Study of droplet vaporization of various vegetable oils and blends of domestic fuel oil–cottonseed oil under different ambient temperature conditions

In this work, the evaporation characteristics of different pure vegetable oils (cottonseed oil, jatropha oil, and rapeseed oil), domestic fuel oil (DFO) and blends of domestic fuel oil and cottonseed oil have been studied using the fibre-suspended droplet evaporation technique. The constants of evaporation of pure products were determined as well as the influence of the proportion of DFO fraction on the mechanisms of vaporization process of cottonseed oil in the temperature range of 578 K–917 K under atmospheric pressure. The results show that the DFO evaporates completely in the range of temperatures considered in contrast to vegetable oils that vaporize completely only for temperatures higher than or equal to 773 K. Above 873 K, the behaviour of vegetable oils becomes similar to a single component product and the d2 law is respected. At a given temperatures range, constants of evaporation of the three vegetable oils are of the same order of magnitude. The results also show that blends of cottonseed oil and DFO vaporize following a sequential distillation mechanism: DFO is evaporating first, followed by a transient phase, and then cottonseed oil vaporizes following the same trends than observed for pure vegetable oils. For low percentages of cottonseed oil (≤40%) in the mixture, formation of bubbles can be observed at the end of the process at 684 K. When the concentration of vegetable oil in the droplet increases, the mechanism of pure diffusion becomes predominant.

► Studied vegetable oils vaporize completely for temperatures higher than 773 K.
► Blends of cottonseed oil and DFO vaporize following a sequential distillation mechanism.
► For low percentages of cottonseed oil formation of bubbles is observed at 684 K.
►  Internal recirculation progresses toward diffusion when vaporization is progressing.