Impurities in Gases

Particulate composites, 26 754-755 ceramics processing, 5 653-654 extensional modulus of, 26 777 fabrication of, 26 766 Particulate emission limits, 13 183 Particulate emissions, reducing, 11 689 Particulate fillers, ll 302t, 303 for rubber, 21 772, 773 Particulate fluidized-bed regime, 11 801 Particulate impurities in gases, 13 464 in high purity gases, 13 466 Particulate matter (PM), 1 798-801 ... 

Fully commercial In natural gas and refinery applications. Feed impurities In gases from synfuel plants can create problems... 

M.P. Gorshkov, Analysis of Impurities in Gases, Inventor s Certificate of USSR No 966583, G01N27/62 (1982). 

In the case of evaluation of the detection limit of gaseous impurities in gases, particularly in air, the amount of the detected or determined substances is usually given in volumetric units such as milliliters per cubic meter (mL/m ), which is equivalent to ppm (volumetric). Presentation of the content of gaseous components in mass units (mg/m ) is less convenient, because it depends on temperature and pressure and should be given under standard conditions (e.g., 20 °C, 1013 mbar). 

Later, a similar technique was used for concentrating acid impurities in gases on triethanolamine [123] the lowest concentration under test was ca. 10 %. The application of chemical concentration, compared with the conventional sorption method, ensures... 

Thermodynamic description of minor impurities in gases or minor carrier in electrolyte. 

Yokokawa H, Yamaji K, Brito ME, Kishimoto H, Horita T (2011) General considerations on degradation of SOFC anodes and cathodes to impurities in gases. J Power Sources 196 7070-7075... 

Typical concentrations of major components and impurities in gases derived from coal are given in Table 4-4. The principal impurities removed by coal-gas purification processes are hydrogen sulfide and ammonia. These compounds are undesirable because they can cause corrosion, plugging, and ultimately, air pollution. In addition, both H2S and NH3 are relatively valuable chemicals, and their recovery and conversion to useful products, such as elemental sulfur and ammonia, can be of significant economic value. This was particularly true... 

Kambara, H. Kanomata, 1. Determination of impurities in gases by atmospheric pressure ionization mass spectrometry. A af Chem. 1977, 49, 270-275. 

A comparison between the filtering and impinger techniques for the determination of particulate metal impurities in gases has been performed using NaCl particles. The recovery... 

Suzuki, I. and Tarutani, K. (1997) Comparison of sampling techniques for the analysis of particulate metal impurities in gases. Anal. Sci, 13(10), 833-6. 

The elimination of particulate impurities in gases is critical in order to prevent the introduction of these impurities into vapour-deposited thin films, silicon substrate surfaces and silicon crystal lattices. Incorporation of gas-derived particulates and metallic contaminants often leads to crystallographic defects. These defects can... 

The deterrnination of impurities in the hehum-group gases is also accompHshed by physical analytical methods and by conventional techniques for measuring the impurity in question (93), eg, galvanic sensors for oxygen, nondispersive infrared analysis for carbon dioxide, and electrolytic hygrometers for water. 

The gases leaving the purification system are scmbbed with water to recover solvent and a continuous small purge of solvent gets rid of polymers. The acetylene purity resulting from this system is 99%. The main impurities in the acetylene are carbon dioxide, propadiene, and a very small amount of... 

Processing variables that affect the properties of the thermal CVD material include the precursor vapors being used, substrate temperature, precursor vapor temperature gradient above substrate, gas flow pattern and velocity, gas composition and pressure, vapor saturation above substrate, diffusion rate through the boundary layer, substrate material, and impurities in the gases. Eor PECVD, plasma uniformity, plasma properties such as ion and electron temperature and densities, and concurrent energetic particle bombardment during deposition are also important. 

Chemical Applications. Cesium metal is used in carbon dioxide purification as an adsorbent of impurities in ferrous and nonferrous metallurgy (qv) it can be used as a scavenger of gases and other impurities. 

Typical applications in the chemical field (Beaver, op. cit.) include detarring of manufactured gas, removal of acid mist and impurities in contact sulfuric acid plants, recovery of phosphoric acid mists, removal of dusts in gases from roasters, sintering machines, calciners, cement and lime Idlns, blast furnaces, carbon-black furnaces, regenerators on fluid-catalyst units, chemical-recoveiy furnaces in soda and sulfate pulp mills, and gypsum kettles. Figure 17-74 shows a vertical-flow steel-plate-type precipitator similar to a type used for catalyst-dust collection in certain fluid-catalyst plants. 

Few mechanisms of liquid/liquid reactions have been established, although some related work such as on droplet sizes and power input has been done. Small contents of surface-ac tive and other impurities in reactants of commercial quality can distort a reac tor s predicted performance. Diffusivities in liquids are comparatively low, a factor of 10 less than in gases, so it is probable in most industrial examples that they are diffusion controllech One consequence is that L/L reactions may not be as temperature sensitive as ordinary chemical reactions, although the effec t of temperature rise on viscosity and droplet size can result in substantial rate increases. L/L reac tions will exhibit behavior of homogeneous reactions only when they are very slow, nonionic reactions being the most likely ones. On the whole, in the present state of the art, the design of L/L reactors must depend on scale-up from laboratoiy or pilot plant work. 

The paper describes the different chemical sensors and mathematical methods applied and presents the review of electronic tongue application for quantitative analysis (heavy metals and other impurities in river water, uranium in former mines, metal impurities in exhaust gases, ets) and for classification and taste determination of some beverages (coffee, bear, juice, wines), vegetable oil, milk, etc. [1]. 

Katharometer A device that compares the thermal conductivity of two gases, used to detect the presence of impurities in air. 

The noble gases make up about 1% of the earth s atmosphere in which their major component is At. Smaller concentrations are occluded in igneous rocks, but the atmosphere is the principal commercial source of Ne, Ar, Kr and Xe, which are obtained as by-products of the liquefaction and separation of air (p. 604). Some Ar is also obtained from synthetic ammonia plants in which it accumulates after entering as impurity in the N2 and H2 feeds. World production of... 

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