PSW management via pyrolysis.…”

“…The current work is highly novel as the computational modeling on the pyrolysis of LLDPE in a FBR system is not widely reported in literature. For the first time, the study is conducted using an innovative FBR experimental setup developed by the research group of ref for this specific feedstock rich in PW. The computational model has proven a good validation with the experimental results and therefore can be adapted to investigate the pyrolysis of different feedstocks.…”