High Temperature Thermal Stability Investigation of Paraffinic Oil

The physical and thermal properties of paraffinic oil were investigated at 250-360°C to determine its suitability for use as a heat-transfer fluid. Thermal stability test was conducted at 360°C for a period of 480 hr in a stainless steel high-pressure autoclave. The paraffinic oil offered sufficient thermal stability for a period of about 300 hr and then became unstable resulting in thermal break down or cracking of the oil. Degradation of the oil led to the formation of gases, liquid components, and solid coke of about 5 wt.% of the starting material. The distillation test performed on the liquid components showed that the composition varied from light naphtha to heavy bituminous material.

The paraffinic oil compared favorably with synthetic organic fluids and the typical properties revealed its suitability as a heating fluid in a system with maximum usage temperature of 310°C as indicated by the thermal stability test. Comparative evaluation of the general properties of the tested paraffinic oil with other paraffinic and mineral oils of different product formulations showed excellent agreement. From these results, it is concluded that the paraffin oil sample produced by the local refinery is suitable for use as a potential thermal fluid at temperatures below 315°C, which is quite adequate for many industrial applications.