Hydrogen production from polystyrene pyrolysis and gasification: Characteristics and kinetics

Ahmed, Islam; Gupta, Ashwani K.

doi:10.1016/j.ijhydene.2009.05.046

Cited by 95 publications

(30 citation statements)

References 28 publications

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“…A lack of plot linearity and inconsistent activation energy values are observed and the authors conclude that simple first or second order models are good enough for determining the activation energy and, therefore, constitute "the most suitable design approach". Other works employing similar single-curve model-fitting kinetic procedures reached analogous conclusions (Ahmad et al , 2010, Ahmed and Gupta, 2009, Krishna and Pugazhenthi, 2011. However, some other works, employing isoconversional and non-linear model fitting methods, have revealed the unsuitability of nth order reaction models and suggest an acceleratory model instead (Chen et al , 2007, Sanchez-Jimenez et al , 2010, Snegirev et al , 2012, Vyazovkin et al , 2004.…”

Section: Introductionmentioning

confidence: 86%

Limitations of model-fitting methods for kinetic analysis: Polystyrene thermal degradation

Jiménez

Pérez‐Maqueda

Criado

2013

Resources, Conservation and Recycling

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Section: Introductionmentioning

confidence: 86%

Limitations of model-fitting methods for kinetic analysis: Polystyrene thermal degradation

Jiménez

Pérez‐Maqueda

Criado

2013

Resources, Conservation and Recycling

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“…Liu et al [19] found that increasing the decomposition temperature between 500 C and 700 C increased the yield of carbon nanotubes obtained, with a small dip in production tha that observed at 800 C. In terms of hydrogen production, a number of studies have found that raising the reaction temperature tends to result in an increase in the hydrogen yield obtained, as more hydrocarbons decompose [19,38,48,49]. When hydrogen and carbon nanotubes are produced simultaneously, increasing the temperature sees an increase in the yields of both, since hydrogen is produced during carbon deposition [19,50].…”

Section: Introductionmentioning

confidence: 99%

“…It is considered a green alternative to fossil fuels since its combustion gives off no carbon dioxide. Its production from thermal treatment of plastics is well established, with steam gasification proving a fruitful means of achieving large hydrogen yields [23,28,[38][39][40][41][42]. However in previous research by this research group it was found that whilst giving larger yields of hydrogen, adding steam to the thermal treatment of LDPE leads to a reduction in CNT yields [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of growth temperature and feedstock:catalyst ratio on the production of carbon nanotubes and hydrogen from the pyrolysis of waste plastics

Acomb

2015

Journal of Analytical and Applied Pyrolysis

129

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Carbon nanotubes have been produced from a low density polyethylene (LDPE) feedstock via a two stage pyrolysis process. The temperature of the second stage, where carbon deposition on an iron alumina catalyst occurs (growth temperature), was varied using catalyst temperatures of 700, 800 and 900 C. An increase in catalyst temperature led to a higher yield of both carbon nanotubes and hydrogen, as the rate of carbon deposition increased.Changing the amount of feedstock relative to the catalyst also had an effect on the production of both carbon nanotubes and hydrogen. As more feedstock is used a larger source of carbon gives rise to a larger amount of carbon nanotubes per gram of catalyst. However, in terms of the percentage of feedstock converted into carbon nanotubes and hydrogen gas, a reduction was observed. Conversion of plastic into carbon nanotubes was 29.1 wt.% when 0.5g LDPE was used, but reduced to 13.1 wt.% with 1.25g LDPE. This is because the catalyst activity reduces as it becomes overloaded, and much of the hydrocarbon gases are left unreacted. This gives an economic playoff between large conversion of plastics into carbon nanotubes and hydrogen gas, and large yields of carbon nanotubes per gram of catalyst used.

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“…Waste plastics are notoriously difficult to recycle, and thermal treatments such as pyrolysis can therefore offer an alternative waste management option to unsustainable landfill practices. Production of hydrogen from waste plastics is therefore a well-researched area, with a number of studies using pyrolysis and gasification techniques [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The use of different metal catalysts for the simultaneous production of carbon nanotubes and hydrogen from pyrolysis of plastic feedstocks

Acomb

Williams

2016

Applied Catalysis B: Environmental

233

120

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Nickel, iron, cobalt and copper catalysts were prepared by impregnation and used to produce carbon nanotubes and hydrogen gas from a LDPE feedstock. A two stage catalytic pyrolysis process was used to enable large yields of both products. Plastics samples were pyrolysed in nitrogen at 600°C, before the evolved gases were passed to a second stage and allowed to deposit carbon onto the catalyst at a temperature of 800°C. Carbon nanotubes were successfully generated on nickel, iron and cobalt but were barely observed on the copper catalyst. Iron and nickel catalysts gave the largest yield of both hydrogen and carbon nanotubes as a result of metal-support interactions which were neither too strong, like cobalts, nor too weak like copper. These metal support interactions proved a key factor in CNT production. A nickel catalyst with a weaker interaction was prepared using a lower calcination temperature. Yields of both carbon nanotubes and hydrogen gas were lower on the Ni-catalyst prepared at the lower calcination temperature, as a result of sintering of the nickel particles. In addition, the catalyst prepared at a lower calcination temperature produced metal particles which were too large for CNT growth, producing amorphous carbons which deactivate the catalyst instead. Overall the iron catalyst gave the largest yield of CNTs, which is attributed to both its good metal-support interactions and irons large carbon solubility.

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Hydrogen production from polystyrene pyrolysis and gasification: Characteristics and kinetics

Cited by 95 publications

References 28 publications

Limitations of model-fitting methods for kinetic analysis: Polystyrene thermal degradation

Limitations of model-fitting methods for kinetic analysis: Polystyrene thermal degradation

Effect of growth temperature and feedstock:catalyst ratio on the production of carbon nanotubes and hydrogen from the pyrolysis of waste plastics

The use of different metal catalysts for the simultaneous production of carbon nanotubes and hydrogen from pyrolysis of plastic feedstocks

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