(177b) In-Situ and Ex-Situ Upgrade of Pyrolysis Vapors from Beetle-Killed Trees

In the western United States, around 42 million acres of conifer forests have been infested by bark beetles since 1996 and this number is expected to increase in the near future. This high level of tree mortality caused by bark beetle epidemic has already negatively impacted public benefits from forests; therefore, beetle-killed trees should be properly disposed of. However, some undesirable properties (e.g. bluish discoloration and cracking) of beetle-killed trees limit their applications for solid wood and wood panel manufacturing. Nevertheless, low moisture content and therefore high energy content make beetle-killed trees attractive feedstocks for fast pyrolysis. Our previous research showed that the decay stages of beetle-killed lodgepole pine (Pinus contorta) did not significantly affect the performance of both non-catalytic and catalytic fast pyrolysis, indicating fast pyrolysis is a promising way to convert beetle-killed trees into high-value chemicals and fuels. In the presence of HZSM-5, most oxygenated compounds were converted into aromatic hydrocarbons. Depending on the method of contact between catalyst and pyrolysis vapors, the upgrade progress can be classified into in-situ and ex-situ. In the in-situ process, the pyrolysis and upgrade take place in the same reactor, thus likely reducing the capital and operational costs. Whereas, the ex-situ process catalyzes pyrolysis vapors in a secondary reactor and allows more control over the vapor phase reactions and additional flexibility on the reactor configuration. For example, the ex-situ upgrade is more suitable for certain reactor types (e.g. auger pyrolyzer and ablative pyrolyzer) that are usually used in the mobile units to carry out pyrolysis of forest residues. Currently, there is limited understanding on the differences between these two upgrade methods. In this talk, we will report a comparison of in-situ and ex-situ upgrade processes for pyrolysis vapors derived from beetle-killed lodgepole pine. Both processes will be conducted using a micro-reactor, with the ex-situ process including a secondary catalytic reactor. Non-condensable gaseous and volatile products will be analyzed using GC/TCD and online GC/MS/FID, respectively. The effects of pyrolysis temperature, catalysis temperature, and catalyst-to-biomass ratios on the product yield and selectivity will be investigated.