Liquid and Solid Products of Liquid Phase-Pyrolysis

Ligno-cellulosic feed is expected to contribute significantly to production of liquified combustibles in future, because of the quantity and the variety of feed material. Therefore the pyrolytic degradation properties of wood and its building blocks glucose and cellulose were investigated. The interaction between heat carrier, biomass and biomass products in the condensed liquid and vapour phase was investigated. The process was carried out in a semi-batch reaction vessel under isothermal conditions at a temperature of T = 623 K and at ambient pressure. For optimum heat transfer the pyrolysis process was carried out in liquid carrier phase. Gaseous products as well as condensibles were removed on top of the reaction vessel. Condensation temperature was T = 20 °C. After recording flux and composition the gaseous phase was incinerated in a flare. The condensed products were analysed by GC-MS and NMR spectroscopy as well as elemental analysis (CHNO). The solid product residues were pretreated by solid-liquid extraction and afterwards analyzed by elementary analysis, FTIR-ATR, Raman spectroscopy, scanning electron microscope and energy dispersive X-ray spectroscopy. Several operation parameters were investigated. Representatively the effect of particle size is briefly mentioned. Figure 1 shows the effect of feed particle size on the amount of CHO-products and the amount of water formed by thermal dehydration of softwood. Following the results shown in Figure 1 variation of particle size does not have an effect on the amount of liquid CHO-products when pyrolysing softwood. Water formation decreases for feed particles of smaller particle size. As shown in Figure 1 the total amount of liquid CHO-products seems to be constant and independent of the feed particle size. The chemical composition of liquid phase pyrolysis products differs. Based on the detailed mass balance the effect of operation parameters on pyrolytic degradation of softwood, product formation and energy balance was determined.