Controle e avaliação de um conjunto gaseificador-combustor de fluxo concorrente, utilizando como combustível a biomassa de lenha de eucalipto / Control and evaluation of a set gasifier-combustor with co-current flow using eucalyptus wood as a fuel

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Recently, concern has grown considering environmental issues associated with the preservation of natural resources with the intention of improving the present and future quality of life. Biomass gasification shows to be a sustainable technology for power generation with low greenhouse gas emissions. One of the problems by using the gasifier for air heating purposes in poultry facilities is the waste of energy during the day, since the equipment does not have control of the thermal power generated. During this period, the temperature difference between the air outside and the birds inside the building is lower when compared with the nocturnal period. Another way to control the temperature is the shutdown of the system, which requires the constant attention of the operator. Thus, there is a potential for energy savings if the thermal power could be controlled according to the demand, which can be represented by the temperature gradient. The purpose of this study was to evaluate the control of a set combustor-gasifier with downdraught co-current flow, through the control of speed of the fan engine and also controlling the contributions of primary and secondary air in the combustor. The experiment was carried out in the Energy and Preprocessing Areas of the Department of Agricultural Engineering, at the Federal University of Viçosa, Viçosa, Minas Gerais State. The air heating system was composed of a biomass gasifier with co-current air flow connected to a combustor for burning the gas produced. At the combustor exit was a centrifugal fan with capacity for 20 m3.mim-1 552 W, 220 V threephase motor. The exhaustion and environmental air temperatures were measures by thermocouples K (Cromel + Alumel). Eucalyptus wood biomass, with an average diameter 6.0 2.0 cm average length 4.0 2.0 cm was used as fuel to the gasifier. The areas used for the primary air contributions to the combustor were 0 and 112 cm, and for the secondary air contribution to the combustor were: 0, 180 and 360 cm. The frequencies chosen and applied by the frequency inverter to the motor were from 10 to 60 Hz, with steps of 5 Hz, obtaining a range of average actual power from the motor from 93 to 326 W. The difference of temperature and average actual power from the motor was measured with the combustor air inlets closed were respectively 127.7 C and 233 W. When the combustor air inlet area was 472 cm2, 10 C and 97 W were found. After evaluating the results, it could be concluded that: the control of exhaustion air temperature can be done by controlling the air flow to the combustor or changing the speed of the fan motor. The variation of the input area of air in the combustor implicates in a variation in the temperature of the exhaustion air. However, controlling the speed of the fan motor provides a change in exhaustion air temperature and a decrease in electric power consumption. The operation of the gasifiercombustor using a frequency inverter combined with the combustor openings of air eases the consumption production of thermal power.

ASSUNTO(S)

controle biomassa energizacao rural gasifier gaseificador biomass control

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