Bioalcohol production process

As introduced in the previous section, many types of lignocellulosic biomass have been used for producing bioalcohols. Feasibility of the processes for different feedstocks is therefore a function of the biomass, of which the treatment conditions and processes are specific to the raw materials. Availability in bulk at low cost, ease of processing, and bioalcohol yield are the key parameters that affect the choice of selection. Some of the key biomasses used for bioalcohol production and their potential yield are listed in Table 9.2. 

Similarly to biobutanol, biopropanol is another bioalcohol with high heating value. Isopropanol can be dehydrated to produce propylene, a product that can be used to esterify fats and oils for the production of biodiesel. Isopropanol can be produced by Clostridium or genetically modihed E. coli. Commercial isopropanol production from biomass-derived glucose is highly desired (Ismaiel et ah, 1993). However, the highest concentration of biopropanol observed from fermentation experiments was 4.9 g/L (Atsumi and Liao, 2008), which is still much lower than the titer of the bioethanol production process. More research would be expected to increase the efficiency and yield of the process before sizable application. 

Recent studies have demonstrated the use of oleic acid as an efficient substrate for production of biodiesel by esterification using lipase. Mulalee et al. (2013) studied the production of biodiesel from oleic acid and bioalcohols (ethanol and butanol) using immobilized lipase (Novozym 435) as biocatalyst in a batch esterification process. The optimal conditions were 45 C, oleic acid to alcohol molar ratio of 1 2, Novozym 435 loading at 5% based on oleic acid weight and 250 rpm, in which the free fatty acid conversion at 91.0% was obtained after 12 hours of the reaction. 

Biomass can be converted into biofuels via two main types of processes thermochemical and biochemical/biological conversion (Huang and Yuan, 2015). The typical products of the thermochemical conversion process include syngas, bio-oil, and biochar and the products of the biochemical conversion process are bioalcohols, carbohydrates, and lignin. Our concern in this chapter is biochemical production of bioalcohols, or biorefinery process through the well-known sugar platform. ... 

The bioalchols, such as bioethanol, biobutanol or bioglycerol can be converted to oxygenates fuel additives, acetals. The synthesis of acetal takes place by reacting one of these alcohols with and aldehyde, for example, n-butyraldehyde. Nowadays, aldehydes production takes place through hydroformylation reaction of alkenes, but other process such as bioalcohols oxidation can also be employed to produce aldehydes. Due to the origin of these bioalcohols, the production of the aldehydes by this new process is very attractive, therefore the butanol oxidation to butyraldehyde may be a way more consistent with the current environmental policies. 

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