Sulphur in Diesel Fuels

Abstract

Sound reasons exist for the current interest in the sulphur content of Diesel fuels and the authors give a brief historical account of the recognition of its undesirable effects. Notwithstanding that it is, technically, quite feasible to desulphurize the fuels, other considerations compel the acceptance of a significant sulphur content for some time to come, and it may be expected that, as a result, engine wear and fouling will be accentuated unless appropriate precautions are taken. Engines of different types and design will be differently affected. An account of relevant physico-chemical reactions of sulphur in the engine focuses attention on the trioxide produced during combustion as the principal cause of ill effects. Amongst precautionary measures, certain beneficial rules of engine operation (particularly as regards coolant temperature) and design are proposed. Importance is attached also to metallurgical expedients such as chromium plating, and to the use of special additive-type lubricants. It is thus made evident that by suitable design, operation, and lubrication of the Diesel engine, it can be made to consume fuels of a higher sulphur content than has hitherto been usual, without adverse results. Instances of the satisfactory use of an actual crude oil containing 3 per cent sulphur and an under-boiler fuel oil of 2–5 per cent sulphur content are given.