Ionic liquids (ILs) have been recently considered as potential entrainers for extractive distillation. The use of ILs may affect the vapor-liquid properties to aid the separation of azeotropic mixtures. In particular, their effectiveness has been observed for ethanol dehydration, showing promising perspectives for their industrial implementation. However, there is still a lack of information about the effect of ILs on the system controllability. The objective of this work is to explore the dynamic implications of the use of two types of ionic liquids on the ethanol dehydration process. An equimolar feed mixture of ethanol and water was considered, and different IL concentrations were tested. The results show that changing the IL concentration affect the degree of stabilization of the product stream, even when smooth dynamic responses were in many cases observed.

Noble gas separation by microporous materials is a promising alternative to energy-intensive cryogenic distillation method by reducing the separation cost; however, developing novel microporous materials with excellent noble gas separation performance is still challenging due to closing chemical and physical properties among the gases. In this study, we propose to separate the noble gases (He, Ne, Ar, Kr and Xe) utilizing a metal organic framework (MOF), named SIFSIX-3-Zn, with ultra-micron sized 1-dimenssional (1D) channels (3.84 Å). Density functional theory (DFT) calculations reveal that the 1D channels provide significant adsorption potential differences among the noble gas molecules in various sizes: the larger the molecular size, the stronger the adsorption potential. Grand canonical Monte Carlo (GCMC) simulations verify that the MOF exhibits exceptional equilibrium separation performance of noble gases. Remarkably, Xe/He and Xe/Ne adsorption selectivity can be as high as 645 and 596, respectively, at 298 K and 10 kPa. While Xe/Kr selectivity in mixed gas is around 12 with a Xe adsorption amount of about 2.27 mmol/g at 273 K and 100 kPa, making SIFSIX-3-Zn one of the promising materials for equilibrium separation of Xe/Kr mixtures.

Oleaginous microorganisms are among the most promising feedstocks for the production of lipids for biofuels and oleochemicals. Lipids are synthesized in intracellular compartments in the form of lipid droplets. Therefore, their qualitative and quantitative analysis requires an initial pretreatment step that allows their extraction. Lipid extraction techniques vary with the type of microorganism but, in general, the presence of an outer membrane or cell wall limits their recovery. This review discusses the various types of oleaginous microorganisms, their lipid accumulating capabilities, lipid extraction techniques, and the pretreatment of cellular biomass for enhanced lipid recovery. Conventional methods for lipid quantification include gravimetric and chromatographic approaches; whereas non-conventional methods are based on infrared, Raman, nuclear magnetic resonance, and fluorescence spectroscopic analysis. Recent advances in these methods, their limitations, and fields of application are discussed, with the aim of providing a guide for selecting the best method or combination of methods for lipid quantification.

As climate change becomes increasingly evident, reducing greenhouse gases including CO2 has received growing attention. Because CO2 is thermodynamically very stable, its conversion into value-added chemicals such as CO, CH4, or C2H4 is difficult, and developing efficient catalysts for CO2 conversion is important work. CO2 can be converted using the gas-phase reaction, liquid-phase reaction, photocatalytic reaction, or electrochemical reaction. The gas-phase reaction includes the dry reforming of methane using CO2 and CH4, or CO2 hydrogenation using CO2 and H2. The liquid-phase reaction includes formic acid formation from pressurized CO2 and H2 in aqueous solution. The photocatalytic reaction is commonly known as artificial photo-synthesis, and produces chemicals from CO2 and H2O under light irradiation. The electrochemical reaction can produce chemicals from CO2 and H2O using electricity. In this review, the heterogeneous catalysts used for the gas-phase reaction or electrochemical reactions are discussed, because the liquid-phase reaction and photocatalytic reaction typically suffer from low productivity and poor durability. Because the gas-phase reaction requires a high reaction temperature of > 600 °C, obtaining good durability is important. The strategies for designing catalysts with good activity and durability will be introduced. Various materials have been tested for electrochemical conversion, and it has been shown that specific metals can produce specific products, such as Au or Ag for CO, Sn or Bi for formate, Cu for C2H4. Other unconventional catalysts for electrochemical CO2 reduction are also introduced.

Abelmoschus esculentus okra as whole stalks was examined for its suitability for pulp and paper production. It’s, fiber dimensions, morphological and chemical characteristics were reported. The pulping trials with soda- Anthraquinone (AQ,) at different chemical charges. Application of 21% as NaOH with 0.1% AQ gave good results in degree of delignification, mechanical properties. Utilization of okra pulps and blender is recommended due to good pulp properties. Evaluation of general characteristics of okra stalks in terms of fiber dimensions morphological indices, chemical components, Soda-AQ cooking and to study their suitability for paper production. Okra Fiber dimension evaluation done after maceration with a mixture of 30% hydrogen peroxide and acetic acid (1:1) for core and bark parts separately and was carried out under microscope staining with aqueous safranin. The Soda-AQ cooks at different active alkali levels were calculated as NaOH on oven dry raw material. The fibers from okra stalks studied (core and bark) were in the range of hardwood fibers, with short fiber length, especially the core with more or less moderate walls, narrow lumen and fiber width. The fiber width of bark was medium –narrow with medium wall thickness. The ash content was rather high whereas the silica content was comparatively high The hot water extractives from okra stalks was (4.1%), cold water (0.4) ethanol/ cyclohexane (1.1), ethanol extractives (1.2%) and 1% NaOH (27.6%) were rather high. The cellulose (Kurschner-Hoffer) was (48.5%) The lignin content was (15.3%) which was relatively moderate. The use of 0.1% AQ enhanced the delignification in the three trials applied. The screened yield increase with increase of chemical dose applied while the rejects decrease. When 21% NaOH was applied, the screened yield was 32.2% with negligible amount of rejects, however with lower alkali charge 18% the screened yield was decreased to 28% with very low rejects 1.5%. on the other hand rejects were increased to 7% when 15% NaOH was applied with very low screened yield 19%.The pulps produced from okra soda-AQ are suitable for production of printing and writing papers and it is advisable to use them in blending due to good papermaking properties.

With the rapid rise in global population over the past decades, there has been a corresponding surge in demand for resources such as food and energy. As a consequence, the rate of waste generation and resultant pollution levels have risen drastically. Currently, most organic solid wastes are either land applied or sent to landfills, with the remaining fraction incinerated or anaerobically digested. However, with the current emphasis on the reduction of emissions, nutrient recovery, clean energy production and circular economy, it is important to revisit some of the conventional methods of treating these wastes and tap into their largely unrealized potential in terms of environmental and economic benefits. Wastewater sludge, with its high organic content and fairly constant supply, provides a great opportunity to implement some of these strategies using thermochemical conversion technologies, which are considered as one of the alternatives for upcycling such waste streams. This paper summarizes the results of prominent studies for valorizing wastewater sludge through thermochemical conversion technologies while drawing inferences and identifying relationships between different technical and operating parameters involved. This is followed by sections emphasizing the environmental and economic implications of these technologies, and their corresponding products in context of the broader fields of waste-to-energy, nutrient recycling and the progress towards a circular economy.

The recent roadmap of SPIRE initiative includes the development of “new separation, extraction and pre-treatment technologies” as one of the “key actions” for boosting sustainability, enhancing the availability and quality of existing resources. Membrane condenser is an innovative technology that was recently investigated for the recovery of water vapor for waste gaseous streams, such as flue gas, biogas, cooling tower plumes, etc. Recently, it has been also proposed as pre-treatment unit for the reduction and control of contaminants in waste gaseous streams (SOx and NOx, VOCs, H2S, NH3, siloxanes, halides, particulates, organic pollutants). This perspective article reports recent progresses in the applications of the membrane condenser in the treatment of various gaseous streams for water recovery and contaminant control. After an overview of the operating principle, the membranes used, and the main results achieved, the work also proposes the role of this technology as pre-treatment stage to other separation technologies. The potentialities of the technology are also discussed aspiring to pave the way towards the development of an innovative technology where membrane condenser can cover a key role in redesigning the whole upgrading process.

Living organisms in analogy with chemical factories use simple molecules such as sugars to produce a variety of compounds which are necessary for sustaining life and some of which are also commercially valuable. The metabolisms of simple (such as bacteria) and higher organisms (such as plants) alike can be exploited to convert low value inputs into high value outputs. Unlike conventional chemical factories, microbial production chassis are not necessarily tuned for a single product overproduction. Despite the same end goal, metabolic and industrial engineers rely on different techniques for achieving productivity goals. Metabolic engineers cannot affect reaction rates by manipulating pressure and temperature, instead they have at their disposal a range of enzymes and transcriptional and translational processes to optimize accordingly. In this review, we first highlight how various analytical approaches used in metabolic engineering and synthetic biology are related to concepts developed in systems and control engineering. Specifically, how algorithmic concepts derived in operations research can help explain the structure and organization of metabolic networks. Finally, we consider the future directions and challenges faced by the field of metabolic network modeling and the possible contributions of concepts drawn from the classical fields of chemical and control engineering. The aim of the review is to offer a current perspective of metabolic engineering and all that it entails without requiring specialized knowledge of bioinformatics or systems biology.

This contribution presents an hourly-based optimization of a biogas supply network to generate electricity, heat and organic fertilizer while considering multiple objectives and auction trading prices of electricity. The optimization model is formulated as a mixed-integer linear programming (MILP) utilizing a four-layer biogas supply chain. The model accounts for biogas plants based on two capacity levels of methane to produce on average 1 ± 0.1 MW and 5 ± 0.2 MW electricity. Three objectives are put forward: i) maximization of economic profit, ii) maximization of economic profit while considering cost/benefits from greenhouse gas (GHG) emissions (economic+GHG profit) and iii) maximization of sustainability profit. The results show that the economic profit accrued on hourly-based auction trading prices is negative (loss), hence, four additional scenarios are put forward: i) a scenario whereby carbon prices are steadily increased to the prevalent eco-costs/eco-benefits of global warming; ii) a scenario whereby all the electricity auction trading prices are multiplied by certain factors to find the profitability breakeven factor, iii) a scenario whereby shorter time periods are applied, and investment cost of biogas storage is reduced showing a relationship between cost, volume of biogas stored and the variations in electricity production and (iv) a scenario whereby the capacity of the biogas plant is varied from 1 MW and 5 MW as it affects economics of the process. The models are applied to an illustrative case study of agricultural biogas plants in Slovenia where a maximum of three biogas plants could be selected. The results hence present the effects of the simultaneous relationship of economic profit, economic+GHG profit and sustainability profit on the supply and its benefit to decision-making.

This paper gives a brief review of energy and CO2 emissions related topics resulting from the chemical and related industries. The main issues, challenges and opportunities are highlighted together with perspectives of process alternatives for more efficient energy consumption and CO2 emission management. Analysis of the data indicate that not all available energy resources are being utilized efficiently, while the energy resources causing the largest emissions of CO2 are being used in the largest amounts. Also, the chemical and related industries are among the largest consumers of energy, indicating that solutions for reduction of energy consumption and CO2 emissions in these industries need to be investigated. Information on promising alternatives for reduction of energy consumption and CO2 emissions are collected and a selection of them are evaluated. Also, two specific case studies involving energy intensive separation operations replaced by recently developed technologies that may achieve significant reductions in energy consumption, CO2 emissions and total annualized costs are presented. Through these examples issues of energy need versus CO2 neutral design, sustainable conversion, retrofit design, and process intensification for chemical and related industries are highlighted.

To increase permeability in O2/N2 separation without compromising selectivity, Cu3BTC2 (or HKUST-1) nanocrystals, which possess well-defined channels and high surface area, were used as the filler for mixed-matrix membrane fabrication. The Cu3BTC2 nanocrystals, which were synthesized at room temperature with a facile method, showed desirable physical properties and porosity comparable to those of a commercial Cu3BTC2 adsorbent (Basolite C300). High-quality mixed-matrix membranes without appreciable defects were successfully fabricated with both Matrimid and polysulfone, which are commercial membrane polymers that suffer from poor permeability. Gas permeation testing revealed that 20 wt% Cu3BTC2 nanocrystals loading dramatically improved the O2 permeability of both polymer membranes (106% for Matrimid and 379% for polysulfone), with modest increases in O2/N2 selectivity. A detailed analysis of diffusivity and solubility showed that the overall O2/N2 diffusion selectivity was improved substantially over that of a neat polymeric membrane with the incorporation of Cu3BTC2 nanocrystals. A comparative study with literature data demonstrated that Cu3BTC2 nanocrystals are far more effective than other metal-organic framework fillers tested to increase permeability in O2/N2 separation.

A two-step approach combining an aqueous two-phase system (ATPS) and an aqueous micellar two-phase system (AMTPS), both based on the thermo-responsive copolymer Pluronic L-35, is here proposed for the purification of proteins and tested on the sequential separation of three model proteins, cytochrome c, ovalbumin and azocasein. Phase diagrams were established for the ATPS, as well as co-existence curves for the AMTPS. Then, by scanning and choosing the most promising systems, the separation of the three model proteins was performed. The aqueous systems based on Pluronic L-35 and potassium phosphate buffer (pH = 6.6) proved to be the most selective platform to separate the proteins (SAzo/Cyt = 1667; SOva/Cyt = 5.33 e SAzo/Ova = 1676). The consecutive fractionation of these proteins as well as their isolation from the aqueous phases was proposed, envisaging the industrial application of this downstream strategy. The environmental impact of this downstream process was studied, considering the carbon footprint as the final output. The main contribution to the total carbon footprint comes from the ultrafiltration (~ 49%) and the acid precipitation (~ 33%) due to the energy consumption in the centrifugation. The ATPS step contributes to ~ 17% while the AMTPS only accounts for 0.30% of the total carbon footprint.

Recent advances in metabolic engineering have enabled the production of chemicals via bio-conversion using microbes. However, downstream separation accounts for 60–80% of the total production cost in many cases. Previous work on microbial production of extracellular chemicals has been mainly restricted to microbiology, biochemistry, metabolomics, or techno-economic analysis for specific product examples such as succinic acid, xanthan gum, lycopene, etc. In these studies, microbial production and separation technologies were selected apriori without considering any competing alternatives. However, technology selection in downstream separation and purification processes can have a major impact on the overall costs, product recovery, and purity. To this end, we apply a superstructure optimization based framework that enables the identification of critical technologies and their associated parameters in the synthesis and analysis of separation processes for extracellular chemicals generated from microbial conversions. We divide extracellular chemicals into three categories based on their physical properties, such as water solubility, physical state, relative density, volatility, etc. We analyze three major extracellular product categories (insoluble light, insoluble heavy and soluble) in detail and provide suggestions for additional product categories through extension of our analysis framework. The proposed analysis and results provide significant insights for technology selection and enable streamlined decision making when faced with any microbial product that is released extracellularly. The parameter variability analysis for the product as well as the associated technologies and comparison with novel alternatives is a key feature which forms the basis for designing better bioseparation strategies that have potential for commercial scalability and can compete with traditional chemical production methods.

Chromatography with step changes in modulator properties such as pH, solvent strength, or ionic strength to facilitate desorption is widely used in the purification of proteins and other chemicals. Step changes can be incorporated into non-isocratic simulated moving beds; however, applications of such systems have been limited because one must select numerous operating parameters (zone velocities and port velocities). The operating parameters must be selected correctly to achieve high purity, yield, and productivity and depend on a large number of system parameters (feed, material, and equipment parameters). To address this challenge, the Standing-Wave Design method has been developed for three-zone, open-loop, non-isocratic, and non-ideal systems with both linear and non-linear isotherms. This method directly links the operating parameters to the system parameters. The operating parameters can be solved from a set of algebraic equations. In contrast, for non-ideal systems, previous literature design methods require extensive search using rate model simulations, which involve solving partial differential equations at each grid point. Two examples were tested for the effectiveness of the SWD method using rate model simulations. In both examples, sorbent productivity was pressure limited. Higher pressure sorbents or equipment would lead to higher sorbent productivity. In the first example, a 3-zone open-loop simulated moving bed was designed and compared with an optimal batch step-wise elution system. Compared to batch step-wise elution systems, the simulations showed that the 3-zone open-loop SMB could give an order of magnitude higher productivity in systems with weakly competing impurities and two orders of magnitude higher in systems with strongly adsorbing impurities. In the second example, the simulations showed that an SMB designed using the Standing-Wave method could achieve an order of magnitude higher productivity than a system designed using the Triangle Theory.

One fault that occurs with heat exchangers is a tube rupture, an overpressure scenario in which high pressure fluid flows into the low pressure region. It is a serious safety concern that may lead to significant damage. Accurate prediction of the pressure build-up after a rupture is critical to determine the appropriate size of a relief device and avoid exceeding allowable pressure limits. This paper describes a model-based step-by-step methodology to predict dynamic pressure profiles during tube rupture for liquid-liquid, vapor-liquid, and flashing liquid-liquid systems. The transient effects of the relief valve are considered. The effects of choked flow must also be considered for accurate maximum pressure predictions. Using a dimensionless analysis, the pressure ratio and density ratio are shown to significantly impact the severity of this incident. Results show that vapor-liquid systems result in the highest pressure surges.

With the concentration of CO2 in the atmosphere increasing beyond sustainable limits, much research is currently focused on developing solutions to mitigate this problem. Possible strategies involve sequestering the emitted CO2 for long-term storage deep underground, and conversion of CO2 into value-added products. Conventional processes for each of these solutions often have high-capital costs associated and kinetic limitations in different process steps. Additionally, CO2 is thermodynamically a very stable molecule and difficult to activate. Despite such challenges, a number of methods for CO2 capture and conversion have been investigated including absorption, photocatalysis, electrochemical and thermochemical methods. Conventional technologies employed in these processes often suffer from low selectivity and conversion, and lack energy efficiency. Therefore, suitable process intensification techniques based on equipment, material and process development strategies can play a key role at enabling the deployment of these processes. In this review paper, the cutting-edge intensification technologies being applied in CO2 capture and conversion are reported and discussed, with the main focus on the chemical conversion methods.

The catalytic performance of NiMoAl catalysts derived from layered double hydroxide (LDH) precursors with molybdenum species incorporated into the interlayers was investigated for the hydrodeoxygenation (HDO) of anisole as a model compound of the lignin. The results showed that high dispersion of small Ni nanoparticles with 2–5 nm due to the pinning effect of Mo from Mo7O246− intercalated the LDHs. Due to presence of the oxygen vacancy sites on the molybdenum oxide, the NiMoAl catalysts exhibit higher conversion of anisole than the corresponding NiAl catalyst. The activity for hydrodeoxygenation was enhanced with the increased content of molybdenum species, which can be attributed to the larger amount of acid sites-promoted removal of oxygen from anisole. In addition, the NiMoAl catalysts show higher resistance to deactivation than the NiAl catalyst, and can be broadly applied to other hydrodeoxygenation reactions.

Biorefining of microalgae biomass requires processing of high-solids (> 10%) slurries. To date there is little knowledge of how processes for weakening and rupturing microalgae cells affect the rheological properties of these materials. To fill this gap in the literature, the rheological properties of concentrated slurries of marine microalgae Nannochloropsis sp. were investigated as a function of processing and solids concentration (12, 20 and 24% w/w). Freshly harvested, incubated (autolysed), and high-pressure homogenised (HPH) slurries were found to be shear thinning up to a shear rate of approximately 200 s− 1. Viscosity increases were far more prominent for partially processed versus unprocessed algal pastes at the higher concentrations. Slurry viscosity as a function of cell volume fraction could not be fitted to the Krieger-Dougherty model due to a network structure resulting from extracellular polymeric substances (EPS) and the intracellular cell components released during incubation and cell rupture. The 24% slurry, which was near the close packing limit, was much more viscous than the less concentrated slurries when comprising whole cells (i.e. harvested and incubated slurries). Cell rupture by HPH completely altered the characteristics of the slurry, increasing the viscosity of even the less concentrated slurries, and producing irreversible shear thinning behaviour. The magnitude of the increases in viscosities and the irreversible shear thinning behaviour observed in this study, have significant implications for processing and optimising the solids concentration of algal slurries.

Pervaporation (PV), a membrane process in which the feed is a liquid mixture and the permeate is removed as a vapour, offers an energy-efficient alternative to conventional separation processes such as distillation, and can be applied to mixtures that are difficult to separate, such as azeotropes. Here the principles of pervaporation and its industrial applications are outlined. Two classes of material that show promise for use in PV membranes are described: Polymers of intrinsic microporosity (PIMs) and 2D materials such as graphene. The literature regarding PV utilizing the prototypical PIM (PIM-1) and it hydrophilic hydrolysed form (cPIM-1) is reviewed. Self-standing PIM-1 membranes give competitive results compared to other membranes reported in the literature for the separation of alcohols and other volatile organic compounds from aqueous solution, and for organic/organic separations such as methanol/ethylene glycol and dimethyl carbonate/methanol mixtures. Blends of cPIM-1 with conventional polymers improve the flux for dehydration of alcohols. The incorporation of fillers, such as functionalised graphene-like fillers, into PIM-1 to form mixed matrix membranes can enhance the separation performance. Thin film composite (TFC) membranes enable very high fluxes to be achieved when a suitable support with high surface porosity is utilised. When functionalised graphene-like fillers are introduced into the selective layer of a TFC membrane, the lateral size of the flakes needs to be carefully controlled. There is a wide range of PIMs and 2D materials yet to be explored for PV applications, which offer potential to create bespoke membranes for a wide variety of organic/aqueous and organic/organic separations.

There is a demand for new chemical reaction technologies and associated engineering aspects due to on-going transition in energy and chemistry associated to moving out progressively from the use of fossil fuels. Focus is given in this review on two main aspects: i) the development of alternative carbon sources and ii) the integration of renewable energy in the chemical production. It is shown how addressing properly these aspects requires to develop also a) new tools for chemical engineering assessment and b) innovative methodologies for the development of the materials, reactors and processes. This review evidences the need to accelerate studies on these directions, being a crucial element to catalyze the transition to a more sustainable use of energy and chemistry. It is remarked, however, the need to go beyond the traditional approaches, with some examples given. In fact, the presence of radical changes in the way of production is underlined, requiring thus novel fundamentals and applied engineering approaches.