THE COLLIERY GUARDIAN. _______________________________________________________________________________ .... May 18, 1917. 955 RUSSIAN INVESTIGATIONS ON MINE GASES. In dealing with, the question of the composition of mine gases, N. N. Chernitzyn, in his work on mine gases recently published in these columns,Ogives some interesting results, obtained in the Donetz basin, for the purpose of comparison with those extracted from the works of kindred investigators in other parts of the world. He cites the authorities on,the Donetz basin, Prof. N. S. Kurnakoff, who examined the explosive gas chemically, and Prof. A. P. Li doff, who has written on the analysis of gases, etc., and gives the following analysis by Kurnakoff :— Gas from-' CO2. CH4. . 0. . N. Makeievskaya mine ... 1’04 ... 64‘91 ... 3’60 ... 30’45 Rykovskys" mines... 0’29 ... 51’96 .. 8’09 ... 39 66 Ditto ... 0’57 ... 61’08 ... 3’81 ... 34’54 The cause of the great divergences exhibited in the reports on the constitution of mine gas must be sought in the first place in the lack of uniformity of the gases investigated, and in the second, in the relatively limited accuracy of the methods of gas analysis used. Since all the other combustible constituents of explosive gas are present in very limited quantity, their detection obviously requires methods of great accuracy. The constitution of mine gas in the coal measures of the Donetz basin is still comparatively little known ; and the practical importance of such investigation, besides its theoretical interest, led the author to under- co2. Heavy hydro- carbons. O. co.' H. ch4. c2h(5. N. N. ' excess. 1 Karl mine anthracite 0’0 0 77 0’12 0 0 0’0 98’40 0’0 0’71 0’26 2. Yasinovsky mine ;. 0’28 0’88 1 80 0’0 0’0 87’79 0’0 9'25 2’46 3. Ivan shaft blower No. 1 0 07 0’52 0’27 0’0 0’0 94’19 0’0 4’95 3’93 4. Ivan shaft blower No. 2 0’37 0’60 0’00 0’0 0 0 94’<8 0’0 4’95 4’95 5. Alexandrovskaya Gora mine 0’00 0’18 0’30 0’0 0’0 96’71 00 2 81 ’ 1’69 6. Sofia shaft 0’20 0’0 0’68 0’0 . 0’0 90’50 0’0 8’62 6 06 7. Shaft No. 6 Chulkovsky mine 0’43 / 0’0 1’69 0’0 0’0 84’20 0’0 13 68 7’31 8. Central shaft Novor. Co 0’33 0’0 0’22 0’0 0’0 95’10 0’0 4’35 3’52 9. Ivan shaft in section 0’30 1 0’0 0’0 0’0 0’0 97’7 00 2’0 2’0 take the collection and analysis of gas from different mines of the Donetz basin. The analysis of the gas was performed at first with an apparatus specially constructed for the purpose (see fig.); but later a Bona-Wheeler apparatus was used. The former apparatus included various parts of the Brokman apparatus. The measuring vessel A was connected by a two-way cock, with a row of absorption pipettes, and by a three way cock K with the outer air or with the combustion tube. The pipettes were filled in sequence with a solution of caustic potash for the absorption of carbon dioxide, with fuming sulphuric acid for the heavy hydrocarbons, and with an alkaline solution of pyrogallol for oxygen. The bulb is designed for burning combustible gases by means of a platinum spiral raised to incandescence by an electric current. To the bulb is attached a gauge for reducing the gas to atmospheric pressure, and for coriecting the effect of changes of temperature a compensating water column being also provided. At the beginning of the analysis a test vessel with gas was connected to the cock K, the gas being then drawn into the vessel. At a later stage of the analysis the pipettes charged with an ammoniacal solution of cuprous chloride for absorbing the carbon monoxide or with water for the ammonia liberated by the preceding solution were connected to the test tube by means of the same cock. The original apparatus consisted of five pipettes; but as no carbon monoxide could be detected during the investigation of the gases, the last two pipettes were removed, thus considerably reducing the adverse influence of the capillaries, the examination for the presence of CO being conducted by simply connecting the transferred pipettes to the three-way cock men- tioned above. If two ’ analyses failed to disclose the pre’sence of carbon monoxide the subsequent analyses of the same gas were effected by a simplified process, in which the hydrogen and methane were burned off immediately after the absorption of the oxygen. Before this combustion a small glass tube with powdered copper oxide was connected to the same three-way cock by means of rubber joints, its other end being joined to a Hempel burette filled with mercury. Before intro- ducing the gas mixture into the copper oxide tube, the latter and the capillaries were charged with pure nitrogen, the pressure in the tube being then reduced to atmospheric by turning the cock. For the com- bustion of the hydrogen the copper oxide tube was heated to 200-275 degrees by a Jager air bath, the temperature being recorded by a thermometer fitted to the top of the air bath. The constancy of volume before and after combustion indicated the absence < f hydrogen. After this the tube was heated to a bright redness, and the methane was burnt at the cost of the oxygen in the copper oxide. The unvarying volume in this case demonstrated the absence of ethane. The carbon dioxide produced by the combustion of the methane was absorbed in the usual- way, and the gas was repeatedly forced through the copper oxide tube during absorption to mix it with the carbon dioxide there. Finally, in order to check the complete com- bustion of the methane and the absorption of the carbon dioxide acid in the first meter, a partial vacuum was produced. The cock of one burette was slightly moved and air was sucked into the apparatus through "the copper oxide tube. Then a reading was taken, the carbon dioxide was absorbed, and the balance of the methane was burnt in the bulb, and determined by the reduction in volume after combustion and by the carbon dioxide formed. As the whole analysis lasted a considerable time, the barometrical pressure was noted at each reading. The check analysis was conducted with some modification in the final stage. The methane in this case was burnt * Colliery Guardian, April 27, 1917, p. 806. in a Dreischmidt capillary. For the combustion only one-third of the analysed gas was used, oxygen being added. In this case the quantity of methane, hydrogen and ethane was ascertained by the relation between a 50 per cent, reduction in volume and the total volume of carbon dioxide obtained. Further, in the modified method, the hydrogen was sometimes absorbed by spongy palladium, heated to the boiling point of water. Before mixing the gas with oxygen, the portion of. the gas to be burned was passed through a caustic potash tube, and the remainder was removed from the apparatus; the capillaries were flushed out with nitrogen kept in the bulb for that purpose. If the quantity of combustible gases did not exceed 5 per cent., the com- bustion was carried out directly in the bulb, and then, in addition to the reduction in volume and the quantity of carbon dioxide found, the quantity of oxygen con- sumed in the combustion was also ascertained. Before and after each analysis the apparatus was tested for leakage by reducing the internal pressure to half an atmosphere, and the capillaries were flushed out with nitrogen. The precision of the apparatus was equal to 0 05—0 010 per cent. Blower Gases. The gases were obtained from fissures in or adjacent to the coal seam, and collected in a half-litre test flask with ground cocks, or in eight-litre metal vessels. The test flasks were filled with mercury, but the gas vessel with pure water. The results of the tests are shown in the following table :— The presence of oxygen in blower gas is due to the impossibility of avoiding the admission of air in taking the samples. On this account the quantity of nitrogen in the blower, calculated on the basis of the oxygen in the gas, is given in a special column in the table. No hydrogen or carbon monoxide was found. To settle this point more definitely the following experiment was made with blower No. 5. About 400 cu. cm. of the gas were passed through fuming sulphuric acid, caustic potash and calcium chloride, and then burned in an electric furnace. The result showed 0’5229 gramme of Special Gas-testing Apparatus. carbon dioxide and 0’4448 gramme of water—indicating the presence only of 0 006 per cent, of hydrogen, if no allowance is made for the fact that this method gives, more frequently than any, a certain additional weight of water. The figures for CO and C2H6 did not.once exceed the limit of error of the apparatus, but, on the other hand, analysis revealed the presence of heavy hydrocarbons (ethylene C2H6), In view of the number of check analyses made, and the concordant results, it does not seem that, mere analytical errors were in question. As the heavy hydrocarbons were absorbed by sulphuric acid, the increase in the volume of these hydrocarbons was probably due to the action of the reagent itself. In order to eliminate the resulting inaccuracy the author always used a wet meter; but for the check tests he made the following experiment with blower No. 4: After putting gas into the meter the water-filled pipette was connected to the cock K, and, after account was taken, gas was passed through, for one minute in the first test and for two minutes in the second. This was repeated after the absorption of the carbon dioxide and heavy hydrocarbons. After contact with sulphuric acid, the gas was again passed through the caustic potash pipette to remove the acid vapours. The results of the tests were as follow :— 1st test. 2nd test. Original gas reading____ ................__ 96 93 ... 97 90 After contact of gas with water __....... 97’03 ... 98'10 „ absorption of CO2 .:...... 96’69 ... 97’64 ,, contact with water____ . ...........__ 96’78 ... 97’72 „ sulphur'c acid and caustic potash 95’13 ... 97’04 ,, pipette with water............... 96’23 ... 97’11 Calculated quantity of heavy hydro- carbons before washing the gas with water ___________________________ 0’56 .. 0’60 Calculated quantity of heavy hydro- carbons after washing the gas with water _____________.:_____...._______ 0’55 ... 0’61 The presence of heavy hydrocarbons was thus confirmed by this test. As the absorption of the heavy hydro- carbons continued for not less than 25 minutes, there might have been a certain increase in the quantity of ethylene at the cost of the methane, since partial absorption of the methane by the fuming sulphuric acid may occur during contact for more than 15 minutes, though this could not have much effect on the results. In order to obviate any doubt on this account, the author took a new sample of the blower in the Ivan shaft about six months later. According to indications, this new blower was the continuance of the old blower, which showed 0’52 per cent, of heavy hydrocarbons on analysis. The gas was collected in 8-litre gas vessels, and was burnt in the combustion tube in a current of oxygen. The products of combustion were absorbed as usual by calcium chloride and soda-lime. Of course, the gas was freed from carbon dioxide and water before being burned. The relation of the weight of carbon dioxide to the weight of the water in the three last analyses was constant (each time 8 litres of this gas were burnt). 1st analysis____________............................................. 1’214 2nd „ __________............ .......................................... 1’215 3rd „ ............... ........................ 1’214 Ratio of C02 to H2O in the products of combus- tion of pure methane...................._____________ 1’222 Thus, in all three analyses there was no sign of the presence of heavy hydrocarbons, and, on the other hand, hydrogen was indicated once more. The analysis of this sample, however, yielded only 0’17 to 0’19 per cent., of hydrocarbons. Calculated to a fraction of 0T per cent., the detection of such a quantity of gas, it can be understood, cannot be called convincing. Later, new blowers from the Sofia shaft were analysed in a Bona-Wheeler apparatus, but no heavy hydro- carbons were found. As they might, however, be present in very small quantity, a very careful examina- tion was made. Thirty to 40 litres of gas were liquefied in a retort containing liquid air (the temperature of the liquefaction of methane is —164 degs.; of ethylene, —103 degs.; and of ethane, —9’5 degs. Cent.). The liquid air has a temperature of —183 degs. to —193 degs. Cent. Then the fractional distillation of the gases was performed, and samples of the separate fractions were taken for analysis. In the last fractions, which should be the richest in gases, boiling at a higher temperature than methane, the analysis, nevertheless, revealed neither ethane nor ethylene. The constitution of the two last fractions was as follows :— Heavy C02. hydro- Methane. Ethane. Last fraction but one... 0’12 ... 0 ... 99*8 ... 0 „ „ ......... 5’65 ... 0 ... 93’7 ’... 0 The accuracy of this method may be appreciated from the carbon dioxide shown, which was quite absent in the first fraction, and in the new blower was found only in the proportion of 0’2 per cent., whilst in the last fractions the content rose to 5’65 per cent. Another proof of its accuracy was furnished by the following interesting case. On one occasion, when gas was required for safety lamp %ests, in the absence of pure water the gas vessels were filled in t e shaft from the pump, containing both water and oil. On the gases being frozen, the first fraction yielded no gases at all, being absorbed by sulphuric acid; but the last and second last fraction unexpectedly yielded 5’62 and 9’0 per cent, of gases absorbed by fuming acid. Experiments with the last two blowers, which failed to yield heavy hydrocarbons, did not, of course, prove their absence in the previous four; and, moreover, they cannot be regarded as conclusive, in view of the impossibility at present of detecting the presence of heavy hydrocarbons by any other method. The residue left after the combustion of the methane was analysed, and was conditionally taken as nitrogen. Besides this, in blowers Nos. 7 and 8 traces of sulphuretted hydrogen w’ere observed. In taking the sample, this gas was clearly distinguished by the smell, but was present in too minute quantities to be detected by other than qualitative tests. Gases Liberated by Coal at Atmospheric Pressure. Blowers are relatively rare forms of the liberation of gas from the seam. Usually, however, in the goaf the gas accumulates without its presence being manifested by any outward symptoms. The constitution of any gases liberated under such conditions may, of. Course, differ from the constitution of blower gas; and in order to investigate this point small samples of fresh coal were taken from goaves. The coal was placed in glass jars with ground stoppers and cocks, either in the shaft or on the surface—in the latter case not later than 24 hours after being hewed. At the end of each 24 hours the jars were connected to a Hempel burette, into which the gas liberated from.the coal was led until atmospheric pressure was attained. The analysis of the gases taken under these conditions gave the following result:— Coal from the Yasinovsky Mine. , Heavy CO2. hydro- O. CO. H. CH,. C2Hfi. N. carbons. 1st portion 0’04 ... 0 ... 0’66 ... 0 ... 0 ... 81’90... 0 .. 17’4 2nd „ ... 0’11 ... 0’3 ... 0’99 ... 0 ... 0 ... 92’5o... 0 ... 6’1 3rd „ ... 0’30 ... 0’2 ... 0’67 ... 0 ... 0 .. 90’96... 0 ... 7*82 4th ,, ... 0’02 ... 0’2 ... 0’47 ... 0 ... 0 ... 93’87... 0 ... 5’44 5th ,, ... 0’03. ... 0’39... 0’62. ... 0 ... 0 ... 96’02... 0 ... 2’94 Coal from the Ivan Shaft. 1st portion 0 ... 6 ... 4’03 ... 0 ... 0 ... 47’93... 0 ...48 04 2nd „ ... 0’03 ... 0 ;.. 0’48 ... 0 ... 0 ...-28’64... 0 ...70’85 3rd „ ... 0’43 ... 0’17...; 0’56 ... 0 ... 0 ... 39’60.:. 0 ...59’25 4th „ ... 0’32 ... 040..; 0’67 ... 0 ... 0 ... 57’90... 0 ...40’71 5th • „ ... 0’07 ... 0’26 .. 0’60 ... 0 ... 0 ... 68’4 0 ...30’67 The oxygen and partly the nitrogen found in the analysis are attributable to the air filling the spaces between the lumps of coal in the jars. 1 The heavy hydrocarbons were determined as in the case .of blower gas, by keeping the gas over smoking sulphuric acid for 25 minutes. In the last tests, in order to.