Argon gas and its usage in Steel Plant...

Argon gas and its usage in Steel Plant Argon (Ar) gas is present in very small percentage in the atmosphere. Argon is very inert and hence it is referred to as one of the noble gases. It is not known to form true chemical compounds. It makes a good atmosphere for working with air sensitive materials since it is heavier than air and less reactive than nitrogen gas. Argon gas is the most abundant of the noble gases. It is a non-reactive component of the atmosphere. It constitutes 0.934 % by volume and 1.288 % by mass of the earth’s atmosphere. Argon was suspected to be present in air by Henry Cavendish in 1785 but was not isolated until 1894 by Lord Rayleigh and Sir Willam Ramsay at University college London in an experiment in which they removed all of the oxygen, carbon dioxide, water and nitrogen from a sample of clean air. Argon gas is produced by the fractional distillation of liquid air at the cryogenic air separation plants. It is produced, most commonly, in conjunction with the manufacture of high purity oxygen using cryogenic distillation of air.  Since the boiling point of argon is very close to that of oxygen (a difference of only 2.9 deg C) separating pure argon from oxygen (while also achieving high recovery of both products) requires many stages of distillation. For many decades, the most common argon recovery and purification process used several steps namely (i) taking of a side-draw stream from the primary air separation distillation system at a point in the low-pressure column where the concentration of argon is highest, (ii) processing the feed in a crude argon column which  returns the nitrogen to the low pressure column and produces a crude argon product, (iii) warming the crude argon and reacting...

Nitrogen gas and its usage in Steel Plant...

Nitrogen gas and its usage in Steel Plant Nitrogen is a non-reactive component of the atmosphere which is not life supporting. The percentage of nitrogen in air is 78.06 % by volume or 77 % by weight of the air. The composition of air is shown in Fig 1. Fig 1 Composition of air The element nitrogen was discovered as a separable component of air, by Scottish physician Daniel Rutherford, in 1772. Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air. Nitrogen is produced in large quantities and at high purity as a gas or liquid through the liquefaction and distillation of ambient air at the cryogenic air separation plants. It is also produced on commercial scales as a lower purity gas by adsorption technologies (pressure swing adsorption, PSA), or diffusion separation processes (permeation through specially designed hollow fibers). Gaseous nitrogen is called in short as GAN while the liquid nitrogen is called in short as LIN. Liquid nitrogen is a cryogenic liquid. Cryogenic liquids are liquefied gases that have a normal boiling point below – 150 deg C. Liquid nitrogen has a boiling point of -195.8 deg C. Because the temperature difference between the product and the surrounding environment is substantial, it is necessary to keep the liquid nitrogen insulated from the surrounding heat. Nitrogen is often stored as a liquid, although it is used primarily as a gas. Liquid storage is less bulky and less costly than the equivalent capacity of high-pressure gaseous storage. A typical storage system consists of a cryogenic storage tank, one or more vaporizers and a pressure control system. The cryogenic tank is constructed, in principle, like a vacuum flask. There is an inner vessel...