Characterization of the waxes obtained by the pyrolysis of polyolefin plastics in a conical spouted bed reactor

Arabiourrutia, Miriam; Elordi, Gorka; López, Gartzen; Borsella, E.; Bilbao, Javier; Olazar, Martı́n

doi:10.1016/j.jaap.2011.12.012

Cited by 222 publications

(130 citation statements)

References 40 publications

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“…The yields of waxes obtained from the HDPE pyrolysis are similar to those obtained from the LDPE pyrolysis, while the yields obtained from the PP pyrolysis are higher, especially at low temperatures [24]. This result can be explained as a consequence of the more branched structure of polypropylene, compared to that of polyethylenes.…”

Section: Pyrolysissupporting

confidence: 56%

Pyrolysis of Polyolefins in a Conical Spouted Bed Reactor: A Way to Obtain Valuable Products

Arabiourrutia¹,

Elordi²,

Olazar³

et al. 2017

Pyrolysis

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The amount of waste plastic increases every single year, which causes a critical environmental issue. Polyolefins (mainly high-and low-density polyethylene and polypropylene) are the most common types of plastics, accounting for 60 wt% of the plastic waste. Pyrolysis, the thermal degradation in an inert atmosphere, is considered to be one of the most appealing technologies for the recycling of plastic materials. The conical spouted bed reactor is suitable for the pyrolysis of plastic waste due to its ability to avoid agglomeration problems that may be caused by the melted plastic. The pyrolysis process may be carried out at different temperatures and with or without the presence of catalysts in the reaction environment in order to streamline product distribution. The resulting products are hydrocarbons: non-condensable gases (C 1 -C 4 ), gasoline fraction, diesel fraction, and waxes. These fractions might be used directly as feed streams for refinery units or as pools to be mixed with other streams from refineries.

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Section: Pyrolysissupporting

confidence: 56%

Pyrolysis of Polyolefins in a Conical Spouted Bed Reactor: A Way to Obtain Valuable Products

Arabiourrutia¹,

Elordi²,

Olazar³

et al. 2017

Pyrolysis

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show abstract

“…A detailed characterization of the waxes can be found elsewhere. 46 The yield of the remaining products obtained (nonaromatic C 5 −C 11 hydrocarbons, light olefins and alkanes) is very low and, furthermore, they may be upgraded by cracking, except methane and aromatics. Consequently, the volatiles formed in this first pyrolysis step are suitable for a further upgrade to light olefins by catalytic cracking.…”

Section: Resultsmentioning

confidence: 99%

Cracking of High Density Polyethylene Pyrolysis Waxes on HZSM-5 Catalysts of Different Acidity

Artetxe

López

Amutio

et al. 2013

Ind. Eng. Chem. Res.

188

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High density polyethylene (HDPE) cracking has been carried out in a thermal-catalytic two-step unit for the selective production of light olefins. Continuous pyrolysis of HDPE has been conducted in a conical spouted bed reactor at 500°C, and the volatiles formed (mainly waxes) have been transformed in a downstream fixed bed catalytic reactor at 500°C. The effect of catalyst acidity on product yield and composition has been studied by using three catalysts based on HZSM-5 zeolites with a SiO 2 /Al 2 O 3 ratio of 30, 80, and 280. The maximum light olefin yield (58 wt %) has been obtained using the most acidic catalyst (SiO 2 /Al 2 O 3 ratio of 30), with the individual yields of ethylene, propylene, and butenes being 9.5, 32, and 16.5 wt %, respectively. The results are a clear evidence of the higher efficiency of the two-step reaction system compared to the in situ catalytic pyrolysis (single-step), which is explained by the suitable combination of operating conditions in each one of the steps.

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“…21 A complete characterization of the waxes obtained in the continuous pyrolysis of HDPE in a CSBR is described elsewhere. 45 It should be noted that the remaining main products, i.e., C 12 − C 20 hydrocarbons (25.64 wt %) and light olefin and alkane fractions, can be upgraded by cracking, whereas the cracking refractory products (methane and aromatics) have a very low yield. Consequently, the product stream obtained in the first step has a suitable composition for the production of lighter hydrocarbons by downstream thermal cracking.…”

Section: Resultsmentioning

confidence: 99%

Production of Light Olefins from Polyethylene in a Two-Step Process: Pyrolysis in a Conical Spouted Bed and Downstream High-Temperature Thermal Cracking

Artetxe

López

Elordi

et al. 2012

Ind. Eng. Chem. Res.

124

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A two-step process has been used for the selective production of light olefins by the thermal cracking of highdensity polyethylene. The plastic has been continuously fed into a conical spouted-bed reactor (CSBR) operating at 500°C, which yields 93 wt % of waxes (C 21+ ) and C 12 −C 21 hydrocarbons. The volatile product stream has been cracked downstream in a multitubular (quartz tubes) reactor in the 800−950°C range, with short residence times (0.016−0.032 s). A yield of 77 wt % of light olefins (C 2 −C 4 ) has been obtained by operating at 900°C in the second step. The maximum yields of ethylene, propylene, and butenes are 40.4, 19.5, and 17.5 wt %, respectively. Given the short residence time of the products in the reactor, the yield of aromatics is only 6.2 wt %. The high light olefin yield is due to the excellent performance of both steps. The CSBR allows maximizing the yield of waxes and avoiding defluidization problems. The operating conditions in the multitubular reactor (low concentration of the compounds in the volatile stream and short volatile residence times) are suitable for minimizing secondary reactions.

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Characterization of the waxes obtained by the pyrolysis of polyolefin plastics in a conical spouted bed reactor

Cited by 222 publications

References 40 publications

Pyrolysis of Polyolefins in a Conical Spouted Bed Reactor: A Way to Obtain Valuable Products

Pyrolysis of Polyolefins in a Conical Spouted Bed Reactor: A Way to Obtain Valuable Products

Cracking of High Density Polyethylene Pyrolysis Waxes on HZSM-5 Catalysts of Different Acidity

Production of Light Olefins from Polyethylene in a Two-Step Process: Pyrolysis in a Conical Spouted Bed and Downstream High-Temperature Thermal Cracking

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