| Gasification of biomass represents a potentially efficient way to use biomass as arenewable energy source.The gas quality is poor and low of heat value when gasificationbiomass like straw.The addition of plastics to biomass increased value of gas, stabilized thegas of co-gasification. Biomass contains significant higher amounts of alkali metals, it’sprone to volatilize and play catalytic role in gasification process, On the other side lead toserious problems such as slagging, agglomeration,deposition and heated side corrosion.Andthe behavior of alkali metals during the co-gasification plays an important role in solvingabove problems.The paper predicted the effect on temperature of the behavior of alkali metals during theco-gasification of biomass and plastics using the thermodynamic equilibrium state. The resultshows that the alkali chlorides are the main components in gas phase and the alkali silicate,alkali aluminosilicate are the main components in solid phase during the co-gasification ofbiomass and PE.The alkali chlorides would be least if the temperature is controlled at700centigrade. The concentration of equilibrium is the0.01mol-%of alkali chlorides, and5.3mol-%of solid phase.On the base of chemical thermal equilibrium calculation, the migration behavior of alkalimetals during co-gasification of biomass and mixfuels in a fixed bed was studied on the X-raypower diffraction and scanning electron microscope/energy dispersive spectrometer atdifferent temperatures and different pecentages. The results indicated that the alkali chloridesare the main components in gaseous and the release radio enlarge with the increase of thetemperature.Ash just has alkali carbonate, sulphate, silicate, aluminosilicate above800centigrade.Cause of a large amouts of C and H in the fules with the mixed of plstic PE thatmakes the ability of deposition stronger and easily produced K2CO3. Moreover the morepercentages of PE in mixfules, the stronger deposition ability of K.The release radio of K is10.86%during co-gasification lower than gasifiction cornstalk which is release radio of K is 23.97%. The release radio of K is5.19%during co-gasification cornstalk and PVC that lowerthan co-gasification cornstalk and PE.So mass of Cl can decreased the release radio of K andincreased the radio in ash of mixfuels to produced KCl, KClO3.The release of radio of alkali metals was analyzed by gray association degree theory indifferent C/H, Cl/K, Cl/Na amolar ratio and different gasification temperature. The resultsshow that C/H molar ratio is the most important element. |
