阅读说明：本技术 一种降低酚醛树脂废水中cod的方法和应用 (Method for reducing COD (chemical oxygen demand) in phenolic resin wastewater and application ) 是由 曾文龙 于 2020-06-16 设计创作，主要内容包括：本发明提供一种降低酚醛树脂废水中COD的方法和应用,涉及工业废水处理领域。本发明的方法包括以下步骤：S1、收集酚醛树脂生产制程中产生的废水,静置,分为上下两层,上层为低浓度废水,下层为高浓度废水,将低浓度废水和高浓度废水分离；S2、对高浓度废水进行检测,计算其中苯酚和甲醛的含量,通过添加甲醛调节高浓度废水的醛酚比F/P为0.6～0.9,加入酸触媒,进行聚合反应,得到酚醛树脂；S3、对低浓度废水进行检测,计算其中苯酚和甲醛的含量,通过添加甲醛调节低浓度废水醛酚比F/P为0.5～0.95,加入酸触媒,进行二次聚合反应,得到酚醛树脂。本发明的方法可有效降低酚醛树脂废水的COD值,回收废水中残留的原料,节约生产成本。(The invention provides a method for reducing COD in phenolic resin wastewater and application thereof, and relates to the field of industrial wastewater treatment. The method of the invention comprises the following steps: s1, collecting waste water generated in the production process of the phenolic resin, standing, dividing the waste water into an upper layer and a lower layer, wherein the upper layer is low-concentration waste water, and the lower layer is high-concentration waste water, and separating the low-concentration waste water from the high-concentration waste water; s2, detecting the high-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the high-concentration wastewater to be 0.6-0.9 by adding formaldehyde, adding an acid catalyst, and carrying out polymerization reaction to obtain phenolic resin; s3, detecting the low-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the low-concentration wastewater to be 0.5-0.95 by adding formaldehyde, adding an acid catalyst, and carrying out secondary polymerization reaction to obtain the phenolic resin. The method can effectively reduce the COD value of the phenolic resin wastewater, recover the residual raw materials in the wastewater and save the production cost.)

1. A method for reducing COD in phenolic resin wastewater is characterized by comprising the following steps:

s1, collecting waste water generated in the production process of the phenolic resin, standing, dividing the waste water into an upper layer and a lower layer, wherein the upper layer is low-concentration waste water, and the lower layer is high-concentration waste water, and separating the low-concentration waste water from the high-concentration waste water;

s2, detecting the high-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the high-concentration wastewater to be 0.6-0.9 by adding formaldehyde, adding an acid catalyst, and carrying out polymerization reaction to obtain phenolic resin;

s3, detecting the low-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the low-concentration wastewater to be 0.5-0.95 by adding formaldehyde, adding an acid catalyst, and carrying out secondary polymerization reaction to obtain the phenolic resin.

2. The method according to claim 1, wherein the COD value of the wastewater in the step S1 is 30-50 ten thousand mg/L.

3. The method as claimed in claim 1, wherein the acid catalyst in steps S2 and S3 is selected from: one or more of hydrochloric acid, sulfuric acid, oxalic acid and phosphoric acid.

4. The method as claimed in claim 1, wherein the formaldehyde in steps S2 and S3 is 37-44 vol.%.

5. The method as claimed in claim 1, wherein in step S2, the molar ratio of the acid catalyst to the phenol is 0.5-2: 100.

6. The method as claimed in claim 1, wherein in step S3, the mass ratio of the acid catalyst to the amount of the low-concentration wastewater is 0.1 to 1.5%.

7. The method according to claim 1, wherein the polymerization reaction in step S2 is specifically: and heating to 65-75 ℃, keeping the temperature for 0.5-1.5 h, continuously heating to 95-105 ℃, keeping the temperature for 3-5 h, performing vacuum dehydration, heating to raise the temperature to 165-175 ℃, and cooling to obtain the thermoplastic phenolic resin.

8. The method according to any one of claims 1 to 7, wherein the secondary polymerization reaction in the step S3 is specifically: heating to 65-75 ℃, keeping the temperature for 0.5-1.5 h, continuously heating to 95-105 ℃, keeping the temperature for 8-16 h, cooling after the reaction is finished, standing for 4-8 h, separating upper-layer wastewater from lower-layer liquid, wherein the lower-layer liquid is low-molecular-weight thermoplastic phenolic resin, detecting the COD value of the upper-layer wastewater, and transferring to the next-stage biochemical wastewater treatment.

9. The method as claimed in claim 8, wherein the low molecular weight thermoplastic phenolic resin is added with phenol and/or formaldehyde to adjust the F/P ratio to 0.6-0.9, acid catalyst is added, the temperature is raised to 65-75 ℃, the temperature is kept for 0.5-1.5 h, the temperature is continuously raised to 95-105 ℃, the temperature is kept for 3-5 h, vacuum dehydration is carried out, the temperature is raised to 165-175 ℃, and cooling is carried out, thus obtaining the thermoplastic phenolic resin.

10. Use of a process according to any one of claims 1 to 9 in the preparation of a phenolic novolac resin.

Technical Field

The invention relates to the field of industrial wastewater treatment, in particular to a method for reducing COD (chemical oxygen demand) in phenolic resin wastewater and application thereof.

Background

Industrial wastewater is inevitably generated in the production process of the phenolic resin, and the wastewater contains a large amount of harmful substances including residual formaldehyde, phenol and other raw materials, so that the COD value of the wastewater is high, and the wastewater can be discharged only after being treated and reaching the discharge standard. The existing phenolic aldehyde wastewater treatment method is complicated, and the recovery rate of effective components in the wastewater is low.

Disclosure of Invention

Therefore, in order to solve the above problems, it is necessary to provide a method for reducing the COD in the phenolic resin wastewater, which can effectively reduce the COD value of the phenolic resin wastewater, achieve the discharge standard, effectively recover the raw materials remaining in the wastewater, and save the production cost.

A method for reducing COD in phenolic resin wastewater comprises the following steps:

s1, collecting waste water generated in the production process of the phenolic resin, standing, dividing the waste water into an upper layer and a lower layer, wherein the upper layer is low-concentration waste water, and the lower layer is high-concentration waste water, and separating the low-concentration waste water from the high-concentration waste water;

s2, detecting the high-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the high-concentration wastewater to be 0.6-0.9 by adding formaldehyde, adding an acid catalyst, and carrying out polymerization reaction to obtain phenolic resin;

s3, detecting the low-concentration wastewater, calculating the content of phenol and formaldehyde, adjusting the formaldehyde-to-phenol ratio F/P of the low-concentration wastewater to be 0.5-0.95 by adding formaldehyde, adding an acid catalyst, and carrying out secondary polymerization reaction to obtain the phenolic resin.

According to the method, the residual phenol and formaldehyde in the phenolic resin wastewater can be fully recycled, the COD value of the phenolic resin wastewater is greatly reduced, the initial content of 30-50 ten thousand mg/L can be reduced to 4-5 ten thousand mg/L, and the treatment load of a rear-stage wastewater treatment field is greatly reduced; the waste water is divided into high-concentration waste water and low-concentration waste water, wherein the content of phenol and formaldehyde in the high-concentration waste water is higher, the high-concentration waste water can be directly used as a raw material for a production process of phenolic resin, the phenol and formaldehyde content in the low-concentration waste water is lower, the phenolic resin can be obtained by adding reactants to carry out secondary polymerization, and the COD value of the treated waste water is reduced by about 75-85%. The effective components in the wastewater can be recycled, and meanwhile, the phenolic resin material meeting the industrial requirements can be produced, and the phenolic resin material can be applied to products such as phenolic resin molding materials, phenolic resin adhesives, phenolic resin impregnated materials and the like.

In one embodiment, the COD value of the wastewater in the step S1 is 30-50 ten thousand mg/L.

In one embodiment, the acid catalyst in steps S2 and S3 is selected from: one or more of hydrochloric acid, sulfuric acid, oxalic acid and phosphoric acid.

In one embodiment, the COD value of the wastewater in the step S1 is 30-50 ten thousand mg/L.

In one embodiment, the formaldehyde in steps S2 and S3 is 37-44 vol%.

In one embodiment, in step S2, the molar ratio of the acid catalyst to the phenol is 0.5-2: 100.

In one embodiment, in step S3, the mass ratio of the acid catalyst to the low-concentration wastewater is 0.1% to 1.5%.

In one embodiment, the polymerization reaction in step S2 is specifically: and heating to 65-75 ℃, keeping the temperature for 0.5-1.5 h, continuously heating to 95-105 ℃, keeping the temperature for 3-5 h, performing vacuum dehydration, heating to raise the temperature to 165-175 ℃, and cooling to obtain the thermoplastic phenolic resin.

In one embodiment, the secondary polymerization in step S3 is specifically: heating to 65-75 ℃, keeping the temperature for 0.5-1.5 h, continuously heating to 95-105 ℃, keeping the temperature for 8-16 h, cooling after the reaction is finished, standing for 4-8 h, separating upper-layer wastewater from lower-layer liquid, wherein the lower-layer liquid is low-molecular-weight thermoplastic phenolic resin, detecting the COD value of the upper-layer wastewater, and transferring to the next-stage biochemical wastewater treatment. Because phenol and formaldehyde in the low-concentration wastewater have reacted to generate low-molecular-weight thermoplastic phenolic resin, the upper-layer wastewater obtained after the reaction contains extremely low phenol and formaldehyde, and the COD value of the wastewater is remarkably reduced.

In one embodiment, phenol and/or formaldehyde is added into the low molecular weight thermoplastic phenolic resin to adjust the ratio F/P of the aldehyde to the phenol to be 0.6-0.9, an acid catalyst is added, the temperature is increased to 65-75 ℃, the temperature is kept for 0.5-1.5 h, the temperature is continuously increased to 95-105 ℃, the temperature is kept for 3-5 h, vacuum dehydration is carried out, the temperature is heated to 165-175 ℃, and cooling is carried out, so that the thermoplastic phenolic resin is obtained.

The invention also provides application of the method in preparing the thermoplastic phenolic resin. The waste water is utilized to prepare the phenolic resin, and the obtained phenolic resin meets the industrial requirements, so that the production cost is saved, and the environment is protected.

Compared with the prior art, the invention has the following beneficial effects:

the method can fully recycle the residual phenol and formaldehyde in the phenolic resin wastewater, greatly reduce the COD value of the phenolic resin wastewater from the initial 30-50 ten thousand mg/L to 4-5 ten thousand mg/L, and greatly reduce the treatment load of a rear-stage wastewater treatment field; the waste water is divided into high-concentration waste water and low-concentration waste water, wherein the content of phenol and formaldehyde in the high-concentration waste water is higher, the high-concentration waste water can be directly used as a raw material for a production process of phenolic resin, the phenol and formaldehyde content in the low-concentration waste water is lower, the phenolic resin can be obtained by adding reactants to carry out secondary polymerization, and the COD value of the treated waste water is reduced by about 75-85%. The effective components in the wastewater can be recycled, and meanwhile, the phenolic resin material meeting the industrial requirements can be produced, and the phenolic resin material can be applied to products such as phenolic resin molding materials, phenolic resin adhesives or phenolic resin impregnated materials.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the preferred embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In the following examples and comparative examples F/P means the molar ratio of formaldehyde to phenol.