Energy and Water Optimization in Biofuel Plants

Abstract

In this paper we address the topic of energy and water optimization in the production of bioethanol from corn and switchgrass. We show that in order for these manufacturing processes to be attractive, there is a need to go beyond traditional heat integration and water recycling techniques. Thus, we propose a strategy based on mathematical programming techniques to model and optimize the structure of the processes, and perform heat integration including the use of multi-effect distillation columns and integrated water networks to show that the energy efficiency and water consumption in bioethanol plants can be significantly improved.Specifically, under some circumstances energy can even be produced and the water consumption can be reduced below the values required for the production of gasoline.

The role of water in catalytic biomass-based technologies to produce chemicals and fuels

“…Water requirements of the production process could be decreased by energy integration and water optimization including water recycling and zero discharge. By this optimization method the water consumption should be 2.85 L of water per 1 L of ethanol [81]. The application of dry mill technologies further decreased the water demand [80].…”

A Review of Life Cycle of Ethanol Produced from Biosyngas

“…2). The overall stoichiometric reaction for alcohol synthesis is summarized in the following equation Unauthenticated Download Date | 5/11/18 11:52 AM energy or even produces it [58,59] because of the implementation of multieffect columns followed by heat integration (hot and cold streams) in the process. MINLP approach is also used to evaluate the LC (cradle to grave) of ethanol from wood chips considering the environmental and social criteria.…”

“…The growing concern about sustainability of ethanol produced The thermochemical process noted to have negative net fossil fuel consumption, consequently negative net GHG emissions [57,58] if plant is designed as energy self-sustained and no mixed alcohol separation unit installed (i.e., some biosyngas is diverted for heat and electricity generation). The co-product credit (mainly from electricity export) offsets the energy consumption and GHG emissions in the LC of ethanol.…”

“…The ethanol production processes were modeled with the mixed-integer nonlinear programming (MINLP) and implemented in the GAMS modeling system to optimize the systems [58,59]. Ethanol yield was reported to be greater in low pressure gasification process than that of high pressure thus reduce production cost.…”

“…The estimated production cost is noted to be 0.55-0.59 $/L. The estimated production cost of ethanol produced by optimized thermochemical conversion process is reported to be 0.11-0.25$/L due to the large contribution of coproduct (hydrogen) [58,59]. The production cost is reported to be greater for gasification-fermentation route compared with gasificationcatalytic synthesis [79].…”