Distillation, bioethanol production

Bioethanol with the lowest cost is obtained by the evaporation through the membrane independently of the type of raw material for processing. Thus, when the bioethanol production from the sugar beet (cmde juice) by the azeotropic distillation was used, the production cost of 1 ton of bioethanol was USD 1447.5 ( 1.14 per 1 L), and when the evaporation through the membrane was used - 1378.2 ( 1.09 per 1 L) or decreased by 4.8%. 

The analogical dependence occurred when the bioethanol production from green blackstrap molasses, symp and molasses took place. The lowest production cost of bioethanol from molasses was obtained while using all three processing technologies. Thus, the production of bioethanol from the molasses by azeotropic distillation the production cost of 1 ton of bioethanol was 934.7 ( 0.74 per 1 L), and it decreased by 7.4% - to 865.5/t ( 0.69 per 11) when the evaporation through the membrane was used. 

Saccharomyces cerevisiae is the dominant microorganism in the first generation of fuel ethanol production. In recent years, the worldwide bioethanol production reached around 80 billion liters per year. In a typical industrial scale bioethanol fermentation process using Saccharomyces cerevisiae, around 8-14% (v/v) ethanol is produced and the glucose to bioethanol yield is usually over 90% of the theoretical yield. In some processes, simultaneous saccharification and fermentation is applied, in which a-amylase/glucoa-mylase is mixed with Saccharomyces cerevisiae and starchy raw materials. Most of yeast cells harvested in the fermentation are recycled and sent back in order to enhance the cell concentration in the fermenter. Around 5-10% yeast cells end up in Dried Distillers Grains with Solubles (DDGS), which could be sold as animal feed. 

There are some obvious advantages of isobutene fermentation compared to liquid fuels. For example, in bioethanol production, distillation accounts for about 9 % of its total cost and 58 % of the total energy use at an ethanol plant, and distillation of 1-butanol would be more expensive due to its higher heat of vaporisation and presence of other solvents that need to be fractioned (Rude and Schirmer 2009 Gogerty and Bobik 2010). On the other hand, since isobutene is a gaseous substance practically insoluble in an aqueous fermentation broth, it can easily be recovered from the bioreactor (van Leeuwen et al. 2012 Martin and Grossmann 2014). 

Junqueira, T. L., M. O. S. Dias, R. M. Filho, M. R. W. Maciel and C. E. V. Rossell (2009). Simulation of the azeotropic distillation for anhydrous bioethanol production study on the formation of a second liquid phase. Computer Aided Chemical Engineering 27 1143-1148. 

Dias, M.O.S., Modesto, M., Ensinas, A.V., Nebra, S.A., Filho, R.M., Rossell, C.E.V., 2011. improving bioethanol production from sugarcane evaluation of distillation, thermal integration and cogeneration systems. Energy 36 (6), 3691-3703. 

BioSep" novel membrane distillation processes for bioethanol production (February 2009). www.mtrinc.com/news. html. 

Bioethanol is the largest biofuel today and is used in low 5%—10% blends with gasoline (E5, E10), but also as E85 in flexible-fuel vehicles. Conventional production is a well known process, based on the enzymatic conversion of starchy biomass (cereals) into sugars, and fermentation of 6-carbon sugars with final distillation of ethanol to fuel grade. 

The overall production process for bioethanol has a clear advantage over some other industrial fermentation products. Due to the fact that all the input streams are converted to products such as bioethanol, gluten or a protein-rich feed stuff, so-called DDGS (distillers dried grains with solubles), fertilizer and a readily biodegradable wastewater the process can be seen as a zero-waste-concept. 

The combirration of distillation and merrrbrane separation cart, for instance, be applied to processes for the production of bioethanol. In the process preserrted in Fig. 11.4-7 (Weyd et al. 2010) the azeotropic overhead fraction of column C-1 is... 

Bioethanol is an aqueous solution containing between 8.0 and 12.0 wt% of ethanol and some by-products depending on the raw material used [124]. Nevertheless, the bioethanol distillation is an expensive process, because of the azeotrope presence. For this reason, in the last years, bioethanol is directly used as fuel in steam reforming reaction. Moreover, an excess of water improves the paUadium-based MR performances reducing also the CO content as by-products. 

The integration of biopolymer production into an existing sugar cane mill has been realized on a pilot scale by the company PHBISA in Brazil, where the saccharose obtained is converted to bioethanol and partly to PHA. In this scenario, the energy required for bioethanol and biopolymer production is generated by burning surplus biomass, namely bagasse. The fusel oil fraction of the bioethanol distillation is applied as an extraction solvent for PHA isolation from microbial biomass (Nonato et al. 2001). 

The reduction of the bioethanol cost and the increase of its competitiveness depend greatly on the production technology. Bioethanol technology consists of two phases the prodirction of raw ethanol and its further del dration. Azeotropic distillation, adsorption on molecular sieves and evaporation through the membrane are rrsed for ethanol delydration of [8]. 

Many variations exist of pyrolysis-based biorefineries, and an early (1920s) example is the production of charcoal and various other products in the continuous wood distillation plant of the Ford Motor Company in Michigan, USA. This plant used 400 tons per day of scrap wood from the automobile body plant.The Ford plant not only produced make acetic acid (among charcoal and other products) but also ethyl acetate (via esterification with bioethanol), which the company required in its lacquer and artificial leather departments. The first T-Fords used bioethanol as their transportation fuel. Figure 8.2 gives a schematic overview of the plant that was completely self-sufficient with regard to its heat demand. 

Ethanol isolation proceeds via distUlative processes. Owing to the formation of an ethanol/water azeotrope (95.5 mass% ethanol at 1 bar), the production of water-free ethanol requires the application of extractive distillation (typical entrainer benzene or cyclohexane, see Section 3.3.2.3). The isolation of water-free ethanol from fermentation is a relatively energy intense step. Even with a clever combination of several distillation columns working at different pressures, the energy input to produce 1 kg of bioethanol by fermentation is about 10 MJ (Baerns et al, 2006). In a few countries, where the production of bioethanol is particularly cheap (e.g., Brazil), there have also been attempts to convert bioethanol into chemicals in commercial scenarios. The production of ethylene from bioethanol is a potential option in this context. 

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