fuels in the world, and the research about the utilization of primary alcohols as spark ignition engine fuels proved interesting as a complement or substitute for gasoline automotive engines. The use of ethanol as an automotive fuel has been known in former times, indeed it was not widely used due to the high production costs of this alcohol in several countries. At that time, the technology of ethanol drawn from sugarcane was well known in Brazil and the Federal Government decided to create the National Ethanol Program (PROALCOOL) in order to encourage the research of ethanol as an automotive fuel. Industry and University started to develop technologies for that. In Brazil, the use of ethanol-powered vehicles has reached its peak in the eighties, but a standing point occurred in the last decade of the twentieth century. Due the market opening which took place in Brazil at the beginning of 90s, a large number of foreign petrol cars started to be sold in the country. At the beginning of the current century, Brazil witnessed the coming of the flex-fuel engine technology. The fuel-flexible engines may operate with 100 % of gasohol (an of-the-shelf blend of 18-25 % of anhydrous ethanol on gasoline in volume), 100 % of hydrous ethanol, or any blend of these fuels. Several investigations of performance, combustion, and emissions have been performed in the last years in order to assess the behavior of both engine and fuel blends in fuelflex engines and for pure petrol-designed engines. Reference [1] studied a four-cylinder, four-stroke, 8-valve flexfuel engine. The authors carried out the tests using a 78 % gasoline-22 % ethanol blend and commercial hydrous ethanol. The experiments were performed according to NBR-ISO 1585 standard under steady state starting from 6500 down to 1500 rpm in steps of 250 rpm. The measured power was corrected according to the standard. Ignition time and lambda were optimized in order to obtain the best Abstract This work surveyed the combustion behavior of commercial gasoline and hydrous ethanol on a flex-fuel Ford Rocam, four-stroke, four-cylinder, and 1000 cc, spark ignition engine. The crankshaft revolutions were varied and the emissions of oxygen, carbon dioxide, carbon monoxide, and unburned hydrocarbons were acquired. Also the mass fuel flow rate, the cooling fluid temperature, and lambda were measured in order to perform the assessment. Oxygen emissions were used to confirm lambda parameter measurement. Emission index values for carbon monoxide and unburned hydrocarbons were defined in order to compute the combustion efficiency. Nitrous oxides were related to the cooling fluid temperature. As expected, fuel consumption is greater for ethanol than for gasoline. Combustion efficiency which was higher for ethanol and nitrous oxide emissions presented lower values when the engine was operated with gasoline.
A biomassa é a terceira maior fonte de energia para conversão em eletricidade no país, do qual o bagaço da cana-de-açúcar é o insumo energético mais relevante. O bagaço é biomassa residual do processo de moagem industrial, cujo armazenamento faz-se necessário devido à sazonalidade da produção. Os experimentos foram realizados para amostras da estocagem do material em posições distintas (degradação diferenciada), obtido em unidade agroindustrial com 70 mil toneladas adquiridas para utilização em caldeira a vapor. O propósito é avaliar as características físico-químicas (análise imediata, incluindo umidade) e energéticas (poder calorífico) do bagaço da cana-de-açúcar, quando submetido a condições de estocagem a céu aberto durante três anos; com isto, estudar a influência do clima e das condições de armazenamento em alterações do potencial energético desta biomassa residual. Destacam-se os seguintes resultados obtidos: a) Massa específica quatro vezes superior e TUM,BU alcançando 85% quando o bagaço é armazenado a céu aberto; b) Reduzido TCZ (< 1%) possibilitando reduzidos danos e manutenção quando utilizado em caldeiras a vapor; c) Sem degradação significativa para uso como combustível sólido, quanto à TMV,BS e TCF,BS, propiciando respectivamente ignição e estabilidade da combustão, e contribuição significativa no PCS; d) Valores médios para poder calorífico serão consumidos em 15% ou mais no processo de secagem do bagaço; e) A energia térmica disponível (~27 mil TEP) tem significativo potencial para cogeração de energia e aumento no valor agregado da produção agroindustrial.
This paper evaluates internal combustion engine performance parameters (Specific Fuel Consumption and engine torque) and pollutant emissions (O2, CO, and NOX), and also, provide an assessment of economic viability for operation in Amazonas state. Power supply to the communities in the Amazon region has as characteristics high costs for energy generation and low fare. Extractive activities include plenty of oily plant species, with potential use as biofuel for ICE (Diesel cycle) to obtain power generation together with pollutant emission reduction in comparison to fossil fuel. Experimental tests were carried out with five fuel blends (crude palm oil) and diesel, at constant angular speed (2,500 RPM – stationary regime), and four nominal engine loads (0%, 50%, 75%, and 100%) in a test bench dynamometer for an engine-driven generator for electrical-power, 4-Stroke internal combustion engine, Diesel cycle. Main conclusions are: a) SFC and torque are at the same order of magnitude for PO-00 (diesel) and PO-xx at BHP50/75/100%; b) O2 emissions show consistent decreasing behavior as BHP increases, compatible to a rich air-fuel ratio (λ > 1) and, at the same BHP condition, O2 (%) is slightly lower for higher PO-xx content; c) The CO emissions for PO-00 consistently decrease while the BHP increases, as for PO-xx those values present a non-linear behavior; at BHP75%-100_loads, CO emissions are higher for PO-20 and PO-25 in comparison to PO-00; d) The overall trend for NOX emissions is to increase, the higher the BHP; In general, NOx emissions are lower for PO-xx in comparison to PO-00, except for PO-10 which presents slightly higher values than PO-00 for all BHP range; e) Assessment on-trend costs indicates that using palm oil blends for Diesel engine-driven generators in the Amazon region is economically feasible, with an appropriate recommendation for a rated power higher than 800 kW.
A produção de biodiesel no Brasil utiliza mais de 75% da soja como matéria-prima, cujo teor de óleo é ~24%, enquanto que para o crambe alcança ~40%. A torta de crambe (~60% do peso original) é biomassa residual no processo de extração do óleo, que permanece sem destinação comercial adequada visto inadequação como alimento quando in natura. O objetivo é investigar as características energéticas da torta prensada de crambe identificando potencial valorização deste coproduto para conversão em energia térmica. Amostras de crambe após processamento industrial em fábrica de biodiesel foram analisadas quanto à composição química imediata e elementar, bem como massa específica aparente e poder calorífico superior e inferior (PCS e PCI). As principais conclusões obtidas são: PCS de 22 MJ.kg-1 é ~20% superior ao do bagaço da cana-de-açúcar, teor de umidade reduzido e demais parâmetros de qualidade energéticos (TCF, TMV e composição elementar para C, H e O; em oposição ao elevado teor de cinzas, TCZ~6%), indicam características favoráveis ao uso deste coproduto como combustível sólido. A densificação poderia viabilizar o armazenamento, transporte e comercialização da torta de crambe industrial na forma de peletes ou briquetes, visando aplicações com fins de aproveitamento de energia. Assim, identifica-se a torta de crambe com potencial para agregar valor econômico na cadeia produtiva do biodiesel.
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