scholarly journals Water vapor inhibits hydrogen sulfide detection in pulsed fluorescence sulfur monitors

2016 ◽  
Vol 9 (6) ◽  
pp. 2669-2673 ◽  
Author(s):  
Anders B. Bluhme ◽  
Jonas L. Ingemar ◽  
Carl Meusinger ◽  
Matthew S. Johnson
Keyword(s):  
Hydrogen Sulfide ◽  
Water Vapor ◽  
Sulfur Dioxide ◽  
Relative Humidity ◽  
Pollution Control ◽  
Sulfide Sulfur ◽  
Molybdenum Catalyst ◽  
Air Stream ◽  
Ambient Concentrations ◽  
Converter Unit

Abstract. The Thermo Scientific 450 Hydrogen Sulfide–Sulfur Dioxide Analyzer measures both hydrogen sulfide (H2S) and sulfur dioxide (SO2). Sulfur dioxide is measured by pulsed fluorescence, while H2S is converted to SO2 with a molybdenum catalyst prior to detection. The 450 is widely used to measure ambient concentrations, e.g., for emissions monitoring and pollution control. An air stream with a constant H2S concentration was generated and the output of the analyzer recorded as a function of relative humidity (RH). The analyzer underreported H2S as soon as the relative humidity was increased. The fraction of undetected H2S increased from 8.3 at 5.3 % RH (294 K) to over 34 % at RH  >  80 %. Hydrogen sulfide mole fractions of 573, 1142, and 5145 ppb were tested. The findings indicate that previous results obtained with instruments using similar catalysts should be re-evaluated to correct for interference from water vapor. It is suspected that water decreases the efficiency of the converter unit and thereby reduces the measured H2S concentration.

scholarly journals Water Vapor Inhibits Hydrogen Sulfide Detection in Pulsed Fluorescence Sulfur Monitors

2016 ◽  
Author(s):  
Anders B. Bluhme ◽  
Jonas L. Ingemar ◽  
Carl Meusinger ◽  
Matthew S. Johnson
Keyword(s):  
Hydrogen Sulfide ◽  
Water Vapor ◽  
Sulfur Dioxide ◽  
Relative Humidity ◽  
Pollution Control ◽  
Sulfide Sulfur ◽  
Molybdenum Catalyst ◽  
Air Stream ◽  
Ambient Concentrations ◽  
Converter Unit

Abstract. The Thermo Scientific 450 Hydrogen Sulfide - Sulfur Dioxide Analyzer measures both H2S and SO2. SO2 is measured by pulsed fluorescence, while H2S is converted to SO2 with a molybdenum catalyst prior to detection. The 450 is widely used to measure ambient concentrations, e.g. for emissions monitoring and pollution control. An air stream with a constant H2S concentration was generated and the output of the analyzer recorded as a function of relative humidity. The analyzer under-reported H2S as soon as the relative humidity was increased. The fraction of undetected H2S increased from 8.3 % at 5.3 % RH (294 K) to over 34 % at RH > 80 %. H2S mole fractions of 573, 1142, and 5145 ppb were tested. The findings indicate that previous results obtained with instruments using similar catalysts should be re-evaluated to correct for interference from water vapor. It is suspected that water decreases the efficiency of the converter unit and thereby reduces the measured H2S concentration.

The Interaction of Sulfur and Sulfur Compounds with Olefinic Substances. VII. Low-Temperature Sulfuration of Trialkylethylenes with Hydrogen Sulfide-Sulfur Dioxide and with a Sulfur-Zinc Dithiocarbamate System

1955 ◽  
Vol 28 (2) ◽  
pp. 470-479
Author(s):  
E. H. Farmer ◽  
J. F. Ford ◽  
J. A. Lyons
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Low Temperature ◽  
Room Temperature ◽  
Cross Linking ◽  
Sulfide Sulfur ◽  
Tetramethylthiuram Disulfide ◽  
Zinc Compounds ◽  
Low Concentrations

Abstract The sulfuration of trialkylethylenes with hydrogen sulfide-sulfur dioxide at 0° C (Peachey process) results in disubstitutive cross-linking of the olefins, yielding dialkenyl tetrasulfides. At higher temperatures, substitutive-additive cross-linking occurs, and alkyl alkenyl polysulfides are formed. Dialkenyl tetrasulfides are similarly formed by causing the olefin to react with sulfur at room temperature in the presence of zinc oxide and zinc dibutyldithiocarbamate, low concentrations of hydrogen sulfide acting as a catalyst for this reaction. At higher temperatures, the reaction is also exclusively disubstitutive, a feature connected with the function of zinc compounds in influencing the cross-linking reaction. The sulfuration of olefins with tetramethylthiuram disulfide at 140° C shows a similar influence of zinc compounds.

Vulcanization of GR-S by the Peachey Process

1947 ◽  
Vol 20 (1) ◽  
pp. 182-183
Author(s):  
Archibald T. McPherson
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfur Dioxide ◽  
Natural Rubber ◽  
Glass Tube ◽  
The Other ◽  
Curing Process ◽  
Sulfide Sulfur ◽  
Simple Apparatus ◽  
Synthetic Rubber

Abstract It has been found possible to vulcanize GR-S synthetic rubber by subjecting it alternately to hydrogen sulfide and sulfur dioxide gases. This method for curing, known as the Peachey process, was used for natural rubber as long ago as 1921. A simple apparatus was constructed, in which strips of thinly milled rubber were placed on a screen inside a glass tube. One end of this tube was attached to valves connecting it to tanks of hydrogen sulfide, sulfur dioxide, and air, respectively. The other end of the tube led to a series of traps containing solutions which absorbed or destroyed the gases. For each test performed, natural rubber samples were placed inside the tube along with the GR-S samples for comparison. Each strip was weighed before it was inserted in the apparatus. Hydrogen sulfide was first slowly passed over the samples for a period of five minutes. Then air was blown through for a few seconds—just long enough to free the surroundings from the sulfide gas, but not long enough for the gas to be lost from solution in the rubber. Sulfur dioxide gas was next admitted and allowed to pass over the samples for five minutes. A subsequent short sweep of air through the tube completed one cycle of the curing process.

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