Liquid 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 several feed material such as wood-chips, straw and cellulose fibers were 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 of the flux and the 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.

The product yield was determined. Figure 1 shows the summary of water and liquid CHO-products formed during pyrolytic degradation of several feed material.

Figure 1: Formation of liquid products by liquid phase pyrolysis

Figure 2 shows the yield of fingerprint products generated by liquid-phase pyrolysis of different feed material.

Figure 2: Formation of condensible fingerprint products of liquid phase pyrolysis

The amount of condensibles does not differ dramatically for different feed material. Degradation of cellulose is seemingly controlled by cleavage plus dehydration while ligno-cellulosic feed leads to significant formation of methoxy-substituted phenols.