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Designation: D — 02 Reapproved Standard Test Method for. A number in parentheses indicates the y ear of last rea pp roval. Other methods have been used to perform this analysis. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use.
Ref erenced Documents. Current edition approved May 15, Published June Originally approved in Last previous edition approved in as D — 02 Oil-Immersed Transformers 3. Publication No. In Methods B and C, the sum of the individual gas concentra- tions corrected to torr The vessel is a headspace vial of mL nominal capacity. The last approved version of this historical standard is referenced on www. D — 02 Summary of Test Method. The evolved gases are compressed to atmo- spheric pressure and the total volume measured.
The gases contained in the loop are then introduced into a gas chromato- graph. Calibra- tion curves are used in Method C to establish the concentration.
The composition of the sample is calculated from its chromatogram by comparing the area of the peak of each component with the area of the peak of the same component on a reference chromatogram made on a standard mixture of known composition. The nature and amount of the individual component gases that may be recovered and analyzed may be indicative of the type and degree of the abnormality responsible for the gas generation.
For Ace Glass, the glass apparatus conforming to Fig. Available from P. Box , Northwest Blvd. N OTE 2—This sample size has been found to be sufficient for most oils. However, oil that has had only limited exposure to air may contain much smaller amounts of nitrogen and oxygen.
For these oils it may be desirable to increase the size of the sample and the extraction apparatus. N OTE 3—Alternative apparatus designs including the use of a Toepler pump have also been found successful. A suitable arrangement is shown in Fig.
Warning —Mercury vapor is ex- tremely toxic. Appropriate precautions should be taken. The use of rigid metal cylinders is not recommended for use with Method B. It is also important that the quantity and composition of dissolved gases remain unchanged during transport to the laboratory.
Avoid prolonged exposure to light by immediately placing drawn samples into light-proof containers and retaining them there until the start of testing. Evaluate containers for maximum storage time. Samples have been stored in syringes and metal cylinders for four weeks with no appreciable change in gas content. Method A—Vacuum Extraction. The evolved gases are compressed to.
Ostwald coefficients for mineral oils of different density may be calculated as follows:. This equation is derived from the equation in Test Method D Note especially that all of the Ostwald coefficients are changed by the same factor, meaning that though the absolute solubilities of each of the gases will change if a different oil is used, the ratio of the solubility of one gas to another gas will remain constant.
The methods of preparation are outlined in Annex A1 and Annex A2. The gases are then analyzed by gas chromatography. Preparation of Apparatus. V T , and the volume of the collection space, V c , and calculate. Values for gases in other oils may be estimated by reference to Test Method D Component Gas. Carbon monoxide. Carbon dioxide. In Fig. This may be accom-. This is the volume, V o used in the calculation in Correct to torr.
Record the gas content as a percentage of the oil by volume. The extractor can be rinsed with oil containing nondetectable quantities of gases, except for those present in air. The amount of rinsing needed will be dependent upon the gas concentration, type solubility in oil , and efficiency of the extractor.
To ensure that the combustible gases have been sufficiently removed from the extractor, the rinse oil may be treated as a sample. General rinse procedures may be established. However, for samples with very high concentra- tions of gases, verify effectiveness of the rinse procedure. Carbon oxides.
Atmospheric gases. Both argon and helium have been used as carrier gases see Note 7. N OTE 7—If helium is used as a carrier gas with a thermal conductivity detector, medium to high concentrations of hydrogen may give a nonlinear response, due to the closed heat capacity values of helium and hydrogen. The limit of detection will be higher than with an argon carrier gas under similar conditions. If nitrogen is used as a carrier gas, nitrogen cannot be detected in the sample.
The condition of the nickel catalyst can be evaluated by checking the linearity of the. With helium as a carrier gas, a catalytic converter is not necessary but may be used to enhance sensitivity. A wide range of injector, column, and detector temperatures can be used.
Both isothermal and temperature programs can be used to provide adequate separation and sensitivity. A typical chro- matogram is shown in Fig. Reagent and Materials. Unless otherwise indicated, it is intended that. It is strongly recommended that only primary standards each component prepared gravimetri-. Refer to Practice D for procedures used to prepare a blend of standard gases. However, in most samples the concentration of gases except oxygen, nitrogen, and carbon dioxide is tens to hundreds of parts per million.
Normally, the gas standard is prepared at concentra- tions of 5 to 10 times that seen in the oil due to the concentration effect of extracting the gas from the oil and because higher concentrations can be prepared with greater. Pharmacopeial Convention, Inc. USPC , Rockville,. Department of Commerce, National Institute of Standards. Gas Chromatograph Conditions:. Catalytic converter for detection of CO and CO 2.
Thermal conductivity: H 2 , O 2 , N 2. N OTE 1—Propane and propylene are not separated under these conditions. Some laboratories use more than one concentration of standards. Acetylene is of greater concern at lower concen- tration levels than the other hydrocarbon gases. Repeat the analysis until consistent operating. Repeat calibration daily when analyses are being con- ducted. Procedure Adjust the gas pressure,.
The frequency and duration will depend upon such factors as type of column, amount of use, and concentration of materials tested. Peaks which are not as sharp as usual may be from compounds retained on the column from a previous run, and may indicate a need for baking out the columns. Another indicator that the molecular sieve column needs conditioning is that the methane and carbon monoxide peaks begin to lose baseline separation.
Correct to torr Temperature of oil at time of sampling,. Gas content of oil by volume, expressed as a per-. Volume concentration in the oil, for each component. Precision and Bias. Method A have been evaluated by a statistical examination of the results of an inter-laboratory test of mineral oil test.
Designation: D — 02 Reapproved Standard Test Method for. A number in parentheses indicates the y ear of last rea pp roval. Other methods have been used to perform this analysis. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. Ref erenced Documents. Current edition approved May 15,
An Improved ASTM D3612 TOGAS System
Historical Version s - view previous versions of standard. Work Item s - proposed revisions of this standard. More D The nature and amount of the individual component gases that may be recovered and analyzed may be indicative of the type and degree of the abnormality responsible for the gas generation. The rate of gas generation and changes in concentration of specific gases over time are also used to evaluate the condition of the electric apparatus.
A novel technology for transformer oil gas analysis using a stripper column (ASTM D3612)
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