Leaching as a pretreatment process to complement torrefaction in improving co-firing characteristics of Jatropha curcas seed cake

The presence of certain inorganic elements in biomass causes issues such as slagging, fouling and corrosion when co-firing with coal for power generation. In this work, the efficacy of leaching to remove these elements from Jatropha curcas seed cake was investigated. Leaching of both untorrefied and torrefied seed cakes was carried out in Milli-Q water at temperatures of 20, 35 and 50 °C. At 20 °C, the two critical elements, potassium and chlorine, decreased by as much as 85 and 97 %, respectively. Leaching at higher temperatures was only beneficial for the more intensely torrefied biomass, since they were more resistant to leaching. The electrical conductivity and ion content of the leachates were measured, as were the inorganic elemental content, dry ash content, volatile matter content and higher heating value (HHV) of the solid seed cake. A secondary benefit of the leaching was an increase in the HHV by up to 10 %

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

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\ub0C, 950\ub0C and 1000\ub0C, 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