CHEMICAL ENGINEERING CONGRESS AND EXHIBITION | Year:2008 | دوره:5 |Papers Count:50

BOILING OF PURE COMPONENTS HAS BEEN WELL DISCUSSED IN THE LITERATURE, WHILE THE BOILING OF SOLUTIONS HAS BEEN STUDIED IN LESS DETAIL DUE TO ITS HIGH COMPLEXITY. IN THIS INVESTIGATION, A LARGE NUMBER OF EXPERIMENTS HAVE BEEN PERFORMED TO MEASURE THE NUCLEATE BOILING HEAT TRANSFER COEFFICIENTS OF WATER/DIETHANOLAMINE (DEA) AND WATER/MONOETHANOLAMINE (MEA) BINARY SOLUTIONS. BASED ON OUR EXPERIMENTAL DATA, EFFECTS OF DIFFERENT PHYSICAL PROPERTIES SUCH AS SURFACE TENSION, VISCOSITY AND DENSITY OF SOLUTIONS ON NUCLEATE BOILING HEAT TRANSFER COEFFICIENTS AND ALSO ON BUBBLE DYNAMICS HAVE BEEN DISCUSSED. FURTHERMORE, IN THIS ARTICLE A NEW CORRELATION HAS BEEN DEVELOPED ON THE BASIS OF CORRELATION OF STEPHAN AND KÖRNER WHICH IS KNOWN AS A SUCCESSFUL CORRELATION FOR THE PREDICTION OF NUCLEATE BOILING HEAT TRANSFER COEFFICIENT OF SOLUTIONS. COMPARISON OF THE PREDICTION OF NEW CORRELATION WITH OUR EXPERIMENTAL DATA INDICATES THAT THIS MODIFICATION CAN SIGNIFICANTLY IMPROVE THE PERFORMANCE OF STEPHAN AND KÖRNER CORRELATION.

IN THIS ARTICLE, DISTRIBUTIONS OF LOCAL SHEAR RATES FOR RUSHTON TURBINE IMPELLER HAVE BEEN STUDIED USING LASER DOPPLER ANEMOMETRY (LDA) FOR VISCOELASTIC LIQUIDS. THE NORMALIZED LOCAL TANGENTIAL VELOCITY AND LOCAL SHEAR RATE PROFILES ARE INDEPENDENT OF RUSHTON TURBINE IMPELLER SPEEDS AND MAIN VARIATIONS OF SHEAR RATE OCCUR IN THE VICINITY OF IMPELLER. THIS IS DUE TO THE LARGE VARIATIONS IN TANGENTIAL VELOCITY IN THIS REGION. IN THE TRANSITION REGION, I. E. ~30 < RE < ~2000, TANGENTIAL VELOCITY COMPONENT AND LOCAL SHEAR RATE, ARE SHOWN TO BE NEGLIGIBLE AT AXIAL COORDINATE OF Z = 0.0315 M ABOVE IMPELLER TIP PLANE, I. E. Z =0.

SLURRY BUBBLE COLUMN ARE USED FOR A WIDE RANGE OF CATALYTIC REACTIONS IN CHEMICAL INDUSTRY FOR NATURAL GAS CONVERSION TO USEFUL FUELS WITH FISCHER TROPSCH SYNTHESIS. IN SLURRY BUBBLE-COLUMN REACTORS ARE TWO PRINCIPAL FLOW REGIME: HOMOGENEOUS AND HETEROGENEOUS. GAS LIQUID MIXTURE HAVE DIFFERENT BEHAVIOR IN THE HOMOGENEOUS AND HETEROGENEOUS REGIME, SINCE THE RATE OF HEAT AND MASS TRANSFER DEPENDS ON THE HYDRODYNAMIC CONDITIONS.THE RELATION BETWEEN SUPERFICIAL GAS VELOCITY, CONCENTRATION OF SOLID SUSPENSION, LIQUID HEIGHT AND GAS SPARGER TYPE WITH GAS HOLD-UP ARE IMPORTANT DESIGNING PARAMETERS TO PREDICT THE HYDRODYNAMIC BEHAVIOR OF SLURRY BUBBLE-COLUMN REACTORS.ACCORDING TO DIFFERENT REPORTED CORRELATIONS, DISTINGUISHING THE BEST CORRELATION IS THE MOST IMPORTANT FACTOR FOR SCALING UP THE SLURRY BUBBLE-COLUMN REACTORS. OUR EXPERIMENTAL REACTOR IS A CYLINDRICAL BUBBLE-COLUMN MADE OF GLASS. WITH AN INSIDE DIAMETER OF 0.15(M) AND A HEIGHT OF 2.8(M). THE COLUMN ARE EQUIPPED TWO SPARGER, A POROUS PLAT AND A PERFORATED WITH THE SAME POROSITY GAS HOLD UP CAN BE DETERMINE WITH DIFFERENTIAL PRESSURE THEN TO ESTIMATE THE TRANSITION VELOCITY IN SLURRY BUBBLE COLUMN REACTORS. TO STUDY THE INFLUENCE OF PARTICLE CONCENTRATION ON THE HYDRODYNAMICS OF SLURRY BUBBLE COLUMN REACTORS, THE RESULTS SHOW THAT INCREASING THE SOLID CONCENTRATION (SILICA POWDER) DECREASE THE TOTAL GAS HOLD UP. ALSO THE DIAMETER OF BUBBLES ARE CHANGED WITH SPARGER TYPE AT CONSTANT POROSITY AND TO MAKE IMPORTANT EFFECT ON GAS HOLD UP.THE OTHER IMPORTANT PARAMETER ON GAS HOLD UP IN SLURRY BUBBLE COLUMN IS HEIGHT. THAT INCREASING THE LIQUID HEIGHT IN CREASE THE RESIDENT TIME IN THE REACTOR THERE FOR INCREASE THE GAS HOLD UP BUT THE ARE SOME LIMITATIONS FOR INCREASING COLUMN HEIGHT AND DETERMINING THE BEST HEIGHT IS IMPORTANT FACTOR FOR SCALING UP AND PREDICTING HYDRODYNAMIC BEHAVIOR.

THE CONVECTION AND MICROWAVE-CONVECTION DRYING OF GARLIC CLOVES WERE CARRIED OUT IN A LABORATORY SCALE MICROWAVE DRYER, WHICH WAS DEVELOPED FOR THIS STUDY. ON BOTH TECHNIQUES THE SAMPLE SIZES WERE ABOUT 1.09 GR EACH, AND WITH THICKNESSES OF 5 AND 7 MM. EXPERIMENTS WERE CARRIED OUT AT TEMPERATURE OF 40O C, 100O C AND 140O C AT AIR VELOCITY OF 1.0 M/S IN MICROWAVE-CONVECTION METHOD USING POWERS OF 100, 180 AND 300 W. THE EFFECT OF AIR TEMPERATURE AND SAMPLE THICKNESS AND IN MICROWAVE-CONVECTION THE EFFECT OF POWER, ON DEHYDRATION CHARACTERISTICS OF GARLIC SLICES WAS EXAMINED. THE TRANSPORT OF WATER DURING DEHYDRATION WAS DESCRIBED BY FICK’S EQUATION AND THE EFFECTIVE DIFFUSIVITY WAS BETWEEN 2.9 AND 31´1010 M2/S IN MICROWAVE-CONVECTION METHOD AND, BETWEEN 0.7 AND 5.6 ×1010 M2/S IN CONVECTION METHOD. THE EFFECT OF TEMPERATURE ON THE EFFECTIVE DIFFUSIVITY WAS DESCRIBED BY THE ARRHENIUS-TYPE RELATIONSHIP. THE ACTIVATION ENERGY IN THE MICROWAVE-CONVECTIVE DRYING RANGED BETWEEN 2.54 AND 14.67 KJ/MOL AND IN CONVECTIVE DRYING WAS BETWEEN 16.38 AND 18.84 KJ/MOL. ON BOTH METHODS, THE EXPERIMENTAL DEHYDRATION DATA OF GARLIC SLICES WERE FITTED TO THE FIVE WELL-KNOWN SEMI-THEORETICAL DRYING MODELS, I.E. THE HENDERSON AND PABIS, TWO TERM, LEWIS, PAGE AND VERMA ET AL. MODELS. THE ACCURACIES OF THE MODELS WERE MEASURED USING THE COEFFICIENT OF DETERMINATION (R2), ROOT MEAN SQUARE ERROR (RMSE) AND SUM OF SQUARE ERROR (SSE). ALL FIVE MODELS ARE ACCEPTABLE FOR DESCRIBING DEHYDRATION CHARACTERISTICS OF GARLIC SLICES, HOWEVER BASED ON STATISTICAL ANALYSIS, THE PAGE, THE VERMA AND THE TWO-TERM MODEL SHOWED A BETTER PERFORMANCE TO PREDICT DEHYDRATION CHARACTERISTICS. IN THIS PAPER, AFTER EXAMINING ABOVE MENTIONED MODELS, A MATHEMATICAL MODEL WAS DEVELOPED AND SHOWED BETTER FITNESS TO THE EXPERIMENTAL DATA COMPARED TO THE OTHER MODELS.

BOILING HEAT TRANSFER IS USED MOST COMMONLY IN CHEMICAL AND PETROCHEMICAL INDUSTRIES EITHER TO GENERATE VAPOR OR BECAUSE OF ITS HIGH EFFICIENCY IN COOLING. THE HIGH EFFICIENCY OF BOILING IS CONTRIBUTED TO THREE MECHANISMS NAMELY THE NATURAL CONVECTION TO THE LIQUID, LATENT HEAT FLOW BY MICRO-LAYER EVAPORATION BETWEEN BUBBLES AND HEAT TRANSFER SURFACE, AND THE INTENSE MICRO-CONVECTION FLOW ADJACENT TO THE HEAT TRANSFER SURFACE WHICH INDUCED BY GROWTH AND DETACHMENT BUBBLES. ALL THESE MECHANISMS ARE STRONG FUNCTION OF BUBBLE GROWTH RATE AND ITS ACCURATE PREDICTION IS CRUCIAL FOR THE THEORETICAL PREDICTION OF BOILING HEAT TRANSFER COEFFICIENT. UNFORTUNATELY, THE PROPOSED CORRELATIONS ARE EITHER SIMPLE WITH A LIMITED RANGE OF VALIDITY OR COMPLICATED. IN THE PRESENT WORK A UNIFIED MODEL IS PRESENTED BY SOLVING EQUATION OF ENERGY WHICH IS EXPRESSED BYR=MÖT ERF (NÖT)+ROIN THIS ARTICLE, FIRST THE FUNDAMENTAL APPROACH OF DEVELOPING OF PRESENTED MODEL IS DISCUSSED. THEN THE PREDICTION OF THIS MODEL IS COMPARED WITH AVAILABLE EXPERIMENTAL DATA FOR METHANOL AND WITH THOSE OF BETTER PERFORMING CORRELATION FROM THE LITERATURE. THE ABSOLUTE AVERAGE ERROR BETWEEN THE PREDICATED AND THE EXPERIMENTAL DATA IS LESS THAN 20% FOR METHANOL, WHICH CONFIRMS THE APPLICABILITY OF THE SUGGESTED MODEL.R=MÖT ERF (NÖT)+RO

THIS PAPER PRESENTS A COMPUTATIONAL STUDY OF THE FLOW BEHAVIOR IN A COLD-FLOW SCALE CIRCULATING FLUIDIZED BED. A MULTI-FLUID COMPUTATIONAL FLUID DYNAMICS (CFD) MODEL HAS BEEN DEVELOPED AND VERIFIED AGAINST EXPERIMENTAL DATA REPORTED IN THE LITERATURE. THE FLOW MODEL IS BASED ON AN EULERIAN DESCRIPTION OF THE PHASE WHERE THE KINETIC THEORY OF GRANULAR FLOW FORMS THE BASIS FOR THE TURBULENCE MODELING IN THE SOLID PHASE. THE MODEL IS GENERALIZED FOR ONE GAS PHASE AND MEAN PARTICLE SIZE OF SOLIDS PHASE TO ENABLE A REALISTIC DESCRIPTION OF THE PARTICLE SIZE DISTRIBUTION IN GAS - SOLIDS FLOW SYSTEMS. SOLID PHASE IS CHARACTERIZED BY A MEAN DIAMETER, DENSITY AND RESTITUTION COEFFICIENT. MOST EMPHASIS IS GIVEN TO STUDY THE EFFECTS OF MEAN PARTICLE SIZE DISTRIBUTIONS TO STUDY THE FLUCTUATING BEHAVIOR OF THE DILUTE GAS-SOLIDS FLOW SYSTEM. ALTOGETHER, THE SIMULATION RESULTS ARE IN GOOD AGREEMENT WITH EXPERIMENTAL DATA. BOTH MEAN DIAMETERS, AXIAL AND RADIAL MEAN AND TURBULENT VELOCITIES ARE CALCULATED SUCCESSFULLY.

FLUID FLOW AND MASS TRANSFER IN A 90O BEND WAS INVESTIGATED NUMERICALLY. THE RNG VERSION OF K–E MODEL WAS USED FOR TURBULENCE PREDICTION. MAXIMUM MASS TRANSFER RATE WAS PREDICTED AT A DISTANCE ONE DIAMETER DOWNSTREAM OF THE ELBOW. NUMERICAL ANALYSIS RESULTS ARE IN GOOD AGREEMENT WITH EXPERIMENTAL RESULTS OBTAINED FROM LITERATURE.

AN APPROACH FOR REDUCTION OF TRIETHYLENE GLYCOL (TEG) LOSSES AND ENERGY CONSUMPTION IN DEHYDRATION FACILITY IS PRESENTED. DEHYDRATION OF NATURAL GAS IN AN INDUSTRIAL PACKED COLUMN ABSORBER HAS BEEN INVESTIGATED. CALCULATIONS OF MINIMUM TEG CONCENTRATIONS REQUIRED FOR GIVEN CONDITIONS AND DEW POINT TEMPERATURE REQUIRED WERE MADE. A RATE BASED MODEL HAS BEEN GIVEN FOR SIMULATION OF RANDOM AND STRUCTURED PACKING COLUMNS .THE MODEL EQUATIONS ARE INCLUDED MATERIAL AND ENERGY BALANCES OF DEHYDRATION UNIT. THE MODEL RESULTS SHOW THE STRUCTURED PACKED BED HAS HIGHER PERFORMANCE THAN RANDOM PACKED BED.

FOR TWO IMMISCIBLE FLUIDS IN STEADY STATE, STRATIFIED LAMINAR, FULLY DEVELOPED FLOW WHICH ONE OF THEM IS NEWTONIAN AND THE OTHER IS BINGHAM PLASTIC THE MOTION EQUATIONS IN HORIZONTAL PIPE WITH APPROPRIATE BOUNDARY CONDITION HAVE BEEN SOLVED ANALYTICALLY. VELOCITY DISTRIBUTION FOR TWO PHASES AND THE LOCATION OF PLUG REGION RELATED TO BINGHAM PLASTIC FLUID HAVE BEEN REPORTED. THE RESULTS SHOW THAT THE NON-NEWTONIAN RHEOLOGICAL PROPERTIES HAVE NEGLIGIBLE EFFECTS ON TWO PHASE VELOCITY PROFILE.

IN THE PRESENT STUDY, SOME EXPERIMENTS WERE PERFORMED ON THE ADSORPTION OF BENZENE, TOLUENE, ETHYLBENZENE AND XYLENE (BTEX) FROM AMINE SOLUTION BY GRANULAR ACTIVATED CARBON. ISOTHERM STUDIES WERE CONDUCTED TO EVALUATE THE ADSORPTION BEHAVIOR OF THE ACTIVATED CARBON. THE LANGMUIR, FREUNDLICH AND REDLICH-PETERSON ISOTHERM MODELS WERE USED TO DESCRIBE THE EQUILIBRIUM DATA. A MATHEMATICAL MODEL WAS PROPOSED FOR DESCRIBING THE BTEX TRANSFER BETWEEN THE AMINE SOLUTION AND SOLID PARTICLES. TO EVALUATE THE VALIDITY OF THE PROPOSED MODEL, A PILOT – PLANT WAS CONSTRUCTED, IN WHICH THE BREAKTHROUGH CURVE FOR DIFFERENT COMPONENT WERE INVESTIGATED PRACTICALLY. THE RESULTS PREDICTED BY THE PROPOSED MODEL WERE COMPARED WITH THE EXPERIMENTAL RESULTS AND A SATISFACTORY AGREEMENT WAS OBSERVED BETWEEN THEM. THE EFFECTS OF THE DIFFERENT OPERATING PARAMETERS ON THE RATE OF ADSORPTION WERE ALSO DISCUSSED. THE RESULTS OF FIXED BED COLUMN TESTS SHOWED THAT THE ACTIVATED CARBON WAS VERY EFFECTIVE IN REMOVING THE BTEX FROM AMINE SOLUTION.

POLY (ETHER-BLOCK-AMIDE) MEMBRANES WERE MADE VIA CASTING A SOLUTION ON A NON SOLVENT SURFACE. IN THIS RESEARCH, EFFECTS OF DIFFERENT PARAMETERS SUCH AS RATIO OF SOLVENT MIXTURE (N-BUTANOL / ISO PROPANOL), TEMPERATURE AND POLYMER CONCENTRATION, ON QUALITY OF THE THIN FILM MEMBRANES WERE STUDIED. THE RESULTS SHOWED THAT THE FILM QUALITY ENHANCES WITH INCREASING ISO PROPANOL RATIO IN THE SOLVENT MIXTURE. THIS BEHAVIOR CAN BE RELATED TO REDUCTION OF SOLUTION SURFACE TENSION AND INTERFACIAL TENSION BETWEEN SOLUTION AND NON SOLVENT. UNIFORM FILMS WERE MADE AT A TEMPERATURE RANG OF 70-80OC AND A POLYMER CONCENTRATION OF 4-7 WT%. MORPHOLOGY OF THE MEMBRANE WAS INVESTIGATED WITH SCANNING ELECTRONIC MICROGRAPH (SEM). PERVAPORATION OF ETHYL BUTYRATE / WATER AND ISO PROPANOL / WATER MIXTURES WAS STUDIED USING THESE MEMBRANES AND HIGH SEPARATION PERFORMANCE WAS ACHIEVED. FOR ETHYL BUTYRATE / WATER MIXTURES, IT WAS OBSERVED THAT BOTH PERMEATION FLUX AND SEPARATION FACTOR INCREASE WITH INCREASING ETHYL BUTYRATE CONTENT IN THE FEED. HOWEVER, FOR ISO PROPANOL / WATER MIXTURES, IT WAS FOUND THAT BY INCREASING ISO PROPANOL CONTENT IN THE FEED, PERMEATION FLUX ENHANCES BUT SEPARATION FACTOR DIMINISHES. INCREASING TEMPERATURE IN LIMITED RANGE STUDIED RESULTED IN DECREASING SEPARATION FACTOR AND INCREASING PERMEATION FLUX.

THE KINETICS OF THE MAIN REACTION AND DEACTIVATION OF THE CATALYST IN DEHYDROGENATION OF HIGHER (C10-C14) NORMAL PARAFFINS OVER PT-BASED CATALYST WAS STUDIED. A SIMPLE MATHEMATICAL MODEL FOR CATALYST DECAY BASED ON A REVERSIBLE MAIN REACTION AND CONCENTRATION-INDEPENDENT, NTH-ORDER DECAY LAW WAS PRESENTED. THE MODEL WAS CHECKED BOTH THROUGH INTEGRAL ANALYSIS OF EXPERIMENTAL DATA AND NONLINEAR ESTIMATION FUNCTIONS OF TEMPERATURE-TIME DATA OF A COMMERCIAL PLANT, AND MODEL PARAMETERS WERE EVALUATED. THE RESULTS OF BOTH APPROACHES WERE CONSISTENT, THAT IS, THE DEACTIVATION RATE LAW WAS FOUND TO BE OF SECOND ORDER. THE ACTIVATION ENERGIES OF THE DEHYDROGENATION AND CATALYST DECAY WERE FOUND TO BE 90 KJ/MOL AND 140 KJ/MOL, RESPECTIVELY.

THE LIQUID MIXING TIME, CIRCULATION TIME, AND CIRCULATION VELOCITY IN THE RISER AND TWO DOWN COMERS OF A MODIFIED AIRLIFT LOOP REACTOR WITH DOUBLE DRAFT TUBES WERE INVESTIGATED. THE MIXING PARAMETERS FOUND WITH USING TRACER TECHNIQUE IN A COLUMN OF 18.5CM IN DIAMETER, 90CM IN HEIGHT, AND TWO CONCENTRIC DRAFT TUBES OF 14 AND 8.5CM IN DIAMETER AND 82CM IN HEIGHT RESPECTIVELY. THE TRACER INJECTION METHOD AND IMPULSE RESPONSE WAS USED TO FIND THE MIXING PARAMETERS. THE MIXING TIMES DECREASED WITH SUPERFICIAL GAS VELOCITY, WITH A POWER CORRELATION. THE EXPONENT VALUES WERE -0.194, -0.197 AND -0.164 FOR RISER, INNER AND OUTER DOWN COMERS RESPECTIVELY, WHICH SHOWS THE LOWER VALUES OF MIXING TIME FOR DOUBLE DRAFT-TUBE CONFIGURATION COMPARED TO CONVENTIONAL ALR. THE MIXING PARAMETERS AND CIRCULATION VELOCITY ARE COMPARED FOR DIFFERENT PART OF THE COLUMN. FOR ALL INJECTIONS POINTS, THE SIMILAR RESULTS WERE ACHIEVED IN ALL SECTIONS. AN ASCENDING TREND OF CIRCULATION VELOCITY WITH THE INCREASE OF SUPERFICIAL GAS VELOCITY WAS SEEN. THE CIRCULATION VELOCITY IN RISER, INNER AND OUTER DOWN COMERS VARIED WITH AN EXPONENT OF 0.235, 0.145, AND 0.177 WITH SUPERFICIAL GAS VELOCITY RESPECTIVELY. THE LIQUID CIRCULATION VELOCITY IN THE OUTER DOWNCOMER SHOWED HIGHER VALUES, BECAUSE OF HIGHER WALL EFFECTS AND LOSSES, THAN THE INNER ONE.

IN THE PRESENT INVESTIGATION, NUMERICAL SIMULATIONS WERE PERFORMED TO STUDY FLOW THROUGH CONVERGING TWO-DIMENSIONAL PLATES. THE FLOW WAS CONSIDERED TO BE LAMINAR, STEADY AND INCOMPRESSIBLE. THE INFLUENCES OF REYNOLDS NUMBER AND CONVERGING ANGLE OF PLATES ON THE PRESSURE DROP, FRICTION FACTOR, CENTERLINE VELOCITY AND VELOCITY PROFILE IN DEVELOPING AND FULLY DEVELOPED REGIONS WERE STUDIED. THE SET OF GOVERNING DIMENSIONLESS EQUATIONS WITH APPROPRIATE BOUNDARY CONDITIONS WERE SOLVED TOGETHER USING NUMERICAL FINITE VOLUME METHOD. RESULTS INDICATE THAT AS THE PLATES CONVERGING ANGLE INCREASES THE DIMENSIONLESS PRESSURE DROP, FRICTION FACTOR AND CENTERLINE VELOCITY INCREASE. ALSO INCREASING THE REYNOLDS NUMBER INCREASES THE WALL VELOCITY GRADIENT AND ENTRANCE HYDRODYNAMIC LENGTH.

TURBULENT FLOW IN A BAFFLED MIXING TANK STIRRED BY AN IMPELLER WAS SIMULATED USING CFD. THE EFFECT OF BAFFLE ANGLES WITH RESPECT TO THE VERTICAL DIRECTION AND POSITION OF BAFFLE WITH RESPECT TO THE TANK WALL ON FLOW AND TURBULENT PROPERTIES HAS BEEN STUDIED. MULTIPLE REFERENCE FRAME (MRF) TECHNIQUE WAS USED FOR CALCULATIONS. IN THIS METHOD FLOW FIELD IS DIVIDED INTO TWO PARTS, THE INNER PART CO-ROTATING WITH THE IMPELLER AND OUTER PART WHICH IS FIXED. IT WAS FOUND THAT BAFFLE EDGE HAS CONSIDERABLE EFFECT ON SOME FLOW PARAMETERS SUCH AS VELOCITY MAGNITUDE, TURBULENT ENERGY DISSIPATION RATE AND TURBULENT KINETIC ENERGY.

A 2D LATTICE BOLTZMANN BGK (LBGK) MODEL ON A D2Q9 LATTICE WAS CONSTRUCTED AND TESTED FOR ACCURACY IN AN EXAMPLE PHYSICAL SITUATION. AN INTRODUCTION TO THE LBGK METHOD IS GIVEN FOLLOWED BY A BRIEF OUTLINE OF THE COMPUTER MODEL CONSTRUCTION IN MATLAB ENVIRONMENT. EFFECTS OF VISCOSITY AND LATTICE NUMBER VARIATION ON VELOCITY RESULTS WERE ALSO EXAMINED. THE LBM SIMULATION RESULTS ILLUSTRATE A GOOD AGREEMENT WITH ANALYTICAL SOLUTION OF PRESSURE DRIVEN FLOW THROUGH 2D SYMMETRIC CHANNEL.

IN THIS ARTICLE, IT WAS STUDIED HOW TO ACHIEVE TO A SHELL-AND-TUBE HEAT EXCHANGER WITH AN OPTIMUM HELICAL BAFFLE OF 42 DEGREES USING CFD ANALYSIS. THE STUDY WAS FOLLOWED BY CONSIDERING SHELL SIDE FLOW PATTERN MOVEMENT AND THERMAL ANALYSIS OF THE EXCHANGER. FINALLY, A COMPARISON WAS MADE BETWEEN A HEAT EXCHANGER WITH SEGMENTAL BAFFLE AND OPTIMAL GEOMETRY OF 25% BAFFLE CUT AND A HELICAL EXCHANGER. IN ADDITION, A MODIFIED EQUATION FOR TURBULENT FLOW IN SHELL SIDE OF HELICALLY BAFFLED EXCHANGER WAS DEVELOPED. THIS STUDY EMPHASIZED THAT THE HELICALLY BAFFLED EXCHANGERS CAN BE REMOVED AND BE MINIMIZED THE MAIN LIMITATIONS OF DESIGN FOR THE COMMON EXCHANGERS WITH SEGMENTAL BAFFLE. IT WAS RECOGNIZED THAT HELIX EXCHANGERS HAVE A HIGHER THERMAL PERFORMANCE AND A LOWER FOULING TENDENCY.

IN THIS STUDY A MATHEMATICAL MODEL IS DEVELOPED IN ORDER TO SIMULATE FLUORINATION REACTION OF URANIUM DIOXIDE LEADING TO PRODUCE URANIUM HEXAFLUORIDE. THE MODEL CONSIDERS HOMOGENEOUS REACTION FOR INTERMEDIATE SOLID AND HETEROGENEOUS ONE FOR UNREACTED SHRINKING CORE. ALSO THIS STUDY TRIES TO CLEARLY SHOW THE SHORTCOMING OF THOSE FOREGOING MODELS THAT TAKE SURFACE REACTIONS FOR BOTH SOLIDS. IN FACT, ONE MAY NOT TRUST THE ACCURACY OF THOSE MODELS DUE TO IGNORE IMPORTANCE OF THE DIFFUSION PHENOMENA INTO THE INTERMEDIATE SOLID AND TAKING PLACE THE REACTION WITHIN IT. ON THE OTHER HAND, NEGLECTING THE UNDENIABLE EFFECTS OF OPERATING CONDITIONS INCLUDING TEMPERATURE AND PARTICLE SIZES ON GAS CONCENTRATION DISTRIBUTION AND REACTION RATES MAY INTRODUCE LARGE DEVIATIONS. FOR THIS MENTIONED PURPOSES THE GOVERNING EQUATIONS ARE DERIVED ON THE BASIS OF THE MASS CONSERVATION LAW AND SOLVED NUMERICALLY. BESIDES, THE FIRST TIME, SOME DIMENSIONLESS EQUATIONS AND GROUPS ARE INTRODUCED TO PREDICT REACTION RATES AND AMOUNT OF THE MAIN AND THE INTERMEDIATE PRODUCTS FOR USING IN NUMERICAL PROCEDURE. COMPARING THE MODEL RESULTS WITH CORRESPONDING EXPERIMENTAL ONES REPRESENTS THE DESIRABLE ACCURACY OF THE MODEL. AFTER VALIDATION OF THE MODEL, THE EFFECT OF SOME OPERATIONAL VARIABLES SUCH AS TEMPERATURE AND INITIAL PARTICLE SIZE ARE INVESTIGATED ON THE REACTION RATES AND CONVERSIONS.

A SERIOUS ENVIRONMENTAL THREAT FROM HEAVY METAL ION POLLUTION, ESPECIALLY MERCURY, HAS GENERATED A GREAT DEAL OF ATTENTION IN RECENT YEARS. IN THIS PAPER, WE HAVE EVALUATED THE EFFORTS WHICH HAVE BEEN DONE FOR CONTROLLING THE MERCURY EMISSIONS FROM AQUEOUS SOLUTIONS. ACCORDING TO THE INDIAN STANDARD INSTITUTION, THE TOLERANCE LIMIT FOR HG (II) FOR DISCHARGE INTO INLAND SURFACE WATER IS 10MG/L AND FOR DRINKING WATER IS 1MG/L. MERCURY (HG) IS ONE OF THE HEAVY METALS OF CONCERN AND HAS BEEN FOUND IN THE WASTE WATERS COMING FROM MANUFACTURING INDUSTRY, OIL REFINERY, MATERIALS PROCESSING AND NATURAL SOURCES. AMONG SEVERAL TYPES OF TECHNOLOGY FOR REMOVING OF HG IN WATER (CHEMICAL PRECIPITATION, REVERSE OSMOSIS, ION-EXCHANGE, ETC.), ADSORPTION IS ONE OF MOST FREQUENTLY USED. IT IS A COMPLEX PROCESS INVOLVING PHYSICAL, CHEMICAL, AND ELECTRICAL INTERACTIONS AT SORBENT SURFACES.

DRYING BEHAVIOR OF GREEN PEAS IS INVESTIGATED IN A PILOT SCALED FLUIDIZED BED DRYER WITH INERT PARTICLES ASSISTED BY AN INFRARED HEATING SOURCE. THE VARIATIONS OF SHRINKAGE AND MOISTURE DIFFUSIVITY WITH TEMPERATURE AND MOISTURE CONTENT WERE INVESTIGATED. THE VARIATIONS OF SHRINKAGE ARE A FUNCTION OF MOISTURE CONTENT. IT WAS FOUND THAT SHRINKAGE WAS A FUNCTION OF MOISTURE CONTENT AND MOISTURE DIFFUSIVITY WAS ALSO DEPENDENT ON TEMPERATURE. THE VALUES OF MOISTURE DIFFUSIVITY WHICH OBTAINED ARE IN THE RANGE OF 5E-10 TO 30E-10. SOME CORRELATIONS WERE PROPOSED FOR THESE PROPERTIES.

FALLING FILM IS IMPORTANT IN MANY INDUSTRIES, BUT ITS IMPORTANCE IS BECAUSE OF ITS CLASSICAL CONCEPTS. MODELING AND SOLVING THE FALLING FILM WERE ALWAYS PERFORMED WITH SIMPLIFYING ASSUMPTIONS. IN THIS RESEARCH FALLING FILM MODELING AND SIMULATION PERFORMED WITH LEAST SIMPLIFICATIONS. MASS TRANSFER AND NAVIER-STOKES EQUATIONS COUPLED TOGETHER TO OBTAIN REAL RESULTS.

MIXING PROCESS IS ONE OF THE MOST IMPORTANT PHENOMENA IN ENGINEERING SCIENCE. TURBULENT EFFECT AND OSCILLATIONS IN THE BASE FLOW INCREASE THE MIXING RATE NOTICEABLY. IN THIS RESEARCH A NON-REACTING CONCENTRATION FIELD IN A MIXING LAYER IS SIMULATED FOR HIGH REYNOLDS NUMBER BY SOLVING THE SCALAR TRANSPORT EQUATIONS. WE USED A GRID FREE CFD SCHEME NAMED TRANSPORT ELEMENT METHOD IN ORDER TO MODEL THE CONCENTRATION FIELD IN A LAGRANGIAN FRAME. THE CONCENTRATION GRADIENT IS CALCULATED IN VORTEX STRUCTURES AND OTHER CROSS SECTIONS IN THE FIELD. ALSO MEAN CONCENTRATION PROFILE AND CONCENTRATION FLUCTUATION DIAGRAM ARE OBTAINED FOR VARIOUS DIFFUSION COEFFICIENTS. THE RESULTS ARE IN GOOD AGREEMENT WITH OTHER EXPERIMENTAL DATA.

WASTE HEAT RECOVERY IS VERY IMPORTANT, BECAUSE NOT ONLY IT REDUCES THE EXPENDITURE OF HEAT GENERATION, BUT ALSO IT IS OF HIGH PRIORITY IN ENVIRONMENTAL CONSIDERATION, SUCH AS REDUCTION IN GREENHOUSE GASES. ONE OF THE DEVICES IS USED IN WASTE HEAT RECOVERY IS HEAT PIPE HEAT EXCHANGER. AN EXPERIMENTAL AND THEORETICAL RESEARCH HAS BEEN CARRIED OUT TO INVESTIGATE HEAT PERFORMANCE OF AN AIR TO WATER THERMO SYPHON HEAT PIPE HEAT EXCHANGER ACCORDING TO E-NTU METHOD. THE EXPERIMENTS WERE DONE ACCORDING TO THE FOLLOWING PROCEDURE: COLD WATER WITH 0.1KG/S FLOWS THROUGH THE CONDENSATION SECTION AND HOT AIR IN A CLOSED CYCLE IS BLOWN TO THE EVAPORATION SECTION. A BLOWER WITH VARYING FREQUENCY OF CURRENT TURNS IN THE MASS FLOW RATE BETWEEN 0.14-0.6 KG/S AND TEMPERATURE RANGE OF 125-225OC.THE RESULTS OF EXPERIMENTS SHOW THAT AS THE RATIO OF CH/CC RISES THE AMOUNT OF HEAT BEING TRANSFERRED GOES UP. THE EFFICIENCY OF HEAT PIPE HEAT EXCHANGER REMAINS CONSTANT AS THE TEMPERATURE OF HOT STREAM GOES UP BUT THE AMOUNT OF HEAT TRANSFERRED INCREASES.

HYDRODYNAMIC AND THERMAL PERFORMANCE OF A HEAT PIPE HEAT EXCHANGER DEPENDS ON A NUMBER OF PARAMETERS SUCH AS HEAT PIPE DIAMETER, BUNDLE GEOMETRY, ORIENTATION, FIN SPACING AND SIZE, ETC. IN THIS PAPER EXPERIMENTAL AND THEORETICAL RESEARCH HAS BEEN CARRIED OUT TO INVESTIGATE THE PRESSURE DROP ACROSS TUBE BUNDLE OF AN AIR TO LIQUID THERMO SYPHON HEAT PIPE HEAT EXCHANGER (THPHE). ACCORDING TO EXPERIMENTAL DATA AND THE OTHER METHODS, A NEW CORRELATION FOR THPHE WITH INDIVIDUAL FINNED TUBES AND IN-LINE GEOMETRY HAS BEEN INTRODUCED. THE ERROR OF PRESSURE DROP FOR 40 EXPERIMENTAL POINTS IN THE NEW CORRELATION IS LESS THAN %15. IT INDICATES THAT THE NEW CORRELATION POSSESSES AN ACCEPTABLE ACCURACY IN THE PREDICTION OF PRESSURE DROP.

RECENT EXPERIMENTAL STUDIES SUGGEST THAT HOLLOW FIBER MEMBRANE BIOREACTORS (HFMBS) MAY BE USED TO GROW TISSUES IN THE LABORATORY, WHICH MAY THEN BE IMPLANTED INTO PATIENTS TO REPAIR SKELETAL DEFECTS. IT HAS BECOME NECESSARY TO DEVELOP A THEORETICAL FRAMEWORK THAT ELUCIDATES THE QUANTITATIVE RELATIONSHIPS BETWEEN THE CELL ENVIRONMENT AND TISSUE BEHAVIOR IN HFMBS IN ORDER TO GUIDE THE DESIGN OF EFFECTIVE BONE TISSUE ENGINEERING PROTOCOLS. AT THE SCALE OF THE LABORATORY DEVICE, THE TRANSPORT BEHAVIOR IS GOVERNED BY NON-LINEAR COUPLED CONVECTION-DIFFUSION AND REACTION PROCESSES. THIS PAPER PRESENTS AN APPROACH FOR SIMULATING GLUCOSE AND OXYGEN TRANSPORT IN HFMB FOR GROWING BONE TISSUES WHERE WE USE DIRECT NUMERICAL SIMULATION (FINITE ELEMENT METHOD) INSTEAD OF MORE TEDIOUS APPLIED MATHEMATICS THEOREMS FOR MODELING GLUCOSE AND OXYGEN TRANSPORT IN HFMB. THE NUMERICAL SOLUTIONS OF THE GOVERNING MODEL EQUATIONS HAVE BEEN OBTAINED USING THE SOFTWARE PACKAGE COMSOL. THE ADVANTAGE OF THIS APPROACH IS THAT IT DOES NOT RELY ON THE DETERMINATION OF AVERAGED TRANSPORT PROPERTIES (E.G., DIFFUSION COEFFICIENT) THAT APPEAR IN AVERAGED TRANSPORT EQUATIONS WHICH ARE OFTEN DIFFICULT TO MEASURE EXPERIMENTALLY OR MAY NOT HAVE SIGNIFICANT PHYSICAL MEANING. THE DEVELOPED FRAMEWORK IS THEN EMPLOYED TO CARRY OUT A SYSTEMATIC ANALYSIS OF THE INFLUENCE OF VARIOUS PROCESS PARAMETERS OF HFMB (E.G., FLUID VELOCITY, CELL DENSITY, ETC.) ON THE GLUCOSE AND OXYGEN TRANSPORT BEHAVIOR. IT IS ENVISAGED THAT THE DEVELOPED MULTISCALE TOOL WILL PROVIDE BETTER UNDERSTANDING OF THE FUNCTIONING OF HFMB FOR THE PURPOSES DISCUSSED ABOVE.

THE FLOW FIELD, POWER CONSUMPTION AND MIXING TIME IN A STANDARD BAFFLED STIRRED TANK WITH 6-BLADE RUSHTON TURBINE OVER A RANGE OF REYNOLDS NUMBERS WAS SIMULATED USING COMPUTATIONAL FLUID DYNAMICS (CFD). THE FLOW FIELD CALCULATIONS WERE PERFORMED USING A TIME DEPENDENT SLIDING MESH (SM) TECHNIQUE. MIXING TIME WAS SIMULATED BY INJECTING A TRACER FROM TOP OF THE TANK AND RECORDING CONCENTRATION OF SPECIES AT A SPECIFIC LOCATION IN PROBE INSTALLATION POINT. THE LARGE EDDY SIMULATION (LES) AS A TURBULENT MODEL WAS USED, AND THE EFFECT OF GRID DENSITY WAS EXAMINED BY REPEATING CALCULATION WITH HIGHER MESH DENSITY. POWER NUMBER AND VELOCITY PROFILE BETWEEN THESE TWO GRIDS WERE COMPARED WITH REPORTED RESULTS. RESULTS OF POWER NUMBER AND FLOW FIELD SHOW VERY GOOD AGREEMENT. THERE ARE IN FAIRLY REASONABLE AGREEMENTS WITH THE REPORTED VALUES OF PREDICTED MIXING TIME IN THE LITERATURE AT THE SIMILAR CONDITIONS.

IN THIS PAPER AN EXPERIMENTAL INVESTIGATION ON ELECTRO HYDRO DYNAMIC (EHD) AUGMENTATION OF HEAT TRANSFER FOR IN-TUBE CONDENSATION OF FLOWING REFRIGERANT R-134A IN PRESENCE OF NON-CONDENSABLE GAS (NC) IS PRESENTED. THE TEST SECTION IS A 1 M LONG COUNTER FLOW HEAT EXCHANGER. THE REFRIGERANT FLOWS IN THE INNER TUBE AND A ROD ELECTRODE PLACED IN THE TUBE CENTER. COOLING WATER FLOWS THROUGH THE HEAT EXCHANGER ANNULUS. THE EFFECTS OF ELECTRODE RODE DIAMETER, PRESENCE OF NON-CONDENSABLE GAS CONCENTRATION, AND APPLICATION OF VOLTAGE ON CONDENSATION ARE EXAMINED. RESULTS SHOW A REDUCTION IN HEAT TRANSFER BY FACTOR 2.1 UPON PRESENCE OF 20% OF NON-CONDENSABLE GAS. IN THE PRESENCE OF THE 20% OF NC AND 12MM ELECTRODE, A MAXIMUM HEAT TRANSFER ENHANCEMENT OF 1.9 IS EXPERIENCED BY APPLYING VOLTAGE OF 8 KV.

IN THE PRESENT RESEARCH, THE EFFECT OF THE HEAT FLUX AND THE COOLING WATER FLOW RATE OF THE CONDENSER ON OVERALL PERFORMANCE OF PARTIALLY VACUUMED THERMOSYPHON WERE STUDIED. A RIG WAS MADE FROM A 1 M COPPER TUBE WITH AN INSIDE AND AN OUTSIDE DIAMETER OF 17.5 AND 19 MM. THE HEIGHTS OF THE EVAPORATOR, THE ADIABATIC SECTION AND THE CONDENSER ARE 40, 20 AND 40 CM RESPECTIVELY. THE TEMPERATURES AT DIFFERENT PLACES ON THE THERMOSYPHON AND ON THE INLET/OUTLET OF THE COOLING WATER WERE MEASURED. IT WAS OBSERVED THAT WITH INCREASING OF HEAT FLUX TO THE EVAPORATOR THE THERMOSYPHON PERFORMANCE INCREASED. ON THE OTHER HAND, WITH DECREASING OF THE COOLING WATER FLOW RATE, THE PERFORMANCE OF THE THERMOSYPHON WAS INCREASED AS THE TRAPPED AIR MOVED TOWARD THE END OF THE CONDENSER. IN ORDER TO ILLUSTRATE THE EFFECT OF EXISTENCE OF AIR TO DEACTIVATING THE THERMOSYPHON, THE PIPE WAS COOL DOWN BY DISCONNECTING OF POWER INPUT TO THE EVAPORATOR. IT WAS SEEN THAT THE THERMOSYPHON LOSS ITS PERFORMANCE AS THE TRAPPED GAS OCCUPIES THE WHOLE CONDENSER. THE WHOLE STUDY SHOWS DUE TO EXISTENCE OF AIR, THE HEAT LOADS CAN HAVE SIGNIFICANT EFFECTS ON THE PERFORMANCE OF THE THERMOSYPHON.

IN PRESENT WORK THE DYNAMICS OF A FALLING FILM OF CMC SOLUTION AS A NON-NEWTONIAN FLUID OVER AN INCLINED SURFACE HAS BEEN STUDIED EXPERIMENTALLY. WITH ROTATIONAL RHEOMETER NAMED POLYVISC SERIES L, THE RHEOMETRY ANALYSIS OF THREE DIFFERENT CONCENTRATION OF CMC SOLUTION (1.1, 1.5 AND 2 WEIGHT PERCENT) WHICH IS EXTENSIVELY UTILIZED IN INDUSTRY HAVE BEEN REPORTED. FLUID-AIR SURFACE TENSION IS ALSO MEASURED BY THE CAPILLARY METHOD AND DYNAMICS OF THE FALLING FILM WERE STUDIED WITH HIGH SPEED IMAGING METHOD. FOR DIFFERENT FLOW RATE OF FLUID AND DIFFERENT INCLINATION ANGLES OF INCLINED PLATE A (0 < A < P / 2) TIME VARIATION OF FALLING FILM VELOCITY HAVE BEEN RECORDED AND AN EMPIRICAL CORRELATION HAS BEEN DERIVED. THE RESULTS SHOW THE EFFECTS OF RHEOLOGICAL PROPERTIES, PLATE INCLINATION AND FLOW RATE ON DYNAMICS OF FILM FLOW OF CMC SOLUTION.

IN THIS PAPER THE TRAJECTORY OF THIN SOLID PARTICLES IN AIR FLOW WHILE PASSING A LAB CHANNEL WITH A RECTANGULAR CROSS-SECTION, HAVE BEEN SIMULATED. HERE WE HAVE USED THE EULERIAN-LAGRANJIAN METHOD FOR MODELING THE TWO-PHASE FLOW, AND THE NUMERICAL SOLUTIONS TO GOVERNING EQUATIONS HAVE BEEN MADE THROUGH A FINITE VOLUME METHOD. IN LAGRANJIAN CALCULATIONS WHICH ARE BASED ON PARTICLE DYNAMICS, THE EFFECTS OF ANY FORCES SUCH AS LIFTING, DRAG, AND ET CETERA HAVE BEEN INCLUDED. AN SECOND POWER UPWIND DISCRETING APPROACH HAS BEEN USED FOR THE NUMERICAL SOLUTION OF MOMENTUM EQUATIONS, KINETIC ENERGY, DISSIPATION RATE AND TURBULENCE MODELS; ALSO THE COUPLED CALCULATIONS OF PRESSURE-VELOCITY HAVE BEEN DONE THROUGH SIMPLEC ALGORITHM. COMPARISON OF THE RESULTS OBTAINED FROM LAB DATA, INDICATE THAT THE CHOOSE OF PARAMETERS AND TURBULENCE MODEL (REYNOLDS STRESS) IS MORE SUITABLE FOR DILUTE PARTICLE-FLUID FLOW MODELING INSIDE CLOSED CHANNELS.

WATER MANAGEMENT IS CRITICALLY IMPORTANT FOR POLYMER ELECTROLYTE MEMBRANE (PEM) FUEL CELLS, AND IS COMPLICATED BY ELECTRO OSMOTIC FLOW OF WATER FROM ANODE TO CATHODE THROUGH THE POLYMER ELECTROLYTE MEMBRANE. IN THIS WORK, THE CHARACTERISTICS OF ELECTRO OSMOTIC FLOW IN A NAFION Ò MEMBRANE WITH NON-UNIFORM ZETA POTENTIAL WERE INVESTIGATED. THE POISSON-BOLTZMANN AND NAVIER-STOKES EQUATIONS WERE USED TO MODEL ELECTRICAL DOUBLE LAYER AND THE FLOW FIELDS, RESPECTIVELY. THE NUMERICAL RESULTS SHOW THE DISTORTED ELECTRO OSMOTIC VELOCITY PROFILES RESULTING FROM THE AXIAL VARIATION OF THE ZETA POTENTIAL.

PRESSURE DROP MEASUREMENTS FOR HORIZONTAL STRATIFIED TWO-PHASE FLOW OF AIR WATER HAVE BEEN PERFORMED IN A CHANNEL WITH 5.33M LENGTH, 0.20M WIDTH, AND 0.1M HEIGHT. THE GAS AND LIQUID REYNOLDS NUMBERS WERE VARIED IN THE 54000-87000 AND 13000-23000 RANGES, RESPECTIVELY. A CORRELATION WAS PROPOSED FOR PREDICTING PRESSURE DROP IN HORIZONTAL STRATIFIED TWO PHASE FLOW. PREDICTIONS OF THE CORRELATION PROPOSED IN THIS WORK WERE COMPARED WITH EXPERIMENTAL DATA AND SHOWED MUCH BETTER AGREEMENT COMPARED TO FRIEDEL EQUATION.

THE MIXING FIELD IN AN AERATED STIRRED REACTOR WITH TWO RUSHTON TURBINES WAS EXPERIMENTALLY ANALYSED USING THE PARTICLE IMAGE VELOCIMETRY AND DOUBLE-PLANER LASERINDUCED FLUORESCENCE MEASUREMENT TECHNIQUES. THE MIXING CHARACTERISTICS WERE MEASURED AT THREE DIFFERENT IMPELLER ROTATIONAL SPEEDS: 225, 300 AND 400 RPM, FOR BOTH SINGLE- AND BUBBLY TWO-PHASE MIXING SYSTEMS. THE MIXING TIME WAS DETERMINED FROM THE RESPONSE CURVES TO A PULSE INJECTION OF A RHODAMINE-590 TRACER INTO THE STIRRED TANK. A CONSIDERABLE REDUCTION IN MIXING TIME WAS ACHIEVED BY INCREASING THE IMPELLER SPEED AND IMPLEMENTING AERATION.

LIQUID PHASE RTD CURVES WERE INVESTIGATED IN CLASSICAL FIXED AND FLUIDIZED BED REGIMES WITH HIGH DENSITY PARTICLES. USING AN IMPULSE TRACER TECHNIQUE IN A COLUMN OF 5CM IN DIAMETER AND HEIGHT OF 1.2M, LIQUID'S RTD, MEAN RESIDENCE TIME (MRT) AND AXIAL DISPERSION COEFFICIENT (ADC) WERE DETERMINED. THE EFFECT OF LIQUID VELOCITY AND SOLID'S DENSITY WERE STUDIED ON HYDRODYNAMICS OF BED. ADC VARIED FROM 1.62 TO 8.23 FOR THE PARTICLE REYNOLDS NUMBER OF 43.18 TO 279.41. ADC INCREASES WITH INCREASING LIQUID SUPERFICIAL VELOCITY. AS DIFFERENCE BETWEEN SOLID AND LIQUID DENSITY INCREASES, ADC DECREASES IN AN IDENTICAL REYNOLDS NUMBER.

IN THE EXPERIMENTAL INVESTIGATION CARRIED OUT, THE PERFORMANCE OF A TWO-PHASE CLOSED THERMO-SIPHON (HEAT PIPE) WITH WATER AS THE WORKING FLUID FOR THERMAL CONTROL BATCH REACTOR WAS STUDIED. AND THE EFFECT OF SOME OPERATION VARIABLES SUCH AS TIME, INPUT HEAT POWER, FILLING RATIO AND MATERIALS ON THE REACTOR TEMPERATURE WERE STUDIED. THE EXPERIMENTS PERFORMED IN THE FILLING RANGE OF 30%-80% AND INPUT HEAT POWER BETWEEN 200- 1200 WATT AND THE TEMPERATURE UNIFORM IN THE REACTOR, HEATING TIME AND OPTIMAL FILLING RATIO WERE STUDIED. THE RESULTS OBTAINED IN THIS RESEARCH PROJECT WERE THE CONSISTENCY OF THE TEMPERATURE INSIDE THE REACTOR AND THE OPTIMAL FILLING RATIO. ALSO, THE RESULTS OF THIS EXPERIMENT ARE USEFUL IN DESIGN, OPTIMIZATION OF HEAT PIPE AND CONTROL OF REACTOR TEMPERATURE.

BIOLOGICAL OXIDATION OF FERROUS IRON IS AN IMPORTANT POTENTIAL IN INDUSTRIAL PROCESSES SUCH AS H2S REMOVAL IN NATURAL GAS, LEACHING OPERATION OR TREATMENT OF ACID MINE DRAINAGE WATER. OWING TO THE FACT THAT BIO-OXIDATION PROCESS HAS HIGH EFFICIENCY AND ECONOMICAL BENEFITS, IT IS EVIDENT THAT WE SHOULD EXPAND OUR KNOWLEDGE IN THIS CASE. THE PURPOSE OF THIS PAPER WAS TO TREAT FE2+ IONS WITH THE USAGE OF THIOBACILLUS FERROOXIDANS IN LABORATORY, AND AFTER FINDING APPROPRIATE RESULTS, WE DESIGNED AN AIR-LIFT BIOREACTOR AND EXPANDED OUR WORK TO THAT VESSEL IN CONTINUOUS MODE.

A CFD K - E MODEL IS PRESENTED FOR TURBULENT MOMENTUM AND HEAT TRANSFER ON A FLAT PLATE. THE LAYER IS SIMULATED FOR BOTH COMPRESSIBLE AND INCOMPRESSIBLE FLOW. MOMENTUM AND HEAT BOUNDARY LAYER THICKNESS, VELOCITY AND HEAT PROFILE ARE COMPARED FOR TURBULENT AND LAMINAR FLOW. THE EQUATIONS ARE SOLVED BY FINITE VOLUME TECHNIQUE IN A CARTESIAN FRAME USING NON UNIFORM GRID IN THE VICINITY OF VISCOUS SUB-LAYER. ALSO A FINE GRID SIZE WAS CHOSEN TO HAVE LESS CPU TIME. IN THIS RESEARCH WE SHOWED THAT THE BOUNDARY LAYER THICKNESS AND FRICTION FACTOR IS GRATER IN COMPRESSIBLE FLOW. THE RESULTS ARE IN GOOD AGREEMENT WITH OTHER PROPOSED EMPIRICAL EQUATIONS AND ALSO PRANDTL & BLASIUS THEORY.

THERMOPHORESIS IS AN IMPORTANT MECHANISM OF MICRO-PARTICLE TRANSPORT DUE TO A TEMPERATURE GRADIENT IN THE SURROUNDING MEDIUM AND HAS FOUND NUMEROUS APPLICATIONS, ESPECIALLY IN THE FIELD OF AEROSOL TECHNOLOGY. THIS STUDY INVESTIGATES THE THERMOPHORETIC DEPOSITION EFFICIENCY OF PARTICLES IN LAMINAR GAS FLOW IN A CONCENTRIC ANNULUS USING THE CRITICAL TRAJECTORY METHOD NUMERICALLY. THE GOVERNING EQUATIONS INCLUDE THE MOMENTUM AND ENERGY EQUATIONS FOR THE GAS AND THE PARTICLE EQUATIONS OF MOTION. THE EFFECT OF THE ANNULUS SIZE AND THE RATIO OF INNER TO OUTER TUBE WALL TEMPERATURE ON THE DEPOSITION EFFICIENCY WERE STUDIED. SIMULATION RESULTS SUGGEST THAT THERMOPHORETIC DEPOSITION INCREASES WITH INCREASING THERMAL GRADIENT, DEPOSITION DISTANCE, AND THE RATIO OF INNER TO OUTER RADIUS.

A TWO-PHASE FLOW CFD MODEL USING VOLUME OF FLUID (VOF) METHOD IS PRESENTED FOR PREDICTING THE HYDRODYNAMICS, HEAT TRANSFER AND MASS TRANSFER OF FALLING FILM FLOW ON INCLINED PLATES, CORRESPONDING TO THE SURFACE OF TEXTURE OF STRUCTURED PACKING. USING THE PROPOSED CFD MODEL THE INFLUENCE OF SOLID SURFACE MICROSTRUCTURE, LIQUID PROPERTIES AND GAS FLOW RATE ON FLOW BEHAVIOR WAS INVESTIGATED. FROM THE SIMULATED RESULTS IT WAS SHOWN THAT UNDER THE CONDITION OF NO GAS FLOW THE LIQUID FLOW PATTERNS ARE DEPENDENT ON THE MICROSTRUCTURE OF THE PLATES, AND PROPER MICRO STRUCTURING OF THE SOLID SURFACE WILL IMPROVE THE FORMATION OF A CONTINUOUS LIQUID FILM. INCREASING THE WETTED AREA RESULTS ENHANCEMENT OF HEAT AND MASS TRANSFER FROM FILM. IT WAS ALSO FOUND THAT LIQUID PROPERTIES, ESPECIALLY SURFACE TENSION, PLAY AN IMPORTANT ROLE IN DETERMINING THE THIN FILM PATTERN. HOWEVER, THERE ARE VERY DIFFERENT LIQUID FILM PATTERNS UNDER THE ACTION OF GAS FLOW. THINNER LIQUID FILMS BREAK EASILY, BUT THICKER LIQUID FILMS REMAIN CONTINUOUS EVEN AT HIGHER GAS FLOW RATE, WHICH DEMONSTRATES THAT ALL FACTORS AFFECTING THE LIQUID FILM THICKNESS WILL AFFECT THE LIQUID FILM PATTERNS UNDER CONDITIONS OF COUNTER-CURRENT TWO-PHASE FLOW. FINALLY IT WAS FOUND THAT ANY CHANGES IN LIQUID FILM PATTERNS INFLUENCE TOO MUCH ON HEAT AND MASS TRANSFER FROM THE FILM.

THE WORLDWIDE CONSUMPTION OF NATURAL GAS IS RAPIDLY INCREASING. IT IS PREDICTED THE NATURAL GAS DEMAND INCREASES AT AN AVERAGE RATE OF 2.4 PERCENT ANNUALLY UNTIL 2030 IN THE WORLD. HOWEVER THIS RATE OF INCREASE IS HIGHER FOR SOME COUNTRIES WITH FAST GROWING ECONOMY LIKE INDIA. TO SATISFY SUCH A DEMAND, THERE ARE SOME PLANS TO TRANSPORT NATURAL GAS FROM SOUTH PARS GAS FIELD, THE LARGEST IRAN'S NATURAL GAS FIELD, TO INDIA. THERE ARE MANY POSSIBLE TECHNOLOGIES FOR TRANSPORTING GAS FROM PRODUCTION FIELDS TO CONSUMING MARKETS. THESE TECHNOLOGIES INCLUDE PIPELINES (PNG), LIQUEFIED NATURAL GAS (LNG), COMPRESSED NATURAL GAS (CNG), NATURAL GAS HYDRATES (NGH), GAS TO LIQUID (GTL), GAS TO COMMODITY (GTC) AND GAS TO WIRE (GTW), I.E. ELECTRICITY. GAS TRANSMISSION PROJECTS ARE SENSITIVE TO TECHNOLOGY SELECTION AND DEPENDING ON THE CAPACITY AND DISTANCE; CHOSEN TECHNOLOGY MAY AFFECT THE ECONOMY OF THE ENTIRE PROJECT NOTICEABLY. IN THIS WORK THE FEASIBILITY OF TRANSPORTING 100 MMSCMD NATURAL GAS FROM PORT ASSALUYEH IN SOUTHERN IRAN TO INDIA USING SOME ALTERNATIVE TECHNOLOGIES SUCH AS PNG, CNG AND NGH HAS BEEN INVESTIGATED. THE RESULTS SHOW FOR THIS CASE, PNG IS THE BEST COST EFFECTIVE METHOD AND CNG AND NGH ARE THE OTHER OPTIONS RESPECTIVELY.

THIS PAPER DEALS WITH AN EXPERIMENTAL AND THEORETICAL INVESTIGATION OF MICROWAVE DRYING OF MOIST KENAF FIBER. A DRYING MODEL [1-3] IS USED TO DETERMINE DRYING PROCESS PARAMETERS (E.G. DRYING COEFFICIENT , LAG FACTOR) AND MOISTURE TRANSFER PARAMETERS ( E.G. MOISTURE DIFFUSIVITY AND MOISTURE TRANSFER COEFFICIENT), AND TO CALCULATE MOISTURE CONTENT DISTRIBUTIONS. EXPERIMENTAL PART INCLUDES THE MEASUREMENT OF MOISTURE CONTENT DISTRIBUTION OF KENAF SLABS WITH 5MM THICKNESS DURING MICROWAVE DRYING AT THE TEMPERATURE 40 C0, 100 C0 AND 200 C0. THE RESULTS SHOWS A APPRECIABLY HIGH AGREEMENT BETWEEN THE MEASURED AND PREDICTED MOISTURE CONTENT VALUES FOR THE CORRELATION.

NOWADAYS, POPULATION BALANCE IS USED AS A POWERFUL ENGINEERING TOOL IN DESIGN ISSUES. DIFFERENT PROCESSES IN CHEMICAL, PETROCHEMICAL, BIOTECHNOLOGY, PHARMACEUTICAL INDUSTRY, ETC. DEAL WITH PARTICLES. IN SUCH PROCESSES PARTICLE OR BUBBLE SIZE DISTRIBUTION (PSD) INFLUENCES THE FINAL PRODUCT QUALITY AND ALSO PROCESS DESIGN. ON THE OTHER HAND SOLUTION TO THE DOMINANT HYDRODYNAMIC AND THERMO-KINETIC EQUATIONS IGNORING THIS DISTRIBUTION WILL MAKE IT IMPOSSIBLE TO ACCURATELY SIMULATE THESE PROCESSES. SOLUTION TO POPULATION BALANCE EQUATIONS (PBE’S) IS NEEDED TO ATTAIN THE PSD. SINCE 1940’S MANY RESEARCHERS HAVE PROPOSED DIFFERENT METHODS FOR EASIER AND ALSO MORE ACCURATE SOLUTION OF PBE’S. ONE OF THE MOST COMMON AND FAMOUS OF THESE METHODS IS THE CLASSES METHOD (CM). HOWEVER, AS THIS METHOD REQUIRES A LARGE NUMBER OF CLASSES TO GIVE A REASONABLE RESULT, IT NEEDS A HUGE AMOUNT OF CALCULATIONS AND TIME. TO OVERCOME THIS PROBLEM, IN THIS PAPER A NEW VARIANT OF CM IS PROPOSED IN WHICH PARTICLES IN DIFFERENT CLASSES ARE TRANSFORMED TO NEW CLASSES IN TWO STEPS. IN THE FIRST STEP, THE PARTICLES ARE AGGLOMERATED AND BROKEN UP TO FORM THREE PARALLEL TYPES OF GROUPS, NAMELY: GROUPS FORMED FROM AGGLOMERATED PARTICLES; GROUPS FORMED FROM BROKEN UP PARTICLES AND FINALLY A GROUP FORMED FROM NON-ALTERED PARTICLES. IN THE SECOND STEP, THESE PARALLEL GROUPS ARE COMBINED TO REDEFINE CLASSES FOR NEXT TIME STEP. FINALLY, RESULTS OF THIS METHOD, WHICH COULD BE CALLED PARALLEL GROUPS CLASSES METHOD (PGCM), FOR DIFFERENT COALESCENCE AND BREAKAGE KERNELS ARE COMPARED WITH THOSE OBTAINED USING ANALYTICAL SOLUTION AND CM. EXCELLENT AGREEMENT OF RESULTS OF PGCM WITH ANALYTICAL SOLUTION REVEALS ITS EFFECTIVENESS AND ACCURACY; WHICH WILL GIVE IT AN ADVANTAGE OVER CM.

THE APPLICATION OF COMBINED ELECTROMAGNETIC RADIATION AND HOT AIR IS GAINING MOMENTUM IN FOOD PROCESSING. A COMBINED INFRARED AND HOT AIR HEATING SYSTEM WAS DEVELOPED FOR THE DRYING OF VEGETABLES. SET OF COUPLED HEAT AND MASS TRANSFER EQUATIONS ARE DEVELOPED TO PREDICT THE EFFECT OF INFRARED RADIATION (IR) IN A FLUIDIZED BED WITH INERT PARTICLES FOR DRYING OF A SINGLE SPHERE SOLID. A TWO LAYER MODELS WERE INTRODUCED FOR GREEN PEAS, A PENETRATION LAYER AND A CONDUCTION LAYER MODEL. COMPARISON OF THE RESULTS SHOWED THAT THE PREDICTED MODEL AGREED WELL WITH THE EXPERIMENTAL RESULTS WITH A MAXIMUM ERROR OF 5% AND 9% FOR AVERAGE MOISTURE CONTENT AND TEMPERATURE RESPECTIVELY. THE MODEL IS CAPABLE OF REASONABLY PREDICTING TEMPERATURE, MOISTURE CONTENT AND SHRINKAGE DISTRIBUTION INSIDE A PARTICLE.

VOLATILE ORGANIC COMPOUNDS (VOCS) EMITTED FROM STORAGE FACILITIES PLAY A KEY ROLE IN FORMING GROUND-LEVEL OZONE, WHICH CAUSES BREATHING PROBLEMS FOR HUMANS AND DAMAGES PLANTS. IN THIS PAPER, THE AMOUNT OF THE VOLATILE ORGANIC COMPOUNDS (VOCS) WHICH IS EMITTED FROM AN INDUSTRIAL EXTERNAL FLOATING ROOF TANK IS ESTIMATED PRACTICALLY AND ALSO BY USING THE RELATIONS WHICH ARE PROPOSED BY AMERICAN PETROLEUM INSTITUTE (API). FOR THIS PURPOSE THE LEVEL OF THE CONSIDERED LIQUID IN THE TANK AND ITS TEMPERATURE ARE MONITORED AND RECORDED FOR A PERIOD OF 35 DAYS. COMPARISON OF THE OBTAINED PRACTICAL DATA WITH THOSE PREDICTED BY API RELATIONS UNDER THE SAME OPERATING, GEOGRAPHICAL AND METEOROLOGICAL CONDITIONS, SHOWS THAT THE PRACTICAL DATA ARE HIGHER THAN PREDICTED VALUES. THESE RESULTS IN THOSE SAME ACTIONS SHOULD BE MEASURED TO LOWER THE RATE OF EMISSION OF VOCS FROM THE TANK BY IMPROVING THE SEALS OR CONSIDERING THE PROBLEM OF SEEPAGE FROM THE TANK.

IN THE PRESENT WORK, THEORETICAL AND EXPERIMENTAL EVALUATION OF THE EFFECT OF SOLID DESICCANT WHEEL AND OPERATION CONDITIONS ON THE PERFORMANCE OF DESICCANT DEHUMIDIFICATION SYSTEM HAS BEEN CARRIED OUT. A NEW MODEL FOR DESICCANT WHEEL HAS BEEN PRESENTED. IN THE THEORETICAL PART OF THIS STUDY, A MATHEMATICAL MODEL HAS BEEN DEVELOPED WHERE ITS OUTPUT RESULTS ARE COMPARED WITH THE EXPERIMENTAL DATA. THE EFFECT OF DIFFERENT DESIGN PARAMETERS AND OPERATING CONDITIONS ON THE ADSORPTION AND THE REGENERATION PROCESSES IS DISCUSSED. THE EFFECT OF REGENERATION AIR TEMPERATURE, THE PROCESS AIR AND REGENERATION AIR INLET HUMIDITY, THE ROTATIONAL SPEED, THE PROCESS AND REGENERATION AIR VELOCITY (OR FLOW RATE), THE BED LENGTH, PERFORMANCE ANALYSIS, ETC. ON THE AMOUNT OF WATER ADSORBED/DESORBED IN A CYCLE IS INVESTIGATED.

GAS–SOLID FLUIDIZED BED REACTORS HAVE MANY INDUSTRIAL APPLICATIONS AND HAVE BEEN STUDIED BY MANY RESEARCHERS. IN THIS STUDY, THE 2D HYDRODYNAMICS OF FLUIDIZED BED WAS INVESTIGATED BY USING CFD ANALYSIS. TO PERFORM THE SIMULATION OF FLUIDIZED BED, THE TWO-FLUID MODEL (TFM) BY THE KINETIC THEORY OF GRANULAR FLOW (KTGF) WAS USED TO DESCRIBE THE SOLID PARTICLES AS CONTINUUM PHASE. ALSO FOR THIS SYSTEM (DENSE GAS-SOLID FLUIDIZED BED), AN ALGEBRAIC GRANULAR ENERGY-BALANCE EQUATION IS PROPOSED TO DETERMINE THE GRANULAR TEMPERATURE INSTEAD OF SOLVING THE FULL GRANULAR ENERGY BALANCE EQUATION. THIS SIMPLIFICATION DOES NOT LEAD TO DIFFERENT RESULTS, BUT SIGNIFICANTLY REDUCES THE COMPUTATIONAL EFFORT OF THE SIMULATION. THE COMPUTATIONAL FLUID DYNAMICS SIMULATION RESULTS WERE COMPARED TO BUBBLING FLUIDIZED BED CONTAINING THE AVERAGE SPHERICAL GLASS BEADS OF 275 MICRON IN DIAMETER. THE RESULTS OF THIS SIMULATION FOR LOCAL VOIDAGE AND LOCAL SOLID VELOCITY ARE IN A GOOD AGREEMENT WITH THE EXPERIMENTAL DATA AND SHOW A SUITABLE TREND IN COMPARISON WITH THE THEORETICAL FINDINGS. WHILST THE SUPERFICIAL GAS VELOCITIES WERE 0.1, 0.38 AND 0.48 M/S.

TUBE INSERTS ARE USED AS HEAT TRANSFER ENHANCEMENT DEVICES IN APPLICATIONS: RETROFITTING AND NEW DESIGN OF SHELL AND TUBE HEAT EXCHANGERS. IN THIS PAPER, HELICAL-WIRE-COILS FITTED INSIDE A ROUND TUBE HAVE BEEN EXPERIMENTALLY STUDIED IN ORDER TO CHARACTERIZE THEIR THERMO HYDRAULIC AND FOULING BEHAVIORS IN TURBULENT FLOW REGIME. THE PRESENT STUDY INTRODUCES A NEW EXPERIMENTAL METHOD TO REVEAL FOR THE FOULING PROCESS OF CACO3 (CRYSTALLIZATION MECHANISM FOR WATER) AND TO STUDY THE EFFECT OF WIRE COIL INSERTS ON FOULING RESISTANCE OF CACO3, HEAT TRANSFER COEFFICIENT AND FRICTION FACTOR. THE FOULING EXPERIMENTS WERE PERFORMED WITH THE REYNOLDS NUMBER SET AT 12,824 WHICH IS CORRESPONDENT TO THE FLOW VELOCITY OF 0.66 M/S IN THE TEST SECTION. THE INLET BULK TEMPERATURE WAS 39OC AND WITH AVERAGE TOTAL HARDNESS 245. BY ADDING OF CALCIUM CHLORIDE (CACL2) AND BICARBONATE SODIUM (NAHCO3) CONTINUOUSLY TO WATER TANK, THE AVERAGE TOTAL HARDNESS KEEP ALMOST CONSTANT. FOULING RESISTANCE RESULTS REPORT FROM THREE WIRE COIL INSERTS WITHIN A GEOMETRICAL RANGE OF HELICAL PITCH 0.1375<P/D<0.2813 AND WIRE DIAMETER 0.0238<E/D<0.0750. THE HEAT TRANSFER AND PRESSURE DROP ARE RESULTS FROM WIRE COILS ARE SHOWN IN TURBULENT FLOW REGIME WITHIN A WIDE FLOW RANGE: 4000<RE<52000 AND ALMOST CONSTANT PRANDTL NUMBER (PR=3.15-4.55). WE PROPOSED A MATHEMATICAL RESTATEMENT ON KERN AND SEATON FOULING MODEL FOR PLAIN AND ENHANCED TUBE (WITH WIRE COIL TYPE1). ALSO NUSSELT NUMBER AND ISOTHERMAL FRICTION FACTOR CORRELATIONS ARE PROPOSED FOR TURBULENT REGIME IN TERMS OF REYNOLDS NUMBER (RE>4500) AND INSERTS GEOMETRY.

LIQUID MEMBRANES WITH IMPRESSIVE PROPERTIES SUCH AS HIGH SELECTIVITY AND EFFICIENT CONSUMPTION OF ENERGY IN SEPARATION PROCESSES SEEM TO BE MORE SUITABLE. OTHER ADVANTAGES SUCH AS VARIETY OF CONFIGURATION AND CARRIERS FOR DIFFERENT APPLICATIONS, SIMPLICITY OF ASSEMBLING AND HIGH RATE OF MASS TRANSFER ARE FACILITATED THE IMPLEMENTATION OF THESE MEMBRANES. CHROMIUM IS ONE OF CONTAMINANTS THAT EXIST IN WASTE WATER OF VARIOUS INDUSTRIES LIKE STEEL, PIGMENT AND LEATHER TANNING. IN THIS PROJECT SEPARATION OF CR (VI) ION BY IMPLEMENTATION OF A BULK LIQUID MEMBRANE USING ALAMINE AS CARRIER, KEROSENE AS SOLVENT, SODIUM HYDROXIDE AS STRIPPING PRODUCT PHASE, DODECANOL FOR PREVENTING FROM JELLYING OF INORGANIC AND ORGANIC PHASES HAVE BEEN INVESTIGATED. EFFECTIVE PARAMETERS ON SEPARATION OF CR(VI)ION INCLUDING FEED PHASE PH, STRIPPING PHASE MOLARITY, MIXER ROTATIONAL RATE IN FEED AND STRIPPING PHASE, VOLUME PERCENTAGE OF CARRIER IN ORGANIC PHASE, PRESENCE/ABSENCE OF SURFACTANT IN ORGANIC PHASE HAVE BEEN STUDIED. IN THE RANGE OF DESIGNED EXPERIMENTAL, THE OPTIMUM CONDITIONS AS FOLLOW HAVE BEEN FOUND: PH=2, STRIPPING PHASE MOLARITY=3, MIXER ROTATIONAL RATE IN BOTH INORGANIC PHASES = 100 RPM, VOLUMETRIC AMOUNT OF CARRIER = 1%, AND PRESENCE OF SURFACTANT.

GAS HYDRATES ARE KNOWN AS ONE OF THE MAIN PROBLEMS IN GAS TRANSPORTATION LINES FROM 1934 TO NOW. THE MAIN RESEARCHES IN THIS FIELD ARE RELATED TO THE HYDRATE FORMATION CONDITIONS AND THE EFFECT OF USING INHIBITORS. FROM EARLY 1990S, THE MAIN FEATURES OF USING GAS HYDRATES IN STORAGE AND TRANSPORTATION OF NATURAL GAS AND SEPARATION OF GAS MIXTURES WERE CONSIDERED. RESEARCH SHOWS THAT 1M3 OF GAS HYDRATES CAN RESERVE 170M3 OF NATURAL GAS IN STANDARD CONDITIONS. THEREFORE, WITH RESPECT TO THE OPERATING CONDITIONS FOR PRODUCTION AND STORAGE, USING GAS HYDRATES FOR STORAGE AND TRANSPORTATION OF NATURAL GAS WITH CONVENTIONAL METHODS (I.E., CNG AND LNG) CAN BE IMPORTANT FROM ECONOMIC POINT OF VIEW. FOR DESIGNING GAS HYDRATES PRODUCTION UNITS, RELIABLE KINETIC AND THERMODYNAMIC MODELS FOR PREDICTION OF HYDRATE FORMATION CONDITIONS IN REACTORS, COMPONENTS COMPOSITION AND HYDRATE STRUCTURE MUST BE AVAILABLE. IN THIS ARTICLE, HYDRATES, TYPES OF ITS STRUCTURE, FORMATION CONDITIONS AND REQUIRED DRIVING FORCE FOR FORMATION AND DIFFERENT KINETIC MODELS ARE INVESTIGATED. THEN, KINETIC MODELS ARE STUDIED AND THE BEST MODEL IS SELECTED AND SIMULATED. COMPARING THE SIMULATED RESULTS WITH EXPERIMENTAL DATA SHOWS THAT THE KINETIC MODEL OF FIROOZABADI AND KASHCHIEV (2003) WITH SOME MODIFICATION HAS THE BEST AGREEMENT WITH EXPERIMENTAL DATA.

CHEMICAL RECYCLING OF POLY (ETHYLENE TEREPHTHALATE), PET WASTAGE HAS BEEN INVESTIGATED IN THIS WORK. THE AIM OF THIS WORK IS TEREPHTHALIC ACID AND ETHYLENE GLYCOLS RECOVERY FROM PET WASTE. THIS PROCESS HAS BEEN DONE IN TWO STAGES. FIRST STAGE WAS REACTION OF PET WASTE WITH SODIUM HYDROXIDE THAT PRODUCED ETHYLENE GLYCOL AND SODIUM TEREPHTHALATE SOLUTION AND SECOND STAGE WAS REACTION OF OBTAINED SODIUM TEREPHTHALATE WITH HYDROCHLORIC ACID THAT LED TO TEREPHTHALIC ACID PRODUCTION. VARIABLES SUCH AS OPERATIONAL TEMPERATURES AND PRESSURES, AND QUANTITY OF CONSUMING SODIUM HYDROXIDE AND HYDROCHLORIC ACID HAVE BEEN STUDIED. THE NEEDFUL QUANTITIES OF SODIUM HYDROXIDE AND HYDROCHLORIC ACID WERE ACHIEVED 50GR AND 166GR PER 1KG OF PET WASTE, RESPECTIVELY. OPERATIONAL TEMPERATURE AND PRESSURE WAS ACHIEVED 180OC AND 1.5BAR IN THE FIRST STAGE RESPECTIVELY.