Chemistry: analytical and immunological testing – Sulfur containing
Patent
1988-04-07
1990-12-11
Hastings, Karen M.
Chemistry: analytical and immunological testing
Sulfur containing
436120, 436121, 436128, 436175, G01N 2178, G01N 3122
Patent
active
049770934
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This patent is directed to the field of detection of trace impurities in gases and particularly to a portable analyzer and process for the detection of carbonyl sulfide present in low part-per-million and part-per-billion concentrations in gases such as carbon dioxide gas.
2. Description of the Prior Art
Carbon dioxide gas is extensively used in the soft drink as well as the beer industries. Even very small amounts of carbonyl sulfide while odorless itself produces off-flavors in the food products in which the carbon dioxide contaminated with carbonyl sulfide is used. It is very difficult to detect low part-per-million (PPM) and part-per-billion (PPB) concentrations of carbonyl sulfide (COS) in gases such as carbon dioxide (CO.sub.2).
It is desirable in the beverage industry to have an extremely accurate carbonyl sulfide analyzer which is inexpensive, portable, and extremely accurate to the extent of detecting carbonyl sulfide in carbon dioxide of less than 1 PPM.
One method for detecting carbonyl sulfide in gases is by means of a color tube produced by Bendix. This tube is based on an acid-base system which converts the carbonyl sulfide to sulfuric acid. The presence of carbonyl sulfide is indicated by a color change. The sensitivity of this test is not very good since the smallest amount of carbonyl sulfide which can be detected is 10 PPM. Moreover, it is not suitable for the detection of carbonyl sulfide in carbon dioxide because the carbon dioxide also reacts in the color tube.
Another means for detection of carbonyl sulfide is the use of a flame photometric detector (FPD). This device attaches to a gas chromatograph and is very accurate. The main drawbacks are that it is extremely costly, large in size, and requires a source of hydrogen and air as a fuel and nitrogen as a carrier gas.
SUMMARY OF THE INVENTION
The present invention provides a portable, lightweight analyzer to detect carbonyl sulfide in a gas which is light in weight and relatively low in cost when compared with prior art devices. Furthermore, it is extremely accurate to the extent of detecting carbonyl sulfide in carbon dioxide in concentrations as low as 0.05 PPM (50 PPB).
A process for the detection of carbonyl sulfide in a gas such as carbon dioxide is also provided. The process comprises providing a known volume of gas to be analyzed and removing any hydrogen sulfide from the gas. The carbonyl sulfide is then converted to hydrogen sulfide which is then detected and measured. The amount of hydrogen sulfide detected represents an equimolar amount of carbonyl sulfide present in the original volume of gas.
The portable, lightweight analyzer of the invention comprises means for providing a known volume of gas to be analyzed: means for removing hydrogen sulfide from the gas: means for converting the carbonyl sulfide in the gas volume to hydrogen sulfide: means for detecting and measuring the hydrogen sulfide in the gas: and conduit means for connecting the means together.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of the process steps of the invention: and,
FIG. 2 shows a schematic representation of the portable analyzer of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The Process
Referring now to the block diagram of FIG. 1, there are shown the process steps of the invention. The first step in the process comprises providing a known volume of gas to be analyzed. This is indicated in block 1 of FIG. 1. A known volume of gas is necessary to determine the concentration of the carbonyl sulfide in the gas to be analyzed.
The next step shown in block 2 comprises removing any hydrogen sulfide (H.sub.2 S) from the known volume of gas. The presence of H.sub.2 S in the gas prior to analysis would interfere with the carbonyl sulfide determination and, thus, must be removed. This can be accomplished in any convenient manner. Preferably the gas is brought into contact with one or more chemicals which will react with the H.sub.2 S but which are substantially unrea
REFERENCES:
patent: 2174349 (1939-09-01), Littlefield
patent: 3300282 (1967-01-01), Risk et al.
patent: 3607073 (1971-09-01), Stamm
patent: 3725009 (1973-04-01), Lovelock
patent: 3756781 (1973-09-01), Kimbell
patent: 3853474 (1974-12-01), Austin
patent: 4120659 (1978-10-01), Cropper
patent: 4238198 (1980-12-01), Swaim et al.
patent: 4332781 (1982-06-01), Leider et al.
patent: 4352779 (1982-10-01), Parks
patent: 4359450 (1982-11-01), Blytas et al.
patent: 4472977 (1983-11-01), Fisch
Tilk, "The Determining of Organic Sulfur in Gases by the Catalytic Hydrolysis Method" Proc. of 42nd Annual Mtg. of Amer. Soc. for Testing Materials, 1939, vol. 39, pp. 1159-1170
Bethel George F.
Bethel Patience K.
Hastings Karen M.
Liquid Air Corporation
Miles Laura
LandOfFree
Process for analyzing carbonyl sulfide in a gas does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for analyzing carbonyl sulfide in a gas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for analyzing carbonyl sulfide in a gas will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-389888