Category Archives: PROCESS SYNTHESIS. FOR FUEL ETHANOL. PRODUCTION

Evolutionary Modification

Evolutionary modification is the conventional approach for process synthesis based on the experience of engineers and researchers. This approach condenses this experience into a programmed set of heuristic rules intended to making deci­sions on the process structure. Considering that this method corresponds to a trial — and-error approximation, its main limitation consists in the difficulty of obtaining relevant information in […]

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PRETREATMENT OF STARCHY MATERIALS

When cereals are used for producing fuel ethanol, the feedstock enters the pro­cess in the form of grains, which need to undergo some preliminary operations like washing and milling. As pointed out in Chapter 3, the milling of cereal grains like corn, wheat, and barley can be carried out by either the wet-milling or dry­milling process. In wet-milling technology only […]

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Semicontinuous Fermentation

Fed-batch fermentation is one of the most employed cultivation regimes when process microorganisms present catabolic repression, i. e., when high substrate concentrations inhibit specific metabolic processes like those related to cell growth rate. For this reason, the microorganisms grow faster at low substrate concentrations. In fact, the cultivation of S. cerevisiae to produce baker’s yeasts is accomplished by this process. […]

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Case Study. Modeling of SSF of Biomass in Batch and Continuous Regime

The importance of modeling SSF processes is invaluable considering the design of fuel ethanol production processes employing lignocellulosic materials as feedstocks. In a previous work (Sanchez et al., 2005), the analysis of SSF for conversion of cellulose into ethanol was performed in both batch and continu­ous regimes. The kinetic model of such a process was based on the mathemati­cal description […]

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Simulation of Fuel Ethanol Production from Corn by SSF and Comparison to Sugarcane-Based Process

As mentioned in Case Study 11.1, the aim of simulating the process to obtain bio­ethanol from dry-milled corn can provide valuable information on the suitability of different technological configurations, in this case, the configuration involving the SSF of the starch contained in the corn grain. This simulation was performed in previous works (Cardona et al. 2005b; Quintero et al. 2008) […]

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Preface

The mitigation of climate change, energy versus food security, and equity in rural areas are some of the main global goals facing the world today. One of the real options to achieving these goals is the development of cleaner and renewable energy sources, such as biofuels. Fuel ethanol from sugarcane and corn is world­wide the most important biofuel, followed by […]

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Hydrolysis of Carbohydrate Polymers

The hydrolysis of glucans is a significant source of fermentable sugars for fuel ethanol production. The most important glucans in ethanol industry are starch and cellulose. In this chapter, the features of starch and cellulose hydrolyses are discussed. In particular, the difficulties related to the enzymatic hydrolysis of cellulose are analyzed taking into consideration the enzyme complexes used and the […]

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DYNAMICS OF CONTINUOUS FERMENTATION SYSTEMS

Besides design procedures, process systems engineering applied to fuel ethanol production processes consists of operation and control, especially when differ­ent technologies are to be implemented at industrial level. This is particularly important for continuous ethanologenic fermentation. If such a system is operated under conditions corresponding to a stable steady state, any small perturbation in input parameters (like dilution rate, temperature, […]

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SEPARATION-SEPARATION INTEGRATION FOR BIOETHANOL PRODUCTION

The development of technologies for separation-separation integration has been linked to the development of the different unit operations involved during down­stream processes and to new approaches for process intensification. The examples of separation-separation integration in the case of ethanol production mostly cor­respond to integration of the conjugated type, i. e., when integrated processes are carried out in different equipments closing […]

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