Stepped utilization method of steam in ammonium phosphate production

Abstract

The invention discloses a stepped utilization method of steam in ammonium phosphate production, which comprises the following steps: 1. three-time steam generated by two-stage concentration is introduced into a heat exchanger to heat and pre-concentrate raw material of thin phosphoric acid, and after heating, the steam at the terminal is discharged and condensed, the temperature of which is lowered; and 2. part reaction heat generated by neutralization of raw material of the phosphoric acid and ammonia is still used for secondarily concentrating ammonium phosphate slurry, and the other part of the steam continues to heat the raw material of the phosphoric acid by single-pass falling film evaporation so as to further pre-concentrate the phosphoric acid. The method has the advantages that: (1) by lowering the vaporization temperature at the terminal to 50DEG C-60DEG C, low-temperature pre-concentration of the phosphoric acid is realized, which saves the consumption of primary steam and reduces the emission of waste heat and gas; (2) auxiliary equipment runs steadily, forced circulation has high evaporation intensity, circulating power consumption is reduced, and the size of the equipment and pipelines is reduced; (3) the operation temperature is obviously reduced, and the corrosion and scaling on a heating surface caused by a concentrated medium are improved; and (4) the concentration operation expands towards a low-temperature area, thus improving the functions of the equipment.

Description

technical field [0001] The present invention relates to ammonium phosphate, and also relates to the thermal energy utilization of steam heating. Background technique [0002] As we all know, solid ammonium phosphate (hereinafter referred to as ammonium phosphate) mainly has two production processes: "phosphoric acid concentration method (traditional method)" and "neutralization slurry concentration method". [0003] Ammonium phosphate is a typical resource-intensive product. In addition to the consumption of phosphorus and sulfur mineral raw materials, a large amount of heat energy is consumed in processing processes such as evaporation, concentration and drying. All kinds of ammonium phosphate processes at home and abroad are "staged" dehydration processes relying on external energy supply, namely: ① low-pressure raw steam to concentrate dilute phosphoric acid, ② ammonium phosphate reaction heat to concentrate and neutralize the slurry, ③ ammonium phosphate slurry Hot air ...

AI Technical Summary

Problems solved by technology

In the existing neutralization slurry concentration process, raw steam is used for primary concentration of ammonium phosphate slurry, and secondary steam generated during concentration is used for secondary concentration of ammonium phosphate slurry. The final effect steam at ~90°C is discharged into the atmosphere, and its low-level heat source has not been converted and utilized, resulting in waste of energy

[0004] At present, there is no patent application for the utilization of steam in the production of ammonium phosphate

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