Fillat U.,Polytechnic University of Catalonia |
Roncero M.B.,Polytechnic University of Catalonia |
Bassa A.,Fibria Technology Center |
Sacon V.M.,Brazil Technology Center
Tappi Journal | Year: 2012
In this study, we examined the effect of treating eucalyptus pulp with various commercial xylanases to identify the most effective enzyme for use under the industrial bleaching conditions used at the Jacarel mill of the Brazilian firm Fibria, which include a high pH and temperature. Based on the results, the use of two of the nine enzymes studied reduced the kappa number by 1.5 units, increased brightness by 2.5% ISO, and decreased hexenuronic acids (HexA) content by more than 10 pmol/g relative to a control treatment in the absence of enzyme. The most marked changes in brightness were observed on application of an oxidative D stage to enzyme-treated pulp samples. Finally, the chemical oxygen demand (COD), total organic carbon (TOC), color, and turbidity of the effluents obtained at the end of the processes involving the enzymes were all higher than in the control process.
Ferrarese A.,Brazil Technology Center |
Marques G.,Brazil Technology Center |
Tomanik E.,Brazil Technology Center |
Bruno R.,Brazil Technology Center |
Vatavuk J.,Mackenzie Presbyterian University
SAE International Journal of Engines | Year: 2010
With the current use of bio-renewable fuel, the application of Ethanol in Flex-Fuel vehicles presents a very low CO2 emission alternative when the complete cycle, from plantation, fuel production, till vehicle use, is considered. In Brazil more than 80% of the car production is composed of Flex-Fuel vehicles. Due to the lower heating content of the Ethanol, more aggressive combustion calibrations are used to obtain the same engine power than when burning gasoline. Such Ethanol demands, associated with the continuous increase of engine specific power has lead to thermomechanical loads which challenges the tribology of piston rings. The ethanol use brings also some specific tribological differences not very well understood like fuel dilution in the lube oil, especially on cold start, corrosive environment etc. Under specific driving conditions, incipient failures like spalling on nitrided steel top rings have been observed. When running with Ethanol, Flex-Fuel engines present higher PCP and this peak occurs in a crank angle closer to the Top Dead Center. Such condition increases ring wear, scuffing risk and tribological conditions that may lead to cracks on the nitrided case and later spalling. This paper covers the top ring performance on flex-fuel engines on the tribology perspective. It is discussed how the ethanol use on Flex-fueled engines affects the top ring in terms of wear, scuffing, spalling and friction. For the evaluation of wear and spalling resistance, dyno engine tests are presented. On scuffing, block on ring tests were performed and a rank of ring coatings is presented. Top ring friction behavior and its impact on fuel consumption are also discussed. Test results on engine floating liner are presented. Finally, ring technical solutions to overcome these challenges are discussed. Among them, steel piston ring with an improved nitriding treatment for increased toughness and a PVD coating to improve wear resistance and friction. It is presented several rig and engine tests to support the discussed technical solutions. Engine tests are based on an abusive procedure to evidence/anticipate the effects on performance caused by the unique characteristics of flexfueled engines running with Ethanol. © 2010 SAE International.
Cordeiro S.M.,Brazil Technology Center |
Yoshino F.J.,Brazil Technology Center
SAE Technical Papers | Year: 2011
At flex fuel technology introduction in the Brazilian market, new technical issues came-up due to ethanol chemical reaction with component materials developed only for gasoline aging. One of these items was the gel formation at fuel system. This gel flows through the fuel systems and clogs the fuel filters. And, as final result, the fuel pump is lost due to overpressure working condition. To implement solutions against this way of failure, it was necessary to understand gel formation mechanism in laboratory level. In this investigation, many boundary conditions were changed and analyzed in order to identify contribution of each factor during gel formation process. As result, it was possible to implement a laboratory gel formation test for fuel filters, not depending any more from field tests and allowing test repeatability to develop an improved fuel filter. Copyright © 2011 SAE International.
Yoshino F.J.,Brazil Technology Center |
Marques G.A.,Brazil Technology Center |
Fritz L.C.,Brazil Technology Center |
De Aquiar B.,Brazil Technology Center |
Moreira F.,Brazil Technology Center
SAE Technical Papers | Year: 2011
The flex-fuel engine technology evolution and bio fuels increasingly market presence brings new challenges on components development requirements. One of the affected products is the fuel filter, where downsizing, dust holding capacity and filtration efficiency are the improvement goals. In order to attend these market demands, MAHLE has developed a new flex-fuel filter generation. This new product is able to double the dust holding capacity while maintaining the filtration efficiency. In addition, new product dimensions, like body diameter and distance between inlet and outlet, are the same found in current solutions. In this way, it can be used in many vehicles with none or few modifications at interface components. First optimization was done through changes in filter housing design and fuel system line connectors. Second optimization was single layer cellulose media improvement to multilayer concept. Comparative tests between this new flex-fuel filter generation and current solution was done to confirm performance improvement. Copyright © 2011 SAE International.