Technical Paper Session I-B - The Prospect of producing Breathing Oxygen, Pure Hydrogen and propellants from the Martian Atmosphere

The cost of manned Mars missions could be significantly reduced if O2, water, and propellant were to be extracted from the CO2-rich Martian atmosphere. The objectives of this paper are to explore techniques of producing pure O2 from the Martian atmosphere, and examine chemically stable reactors for H2 production. A method for obtaining O2 on Mars is a high temperature solid oxide electrolysis of yttriastabilized zirconia (YSZ) where CO2 is electrochemically reduced to CO and pure O2 is evolved from the opposite electrode compartment. An electrochemical cell will be demonstrated for CO2 electrolysis with concomitant production of pure O2 under partial pressures commensurate with the Martian atmosphere. Also, this paper investigates the impact of the In-Situ Resource Utilization for Mars mission by providing ultra pure H2 and a chemically stable reactor in CO2- rich mixtures needed to achieve long range mobility on Mars. The fabricated rector is permeable to H2 with infinite selectivity, chemically stable in CO2, and does not require external electrical circuit. In addition, a system-level modeling will be presented to estimate cost, size, energy, power, weight, and volume equipment of a full-scale Mars mission

Characterization Of Spin-Coated Terbium-Doped Strontium Cerate Thin Film Membranes

In this article we present the synthesis and characterization of thin film membranes based on a ceramic oxide system with a perovskite structure, which is of interest in the development of solid oxide fuel cells (SOFCs) and hydrogen (H 2) separation membranes. Continuous and homogenous dense thin film membranes of terbium-doped strontium cerate (SrCe 0.95Tb 0.05O 3-δ) have been prepared from ethylene glycol-based polymeric precursors using spin-coating technique. The Polymeric precursors have been deposited on silicone-based substrates and converted to dense polycrystalline metal oxide films after a sequence of annealing treatment at relatively low temperatures (400°C). Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) techniques are used to characterize the polymeric precursor chemistry and to confirm the perovskite structure of the calcined thin films respectively. The effect of sintering temperature and number of spin-coating cycles on the surface morphology and film thickness of the calcined thin films have been studied systematically using scanning electron microscopy (SEM) and focused ion-beam (FIB) milling techniques respectively. The surface chemistry of the thin membranes has been revealed using the x-ray photoelectron spectroscopy (XPS) analysis. FIB cross-section images indicate that thin membrane films having varying thicknesses within the range of 200 nm-2 μm can be effectively produced by controlling the number of spincoating cycle combined with the proper drying and annealing cycles after each individual coating-step

Hydrogen Flux In Terbium Doped Strontium Cerate Membrane

Hydrogen production membranes of SeCe0.95Tb0.05O 3-δ are synthesized using the liquid-phase method. The membranes are of perovskite-type structure with mixed ionic-electronic conductivities. The membranes are dense providing 100% hydrogen selectivity. Hydrogen permeability is studied as a function of temperature, hydrogen partial pressure, hydrogen dry conditions, and water vapor pressure. Also, the influence of nickel deposition on hydrogen flux is evaluated

Aspen Plus™ Process Design For The Liquid Hydrogen Production By Steam Reforming Of Used Automotive Lubricating Oil

The objective of this study is to develop a process for the production of pure liquid hydrogen from used automotive lubricating oil using Aspen Plus™ Chemical Process Simulator (CPS). The reformer is simulated as a Gibbs reactor to fractionate the large oil molecules. A methane reformer converts methane into carbon monoxide and hydrogen. A water-gas shift unit, simulated as an equilibrium reactor, is used to enhance the production of hydrogen. A flash separator is used to knock out excess water from the product stream. Aspen Adsim™ is incorporated to simulate the adsorption process of the pressure swing adsorption (PSA). The off-gas is burned with air in a combustor, and the generated energy is used to heat the processing units. A hydrogen liquefaction unit, simulated as a Claude densifier cycle, is used to convert gaseous hydrogen to liquid hydrogen. The performance of plant is investigated as a function of temperature and steam-to-oil ratio

Effect Of Temperature And Spin-Coating Cycles On Microstructure Evolution For Tb-Substituted Srceo3 Thin Membrane Films

Ceramic oxides with perovskite structures (A2+B 4+O3) have been receiving considerable attention in the solid-state electrochemical systems, such as the development of solid oxide fuel cells (SOFCs), gas sensors, and hydrogen (H2) permeable membranes. The goal of this investigation is to process a terbium-doped strontium cerate (SrCe0.95Tb0.053-δ(SCT) thin membrane films by spin-coating using ethylene glycol-based polymeric precursor. Continuous and dense SrCe0.95Tb0.05O3-δ membrane thin films with neither pin-holes nor cracks are reported. The thicknesses of the membrane films are within the range of ∼ 200 nm - 2 μm. For a single spin-coating cycle, the membrane film (200 nm thick) appears to be discontinues. However, the membrane films are dens for multiple spin-coating cycles. The polymeric precursor and the microstructure of the SrCe0.95Tb 0.05O3-δ membranes are characterized using scanning electron microscopy (SEM), focused ion-beam (FIB) microscopy, and x-ray diffraction (XRD). This work reveals that good film quality with uniform texture and homogeneous structure can be produced via spin-coating technique as a function of spin-coating cycles and processing temperature. Also, surface morphology and grain size strongly depend on sintering temperature with even grain size distribution for each sintering temperature. The flexibility of the present process approach demonstrates the capability of precisely controlling the thickness of the ceramic membrane films within a sub-micron range

Microstructural Analysis Of Doped-Strontium Cerate Thin Film Membranes Fabricated Via Polymer Precursor Technique

Nanocrystalline thin film membranes of terbium (Tb)-doped strontium cerate (SrCeO3), which is of interest in the hydrogen (H2) separation and solid oxide fuel cells (SOFCs), was synthesized via polymer precursor technique. Continuous and dense thin film membranes of composition SrCe0.95Tb0.05O3 - δ were prepared using spin-coating technique by utilizing ethylene glycol (EG)-based polymeric precursor. The polymeric precursor was deposited on silicon-based substrates, and converted to dense polycrystalline thin film ceramic membranes by sintering at relatively low temperatures. The number of spin-coating cycles and sintering temperatures were systematically varied to study their effect on the film morphology, thickness, and crystallite size within the membranes. Fourier transform infrared (FTIR) spectroscopy was utilized to study the changes in the polymer chemistry during the membrane processing. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to examine thermal decomposition and thermodynamics of the synthesized precursor, respectively. The scanning electron microscopy (SEM) analysis was used to study the surface morphology and estimate average particle size as a function of number of spin-coating cycles and sintering temperatures. Atomic force microscope (AFM) was utilized to determine the roughness and quality of the spin-coated films. The membrane thickness, crystal structure, and nanocrystallite size were determined using focused ion-beam (FIB) milling and X-ray diffraction (XRD) techniques. Furthermore, the surface chemistry of the thin film membranes was studied by means of X-ray photoelectron spectroscopy (XPS). This study demonstrated that by using the EG-based polymeric precursor, dense and continuous Tb-doped SrCeO3 thin film membranes, having thicknesses in the range of 0.2-2 μm and average nanocrystallite size of 8-70 nm, can be effectively synthesized by controlling the number of spin-coating cycles and sintering temperature

Phase Equilibrium Behavior Of The Binary Systems Co 2 + Nonadecane And Co 2 + Soysolv And The Ternary System Co 2 + Soysolv + Quaternary Ammonium Chloride Surfactant

Liquid phase and molar volume data were measured for the binary system CO 2 + soysolv at (298.15, 313.15, 323.15, 333.15, and 343.15) K and the ternary system CO 2 + soysolv + quaternary ammonium chloride surfactant at (298.15, 313.15, and 333.15) K, where the composition of soysolv to the surfactant is 99:1 wt % and 80:20 wt % on a CO 2-free basis. Data were collected stoichiometrically with a high-pressure Pyrex glass cell, where no sampling or chromatographic equipment is required. The accuracy of the experimental apparatus was tested with phase equilibrium measurements for the system CO 2 + nonadecane at 313.15 K. A pressure-decay technique was used to calculate the mass of CO 2 loaded into the equilibrium section of the apparatus, and its accuracy was verified with a blank nitrogen experiment. The generated data show that CO 2 modified soysolv is an effective transport medium for the quaternary ammonium chloride surfactant

Aspen Plus\u3csup\u3eTm\u3c/sup\u3e Process Design For The Liquid Hydrogen Production By Steam Reforming Of Used Automotive Lubricating Oil

The objective of this study is to develop a process for the production of pure liquid hydrogen from used automotive lubricating oil using Aspen PlusTM Chemical Process Simulator (CPS). The reformer is simulated as a Gibbs reactor to fractionate the large oil molecules. A methane reformer converts methane into carbon monoxide and hydrogen. A water-gas shift unit, simulated as an equilibrium reactor, is used to enhance the production of hydrogen. A flash separator is used to knock out excess water from the product stream. Aspen AdsimTM is incorporated to simulate the adsorption process of the pressure swing adsorption (PSA). The off-gas is burned with air in a combustor, and the generated energy is used to heat the processing units. A hydrogen liquefaction unit, simulated as a Claude densifier cycle, is used to convert gaseous hydrogen to liquid hydrogen. The performance of plant is investigated as a function of temperature and steam-to-oil ratio

Aspen Plus™ Process Design For The Liquid Hydrogen Production By Steam Reforming Of Used Automotive Lubricating Oil

A study was carried out to develop a process for the production of pure liquid hydrogen from used automotive lubricating oil using Aspen Plus™ Chemical Process Simulator (CPS). The reformer was simulated as a Gibbs reactor to fractionate the large oil molecules. A methane reformer converts methane into CO and hydrogen. Varying the temperature of the reformer while keeping the used oil input constant at 1 kmole/hr did not have a significant impact on hydrogen production. Most of the hydrogen was produced within the reformer. The methane reformer, as well as the water gas shift reactor, enhanced the production of hydrogen. The plant generates its energy autothermally via burning the off-gas stream with air. This is an abstract of a paper presented at the 2006 AIChE Spring National Meeting (Orlando, FL 4/23-27/2006)