Novel magnesium nitrate method based concentrated nitric acid production system

Abstract

The invention belongs to the technical field of chemical engineering, and particularly relates to a novel magnesium nitrate method based concentrated nitric acid production system which comprises a nitric acid concentration tower and a bleaching tower. Dispersers positioned at the top of the nitric acid concentration tower and the top of the bleaching tower are groove-type dispersers, the sprinkling aperture of the disperser at the top of the nitric acid concentration tower is 6mm, and the sprinkling aperture of the disperser at the top of the bleaching tower is 4mm. The height specification of two tower sections of the nitric acid concentration tower is 15300mm. Compared with a traditional disperser of a disc type structure, the novel magnesium nitrate method based concentrated nitric acid production system has the advantages that the spraying density can be increased, column flow is prevented from being generated during spraying, the gas-liquid contact area is increased, mass transfer and heat transfer between gas and liquid are improved, and the nitrate content of dilute magnesium nitrate is reduced; and compared with the traditional tower section specification and the nitric acid concentration tower with the height of 14900mm, the system has the advantages that the rectification height of the concentrated nitric acid is increased to stabilize the concentration of the finished product acid to be more than 98.2% (w / w), meanwhile, the denitration height is increased, and the nitrate content in the dilute magnesium nitrate is reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a novel concentrated nitric acid production system by the magnesium nitrate method. Background technique [0002] The magnesium nitrate method concentrated sulfuric acid production process refers to the process of using magnesium nitrate solution as a dehydrating agent to distill dilute nitric acid to produce concentrated nitric acid (concentration is more than 97.2% (w / w)). But, the concentration of the concentrated nitric acid that existing magnesium nitrate method concentrated sulfuric acid production technique produces fluctuates between 97.2-98.5% (w / w), can not be stable more than 98.2% (w / w); % (w / w) fluctuates and cannot be stabilized below 0.5% (w / w), so it cannot meet the requirements of customers with concentrations above 98.2% (w / w) and nitrates below 0.5% (w / w) long-term needs. [0003] The dilute magnesium nitrate contains nitrate between 0.2...

AI Technical Summary

Problems solved by technology

But, the concentration of the concentrated nitric acid that existing magnesium nitrate method concentrated sulfuric acid production technique produces fluctuates between 97.2-98.5% (w / w), can not be stable more than 98.2% (w / w); % (w / w) fluctuates and cannot be stabilized below 0.5% (w / w), so it cannot meet the requirements of customers with concentrations above 98.2% (w / w) and nitrates below 0.5% (w / w) long term needs

[0003] The dilute magnesium nitrate contains nitrate between 0.2~0.3% (w / w) in production, because the dilute magnesium nitrate contains high nitrate, causes serious corrosion of magnesium nitrate heater, just needs to be replaced in 3~4 years, makes production cost rise; Production The tail water containing 2 to 3% (w / w) magnesium nitric acid produced in the process is sent to the neutralization tank, initially neutralized with 30% (w / w) liquid sodium hydroxide, and then sent to the terminal water treatment device of the factory for further treatment. After the treatment is qualified, some enterprises with dilute nitric acid equipment have been transformed to send part of the magnesium tail water to the absorption tower of the dilute nitric acid equipment as an absorbent, which reduces the treatment capacity of magnesium tail water, but there is still a large amount of magnesium tail water that needs to be neutralized Treatment, the neutralization treatment of magnesium tail water not only causes environmental pollution, but also increases production costs; the lack of nitrogen oxide gas generated during production and the trace amount of nitrogen oxide gas discharged from tanks at high altitudes pollute the environment

Images