Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “SO3”

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.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaH5S2O9 by Materials Project

(NaH4(SO3)2)2H2O2(O2)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two hydrogen peroxide molecules; four water molecules; four water molecules; and one NaH4(SO3)2 sheet oriented in the (1, 0, 0) direction. In the NaH4(SO3)2 sheet, Na1+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.48 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one S6+ atom. The H–S bond length is 1.40 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.04 Å) and one longer (1.56 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to one H1+ and two O2- atoms. There is one shorter (1.50 Å) and one longer (1.53 Å) S–O bond length. In the second S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of S–O bond distances ranging from 1.47–1.64 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one S6+ atom. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one H1+, and one S6+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one H1+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to one H1+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one Na1+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one H1+, and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaH5(SO4)3 by Materials Project

NaH(SO3)2H2O2H2SO2O2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of two hydrogen peroxide molecules; four water molecules; two H2SO2 clusters; and one NaH(SO3)2 ribbon oriented in the (1, 0, 0) direction. In each H2SO2 cluster, there are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one S6+ atom. The H–S bond length is 1.39 Å. S6+ is bonded in a distorted trigonal non-coplanar geometry to one H1+ and two O2- atoms. There is one shorter (1.49 Å) and one longer (1.65 Å) S–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a water-like geometry to one H1+ and one S6+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one S6+ atom. In the NaH(SO3)2 ribbon, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.94 Å. H1+ is bonded in a single-bond geometry to one S6+ atom. The H–S bond length is 1.39 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded in a distorted trigonal non-coplanar geometry to one H1+ and two O2- atoms. There is one shorter (1.47 Å) and one longer (1.97 Å) S–O bond length. In the second S6+ site, S6+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.48 Å) and one longer (1.49 Å) S–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Na1+ and one S6+ atom. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to one Na1+ and one S6+ atom. In the third O2- site, O2- is bonded in a distorted L-shaped geometry to one Na1+ and one S6+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Na1+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one S6+, and one O2- atom. The O–O bond length is 1.30 Å. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Na1+ and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaH2S5O6 by Materials Project

BaH2(SO3)2(S)3 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of twelve hydrogen sulfide molecules and two BaH2(SO3)2 sheets oriented in the (0, 0, 1) direction. In each BaH2(SO3)2 sheet, Ba2+ is bonded in a 9-coordinate geometry to three H1+ and six O2- atoms. There are a spread of Ba–H bond distances ranging from 2.98–3.02 Å. There are a spread of Ba–O bond distances ranging from 2.71–2.80 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a bent 120 degrees geometry to two equivalent Ba2+ atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ atom. S+1.60+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.47 Å) and one longer (1.48 Å) S–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and one S+1.60+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+1.60+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+1.60+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2S5O12 by Materials Project

(Cs(SO3)2)2S crystallizes in the cubic P2_13 space group. The structure is three-dimensional and consists of four hydrogen sulfide molecules and one Cs(SO3)2 framework. In the Cs(SO3)2 framework, there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a distorted q4 geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.52–3.67 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.32–3.56 Å. There are two inequivalent S+4.40+ sites. In the first S+4.40+ site, S+4.40+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All S–O bond lengths are 1.79 Å. In the second S+4.40+ site, S+4.40+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.46–1.67 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one S+4.40+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one S+4.40+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Cs1+ and one S+4.40+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cs1+ and two S+4.40+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaH2Se(S2O3)2 by Materials Project

BaH2(SO3)2Se(S)2 crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of eight hydrogen sulfide molecules; four selenium molecules; and two BaH2(SO3)2 sheets oriented in the (0, 0, 1) direction. In each BaH2(SO3)2 sheet, Ba2+ is bonded in a 9-coordinate geometry to three H1+ and six O2- atoms. There are a spread of Ba–H bond distances ranging from 2.85–3.07 Å. There are a spread of Ba–O bond distances ranging from 2.71–2.80 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a bent 120 degrees geometry to two equivalent Ba2+ atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ atom. S1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of S–O bond distances ranging from 1.46–1.48 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S1+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiAuC4S4(OF)12 by Materials Project

LiAu(SO3)4(CF3)4 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of four fluoroform molecules and one LiAu(SO3)4 sheet oriented in the (0, 0, 1) direction. In the LiAu(SO3)4 sheet, Li1+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.13–2.34 Å. Au3+ is bonded in a square co-planar geometry to four O2- atoms. All Au–O bond lengths are 2.05 Å. There are two inequivalent S4+ sites. In the first S4+ site, S4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.44 Å) and one longer (1.53 Å) S–O bond length. In the second S4+ site, S4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of S–O bond distances ranging from 1.44–1.54 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Li1+ and one S4+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Au3+ and one S4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one S4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one S4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Au3+ and one S4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one S4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SmS3(NO3)3 by Materials Project

(Sm(SO3)3)2(N2)3 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional and consists of six ammonia molecules and one Sm(SO3)3 framework. In the Sm(SO3)3 framework, Sm3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are six shorter (2.42 Å) and three longer (2.57 Å) Sm–O bond lengths. S+0.67+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.46 Å) and two longer (1.47 Å) S–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Sm3+ and one S+0.67+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one S+0.67+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1981

Design, fabrication, and bench testing of a solar chemical receiver

Solar thermal energy can be effectively collected, transported, stored, and utilized by means of a chemical storage and transport system employing the reversible SO2 oxidation reaction. A solar chemical receiver for SO3 thermal decomposition to SO2 and oxygen was analyzed. Bench tests of a ten foot section of a receiver module were conducted with dissociated sulfuric acid (SO3 and H2O) in an electrical furnace. Measured percent conversion of SO3 was 85% of the equilibrium value. Methods were developed to fabricate and assemble a complete receiver module. These methods included applying an aluminide coating to certain exposed surfaces, assembling concentric tubes with a wire spacer, applying a platinum catalyst to the tubing wall, and coiling the entire assembly into the desired configuration.

Summers, W. A.↗
NASA NTRS1984

Studies of proton-irradiated SO2 at low temperatures Implications for Io

The infrared absorption spectrum from 3.3 to 27 microns of SO2 ice films has been measured at 20 and 88 K before and after 1-MeV proton irradiation. The radiation flux was chosen to simulate the estimated flux of Jovian magnetospheric 1-MeV protons incident on Io. After irradiation, SO3 is identified as the dominant molecule synthesized in the SO2 ice. This is also the case after irradiation of composite samples of SO2 with sulfur or disulfites. Darkening was observed in irradiated SO2 ice and in irradiated S8 pellets. Photometric and spectral measurements of the thermoluminescence of irradiated SO2 have been made during warming. The spectrum appears as a broad band with a maximum at 4450 A. Analysis of the luminescence data suggests that at Ionian temperatures irradiated SO2 ice would not be a dominant contributor to posteclipse brightening phenomena. After warming to room temperature, a form of SO3 remains along with a sulfate and S8. Based on these experiments, it is reasonable to propose that small amounts of SO3 may exist on the surface of Io as a result of irradiation synthesis in SO2 frosts.

Moore, M. H.↗
NASA NTRS2003

Sulfur Oxidation and Contrail Precursor Chemistry

Sulfuric acid (H2SO4), formed in commercial aircraft operations via fuel-S (goes to) SO2 (goes to) SO3 (goes to) H2SO4 plays an important role in the formation of contrails. It is believed that the first step occurs inside the combustor, the second step in the engine exit nozzle, and the third step in the exhaust plume. Thus, measurements of the sulfur oxidation rates are critical to the understanding of contrail formation. Field measurements of contrails formed behind commercial aircraft indicate that significantly greater conversion of fuel-bound sulfur to sulfate aerosol occurs than can be explained by our current knowledge of contrail physics and chemistry. The conversion of sulfur from S(IV) to S(VI) oxidation state, required for sulfate aerosol formation, is thermodynamically favored for the conditions that exist within jet engines but is kinetically disfavored. The principal reaction pathway is O+SO2+M (goes to) SO3+M. The rates of this reaction have never been measured in the temperature and pressure regimes available to aircraft operation. In the first year (FY02) of this project, we performed a series of experiments to elucidate the rate information for the O+SO2+M (goes to) SO3+M reaction. The work performed is described following the proposed work plan. Because we used the H2/O2 system for an O-atom source and rate coefficients were obtained via computer simulation, construction of a reaction mechanism and either recalculation or estimation of thermodynamic properties of H(x)SO(y) species are described first.

DeWitt, Kenneth J.↗
NASA NTRS2005

Sulfur Oxidation and Contrail Precursor Chemistry

Sulfuric acid (H2SO4), formed in commercial aircraft operations via Fuel-S (right arrow) SO2 + SO3 (right arrow) H2SO4, plays an important role in affecting the global climate change through atmospheric chemical reactions and radiative forcing. Measurement of the sulfur oxidation rates is critical to the understanding of the contrail formation. The principle reaction pathway is SO2 + O + M (right arrow) SO3 + M. Although there are many measurements for the rates of this reaction, it has never been measured in the temperature and pressure regime available to aircraft operation. In this investigation, a series of experiments were performed behind the reflected shock waves in a shock tube. OH radicals were produced in lean, shock heated SO2/H2/O2/Ar mixtures. The reaction progress was followed using OH absorption spectroscopy at 310 nm. The data were analyzed with the aid of computer modeling/simulation. The mean value of the rate coefficients of R21 determined is k(sub 21,0)/[M]= 3.9 x 10(exp 15) cm(sup 6) per square mole per second at T = 960 - 1150 K and rho = 16-30 micromole per cubic centimeter with uncertainty limits of plus or minus 30%. A non-Arrhenius fit to our data together with all existing data gives k(sub 21,0)/[M] = 1.3 x 10(exp 24) T (exp -2.5) exp(-2350 K/T) cm(sup 6) per square mole per second at T = 300 - 2500 K with the same uncertainty limits given above. The calculated conversion of S(IV)(SO2) to S(VI) (SO3 + H2SO4) was about 2% in our experimental conditions.

DeWitt, Kenneth↗
NASA NTRS2014

Solar Metal Sulfate-Ammonia Based Thermochemical Water Splitting Cycle for Hydrogen Production

Two classes of hybrid/thermochemical water splitting processes for the production of hydrogen and oxygen have been proposed based on (1) metal sulfate-ammonia cycles (2) metal pyrosulfate-ammonia cycles. Methods and systems for a metal sulfate MSO.sub.4--NH3 cycle for producing H2 and O2 from a closed system including feeding an aqueous (NH3)(4)SO3 solution into a photoctalytic reactor to oxidize the aqueous (NH3)(4)SO3 into aqueous (NH3)(2)SO4 and reduce water to hydrogen, mixing the resulting aqueous (NH3)(2)SO4 with metal oxide (e.g. ZnO) to form a slurry, heating the slurry of aqueous (NH4)(2)SO4 and ZnO(s) in the low temperature reactor to produce a gaseous mixture of NH3 and H2O and solid ZnSO4(s), heating solid ZnSO4 at a high temperature reactor to produce a gaseous mixture of SO2 and O2 and solid product ZnO, mixing the gaseous mixture of SO2 and O2 with an NH3 and H2O stream in an absorber to form aqueous (NH4)(2)SO3 solution and separate O2 for aqueous solution, recycling the resultant solution back to the photoreactor and sending ZnO to mix with aqueous (NH4)(2)SO4 solution to close the water splitting cycle wherein gaseous H2 and O2 are the only products output from the closed ZnSO4--NH3 cycle.

Huang, Cunping↗
NASA NTRS2016

Igneous and Sedimentary Compositions from Four Landing Sites on Mars from the Alpha Particle X-Ray Spectrometer (APXS)

The APXS - supported and promoted strongly by Heinrich Waenke - on all four Mars Rovers has returned compositional data from about 1000 rocks and soil targets along the combined traverses of over 60 kilometers. Providing precise and accurate bulk chemistry with typically 16 quantified elements, the APXS is a powerful and versatile tool that when combined with the ability to traverse to key rocks and soils has provided critical information needed to understand the geologic evolution of Mars. APXS data allow comparisons among landing sites, provide ground truth for orbiters and connections back to SNC meteorites. The soils and dust are basaltic in character and represent the average Mars composition similar to Adirondack basalts from Gusev crater but with unambiguous elevated and correlated S, Cl and Zn contents. At all four landing sites the APXS found several rocks with a felsic composition. The similarity is best assessed in a logarithmic ratio plot of rock normalized to the average soil composition (Fig.1). High alkaline, Al, and low Mg, Fe, low S, Cl and Ni, Zn as well as an Fe/Mn ratio of approximately 50 indicate a likely unaltered and igneous origin. Sediments, e.g. the Burns formation, with approximately 25 wt% SO3 at Meridiani Planum have been documented over 10s of kilometers (Fig. 2). This formation is compositionally homogeneous, but showing the removal of MgSO4 and a threefold increase in Cl downhill in 2 craters. The degraded rim of the Noachian crater Endeavour resembles average Mars crust, with local Ca, Mg and Fe sulfate alteration and elevated Mn, some felsic rocks, and high Al, Si and low Fe rocks, possibly indicating clays. Unusual soils at Gusev crater in the area surrounding Home Plate include some very rich in ferric sulfate salts (up to 35 wt% SO3) and some with 90% wt% SiO2, possibly indicating fumerolic activities. Rocks in the Columbia Hills show significant signs of alteration including elevated S, Cl and Br in the abraded interior. At Gale Crater, mudstones with approximately 20% clay, less than 1% SO3 and overall average Mars composition indicate a former habitable environment with low acidity. A remarkable diversity of compositions was found during Curiosity's traverses, which likely stems from material influx from the northern Gale rim. At Pahrump, the base of Mount Sharp, a homogeneous mudstone with lower Mg and Ca was encountered. The composition of this Murray unit can be traced over several kilometers with smooth trends of higher Fe/Mn and lower soluble trace elements Ni and Zn at higher elevation. The likely aeolian Stimson formation with average Mars crustal composition intersects in several places in sharp contact with the Murray formation. Both units show local alteration halos with highly elevated SiO2 of up to 75%, usually correlated with increase in Ti and often P.

Gellert, R.↗
DOE OSTI2020

Thermal Properties of Sodium Borosilicate Glasses as a Function of Sulfur Content

SO3 additions, up to 3.0 wt%, were systematically investigated for effects on the physical properties of sodium borosilicate glass melted in air, with a sulfur-free composition of 50SiO2-10Al2O3-12B2O3-21Na2O-7CaO (wt%). Solubility measurements, using electron microscopy chemical analysis, determined the maximum loading to be ~1.5 wt% SO3. It was found that sulfur (here as sulfate) in this glass increased the glass transition temperature, thermal diffusivity, heat capacity, and thermal conductivity, and decreased the mass density. Structural analysis, performed with Raman spectroscopy, indicated that the borosilicate network polymerized with sulfur additions, presumably due to Na2O being required to charge compensate the ionic SO42- additions, thus becoming unavailable to form non-bridging oxygen in the silicate network. It is postulated that this increased crosslinking of the borosilicate backbone lead to a structure with higher dimensionality and average bond energy. This increased the mean free paths and vibration frequency of the phonons, which resulted in the observed increase in thermal properties.

Thermal properties, Borosilicate glass, Sulfur sol↗
DOE OSTI2020

Materials Data on ZnC2S2(OF)6 by Materials Project

Zn(CF3SO3)2 crystallizes in the trigonal R-3 space group. The structure is two-dimensional and consists of six fluoroform molecules and three Zn(SO3)2 sheets oriented in the (0, 0, 1) direction. In each Zn(SO3)2 sheet, Zn2+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Zn–O bond lengths are 2.11 Å. S4+ is bonded in a trigonal non-coplanar geometry to three equivalent O2- atoms. All S–O bond lengths are 1.46 Å. O2- is bonded in a distorted bent 150 degrees geometry to one Zn2+ and one S4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuC2S2(OF)6 by Materials Project

Cu(CF3SO3)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of two fluoroform molecules and one Cu(SO3)2 sheet oriented in the (0, 0, 1) direction. In the Cu(SO3)2 sheet, Cu2+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Cu–O bond distances ranging from 1.99–2.40 Å. S4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.44 Å) and two longer (1.48 Å) S–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Cu2+ and one S4+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu2+ and one S4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cu2+ and one S4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(SO4)2 by Materials Project

BaS2O8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional and consists of four hydrogen peroxide molecules and one Ba(SO3)2 framework. In the Ba(SO3)2 framework, Ba is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ba–O bond distances ranging from 2.63–2.81 Å. S is bonded in a trigonal non-coplanar geometry to three O atoms. All S–O bond lengths are 1.47 Å. There are three inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Ba and one S atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Ba and one S atom. In the third O site, O is bonded in a distorted single-bond geometry to one Ba and one S atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

A Novel Dew Point Meter: Application to the Measurement of the Sulfuric Acid Dew Point for Combustion Flue Gas

Accurate knowledge of acid dew point is essential for industrial and applied combustion applications. Sulfur in the fuel or raw materials is converted to sulfur dioxide (SO2) during combustion, and a portion of the SO2 is oxidized to sulfur trioxide (SO3). The SO3 will react to form H2SO4 vapor when in the presence of water vapor. Even with just trace levels of H2SO4 vapor in the gas phase (1-10 ppm), the dew point can reach 100°C and higher. To avoid acid condensation and the resulting corrosion on heat recovery equipment, plant engineers must ensure that surface temperatures are above the acid dew point, but this decreases the efficiency of thermal energy recovery. Thus, there is a trade-off between minimizing equipment corrosion and maximizing thermal energy recovery, and the acid dew point is a key parameter for this optimization. Commercially available acid dew point meters use electric conductivity sensors. These sensors are known to greatly underestimate the dew point due to their low sensitivity. In addition, no validation testing has been reported for these units and they are often expensive. In this work, we analyze the theory of the sulfuric acid condensation and develop a novel dew point meter based on this analysis. The meter consists of a novel optical instrument that is designed to monitor the slightest appearance of condensation on a hydrophobic window surface as the surface temperature of the window is slowly decreased. In this way, an accurate measurement of the dew point is obtained under a wide range of concentrations. The basis of the instrument is that a collimated beam from a diode laser will generate forward scattered light when the beam encounters surface condensate, and a sophisticated array detector is used to sensitively monitor the onset of light scattering. The measurement procedures are established to rapidly find the acid dew point, while minimizing error. Further, to calibrate the dew point meter we developed a calibration system based on a liquid bubbler that can generate a stable gas flow with a known sulfuric acid dew point. Test results show that the dew point meter can accurately measure acid dew point over a wide range. For H2SO4 vapor concentrations as low as 6 ppm the acid dew point is measured with an error of only ~1°C. To demonstrate the versatility of this instrument, the dew point meter was adapted for use with a high-pressure flow cell to allow for measurements of the dew point of flue gas from pressurized oxy-fuel combustion in a 100 kWth pressurized reactor.

Cheng, Mao↗