Andras Jozsef Toth

Separation of Process Wastewater with Extractive Heterogeneous-Azeotropic Distillation

Abstract The application of vapour-liquid equilibria-based separation alternatives can be extraordinarily complicated for the treatment of process wastewaters containing heterogeneous-azeotropic. Despite dissimilar successfully tested methods for separation, there is possibility to get better distillation method by enabling the separation of more and more specific process wastewater. Extractive heterogeneous-azeotropic distillation (EHAD) is a new advance in treatment of fine chemical wastewater showing special features to cope with the treatment of highly non-ideal mixtures. This method combines the worth of heterogeneous-azeotropic and extractive distillations in one apparatus without addition of any extra materials. The study of the separations of ternary component process wastewater from the fine chemical industry shows both in the modelled and experimental results that EHAD can be successfully applied. The measured and modelled compositions at extreme purities, that is, close to 0% or 100%, can be different because of the inaccuracies of the modelling. This highlights the paramount importance of the experiments if special extra-fine chemicals with almost no impurities, e.g. of pharmacopoeial quality are to be produced by special distillation technique. This study expands the application of EHAD technique, this new field is the separation of process wastewaters.

Evaluation of the accuracy of modelling the separation of highly non-ideal mixtures: extractive heterogeneous-azeotropic distillation

Abstract The distillation based separation can be extremely complex if highly non-ideal mixtures are to be separated. In spite of different successfully applied unit operations there is still possibility to improve distillation technique and widen its toolbar. A new improvement in this area is the introduction of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of the extractive and heterogeneous-azeotropic distillations in one unit without an extra material addition. In spite of the complexity of this unit operation it can be efficiently applied and complex separation technologies can be simplified with its application. The separations of ternary and quaternary mixtures from the fine chemical industry show both in the modelled and the experimental results that the extractive heterogeneous-azeotropic distillation is an efficient tool of this area. Demonstrating the accuracy of EHAD, the separation of methanol–ethyl-acetate–water and ethanol–ethyl-acetate–water mixtures are examined and the EHAD is compared with conventional distillation techniques. These separation processes are rigorously modelled and optimized with dynamic optimization method in professional flowsheeting environment. The objective function is the total annual cost but the energy consumption is also investigated. The modelling results are verified with laboratory experiments, too. It can be concluded that the extractive heterogeneous-distillation is a capable method for the separation of these highly non-ideal mixtures.

Enhanced separation of highly non-ideal mixtures with extractive heterogeneous-azeotropic distillation

ABSTRACT The distillation based separation can be extremely complex if highly non-ideal mixtures are to be separated. In spite of different successfully applied unit operations there is still a possible way to improve the distillation technique and widen its toolbar. A new improvement in this area is the development of the extractive heterogeneous-azeotropic distillation (EHAD). This unit operation includes the merits of extractive- and heterogeneous-azeotropic distillations in one unit without extra material addition. Our work supports EHAD features with successful experiments compared with modelling and comparison with other separation structures proving that the application of EHAD makes the separation of extremely non-ideal mixtures possible on an easy, powerful, energy saving, and cost efficient way.

Comparison of air and steam stripping: removal of organic halogen compounds from process wastewaters

AbstractnIn the engineering practice, there are two basic alternatives of physicochemical treatment for the removal of volatile compounds from process wastewaters: stripping with air or stripping with steam. In this work, these alternatives are investigated and compared in the case of a real industrial problem that is typical for the fine chemical industry and general conclusion is drawn. The removal of the organically bound halogens, called adsorbable organically bound halogens, is investigated. The two alternatives, air and steam stripping, are first modeled in the professional software environment of ASPEN Plus®. The model is validated on the data of an existing air stripper for the removal of organic halogens. Same organic halogens removal is applied for the design of a steam stripper. It is proved that the steam stripping shows better operability and economic performance than the air stripping; moreover, the volatile and/or adsorbable organically bound halogen compounds can be recovered in the distillate and they can be reused improving the sustainability.

Modelling of organophilic pervaporation to compete with distillation

Abstract In the case of process design a new graphical representation method is proposed on the basis of computer modelling of distillation and pervaporation. The new method relies on also vapour-liquid equilibrium data. The comparison can be performed on a common y-x equilibrium diagram of the mixture to be separated. In our work methanol-water, ethanol-water and isobutanol-water are the investigated systems. The alcohol permeate composition values are plotted over the feed composition. Permeate alcohol concentrations are calculated with the help of known separation factors and feed alcohol concentrations. The corresponding vapour-liquid equilibrium composition is also shown so that pervaporation and flash distillation could be compared. In the case of methanol and ethanol separation a lower separation capability of the different PDMS membrane is detected than a flash distillation. In the case of isobutanol-water mixture every calculated isobutanol permeate weight fractions of different organophilic membranes are above the equilibrium vapour concentration. The proposed graphical representation method visualizes the feasible operation ranges of distillation and pervaporation. It enables also the designing engineer for the proper selection of the separation method.

Complex whey utilization: the propionic acid alternative

Abstract Whey is the complex waste of the dairy industry. Despite the fact, that it has numerous applications (like different form of food supplements), its major amount is still handled as waste. The carbohydrate, protein and lactic acid content, as well as the COD and BOD, are sufficiently high warranting disposal as waste resulting in high costs; however, their levels are insufficient for the cost-effective isolation and purification. Most of the numerous reports on whey utilisation focus on lactose utilization, while lactic acid removal is complex, but necessary, particularly in case of sour whey decontamination. According to our best knowledge among the microbial fermentation, the only lactic acid (as carbon source) utilization process is propionic acid fermentation. Propionic acid is an attractive product with a wide application range. In this study, two propionic acid producing microorganisms were investigated in terms of industrial applicability. The propionic acid producing bacteria are generally characterized by anaerobic metabolism (except the pathogenic P. acne); but, for application in a biorefinery, facultative anaerobe behavior is the most appropriate and cost-effective. In this study, the aero-tolerances of Propionibacterium freudenreichii subsp. shermanii and Propionibacterium acidipropionici were examined; their propionic acid-producing properties (yield, concentration, substrate preference, productivity) were compared.

Lactic acid production from cane molasses

Abstract Molasses, a by-product of the sugar manufacturing process, generally comprises approximately 50% (w/w) of total sugars, but it is currently used primarily [1] as an animal feed and as a raw material in alcohol production. Currently, the sugar production is more than 160 million tones worldwide. Its byproduct molasses contain heavy metals which have growthinhibitory effect. The main sugar content in molasses is sucrose which often need to be hydrolyzed to glucose and fructose especially for utilization by Lactobacillus species. Lactobacillus species can convert sugar content to lactic acid with great efficiency, which is a valuable chemical. Lactic acid production from sugar molasses using batch fermentations with Lactobacillus casei and Lactobacillus sp. MKT878 were investigated in this study. Results showed, that both examined Lactobacillus species could grow on molasses despite the heavy metals inhibitory effects. The conversion of sugar content to lactic acid was successful with yield between 55-80 g/g.