FLUIDIZED BED GASIFICATION OF GARDEN WASTES BATCH : B12 S.VISHNURAJA G.RAJARAJAN G.SATHEESHKUMAR S.SURESHKUMAR Under the Guidance of Mr.S.VIJAJARAJ M.E.,(Ph.D.,) Asst.PROF.ESSOR, Dept of Mech

STATEMENT ABOUT PROBLEM Generally garden waste (crushed leafs) are bio degradable, they are digested in soil without any energy conversion The garden waste are highly available in nature The garden waste contain some amount of energy we should burn to obtain it Our proposed idea will reduce some amount of present fuel demand

OBJECTIVE  To utilize the agricultural waste from paddy fields like paddy straw for synthetic gas production to replace the conventional energy requirements.  To satisfy the growing energy demand  To control the CO 2 emission

PROCESS  Segregating and Chopping the dried leafs from garden waste and crushing the leafs into fine particles The crushed particle are fed into the FBG and it is gasified Air is being supplied from the other side of FBG with the controlled valve. This is done by using a blower which supplies the required air A amount air supplied can be varied by adjusting the valve attached blower The gasification is controlled effectively by variation in the air supply The combusted gas is being sent to the cyclone separator where it is purified.

INTRODUCTION  Coal is an oldest fuel and still used on large scale throughout world for power generation. Most of the power industries are shifted from oil to coal. But the availability of coal is limited amount.  So there is a need for non- conventional energy sources to over come this energy demand. FuelAvailabilit y Consumpt ion Coal Oil Natural gas 80,950 million tons 1100 billion tons 350 billion tons 200 million tons/year 40 million tons/year 14 million tons/year

Bio-mass  Bio mass is a organic matter produced by plants, both in land and water. It includes forest crops and animal manure. It is an alternative source of energy in our country. It is the solar energy stored by the way of photosynthesis Solar energy Photosynthesis Bio-mass Energy generation

Method of obtaining biomass Method of obtaining energy from BIO-MASS combustion Thermo chemical Combustion 1.Gasification 2.liquification Bio-chemical Combustion 1.Anerobicdigestion 2.Fermentation

Gasification: Gasification is a process that convert carbonaceous material such as coal, petroleum, biofuel or biomass, into carbon-monoxide and hydrogen by reacting the raw material such as house waste or compost at high temperature with the controlled amount of O 2 and stream. The resulting gas mixture is called synthesis gas.

THEORY OF GASIFICATION: The production of generator gas (producer gas) called gasification, is partial combustion of solid fuel (biomass) and takes place at temperature of about 1000˚C. The reactor is called a gasifier. The combustion products from complete combustion of bio mass generally contain nitrogen water vapor, carbon dioxide and surplus of oxygen. However in gasification where is a surplus of solid fuel (incomplete combustion) the products of combustion are combustible gases like carbon monoxide (CO), hydrogen (H2), and traces of methane and non useful products like tar and dust

Gasification Principle In principle, gasification is the thermal decomposition of organic matter in an oxygen deficient atmosphere producing a gas composition containing combustible gases, liquids and tars, charcoal, and air, or inert fluidizing gases. Typically, the term "gasification" refers to the production of gaseous components, whereas pyrolysis, or pyrolization, is used to describe the production of liquid residues and charcoal. The latter, normally, occurs in the total absence of oxygen, while most gasification reactions take place in an oxygen-starved environment.

Fluidized bed gasifier

INERT MATERIAL USED IN THE FBG SYSTEM 1. Sand 2.Lime stone or dolomite 3.Fused alumina and 4.Sintered ash

 In the fluidised bed combustor the paddy straw is being burnt which is stocked from feed stock.  Air is being supplied from the other side of FBC with the controlled valve.  This is done by using a blower which supplies the required air  A amount air supplied can be varied by adjusting the valve attached blower  The gasification is controlled effectively by variation in the air supply  The combusted gas is being sent to the cyclone separator where it purified.

Cyclone separator  It is a mechanical type of dust collector a high velocity gas stream carrying the dust particles enters at high velocity and tangential-to the conical cell  This produces a whirling motion of the gas within the chamber and throws heavier dust particles to the sides and fall out of gas stream and collected at the bottom of the collector.

Data Needed to Design the System  The ultimate analysis of fuel  The proximate analysis of fuel  Bed material characteristics  Size distribution of particles  Porosity of the material  Density of the materials  Sphericity of the particle  Paddy straw is choosen as a fuel for designing a system the to choose the paddy straw is ash fusion temperature of paddy straw is high and so there is no risk of clinger formation in the bed.

Design Steps  Calculation of fuel feed Rate  Calculation of reactor dimensions  Design of distributor plate  Calculation of minimum fluidization velocity  Design of duct  Design of blower

PROXIMATE ANALYSIS BIOMASS FUELS NEEM LEAF BASSIA LONGFONIA GRASS POWDER Moisture% Ash% Volatile matter% Fixed carbon% Gross calorific value in Kcals/kg

ULTIMATE ANALYSISBIOMASS FUELS NEEM LEAFBASSIA LONGFONIA GRASS POWDER Moisture% Mineral matter % Carbon % Hydrogen % Nitrogen % % Oxygen by difference %

DESIGN OF FLUE GAS DUCT: Temperature=650˚C Amount of gas formed=fuel+air-ash = = Kg/Kg of fuel Exhaust Gas density = Kg/m3 Q= /0.2279=60.55 m3/hr

CYCLONE SEPARATOR DESIGN STEPS GENERAL PURPOSE FLAT TOP DESIGN CALCULATE INLET AREA A=Q/CV CALCULATE INLET DIAMETER D=√(A/Π) BODY DIAMETER= INLET DIAMETER×4 BODY HEIGHT= INLET DIAMETER×2.33 CONE HEIGHT= INLET DIAMETER×4 CLEAN AIR OUTLET DIAMETER=INLET DIAMETER×2 WELL LENGTH=BODY HEIGHT

CYCLONE SEPARATOR 1: Inlet area A Where d=diameter of exhaust duct= m Inlet area A= *10 -3 m 2 Inlet diameter D= m Body diameter =D*4 = m Body height= D*2.33 = m Cone height= D*4 = m Clean gas outlet diameter= D*2 = m

CYCLONE SEPARATOR 2: Inlet area A Where d=diameter of exhaust duct= mm Inlet area A= *10 -3 m 2 Inlet diameter D= m Body diameter =D*4 = m Body height= D*2.33 = m Cone height= D*4 = m Clean gas outlet diameter= D*2 = m

THE DESIGN STEPS: CALCULATION OF FUEL FEED RATE: Stoichiometric air required for gasification =100/23(8/3*C+8*H2+S -O2 ) =100/23((8/3*0.39) + (8*0.048)+(1* )) =5 Kg of air/Kg of PS

CALCULATION OF ACTUAL AIR REQUIRED Gasification is conducted at the obtained minimum fluidization velocity of 0.95 m/s For ER=0.15 ER=Actual air required per kg=ER* stoichoimetric air required =0.15*10.51 =1.57 kg/hr Volume flow rate of air Cd=0.63 D=16.2mm Volume = Area*3600*V f =0.0144*3600*0.952 =49.37 m 3 /hr Mass=volume* density; at 40º C =49.37×1.125 Mass air supplied=55.54 kg/hr Mass of fuel gasified = 55.54/1.57 = kg/hr NEEM LEAF FUEL CALCULATION: CALCULATION OF FUEL FEED RATE Stoichiometric air required for gasification =10.51 kg/kg of air

Volume flow rate of air Cd=0.63 where d=16.2mm Volume = Area*3600*V f =0.0144*3600*0.952 =49.37 m 3 /hr Mass=volume* density; at 40º C =49.37×1.125 Mass of air supplied =55.54 kg/hr

MASS FLOW RATE AND AIR FUEL RATE OF NEEM FLUIDIZATION RATIO VELOCITY EQULIZATION RATIO- ER Mass of fuel 35.37kg/hrMass of fuel 17.63kg/hr Mass of air kg/hr

MASS FLOW RATE AND AIR FUEL RATE OF MAHUVA AND GRASS FLUIDIZATION RATIO- FR EQULIZATION RATIO- ER Mass of fuel 36.30kg/hrMass of fuel kg/hr Mass of air kg/hr FLUIDIZATION RATIO- FR EQULIZATION RATIO- ER Mass of fuel kg/hrMass of fuel 17.64kg/hr Mass of air kg/hr

DESIGN OF BLOWER: Pressure drop in the air duct: Pressure drop in the air duct= 4flv^2 / 2gd f=0.0036*0.26(Re)-0.4 Re=vdρ/μ Where Re=Reynolds number=22559 F= Assume the length of air duct=3 m The pressure drop in the air duct=57.55 per mm of WC

PRESSURE DROP IN THE DISTRIBUTOR PLATE: Pressure drop in the nozzle=(1.5v2ρ/2g) Where v=velocity of air in the nozzle outlet=48 m/s Density (ρ) of air=1.125 Kg/m3 Pressure drop= mm of WC PRESSURE DROP IN BED: Orifice diameter dor= 3 mm Equivalent diameter of the bed D =0.12 m Minimum distributor pressure drop

Δpo= Δpb( (1-exp(-D)/2hmf)) Δpb bed pressure drop= ρs g hmf (1-εmf) hmf –height of the expanded bed= 170 mm εmf –sphericity = 0.4 Δpb = 2100*9.81*0.17(1-0.4) = mm of WC Δpo =2101.3*( (1-exp(-0.12/2*0.17))) Δpo = mm of WC

PRESSURE DROP IN CYCLONE SEPARATOR: Pressure drop in cyclone separator 1 =4.26 mm of WC Pressure drop in cyclone separator 2 =1.20 mm of WC Total pressure drop= = 407 mm of WC

D =Equivalent diameter of the bed Minimum distributor pressure drop Δp o = Δp b ( (1-e (-D)/2hmf) ) Δp b= bed pressure drop= ρ s g h mf (1-ε mf ) h mf =height of the expanded bed ε mf =sphericity Power required (P) ή=Blower efficiency = 40% P=0.067 kW Therefore the required blower capacity is 1 HP

EXPERIMENTAL SETUP

ISOMETRIC VIEW

PLANE VIEW

OBSERVATIONS

COLD TEST S.No Bed Height (mm) Expanded Bed Eight (mm) Bed Pressure Drop (mm) Superficial Velocity (m/s)

EXPERIMENTAL VALUE OF HOT TEST S.NoFuel used Equiva lence ratio Mass Flow Rate Of Air (Kg/hr) Fuel Feed rate In (Kg/hr) Pr. Drop In The distributor plate mm of WC Pr. drop in the bed mm of WC 1.Neem leaf Mahuva leaf Grass

EXPERIMENTAL VALUE OF NEEM LEAF FOR EQUIVALENCE RATIO: 0.15 SNO Time sec Bed temperature ˚C Free board temperature ˚C

EXPERIMENTAL VALUE OF NEEM LEAF FOR EQUIVALENCE RATIO: 0.30 SNOTime sec Bed temperature ˚C Free board temperature ˚C

Thank you