Supercritical Fluids Experimental Facility

Facility Description

The Supercritical Fluids Experimental Facility at Los Alamos engages in basic and applied research in the use of supercritical fluids (SCFs) in industrial and defense-related processes.

Some areas of particular interest are

• precision cleaning/degreasing
• analytical methods development
• extraction of contaminants and solvents
• chemical synthesis
• polymer synthesis
• chemical waste destruction
• semiconductor processing
• chemical separations
• materials modification (cements, polymers)
• alternative solvent/waste minimization

The facility is available to help users evaluate whether SCFs can solve their specific environmental, cleaning, and processing problems. Supercritical fluids are attractive solvents because of their high diffusivities, low viscosities, and adjustable solvent strengths. In the case of nontoxic and nonflammable carbon dioxide (CO₂), its critical temperature and pressure are readily accessible with well-established process technology and equipment. Carbon dioxide is easily separable after processing due to its volatility and can replace hazardous organic solvents in many chemical transformations, including

• unimolecular organic
• solute fractionation
• antisolvent processing
• coatings removal
• fluid-bed processing
• transformations
• asymmetric catalysis (hydrogenation, hydrogen transfer reduction, oxidation of olefins, Lewis-acid catalysis)
• selective oxidative functionalizations
• phase-transfer catalysis
• metal-catalyzed polymerizations
• organic synthetic reactions (Friedel-Crafts alkylations and acylations)

Related studies have included reactions in which CO2 is both a solvent and reagent, photochemical selectivity, solvent and cage effects, and fundamental acid/base chemistry.

Supercritical water can be used as an oxidation medium for the complete conversion of organic wastes to carbon dioxide and other benign products. At Los Alamos, we have demonstrated that hydrothermal conditions are capable of processing highly corrosive and salt-containing organic wastes as well, such as Hanford tank waste. Hydrothermal conditions can also be used for dissolution, crystallization, and processing of materials. Los Alamos has extensive capabilities for fluid dynamics modeling for complex reactor geometries, and process modeling and control in complex chemical environments. Multi-phase flow situations can be modeled in detail by computational fluid dynamic (CFD) calculations. Process modeling capabilities range from the scale of molecular dynamics simulations through lumped parameter descriptions of unit operations (e.g., reactors and separators) and extends to the level of process flow-sheet simulation and optimization.

Users of the Supercritical Fluids Experimental Facility may choose an exploratory evaluation in which problems are solved using existing equipment or a long-term collaboration evaluating a broad scope of problems.

Equipment

• Large- and small-scale supercritical fluid cleaning and extraction equipment
• Continuous-flow tubular reactors for the measurement of kinetics and corrosion reactions
• Batch reactors (up to 1-L volume) with sampling and temperature control (-20 to 600 degrees Celsius) for reaction studies in supercritical water, CO2, other fluids, and mixtures of supercritical fluids
• Flow and batch reactors with protective liners (such as titanium and platinum) for corrosive mixtures
• Reactors with optical access for spectroscopic and photochemical studies (IR, Raman, UV-vis), and in situ NMR spectroscopy
• Phase equilibria and physical property measurements (e.g., density, diffusion, viscosity, solubility), using custom-designed and commercial equipment
• Extensive high-pressure generation equipment and instrumentation
• Handling of explosive and radioactive materials in appropriate facilities
• In situ laser spectroscopy facilities (e.g., laser-induced grating, CARS, picosecond/femtosecond) for species identification, solvation effects, and molecular dynamics
• Extensive, state-of-the-art analytical capabilities for water analysis, organic/inorganic identification and quantification, and chiral separation
• General computational facilities for fluid dynamics (e.g., FLUENT, FIDAP, POLYFLOW), process simulation (ASPEN), detailed chemical kinetics (CHEMKIN), as well as a variety of more specialized codes developed at Los Alamos.

Facility Access

The Supercritical Fluids Experimental Facility provides OPEN access to users.

Last update: 25 June 2003