22 



NATURE 



[March 2, 1916 



Chemical Aspects of the Peat Problem. 



Extensive deposits of peat exist in Great Britain, 

 France, Russia, Italy, Scandinavia, Germany, and 

 Austria. One-seventh of the total area of Ireland is' 

 covered by peat, and enormous tracts of this deposit 

 are found in Canada. 



Only two years before the outbreak of war a prac- 

 tical solution of the peat problem was claimed for 

 Germany by Dr. Carl Duisberg, of Elberfeld, who at 

 the Congress of Applied Chemistry held in 1912 at 

 New York, stated his case in the following words : — 



" The latest and most rational method of utilising 

 the peat or turf beds which are so plentiful in Germany 

 and many other countries is practised in Schweger 

 Moor near Osnabriick, according to a process dis- 

 covered by Frank and Caro. There peat gas is pro- 

 duced and utilised, and ammonia obtained as a by- 

 product, the required power being generated in a 

 3000-h.p. central electric power station. The moor- 

 land, after removal of the peat, is rendered serviceable 

 for agricultural purposes." 



The foregoing development appears to be a practical 

 realisation of the view held by man^' workers on peat 

 in this country, that the most economical use to make 

 of this combustible is to convert it into gaseous fuel 

 in suitable gas producers. 



When peat is gasified the products are combustible 

 gas, ammonia, ash, tar, and an aqueous distillate con- 

 taining certain technically important organic com- 

 pounds. The combustible gas, which is generally free 

 from sulphur, consists of carbon monoxide -and 

 hydrogen mixed with the non-combustible gases, 

 nitrogen and carbon dioxide. 



At present the only plant of this description in 

 Ireland is the gas-producer furnishing the gaseous fuel 

 for the gas engines of the factory of Messrs. H"amilton 

 Robb, Ltd., of Portadown, and although, on account 

 of the comparatively small capacity of the plant, no 

 attempt is made to recover and utilise any by-products, 

 yet, nevertheless, this installation has proved to be a 

 financial success. There can be little doubt that in a 

 scientifically controlled plant, large enough to render 

 practicable the recovery of ammonia and other by- 

 products, the economy effected would be considerably 

 greater. 



By-Products from the Peat-Gas Producer. 



Ammonia. — Peat may contain from 05 to 25 per cent, 

 of nitrogen, and by passing steam over peat heated to 

 350-550° almost the whole of the nitrogen is obtained 

 as ammonia. This improvement has been embodied in 

 the modern types of Mond plant, so that now it is 

 possible to recover the greater part of the nitrogen of 

 peat in the form of the valuable fertiliser, ammonium 

 sulphate. The importance of increasing the output of 

 ammonium sulphate from peat lies in the circumstance 

 that this salt can displace sodium nitrate as a nitro- 

 genous manure, thus rendering the nitrate available 

 for the manufacture of explosives and other chemical 

 products. 



The Power-Gas Corporation, Limited, of Stockton- 

 on-Tees, who in IQ05 first turned their attention to 

 this method of utilising peat, have obtained the follow- 

 ing extremely favourable results : — 



German Italian Engl'sh 



Fuel used peat peat peat 



per cent. per cent. per cent. 



Moisture content of fuel 40 to 60 15 57"5 



Nitrogen content of fuel ... I'D i "58 2"3 



Quantity of gas produced per cubic ft. cubic ft. cubic ft. 



ton of theoretically dry peat. 85,000 60.000 90,000 



B.T.U. Fi.T.U. H.T.U. 



per c.f. p«rc.f. per c.f. 



Heat value of gas produced ... 150 Ib6 134 



Sulphate of ammonia produced 



per ton of theoretic.-illy dry 



peat 70 ib. 1151b 2151b. 



The Simon-Carves Bye-product Coke-Oven Construc- 

 tion and Working Company, Limited, have made 

 large-scale experiments on the gasification of peat in 

 Moore gas-producers. Peat, containing 63 per cent, of 

 moisture and with a nitrogen content of 2235 per 

 cent., yielded per ton 94,850 cubic ft. of gas (ico 

 B.T.U. per cubic ft.) and ibS lb. of arnmonium sul- 

 phate. 



Peat Ash. — Peat differs from wood in yielding on 

 combustion a comparatively large proportion of mineral 

 ash (5 to 15 per cent.). The ash of peat contains the 

 oxides of aluminium, iron, and calcium existing to a 

 considerable extent in the form of carbonate, sulphate, 

 silicate, and phosphate, a very appreciable amount of 

 alkalis, with a preponderance of potash. By using 

 the peat ash as a dressing for the recovered land the 

 potash locked up in peat would be rendered available 

 for agriculture at a time when the- shortage of this 

 alkali is felt ver}' acutely. 



Peat-producer Tar. — The incomplete combustion of 

 peat in the producer leads to the formation of a certain 

 proportion of tar which is collected in the hydraulic 

 scrubbers of the plant. 



The amount of tar produced yearly in the Portadown 

 plant is about one hundred tons. Samples of this 

 waste product were examined in the chemical labora- 

 tories of the Royal College of Science for Ireland, 

 when substances of industrial importance were isolated. 

 A greatly increased output of the peat tar is, how- 

 ever, the first essential step towards commercial suc- 

 cess in this direction. Ten installations comparable 

 in size with that of Messrs. Hamilton Robb, Ltd., 

 would yield approximately an annual output of 1000 

 tons of peat-producer tar, a quantitj' which would 

 furnish a practical basis for the industrial exploitation 

 of the derivatives of this tar. 



Distillation of the moist crude producer tar effected 

 a separation of certain volatile oils from a non-volatile 

 bituminous material (crude pitch) amounting to about 

 17 per cent, of the total tar. By heating the crude 

 pitch to 122° C. and pouring off the liquid portion, 

 about 6 per cent, of a refined soft pitch could be separ- 

 ated from a solid friable carbonaceous residue. 



This pitch, either alone or mixed with the carbon- 

 aceous matter, could be used as asphalt, as a caulking 

 material, or as an insulator in electrical work. The 

 carbonaceous matter could be utilised separately as a 

 self-briquetting combustible of hig-h calorific value. 



The moist peat-producer tar yielded on distillation 

 50 per cent, of volatile oils ; the latter by further treat- 

 ment were separated into neutral oils, waxes, and 

 acidic oils. 



Acidic Oils. — Fractional distillation of the acidic oils 

 showed that these substances consisted principally of 

 complex phenolic compounds. Attention was specially 

 i directed to these substances as they seemed likely to 

 '- afford material for the manufacture of useful dis- 

 I infectants comparable in efficacy w-ith lysol, creolin, 

 I cyllin, and other coal-tar disinfectants. 

 I The well-known Rideal-Walker test for disinfectants 

 and the modified procedure devised by Martin and 

 Chick afford methods for controlling quantitatively the 

 separation of the germicidally active acidic oils from 

 peat tar, and for ascertaining the bactericidal value of 

 these acidic oils. Phenol and the cresols are segre- 

 gated in the fraction boiling below 200° C, which is 

 about seven times as toxic as phenol itself towards 

 Bacillus typhosus. The fraction of acidicpeat oil boil- 

 ing at 200-250° is seventeen times as active as phenol 

 (carbolic acid) on the same pathogenic organism. 



The most intense germicidal activity is possessed by 



the fraction of acidic peat oil boiling at 253-360°, for 



this product has a phenol (carbolic acid) coefficient of 31. 



These results show that by distillation and simple 



NO. 2418, VOL. 97] 



