Effect Of Minerals On Transformation Of Nitrogen During Coal Pyrolysis/Gasification

In this paper, it is discussed that the effect of several factors on the transformation of nitrogen during coal pyrolysis and gasification. The coal sample in reactor was heated with two kinds of fashion ?slow heating rate by temperature-programmed and fast heating rate. The factors concerned are temperature, coal type, inherent minerals and adscititious Fe. Moreover, not only the yield and distribution of nitrogen from coal in gas and solid products, but also the state of adscititious Fe are analyzed with modern analytic instruments, such as 1C, XRD, element analyzer and so on.Some useful results and conclusions are acquired (obtained) as fallowings:1) Minerals in coal play an important role in the formation of HCN and NH3. During temperature program pyrolysis not only the yield of NH3 from demineralized coal is less than that from raw coal, but also it changes with ash matter in coals; On the other hand, HCN formation have relation with composition and stateof inherent minerals, coal rank is also one of key factors which affect HCN formation.2) Minerals in coal react mainly on the initial devolatilization. The yields of HCN and NH3 from Pingshuo demineralized coal is less than that from raw coal at contant temperature during pyrolysis, it increases with an increase in temperature.3) Ash obtained by coal combustion in raw coal can promote the release of HCN and NHs obviously and increase nitrogen retention in char during pyrolysis, but ash added in demineralized coal has different action. The react mechanism is different for raw coal and demineralized coal and ash may change the distribute profile of coal nitrogen in a degree.4) Pingshuo raw coal with Fe can decrease the realease of NH3 during temperature programmed pyrolysis, And content of 0.2% - 0.5 % (wt) Fe have better catalytic effect; Pingshuo raw coal with Fe can decrease the realease of HCN and NH3 at contant temperature, these results are affected by synergetic action of minerals in coal and adscititious Fe.5) Formation of NHs is mainly from the conversion of char-N during steam gasification, this result is independent of coal type.6) Inherent minerals can suppress NH3 formation and promote HCN formation for Pingshuo coal and it can change the distribute profile of coal nitrogen in a degree during steam gasification;Adscititious Fe can decrease the release of HCN and NH3 in thisprocess.7) a -Fe, FeO(OH) and FeO are the state for adscititious Fe in coal that can affect the transformation of nitrogen during coal pyrolysis. Various Fe state affect the forms of nitrogenous species in different degree; Fe3O4 is the main state of Fe in char obtained by CO2/H2O gasification.