Molten salt pyrolysis of milled beech wood using an electrostatic precipitator for oil collection

Abstract

A tubular electrostatic precipitator (ESP) was designed and tested for collection of pyrolysis oil in molten salt pyrolysis of milled beech wood (0.5-2 mm). The voltage-current (V-I) characteristics were studied, showing most stable performance of the ESP when N2 was utilized as inert gas. The pyrolysis experiments were carried out in FLiNaK and (LiNaK)2CO3 over the temperature range of 450-600 ℃. The highest yields of pyrolysis oil were achieved in FLiNaK, with a maximum of 34.2 wt% at 500 ℃, followed by a decrease with increasing reactor temperature. The temperature had nearly no effect on the oil yield for pyrolysis in (LiNaK)2CO3 (19.0-22.5 wt%). Possible hydration reactions and formation of HF gas during FLiNaK pyrolysis were investigated by simulations (HSC Chemistry software) and measurements of the outlet gas (FTIR), but no significant amounts of HF were detected.

Keywords

• beech wood
• pyrolysis
• molten salts
• electrostatic
• precipitator