In Situ and ex Situ Catalytic Pyrolysis of Pine in a Bench-Scale Fluidized Bed Reactor System

Maarit Iisa, Richard French, Kellene Orton, Matthew Yung, David Johnson, Mark Nimlos, Jeroen Dam, Michael Watson

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107 Scopus Citations

Abstract

In situ and ex situ catalytic pyrolysis were compared in a system with two 2-in. bubbling fluidized bed reactors. Pine was pyrolyzed in the system with a catalyst, HZSM-5 with a silica-to-alumina ratio of 30, placed either in the first (pyrolysis) reactor or the second (upgrading) reactor. Both the pyrolysis and upgrading temperatures were 500 °C, and the weight hourly space velocity was 1.1 h-1. Five catalytic cycles were completed in each experiment. The catalytic cycles were continued until oxygenates in the vapors became dominant. The catalyst was then oxidized, after which a new catalytic cycle was begun. The in situ configuration gave slightly higher oil yield but also higher oxygen content than the ex situ configuration, which indicates that the catalyst deactivated faster in the in situ configuration than the ex situ configuration. Analysis of the spent catalysts confirmed higher accumulation of metals in the in situ experiment. In all experiments, the organic oil mass yields varied between 14 and 17% and the carbon efficiencies between 20 and 25%. The organic oxygen concentrations in the oils were 16-18%, which represented a 45% reduction compared to corresponding noncatalytic pyrolysis oils prepared in the same fluidized bed reactor system. GC/MS analysis showed the oils to contain one- to four-ring aromatic hydrocarbons and a variety of oxygenates (phenols, furans, benzofurans, methoxyphenols, naphthalenols, indenols). High fractions of oxygen were rejected as water, CO, and CO2, which indicates the importance of dehydration, decarbonylation, and decarboxylation reactions. Light gases were the major sources of carbon losses, followed by char and coke.

Original languageAmerican English
Pages (from-to)2144-2157
Number of pages14
JournalEnergy and Fuels
Volume30
Issue number3
DOIs
StatePublished - 17 Mar 2016

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

NREL Publication Number

  • NREL/JA-5100-64977

Keywords

  • catalytic pyrolysis
  • HZSM-5
  • pine
  • vapor phase upgrading

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