Characteristics of polyethylene cracking in supercritical water compared to thermal cracking

Moriya, Tsuyoshi; Enomoto, Heiji

doi:10.1016/s0141-3910(99)00026-9

Cited by 133 publications

(111 citation statements)

References 17 publications

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“…Very recently, SCWO 54),55) was introduced as an important application of reactions in hydrothermal systems (water at hightemperature and pressure). However, most previous studies on SCWO have focused only on heteroatomcontaining organic compounds 56) . Vogelaar et al 57) and Katritzky et al 58) 61) revealed that the effect of SCW on desulfurization of oil is marginal.…”

Section: Upgrading Heavy Oil Using Scwmentioning

confidence: 99%

Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

Mandal¹,

Goto

Sasaki

2014

J. Jpn. Petrol. Inst.

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Heavy oils require substantial cracking in order to be economically refined to produce usable products. One major problem affecting the economics of refining heavy oils is the metal compounds contained in many of these oils which poison the catalyst used to crack the oil. Demetallization methods include physical, chemical, electrochemical, catalytic and supercritical water (SCW) techniques. Few of these methods are viable and/or efficient for the demetallization of heavy oil. This paper discusses the SCW based demetallization process by reviewing the open literature. The potential benefits of SCW based demetallization of heavy oils are also explored. Water partial pressure (WPP) has a moderate effect on the reaction of metalloporphyrins (MPs) in SCW; but temperature has a remarkably high effect. Metal removal is sensitive to the conversion of MP and increases exponentially with higher conversion. The kinetics are consistent with first-order dependency on MP disappearance. The reaction mechanism can be explained in terms of the free radical mechanism, but additional experiments and analysis are required to understand the fate of the metal after reaction. This non-catalytic SCW based upgrading process has the potential to allow production of refined fuel from heavy oils.

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Section: Upgrading Heavy Oil Using Scwmentioning

confidence: 99%

Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

Mandal¹,

Goto

Sasaki

2014

J. Jpn. Petrol. Inst.

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“…Figure 2a shows clearly that yields of the gas components changed dramatically between the non-catalytic and catalytic tests as well as among the catalytic tests. In the non-catalytic tests, C2-C4 hydrocarbon gases dominated the gas products as a result of thermal pyrolysis of the plastic [4][5][20][21]. Similar yields of hydrocarbon gases are obtained from conventional pyrolysis of LDPE [22].…”

Section: Solid Analysismentioning

confidence: 96%

“…The product gas sampled at room temperature was analysed using a system of gas chromatographs [20]. The analysis results were obtained in volume % and converted to moles or mass using the ideal gas equation and Henry's law.…”

Section: Gas Analysismentioning

confidence: 99%

Catalytic supercritical water gasification of plastics with supported RuO2: A potential solution to hydrocarbons–water pollution problem

Onwudili

Williams

2016

Process Safety and Environmental Protection

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ABSTRACT:Here we report on a potential catalytic process for efficient clean-up of plastic pollution in waters, such as the Great Pacific Garbage Patch (CPGP). Detailed catalytic mechanisms of RuO2 during supercritical water gasification of common polyolefin plastics including low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polystyrene (PP), have been investigated in a batch reactor at 450 °C, 60 min. All four plastics gave very high carbon gasification efficiencies (CGE) and hydrogen gasification efficiencies (HGE). Methane as the highest gas component, with a yield of up to 37 mol kg -1 LDPE using the 20 wt% RuO2 catalyst. Evaluation of the gas yields, CGE and HGE revealed that the conversion of PS involved thermal degradation, steam reforming and methanation; whereas hydrogenolysis was a possible additional mechanism during the conversion of aliphatic plastics. The process has the benefits of producing a cleanpressurized methane-rich fuel gas as well as cleaning up hydrocarbons-polluted waters.

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“…Moriya and Enomoto [117] investigated the degradation of PE in supercritical water. The reaction proceeded more slowly in the initial stage than during thermal degradation.…”

Section: Chemolysis and Solvent Processesmentioning

confidence: 99%

Feedstock recycling of waste polymeric material

Grause

Buekens

Sakata

et al. 2011

J Mater Cycles Waste Manag

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The first International Symposium on Feedstock Recycling of Polymeric Materials (ISFR) was hosted in 1999 in Sendai, Japan. Since then, the ISFR has been held five times in different places in Asia and Europe. Each of these conferences focused on special issues covered by the Journal of Material Cycles and Waste Management. The topics included thermal processes with and without catalysts, wet processes in various solvents, the dehydrochlorination of PVC, mechanical recycling and separation techniques, as well as the treatment of biomaterials. This review is a compilation of the most interesting and important developments discussed at the ISFR during the last decade.

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Characteristics of polyethylene cracking in supercritical water compared to thermal cracking

Cited by 133 publications

References 17 publications

Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

Removal of Nickel and Vanadium from Heavy Oils Using Supercritical Water

Catalytic supercritical water gasification of plastics with supported RuO2: A potential solution to hydrocarbons–water pollution problem

Feedstock recycling of waste polymeric material

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