Non-catalytic thermal decomposition of naphthenic acids of petroleum crudes

The thermal decomposition of naphthenic acids was carried out in a 50 mL glass vessel equipped with a bottom sparger (for bubbling a gas: H-2, N-2, steam) and a removable head cap for charging the oil and also containing the gas outlet connections. Gas at a suitable flowrate (1.5-4.5 mL min(-1)) was used for stripping the decomposition products formed at different heating temperatures (360, 380, 400 degrees C). Results show that the thermal decomposition of naphthenic acids follows a second order kinetic model. Three carrier gases were tested, nitrogen, hydrogen and steam. The gases stripped the fluid phase from the produced dioxide carbon. Best results were obtained when using nitrogen as stripping gas, at 400 degrees C and 1.5 L h(-1) stripping rate. A 90% decrease of acidity was achieved with a treatment of 4 h. This final TAN value is considered acceptable for a subsequent refining of the crude in a common refinery. [GRAPHICS] .