Improvements in and relating to processes of making nitric acid
Реферат: 150,836. British Thomson - Houston Co., (General Electric Co.). June 17, 1919. Nitric acid. - Oxides of nitrogen are absorbed in nitric acid with a concentration from 60 to 70 per cent, and cooled to a low temperature, namely, in the region of -40‹ C.; and free nitrogen and hydrogen collected as byproducts at certain stages in the process are combined to give the liquid ammonia used to cool the absorption chamber. Fig. 1 shows apparatus in which oxides cf nitrogen are produced by the catalytic oxidation of ammonia in the reaction chamber 1, and are conveyed to the absorption column 3, which is provided with a jacket containing liquid ammonia, and is packed with acid-resisting material such as coke. Rapid evaporation is effected by the exhaustion apparatus 18, and the resulting gaseous ammonia is supplied to the oxidizer 1. Nitric acid is allowed to percolate down the column from the nozzle 27. Unabsorbed gases pass on to a " scrubber " 11, which may consist of a tower, packed with coke, and supplied with a downward stream of water. The solution of the oxides of nitrogen in nitric acid then passes to the heat interchanger 29, through pipes 31 to the electrolyzing-cell 30, at the anode of which the oxides of nitrogen are oxidized to nitric acid. Hydrogen is liberated at the cathode, which is separated from the anode by the partition 36, and with the nitrogen passing from the scrubber 11 is used to from ammonia. Periodically, nitric acid is withdrawn from the cell 30, and replaced by water, and by means of the pump 33, nitric acid is supplied to the tower 3 passing through the heat interchanger 29 on its way, and thereby warming the cold nitric acid solution of the oxides of nitrogen coming from the absorption tower. In a modified system, the absorber, Fig. 2, consists of a chamber in which a number of disks 58 dip into a series of compartments 57 kept just filled to overflowing with nitric acid supplied by the conduit 25 from the electrolyzing-cell. The acid thus passes in the opposite direction to the flow of gases from the oxidiser, and is cooled as before with liquid ammonia. The gases coming from the oxidizer may be shunted to a condenser in order to reduce the water content before entering the absorption chamber.
System for evacuating nox gases from a nitric acid storage tank
Номер патента: CA3209545A1. Автор: Ronald Rösler,Andre De Smet. Владелец: Yara International ASA. Дата публикации: 2022-12-01.