Method for producing hexamethylene tetramin by formaldehyde-containing wastewater

Abstract

The invention relates to a method for producing urotropine by utilizing wastewater containing formaldehyde. Ammonia is added into the wastewater containing the formaldehyde, and the mixture is stirred to react for 3 to 15 hours to obtain a dilute solution of the urotropine under the condition that the pH value is controlled to be between 7 and 12 and the reaction temperature is between 10 and 90 DEG C; one or more devices of a filter press, a bag filter and a precision filter are adopted to remove solid components of the dilute solution of the urotropine, then an activated carbon filter is used to remove a viscous liquid of the dilute solution of the urotropine, then a microporous filter membrane with a pore diameter of between 0.2 and 1mu m is used to remove micron and submicron impurities and floccules in the solution, an ultrafiltration membrane is used to remove soluble macromolecular impurities, and the pollution index of the solution is less than or equal to 5; and the treated solution enters a first-order film for separation, a first-order thin solution is directly discharged or is used for industrial circulating water, a first-order thick solution is collected and stored in a tank when the mass fraction of the urotropine in the first-order thick solution is more than or equal to 6 percent, the first-order thick solution enters a second-order film for the separation, a second-order thin solution returns to the first-order film for the separation, and a second-order thick solution is collected and stored in the tank when the mass fraction of the urotropine in the second-order thick solution reaches more than 10 percent.

Description

technical field [0001] The invention relates to a method for producing urotropine by utilizing waste water containing formaldehyde, and belongs to the field of waste water recycling treatment method manufacturing. Background technique [0002] Formaldehyde is an important chemical raw material. It is widely used in pesticides, resins, and other fields. Many pesticides and chemical wastewater contain a large amount of formaldehyde. Pollution caused by formaldehyde wastewater must be strictly controlled. [0003] At present, the mass fraction of formaldehyde in formaldehyde-containing wastewater is generally below 5%, and it is difficult to recover by conventional methods. Generally, biochemical, catalytic oxidation, stripping and other methods are used for treatment. However, the above methods not only cannot recover valuable formaldehyde, but need to consume a large amount of Energy and resources, and formaldehyde in wastewater cannot be completely treated. [0004] CN1196...

AI Technical Summary

Problems solved by technology

[0003] At present, the mass fraction of formaldehyde in formaldehyde-containing wastewater is generally below 5%, and it is difficult to recover by conventional methods. Generally, biochemical, catalytic oxidation, stripping and other methods are used for treatment. However, the above methods not only cannot recover valuable formaldehyde, but need to consume a large amount of energy and resources, and formaldehyde in wastewater cannot be completely treated

[0004] CN1196339A, title " production method of quick-acting urine aldehyde nitrogen fertilizer ", it is to add urea in formaldehyde liquid, make the molar ratio of urea and formaldehyde be 2~5:1, heat and keep reaction temperature at 70~90 ℃, treat urea After completely dissolving and cooling, add acid solution to make the pH value between 3 and 4. After the reaction product is taken out and dried, the quick-acting urine aldehyde nitrogen fertilizer can be obtained, but only formaldehyde solution with a formaldehyde content of more than 9% can be used.

Its disadvantages: this method requires a variety of raw materials, and the processing process is cumbersome

Its disadvantages: not only require high content of waste formaldehyde, but also obtain urotropine by evaporation and concentration, which consumes a lot of energy

Its disadvantages: need steam heating, consume energy