Urban mining from fly ash resulting from municipal solid waste incineration (MSWI) is becoming more and more important due to the increasing scarcity of supply-critical metals. Metal extraction from acid fly ash leaching has already been established. In this context selective Cu recovery is still a challenge. Therefore, our purpose was the separation of Cu(II) from MSWI fly ash extracts by polymer-assisted ultrafiltration (PAUF). We investigated three polyethyleneimines (PEIs) with regard to metal retention, Cu(II) selectivity, Cu(II) loading capacity, and the viscosity of the PEI containing solutions. A demanding challenge was the highly complex matrix of the fly ash extracts, which contain up to 16 interfering metal ions in high concentrations and a chloride content of 60 g L−1. Overcoming that, Cu(II) was selectively enriched and separated from real fly ash extract at pH 3.0. At pH 1.0, a PEI-free Cu(II) concentrate was obtained and PEIs could be regenerated for reuse in further sep... [more]

Porphyridium spp. is a debated family that produces phycoerythrin (PE) for use in multiple industrial applications. We compared the differences in the biochemical composition and phycoerythrin yield of P. cruentum and P. purpureum by conventional and green extraction technologies. The protein content in P. cruentum was 42.90 ±1.84% w/w. The omega-3 fatty acid (FA) was highlighted by eicosapentaenoic acid (EPA, C20:5, ω-3, ~9.74 ± 0.27% FA) and arachidonic acid (ARA, C20:4, ω-6, ~18.02 ± 0.81% FA) represented the major omega-6 fatty acid. Conversely, P. purpureum demonstrated a higher lipid content (17.34 ± 1.35% w/w) and an FA profile more saturated in palmitic (C16:0, 29.01 ± 0.94% FA) and stearic acids (C18:0, 50.02 ± 1.72% FA). Maceration and freeze/thaw were the conventional methods, whereas microwave (MW) and ultrasound (US) served as green procedures for PE extraction under the factorial-design methodology. Aqueous solvents, extraction-time and power were the main factors in the... [more]

This paper provides a multi-aspect comparison of selected methods of ethyl acetate production and shows the possibility of further reactive distillation process integration and sophisticated intensification including process stream regeneration. The production pathways were selected with respect to their practical applicability and sufficient experimental and feasibility studies already published. A total of four case studies were designed and compared: conventional process set-up (ethyl acetate is produced in a chemical reactor) is designed as a base case study; reactive distillation with a separation unit is derived from the conventional process set-up. The mechanical and chemical approach to reactive distillation process intensification and integration were assumed: reactive distillation column with a stripper and reactive distillation column with an auxiliary chemical reaction (ethylene oxide hydration). Process models were compiled in the Aspen Plus software. Complex process flows... [more]

Supercritical assisted Liposome formation (SuperLip) is a lab-scale process for the production of liposomes. SuperLip was recognized as being a versatile supercritical assisted technique for the encapsulation of molecules for different industrial applications, such as pharmaceutic, cosmetic, textile, and nutraceutic purposes. The aim of this work was to perform an economic analysis to assess the profitability of the SuperLip process. The liposomes market was analyzed and the SuperLip process was compared to other techniques in terms of manufacturing advantages using the Canvas and Strengths, Weaknesses, Opportunities, and Treats (S.W.O.T.) models. SuperLip Plant Capital Expenditures (CAPEX) were estimated, and plant Operating Expenditures (OPEX) were also evaluated and integrated with personnel cost and other plant goods and services. A profit and loss statement was generated, together with a cash flow analysis. According to the market average selling price, liposome price is 1.8 €/mL;... [more]

Since humanity has been able to transform materials, such as raw minerals, and produce food or beverages, a central question was the type of operation and how and where it should be performed [...]

Biorefineries are novel, productive models that are aimed at producing biobased alternatives to many fossil-based products. Biomass supply and overall energy consumptions are important issues determining the overall biorefinery sustainability. Low-profit lands appear to be a potential option for the sustainable production of raw materials without competition with the food chain. Cardoon particularly matches these characteristics, thanks to the rapid growth and the economy of the cultivation and harvesting steps. An integrated biorefinery processing 60 kton/y cardoon lignocellulosic biomass for the production of 1,4-butanediol (bio-BDO) is presented and discussed in this work. After designing the biorefinery flowsheet, the mass and energy balances were calculated. The results indicated that the energy recovery system has been designed to almost completely cover the entire energy requirement of the BDO production process. Despite the lower supply of electricity, the energy recovery syste... [more]

The main objective of this study was to evaluate the hydrothermal pretreatment’s retention time influence on the volatile fatty acids and biomethane production from thickened waste activated sludge under mesophilic conditions. Six different retention times of 10, 20, 30, 40, 50, and 60 min were investigated while the hydrothermal pretreatment temperature was kept at 170 °C. The results showed that the chemical oxygen demand (COD) solubilization increased by increasing the hydrothermal pretreatment retention time up to 30 min and stabilized afterwards. The highest COD solubilization of 48% was observed for the sample pretreated at 170 °C for 30 min. Similarly, the sample pretreated at 170 °C for 30 min demonstrated the highest volatile fatty acids yield of 14.5 g COD/Lsubstrate added and a methane yield of 225 mL CH4/g TCODadded compared to 4.3 g COD/Lsubstrate added and 163 mL CH4/g TCODadded for the raw sample, respectively. The outcome of this study revealed that the optimum conditio... [more]

Design as a discipline has changed a lot during the last 50 years. The boundaries have been expanded partially to address the complexity of the problems we are facing nowadays. Areas like sustainable design, inclusive design, codesign, and social design among many more have emerged in response to the failures of the production and consumption system in place. In this context, social, environmental, and cultural trends have affected the way artefacts are designed, but the design process itself remains almost unchanged. In some sense, more criteria beyond economic concerns are now taken into consideration when social and environmental objectives are pursued in the design process, but the process to reach those objectives responds to the same stages and logic as in traditional approaches motivated only by economic aims. We propose in this paper an alternative way to understand and represent the design process, especially oriented to develop innovations that are aligned with the social, en... [more]

The present work aimed to design a separation process for 2-phenylethanol (2-PEA) produced by whey fermentation and to evaluate its economic potential. The separation sequence consisted of a liquid−liquid extraction column followed by two distillation columns for 2-PEA purification and solvent recovery. In addition, the use of ethyl acetate as a solvent for the extraction process was analyzed. The results, aided by the Aspen Plus v.10 process simulator, showed that 2-PEA can be separated with a purity of 96% by weight. The operating cost of the process, estimated at USD 22.70 per kilogram, shows that the separation alternative developed in this work has a high economic potential. The use of ethyl acetate as a solvent was found to efficiently remove 2-PEA from the fermentation mixture. From a process safety analysis point of view, the use of a bioprocess safety index developed in this work identified the separation process sections that could require special attention as part of the saf... [more]

A hybrid system based on lignocellulosic biomass gasification and syngas fermentation represents a second-generation biorefinery approach that is currently in the development phase. Lignocellulosic biomass can be gasified to produce syngas, which is a gas mixture consisting mainly of H2, CO, and CO2. The major challenge of biomass gasification is the syngas’s final quality. Consequently, the development of effective syngas clean-up technologies has gained increased interest in recent years. Furthermore, the bioconversion of syngas components has been intensively studied using acetogenic bacteria and their Wood−Ljungdahl pathway to produce, among others, acetate, ethanol, butyrate, butanol, caproate, hexanol, 2,3-butanediol, and lactate. Nowadays, syngas fermentation appears to be a promising alternative for producing commodity chemicals in comparison to fossil-based processes. Research studies on syngas fermentation have been focused on process design and optimization, investigating th... [more]

The aim of this paper is to study the effect of reinking and pretreatment of waste banknote paper on its usability in the bioethanol production process. To this end, the tensile strength of worn banknote paper was first studied at different pH values. The sample with the lowest tensile strength was considered for the next sections. In the deinking process, NaOH at different concentrations (1%, 2%, 3%, and 4%) and in combination with ultrasonic treatment was applied. After deinking the pulp, two acidic and alkaline chemical pretreatments with concentrations of 1%, 2%, 3%, and 4% were used independently and in combination with ultrasonic. Enzymatic hydrolysis, following fermentation with Scheffersomyces stipitis, and crystallinity measurements were used to confirm the efficiency of the pretreatments. RSM Design Expert software was used to determine the optimal values by considering the three variables—enzyme loading, ultrasonic loading, and contact time for waste paper deinked (WPD) and... [more]

In order to make anaerobic digestion-based processes for short chain organic acid (SCOA) production attractive, the key performance variables, i.e., concentration, yield, and productivity of the produced SCOAs need to be maximised. This study analysed recent literature, looking for the effect of process operating parameters (feed concentration, pH, temperature, and residence time) on the performance variables. Data from 551 experiments were analysed. Mean values of the SCOA concentration, yield, and productivity were 10 g l−1, 32% (chemical oxygen demand (COD) COD−1), and 1.9 g l−1 day−1, respectively. Feed concentration and residence time had the most important effect. Higher feed concentration corresponded to higher product concentration and productivity, but to lower yield. The mean feed concentration was 109 gCOD l−1 and 19 gCOD l−1 in the experiments with the highest product concentrations and in the experiments with the highest yields, respectively. Shorter residence times corres... [more]

To reduce the anthropogenic CO2 emissions produced from fossil fuel burning plants, the application of carbon capture and storage (CCS) is necessary and development of a more efficient and economically feasible CO2 capture process is essential as an alternative to the conventional amine scrubbing process which uses aqueous amine solutions. CO2 capture can be enhanced by improving both the gas−solid contact efficiency and by tuning a specific high-performance sorbent. The aim of this research is to investigate the adsorption of CO2 using impregnated mesoporous silica in a “confined-fluidized bed”. This non-conventional fluidized bed (sometimes also termed the “packed-fluidized bed”) seems suitable for improving the efficiency of gas−solid processes for which the bypass effect of the gas−solid contact caused by bubbling represents a major drawback. Results, expressed as grams of CO2 adsorbed per kilogram of material, are discussed in terms of amine load in the sorbent, breakthrough time... [more]

Due to its low operating temperature, the performance of a methanol steam reformer depends on efficient thermal integration. In particular, the integration of the evaporator is crucial to enhance thermal efficiency. This paper presents two different configurations to utilize thermal energy for evaporation of methanol/water mixture. The reformer system is composed of a methanol steam reformer, a burner, and two different evaporators such as internal evaporator and external evaporator. Moreover, since the performance of the reforming system strongly depends on thermal utilization, a heat recovery module is designed for methanol reforming system with internal evaporator. The heat duty and steam to carbon ratio (S/C) are the variables for evaluation of its suitability. The experimental results indicate that the internal evaporator with the auxiliary heat recovery module provides stable conditions over wide operating ranges.

Optimal steam process drive sizing is crucial for efficient and sustainable operation of energy-intense industries. Recent years have brought several methods assessing this problem, which differ in complexity and user-friendliness. In this paper, a novel complex method was developed and presented and its superiority over other approaches was documented on an industrial case study. Both the process-side and steam-side characteristics were analyzed to obtain correct model input data: Driven equipment performance and efficiency maps were considered, off-design and seasonal operation was studied, and steam network topology was included. Operational data processing and sizing calculations were performed in a linked MATLAB®−Aspen Plus® environment, exploiting the strong sides of both software tools. The case study aimed to replace a condensing steam turbine by a backpressure one, revealing that: 1. Simpler methods neglecting frictional pressure losses and off-design turbine operation efficie... [more]

Supercritical CO2 power cycles have been deeply investigated in recent years. However, their potential in waste heat recovery is still largely unexplored. This paper presents a critical review of engineering background, technical challenges, and current advances of the s-CO2 cycle for waste heat recovery. Firstly, common barriers for the further promotion of waste heat recovery technology are discussed. Afterwards, the technical advantages of the s-CO2 cycle in solving the abovementioned problems are outlined by comparing several state-of-the-art thermodynamic cycles. On this basis, current research results in this field are reviewed for three main applications, namely the fuel cell, internal combustion engine, and gas turbine. For low temperature applications, the transcritical CO2 cycles can compete with other existing technologies, while supercritical CO2 cycles are more attractive for medium- and high temperature sources to replace steam Rankine cycles. Moreover, simple and regener... [more]

Melt electrohydrodynamic processes, in conjunction with a moveable collector, have promising engineered tissue applications. However, the residual charges within the fibers deteriorate its printing fidelity. To clarify the mechanism through which the residual charges play roles and exclude the confounding effects of collector movement, a stationary printing mode is adopted in which fibers deposit on a stationary collector. Effects of process parameters on generalizable printing outcomes are studied herein. The fiber deposit bears a unique shape signature typified by a central cone surrounded by an outer ring and is characterized by a ratio of its height and base diameter Hdep/Ddep. Results indicate Hdep/Ddep increases with collector temperature and decreases slightly with voltage. Moreover, the steady-state dynamic jet deposition process is recorded and analyzed at different collector temperatures. A charge-based polarization mechanism describing the effect of collector temperature on... [more]

To reveal quality change rules and establish the predicting model of konjac vacuum drying, a response surface methodology was adopted to optimize and analyze the vacuum drying process, while an artificial neural network (ANN) was applied to model the drying process and compare with the response surface methodology (RSM) model. The different material thickness (MT) of konjac samples (2, 4 and 6mm) were dehydrated at temperatures (DT) of 50, 60 and 70 °C with vacuum degrees (DV) of 0.04, 0.05 and 0.06 MPa, followed by Box−Behnken design. Dehydrated samples were analyzed for drying time (t), konjac glucomannan content (KGM) and whiteness index (WI). The results showed that the DT and MT should be, respectively, under 60 °C and 4 mm for quality and efficiency purposes. Optimal conditions were found to be: DT of 60.34 °C; DV of 0.06 MPa and MT of 2 mm, and the corresponding responses t, KGM and WI were 5 h, 61.96% and 82, respectively. Moreover, a 3-10-3 ANN model was established to compare... [more]

Freeze-drying has always been considered an extremely expensive procedure to dehydrate food or pharmaceutical products, and for this reason, it has been employed only if strictly necessary or when the high added value of the final product could justify the costs. However, little effort has been made to analyze the factors that make this technology so unaffordable. In this work, a model was proposed to calculate in detail the operational (OC) and capital costs (CC) of a freeze-drying cycle and an evaluation of the process bottlenecks was made. The main result is that the process itself, contrary to the classic belief, is not the most expensive part of freeze-drying, while the initial investment is the real limiting factor. Under this consideration, the optimization of a freeze-drying cycle should be formulated in order to fit more cycles in the lifespan of the apparatus, instead of merely reducing the power consumption of the machine.

In recent times, optimization began to be popular in the turbomachinery field. The development of computational fluid dynamics (CFD) analysis and optimization technology provides the opportunity to maximize the performance of hydro turbines. The optimization techniques are focused mainly on the rotating components (runner and guide vane) of the hydro turbines. Meanwhile, fixed flow passages (stay vane, casing, and draft tube) are essential parts for the proper flow uniformity in the hydro turbines. The suppression of flow instabilities in the fixed flow passages is an inevitable process to ensure the power plant safety by the reduction of vortex-induced vibration and pressure pulsation in the hydro turbines. In this study, a CFD-based shape design optimization process is proposed with response surface methodology (RSM) to improve the flow uniformity in the fixed flow passages of a Francis hydro turbine model. The internal flow behaviors were compared between the initial and optimal sha... [more]

Thermochemical processes based on sulfur compounds are among the most developed systems to produce hydrogen through water splitting. Due to their operating conditions, sulfur cycles are suited to be coupled with either nuclear or solar plants for renewable hydrogen production. A critical review of the most promising sulfur cycles, namely the Hybrid Sulfur, the Sulfur Iodine, the Sulfur Bromine and the Sulfur Ammonia processes, is given, including the work being performed for each cycle and discussing their maturity and performance for nuclear and solar applications. Each sulfur-based process is comprised of a sulfuric acid thermal section, where sulfuric acid is concentrated and decomposed to sulfur dioxide, water and oxygen, which is then separated from the other products and extracted. A critical review of the main solutions adopted for the H2SO4 thermal section, including reactor configurations, catalytic formulations, constitutive materials and chemical process configurations, is p... [more]

For the simulation of a trickle-bed reactor (TBR) in coal and oil refining, modeling the liquid maldistribution of the gas-liquid distributor incurs enormous pre-processing work and bears a huge computational cost. A closed-loop optimized system with computational fluid dynamic (CFD) data is therefore proposed for the first time in this paper. A fast prediction model based on support vector regression (SVR) is developed to simplify the modeling of the liquid flow rate in TBRs. The model uses CFD simulation results to determine an optimized set of structural parameters for the gas-liquid distributor in TBRs. In order to obtain an accurate SVR model quickly, the particle swarm optimization (PSO) algorithm is employed to optimize the SVR parameters. Then, the structural parameters corresponding to the minimum liquid maldistribution factor are calculated using the response surface methodology (RSM) based on the hybrid PSO-SVR model. The CFD validation results show a good agreement with the... [more]

Biomass gasification is nowadays considered a viable option for clean energy production. Furthermore, still more efforts need to be spent to make this technology fully available at commercial scale. Drawbacks that greatly limit the full-time plant availability—and so its economically feasibility—mainly concerns syngas purification by contaminants such as tars. Different technological approaches were investigated over last two decades with the aim to increase both the plant availability and the overall efficiency by keeping, at the same time, CAPEX and OPEX low. Among technologies, fluidized beds are surely the most promising architectures for power production at thermal scale above 1 MWth. Gasifier can be surely considered the key component of the whole power plant and its proper design, the main engineering effort. This process involves different engineering aspects: thermo-structural, heat, and mass transfer, and chemical and fluid-dynamic concerns being the most important. In this s... [more]

Results from an investigation of the mechanical size reduction with the Szego Mill™ as a pretreatment method for lignocellulosic biomass are presented. Pretreatment is a highly expensive and energy-consuming step in lignocellulosic biomass processing. Therefore, it is vital to study and optimize different pretreatment methods to find a most efficient production process. The biomass was milled with the Szego Mill™ using three different approaches: dry milling, wet milling and for the first time nitrogen assisted wet milling was tested. Bioethanol and biogas production were studied, but also fibre analysis and SEM (scanning electron microscope) analysis were carried out to characterize the effect of different milling approaches. In addition, two different process flows were used to evaluate the efficiency of downstream processing steps. The results show that pretreatment of barely straw with the Szego Mill™ enabled obtaining glucose concentrations of up to 7 g L−1 in the hydrolysis mixtu... [more]

Biotechnological processes involving the presence of microorganisms are realized by using various types of stirred tanks or laboratory-scale dual-impeller commercial bioreactor. Hydrodynamics and mass transfer rate are crucial parameters describing the functionality and efficiency of bioreactors. Both parameters strictly depend on mixing applied during bioprocesses conducted in bioreactors. Establishing optimum hydrodynamics conditions for the realized process with microorganisms maximizes the yield of desired products. Therefore, our main objective was to analyze and define the main operational hydrodynamic parameters (including flow field, power consumption, mixing time, and mixing energy) and mass transfer process (in this case, gas−liquid transfer) of two different commercial bioreactors (BioFlo® 115 and BioFlo® 415). The obtained results are allowed using mathematical relationships to describe the analyzed processes that can be used to predict the mixing process and mass transfer... [more]