SAFE DESIGN AND OPERATION OF LIQUID AND GASEOUS OXYGEN SYSTEMS

摘要

Oxygen is a fluid that has numerous uses in industrial and scientific applications. Welding, steel-making, cryogenic rocket propulsions are some examples. Oxygen poses serious fire hazard, which may be violent and destructive. It is important for the engineers engaged in design and operations of oxygen systems to have very clear knowledge on the aspects that cause the ignition and combustion due to the presence of excess oxygen in the surrounding. In this paper, direct ignition sources such as friction, heat of adiabatic compression, heat from mass impact, heat from particle impact, static electric discharge, and resonance in cavities have been discussed in sufficient details, indicating very clearly the ways to avoid them. Indirect ignition sources have been mentioned. The metals (metals and alloys) and non-metals (sealants and lubricants) that could be safely used in oxygen systems and the ways oxygen-compatible components and systems could be designed have been discussed in this paper wherever opportunity arose. Some basic guidelines in safe designing of oxygen system have been noted. The safe operating conditions for oxygen systems, such as pressure and velocity, temperature, flow-rate, concentration and geometry have been discussed. The famous CGA velocity curve with its usefulness and limitations have been discussed in detail. From this paper, the reader will get a fair idea of the constraints involved in designing of pipelines, valves, filters, component-manufacture, system layout and required control in system operation for incident- and accident-free handling of gaseous and liquid oxygen systems. The information given in this paper is often qualitative, because the large volume of data needed to be considered during the design of an oxygen-safe component and system are very exhaustive and beyond the scope of this paper.