NETL is working to help produce and deliver hydrogen from fossil fuels including coal in commercially applicable, environmentally acceptable ways. To achieve this strategic national goal, advanced hydrogen separation technologies are needed to supply tomorrow's energy and transportation systems with affordable hydrogen fuel.

NETL's Hydrogen Separation Group investigates, evaluates, and develops hydrogen separation membranes and materials. Researchers are focused on developing stable and robust membranes that are suitable for the rapid, selective removal of hydrogen from mixed gas streams. These membranes also must be resistant to chemical impurities such as sulfur, an abundant component of coal and a key feedstock for producing hydrogen.

NETL's Hydrogen Separation Facilities support research in four main areas:

• Membrane Materials – investigate and develop materials and fabrication techniques for producing suitable membranes for separating hydrogen.
• Membrane Performance Testing – characterize the performance of promising novel membranes by using continuous gas feed streams and conditions similar to industrial processes.
• Water-Gas Shift Membrane Reactor Development – develop a membrane reactor for enhancing hydrogen production from the water-gas shift (WGS) reaction at high temperature and pressure with no added catalyst.
• Advanced Separation Science – explore new concepts and conduct fundamental studies to reduce hydrogen production costs, for example, by studying CO₂ -selective membranes and the chemistry of hydrogen transport and sulfur poisoning.

NETL also conducts membrane performance testing on novel prototypes in collaboration with other R&D groups including Los Alamos National Laboratory, Oak Ridge National Laboratory, Argonne National Laboratory, REB Research, and Ames Laboratory/Iowa State University. The purpose of this testing is to validate results and to develop a baseline for future research in this area.

State-of-the-art facilities and instrumentation include:

• Hydrogen Membrane Test (HMT) Units: These three units provide a unique capability to measure high-pressure, high-temperature hydrogen membrane flux at conditions of up to 1,000 psi at 900 ºC. The units can accommodate both disk and tubular membrane configurations at a wide range of flow rates for process gases. In addition, the HMT units have the flexibility to be used for both membrane separation testing and membrane reactor testing.
  • HMT-1 – dedicated to studies that utilize sulfur-laden, “dirty” gas streams without concern for cross-contamination with clean gases.
  • HMT-2 – used as a “clean” system to compare gas mixtures containing no sulfur compounds.
  • HMT-3 – optimized for testing membrane reactor systems, such as the WGS system, but also can be used for membrane separation testing.
• Membrane Screening Systems: Laboratory membrane screening systems (MSS) are used for small-scale, low-pressure analysis of membrane permeability under different environments, to establish their capacity for hydrogen separation. These systems also are used to study conditioning of materials prior to characterizing their properties. Using these systems, for example, researchers can conduct short-term tests of membrane materials with different gas mixtures containing sulfur at varying temperatures.
• Materials Lab: Membrane fabrication resources include a well-equipped laboratory for preparation of inorganic materials. Equipment includes high-temperature, controlled atmosphere furnaces (used for material synthesis as well as brazing), a precision tungsten inert gas (TIG) welder, presses, and cold plasma sputter coaters. Machine shop facilities are also available, and a capability for small-scale in-house alloy preparation has been developed.
• ASPEX PSEM: An Aspex PSEM 2000 personalized scanning electron microscope, equipped with an energy dispersive x-ray detector (EDS), is used for membrane and materials characterization. Changes in membrane morphology, element migration, layer thickness, and pore size are among the characteristics studied.
• PANalytical XRD: A PANalytical X-Ray Diffraction instrument, with a hot stage and high-speed detector, is used to determine and observe membrane material crystal structure under realistic operating conditions.

Other analytical capabilities at NETL that may be utilized for membrane and materials characterization include:

• Multitechnique Omicron Surface Analysis and Imaging System
  • STM (scanning tunneling microscopy)
  • AFM (atomic force microscopy)
  • XPS (X-ray photoelectron spectroscopy)
  • AUGER (auger electron spectroscopy)
  • ISS (ion scattering spectroscopy)
  • LEED (low energy electron diffraction)
    
• Standalone instrumentation
  • XPS with small spot capability
  • AFM
  • IRAS (infrared reflection absorption spectroscopy)
  • FTIR (Fourier transform infrared) and Raman spectroscopy (both with microscopes)
  • BET ( Branauer-Emmett-Teller ) surface area analysis
  • Chemisorption and physisorption analyzer

HMT Unit


WGS Membrane Reactor

For more information contact: Richard Killmeyer