Method for producing phosphoric acid by adopting steam heating forced circulation concentration wet process and its equipment

A forced-circulation, wet-process phosphoric acid technology, applied in chemical instruments and methods, phosphorus compounds, halide silicon compounds, etc., can solve the problems of high operation and maintenance costs, low fluorine washing efficiency, large steam consumption, etc. The effect of low cost, high fluorine washing efficiency and less process equipment

Inactive Publication Date: 2003-12-10
EAST CHINA ENG SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The traditional process has complex equipment, high operation and maintenance costs, and P in the concen...

Method used

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  • Method for producing phosphoric acid by adopting steam heating forced circulation concentration wet process and its equipment
  • Method for producing phosphoric acid by adopting steam heating forced circulation concentration wet process and its equipment

Examples

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example 1

[0025] Adopt the 60,000 tons / year P of the present invention 2 o 5 Phosphoric acid concentrator

[0026] See attached picture. The equipment for concentrated wet-process phosphoric acid by steam heating and forced circulation includes a circulation loop formed by a flash evaporator 1, a graphite heat exchanger 2 and an axial circulation pump 3. The fluorine absorption tower has first and second fluorine absorption towers 6 and 7, Spray circulation pumps 8 and 9 are installed outside the fluorine absorption towers 6 and 7 respectively. The second fluorine absorption tower 7 communicates with the atmospheric condenser 10 , and the atmospheric condenser 10 communicates with the condensate liquid seal tank 11 .

[0027] 25% P pumped by dilute phosphoric acid 2 o 5 Filter the acid, and add it to the heat exchange area of ​​315m after metering 2 The outlet pipe of the graphite heat exchanger 2 enters the bottom of the flash evaporator 1 together with the heated circulating aci...

example 2

[0030] Adopt 80,000 tons / year P of the present invention 2 o 5 Phosphoric acid concentrator

[0031] See attached picture. 25% P pumped by dilute phosphoric acid 2 o 5 Filter the acid, and add it to the heat exchange area of ​​430m after metering 2 The outlet pipe of the shell and tube graphite heat exchanger enters the flash evaporator together with the heated circulating acid for vacuum concentration. The diameter of the flash chamber is φ5800mm, the height is 8358mm, and the effective volume is 160m 3 , after continuous cycle evaporation, dilute phosphoric acid is continuously concentrated, reaching 48%-50% P 2 o 5 , pumped out from the flash evaporator by the concentrated phosphoric acid pump, and sent to the phosphoric acid tank area. Containing HF, SiF escaped from the flasher 4 , water vapor and a small amount of phosphoric acid mist and other gases, the acid mist entrained in the gas is separated by the demister, and enters the fluorine absorption tower for was...

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Abstract

The phosphoric acid can be circularly heated and concentrated in a circulating loop formed from flash chamber, graphitic heat exchanger and axial-flow circulating pump, the diluted phosphoric acid can be added into the circulating loop from outlet pipe of graphitic heat exchanger, and the evaporated steam can be passed through the entrainment eliminator to remove entrained acid foam, then the steam is more passed through two-stage fluorine absorbing tower, sprayed and washed so as to recover fluoride in the gas phase. The vacuum required for flash chamber is provided by atmosphere condenser. Said invention can make wet phosphoric acid be concentrated to 48-50% P2O5 from 20-25% P2O5.

Description

technical field [0001] The invention relates to a phosphoric acid production process, more specifically a wet-process phosphoric acid concentration technology and its equipment. Background technique [0002] There are two methods for phosphoric acid concentration, direct heat transfer and indirect heat transfer. In order to avoid fouling of impurities dissolved in dilute acid on the heat transfer surface, the early wet-process phosphoric acid concentration mostly used direct heat transfer. Due to the increase in fuel costs and the emergence of new manufacturing materials, operational experience and engineering experience in slowing down scaling have been accumulated, and the concentrated method of indirect heat transfer has gradually replaced the method of direct heat transfer. At present, the most widely used indirect heat transfer concentration process is a vacuum evaporation process with low-pressure steam as the heat source and forced circulation. [0003] In phosphori...

Claims

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Application Information

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IPC IPC(8): C01B25/234C01B25/237C01B33/10
Inventor 洪金武崔琳琳喻军胡文生吴大农徐新源
Owner EAST CHINA ENG SCI & TECH
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