SEARCH · Engineering Papers
Results for “Distillation”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Improved production of 76Br, 77Br and 80mBr via CoSe cyclotron targets and vertical dry distillation
Not provided.
Comparative techno-economic analysis and process design for indirect liquefaction pathways to distillate-range fuels via biomass-derived oxygenated intermediates upgrading: Liquid Transportation Fuel Production via Biomass-derived Oxygenated Intermediates Upgrading
This paper presents a comparative techno-economic analysis (TEA) of five conversion pathways from biomass to gasoline-, jet-, and diesel-range hydrocarbons via indirect liquefaction with specific focus on pathways utilizing oxygenated intermediates. The four emerging pathways of interest are compared with one conventional pathway (Fischer-Tropsch) for the production of the hydrocarbon blendstocks. The processing steps of the four emerging pathways include: biomass to syngas via indirect gasification, gas cleanup, conversion of syngas to alcohols/oxygenates followed by conversion of alcohols/oxygenates to hydrocarbon blendstocks via dehydration, oligomerization, and hydrogenation. Conversion of biomass-derived syngas to oxygenated intermediates occurs via three different pathways, producing: 1) mixed alcohols over a MoS2 catalyst, 2) mixed oxygenates (a mixture of C2+ oxygenated compounds, predominantly ethanol, acetic acid, acetaldehyde, ethyl acetate) using an Rh-based catalyst, and 3) ethanol from syngas fermentation. This is followed by the conversion of oxygenates/alcohols to fuel-range olefins in two approaches: 1) mixed alcohols/ethanol to 1-butanol rich mixture via Guerbet reaction, followed by alcohol dehydration, oligomerization, and hydrogenation, and 2) mixed oxygenates/ethanol to isobutene rich mixture and followed by oligomerization and hydrogenation. The design features a processing capacity of 2,000 tonnes/day (2,205 short tons) of dry biomass. The minimum fuel selling prices (MFSPs) for the four developing pathways range from $3.40 to $5.04 per gasoline-gallon equivalent (GGE), in 2011 US dollars. Sensitivity studies show that MFSPs can be improved with co-product credits and are comparable to the commercial Fischer-Tropsch benchmark ($3.58/GGE). Overall, this comparative TEA study documents potential economics for the developmental biofuel pathways via mixed oxygenates.
Optimization of distillation configurations for multicomponent-product distillations
Not provided.
Importance of feed recirculation for the overall energy consumption in membrane distillation systems
Not Available
Shale gas produced water management using membrane distillation: An optimization-based approach
Not provided.
Systematic Process Intensification involving Zeotropic Distillation
Distillation is commonly used for separating homogeneous fluid mixtures. While it is based on a simple thermally driven vapor-liquid equilibrium phenomenon at the two-phase region, different variants of distillation systems exist. These include simple distillation, dividing wall columns, pressure swing distillation, thermally coupled distillation and reactive distillation. Complex separation may also involve multiple distillation in a sequence to achieve the desired products. These sequences can be constructed as direct sequence, indirect sequence or thermally coupled columns. Even when a sequence is fixed, each column in the sequence can have a plethora of design alternatives to consider. All these make the design and intensification of distillation systems a challenging task. The large number of plausible design alternatives increases the combinatorial complexity for screening. Although significant efforts have been made in the past, we still lack a method for systematic identification of novel pathways for process intensification of distillation system. This is due to the lack of a generalized representation of all plausible alternatives in a single modeling and optimization framework. In this work, we first present a general representation of thermally driven vapor-equilibrium phenomenon using abstract building blocks. Specifically, each tray in a distillation column is represented by a liquid block and a vapor block with a shared semi-restricted boundary representing the interface. The arrangement of these building blocks in a two-dimensional grid gives rise to all plausible variants of distillation systems. These systems range from simple distillation, dividing wall columns to task-integrated columns. This enables us to systematically identify both classic and out-of-the-box intensified designs at the column and flowsheet levels. The overall distillation-based separation process synthesis problem is formulated as a single mixed-integer nonlinear programming (MINLP) model. In conclusion, the proposed approach is applied to multi-component zeotropic systems to show the capability of identifying promising intensified alternatives.
Production and distillative recovery of valuable lignin-derived products from biocrude
Value-added chemicals present in liquid products from direct liquefaction of biomass can be recovered as bioproducts in an integrated biorefinery to enhance the economic viability of biomass-to-liquid fuel technologies and afford a higher return on investment. In recent efforts, RTI International is exploring and developing processes that could be used to produce bioproducts in addition to liquid fuel from biocrude intermediates. The present study focused on the production and recovery of high-value lignin-derived compounds from biocrude. Catalytic pyrolysis with a nonzeolite, alumina-based catalyst was used to produce the biocrude from loblolly pine in RTI's 1-tonne per day pilot-scale plant. Distillation was evaluated as a potential separation method given that the biocrude is relatively thermally stable and distillable compared to raw pyrolysis oils. The distillation studies were performed with a laboratory distillation unit (PETRODIST 300 CC) and the biocrude was fractionated into four distillate cuts: cut 1 (IBP-110 °C), cut 2 (110–200 °C), cut 3 (200–300 °C), and cut 4 (300–400 °C). In a case study, cut 3 was distilled further to concentrate the lignin-derived chemicals boiling between 200 and 270 °C. The results showed that a biocrude containing about 10 wt% guaiacols could be concentrated to about 35 wt% of guaiacols (representing 75% recovery) in the first distillation step. The second distillation step increased the concentration of guaiacols to about 53 wt% (representing 80% recovery). Furthermore, these findings suggest that it is possible to isolate and concentrate the lignin-derived products using a distillation column with a number of plates/trays. The yields, physicochemical properties, and chemical composition of the fractions, as well as the overall distillation separation efficiency, are reported.
Miniature Distillation Column for Producing LOX From Air
The figure shows components of a distillation column intended for use as part of a system that produces high-purity liquid oxygen (LOX) from air by distillation. (The column could be easily modified to produce high-purity liquid nitrogen.) Whereas typical industrial distillation columns for producing high-purity liquid oxygen and/or nitrogen are hundreds of feet tall, this distillation column is less than 3 ft (less than about 0.9 m) tall. This column was developed to trickle-charge a LOX-based emergency oxygen system (EOS) for a large commercial aircraft. A description of the industrial production of liquid oxygen and liquid nitrogen by distillation is prerequisite to a meaningful description of the present miniaturized distillation column. Typically, such industrial production takes place in a chemical processing plant in which large quantities of high-pressure air are expanded in a turboexpander to (1) recover a portion of the electrical power required to compress the air and (2) partially liquefy the air. The resulting two-phase flow of air is sent to the middle of a distillation column. The liquid phase is oxygen-rich, and its oxygen purity increases as it flows down the column. The vapor phase is nitrogen-rich and its nitrogen purity increases as it flows up the column. A heater or heat exchanger, commonly denoted a reboiler, is at the bottom of the column. The reboiler is so named because its role is to reboil some of the liquid oxygen collected at the bottom of the column to provide a flow of oxygen-rich vapor. As the oxygen-rich vapor flows up the column, it absorbs the nitrogen in the down-flowing liquid by mass transfer. Once the vapor leaves the lower portion of the column, it interacts with down-flowing nitrogen liquid that has been condensed in a heat exchanger, commonly denoted a condenser, at the top of the column. Liquid oxygen and liquid nitrogen products are obtained by draining some of the purified product at the bottom and top of the column, respectively. Because distillation is a mass-transfer process, the purity of the product(s) can be increased by increasing the effectiveness of the mass-transfer process (increasing the mass-transfer coefficient) and/or by increasing the available surface area for mass transfer through increased column height. The diameter of a distillation column is fixed by pressure-drop and mass-flow requirements. The approach taken in designing the present distillation column to be short yet capable of yielding a product of acceptably high purity was to pay careful attention to design details that affect mass-transfer processes.
Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control
Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.
Cogeneration using multi-effect distillation and a solar-powered supercritical carbon dioxide Brayton cycle
Supercritical carbon dioxide (sCO 2 ) Brayton cycles are considered to be a potentially viable option for reducing the cost of electricity generation from solar power tower plants, owing to theoretically high efficiency, low compressor work, and compact turbomachinery. These cycles have relatively high heat rejection temperatures (>70 degrees C), which are ideal for integration with multi-effect distillation (MED) for distillate generation from seawater, without being a parasitic load to the power plant as compared to cogeneration with steam Rankine cycle. The intermittency of solar radiation reduces the annual capacity factor of concentrating solar power (CSP) plants to about 50-60% even with a molten salt storage tank of 10-h. This reduces the annual distillate generation and increases the cost of the distillate. A novel concept to reduce distillate cost is introduced, whereby the waste heat from the sCO 2 Brayton cycle is stored. A two-tank demineralized water storage tank is selected and is shown to allow for the integration of a smaller MED system operating at an increased capacity factor. The optimal storage tank design reduces the distillate cost by 19% and increase the MED capacity factor from 46.4% to 75%. Different coastal locations with good solar resource are studied for cogeneration with the CSP-sCO 2 Brayton cycle. Techno-economic analysis shows the cost of distillate produced by MED is 16% cheaper than the distillate produced from reverse osmosis system for Yanbu, Saudi Arabia.