Scale-up Procedure Research Articles

Optimization and upscaling of the supercritical carbon dioxide extraction of Solidago gigantea Ait. of an industrial relevance

The main aim of this study was to investigate the possibility of using Solidago gigantea Ait., as a source of fatty acids. S. gigantea, by contrast to rapeseed or sunflower seeds, is not commonly used plant material to obtain these compounds. For that purpose, the proper optimization of supercritical carbon dioxide extraction (SFE-scCO2) of S. gigantea at quarter-technical plant was investigated to provide the highest concentration of FAME. SFE-scCO2 is a green technology and it is very efficient technique for the extraction of non-polar compounds. Response surface methodology (RSM) was used to analyze and evaluate the influence of chosen input variables: pressure (P, MPa), temperature (T, K) and solvent flow rate (F, kg h−1) on FAME content in products. The output variable in the obtained extract was determined by GC–MS. The optimal parameters obtained at quarter-technical plant were T =313.79 K (40.64 °C), P = 22.22 MPa and F =6.46 kg h−1. Finally, the scale-up procedure of optimal conditions from the quarter-technical to half-technical plant was conducted to substantiate the correctness of the optimization process and to facilitate the transfer of the process to industry scale. Scale-up procedure of optimal conditions was conducted according to various criteria and it ended successfully. Extraction with constant ratio of solvent mass to mass of the batch (S CO2/M, kg kg−1) with the final result with confidence interval: 273.22 mg g−1 DM proved the correctness of the optimization proces. The obtained amount of FAME concentrations allowed to conclude that S. gigantea can be considered as a source of fatty acids. Finally, obtained optimal parameters can be implemented in an industry plant.

Adsorptive removal of Cr(VI) from aqueous solution: kinetic, isotherm, thermodynamics, toxicity, scale-up design, and GA modeling

Chromium (VI) is a well-known toxic, industrial, water pollutant which has various, adverse effects on environmental health. Utilization of agricultural waste in effluent water treatment would minimize the problem of water pollution. The present study deals with the use of three types of nut shells for Cr(VI) removal. Adsorbents are characterized, using point of zero charges (pHpzc), FTIR, BET surface area analysis, and SEM. The variation of different operating parameters on metal removal was conducted. The best sorption kinetic model was pseudo-second order. The adsorption process is both physical and chemical, and this depends on temperature. The Cr(VI) adsorption is spontaneous and endothermic. According to isotherm studies, Langmuir isotherm model fits fairly well for all adsorbents. Regeneration studies suggest that the adsorbents have proper regeneration criteria and can be used for multiple times. Study on RBC count of Gallus gallus domesticus gives concrete evidence of deadly effects of Cr(VI). It also figures out that the effluent solution treated with bio-adsorbents is less harmful. The scale-up design procedure is reported here. This study proved that groundnut shell, walnut shell, and almond shell have immense potential and can be utilized even after regeneration as replacement of commercial adsorbents for industrial wastewater. GA–ANN modeling has been developed for the best possible wastewater treatment management.

Design and optimization of an electrocoagulation reactor for fluoride remediation in underground water sources for human consumption

Fluoride remediation in underground waters of volcanic origin was performed at laboratory scale using an electrocoagulation (EC) technique. The natural waters from certain volcanic springs on the island of Tenerife (Canary Islands, Spain) contain average fluoride concentrations in excess of 7 mg/L. Thus, it is necessary to treat the water for fluoride mitigation below the maximum acceptable concentration of 1.5 mg/L according to Spanish regulations for drinking water. The design and optimization of a sustainable process was accomplished using a progressive scale-up procedure involving three pilot reactors with different configurations and effective working volumes. A bipolar electrode cell design using aluminum electrodes was used in all cases. The good performance of the process was confirmed by reducing the fluoride concentration from 7.35 to 1.4 mg/L. The following optimized operating conditions were determined for a continuous flow cell system: current density, 10 mA/cm2; residence time, 10 min; and, half-period of polarity reversal, 1 min. Furthermore, the kinetics of the remediation process can be fitted using the Variable Order Kinetic (VOK) model, with a power relationship between fluoride concentration and residence time in the EC reactor.

Biotransformation of mogrosides from Siraitia grosvenorii by Ganoderma lucidum mycelium and the purification of mogroside III E by macroporous resins

Mogrosides are the major triterpenoidal saponins found in swingle, the fruit of Siraitia grosvenorii, which have recently been widely used throughout the world as natural food sweeteners. Among this class of compounds, mogroside III E (MG III E) exhibits the most intense sweetness, and it was also found to effectively regulate blood glucose levels. However, the relative abundance of naturally occurring MG III E is low compared to other mogrosides. Therefore, the purpose of this study was to enrich MG III E through biotransformation of fruit extracts and to develop a reliable method for its purification. We used HPLC coupled with mass spectrometry and nuclear magnetic resonance spectroscopy for metabolite analysis and identified MG III E as a major metabolite of Ganoderma lucidum mycelium. This organism converts the most abundant mogroside, mogroside V, to MG III E via a deglycosylation reaction; high levels of β-glucosidase activities were also detected. In addition, we established an efficient purification method for MG III E using HP-20 macroporous resin. Optimization of the method was accomplished by kinetic model fitting, dynamic adsorption studies, and desorption experiments. The purity of MG III E was increased from 11.71% to 54.19%, with a 70%–76% recovery rate, and the scaled-up purification process allowed us to harvest 17.38 g of MG III E with 55.14% purity and a 74.71% of recovery rate. Therefore, our low cost, time-saving, easy to scale-up procedure for isolating MG III E could be applicable in industrial processes.

Produced Flowback Salts vs. Induced-Fracture Interface: A Field and Laboratory Study

Summary The water recovered from hydraulic-fracturing operations (i.e., flowback water) is highly saline, and can be analyzed for reservoir characterization. Past studies measured ion-concentration data during imbibition experiments to explain the production of saline flowback water. However, the reported laboratory data of ion concentration are approximately three orders of magnitude lower than those reported in the field. It has been hypothesized that the significant surface area created by hydraulic-fracturing operations is one of the primary reasons for the highly saline flowback water. In this study, we investigate shale/water interactions by measuring the mass of total ion produced (TIP) during water-imbibition experiments. We conduct two sets of imbibition experiments at low-temperature/low-pressure (LT/LP) and high-temperature and high-pressure (HT/HP) conditions. We study the effects of rock surface area (As), temperature, and pressure on TIP during imbibition experiments. Laboratory results indicate that pressure does not have a significant effect on TIP, whereas increasing As and temperature both increase TIP. We use the flowback-chemical data and the laboratory data of ion concentration to estimate the fracture surface area (Af) for two wells completed in the Horn River Basin (HRB), Canada. For both wells, the estimated Af values from LT/LP and HT/HP test results have similar orders of magnitude (approximately 5.0×106 m2) compared with those calculated from production and flowback rate-transient analysis (RTA) (approximately 106 m2). The proposed scaleup procedure can be used as an alternative approach for a quick estimation of Af using early-flowback chemical data.

Nitrifying Soil Bacterium Nitrosomonas europaea: Operational Improvement of Standard Culture Medium

Nitrosomonas europaea is the most extensively studied ammonia-oxidizing bacterium (AOB), being a ubiquitous player in the conversion of ammonia in the soil environment. The precipitation of constituents of the standard culture medium, American Type Culture Collection (ATCC) #2265, further hinders both the study of N. europaea vital role in the nitrogen cycle and the development of biotechnological applications, as the presence of inorganic debris severely compromises scale-up procedures and downstream processing. The standard formulation was analyzed; the precipitate was identified as being struvite. Struvite is spontaneously formed when magnesium, phosphate, and ammonium are available in a high pH solution. This combination is common and transversal to a series of AOB media formulations. Therefore, a non-precipitating medium was developed. The modified medium does not require filter sterilization, which reduces 99% of its production cost. The kinetic performance of N. europaea was evaluated in the standard and modified medium. A precise and direct quantification of the bacterium cell growth profile was achieved using fluorescent in situ hybridization (FISH) and flow cytometry, which was correlated with other metabolic parameters. The performance of N. europaea was not impaired in the modified medium.

A large-scale experimental comparison of batch and continuous technologies in pharmaceutical tablet manufacturing using ethenzamide

This paper compares batch and continuous technologies in terms of product quality and process performance in pharmaceutical tablet manufacturing using ethenzamide as the active pharmaceutical ingredient. Batch and continuous processes using wet granulation were investigated by performing experiments on the scale of 5 and up to 100 kg/lot, using the same raw materials. Three technologies were tested and compared: (i) batch technology using fluidized bed granulation, (ii) batch technology using high shear granulation, (iii) continuous technology using high shear granulation. In the full-scale experiment, in all three technologies including continuous technology, the quality of the tablets fulfilled the target values regarding hardness, active pharmaceutical ingredient content, and dissolution. The granules produced by different technologies, however, presented varying attributes regarding granule size distribution, loose bulk density, or scanning electron microscope images. The process performance, more specifically the yield, was slightly better for batch technologies than for the continuous technology, mainly due to losses in the start-up operation. Notably, this study has shown that continuous technology, which is generally believed to not entail scale-up procedures, could in fact, require parameter adjustment for prolonged operation. The results provided suggestions for improvements to implement large-scale continuous technologies in the pharmaceutical industry.

Critical review of different aspects of liquid-solid mixing operations

Abstract Mechanically stirred slurry tanks are utilized in several industries to perform various unit operations such as crystallization, adsorption, ion-exchange, suspensions polymerization, dispersion of solid particles, leaching and dissolution, and activated sludge processes. The major goal of this review paper is to critically and thoroughly analyse the different aspects of previous research works reported in the literature in the field of liquid-solid mixing. This paper sheds light on the advantages and limitations of various particle concentration measurement methods employed to assess the suspension quality and the extent of solid suspensions in slurry reactors. Attempts are being made to identify and compare various mathematical models and methods to quantify particle dispersion and distribution in slurry reactors. It has been shown that various factors such as geometric configurations, agitation conditions, and physical characteristics of liquid and solid have pronounced influence on local suspension quality and power consumption. Computational fluid dynamics (CFD) modeling can be extremely useful in assessing the suspension of solid particles in slurry tanks. A critical review of different scale-up procedures employed for solid suspension and distribution in liquid-solid systems is presented as well. The findings of this review paper can be useful for future research works in liquid-solid mixing.

Adding a dimension to cell fate.

Cell fate specification, gene expression and spatial restriction are process finely tuned by epigenetic regulatory mechanisms. At the same time, mechanical forces have been shown to be crucial to drive cell plasticity and boost differentiation. Indeed, several studies have demonstrated that transitions along different specification states are strongly influenced by 3D rearrangement and mechanical properties of the surrounding microenvironment, that can modulate both cell potency and differentiation, through the activation of specific mechanosensing-related pathways. An overview of small molecule ability to modulate cell plasticity and define cell fate is here presented and results, showing the possibility to erase the epigenetic signature of adult dermal fibroblasts and convert them into insulin-producing cells (EpiCC) are described. The beneficial effects exerted on such processes, when cells are homed on an adequate substrate, that shows “in vivo” tissue-like stiffness are also discussed and the contribution of the Hippo signalling mechano-transduction pathway as one of the mechanisms involved is examined. In addition, results obtained using a genetically modified fibroblast cell line, expressing the enhanced green fluorescent protein (eGFP) under the control of the porcine insulin gene (INS) promoter (INS-eGFP transgenic pigs), are reported. This model offers the advantage to monitor the progression of cell conversion in real time mode. All these observations have a main role in order to allow a swift scale-up culture procedure, essential for cell therapy and tissue engineering applied to human regenerative medicine, and fundamental to ensure an efficient translation process from the results obtained at the laboratory bench to the patient bedside. Moreover, the creation of reliable in vitro model represents a key point to ensure the development of more physiological models that, in turn, may reduce the number of animals used, implementing non-invasive investigations and animal welfare and protection.

Scale-Up Procedure for Primary Drying Process in Lyophilizer by Using the Vial Heat Transfer and the Drying Resistance.

The objective of this study is to design primary drying conditions in a production lyophilizer based on a pilot lyophilizer. Although the shelf temperature and the chamber pressure need to be designed to maintain the sublimation interface temperature of the formulation below the collapse temperature, it is difficult to utilize a production lyophilizer to optimize cycle parameters for manufacturing. In this report, we assumed that the water vapor transfer resistance (Rp) in the pilot lyophilizer can be used in the commercial lyophilizer without any correction, under the condition where both lyophilizers were operated in the high efficiency particulate air (HEPA)-filtrated airflow condition. The shelf temperature and the drying time for the commercial manufacturing were designed based on the maximum Rp value calculated from the pilot lyophilizer (1008 vials) under HEPA-filtrated airflow condition and from the vial heat transfer coefficient of the production lyophilizer (6000 vials). And, the cycle parameters were verified using the production lyophilizer of 60000 vials. It was therefore concluded that the operation of lab- or pilot-scale lyophilizer under HEPA-filtrated airflow condition was one of important factors for the scale-up.

Anisotropic-Wormhole-Network Generation in Carbonate Acidizing and Wormhole-Model Analysis Through Averaged-Continuum Simulations

Summary The optimal design of matrix-acidizing operations in carbonate reservoirs is a discussion in progress. Although several models are available to the industry for predicting wormhole propagation, most of them are not sufficiently practical to be used in real treatment designs, or they were developed to represent coreflood data and cannot be simply scaled up to represent wormhole formation in complex well geometries. This problem is addressed by Furui's wormhole-propagation model (Furui et al. 2012a), which is a modification of the Buijse and Glasbergen (2005) empirical correlation, including a scaleup procedure to represent field carbonate-acidizing operations using laboratory coreflood data. It is a practical engineering tool that can be used for treatment designs in horizontal wells, including barefoot and perforation-cluster completions in fairly isotropic and homogeneous reservoirs. In this work, an analysis of Furui's model is performed, including the effect of anisotropy (x, y, z permeability) in the carbonate reservoir. The analysis includes both radial and elliptical wormhole propagation that forms from an openhole completion, and the spherical or ellipsoidal wormhole propagation that emerges from each perforation in a perforation-cluster completion that makes the use of a limited-entry technique for achieving an acceptable acid placement. The development is made using extensive 3D numerical simulations with a two-scale continuum model and a finite-volume method to represent the dissolution of the porous medium. The numerical model is tuned to represent real results through matching experimental coreflood data and dissolution patterns. Conclusions are obtained regarding both isotropic and anisotropic formations. In isotropic formations with the radial propagation of wormholes, simulations indicate that a number from four to six wormholes propagates radially in each plane. When the propagation is spherical, simulations result in a number from 16 to 24 wormholes, propagating spherically from the point of acid injection. In anisotropic formations, the radial stimulated zone might become an elliptical stimulated zone, depending on the acid-injection rate and the permeability-heterogeneity magnitude. The major axis of the elliptical stimulated zone coincides with the direction of a higher permeability and a longer permeability-correlation length, and it is longer for larger acid-injection rates. In the same manner, the spherical wormhole-propagation pattern might become an ellipsoidal stimulated zone in anisotropic formations.

Upscaling fixed bed adsorption behaviors towards emerging micropollutants in treated natural waters with aging activated carbon: Model development and validation

A scale-up procedure was assessed in this study to predict the fixed bed adsorption behaviors with aging granular activated carbon (GAC) for various micropollutants (pesticides, pharmaceuticals). Two assumptions of this upscaling methodology (i.e., involving equal adsorption capacities and surface diffusivities between the batch test and the fixed bed) were studied for the first time to investigate the aging effect on the adsorption capacity and kinetics of carbon at full scale. This study was conducted in natural waters (the Seine River) treated by Veolia Eau d’Ile de France in Choisy-Le-Roi, a division of Syndicat des Eaux d’Ile de France, aiming to monitor real industrial conditions. The isotherms showed that the adsorption capacity for most compounds was significantly affected by aging. For the mass transfer coefficients (i.e., as determined by the homogeneous surface diffusion model (HSDM)), different patterns of adsorbate/adsorbent behaviors were observed, suggesting different competition mechanisms. The model predictions (i.e., HSDM) performed with all parameters obtained during the batch tests tended to overestimate the full-scale pilot adsorption performance. This overestimation could be compensated for by applying a scaling factor. Finally, an empirical pseudo-first order function was used to model the impact of the GAC service time on the characteristic adsorption parameters. Thus, our scale-up procedure may enable the prediction of long-term fixed bed adsorption behaviors and increase the model efficiency for practical implementation.

A Novel Framework for Integration of Random-Walk Particle-Tracking Simulation in Subsurface Multi-phase Flow Modeling

Coarse-scale models are generally preferred in the numerical simulation of multi-phase flow due to computational constraints. However, capturing the effects of fine-scale heterogeneity on flow and isolating the impacts of numerical (artificial) dispersion, which increases with scale, are not trivial. In this paper, a particle-tracking method is devised and integrated in a scale-up workflow to estimate the conditional probability distributions of multi-phase flow functions, which can be considered as inputs in coarse-scale simulations with existing commercial packages. First, a novel particle-tracking method is developed to solve the saturation transport equation. The transport calculation is coupled with a velocity update, following the implicit pressure, explicit saturation framework, to solve the governing equations of two-phase immiscible flow. Each phase particle is advanced in a deterministic convection step according to the phase velocity, as well as in a stochastic dispersion step based on the random Brownian motion. A kernel-based formulation is proposed for computation of fluid saturation in accordance with the phase particle distribution. A novel aspect is that this method employs the kernel approach to construct saturation from phase particle distribution, which is an important improvement to the conventional box method that necessitates a large number of particles per grid cell for consistent saturation interpolation. The model is validated against various analytical solutions. Finally, the validated model is integrated in a statistical scale-up procedure to calibrate effective, or “pseudo,” multi-phase flow functions (e.g., relative permeability functions). The proposed scale-up framework does not impose any length scale requirement regarding the distribution of sub-grid heterogeneities.

Simultaneous removal of arsenic and antimony from mining wastewater using granular TiO2: Batch and field column studies

Coexisting arsenic (As) and antimony (Sb) in mining wastewater is a common and great concern. On-site simultaneous removal of As and Sb from mining wastewater was achieved by using a reusable granular TiO2 column in this study. To evaluate the accuracy of the scale-up procedure, As and Sb adsorption from wastewater was studied in both large (600g TiO2) and small columns (12g TiO2) based on the proportional diffusivity rapid small-scale column tests (PD-RSSCTs) design. The comparable As and Sb breakthrough curves obtained from small and large columns confirmed the accuracy of the PD-RSSCT theory in the design of large-scale columns. Meanwhile, the consistent As and Sb adsorption results from batch and column experiments suggested that TiO2 adsorption for As and Sb can be predicted from bench-scale tests. Charge distribution multi-site complexation (CD-MUSIC) and one-dimensional transport modeling integrated in the PHREEQC program were performed to study the adsorption behaviors of As and Sb on the TiO2 surface. Coexisting ions, such as Ca2+, Mg2+, and Si4+, play an important role in As and Sb adsorption, and the breakthrough curves were well simulated after considering the compound ion effects. The results from this study highlight the surface reactions of As and Sb on TiO2 and provide a practical way for on-site remediation of industrial wastewater.

Statistical scale-up of 3D particle-tracking simulation for non-Fickian dispersive solute transport modeling

Numerical techniques for subsurface flow and transport modeling are often limited by computational limitations including fine mesh and small time steps to control artificial dispersion. Particle-tracking simulation offers a robust alternative for modeling solute transport in subsurface formations. However, the modeling scale usually differs substantially from the rock measurement scale, and the scale-up of measurements have to be made accounting for the pattern of spatial heterogeneity exhibited at different scales. Therefore, it is important to construct accurate coarse-scale simulations that are capable of capturing the uncertainties in reservoir and transport attributes due to scale-up. A statistical scale-up procedure developed in our previous work is extended by considering the effects of unresolved (residual) heterogeneity below the resolution of the finest modeling scale in 3D. First, a scale-up procedure based on the concept of volume variance is employed to construct realizations of permeability and porosity at the (coarse) transport modeling scale, at which flow or transport simulation is performed. Next, to compute various effective transport parameters, a series of realizations exhibiting detailed heterogeneities at the fine scale, whose domain size is the same as the transport modeling scale, are generated. These realizations are subjected to a hybrid particle-tracking simulation. Probabilistic transition time is considered, borrowing the idea from the continuous time random walk (CTRW) technique to account for any sub-scale heterogeneity at the fine scale level. The approach is validated against analytical solutions and general CTRW formulation. Finally, coarse-scale transport variables (i.e., dispersivities and parameterization of transition time distribution) are calibrated by minimizing the mismatch in effluent history with the equivalent averaged models. Construction of conditional probability distributions of effective parameters is facilitated by integrating the results over the entire suite of realizations. The proposed method is flexible, as it does not invoke any explicit assumption regarding the multivariate distribution of the heterogeneity. In contrast to other hierarchical CTRW formulation for modeling multi-scale heterogeneities, the proposed approach does not impose any length scale requirement regarding sub-grid heterogeneities. In fact, it aims to capture the uncertainty in effective reservoir and transport properties due to the presence of heterogeneity at the intermediate scale, which is larger than the finest resolution of heterogeneity but smaller than the representative elementary volume, but it is often comparable to the transport modeling scale.

A multi-scale particle-tracking framework for dispersive solute transport modeling

Particle-tracking simulation offers a fast and robust alternative to conventional numerical discretization techniques for modeling solute transport in subsurface formations. A common challenge is that the modeling scale is typically much larger than the volume scale over which measurements of rock properties are made, and the scale-up of measurements have to be made accounting for the pattern of spatial heterogeneity exhibited at different scales. In this paper, a statistical scale-up procedure developed in our previous work is adopted to estimate coarse-scale (effective) transition time functions for transport modeling, while two significant improvements are proposed: considering the effects of non-stationarity (trend), as well as unresolved (residual) heterogeneity below the fine-scale model. Rock property is modeled as a multivariate random function, which is decomposed into the sum of a trend (which is defined at the same resolution of the transport modeling scale) and a residual (representing all heterogeneities below the transport modeling scale). To construct realizations of a given rock property at the transport modeling scale, multiple realizations of the residual components are sampled. Next, a flow-based technique is adopted to compute the effective transport parameters: firstly, it is assumed that additional unresolved heterogeneities occurring below the fine scale can be described by a probabilistic transit time distribution; secondly, multiple realizations of the rock property, with the same physical size as the transport modeling scale, are generated; thirdly, each realization is subjected to particle-tracking simulation; finally, probability distributions of effective transition time function are estimated by matching the corresponding effluent history for each realization with an equivalent medium consisting of averaged homogeneous rock properties and aggregating results from all realizations. The proposed method is flexible that it does not invoke any explicit assumption regarding the multivariate distribution of the heterogeneity.

Design, process simulation and construction of a 100 kW pilot-scale CO2 membrane rig: Improving in situ CO2 capture using selective exhaust gas recirculation (S-EGR)

Carbon capture and storage (CCS) from natural gas-fired systems is an emerging field and many of the concepts and underlying scientific principles are still being developed. Preliminary studies suggest this approach can boost the CO2 content in the feed gas up to 3 times compared to the ‘no recycle’ case (CO2 concentration increased to 18% vs. 6%), with a consequent reduction in flow to the post-combustion capture unit by a factor of three compared to conventional, non-S-EGR. For this project, Cranfield University developed a pilot-scale 100 kW CO2 membrane rig facility in order to investigate simultaneously EGR and S-EGR technologies, the latter being achieved by using a CO2 sweep air polymeric membrane. A bench-scale membrane rig has also been developed to investigate the permeability and selectivity of different polymeric membranes to CO2. Currently a small-scale polydimethylsiloxane (PDMS) membrane module is also being investigated to study its selectivity/permeability. The tests include exploring the performance improvement of the PDMS membrane using different operating conditions with a view to developing scale-up procedures for the membrane unit for the actual 100 kW pilot-scale rig.Process simulations were performed using Aspen Plus software to predict the behaviour of the pilot-scale rig using a model developed based on empirical parameters (i.e., mass transfer coefficient of CO2 through the membrane and permeance), measured in the bench-scale membrane test unit. The results show that CO2 concentrations of up to 14.9% (comparable to CO2 level in coal combustion) can be achieved with 60% EGR, with a 90% CO2 removal efficiency of the membrane units. However, the results generated with the membrane model in which specific permeance values to PDMS were applied, predicted concentrations of CO2 in flue gases up to 9.8% (v/v) for a selective recycle of 60%. The study shows that the S-EGR technique is an effective method that can provide similar conditions to that of a coal-fired power plant for the post-combustion capture system operating on natural gas-fired units, but also highlights the fact that more research is required to find more suitable materials for membranes that optimise the CO2 removal efficiencies from the flue gas.

A synthetic biological secondary metabolite, Lycogen™, produced and extracted from Rhodobacter sphaeroides WL-APD911 in an optimizatioal scale-up strategy

The optimization of fermentation medium is important for synthetic biological secondary metabolite productions. The effect of rotation speed, inoculum amount, and medium supplements on the cell growth and Lycogen™ secretion of photobacterium Rhodobacter sphaeroides WL-APD911 was evaluated. The results reveal that a higher rotational speed exhibit a higher cell density, and the increasing in the amount of inoculum amount show a slight augment on the growth of R. sphaeroides WL-APD911.In the case of nitrogen sources adding, Lycogen™ production was achieved with a 0.5mM l-lysine supplementation. Moreover, the attention of Tween 80 presented a tremendous increase in the secondary metabolite. Response surface methodology (RSM) exhibited the optimization of medium supplements for Lycogen™ invention is accomplished at molasses concentration of 10g/L, yeast extract concentration of 40g/L, 0.3% Tween 80 and NaCl concentration of 5g/L, respectively. Further, the batch fermentation is carried out in both 5L and 20L fermentors to study the scale-up process factors to be adopted. At a 20L fermentor, Lycogen™ yields under the optimal culture condition are over 2 times than in the shake flask. The present results provide the Lycogen™ optimal culture mediums, scale-up procedures and efficient extractions from R. sphaeroides WL-APD911.

Predicting the environmental impact of a future nanocellulose production at industrial scale: Application of the life cycle assessment scale-up framework

Life cycle assessment (LCA) studies of lab-scale processes come with certain limitations as they are not reflecting e.g. higher efficiencies of large-scale production. To address this, we developed in an earlier manuscript a scale-up framework for chemical processes which is applied in this paper here. Following the framework's five-step procedure on the case of a new nanocellulose production pathway, a scaled-up LCA study for a future production of nanocellulose is performed. The comparison of these LCA results with competing and already commercially produced materials as well as with the lab-scale process demonstrates the usefulness of the whole scale-up procedure. The example shows that the environmental impact per kg of produced nanocellulose yarn can be lowered by a factor of up to 6.5 compared to the laboratory production, reflecting a projected impact that is closer to the values of an actual production plant in case the material will be commercialized. Our results got also better comparable to those of competing materials, showing values that are up to three times smaller than for carbon fibers. Looking into the process, the chosen example of nanocellulose shows a considerable change concerning the relative contributions of the various process steps. While in the lab scale, the enzymatic treatment step – which involved heating for an extended period – was the dominant contributor, this step proved to be negligible in terms of environmental impact at industrial-scale production given that a more efficient and well-insulated reactor is used. The identification of such changes is a major added value of the applied scale-up framework which cannot be achieved with scale-up procedures using a simple, global scaling factor. One of the main purposes of the whole scale-up at such an early stage is to give improvement recommendations. The framework can be considered as being an effective support for eco-design purposes, helping in identifying hotspots for process improvements. It gives a better understanding of the process and shows the practical scalability of the various steps. Overall, it can assist in steering the research of new chemicals and materials more towards an industrial application.

Total water production capacity inversion phenomenon in multi-stage direct contact membrane distillation: A theoretical study

The low thermal efficiency and low water production are among the major challenges that prevent membrane distillation (MD) process from being commercialized. In an effort to design an efficient multi-stage direct contact MD (DCMD) unit through mathematical simulation, a new phenomenon that we refer to as total water production capacity inversion (WPI) has been detected. It is represented by a decrease in the total water production beyond a number of stages or a certain module length. WPI phenomenon, which was confirmed by using two different mathematical models validated experimentally, was found to take place due to the decrease in water vapor flux across the membrane as well as the increase in heat loss by conduction as the membrane length increases. Therefore, WPI should be considered as a critical MD design-criterion, especially for large scale units. Investigations conducted for a simulated multi-stage DCMD process showed that inlet feed and permeate temperatures difference, feed and permeate flow rates, and feed salinity have different effects on WPI. The number of stages (or module length at constant width) that leads to a maximum water production has been determined for different operating parameters. Decreasing inlet feed and permeate temperatures difference, or inlet feed and permeate flow rates and increasing inlet feed temperature at constant temperature difference or inlet feed salinity cause the WPI to take place at lower number of stages. Even though the feed salinity affects negligibly the mean permeate flux, it was clearly shown that it can affect WPI. The results presented herein unveil a hidden phenomenon that is likely to occur during process scale-up procedures and should be considered by process engineers for a proper choice of system design and operating conditions.