BENZOLE AND CORROSION.
Page 2
Page 3
If you've noticed an error in this article please click here to report it so we can fix it.
IT IS WITHIN our knowledge that certain statements, equivalent in their nature and effect to ' insidious propaganda, are being made to the effect that the use of benzole results in. acid corrosion of the leaves and internal parts of the engine. That this •is not the case is demonstrable both on theoretical and practical grounds.
Taking the former first, there is, as is common knowledge, a very small proportion...of, sulphur in commercial, benzole'. This sulphur, on• being 'burned in the presence of oxygen, whicheoccurs when the benzole and airmixture is exploded, in the cylinder, forms sulphtir di-oxide. Sielpb,ur di-oxide dissolved in water is sulphuric acid, andfif this formation and solution actually occurred within the cylinder, there is no doubt that its effects, particularly on the valves and seatings, would very soon be apparent. Water is, of course, one of'the products of combustion, so that we certainly have in the cylinder, after the explosion, all the constituents of aulphurie acid. But the water is still, within the cylinder, in existence only as vapour at a considerable temperature. The acid does not form until this vapour condenses, and this cannot occur in the engine cylinder, except in extremely unfavourable circumstances such as would seldom happen. The temperature is always sufficient to prevent condensation.
A little of the water vapour condenses by the time it gets to the silencer, and, after a oonsiderable period of use, certainly not less than about a year, would have the effect of eating away the interior of this component. The renewal of certain portions of the silencer once a year is an insignificant matter. Later on it would be obviated by the provision of silencers specially designed to withstand the effects of the acid. In any event such a disadvantage is very much lower down in the scale of importance than would be the corrosion of the engine pasts. Now as to practical demonstration. The actual standard to which benzole is to be marketed is. not yet, we understand, finally decided upon by the Benzole Supply Association, but it is practically certain that the maximum quantity of sulphur which will be allowed to be present will be 250 grains to the gallon.
Some years ago, a pioneer advocate of benzole as a fuel for motorcars—he is a coke oven manager—put down a small washing plant for purifying some of the benzole which was obtained as a by-product from his coke ovens, and persuaded the directors of his company to use this, at that time almost unheard-of* motor fuel. He was washing the benzole to such an extent that he was reducing the sulphur content to about the quantity we have stated, namely, 250 grains to the gallon. Turning the matter over in his mind, he came to the • conclusion' which we have already stated, that it was very unlikely that any ill effects would be noticeable if this proportion of sulphur was greatly increased, and, therefore, without mentioning the matter to anyone, he suddenly ceased to wash his benzole, the result being that it was going into the cars having as much as .900 to 1000 grams of sulphur to the gallon. The use of the benzole in this state was continued for some months, and no complaint was made by the users and owners of the cars in which the fuel was used. Some of the cars were taken down for the customary cleaning of the cylinders and piston heads, and still no deleterious effect due to the benzole was remarked, and, finally, he confessed his delinquency and had a special examination made of one of the engines, and it was clearly demonstrated that this excess of sulphur had no ill effect on the engine whatever, nor, in the period covered, perhaps six or eight months., was there any noticeable 'corrosion even in the silencer.
The conclusion must not be drawn, from this statement, that we are in favour of any greater percentage of sulphur than the 250 grams per gallon being permitted, but our objections are on entirely different grounds. Most of the sulphur di-oxide which we have stated is formed in the cylinder emerges with the exhaust. In the small volume which would result from the benzole having 250 grains of sulphur to the gallon, this would hardly be noticeable, but as the sulphur content increases, and as the use of this benzoic increases, then it is likely that the presence of this obnoxious gas would be detectable in the atmosphere, and particularly in some of the more congested streets, or during temporary blocks in the traffic.