Explain The Adiabatic Reaction Temperature Of Pyro-Oxidation Zone
(Barman, Ghosh, and De) also considered the formation of tar and methane reforming reaction in the pyro-Oxidation zone.
The adiabatic reaction temperature is found out by considering heat balance in the zone.
Enthalpy of reactants + Heat loss=Enthalpy of products =
The heat loss from the oxidation zone was found to be around 10% by Chern(cite).
TO is the temperature of biomass fed to the gasifier and Ta is the temperature of air fed to gasifier.
Solving the above equations simultaneously gives us the no. of moles of each of the gases in the pro-oxidation zone per mole of biomass and the temperature of the pyro-oxidation zone.
The % of each of the components …show more content…
In this model no any chemical reaction is considered.(Barba et al.) modelled gasification by considering it to occur in two steps, in the first of which the biomass is decomposed at high temperature to give primary gas and carbonaceous residue and in the second there is modification in primary gas due to water gas shift reaction and steam reforming reaction. The total Gibbs free energy of a system is a function of Gibbs free energy of each of the components. For minimizing the Gibbs free energy, the mass of each individual element present in the gaseous mixture is considered. The amount of an element in the resulting gas mixture produced must be equal to its amount obtained from the ultimate analysis of the …show more content…
The kinetics model is able to predict the rate of each of the reactions and the temperature variations along the length of the gasifier.(Wang and Kinoshita) modelled the biomass gasification considering kinetics of the surface reactions and assumed the initial concentrations of before char reduction to be equal to zero. The gasifier was divided into Flaming Pyrolysis, Char Reduction and inert char zones. In the Char reduction zone the reaction rate is much greater than in the flaming pyrolysis zone. The temperature of the reduction zone is around and hence no equilibrium is achieved in the reduction zone.
(Sharma) modelled the gasification for a downdraft gasifier by dividing it into two zones: the first zone in which drying, pyrolysis and oxidation occur and the second in which char reduction takes place. The reduction zone is modelled based on finite rate kinetics.
The reactions taking place in the reduction zone are: The equilibrium constants for these reactions are obtained similarly as for the reactions of pyro-oxidation