580 California St., Suite 400
San Francisco, CA, 94104
Key research themes
1. How can viscosity and transport properties of natural and mixed gases be accurately predicted under varying pressure and temperature conditions?
This research area emphasizes experimental measurement and semiempirical modeling of viscosity and other transport properties (diffusion, thermal conductivity) for natural gases and their mixtures over wide ranges of pressure and temperature, foundational for design and safety in gas transport operations. Accurate, generalized correlations usable with limited experimental data are critical for practical engineering applications.
Key finding: Presented extensive experimental viscosity and density data for four natural gases at temperatures from 100 to 340°F and pressures up to 8,000 psia, establishing an extended semiempirical correlation incorporating predicted... Read more
Key finding: Developed an inversion technique based on Chapman-Enskog kinetic theory using Lennard-Jones potentials to predict viscosity, diffusion, thermal diffusion factor, and thermal conductivity of five equimolar CF4-noble gas... Read more
Key finding: Using ab initio potential energy functions and classical kinetic theory, the study predicted viscosity, diffusion, and thermal conductivity coefficients for dilute radium-halogen gas mixtures over a temperature range up to... Read more
2. What are the safety implications and transport challenges of natural gas mixed with ammonia or hydrogen through existing pipeline infrastructure?
This theme investigates the industrial and fire safety risks, mechanical and chemical challenges, and feasibility of transporting blends of natural gas with ammonia or hydrogen in current gas pipeline networks. It includes assessing toxic and flammable hazards from accidental leaks, blending limits from a safety perspective, mathematical modeling of compressible gas flow of mixtures under high pressure, and strategies for compression and safe operation of mixed-gas pipelines.
Key finding: Conducted a comprehensive hazard assessment of pipeline transport of natural gas and its mixtures with ammonia, identifying risk zones from uncontrolled releases that can cause fires or toxic hazards. Found that mixed NH3/CH4... Read more
Key finding: Presented a detailed analysis of compressibility and steady-state flow modeling of methane-hydrogen mixtures through existing high-pressure pipelines, highlighting that hydrogen admixtures below 10-25% vol generally pose... Read more
3. How do gas migration, diffusion, and slippage phenomena affect gas transport in porous materials and confined geometries relevant to energy extraction and environmental safety?
This field focuses on the mechanisms and modeling of gas movement through porous and granular media, including granular gases, coal seams, tight formations, concrete, and soft granular materials. It addresses diffusion processes in confined conditions, slippage effects at pore walls, phase transitions such as hydrate formation, and granular material deformation under gas injection, all critical for optimizing resource recovery and managing environmental hazards.
Key finding: Established experimentally that gas diffusion capacity in coal increases with temperature due to higher molecular kinetic energy and accelerated desorption, and that higher adsorption equilibrium pressure leads to greater... Read more
Key finding: Through experiments with N2, He, and CO2 gases in micro-Darcy permeability cores, demonstrated the presence of Knudsen diffusion regimes and gas slippage effects in nanopores (<10 nm), indicating that gas-wall collisions... Read more
Key finding: Developed a thermodynamically consistent model for producing, transporting, and regasifying natural gas hydrates as a medium for stranded gas transport. Validated heat loss reduction via insulating membrane diameter and... Read more
Key finding: Experimentally showed that increasing confinement stress in a packing of soft granular particles transitions gas migration mechanisms from fluidization to pathway opening to pore invasion, with mixed regimes producing greater... Read more
Key finding: Designed a novel diffusion measurement device and directly measured diffusion coefficients in dry industrial concrete, demonstrating that gas transport under very low-pressure conditions is dominated by molecular diffusion... Read more