Projeto, construção e testes de um trocador de calor visando a refrigeração de uma turbina de um motor ottolizado para gás natural

Abstract

The use of electric power has become increasingly costly for companies, especially for the large ones, at times of high demand (18 to 21 h). Substituting the purchase of electric power from the concessionaires for the independent production of electric power, with generator sets, has attracted the attention in part of these companies Currently, most of the engines of these generator sets are diesel powered. However, replacing diesel with natural gas in these engines is an interesting opportunity to reduce fuel costs. The Innovation Laboratory of the Federal University of Paraíba has developed an innovative, fully reversible technique capable to convert diesel engines to operate with natural gas only (ottolization). A major problem caused by the use of natural gas is the high temperatures of the exhaust gases, especially in turbocharged engines. These high temperature values can permanently damage the turbocharger. The aim of this work was the design, construction and assembly of a heat exchanger for the cooling of the exhaust gases and the analysis of the influence of its cooling in the operation of the turbocharged Perkins 1104-44TAG2 engine. The type of heat exchanger constructed was finned tubes. In the tests performed, the maximum power reached within the exhaust gas temperature limit at the turbocharger output, 600 ºC, was 80.9 kW (110 cv). At 110 cv, the fuel consumption was reduced about 3.5 % in relation to the data of the reference works. The thermal efficiency of the engine in this same power was 42.76 % and the effectiveness of the heat exchanger was 49.2 %.