The Strengths of Electric Heat When Compared with Heat from Fuel

Posted By Richard Jefferson on 03 December 2014

Posted in The Vintage Machinery Almanac

This article was originally published in Electrochemical and Metallurgical Industry Publication of August 1907. Information within this article is therefore correct as of 1907. The publication of this material aims to provide historical insight on the subject and its place in industry.

This is article is a continued discussion on Electric Heat Versus Heat From Fuel

It is, of course, clear that the previous comparison is exceedingly narrow in that it considers 'only one single side of the problem, namely, the amount of fuel and electrical energy required to produce the same number of calories. But even in this very respect the above comparison falls short of the truth and does not do justice to the electric furnace. The chief reason is that electrical heating is essentially internal pleating, permitting a very high concentration of energy at any point wanted and thus enabling one to produce high temperatures. Fuel heating, on the other hand, is always more or less transmission of heat from the fuel to the charge, and the rate of heat transmission depends on the difference of the two temperatures; this rate decreases rapidly the higher we go up in the temperature.

Naturally, with fuel heating we can never obtain any higher temperature than that of the burning fuel itself. There is no corresponding limitation in electric heating. This is the fundamental reason why for all very high temperature processes the electric furnace reigns supreme. This is an established fact, but since electric reduction of iron ore does not fall into this class of processes, we may not further discuss them here, except by pointing out that the possibility of obtaining higher temperatures might be found useful for special cases of iron ores; for instance, with titaniferous slags. It is of greater importance perhaps to refer to the fact established at the Sault Ste Marie experiments that iron ores containing a high sulphur contact can be successfully smelted in the electric furnace so as to get a pig iron containing only a few thousandths of 1% of sulphur. Through the electric furnace certain iron ores will therefore become available for the production of pig iron which heretofore could not be treated economically. This will probably become more important in future years than it seems to be at present.

With respect to the reducing agent it was stated above that the same amount of carbon as reducing agent is required in the electric furnace as in the blast furnace to rob a certain amount of iron oxide of its oxygen. This is perfectly true, but it would be absolutely wrong to conclude that the electric furnace has therefore no advantage in this respect over the blast furnace. The point is that the blast furnace requires coke, while charcoal or peat coke will does very well in the electric furnace. This point is at the bottom of the whole situation in California. On account of coke not being available, California has not had its own pig iron industry. At the new plant on the Pitt River there is unlimited timber for charcoal making. Viewed from every point the undertaking of Mr. Noble looks promising, especially if we consider that pig iron sells in San Francisco at about $10.00 more than in Pittsburg. Let us hope that the work which was officially inaugurated on our national holiday, the Fourth of July, will turn out commercially successful. It would be a matter of great industrial importance for California and could stimulate similar progressive work in other districts where the conditions appear sufficiently favorable for electric smelting and metalworking, plus sufficiently different from the conditions in our present blast furnace centers.

Image Credit: The Library of Congress