Direct liquefaction of wood with aqueous HI solution to a wood oil product under low severity conditions, atmospheric pressure and low temperature around 125°C, was investigated in two stages. The first stage involved batch reactor studies. The wood-HI liquefaction reaction is fast, nearly complete in as little as 20s when the initial aqueous phase concentration is 57 wt% HI or greater. Yield of the char-type residue, a major problem in other liquefaction processes, is completely eliminated provided the final aqueous phase concentration is 50 wt% HI or above. The performance of this process with wood is better than would be predicted from experiments on the liquefaction of wood components determined separately. / Removal of oxygen from polymeric wood components is accomplished with oxidation of I- to I2. The second stage tested a novel concept for closing the HI → I2 → HI loop, an electrochemical liquefaction reactor (ECLR) with liquefaction in the cathode cell where I2 is simultaneously reduced back to I- . Electrolysis of water at the anode generates O2 and the H+ required at the platinum cathode for HI regeneration. Without wood liquefaction, current efficiency for I2 reduction is 90--100% and I2 concentration can be maintained at about 0.1 M, which is about 10% of that without I2 reduction. / Preliminary ECLR tests in batch and batchwise-continuous modes demonstrated simultaneous wood liquefaction and electrochemical reduction of I2 in the presence of the viscous wood oil. Also the iodine content of the crude wood oil is thereby reduced by about 60%, where this limit is imposed by the strong physical association between I2 and various functional groups in the product. Generation of H2, the competitive reaction, can be avoided. / ECLR characteristics were determined from a continuous run in a sealed reactor at a steady aqueous phase concentration of 55 wt% HI with a cathode current density of 0.81 A/cm2 at a cell voltage of 6 V. Carbon base yields were 84.2% crude wood oil product, 4.9% methyl iodide from the lignin methoxy groups and no production of the char-type residue common to other biomass liquefaction processes. Of the I2 produced, 93% would be reduced to HI, the other 7% being I2 associated physically with the product. Of the H+ generated at the anode, about half is used for HI regeneration and half for electrochemical liquefaction reactions as reflected by the exceptionally high levels of hydrogen retention and oxygen removal of the wood oil relative to the wood, above 85% in both cases.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37693 |
| Date | January 1994 |
| Creators | Wang, Lijie, 1963- |
| Contributors | Douglas, W. J. M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001808617, proquestno: NQ70195, Theses scanned by UMI/ProQuest. |
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