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There has been an increasing interest in the conversion of biomass to biofuels, energy, and chemicals due to an increase in meeting environmental demands and price and decrease in the potential ava...

Butanol is an interesting biofuel and a product precursor, that could be obtained with acetone and ethanol via fermentation. The biofuels production has been identified as not economically competitive, thus, the parallel production of high value-added products, such as xylitol, could be an alternative to improve the profit. Xylitol can be produced from xylose, which might be considered as a coproduct in a second generation biorefinery. This study presents a systematic biorefinery process design for the simultaneous acetone, butanol, ethanol (ABE) and xylitol production, based on experimental and simulation approaches. Experiments were performed for the pretreatment of sugarcane bagasse and ABE fermentation. The simulation part used the experimental results and experimental data from literature, to perform rigorous calculations of the ABE and xylitol production process. The economic analysis (EA) was performed relying on some indicators such as, the net present value (NPV) and payback period (PBP); EA includes several scenarios for producing only ABE and some scenarios for simultaneous ABE and xylitol production. The results showed that the combined butanol and xylitol production could reduce by 17% the selling price of butanol, compared with only producing butanol. The study also included the combustion of residual solids and carbon dioxide depletion analyses. This approach illustrates the opportunity to perform a rigorous techno-economic analysis, to identify the feasibility of the process at industrial scale, based on realistic data. This approach was implemented for ABE and xylitol production, but it can be used to any other bioproduct.

Methyl ethyl ketone (MEK) is a widely used chemical in the industry. Most of the MEK uses are directly related to industrial application; however, recent studies suggest the use of MEK as a possible fuel for spark-ignition engines. The industrial process to produce MEK is performed through the hydration of butylene and the dehydration of that alcohol. Butylene is produced from oil cuts. However, petroleum is a recognized finite resource and is pointed out as a major cause of environmental issues. An alternative to improve a process is process intensification (PI). In this work, an intensified alternative to produce MEK from 2,3- Butanediol is proposed. 2,3-Butanediol might be produced by a fermentation process based on renewable biomass. The intensified alternatives consist of a reactive distillation column, an extractive distillation column, and three conventional distillation columns. The novel alternatives produce and purify MEK, 1,2-BD, 2MPL, and water, from 2,3-BD using calcium phosphate as catalyst were modelled in Aspen Plus. To evaluate the intensified alternative, it was considered the energy requirements per kilogram of MEK, conversion, selectivity as well as an environmental impact index, the greenhouse gas emissions. The RD column resuzlted in a conversion of 99.86 % and a selectivity for MEK of 44 %. After evaluation, the direct scheme resulted as the most promising one, with energy requirements of 2790 kcal/kgMEK (11.6 MJ kg/MEK). Regarding the environmental impact, the direct scheme reported 7.07 tCO2/h of greenhouse gas emissions.

In the last decades, the need of cleaner and renewable fuels has increased the use of alcohols to power internal combustion engines. The ABE (acetone–butanol–ethanol) method to produce purified biobutanol and bioethanol is the most known and well-studied method to produce those alcohols. Nevertheless, it is not yet clear how the bioethanol’s content in the biobutanol stream could affect the engine’s biofueled performance. Thus, this study focuses on (1) the performance of an internal combustion engine and (2) on the different compositions of n-butanol/ethanol mixtures, up to 20 vol%, to assess the operative issues of the use of both alcohols instead of pure n-butanol. In order to get the most reliable results of the engine’s performance, we conducted three different experiments for each alcohols’ composition, including conventional gasoline testing as reference. The experimental tests were carried out in a CT 150 Internal Combustion Engine Basic Module and conducted at various speeds—from 700 to 1500 rpm—resulting in load variation. In general, the changes in the composition of ethanol in n-butanol do not seem to affect the performance of the engine considerably, as variations occur at an approximate rate of 3.7% in effective power, 3.3% in torque and 5.4% in specific fuel consumption.

Alkoxysilanes are silicon compounds containing a Si-OR bond. The applications of tetraalkoxysilanes cover a wide range depending if the Si-OR bond remains intact or is hydrolyzed. Currently, tetraethoxysilane (TEOS) is the most prominent derivative of such silicon compound family. The best known and used method of synthesis of TEOS is the esterification reaction of SiCl4, following the old Von Ebelman’s route (1846). Tetramethoxy- and tetraethoxysilane are obtained by a technology developed in the 1990’s involving the catalyzed direct synthesis of silicon metal and either methanol or ethanol. However, there is few information about novel technologies to produce TEOS, either improved current technology or proposed new approaches. In this work, the reactive distillation (RD) is suggested to produce TEOS as an intensified technology. In general, the concept of process intensification may overcome the traditional process, since it allows design technology with reduction on equipment size, improvement in energ...

Combustion of residual (waste) biomass represents an environmental hazard and a lost economic opportunity. The production of specialty chemicals provides a more attractive pathway to dispose of residual biomass; however, a problem that arises in recovering products from waste is that there are currently no well-established markets that bring together all stakeholders involved (e.g., biomass production, collection, transportation, and processing). In this context, coordination is essential as all the stakeholders in the supply chain (SC) depend on the revenue generated from the derived products. In this work, we propose a market coordination framework for the production of levulinic acid and furfural from lignocellulosic biomass (obtained from agricultural residues). Coordination brings a number of important economic benefits that would be difficult to achieve under existing markets (which are uncoordinated and based on peer-to-peer transactions). We demonstrate insights provided by our framework by using a case study for the State of Guanajuato in Mexico. Our results indicate that production of 330,000 tonnes per year of levulinic acid and 394,000 tonnes per year of furfural can be achieved. This constitutes 3% of the annual global demand for methyltetrahydrofuran. The SC is designed around a single biorefinery and the SC creates a total value of 3.57 billion USD per year and draws 64.65% of the available biomass supply. Our results also indicate that this market would avoid the generation of 850,000 tonnes of CO2 annually (corresponding to a 34% reduction in emissions from the combustion of agricultural residues). As such, the deployment of such a market can bring both economic and environmental benefits.

Methyl-Ethyl Ketone (MEK) is a promising bulk chemical and can be produced in a biochemical route from biomass. Within this route, two azeotropes are formed because of the intermolecular interactions; thus, the purification of that mixture is difficult. In this study, a work of synthesis, design, and multi-objective optimization was carried out to generate sustainable alternatives to purify MEK, starting from a promising alternative previously reported. Those alternatives are hybrid processes that combine the advantages of using a liquid-liquid extraction column for handling the azeotropes aforementioned. All alternatives were modeled in Aspen Plus and were optimized using a hybrid stochastic optimization algorithm. As a result, interesting trends among objectives and design variables were found. Additionally, the thermally coupled alternative was shown as a promissory alternative with savings of 11%, 12% for the economic and environmental impact. Also, it showed improvements in controllability and no real penalty regarding safety issues in comparison with a case base.

Agricultural residues are considered abundant raw materials that can be used to produce valuable chemicals like furfural. Currently, furfural production is characterized by extensive use of energy and low conversions. However, these challenges can be overcome through process intensification in conjunction with a suitable process synthesis. This work proposes the synthesis, design and optimization of furfural production processes using different intensified distillation and pretreatment alternatives. The eco-indicator 99 and total annual cost were considered as metrics to evaluate the performance of furfural processes. To determine the influence of biomass type on energy consumption, costs and environmental impact, four different biomasses are considered raw materials. The design and optimization of furfural processes were carried out using a two-step procedure. Firstly, all possible alternatives were simulated using Aspen Plus, then the best process option for each biomass is optimized using the differential evolution with tabu list method. The results indicate that a dilute acid pretreatment combined with a thermally coupled scheme provides the lowest cost and environmental impact for all feedstocks. Finally, the optimization results show that the best furfural process consists of wheat straw, dilute acid pre-treatment and thermally coupled distillation, owing to its lowest cost and environmental impact which are 13,092,504 dollars/year and 4,536,512 eco-points/year respectively.

This paper presents a multiobjective optimization to obtain the optimal planning of butanol production, considering the optimal selection of feedstock and the correct ratio of fermentable sugars. This multiobjective methodology was applied during both the fermentation and purification process of butanol. The multiobjective optimization problem considers minimizing the total annual cost and environmental impact as objective function. The economic objective function takes into account the availability of bioresources, the cost of feedstocks, the fermentation conditions, and the separation units. On the other hand, the environmental assessment includes the overall impact measured through the eco-indicator 99 which is based on a life cycle analysis methodology. Both objective functions were applied to a case study for the optimal planning to produce biobutanol in Mexico. After the optimization process, we generated a set of solutions represented by a Pareto curve that identifies a group of optimal solutions f...

In this work the design, synthesis and optimization of a furfural production plant, considering the most abundant and common lignocellulosic wastes of Mexico is proposed. For the process, different pretreatment technologies and different purification process including intensified schemes are considered giving a total of 32 possible process alternatives. The pretreatment technologies are the dilute acid (DA) and ammonia fiber explosion (AFEX) respectively, for the separation zone we considered an azeotropic distillation process, a thermally coupled scheme distillation, a dividing wall column and one liquid- liquid extraction process. A two-stage procedure is used to determine the best process per biomass type. First, the processes are modelled in Aspen plus. Next, the best option per biomass is optimized using the differential evolution with tabu list in order to minimize the total annual cost and the environmental impact. The prescreening results indicate that the dilute acid pretreatment and the thermally coupled distillation provide the lowest cost and environmental impact for furfural production for all the raw materials. The optimization results indicate that a biorefinery with wheat straw as raw material is the best option to produce furfural due to its low cost and environmental impact which are 13 M$/yr and 4,536,512 eco-points/year respectively.

Butanol is an alternative fuel with characteristics competitive to petroleum-based fuels. Compared with ethanol, butanol shows less miscibility, flammability, and corrosion; while potentially replacing gasoline in car engines without modifications. However, the production cost of butanol from renewables feedstock, i.e. bio-butanol (which also contains acetone and ethanol) through fermentation remains high. This is mainly due to the low yield of butanol in fermentation. The conventional recovery of butanol by distillation is an energy-intensive operation that has greatly restricted the industrial production of bio-butanol. This work studies ten hybrid and intensified configurations, based on the liquid-liquid extraction and dividing wall columns, to purify the butanol to the fuel grade. The study analyzes sustainability based on green metrics, including the inherent safety and control properties using singular value decomposition analysis. The results indicate that as long as the process is highly intensified, the sustainability and the inherent safety are improved and not necessarily the control properties. This is primarily due to the loss in the degrees of freedom in intensified processes.

Methyl-Ethyl Ketone (MEK) is a promising bulk chemical due to its several applications. MEK can be produced by hydrogenation of 2, 3-Butanediol, a chemical previously produced by fermentation. As hydrogenation results, the output is composed of water, isobutyraldehyde, 2, 3-Butanediol, and Methyl-ethyl ketone. Because of the thermodynamic interactions, two azeotropes are formed; consequently, the purification of that mixture is challenging. Current needs promote the generation of alternatives with good economic and environmental performance, however, inherent safety and good controllability must also be accomplished. In this study an intensified process is proposed to reduce the energy investment for MEK purification. The alternative is a hybrid process that combines the advantages of using a liquid-liquid extraction column for handling the azeotropes aforementioned. Additionally, this proposal is compared with four alternatives previously proposed based only on distillation. All alternatives were modeled in Aspen Plus and were optimized considering four targets, the total annual cost, the eco-indicator 99, the individual risk, and the condition number as economic, environmental, safety and controllability indexes, respectively. As a result, interesting trends among objectives and design variables were found. Additionally, the intensified design reported an energy investment of 6.78 MJfuel/kgMEK, and the best pure distillation alternative 35.5 MJfuel/KgMEK.

Acetone, butanol, and ethanol are produced in an acetobutylic fermentation, butanol being the main interest product because of its superior properties making it a feasible substitute for fuels coming from fossil sources. In this work we have simulated and optimized under a rigorous scheme an integrated process to produce acetone, butanol, and ethanol from lignocellulosic biomass. Since ABE fermentation presents several hurdles such as low concentration broths or inhibitory effects during fermentation, here is proposed a hybrid simultaneous system of saccharification–fermentation–separation in which inhibition products during both fermentation and enzymatic hydrolysis are limited. A liquid–liquid extraction step is selected as the recovery technique. The reactor was modeled and simulated using Matlab software coupled with Aspen Plus which simulated the separation step. The entire optimization was developed taking into consideration several objective targets such as the total annual cost and some bioindexes...

Solar cell manufacturing is based on solar grade silicon which can be obtained using silane as precursor. Silane is produced by redistribution reactions of trichlorosilane. The aim of the present work is to study the control properties of a multitasking reactive distillation column to produce silane, dichlorosilane and monochlorosilane. Control adjustment was defined in such way that the column may work in multitasking mode producing the three interest components in high purity. Several control strategies were studied to define the best dynamic performance which allow to produce those three components within the same column. In order to observe the dynamic behavior of the multitasking reactive distillation column, this system was tested under various control strategies: temperature, composition and cascade (temperature/composition), having as target to keep silanes purity in 99.5%mol. The results indicated that is possible to obtain a conceptual design of a single reactive distillation column which would be able to produce all products. The proposed multitasking column avoids all hurdles involved in the traditional way to produce and purify all those three components. It was observed those evaluated control structures can stabilize the system against tested disturbances, even the simplest temperature control structure.

BACKGROUND Butanol produced from fermentation has attracted the interest of research groups because its physicochemical properties show several enhancements over bioethanol. Recent studies have proposed alternative methods to separate and purify biobutanol from a fermentation broth. These alternatives offer energy and economic savings; in addition, a reduction in environmental impact is observed. However few studies have analyzed the control properties of the process which involves separation of an acetone–butanol–ethanol (ABE) mixture. RESULTS A controllability analysis using the singular value decomposition technique and a closed-loop dynamic analysis was performed on several hybrid distillation processes including conventional, thermally coupled, thermodynamically equivalent and intensified designs. The results indicated that under the closed-loop control policy, an intensified design which is integrated for only two distillation columns instead of three distillation columns, showed good dynamic properties. In addition, thermally coupled sequence A showed better control properties under open-loop analysis. CONCLUSIONS Using both SVD analysis and closed-loop tests the dynamics properties were obtained for several hybrid processes to separate an effluent produced by fermentation. It was possible to control all schemes under both methodologies and it was clear that when the base case became more complex with thermal coupling, section movement or elimination of a column section improved the control properties. © 2016 Society of Chemical Industry

Furfural is one of those promising chemicals obtained from biomass that is able to compete with petrochemicals. The purification of furfural is one the most critical stages during its production process, due to it requires a great amount of energy. In this sense, liquid-liquid extraction is one of the most promising alternatives. However, the main disadvantage of this alternative is the losses of co-products, which reduces the profitability of the process. This is work is one of the first to show the separation of coproducts of a purification process of furfural-based liquid-liquid extraction. Different intensified alternatives were tested in order to determine the best separation process for purifiying coproducts. The total annual cost, eco-indicator 99, the individual risk and the condition number were used to evaluate economic, environmental, safety and controllability aspects respectively, of the separation alternatives. The results indicate that the intensified alternatives have a reduction on total annual cost and environmental impact of around 25 %, while the improvements on the risk index is around 4 %. To conclude, an indirect intensified alternative was selected as the best option due to an improvement in cost and environmental impact, important risks reduction and similar control properties than those of conventional schemes.

In this work have been designed and optimized simultaneously three different process separations for purify furfural, using Differential Evolution with Tabu List Algorithm. The study cases are a conventional Quaker Oats process, a thermally coupled process and liquid-liquid extraction process. The objective of this work is select the best alternative to purify furfural taken into consideration economic, environmental and safety issues. The results show which the thermally coupled process has several improvements and reductions on the risk, similar cost and environmental impact compared with Quaker Oats process. While the liquid-liquid extraction process does not have any improvement in the objective function, these results are associated with the use of entrainer in this sequence with respect to Quaker Oats Process. Therefore, due to the important improvements in safety issues the TCP process is choosing as the best alternative.

The design of optimal sustainable processes must be performed relying on systematic steps, which must guide the users to take the best decision in terms of given objectives. This study proposes and implements a framework consisting of organized steps combining methods and tools, using as a case study the separation and purification of the acetone-butanol-ethanol (ABE) mixture obtained from a fermentation broth. A feasible configuration to that end includes the use of liquid-liquid extraction (LLE) columns followed by conventional distillation columns. Thus, the framework includes a molecular design step to tailor-made the extractant agent employed in the LLE unit with the desired properties, the process design of the required equipment for the ABE separation, and finally an optimization step using a hybrid stochastic optimization method, differential evolution with taboo list. The results allowed to reduce the total annual cost by 67 % and the environmental impact by 72 % relying on the eco-indicator.

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.

Current research focuses on new energy alternatives which could compete with the traditional energy sources based on fossil fuels, and eventually diminish the consequences on climate. Recently, butanol produced by ABE fermentation attracted more attention since its energy power is comparable to that of gasoline. But some hurdles are involved in the establishment of this fuel as an immediate substitute of fossil fuels, e.g. lower butanol concentration in the fermentation effluents and the expensive separation steps to purify the effluent. This work is the first to report the use of hybrid separation based on liquid-liquid extraction (LLX) combined with dividing-wall column (DWC) technology for the purification of the ABE (acetone-butanol-ethanol) mixture. The configurations proposed are the result of multi-objective optimization that aims to find designs that fulfill the tradeoff between those objectives: cost minimization, reduce environmental impact, and increase controllability. The downstream processing alternatives are designed and optimized by minimizing three objective functions simultaneously: the total annual cost (TAC) as an economical index, the eco-indicator 99 as an environmental function, and the condition number (CN) as control index. Among the four designs, the scheme where only a reboiler is included showed the best economic performances and relatively good values of condition number and eco indicator 99.

In the continuous search for the improvement of processes, recently, alternative schemes have been proposed to separate and purify levulinic acid produced from the acid hydrolysis of biomass. These alternatives offer both energy and economic savings, and reduction of environmental impact; however, their control properties have not been considered for possible industrial implementation. In this work, a controllability analysis was carried out of previously optimized designs using the relative gain array (RGA), the total condition number (TCN) and a sensitivity index for performance assessment in open-loop. Finally, the dynamic performance in closed-loop is evaluated using PI controllers having as criteria the integral absolute error (IAE). Through analysis, the best scheme obtained presented a low total condition number, however, its sensitivity index is below the average of all the designs analyzed. Additionally, the RGA analysis shows a stable structure in the frequencies studied keeping low values of eco-indicators 99 and total annual cost. The general topology consists of a liquid-liquid extraction column, a conventional distillation column and a dividing wall column with a decanter. On the other hand, by means of this robust analysis of the control properties was proposed some guidelines between the structure for improving control properties in intensified distillation schemes.

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.

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.

Biobutanol is receiving great interest from both the academia and industry sectors, and some companies are already focusing on revamping bioethanol plants to produce biobutanol. The recovery of fuel grade butanol by distillation was proven not to be economically sustainable. On the other side, hybrid flowsheets, obtained with the combination of liquid–liquid extraction and distillation, were proposed as a more convenient alternative. Divided wall columns (DWCs), as one of the most promising intensified distillation alternatives, were here explored in combination with liquid–liquid extraction. A multiple-objective function, taking into account the economy, the environmental impact, and the process controllability, was defined to screen the alternatives. Among all the configurations considered, liquid–liquid extraction combined with a DWC equipped with two reboilers and a side rectifier, reached 22% and 18% reduction of the economy and environmental index, respectively. At the same time, also the controllability was improved compared to the hybrid liquid–liquid-assisted simple column distillation sequence considered as a reference.

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.

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.