Strategies to Introduce n-Butanol in Gasoline Blends

Abstract

Abstract:The use of oxygenated fuels in spark ignition engines (SIEs) has gained increasing attention in the last few years, especially when coming from renewable sources, due to the shortage of fossil fuels and global warming concern. Currently, the main substitute of gasoline is ethanol, which helps to reduce CO and HC emissions but presents a series of drawbacks such as a low heating value and a high hygroscopic tendency, which cause higher fuel consumption and corrosion problems, respectively. This paper shows the most relevant properties when replacing ethanol by renewable n-butanol, which presents a higher heating value and a lower hygroscopic tendency compared to the former. The test matrix carried out for this experimental study includes, on the one hand, ethanol substitution by n-butanol in commercial blends and, on the other hand, either ethanol or gasoline substitution by n-butanol in E85 blends (85% ethanol-15% gasoline by volume). The results show that the substitution of n-butanol by ethanol presents a series of benefits such as a higher heating value and a greater interchangeability with gasoline compared to ethanol, which makes n-butanol a promising fuel for SIEs in commercial blends. However, the use of n-butanol in E85 blends substituting either gasoline or ethanol may cause cold-start problems due to the lower vapor pressure of n-butanol. For this reason, a combined substitution of n-butanol by both gasoline and ethanol is proposed so that n-butanol can be used without start problems.

Physicochemical Properties of Biobutanol as an Advanced Biofuel

“…[ 81 , 82 ]. Corrubia et al, 2020 [ 83 ], Da Silva et al, 2005 [ 79 ], or Lapuerta et al, 2017 [ 84 ] measured the research octane number for ethanol, n-butanol, and i-butanol. The results of our research complement the results of these authors by analyzing mixtures while using gasoline from Central Europe.…”

Production and Use of Sustainable C2‐C4 Alcohols – An Industrial Perspective

“…Butanol is less corrosive than ethanol and it has a higher lubricity. Moreover, butanol has a better miscibility with gasoline and is more compatible with the existing gasoline infrastructure , . With butanols, the decrease in emissions of CO, hydrocarbons and particulate matter as well as the increase in carbonyl emissions are similar to those with the use of ethanol.…”

“…On the other hand, the octane numbers of butanol are lower than those of ethanol and the viscosity and the density are higher. Cold‐start problems can be caused by the lower vapor pressures of butanol compared to ethanol . However, the main disadvantage of n ‐butanol and isobutanol is that there is a lack of sustainable and economic processes, which is also problematic for a wider use of propanols as fuel components.…”

“…Oxygen within the ethanol molecule can provide a more homogenous fuel‐air‐mix, resulting in lower emissions of unburned or partially unburned molecules (hydrocarbons and CO) . Lower emissions of particulate matter and NOx are also described when ethanol is blended to gasoline , . The disadvantages of ethanol as a fuel include a significantly lower energy density as well as its corrosiveness, its low flame luminosity, its miscibility with water, its hygroscopic behavior, its tendency to form azeotropes with lighter hydrocarbons, its lower vapor pressure and emissions of acetaldehyde , .…”

Genetic engineering of non-native hosts for 1-butanol production and its challenges: a review

“…Compared to ethanol, butanol has superior physical and chemical properties, such as higher energy density (27 MJ/L vs. 19.6 MJ/L), low water miscibility, low flammability, lesser corrosiveness, and closely resembles to modern-day gasoline (Table 1). Further, butanol can be blended with gasoline in any ratio and used directly in automobile engines without structural modification, besides being transported through the existing pipeline infrastructure [2,3]. Butanol also has several applications in various chemical industries.…”