Fast pyrolysis in a novel wire-mesh reactor: design and initial results

Elly Hoekstra, Wim P.M. van Swaaij, Sascha R.A. Kersten, Kees J.A. Hogendoorn

Research output: Contribution to journalArticleAcademicpeer-review

31 Citations (Scopus)

Abstract

Pyrolysis is known to occur by decomposition processes followed by vapour phase reactions. The goal of this research is to develop a novel device to study the initial decomposition processes. For this, a novel wire-mesh reactor was constructed. A small sample (<0.1 g) was clamped between two meshes that were heated fast (up to 10 000 °C/s, ΔTmesh ±35 °C) by an electrical current. The mesh/feedstock was placed inside a vacumized (P < 0.3 mbar), liquid nitrogen cooled vessel (Twall < −80 °C). These two last features were proven to result in a low vapour life time (<15–25 ms versus ∼2 s in typical pyrolysis). The vapour residence time and temperature could be increased by increasing the pressure inside the reactor and by removing of the liquid nitrogen cooling. Reproducible results concerning yields (mass balance closures 90–110 wt%) and analysis were obtained (oil by SEC and NMR, gas by GC, char by FTIR). The yields and oil composition were changing with loading from 0.05 g to 0.1 g, despite the small sample amounts. Compared to more “conventional” pyrolysis processes, high oil yields (84 wt%), very low char yields (5 wt%) and low gas yields (8 wt%) were obtained. Using a high speed camera, movies were made and together with accompanying pressure profiles, it was possible to estimate the conversion rate. At 500 °C the conversion process was finished within 0.8 s which is faster than previously reported in the literature. Especially an increase in gas yield (+14 wt%, mainly CO) was observed in absence of cooling (Pvac/No Cooling), while both the gas (+4 wt%) and char yield (+3 wt%) increased under atmospheric pressure (Patm/Cooling), all at the expense of oil yield. Compared to more “conventional” pyrolysis oil, the oil did contain: (i) heavier molecules and (ii) a sugar fraction.
Original languageEnglish
Pages (from-to)45-58
Number of pages14
JournalChemical Engineering Journal
Volume191
DOIs
Publication statusPublished - 2012

Fingerprint

pyrolysis
Oils
Pyrolysis
Wire
Gases
Cooling
oil
Vapors
Liquid nitrogen
cooling
gas
Decomposition
High speed cameras
Carbon Monoxide
decomposition
Sugars
Feedstocks
Atmospheric pressure
liquid
reactor

Keywords

  • Industrial technology (see also 5311)Duurzame energiebronnen
  • Fast pyrolysis
  • Biomass
  • Novel wire-mesh reactor
  • Initial decomposition products

Cite this

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title = "Fast pyrolysis in a novel wire-mesh reactor: design and initial results",
abstract = "Pyrolysis is known to occur by decomposition processes followed by vapour phase reactions. The goal of this research is to develop a novel device to study the initial decomposition processes. For this, a novel wire-mesh reactor was constructed. A small sample (<0.1 g) was clamped between two meshes that were heated fast (up to 10 000 °C/s, ΔTmesh ±35 °C) by an electrical current. The mesh/feedstock was placed inside a vacumized (P < 0.3 mbar), liquid nitrogen cooled vessel (Twall < −80 °C). These two last features were proven to result in a low vapour life time (<15–25 ms versus ∼2 s in typical pyrolysis). The vapour residence time and temperature could be increased by increasing the pressure inside the reactor and by removing of the liquid nitrogen cooling. Reproducible results concerning yields (mass balance closures 90–110 wt{\%}) and analysis were obtained (oil by SEC and NMR, gas by GC, char by FTIR). The yields and oil composition were changing with loading from 0.05 g to 0.1 g, despite the small sample amounts. Compared to more “conventional” pyrolysis processes, high oil yields (84 wt{\%}), very low char yields (5 wt{\%}) and low gas yields (8 wt{\%}) were obtained. Using a high speed camera, movies were made and together with accompanying pressure profiles, it was possible to estimate the conversion rate. At 500 °C the conversion process was finished within 0.8 s which is faster than previously reported in the literature. Especially an increase in gas yield (+14 wt{\%}, mainly CO) was observed in absence of cooling (Pvac/No Cooling), while both the gas (+4 wt{\%}) and char yield (+3 wt{\%}) increased under atmospheric pressure (Patm/Cooling), all at the expense of oil yield. Compared to more “conventional” pyrolysis oil, the oil did contain: (i) heavier molecules and (ii) a sugar fraction.",
keywords = "Industrial technology (see also 5311)Duurzame energiebronnen, Fast pyrolysis, Biomass, Novel wire-mesh reactor, Initial decomposition products",
author = "Elly Hoekstra and {van Swaaij}, {Wim P.M.} and Kersten, {Sascha R.A.} and Hogendoorn, {Kees J.A.}",
year = "2012",
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language = "English",
volume = "191",
pages = "45--58",
journal = "Chemical Engineering Journal",
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}

Fast pyrolysis in a novel wire-mesh reactor : design and initial results. / Hoekstra, Elly; van Swaaij, Wim P.M.; Kersten, Sascha R.A.; Hogendoorn, Kees J.A.

In: Chemical Engineering Journal, Vol. 191, 2012, p. 45-58.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Fast pyrolysis in a novel wire-mesh reactor

T2 - design and initial results

AU - Hoekstra, Elly

AU - van Swaaij, Wim P.M.

AU - Kersten, Sascha R.A.

AU - Hogendoorn, Kees J.A.

PY - 2012

Y1 - 2012

N2 - Pyrolysis is known to occur by decomposition processes followed by vapour phase reactions. The goal of this research is to develop a novel device to study the initial decomposition processes. For this, a novel wire-mesh reactor was constructed. A small sample (<0.1 g) was clamped between two meshes that were heated fast (up to 10 000 °C/s, ΔTmesh ±35 °C) by an electrical current. The mesh/feedstock was placed inside a vacumized (P < 0.3 mbar), liquid nitrogen cooled vessel (Twall < −80 °C). These two last features were proven to result in a low vapour life time (<15–25 ms versus ∼2 s in typical pyrolysis). The vapour residence time and temperature could be increased by increasing the pressure inside the reactor and by removing of the liquid nitrogen cooling. Reproducible results concerning yields (mass balance closures 90–110 wt%) and analysis were obtained (oil by SEC and NMR, gas by GC, char by FTIR). The yields and oil composition were changing with loading from 0.05 g to 0.1 g, despite the small sample amounts. Compared to more “conventional” pyrolysis processes, high oil yields (84 wt%), very low char yields (5 wt%) and low gas yields (8 wt%) were obtained. Using a high speed camera, movies were made and together with accompanying pressure profiles, it was possible to estimate the conversion rate. At 500 °C the conversion process was finished within 0.8 s which is faster than previously reported in the literature. Especially an increase in gas yield (+14 wt%, mainly CO) was observed in absence of cooling (Pvac/No Cooling), while both the gas (+4 wt%) and char yield (+3 wt%) increased under atmospheric pressure (Patm/Cooling), all at the expense of oil yield. Compared to more “conventional” pyrolysis oil, the oil did contain: (i) heavier molecules and (ii) a sugar fraction.

AB - Pyrolysis is known to occur by decomposition processes followed by vapour phase reactions. The goal of this research is to develop a novel device to study the initial decomposition processes. For this, a novel wire-mesh reactor was constructed. A small sample (<0.1 g) was clamped between two meshes that were heated fast (up to 10 000 °C/s, ΔTmesh ±35 °C) by an electrical current. The mesh/feedstock was placed inside a vacumized (P < 0.3 mbar), liquid nitrogen cooled vessel (Twall < −80 °C). These two last features were proven to result in a low vapour life time (<15–25 ms versus ∼2 s in typical pyrolysis). The vapour residence time and temperature could be increased by increasing the pressure inside the reactor and by removing of the liquid nitrogen cooling. Reproducible results concerning yields (mass balance closures 90–110 wt%) and analysis were obtained (oil by SEC and NMR, gas by GC, char by FTIR). The yields and oil composition were changing with loading from 0.05 g to 0.1 g, despite the small sample amounts. Compared to more “conventional” pyrolysis processes, high oil yields (84 wt%), very low char yields (5 wt%) and low gas yields (8 wt%) were obtained. Using a high speed camera, movies were made and together with accompanying pressure profiles, it was possible to estimate the conversion rate. At 500 °C the conversion process was finished within 0.8 s which is faster than previously reported in the literature. Especially an increase in gas yield (+14 wt%, mainly CO) was observed in absence of cooling (Pvac/No Cooling), while both the gas (+4 wt%) and char yield (+3 wt%) increased under atmospheric pressure (Patm/Cooling), all at the expense of oil yield. Compared to more “conventional” pyrolysis oil, the oil did contain: (i) heavier molecules and (ii) a sugar fraction.

KW - Industrial technology (see also 5311)Duurzame energiebronnen

KW - Fast pyrolysis

KW - Biomass

KW - Novel wire-mesh reactor

KW - Initial decomposition products

U2 - 10.1016/j.cej.2012.01.117

DO - 10.1016/j.cej.2012.01.117

M3 - Article

VL - 191

SP - 45

EP - 58

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

SN - 1385-8947

ER -