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THE

JOURNAL OF INDUSTRIAL PROGRESS.

No. XII.-DECEMBER, 1854.

ART. I.—On the uses to which Turf might be applied in Ireland. No. 3. Products of the Destructive Distillation of Peat. Part I.

THE UTILIZATION OF THE WASTE GASES FROM HIGH FURNACES CHARGED WITH PEAT.

THE gases which escape from the throat of an iron furnace have a very high temperature, perhaps as much as from 1,700° to 1,800° Fahr., and hence, very soon after the introduction of the hot blast in 1829, attempts were made to apply these hot gases to heat the blast, and thus economize a certain amount of fuel. In addition, however, to the gases being in this hot condition, it was soon observed that they were combustible, and that even after having been cooled down in heating the blast, they might be burned, and an additional source of heat obtained. Up to a recent period, however, but little advantage appears to have been taken of this important fact in Great Britain, the greatest iron-making country in the world; chiefly owing, it is to be supposed, to the abundant and consequently cheap supply of fuel, which rendered it scarcely worth a manufacturer's while to endeavour to overcome the great difficulties which beset the economization of the waste gases in the first instance.

In France, Germany, and Sweden, where fuel is very dear, it attracted, on the other hand, immediate attention. Even so early as 1836 an attempt was made at Wasseralfingen, in Germany, to puddle iron by means of the combustion of the waste gases; and in the same year a patent was likewise granted in France to a M. Sire, who made some trials at Clerval. Subsequently to these trials, the Messrs. de Dietrich, of Neiderbrunn, whose names are honourably connected with improvements in the manufacture of iron in France, made a great number of experiments upon the best method of collecting the waste gases, and of applying them to the purposes of iron puddling. Later still, further improvements were effected in the modes of burning the gases in puddling, the most important of which was the employment of heated air, which was made to

play on the hearth, and the iron thus more rapidly decarbonized. All these attempts were, however, only partially successful, in consequence of the difficulty of collecting the gases without interfering with the proper working of the furnaces, and of then regulating the proper supply of air necessary for their combustion.

In 1841, MM. Thomas and Laurens, who are among the most distinguished engineers of France, put up a puddling furnace at Treveray, which, although far from perfect, gave an immense impulse to the application of the waste gases, which are now employed on the Continent to roast ores, burn lime, raise steam for working the blowing engines, and in the refining and puddling processes. In Great Britain, too, their use is at length beginning to be appreciated, especially in Wales and in Scotland, and no doubt can exist that before long, the great improvements which have been effected in the modes of collecting the gases and in their subsequent application, joined with the increasing cost of fuel, will lead to the general adoption of closed furnaces, and the utilization of all the waste gases throughout England and Scotland.

While the attempts of which we have above spoken were being made to utilize the waste gases, the late M. Ebelman, the distinguished director of the Porcelain Works of Sevres, conceived that if the waste gases of an iron furnace could be advantageously employed as a fuel, he might directly obtain a supply of similar gases, by burning small coal, peat, or other inferior fuel in a special furnace, from which the gases might be conducted to those points where they would be required. In this way he hoped that pyritic and shaly coals, and all similar carbonaceous substances, which could never be employed directly as fuel in the manufacture of iron or glass, &c. might be utilized. This ingenious idea, which held out so many advantages to districts having in them seams of inferior coal or abundance of peat, does not seem to have immediately led to the practical results which might naturally have been anticipated. Recently, however, the case has been different, and there is at present at Ilsenburg, in the Hartz, a gas puddling works most successfully carried on, the gas for which is obtained with turf, the cones of the pine, and sometimes even the bark, dried weeds, &c. are employed.

In 1849 Mr. Rees Reece obtained a patent for an ingenious development of this idea of Ebelman. When we distil wood, peat, or coal, we obtain three classes of products, namely tar, a watery fluid, and gas. If the temperature at which the distillation is effected be low, the tar will yield, together with certain oils, a quantity of a solid fat-like substance, termed paraffine, and will be more or less solid; if the temperature, on the other hand be high, the tar will be more liquid, and will yield but little paraffine, which will be replaced by oils of analogous composition. In the aqueous liquor is found ammonia, and in the case of wood and turf, acetic acid and methylic alcohol, also called wood spirit or naphtha. The gas consists of a mixture, in varying proportions, of carburetted hydrogen, olefiant gas, and vapours of substances which would be liquid at a very low temperature. Peat, as usually obtained and air-dried, contains a large quantity of water, so that if we expose it to the process of distilla

tion, the presence of this water will keep the temperature very low until a considerable portion of the volatile products will have passed off, and hence the tar will be rich in paraffine, and consequently almost solid.

If

M. Ebelman's process for obtaining gas is a species of distillation. a quantity of peat or coal be introduced into a furnace, and the bottom be kindled and a blast of air made to act upon it, the under stratum will be consumed, and will yield a body of intensely heated gas, which in its passage upwards will coke, that is, distil, the superincumbent layers; the tar and aqueous products being volatilized and carried off. The coke thus formed will gradually sink in the furnace, and serve to replace that burned away, while fresh fuel is filled in on top, and is in its turn distilled. Now Mr. Reece proposed, by the patent alluded to, to collect the tar and aqueous products carried off along with the gas; and while the gas formed the primary and sole object of the process of M. Ebelman, it formed only the secondary object in the patent of Mr. Reece, the primary one being the tar and aqueous products.

According to the original specification (sealed the 23rd of January, 1849) the peat was to be burned in blast furnaces, in the bottom of which was to be placed a grating or set of fire bars, under which the nozzles of the tuyeres were to be inserted, by which the blast was to enter,— the pressure of the blast proposed to be employed being from 2 to 23 lbs. on the square inch. Each furnace was to be provided at top with a cover, which was to be raised whenever the furnace required to be charged, an operation which was to be performed at intervals, care being taken that the charge in the furnace did not descend so low as to go out. When the furnace was closed with its cover, the gas and other products of the distillation were to be conducted off by pipes leading from the upper part of each furnace, and dipping into water contained in a closed trough, in the manner of a hydraulic main in a gas works. A portion of the tar and aqueous products would be deposited in this box, but the greater portion would still remain in the state of vapour, and hence the gas was to be conducted through a series of pipes, forming a kind of great worm immersed in water, where they were to be deposited, and thence allowed to flow into a proper receiver, whilst the gases and non-condensible vapours, on their exit from the condensing apparatus, were to be conducted to the several flame beds where they were to be burned.

From the tar Mr. Reece proposed to prepare paraffine, which might serve as a substitute for spermaceti in the manufacture of candles, and a number of oils, and from the aqueous liquor, naphtha, sulphate of ammonia, and acetate of lime. In the separation and purification of these various products heat would naturally play a very important part, and a considerable quantity of fuel would accordingly be required, but this fuel, Mr. Reece hoped, would be supplied by the waste gases, which he proposed to employ as the sole fuel in raising steam for working the blowing cylinders for distilling his tar, and in the purification of his oils and paraffine, and in the separation of the other products.

This was the most novel part of the idea, for a factory worked upon this principle would be a kind of automaton. The peat put into the

furnace having been first distilled, so as to yield its tar and water, would descend as charcoal into the body of the furnace, where it would act as fuel to carry on the distillation of fresh peat. There it would be resolved into combustible gases and ashes, the latter being removed from time to time, while the gases would go to raise steam to work the blast, and carry on all the other operations. The furnaces would thus be the centre of action, and if these ceased to work all other operations would cease simultaneously.

To carry out this novel manufacture a company was formed under the title of the Irish Peat Company, with limited liability, under a royal charter of incorporation. The following statement from the prospectus of this Company represents the commercial results which its promoters expected to realize from the working of a factory capable of consuming 100 tons of peat in the twenty-four hours, or 36,500 in a year, and which, it further stated, could be erected and worked for the sum of £10,000:

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Cost of sending to market and other incidental charges,

2,182

£11,717

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Which would leave a nett profit of £11,908, or a little more than 100 per cent.

The idea of obtaining so enormous a profit from a manufacuture having for its raw material turf, a substance which had hitherto offered so narrow a field for speculation, notwithstanding the innumerable projects set on foot in connexion with our peat bogs, naturally excited the most lively interest, especially at a moment when the country had scarcely yet begun to emerge from the desolation caused by famine and disease. It was accordingly considered advisable to test by experiment the accuracy of the statement put forward in the prospectus of the company with regard to the amount of products which could be obtained from a given weight of turf. For this purpose a long series of experiments was instituted in the laboratory of the Museum of Irish Industry, upon a great variety of peats, from different parts of the great central bogs of Ireland. Only a certain number of these were distilled on a large scale, the density, amount of nitrogen, and composition of the ash, and the amount of charcoal and

volatile products yielded by them, were alone determined in the case of the remainder. We shall give a summary of all the results obtained in the case of the former, and leave those of the latter entirely out of consideration.

The great bogs in the centre and west of Ireland are very similar in character, and are of remarkable depth, often averaging from 20 to 36 feet. The peat of these bogs is usually of three kinds: 1, an upper stratum of soft spongy moss turf, of a pale colour, and composed almost exclusively of bog mosses; 2, a middle layer of brown peat, more or less earthy, containing many remains of roots and stems of trees and other plants, especially of heath; and 3, an under layer of black compact peat, devoid of all vegetable structure. The upper surface or flow peat varies very much in thickness, according to the nature of the bog and the part of it, being in some places only a few inches, and in others several feet. The brown turf constitutes the great mass of the bog, and gradually passes into the black, which, in the lower layer, close to the clay or gravel upon which it rests, gets intermingled with a portion of the subjacent clay or gravel, and when burned consequently leaves a large quantity of ash. None of the peats of which we are now about to speak had this character; some were very black, but should nevertheless be considered merely as the under layers of the brown turf, the kind usually employed as fuel.

The number of samples of peat subjected to distillation was six, of which the following table contains the name of the locality, the description, and other particulars.

No. of Specific

Specimen.

Gravity.

Description.

Locality from whence obtained, and character of bog.

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Light surface peat of a pale reddish brown colour, containing small roots of heath, and leaves of grasses and of bent.

Rather dense peat, of a dark reddish brown colour, structure of moss, still distinguishable, but species difficult to be determined.

1. Both specimens were obtained from Mount Lucas Bog, lying one mile south of the town of Phillipstown, in the King's County. According to Griffith's Survey, made in 1810, this Its highest bog covers 6,582 acres. point above high water of Dublin Bay, 294 feet, and lowest point 214 feet, and its average thickness 18 feet. The entire district about this town is covered with bogs averaging from 1,000 to 8,000 acres each in extent, and having an average depth of from 18 to 20 feet. Light surface peat, of a 2 and 3. From the Wood of Allen, pale yellowish brown co- which forms part of the great Timahoe lour, very open-grained and | Bog, lying to the north east of the fibrous. Principally com- Grand Canal. The specimens were

* See Parliamentary Report on the Nature and Products of the process of the Destructive Distillation of Peat, by Sir Robert Kane; and the Appendix thereto, containing the account of the experiments and processes employed, and the tables of the results, by Sir Robert Kane and William K. Sullivan.

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