IRANIAN BIOENERGY CONFERENCE | Year:2012 | دوره:3 |Papers Count:3

NOWADAYS STIRLING ENGINES ARE WIDELY USED IN BALTIC COUNTRIES. WIDESPREAD USAGE OF STIRLING ENGINES LED TO MANY INVESTIGATIONS ON ORGANIC DUST COMBUSTION TO ENHANCE THESE ENGINES EFFICIENCY. HOWEVER MANY EXPERIMENTAL STUDIES HAVE DONE IN THIS SUBJECT, BUT LACK OF AN INTEGRAL ANALYTICAL MODEL IS SENSIBLE. IN THIS STUDY WE PRESENT AN ANALYTICAL MODEL TO SIMULATE THE COMBUSTION PROCESS OF MOIST ORGANIC DUST. ONE DIMENSIONAL MODEL IS USED TO EVALUATE THE FLAME CHARACTERISTICS. THE FLAME STRUCTURE IS DIVIDED INTO THREE ZONES: PREHEAT ZONE, REACTION ZONE AND POST-FLAME ZONE. ALSO PREHEAT ZONE IS ALSO DIVIDED INTO FOUR SUBZONES ITSELF: FIRST HEATING SUBZONE AND DRYING SUBZONE, SECOND HEATING SUBZONE AND VOLATILE EVAPORATION SUBZONE. FINALLY, EFFECT OF MOISTURE AND ALSO EFFECTS OF SOME IMPORTANT PARAMETERS, LIKE DEVOLATIZATION TEMPERATURE, , AND LEWIS NUMBERS ARE INVESTIGATED. INCREASE IN MOISTURE CONTENT CAUSES A REDUCTION IN BURNING VELOCITY DUE TO MOISTURE EVAPORATION RESISTANCE.

THE BIOMASS OF MUCOR INDICUS WAS USED FOR REMOVAL OF LEAD IONS FROM AQUEOUS SOLUTION. THE BIOMASS WAS USED AS BOTH UNTREATED AND TREATED FORM. BOTH TYPES WERE SUCCESSFUL IN REMOVAL OF LEAD IONS. THE TREATMENT WAS PERFORMED USING 0.5 M SODIUM HYDROXIDE ADDED TO THE FUNGI IN AN AUTOCLAVE. THE BIOMASS WAS DRIED BEFORE BIOSORPTION EXPERIMENTS. THE EFFECT OF DRYING TEMPERATURE ON BIOSORPTION CAPACITY WAS INVESTIGATED BY DRYING THE UNTREATED BIOMASS AT DIFFERENT TEMPERATURES OF AMBIENT, 0OC, AND 50 ºC. THE BEST DRYING TEMPERATURE IN WHICH THE BIOSORPTION CAPACITY WAS THE HIGHEST WAS 50OC. THE EFFECT OF PH IN THE RANGE OF 3.0-5.0 WAS STUDIED. BIOSORPTION OF UNTREATED BIOMASS WAS INDEPENDENT OF PH WHILE FOR TREATED BIOMASS, THE ADSORPTION CAPACITY INCREASED BY INCREASING THE PH. AT LOW PH, BIOSORPTION CAPACITY OF UNTREATED BIOMASS IS HIGHER THAN THAT OF TREATED ONE WHILE AT HIGHER PH, THE BIOSORPTION CAPACITY OF TREATED BIOMASS IS HIGHER. THE KINETIC OF BIOSORPTION WAS ALSO INVESTIGATED. THE TIME TO REACH THE EQUILIBRIUM FOR UNTREATED BIOMASS IS LESS THAN THAT FOR TREATED ONE. IN ORDER TO DESCRIBE KINETIC DATA, PSEUDO-FIRST ORDER, PSEUDO-SECOND ORDER, INTRA-PARTICLE DIFFUSION, AND ELOVICH MODELS WERE USED. HO’S PSEUDO-SECOND ORDER MODEL WAS THE BEST ONE FOR FITTING THE KINETIC DATA.

IN THIS PAPER OUR LAST MODEL IS EXTENDED AND THERMAL RADIATION IS TAKEN TO ACCOUNT, WHICH IS A DOMINANT MECHANISM IN ORGANIC DUST COMBUSTION. ALSO EFFECTS OF DEVOLATIZATION TEMPERATURE AND PARTICLE RADIUS ARE INVESTIGATED IN THIS PAPER. ONE DIMENSIONAL MODEL IS USED TO EVALUATE THE FLAME CHARACTERISTICS. THE FLAME STRUCTURE IS DIVIDED INTO THREE ZONES: PREHEAT ZONE, REACTION ZONE AND POST-FLAME ZONE. ALSO PREHEAT ZONE IS ALSO DIVIDED INTO FOUR SUBZONES ITSELF: FIRST HEATING SUBZONE AND DRYING SUBZONE, SECOND HEATING SUBZONE AND VOLATILE EVAPORATION SUBZONE. THE OBTAINED RESULTS SHOW THAT THE INDUCED THERMAL RADIATION FROM FLAME INTERFACE INTO THE PREHEAT AND VAPORIZATION ZONES PLAYS A SIGNIFICANT ROLE IN THE IMPROVEMENT OF VAPORIZATION PROCESS AND BURNING VELOCITY OF ORGANIC DUST MIXTURE, COMPARED WITH THE CASE IN WHICH THE THERMAL RADIATION FACTOR IS NEGLECTED. ACCORDING TO RESULTS, BURNING VELOCITY AND MASS FRACTION OF GASEOUS FUEL STRONGLY DEPEND ON RADIATIVE HEAT TRANSFER. BY CONSIDERING RADIATION EFFECT OUR RESULTS HAVE BETTER AGREEMENT WITH EXPERIMENTAL DATA.