Steam gasification of wood biomass in a fluidized biocatalytic system bed gasifier: A model development and validation using experiment and Boubaker Polynomials Expansion Scheme BPES

One of the most important issues in biomass biocatalytic gasification is the correct prediction of gasification products, with particular attention to the Topping Atmosphere Residues (TARs). In this work, performedwithin the European 7FP UNIfHY project, we develops and validate experimentally a model which is able of predicting the outputs,including TARs, of a steam-fluidized bed biomass gasifier. Pine wood was chosen as biomass feedstock: the products obtained in pyrolysis tests are the relevant model input. Hydrodynamics and chemical properties of the reacting system are considered: the hydrodynamic approach is based on the two phase theory of fluidization, meanwhile the chemical model is based on the kinetic equations for the heterogeneous and homogenous reactions. The derived differentials equations for the gasifier at steady state were implemented MATLAB. Solution was consecutively carried out using the Boubaker Polynomials Expansion Scheme by varying steam/biomass ratio (0.5-1) and operating temperature (750-850°C).The comparison between models and experimental results showed that the model is able of predicting gas mole fractions and production rate including most of the representative TARs compound

Optimization of Working Conditions for Perovskite-Based Gas Sensor Devices by Multiregression Analysis

Environmental degradation and resource depletion drive scientific research priorities to develop technologies for sustainable productive systems. Among them, chemical sensing technology plays a key role for regulating energetic, ecological, and productive efficiency by monitoring and controlling the industrial processes. Semiconducting metal oxide sensors are particularly attractive technology because of their simplicity in function, small size, and projected low cost. The aim of this work is to synthesize Ti-substituted lanthanum ferrite perovskite, LaFe0.8Ti0.2O3, in order to develop a resistive sensor device for monitoring carbon monoxide. Since sensor performances are affected by experimental factors, such as temperature, target gas concentration, and gas flow rate, the aim of the authors was to define the optimum working condition by performing multiple regression analyses. The investigated ranges of operating conditions were temperature from 300 to 480°C, carbon monoxide concentration from 100 to 200 ppm, and inlet-gas flow rate from 40 to 100 cm3/min. The results confirm that the applied systematic analysis is a powerful method for studying the direct and indirect effects of every experimental factor on sensor performance and for computing mathematical models with predictive ability, that are useful tools for defining the optimum chemiresistors' operating conditions. In addition, mathematical models are able to be used as multiple-factor surface calibration for restive gas sensor devices

Cold model testing of an innovative dual bubbling fluidized bed steam gasifier

Biomass gasification by a dual fluidized bed reactor is a very promising process to produce a hydrogen rich syngas from biomass wastes. In this process, the bed material circulation must be enough to transport heat from the combustor to the steam gasifier, and at the same time siphons/loop-seals must be properly designed to avoid gas leakage between the two reactor chambers (such as N2 from the combustor to the gasifier). A cold model of an innovative pilot scale dual bubbling fluidized bed gasifier (100 kWth as biomass input) has been realized. The Hybrid Lagrangian Particle Tracking (HLPT) technique and tracer gas analysis, both applied to the cold model, have been used to evaluate the flow rate of bed material circulation and the gas leakage between the steam gasification and the combustion chambers. The results have shown that the bed material circulation is 2–3 times the minimum required to assure allothermal gasification, while gas leakage is negligible for every operating condition evaluated experimentally