NITROGEN FROM THE AIR.

Progress, Volume XIII, Issue 3, 1 November 1917, Page 63

NITROGEN FROM THE AIR.

By J. OR CHI ST ON, M.I.E.E.

b[Mr. Orchiston’s Paper on obtaining Nitrogen from the Air (a process that has been one of the main sources of supply of I nitrates for Germany since she discovered it), which was published in condensed form in the newspapers, is here published in full, with an illustration of the plant required to carry ont the scheme.] v£§yv

In 1785 Lord Cavendish and Mr. Priestley, an English chemist, discovered that by means of electrical sparks in a glass tube, nitrons vapours could be produced. In 1902 D. 11. Love,joy and Charles S. Bradley published the results of their experiments at the Niagara Falls in the production of nitrogen from

Notodden and Rjukan Falls. At that period the demands so far exceeded the production that they had orders on hand for all they could produce for twelve months ahead. It was then decided to enlist fresh capital to duplicate the factory at Rjukan. The Germans were at one time interested, but the Scandinavians would not let them have control, and

the air. They used 12 h.p. of electric energy, which cost them at the rate of 18 dollars per h.p. per annum. Although this can only be classified as a laboratory experiment they demonstrated the fact that given cheap power the fixation of atmospheric nitrogen by electricity was a feasible proposition. Shortly after Lovejoy’s and Bradley’s experiments, two Scandinavian inventors, Professor Birkeland and Doctor Eyde, of Norway, developed a practical scheme, and by 1911 they had some two hundred thousand horse power harnessed at the

as the Norwegian Parliament passed laws having that effect, they withdrew. At the same time Lord Rcvelstoke was asked by French banks to appoint an expert to report on the process. The late Dr. S. P. Thompson, an electrical engineer, was chosen, and his favourable opinion caused the French to assist. They have had every reason to be satisfied with the investment, and their co-operation is fortunate for the Allies. The duplication of the Rjukan plant which was commenced before the war, was completed last year.

The power developed on the Rjukan River now exceeds 300.000 h.p., wholly devoted to the fixation of atmospheric nitrogen by means of the direct arc process.

Before the war there were a few factories in Austria, Germany, France and Italy, where water power could he obtained at moderate cost. None of these, however, compared in size or output to that of the Norwegian factories. This is, no doubt, to he accounted for by the fact that these countries do not possess any large water powers which could he so cheaply harnessed as those of Norway.

Immediately prior to the war, Germany no doubt recognising that in spite of her submarines and Zeppelins, she might be cut off from the Chili nitrates, set about the establishment of immense works at Biteeld, near Berlin, for the fixation of atmospheric nitrogen, using a poor 1 class of lignite of low calorific value for generating the necessary power to drive the electric dynamos. Some hundreds of thousands of horsepower are now being generated, and according to the accounts received in the United States before relations were broken off, no less than 600,000 tons of cyan amide, 500,000 tons of nitrate, by means of the Haber process, and 400,000 tons from the gas retorts, a total of 1,500,000 tons of nitrogen compounds, were then being produced in Germany.

It is therefore very evident that but for the electric fixation of nitrogen, Germany would have been unable to find sufficient nitrogen to meet her enormous demand for the manufacture of explosives, and hence the Avar would, in all probability, have been over before now.

Prior to the war Germany was the largest importer of Chili nitrates, taking no less than 900,000 tons per annum. The United States was next, with 600,000 tons, while Great Britain only imported about one sixth the ouantity that Germany did. The total exports of Chili nitrate was then about 2,000,000 tons per annum, now it exceeds 3,000.000, in spite of the fact that the central powers have ceased importations. Before the Avar it was estimated that two-thirds of the Chili exports were utilised as fertilizers, and one-third for explosives and other chemical works. Since the Avar these conditions have been reversed. I may here mention that Chili levies an export tax of some £2 10s. per ton, and must therefore be deriving a revenue at the present time of some seven or eight millions from this source alone.

Germany only produced some 20,000 tons of nitrate from the air in 1913, which otcav to 100.000 tons during 1914, the first year of the Avar. After •the battle of the Marne she realised that her reserves of nitrogen might not be enual to her needs, in spite of a windfall of 250,000 tons found in Antwerp. Every endeavour Avas then made to expedite the completion of fresh factories with the result that she is now turning out one million one hundred thousand tons of atmospheric nitrates per annum.

The poAver produced at the Biterfeld Avorks costs £6 ss. 74d. per h.p. per annum. which is a loav figure for electric poAver produced by steam. I

Notodden per h.p. year. It will therefore be noted that the cheap steam power developed in Germany docs not compare favourably with the Norwegian water power schemes.

It has often been argued by engineers and financiers, especially in the United States and in Great Britain, that water powers have little advantage over first class steam plants, where coal can be obtained at moderate cost. This holds good where expensive races, dams, and pipe lines have to he provided, which, in addition to a high capital outlay, may involve heavy maintenance charges for the upkeep of the races, renewal of pipes, etc. In most cases first class water powers are located in mountainous regions far removed from close settlement. It is true that the modern development in the electric transmission of power has enabled many water powers to be utilised, which were otherwise of no practicable value owing to their inaccessible locations. Such electric transmission has its limits, however, largely from an £. s. d. point of view. The greater the distance the more expensive such transmission becomes, not only proportionately according to the added length of the transmission line, but the greater the distance the greater the electrical difficulties.

Reverting to the relative costs of the Norwegian and German poAver plants, these two systems are probably the cheapest of their kind, and among the largest power stations in the world. We have therefore a clear outline of the relative costs of both Avatei* and steam power under the most favourable conditions obtainable in each case. It Avill be observed that the poAver produced by the German steam plant at Biterfeld is 0A r er fifteen times more costly than that of the Norwegian water power at Rjukan. Hitherto the two principal methods of filing atmospheric nitrogen have been Ist, that adopted by the Norwegians, called the direct arc process for the production of a dilute nitric acid, Avhich I Avill explain shortly, and the other the manufacture of cyanamide, which process was accidentally discovered by Professor Adolph Frank and Dr. N. Caro, two Germans, Avbilc endeavouring to produce a cheap form of cyanide so largely used in mining. Briefly, cyanamide consists of ground calcium carbide impregnated with pure nitrogen gas obtained by liquifying the air under a pressure of some two hundred atmospheres. The process involves a considerable amount of labour, in addition to the cost of coke and lime for the manufacture of the calcium carbide. The finished product contains about 18 per cent, of nitrogen.

Under this system the amount of nitrogen fixed is four times as much for any giA r en power as compared to the direct arc process mostly in vogue in Norway. Hence the German preference for the cyanamide process, seeing that with them poAver is costly as compared to Norway, while labour in Germany is cheap.

It, rnav bo said of the direct arc process that it is a glutton for power, and unless the power can he obtained in large cmantitv and at low cost such method ,would not he a navahle proposition. M The principal advantage of the direct arc process ' is its great economy of labour as compared to the

The cost of the hydro-electric power in Norway j|j ranges from 5/- at Rmhan No. I to 24/7 at

gross value of the output. As far as 1 can at present judge, the value of the product should exceed one thousand pounds per annum for each man employed at the works.

It is a recognised fact that New Zealand cannot successfully compete in the world’s markets in the supply of goods which depend upon labour as the chief item in their production. Only those products which emanate from the natural resources of the country figure largely in our exports, such as wool, frozen meat, butter, cheese, gold, flax, kauri gum and timber. Although at one time the Dominion was a large exporter of grain, she is now an importer, largely due to labour conditions, as although the gross return is much less it is found to be safer to devote the land to raising sheep for their wool and mutton. Continuous cropping will, of course, also exhaust the stored up nitrogen in the soil.

The point .1 wish to emphasise is that in the manufacture of calcium nitrate by the direct arc process, the amount of labour involved in comparison to the value of the output is less than that pertaining to any of our exports excepting that of wool, and it may even run wool for first place.

The whole question therefore hinges on whether we can harness water power in sufficiently large units, and at bedrock cost, for both capital outlay and annual upkeep.

I may set your minds at rest in so far as the North Island is concerned by stating there is no water power in this Island of sufficient magnitude, combined with cheapness in developing and facility for transport of the manufactured article, which would be of value for the purpose. The only water powers which comply with all requirements arc those located on the West Coast of Otago, and in so far as the facilities for cheap installation and convenience to deep water harbours arc concerned they are unique, and I doubt if they can be surpassed in any other part of the world.

The energy going to waste in the West of Otago approximates two million horse power. If the outlet of Lake Tc Anau was diverted to George Sound by means of a five mile tunnel, no less than three quarters of a million horse-power could be obtained from this source alone, (a conservative estimate given by the late Mr. Hay, Chief Engineer of the Public Works Department). The initial capital per h.p. developed would be low, and in all probability the annual charges would not exceed the Norwegian record with the added advantage that the To Anau power would be delivered alongside a deep water harbour; whereas the Norwegian power is 86 miles inland, involving the transport of goods by two sections of railway line separated by ferry steamers and finally conveyed by small river steamers to the Port of Skien.

I may here mention that the hydro-chub development at Niagara has cost about twenty pounds for each horse power installed, whereas the Te Anau power would probably be nearer five pounds. The power sold at Niagara during the vear 1909 realised £3 12s. sd. per h.p. for that utilised in chemical works such as the manufacture of calcium caibide, carborundum, etc. This figure is too costly

for the production of atmospheric nitrogen by means of the direct arc process. To better illustrate this, approximately one and a half horse power is required night and day continuously for a whole year to produce a ton of calcium nitrate. The Niagara charges for the power alone would therefore amount lo about £5 Ss. 8d. — figure in excess of the whole estimated cost of producing a ton of calcium nitrate at the Bowen Falls, Milford Sound. On the Canadian side of the Falls, however, sixty-four thousand tons of cyanamidc were turned out last year.

Perhaps I should here mention the fact that a syndicate was formed in Dunedin some months ago for the purpose of prosecuting the manufacture of atmospheric nitrogen and other electro-chemical productions. Application was made to the Government ror the power contained in the Bowen River, Milford Sound, but so far consent has been withheld. The Bowen can be cheaply harnessed by means of a comparatively short incline tunnel, and would produce from 15,000 to 30,000 horse power. It is conveniently situated alongside deep-water, and has all the elements necessary for the establishment of a successful factory on a moderate scale There arc also a number of other possible powers, ranging from ten to twenty thousand horse power ■within five to fifteen miles, which could all be economically conveyed to the factory by electric transmission if required. The Bowen alone has sufficient capacity to produce one hundred thousand pounds worth of products per annum. It is therefore obvious that it would be in the best interests of the Dominion to encourage such an industry instead of allowing the water to run aimlessly to waste as hitherto. As the Bowen only represents from one to one and a half per cent, of the total energy available in the "West of Otago it will be seen that there are vast possibilities in this region. It is only a matter of time when it will all be utilised producing many millions of pounds worth of useful products annually As an indication of what can be done, the output of the two Norwegian factories at Notodden and Rjukan in 1911 (the year during which they held orders for twelve months ahead) was 90,000 tons of calcium nitrates, 12,000 tons of sodium nitrates, and 4,000 tons of ammonium, nitrate. The calcium nitrate was being sold c.i.f. English ports at £7 15s. per ton, and the ammonium nitrate about twenty pounds. Allowing two pounds ten for transport charges across the lakes, rivers, and two separate lines of rail in addition to the ocean freight, this left only £5 10s. and £l7 15s. per* ton respectively,representing a net total of some six hundred and thirty thousand pounds at the factories. This provided a good dividend, and induced them to find fresh capital for duplicating their principal factory as already indicated. At the present prices for calcium carbide in New Zealand the Bowen power would easily pay a hundred per cent, dividend, and carry forward a substantial balance, but of course things are altogether abnormal just now, nevertheless that would be a very profitable side line under any conditions, seeing that the cost of the power would be only one sixth of the Niagara power, where so much calcium carbide is manufactured.

Although nitrogen is one of the most prevalent elements terming over seventy-eight per cent, of the air we breath, the remainder being oxygen, it is very elusive, and therefore difficult to capture and imprison in a marketable form. Foods may vary, and so do explosives, but when analysed there is ever present one chemical element in both, and that is nitrogen. It is true there are other constituents, possibly in greater proportion, so why single out nitrogen? Because in nature’s workshop and in man’s munition factory nitrogen is the scarcest of the indispensable materials. The others arc just as essential, but they can be obtained more easily. The supply of nitrogen is usually the first to give out, and when that happens the production comes to a standstill, either in the soil or the factory. Experience has shown that land holding three-tenths of one per cent, of nitrogen will prove very fruitful, other things being equal. It may produce from thirty to forty bushels of wheat to the acre. Soil containing two-tenths of one per cent. Avill probably be good for about twenty-five bushels per acre. If one-tenth of one per cent, it may produce fifteen bushels, but if this essential plant food be as low as one-twentieth of one per cent, the ground will be too poor to produce a profitable crop. In so far as the North Island is concerned there is not so much need for this fertilizer as in agricultural countries. As a rule virgin lands contain a fair percentage of this element. ■

In the early eighties a yield of one hundred and thirty bushels of potatoes per acre was considered a prime crop in Germany, but by 1914 the application of Chili nitrates had made it possible to count upon an output of two hundred and ten bushels per acre. Because the same course was not followed by the farmers in Russia, Austro-Hungary, France and Italy with similar, if not better soil, they have not improved upon their crops of thirty or forty years ago. On the other hand Great Britain, Belgium, and Holland, profiting by Germany’s example, were able to increase their production from fifty to one hundred per cent.

Experience has shown that • every pound of nitrogen rightly applied to the soil increases the yield of wheat, rye, barley or oats, by about twenty pounds of grain and forty lbs. of straw. In the case of potatoes one pound of nitrogen will better the yield of about eighty-five pounds. Hitherto nitrogen fertilisers have not been much in demand in New Zealand. This is accounted for by the fact that virgin soils arc not so deficient in this element as ground which has had a number of crops taken off it. Another, and a very good one, is the fact that Chili nitrates have been too costly as compared to phosphatic manure. It is estimated that calcium nitrate can be produced at the Bowen and sold to the farmers within the Dominion at about one half the price previously charged for Chili sodium nitrate. It should not be overlooked that when nitrate of soda, the natural product of Chili gives up its nitrogen to plants sodium is left behind, and may be deleterious to the soil. On the other hand electrically produced fertilisers containing calcium, leave only lime in the soil, which is usually advantageous.

Before closing this paper it should be mentioned that Prof. John E. Bucher, of Brown University, New York, has brought out a patent for the fixation of atmospheric nitrogen without the aid of electricity. It seems to be a modification of the Haber process largely used in Germany. The substance of his discovery is that nitrogen will combine with an alkali and carbon in the presence of iron as a catalyst producing the cyanide. Reduced to concrete terms this means that he mixes soda ash and powdered iron with powdered coke; upon heating this mixture in an ordinary furnace and running air over it, the result is cyanide of soda, leaving the iron uncombined. It is obvious that soda ash, powdered iron and coke cannot be obtained for nothing, and that coal must be consumed in heating the furnace. 1 am therefore inclined to think that the Norwegians, with their cheap power, will not be greatly alarmed, nor will the promoters of the Bowen Fails scheme. The chief advantage of this discovery is that a factory can be quickly installed and may be producing nitrogen before the surveys of a large hydroelectric scheme are completed. There is an enormous demand for nitrogen in the United States at present for explosives, as well as for fertilisers, and it appears that the Government are devoting four million dollars for the fixation of atmospheric nitrogen, possibly adopting Prof. Bucher’s scheme. A twenty million dollar vote was passed some time ago for the establishment of a hydro-electric factory for nitrogen fixation, but from the latest accounts the committee were still considering the question of a site. A great deal of preliminary survey work is involved before the best selection can be fixed upon.