Thermoeconomic analysis of an internal combustion engine cogeneration system using syngas of a downdraft gasifier.
José Ramón Copa Rey1; Celso Eduardo Tuna1; Elbis Despaux Shelton2; Jose Luz Silveira1
1 Universidade Estadual Paulista (Unesp); 2 Universidad de Oriente Cuba
doi:10.20906/CPS/CON-2016-0623
Resumo
The paper shows the results achieved in the evaluation of the different alternatives of a cogeneration model consistent of a downdraft gasifier coupled to an internal combustion engine (ICE) and two heat exchangers water/gas. The exergoeconomic analysis is based on the method developed by Silveira et al. 1999, available in the literature. The composition of the synthesis gas is obtained by applying the model of balance developed by Zeneal et al. 2001, assuming a temperature of 800 °C, for downdraft gasifier. The synthesis gas produced is cooled in a heat exchanger water/gas to generate hot water at 80 °C and then is used in ICE to generate electric power, heat of the exhaust gases is used in a second heat exchanger to produce hot water at 80 °C. This study considers three biomass: sugarcane bagasse, rice husks and pine. From the point of view of the second law of thermodynamics, the overall efficiency of the system for bagasse is 13.5 %, for pine is of 13 %, and for rice husk reached to 13.8 %, the efficiency of power generation varies from 25.76 %; 22.04 % to 25.49 % for the bagasse, pine and rice husk respectively and the efficiency of generating hot water varies from 8.02% to 12.82 % for the three biomasses studied. The cost of the synthesis gas varies from 0.043 to 0.16 US$/kWh, the electricity production cost varies from 0.048 to 0.22 US$/kWh and the hot water production is located between 0.002 to 0.014 US$/kWh. Recovery time of the investment (payback), the interest rate is 6%, is between 5 and 6 years.
Palavras-chave: Renewable energy; exergoeconomic analysis; gasification; cogeneration