Plastic pyrolysis over HZSM-5 zeolite and fluid catalytic cracking catalyst under ultra-fast heating

Wong, Syieluing; Armenise, Sabino; Nyakuma, Bemgba Bevan; Bogush, Anna; Towers, Sam; Lee, Chia Hau; Wong, Keng Yinn; Lee, Ting Hun; Rebrov, Evgeny V.; Muñoz, Marta

doi:10.1016/j.jaap.2022.105793

Cited by 44 publications

(8 citation statements)

References 63 publications

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“…Liquid yields for the catalytic pyrolysis of PP over H-ZSM-5 zeolite catalysts are generally lower than 60%. Here, yields are a function of reaction conditions and are lower than those for thermal pyrolysis. − Solid yields in this work are on the low end for the zeolite-catalyzed pyrolysis of polyolefins. Typically, solid yields are around 1–20% on intake, depending on the process conditions, catalyst loading, and reactor type.…”

Section: Results and Discussionmentioning

confidence: 95%

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics

He,

Osorio Velasco,

Strien

et al. 2024

Energy Fuels

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Pyrolysis of lignocellulosic biomass and waste plastics has been intensely studied in the last few decades to obtain renewable fuels and chemicals. Various pyrolysis devices have been developed for use in a laboratory setting, operated either in batch or continuously at scales ranging from milligrams per hour to tenths of g per hour. We report here the design and operation of a novel staged free-fall (catalytic) pyrolysis unit and demonstrate that the concept works very well for the (catalytic) pyrolysis of pinewood sawdust, paper sludge, and polypropylene as representative feeds. The unit consists of a vertical tube with a pretreatment section, a pyrolysis section, a solid residue collection section, a gas−liquid separation/collection section, and a catalytic reaction section to optionally perform ex situ catalytic upgrading of the pyrolysis vapor. The sample is placed in a tube, which is transported by gravity through various sections of the unit. It allows for rapid testing with semicontinuous feeding (e.g., 50 g h −1 ) and the opportunity to perform reactions under an (inert) gas (e.g., N 2 ) at atmospheric as well as elevated pressure (e.g., 50 bar). Liquid yields for noncatalytic sawdust pyrolysis at optimized conditions (475 °C and atmospheric pressure) were 63 wt % on biomass intake. A lower yield of 51 wt % (on a biomass basis) was obtained for the noncatalytic pyrolysis of paper sludge, likely due to the presence of minerals (e.g., CaCO 3 ) in the feed. The possibility of using the unit for ex situ catalytic pyrolysis (pyrolysis at 475 °C and catalytic upgrading at 550 °C) was also successfully demonstrated using paper sludge as the feed and H-ZSM-5 as the catalyst (21 wt % catalyst on biomass). This resulted in a biphasic liquid product with 25.6 wt % of an aqueous phase and 11 wt % of an oil phase. The yield of benzene, toluene, and xylenes was 1.9 wt % (on a biomass basis). Finally, the concept was also proven for a representative polyolefin (polypropylene), both noncatalytic as well as in situ catalytic pyrolysis using H-ZSM-5 as the catalyst at 500 °C. The liquid yield of thermal, noncatalytic plastic pyrolysis was as high as 77 wt % on plastic intake, while in situ catalytic pyrolysis gave a combined 7.8 wt % yield of benzene, toluene, and xylenes on plastic intake.

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Section: Results and Discussionmentioning

confidence: 95%

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics

He,

Osorio Velasco,

Strien

et al. 2024

Energy Fuels

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“…In Figure , the main components of H 1 (primary reactor at 550 °C and second reactor at 350 °C with HZSM-5 as the catalyst) are propane, propene, and butane, which correlate well with other studies. , In addition, a higher C 3 hydrocarbon content, at the expense of methane, ethane, and ethene, can be observed . It could also be observed that the total gas yield of H 2 –H 4 is higher compared to H 1 , showing more extensive vapor cracking.…”

Section: Resultsmentioning

confidence: 98%

“…50,51 In addition, a higher C 3 hydrocarbon content, at the expense of methane, ethane, and ethene, can be observed. 52 It could also be observed that the total gas yield of H 2 −H 4 is higher compared to H 1 , showing more extensive vapor cracking. In addition, the olefin content gradually grows with a higher second reactor temperature in experiments H 2 −H 4 , which could be due to the enhanced cracking of alkanes.…”

Section: Product Distribution Tablementioning

confidence: 93%

Two-Stage Fixed-Bed Low-Density Polyethylene Pyrolysis: Influence of Using Different Catalytic Materials in the Second Stage

Hu,

Sárossy,

Jensen

et al. 2023

Energy Fuels

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Pure low density polyethylene pyrolysis was investigated using a lab-scale two-stage fixed-bed pyrolyzer with different catalytic materials in the second reactor for upgrading the vapors. The yields of gas and char were determined, and the condensed product was thoroughly examined by gas chromatography–mass spectrometry and thermogravimetric analysis. The use of different catalytic materials such as HZSM-5, cement raw meal, calcined cement raw meal, and silicon carbide was investigated. A wax-rich condensed product (intermediate molecular weight hydrocarbons) was observed in the following types of experiments: no catalyst, silicon carbide, and cement raw meal in the second reactor. The wax was mainly composed of alkanes and alkenes. The use of an HZSM-5 catalyst and applying temperatures from 350 to 500 °C in the second reactor highly decreased the chain length of hydrocarbons in the condensed product and converted the wax into a liquid. When the second reactor temperature was higher than 400 °C, the main product components were aromatics and naphthalene. Using calcined raw meal in the second reactor at a temperature of 600 °C also led to the conversion of the wax to a liquid product with a large fraction of cyclic aliphatics.

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“…Catalysts can play a vital role in pyrolytic reactions as they can lower the activation energy, which results in lower pyrolysis temperatures and energy requirements and can also influence the distribution of products by favoring the selectivity towards target products [69]. The use of numerous catalysts can be found in the literature as zeolites and zeolites-based compounds (i.e., ZSM-5, H-ZSM-5, spent fluid catalytic cracking catalyst [70,71], Zn-ZSM-5 [72], and natural zeolites [73]), metals (i.e., magnesium oxide [74], copper carbonate [75], nickel-based [76], zinc [77], and sulphated zirconia [78]), or minerals (i.e., kaolin [79], iron-pillared clay [80], and dolomite [81]).…”

Section: Operational Conditionsmentioning

confidence: 99%

Municipal Plastic Waste Recycling through Pyrogasification

Moliner,

Pasquale,

Arato

2024

Energies

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Conventional mechanical recycling technologies cannot recycle all types and amounts of generated plastic waste. Pyrolysis can convert these municipal mixed plastic streams into products with significant calorific value, which are likely to be used as energy sources. The present work describes a technology used to expand the portfolio of technical approaches to drive plastics circularity, i.e., thermochemical recycling. A base case scenario considered a capacity of 1.000 kg/h of municipal plastic waste, consisting of a mixture of polypropylene (PP), polystyrene (PS), polyethylene (PE), and plastic associated with paper, which were converted into non-condensable gases, oil, and char through a pyrogasification system. Based on mass and energy balances and experimental data from the literature, a total of 199.4 kg (48 MJ/kg) of liquid fuel and 832.85 kg (16 MJ/kg) of gas could be obtained with no need for external heating sources. The thermal requirement for the pyrolysis of 1.000 kg of municipal plastic waste (1.316 MJ) was supplied by the gasification of a fraction of the produced pyrolysis oil and gases. This feasibility analysis confirmed the technical adequacy of the proposed technology, which that will be further complemented by a technoeconomic study of the proposed solution.

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Plastic pyrolysis over HZSM-5 zeolite and fluid catalytic cracking catalyst under ultra-fast heating

Cited by 44 publications

References 63 publications

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics

Novel Staged Free-Fall Reactor for the (Catalytic) Pyrolysis of Lignocellulosic Biomass and Waste Plastics

Two-Stage Fixed-Bed Low-Density Polyethylene Pyrolysis: Influence of Using Different Catalytic Materials in the Second Stage

Municipal Plastic Waste Recycling through Pyrogasification

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