404 GAS MANUFACTURE 



eight tons of coal can be dealt with at a time, and it has met with considerable success, 

 especially on the European Continent, where a number of installations have been erected. 



The first chamber setting was erected in 1901 at the Munich works by H. 



Ries and E. Schilling, who converted an old setting for inclined retorts by 

 carboalsa- building into it three chambers, each taking a charge of one ton of coal, the 



floors of the chambers being at an angle of 35 to facilitate charging and dis- 

 charging. This plant was so successful that the chambers were enlarged, and later on in 1906 

 an installation of fifteen chambers in groups of three per setting was erected. Each chamber 

 takes a charge of two and a half to three tons, and the carbonisation is continued for 24 hours. 

 A regards results, Dr. Bunte in 1907 reported that he obtained 11,342 cubic feet per ton of 

 Saar coal, having a gross calorific value of 626 B Th U per cubic foot. 



The success of the Munich plant was followed by the erection of a larger installation 

 at Hamburg. The chambers consisted of ten settings of three chambers each, the chambers 

 being 24.6 feet long by 7.4 feet high, the width varying from I foot 8 inches in the outside 

 chambers to 2 feet in the central chamber. Carbonisation takes 24 hours, and the capacity 

 of the three chambers is 17.5 tons. A still larger installation of twelve settings of three 

 chambers each was erected at Moosach, the length of the chamber being increased to 28.7 feet. 

 At many other places on the European Continent chamber ovens were erected by H. Kop- 

 pers, A. Klonne and Knoch, and the Koppers system is now to be tried at Birmingham. 

 Horizontal, vertical and inclined chambers have all been tried, and each has its advocates, but 

 the tendency seems to be to revert to the horizontal chamber with mechanical coke pusher. 

 The great advantage of chamber carbonisation is that it reduces the cost of handling 

 and labour, and it has been stated that a labour charge of gd. has been reduced to f d. ; 

 on the other hand the candle power of the gas is below the English standard, although the 

 calorific value is satisfactory, and the initial cost of erection is very high. 



Mr. Charles Carpenter, at the South Metropolitan gas works in London, carried out some 

 experiments with ordinary horizontal retorts by filling them full of coal, as had been sug- 



gested by Kunath in 1885, instead of only partially filling them, an operation 

 Full charges W j 1 j c i 1 became a possibility only with the perfecting of charging and discharging 

 retorts* machinery. He found that a considerable improvement was effected in the 



make and quality of the gas as well as in the tar. This is no doubt largely due 

 to the elimination of the large space that was left above the charge of coal in the old practice, 

 which led to the degradation of the gas and tar vapours owing to contact with the red hot 

 crown of the retort, and the fully charged horizontal is being adopted at many works not 

 yet prepared to instal verticals. 



All the various systems of carbonisation in general use fully charged horizontal retorts, 

 intermittent vertical retorts, and continuous carbonisation retorts show but little variation 

 in the amount of gas they yield per ton of coal carbonised, but if the fuel consumption be 

 taken for comparison, the continuous vertical retorts show a decided gain, the following 

 figures giving the amount of fuel consumed per 100 Ibs. of coal carbonised: 



Horizontal. Intermittent Continuous Carbonisation 



vertical. Woodall-Duckham. Glover-West. 



14 15 12. I 10.3 



The low figure obtained in the Glover- West system is accounted for by the regeneration of 

 the secondary air supply by the waste heat from the coke. 



The continuous vertical retort also has other minor advantages. In the ordinary gas- 

 works practice and with intermittent vertical installations the surrounding air is periodically 

 rendered offensive by outbursts of steam and smoke from the charging and discharging of 

 the retorts and the quenching of the coke, but in the continuous vertical there is none of this 

 annoyance; the plant works with perfect cleanliness and absence of nuisance, whilst the 

 coke, owing to being cooled before exposure to the air, requires no spraying with water. 

 The quality of the coke and tar and the yield of ammonium sulphate also are improved, so 

 that continuous carbonisation in vertical retorts offers the most advantages,. 



The great improvements in gas and residuals alike brought about by the introduction of 

 the vertical retort and the fully charged horizontal are due to the elimination of the over- 

 decomposition of the hydrocarbon gases and vapours that used to take place with the old 

 practice of only about half filling a horizontal retort with the charge of coal to be carbonised. 

 Under these conditions, as the heat began to penetrate the charge, the gas that was evolved 

 passed up into the empty space in the crown of the retort, and was there subjected to radiant 

 neat from the retort walls, which are at a temperature of upwards of 1000 C., and also to 

 contact with them, the latter being destructive to the more easily decomposed hydrocarbons, 

 breaking them up into simpler hydrocarbons, hydrogen and free carbon, the latter forming 

 deposits of retort carbon on the interior of the crown of the retort and soot, found as free car- 

 bon in the tar. As the heat penetrates the carbonising mass, the outer portion of the 

 charge becomes redhot coke, and the gas distilling from the inner core has to force its 

 escape through this, so that not only contact but catalytic action of the carbon surface adds 

 to the destruction of the hydrocarbons; as this action increases with the thickness of the red 



