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Process for recycling clean waste liquid of polyvinyl chloride produced by calcium carbide method to caustic soda primary brine

A technology of polyvinyl chloride and calcium carbide method, which is used in water/sewage treatment, alkali metal hydroxide, chemical instruments and methods, etc., can solve the problem of not meeting environmental protection discharge requirements, total drainage chloride ions exceeding the standard, and no comprehensive utilization of water resources. and other problems, to achieve the effect of saving the amount of salt water, avoiding substandard, and reducing the efflux of waste liquid.

Active Publication Date: 2015-03-25
昊华宇航化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If this part of wastewater is discharged outside, it will cause the total drainage chlorine ion to exceed the standard, which cannot meet the environmental protection discharge requirements, and the water resources will not be comprehensively utilized.

Method used

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  • Process for recycling clean waste liquid of polyvinyl chloride produced by calcium carbide method to caustic soda primary brine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Such as figure 1 Shown, the technology that calcium carbide method polyvinyl chloride cleaning waste liquid is reused to caustic soda primary brine, it comprises the steps:

[0035] 1) In a 20L double-layer glass reactor, add 5L and let it sit for a period of time to take the clean waste liquid that has not been compounded but has been aerated in the calcium carbide method PVC acetylene cleaning section (the COD in the clean waste liquid after treatment is 125mg) / L), the content of available chlorine is almost zero after testing; add 50mL sodium hypochlorite solution, the content of available chlorine is 0.1% after testing, adjust the pH to 2 with hydrochloric acid, react for 10min, then adjust the pH to 12 with sodium hydroxide solution, Reaction 30min, filter precipitation; Described sodium hypochlorite solution is selected from the hyposodium that the tail chlorine absorption tower of caustic soda synthesis section produces, and the available chlorine content in hyp...

Embodiment 2

[0040] Such as figure 1 Shown, calcium carbide method polyvinyl chloride cleaning waste liquid reuse caustic soda primary brine process, it comprises the steps:

[0041]1) In a 20L double-layer glass reactor, add 5L of clean waste liquid taken from calcium carbide method polyvinyl chloride acetylene cleaning section with a compounding ratio of 50% and aeration treatment (COD in the clean waste liquid after treatment is 117mg / L ), the available chlorine content is 0.03% after testing; add 25mL sodium hypochlorite solution, the available chlorine content is 0.08% after testing, adjust the pH to 3 with hydrochloric acid, react for 20min, then adjust the pH to 12 with sodium hydroxide solution, react for 45min , filter precipitation; Described sodium hypochlorite solution is selected from the hyposodium that the tail chlorine absorption tower of caustic soda synthesis section produces, and the available chlorine content in hyposodium is 118g / L; Described hydrochloric acid is selec...

Embodiment 3

[0046] Such as figure 1 Shown, calcium carbide method polyvinyl chloride cleaning waste liquid reuse caustic soda primary brine process, it comprises the steps:

[0047] 1) In a 20L double-layer glass reactor, add 5L of clean waste liquid that is taken to the calcium carbide method polyvinyl chloride acetylene cleaning section to compound 80% and has been aerated (the COD in the clean waste liquid after treatment is 130mg / L) , wherein the available chlorine content is almost zero; add 40mL of sodium hypochlorite solution, wherein the available chlorine content is 0.08% after testing, adjust the pH value to 5 with hydrochloric acid, and react for 30 minutes; then adjust the pH to 12 with sodium hydroxide solution, react for 60 minutes, Filter the precipitate; the hydrochloric acid is selected from the hydrochloric acid in the hydrogen chloride synthesis section of caustic soda production, and the concentration is 30%; the sodium hydroxide solution is selected from the sodium hy...

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Abstract

The invention belongs to the technical field of chlor-alkali chemical industry, and discloses a process for recycling clean waste liquid of polyvinyl chloride produced by a calcium carbide method to caustic soda primary brine. The process comprises the following steps of: (1) removing acetylene gas contained in the clean waste liquid; (2) adding sodium hypochlorite to control available chlorine content to 0.06%-0.10%, adding hydrochloric acid to regulate a pH value to 2-5, and reacting for 10-30 minutes; (3) adding sodium hydroxide to regulate the pH value to be more than 12, reacting for 30-60 minutes, filtering, and depositing; (4) mixing filter liquor and the caustic soda primary brine, increasing temperature to 55-65 DEG C, adding sodium chloride, and controlling the content of sodium chloride to be more than 300 g / L; (5) adding sodium hydroxide to control the pH value to 10-12, adding ferric chloride hexahydrate, and reacting for more than 60 minutes, wherein the addition amount of ferric chloride hexahydrate is 0.08-0.12 g / L; (6) adding sodium carbonate, and reacting for more than 60 minutes, wherein the dose of sodium carbonate is controlled to be 0.3-0.8 g / L; (7) filtering, wherein the filter liquor is an intermediate product which reaches the effluent standard of primary brine. The process disclosed by the invention can be used for reducing the discharge of the waste liquid, preventing the high chloride content from causing that total effluent water can not reach the standard, reducing the content of calcium, magnesium and silicon, recycling a primary brine section and reducing the usage amount of brine.

Description

technical field [0001] The invention belongs to the technical field of chlor-alkali chemical industry, and in particular relates to a process for recycling polyvinyl chloride cleaning waste liquid by calcium carbide process into caustic soda primary brine. Background technique [0002] my country's energy structure is characterized by rich coal, poor oil, and little gas. Therefore, the domestic polyvinyl chloride (PVC) resin production process is mainly based on calcium carbide acetylene method. In 2013, the production capacity of PVC reached 24.76 million tons per year, of which the production capacity of calcium carbide PVC accounted for about 82% of the total production capacity. In the production process of calcium carbide acetylene method, during the purification process of crude acetylene gas, it is necessary to use sodium hypochlorite solution with a mass fraction of available chlorine in the range of 0.08-0.12% and a pH value of 7-8 to oxidize impurities such as...

Claims

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Application Information

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IPC IPC(8): C01D1/04
CPCC02F1/5236C02F1/66C02F9/00
Inventor 赵述彬荆智海杨三军闫凯峰魏成江贺基广胡移风张国辉崔二梅程涛程杏叶
Owner 昊华宇航化工有限责任公司