Dielectric Barrier Discharge Plasma Synergistic Catalytic Pyrolysis of Waste Polyethylene into Aromatics-Enriched Oil

Abstract

The dielectric barrier discharge (DBD) plasma synergistic catalytic pyrolysis scheme was developed for upgrading polyethylene (PE) pyrolysis volatiles to obtain aromatics-enriched oil. The effects of the PE/HZSM-5 ratio, discharge power, and discharge time interval on the product yield, oil composition, and carbon deposition were studied by the experiment. When the PE/HZSM-5 ratio shifted from 5:1 to 1:5, the oil yield decreased first and then ramped to 51.32%. The selectivity for aromatics in oil increased from 69.93 to 98.43%. In the discharge power range of 0–15 W, increasing the power increased the aromatic content with the maximum of 98.14%, consequently decreasing the alkane and alkene contents of the product oils. The further addition of the power resulted in a small decrease in the selectivity for the aromatics. The coke showed a decrease in yield with increasing discharge power when the power did not exceed 20 W. The maximum selectivities for aromatics (97.69%) and the minimum coke yield (2.82%) were obtained at the discharge time intervals of 2.5 and 5 ms, respectively. In general, both of the free radicals excited by the plasma and the specific surface area, acidity, and strength of HZSM-5 changed by the plasma favored the aromatization reaction.

Rich-O-Vacancy WO3/ZrO2–Hβ with High Lewis/Brønsted Ratio: An Efficient Catalyst for the Highly Selective Synthesis of Dipropylene Glycol

“…According to the report of Gonzaĺez, 24 and Brønsted acid sites (1546 cm −1 and 1620−1640 cm −1 ); the 1490 cm −1 band detected by all Py-IR spectra is assigned to Lewis and Brønsted acid sites. 61,62 The maximum peak of 20ZrO 2 −Hβ and 30WO 3 /20ZrO 2 −Hβ shifted from 1442 to 1446 cm −1 due to the desorption of pyridine from the weaker acid sites. 61 The relative and density characteristics of Lewis to Brønsted acid can be estimated from the intensity ratio of the bands at 1454 and 1546 cm −1 after desorption at 200 °C.…”

Recent Advances in Plasma Catalysis

“…Song et al placed DBD coupled with HZSM-5 downstream of polyethylene pyrolysis volatiles to generate aromatics-enriched oil and showed product yields are sensitive to plasma conditions. 24 ■ PLASMA-ASSISTED SYNTHESIS AND…”

“…In both cases, reactant conversions with plasma–catalyst combinations are higher than those with plasma alone or catalyst alone under tested conditions. Song et al placed DBD coupled with HZSM-5 downstream of polyethylene pyrolysis volatiles to generate aromatics-enriched oil and showed product yields are sensitive to plasma conditions …”

Plasma-Catalytic Reforming of Naphthalene and Toluene as Biomass Tar over Honeycomb Catalysts in a Gliding Arc Reactor

“…However, the industrial applications of this technology are limited due to low selectivity toward the specific products and the generation of byproducts . To deal with this issue, the hybrid plasma-catalysis technology has shown great potential as it can combine the advantages of the fast reaction rate of NTPs and the high selectivity of the catalyst with the high activity. − The synergistic effect might be generated in the hybrid plasma-enhanced catalytic system, where the catalysts can be activated at low temperatures with high reactivity and strong carbon resistance. − Currently, dielectric barrier discharge (DBD) has attracted intense attention in the plasma-catalytic reforming of biomass tars as it has strong flexibility to be combined with catalysts to promote the conversion of tar model compounds and the yield of specific products while suppressing the formation of undesired byproducts. − Nevertheless, the energy efficiency of the tar reforming process based on DBD plasma coupled with catalysis is still unsatisfactory due to the limited treatment capability and power levels.…”