February 4, 1916. THE COLLIERY GUARDIAN. 221 present moment. Some years ago it appeared as if the combination of the gas producer and internal combustion engine would soon out-distance the boiler and steam engine, partly because of the then much superior thermal efficiency of the internal combustion engine, and partly, also, because of the capacity of the gas producer to gasify low grade coal under ammonia recovery conditions; two very important considerations. On the other hand, the capital outlay and the ground area involved in the erection of an ammonia recovery gas producer plant, as compared with a boiler installation, have hitherto formed formidable obstacles to the extension of the system. Attempts are being made, which I trust will prove successful, to overcome this disadvantage, and a type of ammonia recovery plant is now offered to the public which claims to have succeeded; and if the result of independent investigation and a sufficiently long experi- ence of its working confirm this claim, an important step forward will have been achieved. One of the principal losses in connection with steam raising from coal is due to the low efficiencies and evaporative power of the best types of coal-fired boilers; and, moreover, until recently gas-fired boilers have been so inefficient that their use on a big scale was out of the question, except where large surpluses of gas were avail- able, which would otherwise be wasted. But the inven- tion of the method of burning gases flamelessly in con- tact with incandescent surfaces has provided a means of achieving both very high efficiencies and evaporative powers with gas-fired multitubular boilers on a large scale. The following table shows the comparative heat balances obtained in actual trials of (1) a large “ surface combustion ” multitubular boiler fired by coke oven gas of net calorific value 510 British thermal units per cubic foot at N.T.P.; and (2) a marine boiler fired with a good steam coal of net calorific value of 13,800 British thermal units per pound (volatile matter = 16-1 per cent.). Gas-fired Heat utilised surface combustion boiler. 92*7 Coal-fired main boiler. 75*1 Heat lost— In burnt gases .. 3’07 18*1 *) In unburnt gases, &c. Nil. > 7*3 2*8? 24*9 By radiation 4*3j 4*0 J ■ 100*0 ... 100*0 With the possibility, now within reach, of achieving such high thermal efficiencies in gas-fired boilers, the lecturer ventured to suggest an alternative scheme, which would combine the advantages of the gas pro- ducer, with its capacity of dealing with low-grade fuel under ammonium recovery conditions, with the high efficiency of the modern steam turbine. The raw coal would, in the first instance, be gasified in a producer under ammonium recovery conditions; the resulting gas would then be burnt in a surface combustion boiler, whose efficiency with producer gas may be put down at certainly not less than 85 per cent. Finally, steam could be turned into a steam turbine of assumed 27 per cent, efficiency, yielding a net result of 17-3 per cent, in respect of power on the available energy of the coal consumed, phis 801b. of ammonium sulphate per ton of coal. From the point of view of size of units, the turbine has shot far ahead of its rival; the big Parsons turbo- alternator recently installed at Chicago is of 35,000 horse-power capacity, far surpassing anything yet attempted with an internal combustion engine unit. Whereas, also, a gas engine only works at its highest efficiency with a high load factor, a turbine maintains its efficiency over a wider range of load than its rival, and at low loads far surpasses it. A gas engine requires much more lubrication, but, on the other hand, usually less cooling water than the turbine, and, owing to its simpler construction, the turbine requires less adjust- ment and repairs, and is more reliable than its rival. These considerations have led to the almost universal adoption of the steam turbine for big power stations, except in cases where there are available supplies of surplus gases from coke ovens, blastfurnaces, or the like. On the other hand, for comparatively small units (say, up to 2,000 horse-power), where the load factor is uniformly high, and not subject to abrupt variations, the gas engine has certain advantages. In any case, however, the choice between the two rival systems will not usually be determined upon purely thermal con- siderations, but upon other equally important factors. It is clear, however, that if we are to achieve all the economies in respect of power production which modern engineering has made possible, two things must be brought about by some means or other. Firstly, the owners of existing inefficient plants must, supposing their requirements be large enough to justify their using a separate generating plant, be prepared to put them on the scrap heap without remorse, and, if necessary, the State might advance a portion of the money required to substitute a really efficient plant, on -reasonable terms. Secondly, in order to meet the necessities of the innumerable class of relatively small consumers, the whole question of the organisation of public power schemes for the generation and distribution of electrical energy in the most efficient manner, and at the lowest possible cost, should be taken up. Hitherto, local jealousies and vested interests, which our lawyer-ridden Parliament has fostered far too much, have blocked and are still blocking the way. How often in the past, in connection with water, gas, and electric light schemes, has Parliament encouraged the formation of small rather than of large and more efficient undertakings, a policy which has proved as disadvan- tageous to the community at large as it has been profitable to the lawyers who frequent the Parliamentary Bar. The average size of the generating stations is only 5,285 kw., and of the generating engine units only 632 kw.; many of the older stations still contain reciprocating engines, and some have even to cart their coal, a truly ridiculous state of affairs. But notwith- standing these disadvantages, London’s demands for current per head of population have increased five-fold since I960, and are still expanding. (The lecturer then described the North-East Coast power scheme, an account of which appeared in the Colliery Gziardian for July 7, 1911.) Public Supplies of Gas for Industrial Purposes. The larger users of gaseous fuel will doubtless con- tinue to find it cheaper and belter to generate “ producer gas,” by the complete gasification of coal and coke on their own premises, than to purchase gas from any public company. But there remain a very large number of industrial consumers wdiose individual needs for gas are not big enough to warrant the installation of a separate gasification plant, but whose requirements con- stitute in the aggregate a very large and important demand, which can only be met economically by a public supply company. Some of the large towns gas works, situated in industrial areas, are taking up the matter with great energy and success. Thus the Birmingham Corporation have installed a splendid system of high-pressure qos distribution throughout its industrial area, and before tie war it was supplying manufacturers with coal gas, at a pressure of 12 lb. per sq. in., at a net price varying between ll*4d. and 15*2d. per 1,000 cu. ft. During the year ending March 31, 1913, no less than 1,900 million cu. ft. of gas (or 22-j- of the city’s total output) were sold in Birmingham for industrial purposes. It is largely used for aluminium and brass and lead melting in crucible furnaces, for the hardening, tempering, and annealing of metals, for the annealing of glass, and the like. The Sheffield United Gas Company have been no less enterprising; thus in 1913 the smallest consumer in Sheffield paid no more than 15d. per 1,000 for his gas, and consumers using more than 500,000 cu. ft. per annum were charged 12d. per 1,000 for all gas between the first half million cubic feet -and six million cubic feet per annum, and only lOd. per 1,000 for anything in excess of the last-named quantity. This enlightened policy has led to a considerable use of coal gas in some of the Sheffield steel works, chiefly for the hardening, tempering and annealing of special steels (including tool steels), and for file forging, all of those operations in which accurate temperature control is a matter of vital importance. One works alone was using 18 million cu. ft. per annum in connection with the manufacture of agricultural implements. Fuel Economy in the Iron and Steel Industries. The history of research and invention in relation to fuel economy in the iron and steel industries, since James Neilson, manager of the Glasgow gas works, introduced his revolutionary idea of using hot blast in the smelting of iron in 1829, is veritably a romance to be handed down to posterity as perhaps the finest record of British creative achievement in the domain of applied science during the 19th century. Its concluding chapter relates more particularly to the utilisation of blastfurnace and coke oven gases in the manufacture of steel. And although it is a chapter to which British, Belgian, and German chemists and engineers have equally contributed during the past 20 years, I should like to mention especially the name of the late Adolphe Greiner, the distinguished head of the Cockerill Works at Seraing, near Liege, to whose enter- prise the world principally owes the development of the large gas engine for dealing with blastfurnace gas, and whose recent death, after a year’s bitter experience of German invasion, all British metallurgists deplore. According to Mr. Beilby, no less than 28 million tons of coal were consumed in British iron and steel works in the year 1903 for an output of 8-93 million tons of pig iron, and 5-31 million tons of steel. An unofficial esti- mate for the year 1911 gives a consumption of 19-2 million tons of coal in respect of the production of 9-7 million tons of pig iron (or approximately two tons of coal per ton of iron), which does not, however, include the additional fuel used in the conversion of iron into finished steel section. Making due allowance for this, it would appear that the total fuel consumption in British iron and steel industries in that year wrould probably not be much less than 30 million tons, which would work out at about two tons per ton of pig iron, plus two tons per ton of finished steel produced. The British iron and steel industry still labours under a disadvantage compared with its German rival, on account of its much earlier development. We built most of our blastfurnaces and rolling mills during the iron age, when it mattered little whether or not the smelting of iron was carried out on the same site as the subse- quent manufacture of rails and plates. The modern German industry, on the other hand, took its rise after the invention of the basic steel process, when the great advantages of a close proximity of blastfurnaces, steel works and rolling mills, were so manifest, that all subse- quent installations of plant were expressly planned and laid out so far as to secure them. Consequently, whereas all the great German works erected during the past 30 years have from the outset embodied and profited by these advantages, many of the older British plants have had to be gradually re-modelled, as circumstances permitted, so as to conform as far as possible to the new conditions; such a process necessarily takes time, and there are still some of our works that have not yet completed the change. In times past, for every ton of iron produced at the blast furnace, 1*6 tons of new coal had to be coked at the colliery, and an additional 0-75 ton at least had to be sent to the steel works and rolling mills, entailing in all an expenditure of not less (and often more) than 2*35 tons of raw coal per ton of finished steel section produced, Now the natural laws and conditions governing the reduction of the iron ore in the blast furnaces, which were formerly not so well understood as now, are such as make it impossible to utilise in the furnace itself more than about one-third of the energy of the coke charged into it, plus the energy of the hot air. The remaining two-thirds leaves the furnace partly as heat in the molten iron and slag, but mainly as combustible gas. Thus for every ton of iron produced some 168,000 cu. ft. of gas, containing from 28 to 30 per cent, of carbon monoxide and about 1 per cent, of hydrogen, leaves the furnace, the potential energy of which is about 45 per cent, of that of the coke charged into the furnace. a Blast Furnace. Heat Balance of Heat of combustion of coke ................ = 90 Sensible heat of blast = 10 100 Heat utilised in furnace = 30 Heat of combustion of gas................... =45 Heat in molten slag and iron ................. =15 Radiation o r other losses ............... =10 100 About 60 per cent, of this gas could be utilised for generating and heating the blast, but the balance of 40 per cent, was a surplus for which no further use could be found, unless the plant either adjoined and was worked in conjunction with the steel works, which was not 'always or often the case, or (as was only possible ’within recent years) an independent power company was at hand to purchase it. Hence the blast furnace manager had no particular interest in the gas beyond that portion of it which could be utilised on his plant, and it mattered little to him how much was lost by leakages, or how inefficiently it was burnt under his boilers, for he always had more than enough of it. But the rapid development during the past 15 years of the big gas engine in relation to blast furnace gas, which we owe chiefly to the pioneering labours of Belgian engineers during the year 1896 to 1900, and later also to German enterprise, has entirely changed the whole complexion of the case, and inaugurated a new era in fuel economy of which we, in this country, at any rate, are only beginning to reap the benefit. It has been my privilege during recent years to see these new possibilities demonstrated at the Skinningrove Iron and Steel Works, which have been remodelled and extended under the direction of my relative, Mr. T. C. Hutchinson. The cardinal feature of this new development is the concentration of by-product coke ovens, blast furnaces, steel works, and rolling mills in one plant, coupled with the utilisation of the combined surpluses of coke oven gas, and cleaned blastfurnace gas partly in big gas engines driving dynamos generating electrical energy for driving the rolling mills and all other machinery on the plant, and partly also to displace producer gas as the fuel for the steel furnaces and soaking pits. In this way it has been proved possible to take in ironstone at one end of the works and to turn out finished steel sections at the other, using no more coal than must be charged into the coke ovens to make the necessary amount of coke for the blast furnaces. And even after all this has been achieved, as it shortly will be, we look forward to the time when, with smaller leakage at the bells of the blast furnace, and more efficient turbo-blast engines, there may be still a surplus of power over and above all the requirements of the plant for disposal outside. Translated into figures, this means that, whereas under the old plan it was necessary to consume altogether not less than 2-35 tons of coal per ton of iron converted into finished steel sections, it is now possible under the new arrangement to effect the same ultimate result with an expenditure of no more than 1-6 tons of coal, or, in other words, to effect a net saving of 0-75 ton of coal per ton of iron produced. And if this were universally achieved, it would involve a saving equivalent to about one-third of the 30 million tons of coal annually consumed in British iron and steel works at the outbreak of the war. But even the universal achievement of these new reforms will not exhaust all the possible economies in the production of iron and steel; there will still remain to be dealt with at least one prominent item of present loss, namely, the heat contained in the molten slag running from the blastfurnaces, which is probably equivalent to between 8 and 12 per cent, of the calorific value of the coke charged into the furnaces, according to the richness and character of the ore smelted. The problem of turning this to good account is beset with technical difficulties, but already a beginning has been made, in at least one British establishment, to deal with all details, and success will be eventually achieved. The last Royal Commission on Coal Supplies reported in 1905 the possible saving in our then annual coal con- sumption amounted to between 40 to 60 million tons. And, if my rough estimate is anywhere near the mark, the margin is probably not much less to-day. Truly, in matters of national saving, we “strain at gnats and swallow camels.” There is no excuse for the inaction of our rulers during the past 10 years, because the report of the Royal Commission was ‘ ‘ presented to both Houses of Parliament by command of his Majesty.” But those were the piping days of peace and plenty, when we thought but little of the morrow. Now that war has brought us face to face with the stern realities of the case, let it not be said to our shame by posterity that we knew our duty in the matter and did it not. ■ The special committee appointed by the Liverpool Chamber of Commerce to consider the proposals drawn up by Mr. A. M. Samuel, member of the council of the Association of Chambers of Commerce, for formulating a British trade policy after the war, has reported in favour of the creation of a'Ministry of Commerce, the registration of firms, the establishment of credit banks, a tariff system, the taxation of imports, and reciprocity between the Empire and the Allies.