Simultaneous Optimization and Integration of Multiple Process Heat Cascade and Site Utility Selection for the Design of a New Generation of Sugarcane Biorefinery.

Biorefinery plays a crucial role in the decarbonization of the current economic model, but its high investments and costs make its products less competitive. Identifying the best technological route to maximize operational synergies is crucial for its viability. This study presents a new superstructure model based on mixed integer linear programming to identify an ideal biorefinery configuration. The proposed formulation considers the selection and process scale adjustment, utility selection, and heat integration by heat cascade integration from different processes. The formulation is tested by a study where the impact of new technologies on energy efficiency and the total annualized cost of a sugarcane biorefinery is evaluated. As a result, the energy efficiency of biorefinery increased from 50.25% to 74.5% with methanol production through bagasse gasification, mainly due to its high heat availability that can be transferred to the distillery, which made it possible to shift the bagasse flow from the cogeneration to gasification process. Additionally, the production of DME yields outcomes comparable to methanol production. However, CO2 hydrogenation negatively impacts profitability and energy efficiency due to the significant consumption and electricity cost. Nonetheless, it is advantageous for surface power density as it increases biofuel production without expanding the biomass area.

Optimization of a biotechnological multiproduct batch plant design for the manufacture of four different products: A real case scenario.

In this work a biotechnological multiproduct batch plant that manufactures four different recombinant proteins for human application is described in some detail. This batch plant design is then optimized with regards to the size of equipment using a mixed-integer linear programming (MILP) formulation recently developed by us in order to find a hypothetical new biotechnological batch plant based on the information of real known processes for the production of the four recombinant protein products. The real plant was divided for practical purposes into two sub-processes or facilities: a fermentation facility and a purification facility. Knowing the specific steps conforming the downstream processing of each product, size, and time factors were computed and used as parameters to solve the aforementioned MILP reformulation. New constraints were included to permit the selection of some equipment-such as centrifuges and membrane filters-in a discrete set of sizes. For equipment that can be built according to customer needs-such as reactors-the original formulation was retained. Computational results show the ability of this optimization methodology to deal with real data giving reliable solutions for a multi-product batch plant composed of 44 unit operations in a relatively small amount of time showing that in the case studied it is possible to save up to a 66% of the capital investment in equipment given the cost data used. Biotechnol. Bioeng. 2017;114: 1252-1263. © 2017 Wiley Periodicals, Inc.

Selection of process alternatives for lignocellulosic bioethanol production using a MILP approach.

This work proposes a decision-making framework for the selection of processes and unit operations for lignocellulosic bioethanol production. Process alternatives are described by its capital and operating expenditures, its contribution to process yield and technological availability information. A case study in second generation ethanol production using Eucalyptus globulus as raw material is presented to test the developed process synthesis tool. Results indicate that production cost does not necessarily decrease when yield increases. Hence, optimal processes can be found at the inflexion point of total costs and yield. The developed process synthesis tool provides results with an affordable computational cost, existing optimization tools and an easy-to-upgrade description of the process alternatives. These features made this tool suitable for process screening when incomplete information regarding process alternatives is available.