Effect Of Internal Inorganic Matters On Pyrolysis Of Biomass

This paper focused on the pyrolysis process of biomass on the fixed-bed reactor and the effect of internal inorganic matters on the products distribution, products compositions as well as on the decomposition of each fiber constituent in biomass. Rice straw and pine wood (PW) were selected and analyzed by using water or acid washing method, fiber constituent analyses and so on. This paper included the following parts:Firstly, there were evident differences in internal metals and organic matters between rice straw (RS), water-washed rice straw (WRS) and acid-washed rice straw (ARS). It was found that water removed most alkali metals (K and Na); whereas acid removed more alkali and alkali earth metals (K, Na, Ca and Mg). Either the water washing or the acid washing removed a portion of NDS but virtually unaffected the constituents of hemi cellulose, cellulose and lignin in RS. The differences in the product distribution and constituents between RS, WRS and ARS were influenced by both the internal mineral metals and the changed organic matter. Either WRS or ARS produced slightly more liquid product and less gaseous product than RS. The differences in the char yield between RS, WRS and ARS were changed with pyrolysis temperature. Meanwhile, it was revealed that the internal metals played a catalytic role in the promoted decomposition of each constituent of NDS, hemicellulose, cellulose and lignin in whole RS. However, calcium in RS and WRS appeared to prevent NDS and hemicellulose from decomposition at a lower temperature of 275℃. A conclusion also could be drawn that the char product was not a single carbon material. There existed NDS, "cellulose" and "lignin" in the chars.Secondly, the fiber constituents of chars obtained from RS were quite different from those from PW, which successfully proved the important effect of internal metals on the decomposition of hemicellulose, "cellulose" and "lignin". This paper also proved that the char obtained at low temperature mainly came from the decomposition of NDS, other than cellulose.