Pyrolysis of biomass in a laboratory pyrolysis unit with a screw type reactor and a secondary decomposition reactor
Sustain. Environ. Res., 25(5), 261-266 (2015)
Dalibor Susa and Juma Haydary
Pyrolysis, wood biomass, secondary decomposition, catalyst, dolomite, RC
The current paper deals with experimental pyrolysis of wood biomass in a laboratory pyrolysis system with two reactors (a primary pyrolysis reactor and a secondary catalytic reactor). The effect of temperature (500-800 °C) and the addition of two mineral catalysts on the product yields, gas composition and tar reduction were investigated. In the second catalytic reactor, calcined dolomite and a red clay mineral material (marked as RC) were used as catalysts.
Solid residue was collected at the outlet of the first reactor and the liquid product was obtained after the condensation of vapors in a series of coolers. Total organic carbon in the liquid product was estimated by elemental analysis. Instantaneous concentrations of gaseous products were obtained under the experimental conditions and analyzed by gas chromatography. The main gaseous products were: carbon monoxide, methane, hydrogen, carbon dioxide and light hydrocarbons. In addition, gravimetric tar analysis of the product gas was performed to determine the heavy tar content in the outgoing gas.
The use of catalysts in the secondary reactor had a significant effect on the gas and tar yields. The results showed an increase in the total gas yield at higher temperatures, accompanied by a drop in the tar yield. RC demonstrated good effectiveness of tar reduction at low temperatures. However, at 700 °C, the tar content obtained using RC was 4.8 mg g-1 of the raw sample compared to 3.2 mg g-1 when using dolomite. This was significantly different to that obtained in the non-catalyst run, with 11.2 mg g-1 of the tar remaining.