THE COLLIERY GUARDIAN. June 4, 1915. 1172 __________________________________________________________________________________________________________ CURRENT SCIENCE AND TECHNOLOGY. Based on these results, Prof. Simmersbach estimates that, in the present condition of coke oven technology, if blastfurnace gas is used, each kilogramme of dry coal needs about 750 to 775 calories, based on a heating value of blastfurnace gas of about 900 calories per cu. m. (101 B.Th.U. per cu. ft.). In designing, this should be taken as the lowest amount necessary. * efficiency of the absorbent. The following actual results had been recorded :— 2'1 gallons benzol recovered, loss 4'5 per cent. 2 5 „ ,, ,, ,, t 0 ,, 3'0 „ „ „ „ 8'0 „ But by producing a gas of 600 B.Th.U. per cu. ft., and allowing for the loss of 8 per cent., they still had a gas of sufficient quality to obtain the best results from the incandescent mantles with our present-day burners. The Utilisation of Coke Oven and Blastfurnace Gas. The Revue de Metallurgie contains an article by M. Gouvy dealing with possible economies in, and new methods of, utilising surplus coke-oven and blast- furnace gas. M. G-ouvy favours the opinion that waste heat ovens should be employed if steam is required, and makes a comparison between the two types of ovens _________ on a power basis as follows :— Regenerative Old By-products ovens. Steam. ovens ovens (---------------A------ and and With With gas boilers. boilers, boilers, engines. From the waste heat 1,000 kg.... 850 kg.... — ... — ,, surplus gas — ... 250 kg....675 kg. ... — ____________ Benzol from Coke Ovens. At the annual meeting of the North of England Gas Managers’ Association, Mr. W. Diamond, of Marley Hill, read a paper on “ The Recovery and Fractionation of Benzol Products from Coal Gas,” in which he quoted Total per ton ... 1,000 kg....1,100 kg. ...675 kg. ... — Corresponding power— With steam engines 125h.p...l37 5h.p...84’5h.p... — „ gas engines ... — ... — ... — ... 270 h.p. He allows 8 kiloms. of steam per effective horse- power, a surplus gas yield of 50 per cent., and a con- sumption of 2,500 calories per horse-power if the gas is used in gas engines. Blastfurnace Gas for Heating Coke Ovens. In order to increase the productivity of the coke oven, it has been proposed to use as the heating medium gas produced from coal of inferior quality. In Germany blastfurnace gas has been used for the same purpose, although there is considerably less elasticity in the supply of such gas, owing both to the necessity of localising the coking plant in the neighbourhood of the furnaces, and also to the intermittency in supply, to these disadvantages there is an offset in the low cost of blastfurnace gas. In Stahl und Eisen, Oskar Simmers- bach gives an account of some tests carried out in a Koppers oven, using blastfurnace gas. A comparison with results previously obtained when heating with coke oven gas is given :— Temperatures of the Charge. some figures showing how the content of benzol in coal gas made in coke ovens varied in different seams, and from county to county :— v Benzol , County. Seam. content.* Gallons. T Barnsley................ 3'0 ... South Yorkshire 4 Parkgate................ 2'5 (.High Hazel and Blockton 3'5 ( Black Shale Main and Derbyshire.....■< Tupton Seam ......... 2'5 (.Flockton and Parkgate ... 3'0 Shropshire ..... Durnam ...... Flint and Clod.... Busty, Hutton, and ... Brock well __.....__ * Per ton of coal carbonised. 308 2'1 2'5 Beginning of water evaporation in the centre in 100° C. Heating with coke-oven gas. Heating with blast-furnace gas. End of 3rd hour. With 12'1 per cent, water. Beginning of 3rd hour. Beginning of 9th hour. With 13'1 per cent, water. End of water evaporation. End of 13th hour. Temperatures, begs. Cent. 13th hour ..... 100 ... 570 14th „ ...... 130 ... 650 16th „ ...... 200 ... 750 20th „ __...... 430 ... 820 22nd „ ..... 720 ... 900 24 th „ ..... 950 ... 1,000 26th *...... 98o ... 1,050 28th „ ...... 1,050 ... 1,080 He said the content of benzol in coal gas increased as they went south, Shropshire and Derbyshire showing about the limit. These tests were all based upon one quality of benzol, so that they were quite comparable. The general specification was that the benzol shall, in distillation in the retort, yield 65 per cent, distilled up to 120degs. Gent.; but this might be altered to suit requirements, and s-till be called benzol. He pointed out that for the purpose of recovering benzol it was necessary to have a series of scrubbers similar to those used for absorbing ammonia from coal gas. A good quantity of wash oil or absorbing oil was required. This generally consisted of well settled coal tar creosote oil. A very suitable oil—one that had a great affinity for benzol—gave the following results, approximately, on distillation :— Degs. C. 200 220 240 260 280 300 IV r cent, distillate. Nil 20 35 65 75 - 85 Specific gravity, 1'040 at 60 degs. Fahr, containing 8 per cent, of tar acids. Toward the end the temperatures. come together, because then less heat is used for the distillation than for radiation, and the oven taking blastfurnace gas, with its average top temperature 150 degs. higher, is at a disadvantage. Calculation shows that blastfurnace gas gives 44 per cent, more products of combustion at the same temperature than coke oven gas, using the analyses of the gases in the tests,'which, with the same heating surface, will give better heat transfer. Also the composition of the products of combustion and the specific heat of the constituents show that at 1,100 degs. Cent, the heat contents of 1 cu. m. from blastfurnace gas are 497-1 calories, and. from coke oven gas 477-1 calories. This combines with the greater volume of the products of combustion to give better heat transfer from the gases to the furnace walls. Theoretical considerations are also given to show that hot blastfurnace gas and heated air mix more readily than coke oven gas and air, and also give a longer flame more uniform in heating value. This gives the possi- bility of building coke ovens still higher, without special arrangements—such as heating from the top— and also ensures better and more uniform heating of the coke oven walls. As the basis of the experiments referred to, two tests were carried out, the coking time in the' first being carried to 29 hours, another hour elapsing before the coke was pushed; in the second, the time was only 25 hours. The heat balances of the two tests are worked out as follow :— The preference for using coal tar creosote was due to the possibility of the benzol becoming more polluted with paraffin when using blastfurnace creosote. In order to recover the maximum quantity of benzol, the wash oil must be kept in as uniform condition as pos- sible ; only a very narrow range should be allowed in the specific gravity. If a range from 1'040 to 1'060 specific gravity was allowed the circulating wash oil, one would be assured of securing the best results. ’When the wash oil reached 1-060, it ought to be taken out of circulation and new oil pumped in. An experiment he made with oils of different qualities gave the follow- ing results?—Goal tar creosote, 0-22 gall.; filtered anthracene oil, 0'043 gall. The apparatus, rate of flow, etc., were uniform. Both experiments were carried out at the same time. Another factor which very greatly interfered with the quantity of benzol absorbed by the wash oil was the amount of water contained in the wash oil. It should be at once removed, or brought down to within 1 per cent. The influence of water on the absorption was shown by a test he had made :— Galls. Coal-tar creosote free from water .. 0'22 2'5 per cent, water.... .. 0'14 99 5'0 „ ,, .... .. o-14 99 99 7> „ „ .... .. 0'12 99 9 9 10-0 „ „ .... .. 0’06 Per Kilogramme of Dry Coal., Calories. Incoming. (---------*---- I. II. 1. Heat value in the gas ____ 763’6,..729'9 2. Heating the gas to9’5°(I.) and 11° (II.) 2'6... 2'9 3. Air for com- bustion at 120°........ 26'4... 22'7 Calories. Outgoing. ,--------A---- I. II. 1. In the coke... 342*8...368*7 2. In the steam 147*8... 152'I 3. In the waste gases __..... 160’0... 148*9 4. Gasifying and heating ta,r and gas ... .43'1... 47'3 5. Radiation and work of coking..... 98'9... 38'5 When the quantity of water became 10 per cent, and over, the results were irregular, but below this they seemed regular. When the gas was brought down to under 60 degs. Fahr, and the wash oil was reduced to about 32 degs. Fahr., the increase in absorption was about 20 per cent.; but to do this the cost at present-day prices of refined products was prohibitive. If the gas rose above 75 degs. Fahr, there was a considerable loss —that was supposing the oil to be at 75 degs. Fahr.—so the happy medium was the most profitable. Having described the processes of purifying and fractionating the crude benzol thus obtained, Mr. Diamond said the compositions of 90 per cent, and 50/90 per cent, benzol were approximately .:— 792'6...755*5 792'6. ..755'5 Eliminating the heat carried off by the waste gases, the percentages are as follow :— Percent. Percent. I. II. Inthecoke............... 54'22 ... 60'78 In the steam............. 23’38 ... 25’07 In the gas ................. 5'81 ... 6'76 In the tar ........................... 1’01 ... 1'04 Distillation and radiation.. 15'58 ... 6'35 90 per cent. 50-90 per cent, benzol. benzol. Pure benzene Toluene Xylene 79 ‘ 8 2 19 24 10 The composition of benzols as given by Kraemer and Spilker. used in as :— 90 p.c. colour work was 50 p.c. 0 p.c. Water 0'060 . — — Paraffin 0'100 . .. 0'25 . ... 0 50 Carbon disulphide Substances absorbing,bromine, including thiophenes and the 0'686 . .. 0'39 ... — like 1'202 . .. 1'23 . ... 0'82 Thiophene, pure 0'264 . — .— Benzene 80'922 . .. 45'37 . ... 13'54 Toluene 14'855 . .. 40'32 . ... 73'42 Xylene 2'180 . .. 12'44 . ... 11'69 Reverting to the effect on the calorific value of the gas of taking out the benzol, Mr. Diamond said the effect would vary according to the coal carbonised and the 100'00 ... 100'00 THE GERMAN AND AUSTRIAN COAL AND IRON TRADES. We give below further extracts from German periodicals that have reached us, showing the course of the coal and iron trades in Germany and Austria :— Exports of German Coal to Italy by the Gothard Railway in March. Total railway consignments, 115,456 tons (17,472 tons in March 1914), of which 43,855 tons (4,915 tons) were from the Ruhr; 16,013 tons (10,940 tons) from the Saar; 2,865 tons (120 tons) from Aachen; 3,497 tons (617. tons) from Lothringen; 48,346 tons (780 tons) from Upper Rhine harbours; and 733 tons (nil) from Rheinpfalz. In the first quarter of the year the con- signments aggregated 253,983 tons (83,159 tons), an increase of 170,824 tons. Rhine Shipping. The condition of the river has latterly been favourable for traffic, the depth at Caub, and also between Lauter- burg and Strassburg, being 10 ft., so that the largest barges could pass up from Holland as far as the last- named city. With a little lightening, it has also been possible for craft to reach Basle. This is important for the coal traffic to the Upper Rhine, which has been increasing for some time. In spite of the reduced output in the Ruhr district, the consignments of coal, coke, and brown coal briquettes to the Upper Rhine have lately been very considerable, so that, although the bulk of the oncoming cargoes pass away to con- sumers at once, it has been found possible to lay up stocks by degrees against the time when shipping will be retarded by low water. The number of craft looking for freight is smaller than it was some weeks ago, but rates remain unchanged. Shipments of coal to Holland and Belgium have also increased considerably, and freights have gone up in consequence of the scarcity of small and medium craft. German Coal Syndicate Report for April. Total coal raised, 5,751,089 tons (7,912,556 tons in April last year, or 239,629 tons (329,690 tons) per work- ing day. Calculated distribution, 4,685,841 tons (6,347,946 tons), or 195,234 tons (264,498 tons) per working day, being 66-46 per cent. (90-09 per cent.) of the participation. Total coal distribution of the syndicated collieries, 6,044,239 tons (8,069,155 tons), or 251,843 tons (336,215 tons) per working day. Deliveries, including local sales, miners’ house coal,’and supplies to pits’ own ironworks : Coal, 3,496,989 tons (5,429,961 tons), or 145,798. tons (226,248 tons) per working day; coke, 1,362,205 tons (1,424,176 tons), or 45,407 tons (47,473 tons) per working.day; briquettes, 330,363 tons (367,166 tons), or 13,765 tons (15,299 tons) per working day. As compared with March, the calculated distri- bution shows an increase of 6-38 per cent, per working day, the total distribution an increase of 2’33 per cent., the distribution for syndicate account an increase' of 3-28 per cent, per working day, the total distribution of coke an increase of 3-66 per cent., and for account of the syndicate one of 8-80 per cent, per working day, whilst the distribution of briquettes was higher by 1'86 per cent., and for syndicate account 1-78 per cent, per working day. The collieries having a sales agreement with the syndicate raised 395,556 tons (473,867 tons) of coal during the month, and had a coal distribution of 354,841 tons (436,332 tons), of which 141,524 tons (179,156 tons) were for syndicate account. Total coke distribution, 101,066 tons (142,796 tons), of which 60,988 tons (97,592 tons) were for syndicate account. Total briquette distribution, 3,214 tons, all, except 2 tons, being for account of the syndicate. In the first nine months of the war, the total coal raised amounted to 51,299,080 tons (73,704,089 tons in the same period of the previous year), being a deficit of 22,405,009 tons, or 30*40 per cent. Calculated coal distribution, 39,193,657 tons (57,164,692 tons), a deficit of 31-44 per cent. Total coal distribution of the syndicated collieries, 51,218,355 tons (72,713,405 tons), a deficit of 21,149,050 tons, or 29*56 per cent. The Iron and Iron Ore Market in Siegerland. Great activity prevails everywhere, and the situation is firm. After the repeated rises in prices there has been a period of steadiness, due to the action of the various unions and associations, which now control the prices of nearly all iron products, and without which more con- siderable advances would undoubtedly have occurred, especially in pig iron and ore. At present, attempts to secure supplies for a long period ahead are confined to the ore market, whereas both producers and consumers, of rolled products will only contract for short periods, being unable to forecast the conditions of the labour market in a few months’ time. Iron Orc.—Enquiries continue specially active for ores containing manganese. The Ironstone Union is doing its utmost to keep buyers supplied with crude and roast spathic ore and brown ironstone. The local fur- naces are at a disadvantage, owing to the policy of the large .Westphalian iron works of acquiring a predominant interest in the chief Siegerland ore mines, and taking over the bulk of the output. Up to the present the union has not made any sales for the second half of the year, and has maintained silence over the prices which