Equipment for recovering and utilizing heat energy generated by phosphor combustion and system for preparing phosphoric acid by hot method

Abstract

An equipment for recovering and utilizing the heat energy generated by burning yellow phosphorus and a system for preparing phosphoric acid by the hot method are disclosed. It is composed of steam manifold and burning tower with heat energy recovering function. The burning tower consists of ring-shaped membrane heat exchanger with fins, heat-insulaitng enclosed casing, P2O5 gas outlet tube, connecting tube of phosphorus sprayer, etc.. Its advantages include low consumption of coal, water and energy, low cost and reduced environmental pollution.

Description

technical field [0001] The invention belongs to the technical field of recovery and utilization of heat energy, in particular to the technical field of recovery and utilization of yellow phosphorus combustion heat energy in thermal phosphoric acid production. Background technique [0002] Phosphoric acid and its phosphates are important components of the chemical industry. The production of all phosphides and phosphates is inseparable from basic chemical raw materials - phosphorus and phosphoric acid. According to the production process of phosphoric acid, it can be divided into wet process phosphoric acid and thermal process phosphoric acid. The phosphoric acid produced by the decomposition of strong acid (such as sulfuric acid, nitric acid, hydrochloric acid, fluosilicic acid, etc.) and phosphate rock is called wet process phosphoric acid. Due to the low concentration of wet-process phosphoric acid (<40%) and many impurities, it is mainly used in the production of agr...

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Problems solved by technology

[0010] The main disadvantage of this patented technology is that if the temperature of the water wall is below the solidification temperature of phosphorus pentoxide, phosphorus pentoxide will solidify and adhere to the wall surface, which will affect the heat transfer of the water wall and reduce the combustion. The channel area of ​​the gas (especially near the convective tube bundle heat exchanger at the outlet)

[0019] The heat energy recovery process of this patent also has the following defects: ①According to the diagram and description of the patent, recovering waste heat can only turn pressurized water into superheated water or steam into superheated steam, but cannot turn low-temperature water into high-temperature High-pressure steam is not easy to use; ②The heat exchanger occupies the combustion space, which not only makes the equipment relatively large, but also increases equipment investment; ③The wall of the combustion tower is still cooled by cooling water, and the remaining heat recovery efficiency will not be too high (not described in the patent and heat recovery rate); ④Similar to the US patent, the use of controlled process conditions to produce a super phosphoric acid protective film can only slow down the corrosion of metal materials by high-temperature phosphorus vapor and its polymers in the production process, but cannot fundamentally prevent this corrosion

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