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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Global optimization of multicomponent distillation configurations: 2. Enumeration based global minimization algorithm

We present a general Global Minimization Algorithm (GMA) to identify basic or thermally coupled distillation configurations that require the least vapor duty under minimum reflux conditions for separating any ideal or near-ideal multicomponent mixture into a desired number of product streams. In this algorithm, global optimality is guaranteed by modeling the system using Underwood equations and reformulating the resulting constraints to bilinear inequalities. The speed of convergence to the globally optimal solution is increased by using appropriate feasibility and optimality based variable-range reduction techniques and by developing valid inequalities. As a result, the GMA can be coupled with already developed techniques that enumerate basic and thermally coupled distillation configurations, to provide for the first time, a global optimization based rank-list of distillation configurations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Global optimization of multicomponent distillation configurations: Global minimization of total cost for multicomponent mixture separations

We introduce a global optimization framework for determining the minimum cost required to distill any ideal or near-ideal multicomponent mixture into its individual constituents using a sequence of columns. This new framework extends the Global Minimization Algorithm (GMA) previously introduced by Nallasivam et al. (2016); and we refer to the new framework as the Global Minimization Algorithm for Cost (GMAC). GMAC guarantees global optimality by formulating a nonlinear program (NLP) for each and every distillation configuration in the search space and solving it using global optimization solvers. In conclusion, the case study presented in this work not only demonstrates the need for developing such an algorithm, but also shows the flexibility and effectiveness of GMAC, which enables process engineers to design and retrofit energy efficient and cost-effective distillation configurations.

42 ENGINEERING↗
DOE OSTI2015

Cryogenic distillation facility for isotopic purification of protium and deuterium

Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Dynamic process intensification of binary distillation based on output multiplicity

Process intensification focuses largely on process and equipment design . Much less emphasis has been placed on operational changes to achieve cost savings and increased efficiency. Here, this article introduces the concept of dynamic intensification, defined as changes to the dynamics, operating strategy and/or control of a process that lead to a substantially more efficient processing path. This idea is illustrated in the context of binary distillation. Output multiplicity properties are exploited to establish a new periodic operating mode based on switching between two auxiliary products, which, on a time–average basis, is more energy efficient than steady–state operation. An extensive case study is presented concerning the distillation of a propanol–acetic acid mixture, confirming the theoretical developments. In contrast to previous research (e.g., on cyclic distillation), the present concept has significant advantages as it relies on existing hardware and exploiting system nonlinearity, rather than using specialized equipment operated in a discontinuous fashion.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Dynamic process intensification: Fundamentals and implementation to ternary distillation

Distillation remains a key technology for separating liquid mixtures. Its versatility comes with the disadvantage of high energy consumption. We previously used empirical arguments to introduce dynamic process intensification (DPI) as a strategy for improving the energy efficiency of binary distillation. In this article, we focus on ternary distillation; we begin by providing a rigorous basis for DPI, then formulate the problem of identifying the operating states for DPI as a nonlinear optimization problem. Via an extensive case study considering a hydrocarbon mixture, we demonstrate that reboiler energy use can be reduced by more than 2.3% relative to an equivalent column operating at steady state. Here, we prove that this result is due to the fact that DPI aims to satisfy product flow and quality constraints on average in time, affording broader opportunities for optimizing column economics than steady-state operation, where constraints are met strictly at all times.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Properties and Applications of Distillate Fractions from Highly Stable Dispersions of Liquid Pyrolysis Products

Modern reprocessing and recycling methods for liquid pyrolysis products from hydrocarbon feedstock are analyzed. Hydrocarbon fractions produced during distillation of highly stable dispersions of liquid pyrolysis products from a broad fraction of light hydrocarbons and an ethane fraction are studied. The main physicochemical parameters and fractional and component compositions of the obtained distillates are determined. The products are analyzed for compliance with requirements for grade E-1 and E-18 liquid pyrolysis products. The obtained hydrocarbon distillates were found to meet requirements of TU 2451-179-00203335-2008 for grade E-1 liquid pyrolysis products.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

An MINLP formulation for the optimization of multicomponent distillation configurations

Designing configurations for multicomponent distillation, a ubiquitous process in chemical and petrochemical industries, is often challenging. This is because, as the number of components increases, the number of admissible distillation configurations grows rapidly and these configurations vary substantially in their energy needs. Consequently, if a method could identify a few energy-efficient choices from this large set of alternatives, it would be extremely attractive to process designers. This paper develops here such a method by solving a Mixed Integer Nonlinear Program (MINLP) that is formulated to pick, among the regular-column configurations of Shah and Agrawal (2010b), those configurations that have a low vapor-duty requirement. To compute the minimum vapor-duty requirement for each column within the configuration, we use techniques that rely on the Underwood’s method. The combined difficulty arising from the nonlinearity of Underwood equations and the combinatorial explosion of the choice-set of alternatives poses unmistakable challenges for the branch-and-bound algorithm, the current method of choice to globally solve MINLPs. To address this difficulty, we exploit the structure of Underwood equations and derive valid cuts that expedite the convergence of branch-and-bound by enabling global solvers, such as BARON, infer tighter bounds on Underwood roots. This provides a quick way to identify a few lucrative alternative configurations for separation of a given non-azeotropic mixture. We illustrate the practicality of our approach on a case-study concerning heavy-crude distillation and on various other examples from the literature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Porous condensers can double the efficiency of membrane distillation

Among membrane distillation (MD) configurations, air gap MD (AGMD) has superior energy efficiency at high salinity. However, flooding of the gap prevents optimal thin gap depths as water removal is a challenge. To address these challenges, this work provides the first analysis of efficiency enhancement via porous wicking conductive condensers in MD. To do so, we examined performance with experiments and comprehensive thermo-fluid numerical models; we find that the porous wick condenser significantly improves thermal efficiency, gain output ratio (GOR), and flux. MD experiments show that the porous copper foam improves the thermal efficiency of air gap membrane distillation up to 40 % and water flux up to 144 %. Numerical modeling shows the porous copper foam improves the GOR of membrane distillation in high salinity by 98.7 %, outperforming air gap MD, permeate gap MD, and conductive gap MD. Furthermore, the optimized thickness and permeability of porous condensers significantly help eliminate the risk of flooding in AGMD.

42 ENGINEERING↗
DOE OSTI2023

Optimization-Based Azeotropic Distillation System Synthesis Using Geometric Insights

The synthesis of azeotropic distillation systems is challenging due to the existence of compartments in the residue curve map coupled with the combinatorial aspects from numerous possible system configurations. In this work, an optimization-based approach is introduced to synthesize homogeneous azeotropic distillation systems. The approach employs a network-based representation generated via a matrix method. To design the distillation columns, the modified Underwood equations are adopted, in which pseudocomponent-based compositions are used. For cases where separatrices are significantly curved, corrections via piece-wise linear functions and collinearity properties are implemented. Two examples are presented to illustrate the proposed approach.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Magnetocaloric properties of distilled gadolinium: Effects of structural inhomogeneity and hydrogen impurity

High-purity Gd prepared by distillation is a structurally inhomogeneous system consisting of needle-shaped crystals of cross section 0.5–2.5 μm with near-c-axis orientation embedded in a matrix of nanosized (30–100 nm) grains. By measuring the magnetocaloric effect (MCE) directly, we find that the MCE values differ markedly for the plate-shaped samples cut out of a distillate along and perpendicular to the crystals. The effect of small controlled amounts of impurity (hydrogen) on the properties of distilled Gd is further studied. We observe opposite trends in the MCE response to hydrogen charging with respect to the crystal's orientation within the samples and discuss mechanisms interrelating the unique structural morphology with the impurity behavior. As an overall assessment, the Curie temperatures of α-GdH{sub x} solid solutions increase from 291 K up to 294 K when increasing hydrogen concentration x from 0 to 0.15. Hydrogenation is found to broaden the ferromagnetic-to-paramagnetic phase transition. Hydrogen-containing specimens demonstrate reversibility of MCE at these temperatures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Optimizing Multicomponent Distillation Configurations

Distillation is a ubiquitous process in the chemical and petrochemical industries to separate mixtures into their individual components and accounts for a large percentage of all separations in chemical and petrochemical plants. A large fraction of the separations are mixtures containing four or more components requiring multiple distillation columns that may not be optimized for energy efficiency. As a result, there are tens of thousands of suboptimal distillation columns in operation in the U.S. consuming approximately 2-3 Quads of energy per year. In addition, the equipment dedicated to separations contributes 40 – 70% of the capital and operating costs in a typical processing plant.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Magnesium production by molten salt electrolysis with liquid tin cathode and multiple effect distillation

Low-cost clean primary production of magnesium metal is important for its use in many applications, from light-weight structural components to energy technologies. This work describes new experiments and cost and emissions analysis for a magnesium metal production process. The process combines molten salt electrolysis of MgO using MgF₂-CaF₂ electrolyte and a reactive liquid tin cathode, with gravity-driven multiple effect thermal system (G-METS) distillation to separate out the magnesium product, and re-use of the tin. Electrolysis experiments with carbon anodes showed current yield above 90%, while a yttria-stabilized zirconia solid oxide membrane (SOM) anode experiment showed 84% current yield. G-METS distillation is an important component of the envisioned process. It can potentially lower costs and energy use considerably compared with conventional magnesium distillation. Techno-economic analysis including detailed mass and energy balances shows that this electrolyte composition could lower costs by utilizing CaO, which is the primary impurity in MgO, as the Hall-Héroult process uses the sodium impurity in alumina. Analysis options include: raw material types (magnesite rock vs. brine or seawater), drying and calcining using electricity vs. natural gas, and carbon vs. SOM anode type. Using SOM inert anodes results in a cost premium around 10%–15%, mostly due to higher electrical energy usage resulting from membrane resistance, and reduces GHG emissions by approximately 1 kg CO₂/kg Mg product. Capital and operating cost estimates, and cradle to gate greenhouse gas (GHG) emissions analysis under several raw material and process technology scenarios, show comparable costs and emissions to those of aluminum production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

LES simulations of a vacuum membrane distillation channel with geometric alterations

3D LES simulations were carried out to study the performance of a vacuum membrane distillation module. A wiggly wall profile with/without embedded stiffeners was considered to alleviate axial and radial temperature polarization, the cause of performance decrease in membrane distillation. Results of the flow field show the wiggles create unsteady vortex shedding inducing intense mixing in the channel. Vortex shedding intensity increases as the Reynolds number increases or stiffeners are added. 3D results show a 56% improvement in flux when moving from a flat sheet membrane to a wiggly membrane with stiffeners at a constant Reynolds number, corresponding to an improvement from 11.7 to 41.7 in the Nusselt number, showing that the alterations improved the flux performance by enhancing the heat transfer along the membrane surface and therefore alleviating temperature polarization, a critical bottleneck in membrane distillation systems. Further, a merit criterion was defined based on the Nusselt number and friction factor, and a 40% increase in merit was shown switching from a flat to a wiggly channel, while a 97% merit increase was seen going from flat to wiggly with stiffeners. A 42% enhancement in the flux was also seen moving from a straight channel to a wiggly channel at a higher Reynolds number which highlights the importance of strategically choosing the mass flow rate, as well as inducing flow separation and vortex shedding in the channel to promote mixing and dissipate the thermal boundary layer. The variation in results between the wiggly module with stiffeners and the wiggly module at high Reynolds numbers suggests enhancing mixing structures can be more impactful on flux for this geometry than increasing the flow rate to a turbulent/transitional regime. However, both are preferable for peak system flux performance. Furthermore, a 2D approximation was used to perform simulations on more extended channels to examine the length degradation. The modules with wiggly channels performed at the same flux level with a doubling of the length. On the other hand, the flat sheet modules experienced length degradation by temperature polarization and dropped in flux yield by around 13% of the short-channel value. This work illustrates that modeling the system and understanding how the performance decreases as the membrane surface area increases are critical for a larger module (scaling up from a lab to a prototype module) to maintain high flux performance.

42 ENGINEERING↗
DOE OSTI2021

Towards high-precision parton distributions from lattice QCD via distillation

We apply the Distillation spatial smearing program to the extraction of the unpolarized isovector valence PDF of the nucleon. The improved volume sampling and control of excited-states afforded by distillation leads to a dramatically improved determination of the requisite Ioffe-time Pseudo-distribution (pITD). The impact of higher-twist effects is subsequently explored by extending the Wilson line length present in our non-local operators to one half the spatial extent of the lattice ensemble considered. The valence PDF is extracted by analyzing both the matched Ioffe-time Distribution (ITD), as well as a direct matching of the pITD to the PDF. Through development of a novel prescription to obtain the PDF from the pITD, we establish a concerning deviation of the pITD from the expected DGLAP evolution of the pseudo-PDF. The presence of DGLAP evolution is observed once more following introduction of a discretization term into the PDF extractions. Observance and correction of this discrepancy further highlights the utility of distillation in such structure studies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Continuous electrocoagulation-membrane distillation unit for treating hydraulic fracturing produced water

Hydraulic fracturing oil and gas produced water is frequently highly impaired. While it is often deep well injected, there is great interest in treating this water for beneficial uses. Given the complexity of these produced waters, multiple unit operations are necessary. Electrocoagulation has been considered as a promising pretreatment technology. Here electrocoagulation is considered as a pretreatment prior to membrane distillation. The focus of this work is on understanding the electrocoagulation process in order to design an integrated unit operation. Electrocoagulation is used to remove organic compounds that will foul the membrane leading to membrane failure during membrane distillation. Using aluminum or iron electrodes, half-cell reactions in the electrocoagulation cell and electrode potentials have been calculated. Electrocoagulation was conducted using a continuous electrocoagulation reactor with actual produced water using aluminum, iron or mixed aluminum and iron electrodes. Here, the results obtained here indicate that electrocoagulation can obtain good removal efficiency of total organic carbon (TOC) by using different reaction conditions. Removal of organic compounds is essential to minimize fouling during membrane distillation. Further the performance of the electrocoagulation process depends strongly on the quality of the feed water. Insoluble species were more effectively coagulated than dissolved organic species. Continuous electrocoagulation shows great potential as a scalable unit operation for pretreating hydraulic fracturing produced water.

42 ENGINEERING↗
DOE OSTI2023

Data-driven distillation and precision prognosis in traumatic brain injury with interpretable machine learning

Traumatic brain injury (TBI) affects how the brain functions in the short and long term. Resulting patient outcomes across physical, cognitive, and psychological domains are complex and often difficult to predict. Major challenges to developing personalized treatment for TBI include distilling large quantities of complex data and increasing the precision with which patient outcome prediction (prognoses) can be rendered. We developed and applied interpretable machine learning methods to TBI patient data. We show that complex data describing TBI patients' intake characteristics and outcome phenotypes can be distilled to smaller sets of clinically interpretable latent factors. We demonstrate that 19 clusters of TBI outcomes can be predicted from intake data, a ~ 6× improvement in precision over clinical standards. Finally, we show that 36% of the outcome variance across patients can be predicted. These results demonstrate the importance of interpretable machine learning applied to deeply characterized patients for data-driven distillation and precision prognosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

A System Level Analysis of Ethanol Upgrading to Middle Distillates

We systematically study the upgrading of ethanol toward middle distillates with desired properties. To survey the large design space, we introduce a novel superstructure-based optimization framework integrating process design and fuel formulation. We show that biorefineries that produce middle distillates by upgrading lignocellulosic ethanol can have an energy return on investment (EROI) greater than 1. Additionally, we show that technological improvements can lead to significant increases in EROI. Furthermore, trade-offs between fuel properties and biorefinery profitability are established, showing how process economics are strongly influenced by fuel properties. In the case of diesel, the feasibility of producing high cetane number biofuels is demonstrated, coupled with a discussion of the technological requirements and costs to produce these superior fuels. It is also shown that the minimum fuel selling price (MFSP) can be reduced by increasing the biorefinery complexity. Lastly, we discuss the possibility of satisfying current and projected middle distillates demand in the U.S. using biofuels produced by ethanol upgrading, and we estimate the potential CO2 mitigation of these technologies.

09 BIOMASS FUELS↗
DOE OSTI2014

Resource cost results for one-way entanglement distillation and state merging of compound and arbitrarily varying quantum sources

We consider one-way quantum state merging and entanglement distillation under compound and arbitrarily varying source models. Regarding quantum compound sources, where the source is memoryless, but the source state an unknown member of a certain set of density matrices, we continue investigations begun in the work of Bjelaković et al. [“Universal quantum state merging,” J. Math. Phys. 54, 032204 (2013)] and determine the classical as well as entanglement cost of state merging. We further investigate quantum state merging and entanglement distillation protocols for arbitrarily varying quantum sources (AVQS). In the AVQS model, the source state is assumed to vary in an arbitrary manner for each source output due to environmental fluctuations or adversarial manipulation. We determine the one-way entanglement distillation capacity for AVQS, where we invoke the famous robustification and elimination techniques introduced by Ahlswede. Regarding quantum state merging for AVQS we show by example that the robustification and elimination based approach generally leads to suboptimal entanglement as well as classical communication rates.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗