Continuous production method of hydroxyethyl diphosphonic acid crystal

A technology of hydroxyethylene diphosphonic acid and its production method, which is applied in the field of continuous production of hydroxyethylene diphosphonic acid crystals, and can solve problems affecting product market application and promotion, unfavorable product quality stability, and limited product capacity scale and other issues, to achieve the effect of realizing automated large-scale production, realizing separation and purification, and shortening the production cycle

Active Publication Date: 2020-01-03
SHANDONG TAIHE WATER TREATMENT TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The existing disclosed methods for preparing hydroxyethylene diphosphonic acid solids or crystals all adopt traditional intermittent single-pot operation, which is unfavorable for the stability of product quality between batches; at the same time, because the...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The hydroxyethylidene diphosphonic acid liquid with an active content of 51.34% was preheated to 82°C with a graphite heater, separated from the gas and liquid to remove hydrogen chloride and a small amount of water vapor in the system, and then poured into the still at a constant speed of 250kg / h ; Feed continuously for 1 hour until the volume of the material accounts for about one-third of the volume of the kettle body, start the still to stir, maintain the temperature of the system at 125±1°C, and quickly evaporate and concentrate under negative pressure of -0.06MPa; continuously feed for 3 hours Finally, the active content of the material in the still is 70.28% and the volume of the material in the still reaches the set material transfer level, the valve at the bottom of the still and the material transfer pump are automatically opened, and the material cooled to 62°C is continuously transferred into the Crystallization is carried out in the first-stage crystalliza...

Embodiment 2

[0036]The hydroxyethylidene diphosphonic acid liquid with an active content of 60.29% was preheated to 90°C with a graphite heater, separated from the gas and liquid to remove hydrogen chloride and a small amount of water vapor in the system, and then poured into the still at a constant speed of 200kg / h ; Feed continuously for 1.5 hours until the volume of the material accounts for about one-third of the volume of the kettle body, start the still to stir, maintain the system temperature at 130±1°C, and quickly evaporate and concentrate under negative pressure of -0.04MPa; continuously feed for 4 hours Finally, the active content of the material in the still is 70.04% and the volume of the material in the still reaches the set material transfer level, the valve at the bottom of the still and the material transfer pump are automatically opened, and the material cooled to 65°C is continuously transferred into the Crystallization is carried out in the first-stage crystallization ...

Embodiment 3

[0038] The hydroxyethylidene diphosphonic acid liquid with an active content of 60.57% was preheated to 75°C with a graphite heater, separated from the gas and liquid to remove hydrogen chloride and a small amount of water vapor in the system, and then poured into the still at a constant speed of 300kg / h ;Continuously feed until the volume of the material accounts for about one-third of the volume of the kettle body, start the distillation kettle to stir, maintain the system temperature at 128±2°C, and quickly evaporate and concentrate under the negative pressure of -0.04MPa. After continuous feeding for 2.8 hours, The active content of the material in the still is 70.08% and the volume of the material in the still reaches the set material transfer level, the valve at the bottom of the still and the material transfer pump are automatically opened, and the material cooled to 70°C is continuously transferred to the first at a flow rate of 320kg / h. Stage crystallization kettle...

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PUM

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Abstract

The invention provides a continuous production method of a hydroxyethyl diphosphonic acid crystal. The specific operation method comprises the following steps: performing preheating and gas-liquid separation on a hydroxyethyl diphosphonic acid liquid product with active content being 50 to 65 percent, and throwing into a distilling kettle continuously at constant speed; when performing distillation and concentration until the material active content is more than or equal to 70 percent, completing step-by-step automatic material transfer on high-temperature materials among crystallization kettles which are connected in tail series after condensation, and performing step-by-step continuous crystallization under the conditions of stirring and naturally cooling; performing circular condensation and cooling in the n-stage crystallization kettle and maintaining the system temperature to 20+/-2 DEG C; and after performing crystallization completely, performing separation and drying treatmentto obtain a hydroxyethyl diphosphonic acid crystal product with the active content being more than or equal to 98 percent. The traditional single-kettle closed crystallization method is changed into aflow line crystallization method more suitable for industrialization, so the prepared crystallization granularity is proper, crystal aids and crystal nucleuses are not added in the crystallization process, explosive crystallization is avoided, and the continuous production method of the hydroxyethyl diphosphonic acid crystal is suitable for industrialization.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals production, and in particular relates to a continuous production method of hydroxyethylene diphosphonic acid crystals. Background technique [0002] Hydroxyethylidene diphosphonic acid (HEDP for short), because of its extremely stable C-P bond in its molecule, the bond energy is 246kJ / mol, it is resistant to high temperature, and has good scale inhibition effect on calcium carbonate, hydrated iron oxide and calcium phosphate in water , is an important scale inhibitor and dispersant. Because HEDP can form stable complexes with various metal ions such as iron, copper, and zinc, and can dissolve oxides on the metal surface, it can be used as a complexing agent in the cyanide-free electroplating industry; in addition, because HEDP has good corrosion inhibition Anti-scaling effect and passivation on metal surfaces, high-purity HEDP products can be used for cleaning and metal surface treatment o...

Claims

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Application Information

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IPC IPC(8): C07F9/38
CPCC07F9/3808
Inventor 程终发王燕平齐晓婧宋盟盟王宁宁刘全华
Owner SHANDONG TAIHE WATER TREATMENT TECH CO LTD
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