A system and method for recovering furfural from phenolic resin waste liquid

Abstract

The present application relates to the field of organic solvent recovery, and in particular to a system for recovering furfural from phenolic resin waste liquid and a recovery method thereof. A system for recovering furfural from phenolic resin waste liquid comprises: a deweighting component, wherein the deweighting component is provided with a first distillation tower, wherein the first distillation tower performs deweighting treatment on the phenolic resin waste liquid to remove phenol; a purification component, wherein the purification component is arranged on one side of the deweighting component and is connected to the deweighting component, wherein a second distillation tower is provided in the purification component to purify the components deweighted in the first distillation tower. The method comprises: S1, deweighting and stratification; S2, azeotropic distillation. The present application separates phenol that is prone to condensation reaction through double tower intermodal operation and then purifies furfural. The solid residue produced by condensation is reduced and the yield of distillation is improved. At the same time, the present application removes oxygen from furfural through negative pressure distillation of furfural, improves the color of furfural, and further improves its purity.

Description

Technical Field

[0001] The present application relates to the field of organic solvent recovery, and in particular to a system for recovering furfural from phenolic resin waste liquid and a recovery method thereof. Background Art

[0002] Furfural, also known as furan formaldehyde, is a colorless, transparent liquid with an almond-like smell. It is soluble in hot water, ethanol, ether and benzene, and gradually turns yellow to brown when oxidized in the air. Since it contains a furan ring and an aldehyde group, a large number of derivatives can be produced through oxidation, hydrogenation, condensation and other reactions. Furfural is an important organic chemical raw material obtained by hydrolysis of biomass and is a renewable, green chemical product. It is widely used in food, medicine, pesticides, chemicals and other fields, and can be synthesized to produce biodegradable polymer materials.

[0003] In view of the above-mentioned related technologies, the inventors found that there is a large amount of furfural in the phenolic resin waste liquid. If it is directly incinerated, it will cause a waste of resources. The high-temperature condensation reaction of ordinary single-tower distillation will cause a large amount of coking in the tower bottom to form phenolic resin, which greatly reduces the yield. In severe cases, it can cause the entire distillation tower bottom material to agglomerate. When phenol and furfural exist at the same time, there will be a condensation reaction, which will produce moisture and affect the quality of the finished product. At the same time, the contact between furfural and oxygen to form furfural acid coking will also affect the use of fillers and equipment. Summary of the invention

[0004] In order to improve the defect of poor effect of recovering furfural from phenolic resin waste liquid, the present application provides a system and a method for recovering furfural from phenolic resin waste liquid.

[0005] In a first aspect, the present application provides a system for recovering furfural from phenolic resin waste liquid, using the following technical solution:

[0006] A system for recovering furfural from phenolic resin waste liquid comprises:

[0007] A de-weighting component, wherein the de-weighting component is provided with a first distillation tower, wherein the first distillation tower performs a de-weighting treatment on the phenolic resin waste liquid to remove phenol;

[0008] A purification component is arranged at one side of the de-weighting component and is connected to the de-weighting component. A second distillation tower is arranged in the purification component to purify the components de-weighted in the first distillation tower.

[0009] By adopting the above technical scheme, the present application adopts a double distillation tower combined operation scheme, through the dual treatment of deweighting and purification, the phenol produced by the condensation reaction is first separated and then the furfural is refined, thereby reducing the solid residue produced by condensation and improving the yield and quality of distillation.

[0010] Preferably, the first distillation tower comprises:

[0011] A separator is arranged at one end of the tower top of the first distillation tower to collect and separate furfural and water in the distillation components of the first distillation tower.

[0012] By adopting the above technical scheme, the present application can effectively separate furfural and phenol through a layering device, thereby effectively improving the phenomenon that phenol is prone to condensation reaction during the furfural refining process, thereby improving the yield and quality of distillation.

[0013] In a second aspect, the present application provides a method for recovering furfural from phenolic resin waste liquid, comprising the following recovery steps:

[0014] S1, de-weighting and stratification: taking the waste liquid and placing it in a de-weighting component, and de-weighting it in a first distillation tower to remove phenol in the bottom of the tower. At the same time, the top components are stratified by a stratifier provided at one end of the top of the first distillation tower to collect the lower layer materials;

[0015] S2, azeotropic distillation: taking the lower layer material and passing it into the second distillation tower, taking out the furfural finished product through the furfural negative pressure azeotropic distillation side line of the second distillation tower, and the furfural can be recovered.

[0016] By adopting the above technical solution, the present application separates the phenol that is prone to condensation reaction through double tower combined operation and then purifies furfural. The solid residue produced by condensation is reduced and the distillation yield is improved. Furthermore, the present application removes oxygen from furfural through negative pressure distillation of furfural, improves the color of furfural, and further improves its purity.

[0017] Preferably, in step S1, the lower layer material comprises furfural and water, and the moisture content of the lower layer material is less than 10%.

[0018] Preferably, in step S1, the pressure of the first distillation tower for de-weighting treatment is 4.8-5.5 kPa, the top of the tower is 40-50° C., and the reflux ratio is 2.5-3.

[0019] Preferably, the operating pressure of the negative pressure azeotropic distillation in step S2 is 5-9 kPa, the top temperature is controlled at 65-68° C., and the reflux ratio of the distillation tower is controlled at 2-3.

[0020] By adopting the above technical scheme, the present application further optimizes the scheme for furfural purification, effectively optimizes the parameters for furfural purification, and improves the purity and quality of the furfural finally prepared.

[0021] In summary, this application has the following beneficial effects:

[0022] First, the present application uses double-tower combined operation to separate phenol that is prone to condensation reaction and then purify furfural, thereby reducing solid residues produced by condensation and improving the yield of distillation.

[0023] Second, the present application has achieved the standard of recycling and reuse through the heterogeneous azeotropic distillation dehydration of furfural itself, without the need for dehydration treatment through molecular sieves or pervaporation membranes. At the same time, since negative pressure distillation of furfural is used in the present application, oxygen in furfural is removed, and the finished furfural is colorless and does not change color within 7 days under nitrogen protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a system for recovering furfural from phenolic resin waste liquid in Example 1 of the present application.

[0025] Among them, 1. the first distillation tower; 11. the filter; 12. the classifier; 2. the second distillation tower. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the embodiments. Example

[0027] Example 1

[0028] S1, de-weighting and stratification: take the furfural waste liquid and place it in a filter for filtration treatment, collect the filtrate and place it in the first distillation tower, turn on the vacuum pump and heat it to 90 ° C, the top temperature is 40 ° C, the operating pressure is 4.8 kPa, the reflux ratio is 2.5, the azeotrope of furfural and water is extracted from the top of the first distillation tower, and the top components are stratified by a stratifier provided at one end of the top of the first distillation tower, and the lower layer material is collected;

[0029] S2, azeotropic distillation: take the lower layer material and pass it into the second distillation tower. When the liquid level in the bottom of the second distillation tower rises to two-thirds, turn on the vacuum pump to raise the temperature to 80-85°C in the bottom of the tower, the top temperature is 65°C, the operating pressure is 5kPa, and the reflux ratio is 2; continue to dehydrate the top of the tower through the second distillation tower furfural negative pressure azeotropic distillation, and produce the furfural finished product at a side line temperature of 70°C, so as to recover the furfural.

[0030] Example 2

[0031] S1, de-weighting and stratification: take the furfural waste liquid and place it in a filter for filtration treatment, collect the filtrate and place it in the first distillation tower, turn on the vacuum pump and heat it to 92 ° C, the top temperature is 45 ° C, the operating pressure is 5.2 kPa, the reflux ratio is 2.7, the azeotrope of furfural and water is extracted from the top of the first distillation tower, and the top components are stratified by a stratifier provided at one end of the top of the first distillation tower, and the lower layer material is collected;

[0032] S2, azeotropic distillation: take the lower layer material and pass it into the second distillation tower. When the liquid level in the bottom of the second distillation tower rises to two-thirds, turn on the vacuum pump to raise the temperature to 80-85°C in the bottom of the tower, 66°C at the top, 7kPa at the operating pressure, and 2.5 at the reflux ratio. Continue to dehydrate the top of the tower and conduct negative pressure azeotropic distillation of furfural in the second distillation tower. Take out the furfural product at a side line temperature of 71°C to recover the furfural.

[0033] It should be noted that the furfural treated by the layering device in the present application can enter the second distillation tower for refining, and can also enter the first distillation tower for reflux treatment.

[0034] Example 3

[0035] S1, de-weighting and stratification: take the furfural waste liquid and place it in a filter for filtration treatment, collect the filtrate and place it in the first distillation tower, turn on the vacuum pump and heat it to 95 ° C, the top temperature is 50 ° C, the operating pressure is 5.5 kPa, the reflux ratio is 3, the azeotrope of furfural and water is extracted from the top of the first distillation tower, and the top components are stratified by a stratifier provided at one end of the top of the first distillation tower, and the lower layer material is collected;

[0036] S2, azeotropic distillation: take the lower layer material and pass it into the second distillation tower. When the liquid level in the bottom of the second distillation tower rises to two-thirds, turn on the vacuum pump to raise the temperature to 85°C in the bottom, 68°C at the top, 9kPa at the operating pressure, and 3 at the reflux ratio; continue to dehydrate the top of the tower through negative pressure azeotropic distillation of furfural in the second distillation tower, and produce the furfural product at a side line temperature of 72°C to recover the furfural.

[0037] Comparative Example

[0038] Comparative Example 1

[0039] A method for recovering furfural from phenolic resin waste liquid. Compared with Example 1, the pressure of the first distillation tower in this comparative example is 10 kPa, the kettle temperature of the first distillation tower is 100°C, the azeotrope of furfural and water is azeotropically extracted from the tower top, the furfural product is collected when the top temperature is 76°C, and the furfural is collected by single-tower distillation.

[0040] Performance testing

[0041] The purity and moisture of furfural recovered in Examples 1 to 3 and Comparative Example 1 were tested, and the specific test results are shown in Table 1 below: Table 1 Performance Test Table

[0042]

[0043] Combining the data of Examples 1 to 3 and Comparative Example 1, it can be found that the technical solution of the present application separates the phenol that is prone to condensation reaction through double tower combined operation and then purifies furfural. The solid residue produced by condensation is reduced and the yield of distillation is improved. Furthermore, the present application removes oxygen from furfural through negative pressure distillation of furfural, improves the color of furfural, and further improves its purity.

[0044] Compared with Comparative Example 1, it can be further illustrated that after separating phenol in Examples 1 to 3 of the technical solution of the present application, the moisture content of furfural obtained is significantly lower than the moisture content of furfural in Comparative Example 1.

[0045] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A method for recovering furfural from phenolic resin waste liquid, characterized in that: The recycling steps include: S1, de-weighting and stratification: taking the waste liquid and placing it in a de-weighting component, and de-weighting it in a first distillation tower to remove phenol in the bottom of the tower. At the same time, the top components are stratified by a stratifier provided at one end of the top of the first distillation tower to collect the lower layer materials; S2, azeotropic distillation: taking the lower layer material and passing it into the second distillation tower, and taking out the furfural finished product through the furfural negative pressure azeotropic distillation side line of the second distillation tower, so as to recover the furfural; The furfural recovery system from the phenolic resin waste liquid comprises: A de-weighting component, wherein the de-weighting component is provided with a first distillation tower (1), wherein the first distillation tower (1) performs de-weighting treatment on the phenolic resin waste liquid to remove phenol; A purification component is arranged on one side of the de-weighting component and is connected to the de-weighting component. A second distillation tower (2) is arranged in the purification component to purify the components de-weighted in the first distillation tower (1).

2. The method for recovering furfural from phenolic resin waste liquid according to claim 1, characterized in that: The first distillation tower (1) comprises: A separator (12) is arranged at one end of the top of the first distillation tower (1) to collect and separate furfural and water in the distillation components of the first distillation tower (1).

3. The method for recovering furfural from phenolic resin waste liquid according to claim 1, characterized in that: In step S1, the lower layer material includes furfural and water, and the moisture content of the lower layer material is less than 10%.

4. The method for recovering furfural from phenolic resin waste liquid according to claim 1, characterized in that: In step S1, the pressure of the first distillation tower for de-weighting treatment is 4.8-5.5 kPa, the top of the tower is 40-50° C., and the reflux ratio is 2.5-3.

5. The method for recovering furfural from phenolic resin waste liquid according to claim 1, characterized in that: The operating pressure of the negative pressure azeotropic distillation in step S2 is 5-9 kPa, the top temperature is controlled at 65-68° C., and the reflux ratio of the distillation tower is controlled at 2-3.

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