Method for large-scale production of high-purity diphosphorus pentoxide

Abstract

The invention discloses a method for large-scale production of a high-purity diphosphorus pentoxide product by taking yellow phosphorus as raw material. According to the method disclosed by the invention, a molecular sieve is adopted for temperature swing adsorption of dry air in a production process, and compared with a traditional sulfuric acid drying process, the method disclosed by the invention is significantly improved in drying effect, the influence of water and sulfate radicals on the product quality is avoided, and the product purity is greatly improved; in addition, produced high-temperature flue gas performs indirect heat exchange with soft water, the soft water is vaporized to generate steam so that heat is recovered, and gas-state diphosphorus pentoxide is cooled to obtain the solid diphosphorus pentoxide product; and the flue gas in a tower body performs indirect heat exchange with the external soft water, so that the tower wall is in a low-temperature state environment, the high-temperature corrosion of the tower wall of equipment is avoided, the service life of the equipment is prolonged and the production strength and the productivity of the equipment are upgraded. By adopting the method disclosed by the invention, the problems of small production scale, low product purity, high investment, high loss of heat energy, serious high-temperature corrosion and unstable product quality in the existing production process of diphosphorus pentoxide are effectively solved, and the safe and stable recovery of the heat energy is realized, and the product quality and the purity are high, stable and reliable.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a method for large-scale production of high-purity phosphorus pentoxide using yellow phosphorus as a raw material. Background technique [0002] Phosphorus pentoxide is an important chemical raw material and a good dehydrating agent. It is an important raw material for the production of phosphoric acid, polyphosphoric acid, polyphosphate, triethyl phosphate, and fine phosphorus chemical products. [0003] At present, the main method of producing phosphorus pentoxide in the chemical industry is the method of oxidizing yellow phosphorus. The yellow phosphorus is fully burned in dry air to obtain a high-temperature mixed gas containing phosphorus pentoxide. [0004] The high-temperature mixed gas is quenched and cooled with the dry air in the tower body, and at the same time, it is cooled by natural heat exchange with the external air to obtain a solid phosphorus pentoxide...

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Problems solved by technology

The mixed gas is cooled with air in the tower body so that the concentration of phosphorus pentoxide in the mixed gas is greatly reduced. At the same time, due to the poor air drying effect and uneven distribution, the by-products of low oxide and metaphosphoric acid will reduce the quality of the product. In addition, It also exchanges heat naturally with the external air, and the poor heat exchange effect makes the tower wall in a high temperature state, which is easy to cause high temperature corrosion and shorten the service life of the device, and the production intensity of the device is greatly reduced, and the production capacity can only stay at 200-300t / a; at the same time, due to The traditional process is to use concentrated sulfuric acid as a desiccant in the empty air tower to dry the air, and the air is dried while the new impurity SO 3 into the air; solid yellow phosphorus is used to enter the combustion furnace and undergo combustion reaction with air. Due to the poor dispersion of solid yellow phosphorus in the gas phase, it is difficult to fully mix with air, and in addition, there is no secondary air supplement, resulting in incomplete combustion and low formation. Oxide P 2 o 3 Existence, resulting in lower product quality, low purity, can only reach 96%-98% fluctuation range

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