INDUSTRIAL AND EdVGINEERISG CHEMISTRY
July, 1930
economic basis the use of coal in cities cannot be defended. It involves the loading, transporting, unloading, delivering, and firing of the fuel, the disposal of ash, the loss of valuable oil constituents that can be educed by carbonization, and the adding of tremendous amounts to the cleaning bills of cities. I n addition. it is a detriment to the health and happiness of urban population. Extension of the use of natural and petroleum gases will partially solve the fuel problem, but the full solution requires the cobperation of the coal industry. In the interest of health and of economy alike a change in method of using coal is demanded. Coal should be converted into gas and gasoline in plants at the pit mouth. By carbonization proc-
795
esses coal can be converted into gas, coke, gasoline, and tar. The tar can be converted by the cracking process into inore gas, gasoline, and coke; and the coke from both carbonization and cracking can itself be converted into water gas or producer gas. The two products, gas and gasoline, could be pipe-lined to consumers, instead of shipping coal. The practicability of the piping of both gas and gasoline has been proven in the t-nited States. The adoption of this plan would be sound furl progress and a great boon to the nation. Literature Cited (1) Proc. Pactfic Coasf Gas .Isrocti , 16, 724 (1924)
Development of the Synthetic Ammonia Industry in the United States‘ Jasper E. Crane2 E. I. DU
P O N T DI: &-EMOURS
&
VERY chemical manufacturer knows what synthetic ammonia is as a new industry, and as part of the whole fixed-nitrogen industry. In every discussion of the fixed-nitrogen problem it seems to be the invariable practice to refer to two things, Crookes’ prophecy in 1900 and Muscle Shoals. May I depart from this practice and discuss neither of these? For far more words have been uttered on these subjects than they deserve. The processes of making ammonia synthetically are well known. The preparation of ammonia is very simple on paper
C O M P A N Y , ~ ‘ I L M I N G T O N . DEI.
gas. There are also supplies of by-product hydrogen from cell operations and chemical processes, but these supplies are not large enough to have any material bearing on the economics of the annnonia industry, and are too small in amount in any one place to make more than a few tons of ammonia per day and thus with the high operating cost incident to small-scale production of ammonia. For economical large-scale production of synthetic ainmonia, therefore, the first requisite is abundant supplies of the cheapest possible fuel for making water gas. Purification of the hydrogen before the synthesis step is essential, and is accomplished b? rather complicated processes S. 3H2 = 2SH3 which should be automatically controlled. but the technical problems in the preparation of pure hydroThe synthesis of the pure hydrogen-nitrogen mixture into gen and in carrying out the synthesis step under pressures ammonia is carried out at high pressures, and therefore rewhich have only recently been looked on as industrially quires heavy and costly apparatus. The consumption of feasible are so great that the synthesis of ammonia is con- power, though much lower than in other methods of fixing sidered to be the greatest triumph of chemical engineering nitrogen, is nevertheless a large element in the cost, and therethat har thus far been accomplished. fore another essential for economical manufacture is low cost power. Requirements of the Industry The disposal of the product must next be considered. It may be shipped as aqua ammonia or, more economically, as Sitrogen is readily supplied to the synthesis, either a t a small but definite cost by fractionation of liquid air or, anhydrous ammonia in specially constructed tank cars, but more cheaply, along with the preparation of hydrogen from if converted into fertilizer ingredients supplies of other raw water gas by regulating the amount of air supply so as to materials must be economically available to the producing plant. Freights are a big element in the final cost of the add the required amount of nitrogen to the hydrogen. The big raw-material problem in the synthesis of ammonia fertilizer delivered to the farmer and must be kept down to a is the manufacture of hydrogen. This may be obtained by minimum all along the line. The raw materials for the the electrolysis of water or by separation from (coke-oven manufacture of fertilizer ingredients must be assembled ecoor water gas. Electrolytic hydrogen is, on account of the nomically and delivered with the lowest possible transportalarge consumption of power, too expensive to be considered tion charges to the fertilizer manufacturer, so the location except in isolated cases. The separation of hydrogen from of the ammonia plant is an important factor in cheap fercoke-oven gas, though widely practiced in Europe, is also tilizer. Expert technical supervision and extensive experimental expensive and should not be looked on as an economic source of hydrogen in this country. Thus the Du Pont Ammonia work are necessary. The industry is moving so fast that the Corporation, though building coke ovens on the factory prern- manufacturer depending on past practices will before long ises a t Belle, W. Va., will burn the coke-oven gas under be passed by his competitors. An outstanding feature of the industry is the high cost of boilers instead of extracting the hydrogen from it. The economic source of hydrogen and that used in the large plants the complete plant from coke to ammonia, nearly two years’ of Germany, England, and the United States is coke water sales being required to turn over the plant investment. Amortization, therefore, is a very large item in the cost of 1 Received June 11, 1930. Presented before the annual meeting of production. For all these reasons the overhead expenses the Manufacturing Chemists’ Association of the United Statcs, Absecon, in producing ammonia are relatively high, and plants with N. J., June 5, 1930. large output are required to bring down these overhead 2 Vice president, E. I. du Pont de h’emours & Company.
E
+
I N D U S T R I A L A N D ENGINEERING CHEMISTRY
796 I
1
Figure 1-Production
of Fixed Nitrogen i n t h e United States (Short tons of nitrogen)
Vol. 22, x o . 7
is constructing a synthetic ammonia works in the vicinity of San Francisco. , Figure 1 tells the story of the expansion of this industry to date, but not the whole story, for it is estimated that this year the production of synthetic ammonia will amount to 148,000 tons of nitrogen. Moreover, it is believed that plant expansions that are now under way will bring the country's capacity for synthetic ammonia production in 1931 to the large total of 290,000 tons of nitrogen, almost 1000 tons S H a per day. Last year the United States was ninth among the nations of the world in synthetic nitrogen fixation in all forms-behind Germany, Great Britain, France, Italy, Poland, Japan, Canada, and Norway. x e x t year we will be a good second. By next year, when this enlarged plant capacity is realized, it is estimated that the total American investment in synthetic ammonia plants, without taking into account plants for converting ammonia into oth'er products, will aggregate $70,000,000. I t will thus be seen that a great industry has been developed in this country within the past few years. How nitrogen is consumed in this country is quickly seen by looking at Figure 2. It will be noted that the total consumption of inorganic nitrogen in 1928was 415,000 tons. The preliminary figures for 1929 show some increases over the preceding year-namely, in fertilizers, 325,000 tons; explosives, 21,000; chemicals and acids, 63,000; miscellaneous, 25,000; refrigeration, 15,000; total consumption, 449,000 tons. The gain in consumption of nitrogen in this country has been relatively rapid during recent years, but it appears likely that it has now reached a total which will increase
expenses and also in this country, with our high wages, the labor cost per unit of ammonia produced. Unfortunately this is often ignored and too many people seem to consider only the elements of raw materials, labor, and power in calculating the cost of synthetic ammonia. Particularly in Europe, many plants have been built with too small output of ammonia and improperly located to be economic producers; many seem destined to fall by the wayside. It seems timely to utter a warning against this wasteful procedure. Some of the requirements, then, for success in this industry, and by that I mean ammonia production a t rock-bottom costs, are large capital expenditures, a plant producing several hundred tons of ammonia per day, cheap fuel, cheap power, availability of fertilizer raw materials,. proper location with regard to consuming markets, and a high order of technical efficiency. Summary of American Developments
What have been the accomplishments of the American industry to date, and how far is it meeting the above requirements? The synthetic ammonia industry was founded, very ably founded, in Germany almost ten years before a start was made in this country. About 1921 the first American plant was constructed, and with great ability and broad vision the Atmospheric Nitrogen Corporation has expanded its production a t Syracuse and a t Hopewell to its present large volume. I n 1926 production a t Belle, W. Va., began and has latterly been notably expanded. Meanwhile several plants have been installed for the manufacture of ammonia from by-product hydrogen-namely, the Mathieson Alkali Works and the Roessler & Hasslacher a t Kiagara Falls, N. Y., the Midland Ammonia Company a t Midland, Mich., and the Great Western Electrochemical Company a t Pittsburgh, Calif. There is also the small plant of the Pacific Nitrogen Corporation a t Seattle making ammonia from electrolytic hydrogen. It is further understood that the Shell Chemical Company
Figure 2-Disposition
of Chemical Nitrogen i n t h e United States (Short tons of nitrogen)
much more slowly-with the growth of the country, with the gradually increasing use of nitrogen in agriculture, and with the introduction of new uses for ammonia. This increasing demand has been in the past supplied by increased imports of nitrogen, but these are now diminishing. The production of by-product ammonia has also steadily increased with the growth of the coke industry and the installation of by-produ c t ovens, so that now the coke ovens and gas works of the country have attained a production of over 180,000 tons of
July, 1930
INDUSTRIrlL AND ENGINEERING CHEMISTRY
nitrogen per year. America’s production of by-product ammonia, double that of any other country in the world, is a very important development. It will be seen from these figures that the addition of the increased production of synthetic ammonia to the production of by-product ammonia is rapidly making this country self-supporting in nitrogen.
IORDELIVERED
797
have been developed facilitating the synthesis of ammonia. The use of automatic controls has been extended and the amount of labor per unit of product has been reduced. The transportation of ammonia has been cheapened and made more efficient by the introduction in this country of heavy steel tank cars of 25 tons NH3capacity; two hundred and fifty of these cars are in service efficiently handling ammonia to users all over the United States. An American process of making nitric acid by oxidation of ammonia has proved to be of lower installation cost and more efficient in operation than the processes in use in Europe, and has really revolutionized the nitric acid industry of this country; further, the use of this process has penetrated Europe, and nitric acid manufacturers in several European countries have been licensed to use this process and have put it into operation. The manufacture of nitrate of soda from synthetic ammonia, which Europe said could not be done economically, is being carried on in this country on a huge scale; it is a beautiful product of high purity and excellent form. The addition of ammonia to superphosphate, neutralizing its acidity and adding nitrogen in this most economical way, has taken holdvery rapidly, and is being practiced by all the large fertilizer manufacturers. This treatment of superphosphate and the developments that are being evolved are proving of great importance to the fertilizer industry.
Figure 3-F’rices of Ammonia as “B” Liquor, Anhydrous Ammonia i n Tank Care, a n d Anhydrous Ammonia i n Cylinders
Xow as to prices-the situation may be briefly summarized. Cheap nitrogen is now a fact. I n Figure 3 “B” liquor is by-product ammonia in aqueous solution of intermediate quality; anhydrous ammonia in tank cars is normally the synthetic product. They now sell for the same price, the difference between the 1930 figures on the chart being the freight from producer’s plant to the consumer. The chart strikingly shows the great decline in ammonia prices that has been accomplished. Furthermore, if we go back to pre-war prices we will see that fertilizer nitrogen, depending on its form, is selling for two-thirds to nine-tenths of its 1913 prices. That is remarkably cheap. If anyone was accustomed to paying $50 for a suit of clothes before the war and could today buy as good a suit for $33 to $45, he would consider himself very fortunate. That is what has happened in the nitrogen industry. Indeed, the chemical manufacturer is doing better than that, as reference to the chart will show; he may buy his pre-war $50 suit for $25. That is, he is paging 6 cents per pound for ammonia delivered to the works instead of 12 cents per pound only seven years ago. And in cylinder ammonia we not only give him his suit a t half price, but we throw in as well a pair of shoes and a new hat. Kow this is a fact of considerable significance. Much has been said and written about cheap fertilizer nitrogen for the farmer, and cheap nitrogen is available for him today. Does the chemical manufacturer, however, realize, what is also the fact, that cheap ammonia is now available to the chemical industry? It is today the cheapest alkali except lime, cheaper even than caustic soda which sells a t 2.9 to 3.8 cents per pound, while ammonia a t 6 cents per pound is equivalent to 2.5 cents per pound of caustic soda. This young American synthetic ammonia industry, therefore, has already achievements to its credit of which it may be proud. The processes of producing and purifying hydrogen have been improved and simplified. Superior catalysts
-1
ETUANOL PRODUCTION
IH GALL015
IOO%ALCOUOL
B
3s Y
0
2 h
YEAR Production Methanol a n d Ethanol, i n U. S . Gallons Prior to 1927 all refined methanol was derived from wood distillation. The curve beyond that date represents refined methanol both from synthesis and wood distillation, the part produced by synthetic methanor being represented by the lower curve. Figure 4-Annual
These are important achievements accomplished in the face of difficult obstac!es. In every nation except our own the various private nitrogen enterprises were aided by government subsidies, assistance financial or otherwise, or protection. Private enterprise in this country had done the job alone. We have to rely on our efficiency in manufacture and the low prices a t which we sell our product to prevent this market from being flooded with foreign nitrogen. The expansion of ammonia synthesis abroad has now reached the state of overproduction, and producing companies operating,
INDUSTRIAL AND ENGINEERING CHEMISTRY
798
on a schedule of greatly curtailed output are keenly desirous of shipping excess production into this country. So the American industry has to stand, and is standing, on its own feet by virtue of its own initiative and accomplishment. Utilization of Ammonia
It is the opinion of those who are in the best position to speak that the use of fertilizer nitrogen, of which ammonia is one of the sources of supply, is too small in this country in the aggregate, and relatively too small as compared with other fertilizers. Despite the recent increase in nitrogen $1.30
~
1
I
Yol. 22,
KO.7
down epidemics. Unfortunately, however, to insure proper bactericidal action an excess of chlorine is usually added and the water thus treated has a noticeable and rather unpleasant taste. If ammonia is added to the chlorine to form chloramine, the amount of chlorine necessary is reduced to about 40 per cent of the usual standard and the bactericidal action is increased and made more thorough. Chloramine-treated water has no unpleasant taste. Another interesting new use for ammonia is as a source of hydrogen or nitrogen. Simple equipment has been designed for cracking ammonia, by which is meant the passage of ammonia gas over an electrically heated catalyst, which reverts it to 75 per cent hydrogen and 25 per cent nitrogen. This is a convenient and economical way of securing supplies of hydrogen, one cylinder of ammonia being the equivalent of seventeen cylinders of hydrogen. At present prices the cost of cracked ammonia to the user is just half that of hydrogen in cylinders. In any processes where hydrogen is being used, it will undoubtedly pay well to substitute cracked ammonia. If nitrogen is needed as an inert gas in certain chemical operations, a simple and economical way of securing the supply is by the purchase of ammonia in cylinders, cracking the ammonia, and burning out the hydrogen by admixture with air. As air already contains 80 per cent nitrogen, one cylinder of ammonia treated in this way will give the equivalent of thirty-six cylinders of compressed nitrogen at oneninth the cost. Cracked ammonia is suited for use in all the standard kinds of welding, both torch and shielded arc. Particularly in welding non-ferrous metals where oxidation and carbonization must be prevented, the use of this hydrogen-nitrogen mixture is ideal. A special use is indicated in the atomic hydrogen welding process introduced by the General Electric Company, which has found cracked ammonia to cost less than 70 per cent as much as electrolytic hydrogen prepared wholesale for atomic welding work.
Figure 5-Comparative Prices of Methanol and Ethanol per U. S. Gallon
consumption, mixed fertilizers used throughout the country in 1929 contained plant foods in the proportions 4 parts of nitrogen, 10 of P,Os, and slightly under 5 parts of K20. I t is confidently believed that a more efficient ratio, more profitable to the farmer, would be 5 : 10 : 5 , or approximately 25 per cent more nitrogen than is now used in commercial fertilizer. The trend is undoubtedly in that direction. Further, the increased use of fertilizers, particularly high-nitrogen fertilizers, will render great benefits to agriculture. Farming, our basic industry, is among our most unhealthy industries. The prosperity of the American farmer lags behind that of the industrial worker. The use of machinery on the farms in this country has progressed wonderfully, enabling them to produce on the average three times as much foodstuffs per man per day as do the European farmers. But on the contrary the amount of crop per acre in the different European countries is twice as great, and in some countries even four times as great as in ours. The increased use of fertilizer, particularly of nitrogen, enabling our farmers to raise larger crops on the same amount of land or the same crop on a much smaller acreage will save labor, reduce costs, and lend a great contribution to the economic health of the farmer. A new use for ammonia which is just beginning is in treating water in combination with chlorine. We all know how extensively chlorine is used for water purification and what wonderful effects it has had in reducing disease and cutting
I
'
UISCELLANEOUS
'
WOOD ALCOHOL FOR
DLNITURING PURPOSCS
Methanol Figure 6-Methanol
j '
Ethanol a n d Ethanol Percentage Distribution of Consumption
Ammonia is now used for nitriding steel, which is equivalent to case-hardening. I n addition to hardening the steel, the ammonia treatment makes it rustless. This use is only in its infancy, but it looks very promising. Other new uses for synthetic ammonia are by the oil companies for injection into pipe lines to reduce corrosion, and in oil refineries for neutralizing traces of acid which remain in the oil after the acid treatment. The cheapness of ammonia as an alkali has already been mentioned. It has other advantages. It is a milder alkali than caustic soda and it can be easily recovered by distillation from many operations, thus cutting down operating costs still further. At present prices its use is very interesting in certain organic syntheses. Summarizing the above briefly, this new raw material,
July, 1930
I S D C S T R I A L S S D E S G I S B E R I S G CHEMISTRY
synthetic ammonia, has displaced nitrate of soda in the nianufacture of nitric acid and in sulfuric acid chamber plants. It has cheapened and improved the manufacture of nitrogenous fertilizers and seems destined to lend a weighty contribution to the improvement of American agriculture. It is finding many interesting new web in water piirification, the preparation of hydrogen and of nitrogen, for welding, for nitriding steel, for neutralizing acids, and as a raw material in organic syntheses. Synthetic Organic Compounds
The products allied to synthetic ammonia-That is to say, the other Compounds that are being manufactured by high-pressure synthesis-may also be of interest. The first of these is methanol, the synthetic production of which is rightly considered another triumph of the high-pressure industry. I t was first patented by General Patart in France in 1921. The production was first developed ctn a large scale by the I.G. in Germany in 1924. I n this country there are understood to be three manufacturers of synthetic methanol-the Commercial Solvents Company, the Carbide and Carbon Chemicals Corporation, and the Du Pont Ammonia Corporation. A particular advance is the American process of producing methanol as a by-product in the synthesis of ammonia, the residual carbon monoxide in the nitrogen-hydrogen mixture being removed by conversion over a catalyst into methanol and thus purifying the gas mixture for ammonia synthesis with a simultaneous production of a valuable product. Figure 4 shows the annual production of methanol and ethanol in the United States with estimates of the 1930 production of methanol. The top line gives the total production of methanol both from wood distillation and by highpressure synthesis. The lower line, beginning in 1927, shows the rapid growth in output of synthetic methano!, which it is expected will reach the production of 10 million gallons this year. As is shown in Figure 5 , the market price of methanol has come down rapidly. It is now selling at the same price as denatured alcohol. The distribution of the two alcohols is shown in Figure 6. The chart does not show the use of methanol as an antifreeze in automobile radiators, which use is now assuming large proportions. Methanol has several advantages over denatured alcohol for this purpose. Although its boiling point is lower, it evaporates more slo~vly,on account of its lower
799
molecular weight. from solution in water in all dilutions and at all temperatures; 7 5 parts of pure methanol have the same antifreeze effect as 100 parts of denatured alcohol. As the pure methanol sells for the same price as denatured alcohol, its use in automobile radiators is therefore not only better but niuch cheaper. A possibility that has been often discussed, but that has not so far come to anything, is the‘use of methanol as a motor fuel. Methanol as a cheap raw material is now available and promises to be an interesting starting point in many organic syntheses. For years the possibility of making higher alcohols by highpressure synthesis has been discussed, but production on a, commercial scale has nowhere been undertaken until comparatively recently. The Du Pont Ammonia Corporation has regularly been producing large quantities of higher alcohols by high-pressure synthesis from water gas along with its manufacture of methanol for the past year or two, but has previously made no public announcement of this fact, S o w , however, a large plant costing several millions of dollars is nearing completion and will soon be in operation with important production of higher alcohols primarily for consumption by the du Pont Company as solvents in the manufacture of DLKOand other lacquers and thinners. The higher alcohols produced contain about 80 per cent of butyl and amyl alcohol, the remainder being propyl alcohol and also alcohols higher than fire-carbon alcohol. The use of the butyl-amyl fraction is self-evident. New uses are desirable for the proper disposition of the propyl fraction and .of the highest fraction. I t is believed that these new products of synthetic chemistry will find important new uses, and mixtures of hexyl. heptyl. and octyl alcohols will now be commercially available. Finally, the question niay be asked-what other compounds will be produced by high-pressure synthesis? To this question I am not prepared to give a definite answer. hlany possibilities exist. h tremendous amount of research work is being carried on. Research work a t high pressures is a very costly proceeding. The equipment necessary to try out a new idea always represents a considerable investment. The large synthetic ammonia companies I believe-at any carrying on large research rate I can speak for one-are programs. Elaborate and costly seini-works plants have been installed for experimental purposes; the American highpressure synthetic chemical industry is ready to undertake new syntheses when these are feasible.
Liquefied Petroleum Gases Xarketed production of liquefied petroleum gases during 1929 reached a total of 9,925,698 gallons, a n increase of 120 per cent over t h e 4,522,899 gallons marketed during 1928, according t o the Cnited States Bureau of Mines, through which the first quantitative data on this recent development in the petroleum industry have been assembled. Information received from representatire producers regarding shipments during the first five months of 1030 indicates that the rate of growth estahlished during 1929 is being continued. Of the 1929 distribution, 113,080 gallons were shipped outside the United States, principally to Canada and the Hawaiian Islands. The production of Pintsch gas, a compressed gas made by cracking oil and used principally as a n illuminant; the manufacture of Blau gas, a liquefied petroleum gas made from gas oil; and the extraction and liquefaction on a relatively small scale of some of the lighter fractions of casinghead gasoline constitute a background, extending over approximately half a century, for the recent developments in the commercial manufacture and sale of liquefied petroleum gases. I n the present stage the natural gasoline extracted from natural gas is the principal source of the lighter hydrocarbons suitable for liquefied-petroleum-gas manufacture, although the refinery gases resulting from various oil-distillation processes constitute a potential source. The need of petroleum refiners for more stable grades of
natural gasoline necessitated the removal of more volatile fractions of the raw casinghead gasoline. This was accomplished originally by “weathering,” but in recent years the use of fractionating columns for the separation of the fractions has permitted their recovery and utilization for domestic and industrial purposes. These lighter hydrocarbons occupy the intermediate zone between the so-called permanent gases and ljquids. They remain in liquid form when under pressure but are gases a t atmospheric pressure and normal temperatures. Consequently they may be stored and transported as liquids under pressure in special cars, tanks, wagons, and cylinders and used as gases a t atmospheric pressure. Propane and the butanes form the compounds in the liquefied petroleum gases now definitely established, but pentane, a liquid a t average temperatures, was included in the survey to the extent that i t is marketed for purposes similar to the two lighter fractions. The record of the production of liquefied petroleum gases may be extended as far back as 1912, when Blau gas was established as a commercial product but, as such a record would in part indicate the operations of individual companies, the following record of marketed production starts with 1922, the period during which three or more companies were annually engaged: 1922, 222,641 gallons; 1923, 276,863 ; 1924. 376,488; 1925, 403,074; 1926, 465,085; 1927, 1,091,005; 1928, 4,522,899; and 1929, 9,925,698.
