Deposit formation in aero engines—investigation by pressure differential scanning calorimetry (PDSC)

Avaliação da estabilidade oxidativa de biodiesel de óleo de girassol com antioxidantes

“…26 Técnicas automáticas incluem medida da estabilidade do óleo (OSI), Teste em Rancimat ® e análise termogravimétrica (TGA). 27 Técnicas analíticas térmicas, tais como TGA, equipamentos de calorimetria diferencial convencional (DSC) e pressurizado (P-DSC), têm sido aplicadas em análises de oxidação de derivados de petróleo e lubrificantes sintéticos, 28 lubrificantes biodegradáveis, 29 óleo de turbina de avião e polímeros, 30,31 bem como resinas de madeira. Estes estudos geralmente mostram que a P-DSC tem a vantagem de aumentar o número total de moles de oxigênio presente na célula, permitindo a aceleração da reação a baixas temperaturas.…”

Behavior of High Temperature Lubricants in a Pressure Differential Scanning Calorimeter

“…Since no deposits were observed at the end of the run, the data show that the two overlapping sets of exotherms observed in the thermograms of the polyphenylethers are due to oxidation of the lubricant followed by oxidation of the formed deposit to volatile species. Mineral oils (7) and esters (9) have also been reported to produce separate oxidation exotherms and deposit oxidation exotherms. For these lubricants, the exotherms are well separated due to the relatively poor oxidative stability of these types of lubricants.…”

“…This technique has been used to separate simultaneously occurring events at atmospheric pressure such as oxidation (exothermic) and volatilization (endothermic). Even more recently, a hermetically sealed pan with a small hole in the lid has been used in conjunction with PDSC (7)- (9). The controlled diffusion of the hole even more greatly restricts the volatilization of the lubricant while still allowing for saturation of the liquid phase with oxygen.…”

“…Behavior of High Temperature Lubricants in a Pressure Differential Scanning Calorimeter 587 restricted diffusion PDSC was determined under experimentally similar conditions but was not correlated with engine test results (9). PDSC has not been extensively applied to the lubricant classes that possess superior oxidative stability such as polyphenylethers, perfluoroalkylethers, polyphenylthioethers and substituted cyclophosphazenes.…”

Fuel Properties and Performance of Biodiesel

“…P -DSC has the added advantage of providing elevated pressures which increases the total number of moles of oxygen available for reaction. These techniques have been applied to the analysis of petrochemical and synthetic lubricants, biodegradable lubricants, aviation turbine oils and polymers (Sharma and Stipanovic, 2003 ;Gamelin et al , 2002 ;Riga et al , 1998 ;Yao, 1997 ;Zeman et al , 1995 ;Patterson and Riga, 1993 ;Zeman et al , 1993 ;Kaufman and Rhine, 1988 ;Zeman et al , 1984 ;Walker and Tsang, 1980 ;Noel, 1972 ) as well as edible fats and oils, air -blown vegetable oils, epoxidized soybean oil, genetically modifi ed soybean oil and alcohol -based fuels (Adhvaryu and Erhan, 2002 ;Kenar et al , 2002 ;Tan et al , 2002 ;Adhvaryu et al , 2000 ;Kowalski et al , 2000 ;Perez, 2000 ;Litwinienko and Kasprzycka -Guttman, 1998 ;Litwinienko et al , 1995 ;Kasprzycka -Guttman et al , 1995 ;Kowalski, 1995 ;Hassel, 1976 ;Cross, 1970 ).…”