TheoreticalanalysisofmasstransferandreactioninaporousmediumappliedtothegasificationofgraphitebywatervaporOriginalResearchArticle

Thetheoriesofmasstransferandreactioninporousmediumwereappliedtoinvestigatethegasificationofgraphitebywatervaporinreactor.Basedonseverallogicalassumptions,thegasificationofgraphitebywatervaporwasinvestigated.Differentshapesofgraphitewereanalysed:semi-infiniteblocks,planksandcylinders.Analysisrevealsthatthereactionratevarieswiththelocation,whichcanexplaintheintensegasificationthatoccursatupstreamduringexperiments.Thetemperaturedependenceofthereactionrateexpresseddifferentranges.Atlowtemperatures,thereactionratesdependgreatlyonthereactiontemperature,andtheinfluenceofshapeismorepronounced.Athightemperatures,thedependenceweakensduetothelimitofgastransfer,andtheinfluenceofshapedisappears.Thewatervaporpressureatexteriorsurfacedecreaseswithtemperature,butthepressuregradients(bothinsideandoutsideofporousmedia)increaseswithtemperature.Fortheplatelikeandcylindricalporousmedia,thereactionratedecreaseswiththethicknessorradiusbecauseoftheincreaseinspecificsurface.Whenthepenetratingdepthofwatervaporislargerthanthehalf-thicknessorradiusofporousmedia,thewatervaporwouldcumulateinporousmediasothatthepressureofreactinggasincreases.