مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

Improved alkali resistant refractories are needed for biomass and black liquor gasification (BBLC) . One particular ly harsh application is linings for gasifiers used in the treatment of black liquor (BL). Bla ck liquor is a water solution ofthe non-cellulose portion of the wood (mainly lignin) and the spent pulping chemicals (Na]COj. K]COj. and Na]S). Development ofnew refractory materials for the black liquor gasification (BLC) application is a critical issue for implementation of this technology. FactSage® thermodynamic sof tware was used to analyze the phas es present in BL smelt and to predict the interaction of BL smelt with different refractory compounds. The modeling included prediction of the phases f ormed under the operating conditions of high temperature black liquor gasification (BLC) process. At the operating temperature ofthe BLG. FactSage® predicted that the water would evaporate from the BL and that the organic portion of BL would combust. leaving a black liquor smelt composed of sodium carbonate (70-75%). potassium carbonate (2-5%). and sodium sulfide (20-25%). Exposure of aluminosilicates to this smelt leads to significant corrosion due to f ormat ion of expansive phases with subsequent cracking and spalling. Oxides (21י0]. CeO]. La]O;. YeO}. Li]O. MgO and CaO) were determined to be resistant to black liquor smelt but non-oxides (SiC and Si jN4) would oxidize and dissolve in the smelt. The other candidates such as MgAI]04 and BaAI]04 were resistant to sodium carbonate but not to potassium carbonate. LiAIO] was stable with both sodium carbonate and potassium carbonate. Candidate materials selected on the basis of the thermodynamic calculations are being tested by sessile drop test for corrosion resistance to molten black liquor smelt . Sessile drop testing has confirmed the thermodynamic predi ctions fo r AI]Oj. CeO]. MgO and CaO. Sessile drop testing showed that the thermodynamic predictions were incorrect for 21י0].