Effects of water content on the solubility between Isopropanol-Butanol-Ethanol (IBE) and diesel fuel under various ambient temperatures

Isopropanol/n-butanol/ethanol (IBE) is an intermediate product of microbial fermentation during n-butanol production. It not only retains many advantages of oxygenated fuel, but also reduces the high cost of n-butanol production. IBE production carries some water during fermentation process. If water-containing IBE can be mixed with diesel to prepare diesel microemulsions for use, it will reduce the energy consumption of water removal. Therefore, a series of experimental evaluations of the IBE-diesel mixture with or without water were conducted to study the miscibility of IBE and diesel, furthermore, the potential of preparing diesel microemulsion and the characteristics of the diesel microemulsion were also analyzed in this paper. Results show that the mixture of IBE and diesel is transparent and stable single-phase liquids at experimental temperatures as without water addition. As temperature increases, water content in the IBE-diesel system that does not cause stratification increases gradually. When increased the right amount of water to IBE-diesel system, it maintained a transparent and stable single-phase liquid, and distribution of the particle size was about between 3 and 53 nm. Among all the different volume ratios of IBE mixtures, IBE (3: 6: 1) shows the greatest water tolerance and the best oil-water balance ability, followed by IBE (6: 3: 1) and IBE (1: 1: 1). Simultaneously, the particle size of the IBE (3: 6: 1) ternary system is also relatively small, so it had better stability. Therefore, the diesel microemulsion prepared by IBE (3: 6: 1) as a new compound fuel should be well applied to diesel engines.