Method and equipment for producing polyphosphoric acid with wet process phosphoric acid

Abstract

The invention belongs to the technical field of phosphoric acid production in the inorganic chemical industry, and relates to a novel production method and equipment for producing polyphosphoric acid with wet process phosphoric acid. According to the method, a reverberatory furnace is mainly adopted innovatively, the equipment such as a burner nozzle, a polyphosphoric acid tank, a low polyphosphoric acid circulating pump, a fume extractor, a filler washing tower and a plurality of control valves is additionally arranged, and the wet process phosphoric acid is used as a raw material for concentrated polymerization production of the polyphosphoric acid. The reaction equipment is reliable and stable, and easy and convenient to operate and control, and solves the problem that scales easily deposit on tubes of a tubular heat exchanger in single-stage or multi-stage evaporation of the wet process phosphoric acid and are stubborn at home and abroad at present. Temperature control is moderate, and the phenomenon that a large number of acid particles are carried away due to local overheating and excessively high temperatures is avoided. No vacuum mode is required, and energy is saved. Two-stage product output is adopted, thereby facilitating the improvement on the production efficiency. Tail gas is recycled by a cleaning solution which then is used as a raw material, the product yield is increased, exhaust emission is reduced, and the environmental protection is facilitated.

Description

technical field

[0001] The invention belongs to the technical field of phosphoric acid production in the inorganic chemical industry, and relates to a method and equipment for producing polyphosphoric acid from wet-process phosphoric acid. Background technique

[0002] Polyphosphoric acid is a fine phosphorus chemical product, and its main components are orthophosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid and high polyphosphoric acid. Molecular formula: H (n+2) P n o (3n+1) ;

[0003] Structural formula:

[0004] Typical product molecular formula: H 6 P 4 o 13 . The phosphoric acid content of polyphosphoric acid is generally 105-115%H 3 PO 4 . Polyphosphoric acid has low viscosity and freezing point, less corrosion, and has a good chelating effect on metal ions. It is mainly used in petrochemical condensation catalysts, dehydrating agents, metal surface treatment agents, analytical reagents, pharmaceuticals, organic Synth...

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