No abstract

Significant high levels of available waste tires in Brazil, which reached approximately 473 thousand tons in 2015, offer an attractive potential for their use as fuel in advanced thermal conversion processes. Technologies for energetic valorization of waste tires were reviewed and two alternatives based on updraft gasification in a modified reactor design were proposed. First of all, a large-scale updraft gasifier on IGCC (Integrated Gasification Combined Cycle) was considered for the gasification of the derived fuel from waste tires, capable to produce between 10.8 and 16.1 MJ of electric energy per kg of derived fuel from waste tires fed to the reactor. The second alternative considered a small-scale updraft gasifier feeding an internal combustion engine, coupled to an electricity generator for the production of up to 8.2 MJ of electric energy per kg of derived fuel from waste tires fed to the reactor. Implementation of these technologies will allow energetic valorization of waste tires in Brazil, solving their disposal problems, creating jobs, reducing negative disposal environmental impacts in landfills, and increasing distributed generation of electricity.

This paper is focused on the study of fluid-dynamic behavior of mixtures of the sugarcane bagasse particles and quartz sand in a transparent fluidized bed column. The minimum fluidization velocity (V mf ) was determined by different mean particle diameters and different mass fractions in the mixture compositions. The values of V mf increased with amount of biomass in the mixture increased as well as with the size of the biomass particles in the range of 9.5 ! d pb > 0.225 mm. Binary mixtures with diameter ratios biomass/sand 1 had a (V mf ) almost constant as a function of mass fraction of biomass. It is suggested a practical upper limit of biomass fraction in the mixtures less than 5% of the overall bed mass to obtain a good mixing and uniform distribution in the bed. New correlations were developed to predict the values of (V mf ). It was found that the present proposed correlation predicted the (V mf ) for binary mixtures of sugarcane bagasse and sand particles more accurately than other correlations reported in the literature available.

In the present work is performed a technical and economic analysis of a combined heat and power 9 generation system (CHP), designed to operate coupled to an internal combustion engine (ICE) fuelled with 10 biomass producer gas, in order to generate electricity and hot water for isolated communities of power 11 distribution network. In the proposed system configuration, the energy of the engine's hot exhaust gases is 12 recovered (cogeneration), making this system more attractive in relation to conventional configurations, which 13 are normally used to produce solely mechanical and electrical energy. The proposed system is composed of a 14 modified downdraft gasifier, Imbert technology; coupled to an internal combustion engine, model ZIL−130. 15The system is designed and built in the laboratory of fluid mechanics at the University of Camagüey. The 16 feedstock studied for the gasifier was Dichrostachys Cinerea, collected in neighboring areas to the proposed 17 place of installation. The main energy flows and the costs associated with the production of producer gas were 18 determinate. From the mass and energy balances, the thermal and electric efficiencies of the cogeneration 19 systems resulted in η hw =32.4% and η ge =23.4% respectively, whereas the overall efficiency led to η global =33.3%. 20 In the economic analysis were studied the Internal Rate of Return (IRR), the Net Present Value (NPV) and time 21 of return on investment (TRI) or payback, considering a project lifespan of 15 years. For the annual interest rate 22 of 12%, the electricity should be sold at 0.3USD/kWh in order to the project be feasible. The IRR resulted in 23 12%, the NPV was 20,571 USD and payback period resulted in 5.3 years. In the proposed configuration, the 24 system consumes 1.46 kg of biomass per kWe produced, with a maximum cost of generated electricity of 0.022 25 USD/kWh.26 27 Nomenclature ݉ሶ − mass flow rate [kg/s or m 3 /h] n −r.p.m cw − cool water T − temperature [K] HHV-High hating value exh − flue gas N − power [kW] LHV-low heating value [kJ/kg or MJ/m 3 ] elec − electricity C 1 ,C 2 ,C 3 − coefficients of the engine Subscript e-electric ge − specific fuel consumption[g/kWh] bio − biomass net -net Tr − torque [kgf.m] i− each parameter of engine gas-producer gas Cp − average specific heat [kJ/kgK] N − nominal parameter of engine csys-cogeneration systems E − energy [kWh] out − outlet Superscripts I − Investment [USD$] in − inlet t-amortization periods C M − maintenance cost [USD$/kWh] hw − hot water Greek symbols C − cost [USD$/kWh] hw HE 1,2,4 -hot water in heat exchangers ߟ− efficiency Fp − adjustment factor air HE3 -hot air in heat exchanger 3 r-annual interest rate th − thermal q -factor eng/ger − engine generator