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A pickling waste liquor regeneration system and method for removing free acid in advance

A technology for pickling waste liquid and free acid, applied in combustion methods, chemical instruments and methods, combustion types, etc., can solve the problems of large investment and large land occupation, and achieve reduction of natural gas consumption, operation cost and process energy consumption The effect of reducing and improving the waste liquid treatment capacity

Active Publication Date: 2021-03-02
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, with the continuous enlargement of pickling scale in the iron and steel industry, the acid regeneration devices of many enterprises have been overloaded and cannot meet the requirements of enterprises. They are all considering the expansion of acid regeneration
However, the acid regeneration device involves the construction of a hydrolysis calcination furnace, which requires a large investment and occupies a large area. Most enterprises are eager to carry out transformation on the original device, expand production capacity and reduce equipment transformation costs under the premise of ensuring acid regeneration efficiency.

Method used

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  • A pickling waste liquor regeneration system and method for removing free acid in advance
  • A pickling waste liquor regeneration system and method for removing free acid in advance
  • A pickling waste liquor regeneration system and method for removing free acid in advance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] A method for regenerating pickling waste liquor that removes free acid in advance, said method comprising:

[0076] (1) The pickling waste liquid is contacted with high-temperature flue gas and pre-concentrated at 95°C. The composition of the pickling waste liquid is:

[0077] Element g / L kg / h Remark FeCl 3

38.3 122.57 Fe 3+ =13.2g / L

FeCl 2

272.36 872.56 Fe 2+ =120.0g / L

HCl 43.4 138.88 h 2 o

927.84 2969.1 total 1243.60 3979.54

[0078] The volume of waste liquid treated per hour is 3.2m 3 ;

[0079] The pickling waste liquid after pre-concentration is composed of:

[0080] Element g / L kg / h Remark FeCl 3

51.11 122.68 Fe 3+ =17.6g / L

FeCl 2

363.15 871.56 Fe 2+ =160g / L

HCl 101.01 244.83 h 2 o

862.96 2071.11 total 1379.24 3310.18

[0081] (2) Preheat the pre-concentrated pickling waste liquid to 115°C at ...

Embodiment 2

[0090] A method for regenerating pickling waste liquor that removes free acid in advance, said method comprising:

[0091] (1) The pickling waste liquid is contacted with high-temperature flue gas and pre-concentrated at 90°C. The composition of the pickling waste liquid is:

[0092] Element g / L kg / h Remark FeCl 3

32.5 104.0 Fe 3+ =11.2g / L

FeCl 2

294.82 943.43 Fe 2+ =130.0g / L

HCl 35.7 114.24 h 2 o

930.10 2976.7 total 1293.2 4138.37

[0093] Waste liquid treatment per hour: 3.2m 3 ;

[0094] The pickling waste liquid after pre-concentration is composed of:

[0095]

[0096]

[0097] (2) Preheat the pre-concentrated pickling waste liquid to 113°C at 0.4MPa, and then perform negative pressure flash evaporation at -0.09MPa. The gas phase after flash evaporation is condensed at 30°C to obtain a mass fraction of 20.3%. Hydrochloric acid solution, the mass flow rate of hydrochloric acid solu...

Embodiment 3

[0107] A method for regenerating pickling waste liquor that removes free acid in advance, said method comprising:

[0108] (1) The pickling waste liquid is contacted with high-temperature flue gas and pre-concentrated at 92°C. The composition of the pickling waste liquid is:

[0109]

[0110]

[0111] Waste liquid treatment per hour: 3.2m 3 ;

[0112] The pickling waste liquid after pre-concentration is composed of:

[0113] Element g / L kg / h Remark FeCl 3

51.11 122.57 Fe 3+ =14.74g / L

FeCl 2

453.57 1088.57 Fe 2+ =173.3g / L

HCl 99.46 238.7 h 2 o

786 1886.4 total 1390.14 3336.24

[0114] (2) Preheat the pre-concentrated pickling waste liquid to 116°C at 0.6MPa, and then perform negative pressure flash evaporation at -0.095MPa. The gas phase after flash evaporation is condensed at 33°C to obtain a mass fraction of 23.5%. Hydrochloric acid solution, the mass fraction of hydrochloric acid so...

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Abstract

The invention provides an acid pickling waste liquor regeneration method for removing free acid in advance. The method comprises the following steps: acid pickling waste liquor and high temperature flue gas are contacted for preconcentration; the pre-concentrated acid pickling waste liquor is preheated, vacuum flash evaporation is then carried out, and a gaseous phase obtained after the vacuum flash evaporation is condensed to obtain a hydrochloric acid solution; a liquid phase obtained after the vacuum flash evaporation is sent into a hydrolysis calcining device for pyrolysis to obtain high-temperature flue gas, and the high-temperature flue gas undergoes dust removal treatment; and the dust-removed high-temperature flue gas returns for preconcentration of the acid pickling waste liquor.By operations such as preheating, vacuum flash evaporation, condensation and the like of free hydrochloric acid in the acid pickling waste liquor after the condensation, early removal of the free acidin the acid pickling waste liquor is realized, waste liquor treatment capacity of existing devices is greatly improved, and energy consumption of the hydrolysis calcining device and consumption of natural gas are reduced.

Description

technical field [0001] The invention belongs to the field of pickling waste liquid treatment, and relates to a pickling waste liquid regeneration system and method, in particular to a pickling waste liquid regeneration system and method for removing free acid in advance. Background technique [0002] During the deep processing of steel, the surface needs to be pickled and derusted. The commonly used pickling solution is a hydrochloric acid solution with a mass fraction of 18-25%. During the pickling process of steel, the acid reacts with iron and iron oxides to produce ferrous salts. With the increase in the amount of pickling steel, the concentration of iron salts in the pickling solution continues to increase, while the concentration of acid is getting lower and lower. The content varies with the pickling process, operating temperature, steel species and specifications, and generally contains chloride 10-20% of ferrous iron, 3-10% of hydrogen chloride, so acid regeneratio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/06C02F1/10C02F1/16F23G7/00
CPCC02F1/06C02F1/10C02F1/16F23G7/008
Inventor 杨刚王云山安学斌
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI