Conversion of sulfur during pressurized pyrolysis and gasification of black liquor with direct causticization using titanates

Artikel i vetenskaplig tidskrift, 2005

The release of sulfur during gasification and pyrolysis of black liquor in the presence of sodium titanates was investigated using a pressurized, entrained-flow reactor. The reaction conditions were temperatures of 900°C, 950°C and 1000°C, at pressures of 0.5 MPa and 1 MPa and in atmospheres of pure N2 or N2 with 2% CO2. Conversion of up to 35% of the sulfur in black liquor to gases was obtained within 5 seconds at these conditions. More of the sulfur in black liquor was converted to gases when CO2 was present than when not. More of both H2S and COS were produced in the presence of CO2 than in pure N2. Very little CS2 was produced in either case. The fraction of the sulfur in black liquor that was volatilized did not vary significantly with gasification pressure.