Process integration, bioethanol

A different approach is provided by the utilization of carbon sources that have a considerable market value and do not constitute waste materials, but are produced in a process integrating the fabrication of the carbon substrate and PHA. This has been implemented on a pilot scale by the company PHB Industrial in the state of Sao Paulo, Brazil. Starting from sugar cane, the company produces saccharose and ethanol. The waste streams from the sugar production (bagasse) and the bioethanol production (fusel alcohols) are used for running the PHA production and making it economically competitive. 

Porzio, G. R, Prussi, M., Chiaramonti, D., Pari, L. Modeling lignocellulosic bioethanol from poplar estimation of the level of process integration, yield and potential for co-prod-ucts. Journal of Cleaner Production 2012, 34,66-75. 

In order to complement this work, purificahon alternatives for bioethanol production should be considered. Also, the effect of the apphcation of process integration techniques on energy and water consumption for the overall process should be analyzed. 

Studies have been conducted on using Kraft paper mills in a biorefinery configuration. The wood material was alkali treated and the cellulose-rich stream obtained can be processed into bioethanol, while the lignin stream can be gassified and refined to get dimethyl ether (Fomell et al., 2013). Further, a system of forest biorefinery integrating a Kraft mill to extract... 

Lindhauer (2005) recently carried out pilot-plant scale trials of an H202-based alkali extraction process, where a product was separated that had a purity of 70-80% arabinoxylans and a yield of 50% of the initial wheat bran. This process is expected to be commercialised as an integrated plant together with bioethanol production. 

High concentrations of ethanol inhibit the fermentation process, ptirticularly when a fermentative medium with high suhstrate concentration is used, as is the case in the majority of the industrial processes. Considering this, Silva et al. [1] studied a process of fermentation combined with a flash vessel, which selectively extracts ethanol firom the medium as soon as it is produced. These authors have shown that this scheme presents many positive features and better performance than conventional industrial processes [2]. Cardona and Sanchez [3] point out that the reaction-separation integration is a particularly attractive alternative for the intensification of bioethanol production. When bioethanol is removed fiom the culture broth, its inhibition effect on the growth rate is diminished or neutralized. However, the performance of the whole process is significantly influenced by separation unit, and that means that thermod)mamic knowledge of the mixture is required. 

Macrelli S, Mogensen J, Zacchi G. (2012). Techno-economic evaluation of 2nd generation bioethanol production from sugar cane bagasse and leaves integrated with the sugar-based ethanol process. Biotechnol Biof, 5, 22. 

Scheme of production of bioethanol from scotta with MBR, for example integrated fermenter and membrane processes. 

Dias, M., A. Ensinas, S. Nebra, R. Maciel, C. Rossell and M. Wolf (2009a). Production of bioethanol and other bio-based materials from sugarcane bagasse Integration to conventional bioethanol production process. Chemical Engineering Research and Design 87 1206-1216. 

Morales-Rodriguez, R., A. S. Meyer, K. V. Gemaey and G. Sin (2011b). Dynamic model-based evaluation of process configurations for integrated operation of hydrolysis and co-fermentation for bioethanol production from lignocellulose. Bioresource Technology 102(2) 1174-1184. 

A biorefinery design that aims to make optimal use of available streams to minimise inputs and emissions will form mass exchange networks. Highly integrated biorefineries will not only exchange intermediate streams but also product streams that can be used as in-process raw materials such as CO, hydrogen or bioethanol (Martinez-Hemandez et al. 2013). CO ... 

Martinez-Hemandez, E., Sadhnkhan, J. and Campbell, G.M. (2013) Integration of bioethanol as an in-process material in biorefineries nsing mass pinch analysis. Appl. Energy, 104, 517-526. 

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