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The problem of process wastewater arises not only in fine chemical industry, but also where water is used for washing. In these cases, surfactant material is given to the water, so its washing capability is enhanced. The used water contains surfactant material and dirt. It has high chemical oxygen demand (COD) resulting in serious environmental problems. Finding a solution is inevitable because of the high wastewater fine which has to be paid by the factories if wastewater is emitted without any treatment. A suitable method had to be found that follows the principles of circular economy, so the industrial cycles can be closed like in nature and the water can be reused. Our designed method focuses on different kinds of wastewater containing special surfactant materials, and it has chemical industry relations. The treatment should have reduced the high COD value below to 1000 mgO2/L, which is the discharge limit. It was also aimed that instead of discharging, the treated water could be recycled and reused. Our new physicochemical treatment process consists of a vacuum evaporation method that reduces COD from c.a. 8400 to 1100 mgO2/L. Both laboratory and pilot experiments were investigated. Since this COD value was not satisfactory, a subsequent reverse osmosis membrane operation was also applied. This two-step method, vacuum evaporator followed by reverse osmosis, was able to reduce the COD in wastewater containing surfactant/washing material below the discharge limit. 100 mgO2/L could be reached with using TriSep™ X201 membrane. Penalty calculation and cost estimation also demonstrate the efficiency of our novel method.

In the course of the present study, the pervaporative dehydration of two ternary mixtures: ethanol/n-butanol/water and ethanol/ethyl acetate/water were investigated through hydrophilic polymer composite PERVAP 1210 membrane. The effects of temperature and the concentrations of water and organic components on permeation were studied through pervaporation experiments. The influence of Hansen solubility parameters of the components and mixtures on their permeation was also examined. It has been found that changes of organic ratios in the feed solution affect organic permeation due to mutual interactions and flux coupling. This interaction was built in a suggested semi-empirical mass-transport model for ternary mixtures with optional simplifications. The modeled partial fluxes are in good accordance with the measured values.

Thermal crosslinked double-network poly (vinyl alcohol) (PVA) is prepared by applying the sequential method. The obtained membrane is characterized by thermogravimetric analysis (TGA), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and contact angle analyses. It is concluded from FTIR analysis, contact angle measurements and measuring of swelling degree at different feed concentrations that the interpenetrating of the second network, that is the double network (DN), decreases the hydrophilicity of the membrane, while improving the thermal behavior and stability under high temperature. For the sake of the comparison of PVA and DN-PVAs selectivity, total permeation flux, individual fluxes and pervaporation separation index are evaluated for the dehydration of ethanol solution with a feed composition of 85/15 wt% ethanol/water solution at 40–60 °C. Furthermore, the effect of feed temperature on the permeation flux is expressed by the Arrhenius relationship. The performance of DN-PVAs membrane is appraised according to the change in feed concentration and operating temperature. The ethanol concentration in the feed is 75–95 wt% the DN-PVAs has flux values in the range of 41–414 g/m2 h and separation factor of 105–376 at the operating temperature 40–60 °C.

The work is motivated by an industrial problem, which is alcohol removal from pharmaceutical process wastewater. The aim of the study was to develop a complete hybrid operation is investigated. Ethanol dehydration, in combination with distillation and hydrophilic pervaporation, is used to investigate about the extent of separation of the ethanol-water mixture. The aim of this research is to rigorously model and optimize this hybrid operation in professional flowsheet simulator environment. The number of minimal theoretical plates of distillation column and minimal effective membrane transfer area are determined. Cost estimation is also examined according to Douglas methodology. Considering our results it can be concluded that, the distillation and hydrophilic pervaporation processes are suitable for separation ethanol and water in 99.5 weight percent purity

Chemical process design is a creative step of engineers that should be supported by different computer-aided design tools. Such tools should be simple and easy to use because process synthesis often means the investigation of a huge number of alternatives. During the design of the separation of liquid mixtures, among many others, distillation and pervaporation are usually simultaneously considered because pervaporation is frequently considered as an alternative to distillation. To easily compare the efficiencies of continuous pervaporation and flash distillation, we propose a new and simple method, the so-called membrane flash index (MFLI). The comparison is based upon vapor–liquid equilibrium data and the permeation data of a pervaporation membrane and therefore can be plotted on a common chart in the case of binary mixtures. The permeation values of organophilic and hydrophilic pervaporations can be calculated with the help of known separation factors and feed concentrations. The MFLI is dimensionless a...

Washing detergents in process wastewaters from fine chemical industry produce high Chemical Oxygen Demand (COD), which poses a serious environmental problem. Method has to be found, which follows the principles of circular economy so that the treated water can be recycled or reused. Heat pump vacuum evaporator is evaluated in order to reduce the Chemical Oxygen Demand of process wastewater with washing detergent content from initial 7500 mg O2/L to a lower value below the effluent limit , which is 1000 mg O2/L. Yield and COD rejection are determined for the evaluation of selected treatment. Experiments are investigated with LED Italia R150-v3 pilot apparatus. Different evaporation pressures were applied during measurements. It The highest removal or reduction of in the Chemical Oxygen Demand was reached certainly using the lowest possible pressure, which is 40 mbar.

The work is motivated by a separation problem, which is ethanol removal from aqueous mixtures with membranes. Ethanol can be considered as promising biomass based platform molecule. The platform molecule includes several building-block chemicals grouped together, resulting in a range of downstream chemical products. To solve the target, organophilic pervaporation system is investigated using benchmarked Sulzer PERVAP™ 4060 membranes. Separation factors, total permeation fluxes, permeances and selectivities are experimentally determined. The target of this work is to parameter estimation for semi-empirical pervaporation model. The measured data are evaluated with improved pervaporation model by Valentinyi et al. [1]. Three different polymeric flat sheet membranes are investigated, PERVAP™ 4060, PERVAP™ 1060 and CELFA-CMG-OG010. It is found that the model can be applied also for each organophilic separation case.

Biodiesel production showed an immense increase worldwide in the past decade. Since the comprehensive analyses of biodiesel production processes and their comparative evaluation are both rare and not informative enough, e.g., for scientists and decision makers, in this work different, favored biodiesel production alternatives (rapeseed, soybean and palm) are analyzed from multiple viewpoints and compared. A complex examination is carried out with Political, Economic, Social, Technological, Legal and Environmental (PESTLE) analysis, where cradle-to-grave life cycle analysis is incorporated and performed within PESTLE factors. Life cycle inventory is set up based on Ecoinvent 3.3 database, while life cycle impact assessments are achieved by IPCC 2013, IMPACT 2002+, EPS 2000 and 2015dx methods. Monte Carlo analysis is also carried out in order to make certain about the robustness of input data. The investigated factors are weighted and ranked with multi-criteria decision analysis, wherein Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) method is applied for the comparison of alternatives. Our work presents a clear methodology for the comprehensive evaluation of biodiesel production alternatives, but the guideline can be followed for the evaluation of other production alternatives. In spite that the life cycle analysis shows the palm oil as the best alternative, the results of our comprehensive analysis show that the highest overall TOPSIS score can be achieved with rapeseed-based biodiesel pathway, especially for the European region.

This study continues our research about dividing-wall distillation columns (DWCs) with upper and lower partitions (Ind. Eng. Chem. Res. 2016, 56, 952). Thermodynamic efficiencies and heat demands are investigated to offer a more complex point of view about distillation technologies. Rigorous simulations of nine distillation systems are completed, and the results are evaluated. Among the separation systems there are conventional direct and indirect distillation systems and energy-integrated ones, that is, DWCs with upper and lower partition, columns with side stripper or side rectifier, the fully thermally coupled distillation column, the sloppy system, and a direct sequence with backward heat integration are examined using three different alcohol mixtures. Results are obtained from rigorous simulations using exergy analysis. Thermodynamic efficiencies are in agreement with the expectations based on previous researches. On the basis of the thermodynamic efficiencies and heat demands the direct sequence wit...

Microalgae-based biorefineries for the production of renewable biofuels like biodiesel, upgraded bio-oil, biochar, biogas and other high-value chemicals have received great attention in recent decades as potential major sources of energy for the future. Microalgae are a suitable species to produce biodiesel and other high energy density by-products; however, it is questionable whether a net energy gain can be realized or not considering the whole processing chain. In the present study, the energy balances of different algae-based biofuel and bioenergy production technologies are investigated in detail and compared to each other corresponding to a cradle-to-grave overall energetic analysis. The study includes cultivation, harvesting, cell pretreatments (cell disruption, drying, grinding), lipid extraction, transesterification, gasification and hydrothermal liquefaction with bio-oil stabilization and hydroprocessing. The energy consumption and energy gain are estimated for each operational step to determine the net energy ratio (NER, energy output over energy input) for the overall technologies studied. Our detailed investigation enables to detect the most energy consuming unit operation, that is, the bottleneck point(s) of the microalgae-based technologies which should be still improved in the future for the sake of more efficient algae-based biorefineries. The investigation makes also possible to evaluate and compare the different large scale alternatives for biomass transformation. Positive energy balances with a NER value of 1.109 and 1.137 are found in two already existing processes: open raceway ponds and closed photobioreactors, respectively. Our work gives also a detailed algorithm that can be followed at the evaluation of other microalgae-based biorefineries.

The work is motivated by an industrial environmental problem, which is ethanol removal from aqueous mixture. To complete this goal organophilic pervaporation of ethanol/water mixture through commercially available Sulzer PERVAP™ 4060 is investigated to obtain information about the removal of ethanol. The experimental results are obtained at different feed ethanol concentrations and temperatures. Our experimental data are evaluated with the semi-empirical pervaporation model (Valentinyi et al. 2013) of our improvement and it is found that the model can be applied also for this organophilic case. Linear and quadratic surfaces suiting (Model III) are also investigated in order to estimate partial permeate flux. The results of parameter estimation and modelling of the pervaporation show that the novel model that considers the concentration dependency of the transport coefficient (Model II) is also capable for the modelling of organophilic pervaporation and results in a better fit to the experimental data, than basic pervaporation model (Model I) and Model III.

Pervaporation is proved to be a commercially viable membrane separation process by this time. However, to become a widely applied process in the industry it is of crucial importance to develop membrane properties, process and module design as well as proper modelling in professional software environment. In this work a pervaporation model improvement of the basic solution–diffusion model ( Rautenbach et al., 1990 ) is recommended and tested on experimental data. The reason behind this improvement is that the transport coefficient cannot be considered as constant assumed in the basic model in a wide concentration range. The change of the transport coefficient is considered as an exponential function of the composition of permeating compound. This exponential dependency is assumed by the authors after investigating the shape of the flux curves measured in a wider feed concentration range. The accuracy of this improved model is experimentally tested with the pervaporation of isobutanol–water, n-butanol–water, and ethanol–water mixtures on commercial hydrophilic composite membranes. This model improvement gives accurate and reliable data for a wide range of feed concentration proving that the assumption of practically constant transport coefficient cannot be applied. Therefore the use of this improved model in professional flowsheeting software packages is more reliable and reasonable than the application of the basic model for the design and operation of pervaporation, or a more effective hybrid separation system including pervaporation.

The industrial application of pervaporation as a membrane separation technology is increasing caused by the numerous advantages of this method. However, to complete engineering design, like in the cases of distillation, azeotropic distillation and absorption, reliable and adequate modelling of the process in flowsheeting environment is indispensable. A proper model is especially needed if the more complicated but more economical and environmentally sound hybrid separation methods are designed or investigated.In this study two pervaporation models, the solution-diffusion model of Rautenbach [1] and its developed form [2], are compared and evaluated with computer simulation on the dehydration processes of isobutanol-water and ethanol-water mixtures. Simulations of a hybrid separation method containing pervaporation for the separation of these mixtures are performed, thus proving the importance of using a proper pervaporation model regarding the discrepancies caused by the application of a false model.