Eduardo Sánchez-Ramírez

Synthesis and design of new hybrid configurations for biobutanol purification

Abstract The development of new technologies for biobutanol production by fermentation has resulted in higher butanol concentrations, less by-products and higher volumetric productivities during fermentation. These new technology developments have the potential to provide a production process that is economically viable in comparison to the petrochemical pathway for butanol production. New alternative hybrid configurations based on liquid–liquid extraction and distillation for the biobutanol purification were presented. The alternatives are designed and optimized minimizing two objective functions: the total annual cost (TAC) as an economical index and the eco-indicator 99 as an environmental function. All the new configurations presented reduced the TAC compared to the traditional hybrid configuration, in particular a thermally coupled alternative exhibited a 24.5% reduction of the TAC together with a 11.8% reduction of the environmental indicator. Also intensified sequences represented a promising option in the reduction of the TAC but with some penalty in the eco-indicator.

Alternative Hybrid Liquid-Liquid and Distillation Sequences for the Biobutanol Separation

Abstract Recent technologies for biobutanol production by fermentation have resulted in higher final biobutanol concentrations, less fermentation by-products and higher volumetric productivities during fermentation, together with less energy intensive separation and purification techniques. These new technology developments have the potential to provide a production process for biobutanol that is economically viable in comparison to the petrochemical pathway for butanol production. This study compares four different possible process designs for purification of biobutanol by means of a multiobjective optimization process having two objective functions: the total annual cost (TAC) as an economical function and the associated eco-indicator 99 as an environmental function.

Economic and environmental optimization of the biobutanol purification process

Current technologies for the production of biobutanol by fermentation have improved the production processes. These new technology improvements are economically viable with respect to the petrochemical pathway. For this, the aim of this paper is to compare four different process designs for the purification of biobutanol by solving a multi-objective optimization process involving two objective functions: the total annual cost and return of investment as economic functions and the associated eco-indicator 99 as an environmental function. The process associated to the routes A, B, and C consists of a steam stripping distillation and distillation columns, while the process D includes distillation columns with a liquid–liquid extraction column. Process modeling was performed in the Aspen Plus software, and the multi-objective optimization was conducted using differential evolution with tabu list as a stochastic optimization method. Results indicate that the process route D is the most profitable design and the process route C has the lowest environmental impact measured through the eco-indicator 99 method. Additionally, the use of a solar collector against steam has been compared in order to produce the required heat duty needed in every single distillation column to have a broader view about the environmental and economic impact of these devices.

Processes Separation to Furfural, Design and Optimization Involving Economical, Environmental and Safety Criteria

Abstract In this work is presented the simultaneous design and optimization of three alternatives of azeotropic distillation processes to purify Furfural by the mathematical technique called Differential Evolution with Tabu List (DETL), having as objective functions economic, environmental and safety criteria to the processes were evaluated. The schemes here studied are: conventional Quaker Oats process to purification of Furfural (CQO), an azeotropic distillation process with heat integration through vapour recompression (DHI) and dividing wall azeotropic distillation column (DWC). The results of the simultaneous optimization show that the intensification processes DHI and DWC have important reduction on the cost and environmental impact, with respect to conventional process (CQO). However, the increase in operative pressures in the case of DHI process and the increase of internal flows and the size of equipment in DWC process cause an increment of the risk, despite of the risk increment in DWC it is considered the best option to furfural purification due reductions mainly on TAC and Eco99 that mean important savings in a long-term.

Energy, exergy and techno-economic analysis for biobutanol production: a multi-objective optimization approach based on economic and environmental criteria

Currently, butanol obtained by fermentation is considered as potential biofuel. In this work, it has been simulated and optimized a process to produce acetone, butanol and ethanol by means of lignocellulosic material. To accomplish this task, initially, it was planned the raw material selection, followed by the simulation in MATLAB of simultaneous saccharification, fermentation and separation reactor (SFS) and finally, the stream coming from fermentation was purified. The separation stage was selected from three different options to purify that effluent. The entire process was evaluated under a robust optimization process considering environmental, economic and energetic objective functions by means of a hybrid stochastic method, differential evolution with tabu list. The obtained results showed that the best scheme to produce and purify butanol was the SFS-3C, which considers thermally coupled columns to purify acetone, butanol and ethanol. In general terms, it was obtained as result 0.138

Biobutanol purification by hybrid extraction-divided wall column configurations

/kgbutanol, 0.132 points/kgbutanol and 66.8 regarding to the total annual cost, environmental impact and exergy efficiency, respectively.

Planning of biobutanol production considering raw material availability: economic and environmental optimization

The synthetic production of butanol has completely substitute the original fermentation process where butanol, acetone and ethanol were simultaneously produced in the so called ABE process. As most of the bio-alcohols produced by fermentation, the dilution in water makes their separation challenging due to the presence of azeotropes. The bio-related process competitiveness, in economic terms, is mainly related in developing energy efficient separation alternatives to reach the market grade purity. Distillation, is one of the preferred separation technique, but it suffers of a low thermodynamic efficiency. Anyway, distillation still represents an efficient separation method if properly combined with other unit operations in hybrid flowsheets. In particular, in the present work, liquid-liquid extraction is considered to separate water from the fermentation broth. Then, the quaternary mixture composed by the extraction solvent, acetone, butanol and ethanol could be efficiently separated by distillation. First, the simple column configurations (SCCs) were designed and optimized minimizing the total annual cost, the eco-indicator 99 and the condition number as multi-objective function. The combined extraction-indirect configuration was selected as best SCC. Starting from this reference different ternary DWC arrangements were proposed. Among all the alternatives, it was obtained that, after the extraction, is more convenient to remove the solvent in a simple column and proceeds with the separation of acetone, ethanol and butanol in a DWC. For this arrangement the objective functions are lower compared to the hybrid extraction- simple indirect configuration. In particular, a remarkable 16% reduction in the total annualized cost was reached.

A Framework for an Optimized Sustainable Product and Process Design: Acetone-Butanol-Ethanol Separation and Purification

The increasing world energy demand has motivated the research of alternative energy sources to the fuels from fossil sources. Due to the physicochemical properties that butanol presents, mainly the energy content, has increased the interest for its development by means of the fermentative route with the intention of implement it as fuel. In this work we developed a complete framework to produce biobutanol focused on the correct planning of lignocellulosic biomass as raw material throughout the months of the year. The correct selection of raw material has been planned to obtain the best performance in an integrated reactor measured by energy requirements, costs and environmental impact. The purification process was simulated in Aspen Plus. As concern to the purification process, we considered three different separation schemes searching to minimize the total annual cost (TAC) and the environmental impact measured by the ecoindicator 99 (EI99). To evaluate such indicators, a multi-objective optimization process was performed by means of a stochastic optimization algorithm, differential evolution with tabu list (DETL).

Economic, Environmental and Dynamic Optimization Applied to Hybrid Processes for the Purification of Biobutanol

The biobutanol production have gained special attention due to diverse positive characteristics compared with bioethanol, but one of the paramount problems is found at the downstream processes section. In order to tackle that issue, a systematic framework for sustainable product and process design including the optimization of the problem considering economic and environmental aspects, could be identified as a supportive solution. Thus, this study proposes and implements a framework consisting of organized steps combining methods and tools, using as a case study the acetone-butanol-ethanol separation. The process configuration included a liquid-liquid extraction unit that allowed the molecular design of the extracting agent, followed by the process design of the required equipment, and finally by an optimization step using a hybrid stochastic optimization method, the differential evolution with tabu list. The results allowed to reduce the total annual cost by 22 % and the environmental impact by 28 % relying on the eco-indicator.

Process Alternatives for Biobutanol Purification: Design and Optimization

Abstract Biobutanol is more energy dense and less hygroscopic than bioethanol, resulting in higher possible blending ratios with gasoline. Recently, new developments are focused on diminish the impact in two zones, the strains improvements and the downstream processes. Recent studies conclude that the inclusion of an extractive column can diminish the economic impact. In this study several hybrid designs are compared from a multi-objective optimization perspective where three objective function are evaluated simultaneously, the total annual cost as economic target, theeco-indicator 99 as environmental target and the condition number as controllability index using a stochastic hybrid algorithm, Differential Evolution with Tabu List. Our results indicate that the intensified configuration show the best dynamic behavior in addition with the smallest TAC values with a slightly penalty in the eco indicator values.