科研之友
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摘要
CO2 acidification of Kraft black liquors was performed at temperatures of 100-150 degrees C and pressures of 5-8 bar in an investigation of the SLRP (TM) process. At these conditions, a highly hydrated, lignin-rich liquid (vs. the usual solid) separated out to form a new phase. The solids content/ionic strength of the starting black liquor was found to be a key variable for controlling the bulk and molecular properties of the "liquid-lignin" (LL) phase. For example, black liquors of lower ionic strengths (20% solids) produced LLs with lower ash contents and higher molecular weights, albeit in lower yields. In contrast, higher ionic strengths/solids content (40%) produced LLs in higher yields with higher aromatic and aliphatic hydroxyl contents. Temperature effects were significant only at the highest levels. The degree of hydration of the LL phase was found to be a useful measure of the water available for hydration of ionized/polarizable groups in lignin.
- 出版日期2015
