Integrated processing for the separation of biobutanol. Part A: experimental investigation and process modelling

Abstract

n -Butanol is an important bulk chemical and a promising potential fuel additive. An alternative way to the chemical production of biobutanol from crude oil is the fermentation of biomass. However, the main drawback of this process is the toxicity of n -butanol towards the microorganisms resulting in a limited productivity. Additionally, high purification costs occur due to an energy-intensive distillation step which is used, up to now, as purification technology for the recovery of n -butanol. Therefore, alternative separation processes are discussed in this study. Extraction and pervaporation are two unit operations with high potential to overcome this problem. Because of their tuneable properties, the use of ionic liquids as extraction solvents for n -butanol recovery is a promising option; however, their economic potential is not obvious because of the relatively high costs. On the basis of those two unit operations, different potential processes to separate biobutanol from water are modelled using experimental data. Cost estimations result in purification costs of € 0.230 kg -1 to € 0.296 kg -1 n -butanol, which accounts for 20% -27% of the n -butanol market price in 2012.

Quest for sustainable bio-production and recovery of butanol as a promising solution to fossil fuel

“…It has been defined as the most economical recovery process for alcohol from aqueous streams [128]. It has been defined as the most economical recovery process for alcohol from aqueous streams [128].…”

“…Because of their properties (i.e. non-toxic, nonvolatile, non-flammable, hydrophobic and thermally stable), several authors have proposed ILs as promising substitutes for traditional liquid-liquid biobutanol extraction solvents [128]. Additionally, ILs have been studied as potential solvents for different bio-catalytic applications including volatile organic compounds biodegradation, trans-esterification or lactic acid extraction [127,129,130].…”

“…Pervaporation is a potential process for recovering biobutanol from biomass fermentation broth with the aid of a membrane. It has been defined as the most economical recovery process for alcohol from aqueous streams [128]. Pervaporation allows the selective removal of desired volatile compounds from the liquid mixture combining evaporation and membrane permeation [164].…”

“…Nevertheless, this value was significantly smaller in comparison with the 18.4 MJ/kg-BuOH required for simple distillation without extractant. Stoffers et al (2013) determined a 5% saving in crude oilbased n-butanol market price (€1.11/kg in 2012) when an integrated extraction-distillation process employing IL as extraction solvent was installed instead of a distillation process employing two columns and a decanter [128]. Matsumura et al (1988) proposed a hybrid pervaporationdistillation system with an oleyl alcohol liquid membrane for butanol-water separation [109].…”

Optimal design of an efficient, profitable and sustainable biorefinery producing acetone, butanol and ethanol: Influence of the in-situ separation on the purification structure

“…We emphasize that the superstructure comprises also a scenario without separation and the scenarios with the new technologies for the butanol recovery. Moreover, Stoffers et al [24] modeled several alternatives of separations for the purification of only the biobutanol and compared them in function of the purification cost of biobutanol. They proved that the extraction alternative presents lower purification cost than pure distillation alternative.…”