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Apparatus for analyzing natural gas-Continued.

Qualitative tests for carbon monoxide and olefin hydrocarbons in

natural gas.

Calculations from combustion data--------

Reactions of methane and ethane with oxygen -------

Molecular volume of carbon dioxide at different partial pres-

sures-----------

Application of the use of corrected equations to the analyses

of natural gas and other gas mixtures--------

Analysis of gas containing high percentages of CO-----

Analysis of methane_-

Analysis of ethane--------

Correction for other gases.

----------------

Determination of hydrogen sulphide in natural gas-----

Determination of oxygen in natural gas_.

Use of alkaline pyrogallate---

Use of phosphorus --------

Importance of determining oxygen.

Manganous hydroxide method.

Analysis of small sample_-----

Heating value of natural gas.-----------

Liquefaction and fractionation of natural gas

Natural gas used at Pittsburgh------

Fractionation of paraffins-------

Constituents of Pittsburgh natural gas----

Test for gasoline content of natural gas..

Relative effects of solvents--------------

Determination of density of natural gas..

Weight method ----

Calculation ----

Properties of the more common paraffin hydrocarbons.

Summary ----

Publications on analysis of mine gases---

Index --------

ILLUSTRATIONS

Plate I. Sling psychrometer-----

II. Laboratory form of apparatus for exact analysis of mine air.

III. Diagram of laboratory form of apparatus for exact analysis

of mine air------

---------

IV. Haldane gas-analysis apparatus -------

V. Copper oxide apparatus for complete analysis of gases-----
VI. Standards and apparatus for determining percentage of

saturation of carbon monoxide in blood, and the analysis of
mine-air samples for carbon monoxide content, by pyro-
tannic acid method.---

----
VII. Laboratory type of interferometer.
VIII. Apparatus for fractionation of natural gas at low tempera-

tures and pressures----

Figure 1. Shipping box containing vacuum bulbs------

2. Glass tubes for taking samples by water displacement -----

3. Curves of equal relative humidity for varying temperatures

and depressions of wet bulb..

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Figure 4. Curves of equal relative humidity for varying temperatures

and volumes of water carried

5. Apparatus for determination of moisture in gas mixtures ---

6. Laboratory apparatus for exact determination of methane--

7. Portable apparatus for determination of methane in mine air--

8. Portable apparatus for determination of carbon dioxide and

methane in mine air-------

9. Modified Orsat gas-analysis apparatus.

10. Copper oxide apparatus for complete analysis of gases_----

11. Orsat apparatus for complete analysis of gases which do not

contain ethane or other higher saturated hydrocarbons_-----

12. Details of standard burette, model C-------

13. Details of combustion pipette for Orsat apparatus.

14. Details of copper oxide. tube------

15. Manifold for Orsat apparatus ----

16. Electric heater for copper oxide tube_---

17. Blower for combustion pipette--------

18. Wooden support for Orsat apparatus.

19. Gas-heated mercury still-----

20. Electrically heated mercury still.---------

21. Container for gases---

22. Apparatus for determination of carbon monoxide by means of

iodine pentoxide_-

23. Iodine pentoxide apparatus for determination of carbon mon-

oxide, using liquid air to remove impurities_

24. Curves for calculating the percentage of carbon monoxide from

percentage of blood saturation ---

25. Diagram of parts of laboratory interferometer, vertical and

horizontal sections_----------

26. Laboratory apparatus for analysis of natural gas.-------

27. Apparatus for determining the solubility of natural gas in oil.

SAMPLING AND EXAMINATION OF MINE GASES AND

NATURAL GAS

By GEORGE A. BURRELL and FRANK M. SEIBERT; revised by

G. W. JONES

FOREWORD In this bulletin, the style of Bulletin 42 has been closely followed. Much of the material is reprinted on the following pages in its original form, and changes have been made only where manifestly necessary. Laboratory methods have been brought up to date. Some types of apparatus described in Bulletin 42 have now become obsolete ånd newer designs are described instead. The authors hope that this bulletin will be of as much service as was Bulletin 42.

ACKNOWLEDGMENTS Revision has necessitated the inclusion of data that have been published within the last few years. Proper credit is always given the authors of such material by references to the original articles. The reviewer especially acknowledges his use of information taken from papers prepared by R. R. Sayers, W. P. Yant, G. G. Oberfell, M. C. Teague, I. W. Robertson, F. N. Neumeister, W. C. Harpster, W. L. Parker, S. H. Katz, J. D. Davis, and A. C. Fieldner.

INTRODUCTION TO BULLETIN 42 The Bureau of Mines, as part of its designated duty of investigating the causes of mine accidents, is conducting at its experiment station in Pittsburgh, Pa., a study of mine gases. Some of the work already done in connection with this study is outlined below.

A large number of samples of mine gas have been collected under normal conditions in returns and in splits, and at other points in the ventilating current; also at the face, in the goave or gob, in unventilated places, and wherever the air was still. Samples have also been obtained under abnormal conditions, as after explosions and while mine fires were in progress, or from sealed areas behind stoppings and dams where the air had been stagnant for some time.

1 Burrell, G. A., Robertson, I. W., and Oberfell, G. G., Black damp in mines : Bull. 105, Bureau of Mines, 1916, 92 pp.

Chemical changes in the composition of mine atmospheres during mine fires have been studied, and conditions peculiar to certain mines have been investigated.

The effect of a change in atmospheric pressure on the escape of gas (methane) in coal mines has been studied. Explosives have been fired in both coal and metal mines, and samples of resulting gases have been collected to ascertain the degree to which these vitiate the air. A series of samples in mines where gasoline locomotives were being used has been examined in order to ascertain the degree to which the exhaust gases from such locomotives foul the air.3 Experiments have also been made in regard to the relative effect of carbon monoxide upon men and small animals,4 the effect of oxygen deficiency on men and animals, and the flammable limits of combustible gases found normally in mines and during and after mine fires. 6

These investigations have necessitated making numerous gas analyses, many requiring special methods and designs of apparatus. The methods described herein are largely an outgrowth of the above investigations and are now used as standard methods at the gas laboratory of the Pittsburgh station of the Bureau of Mines.

COLLECTION OF SAMPLES OF MINE GASES

SAMPLING BY THE VACUUM METHOD In nearly all mines where there is enough air movement—say, a velocity of at least 100 feet per minute-samples of atmospheres are taken by the vacuum-bulb method. Glass bulbs of about 250-c. C. capacity (2 by 6 inches in size) are made at the Pittsburgh experiment station of the Bureau of Mines. As these bulbs are made they are evacuated as completely as possible by a high-vacuum pump, and the long capillary neck is sealed with a flame during the final stage of evacuation. Then the bulbs are labeled and numbered and are ready

2 Burrell, G. A., and Seibert, F. M., Gas analysis as an aid in fighting mine fires : Tech. Paper 13, Bureau of Mines, 1912, 16 pp.

: Hood, 0. P., and Kudlich, R. H., Gasoline mine locomotives in relation to safety and health : Bull. 74, Bureau of Mines, 1915, 84 pp.

4 Burrell, G. A., Seibert, F. M., and Robertson, 1. W., Relative effects of carbon monoxide on small animals : Tech. Paper 62, Bureau of Mines, 1914, 23 pp.

5 Burrell, G. A., and Oberfell, G. G., Effects of oxygen deficiency on small animals and on men : Tech. Paper 122,, Bureau of Mines, 1915, 12 pp.

6 Burrell, G. A., and Seibert, F. M., The inflammable gases in mine air: Tech. Paper 39, Bureau of Mines, 1913, 24 pp. Burrell, G. A., and Oberfell, G. G., The limits of inflammability of mixtures of methane and air: Tech. Paper 119, Bureau of Mines, 1915, 30 pp. ; Explosibility of gases from mine fires: Tech. Paper 134, Bureau of Mines, 1916, 31 pp. ; The explosibility of acetylene : Tech. Paper 112, Bureau of Mines, 1915, 15 pp. Burrell, G. A., and Robertson, I. W., Effects of temperature and pressure on the explosibility of methane-air mixtures: Tech, Paper 121, Bureau of Mines, 1916, 14 pp. Burrell, G. A., and Gauger, A. W., Limits of complete inflammability of mixtures of mine gases and of industrial gases with air: Tech. Paper 150, Bureau of Mines, 1917, 13 pp.

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