CN103755087B - The System and method for of a kind of aromatization of methanol processing wastewater process - Google Patents

Abstract

A methanol aromatization process wastewater treatment system, including a high-temperature stripping device for removing most of the organic matter in the waste water, a carbon media absorption device for removing organic acids and part of the organic matter in the waste water from the high-temperature stripping device, and a An anion exchange system for reducing the organic acid in the waste water of the carbon-extracting medium absorption unit to a trace amount. During treatment, the waste water from the methanol aromatization process first enters the high-temperature stripping unit, where a large amount of organic matter and a small amount of organic acid are removed; then Absorb and further remove organic matter and organic acid in the carbon medium absorption device, and finally the waste water enters the anion exchange system to remove the organic acid, so that the concentration of the organic acid in the discharged waste water is less than 20ppm, and the present invention does not use lye to neutralize the salt in the waste water content, reduce the difficulty of subsequent treatment and utilization; can greatly shorten the process of wastewater treatment, reduce investment in wastewater treatment, while low energy consumption, easy regeneration of carbon media, long life, low operating costs.

Description

A system and method for methanol aromatization process wastewater treatment

technical field

The invention belongs to the technical field of waste water treatment, and in particular relates to a system and method for treating waste water in a methanol aromatization process.

Background technique

Aromatics is an important basic raw material in the modern chemical industry. Traditionally, aromatics mainly come from petroleum processing, and its raw material is mainly naphtha. In recent years, the process of producing aromatics from oxygenates, especially the process of producing aromatics from methanol\dimethyl ether has become increasingly popular. It is mature and is expected to complete industrial application in recent years.

At present, no reports on the system and process of methanol aromatization process wastewater treatment and reuse process have been considered. Compared with the current wastewater treatment process, the wastewater treatment of methanol to aromatics process has its own characteristics:

1. There are certain petroleum substances and alcohol substances in the wastewater, and the content of organic matter is relatively high.

2. Wastewater contains certain acidic organic matter.

3. The content of ammonia nitrogen and phenols in wastewater is low.

At present, a large amount of oily sewage containing organic acids is produced during the reaction process of petrochemical and coal chemical industry. The treatment method generally adopts conventional treatment methods. The alkali neutralizes the organic acids in the wastewater, and then further achieves the reuse effect of the wastewater through biological treatment and advanced treatment. During the neutralization process, a large amount of salt substances will be generated in the wastewater, which will affect the application of the wastewater in the system. , At the same time, it will also inhibit the microorganisms in the biological treatment process in the wastewater treatment process, which will bring difficulties to the subsequent treatment and comprehensive treatment. Generally speaking, this treatment method has a long process, large investment, high operating cost of wastewater treatment unit, and unstable operation.

Contents of the invention

The present invention provides a system and method for the treatment of methanol aromatization process wastewater, which overcomes the difficulties in the subsequent treatment and comprehensive treatment caused by the neutralization process used to produce a large amount of salt substances in the organic wastewater treatment process of organic acids And the existing treatment method has the disadvantages of long process flow, large investment, high operating cost of wastewater treatment unit, and unstable operation.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A system for the treatment of methanol aromatization process wastewater, comprising:

A high-temperature stripping unit 1 for removing most of the organic matter in the wastewater;

Connected to the high-temperature stripping device 1, a carbon media absorption device 2 for removing organic acids and some organic matter in the waste water of the high-temperature stripping device 1;

And connected to the carbon media absorption device 2, an anion exchange system 3 for reducing the organic acid in the waste water of the carbon media absorption device 2 to a trace amount.

The high-temperature stripping device 1 is composed of one or two stripping towers.

The carbon media absorption device 2 is composed of one or more carbon media absorption layers, and the carbon media is one or more of carbon nanotubes, graphene, expanded graphite, carbon fibers and activated carbon.

The anion exchange system 3 consists of two parallel fixed beds filled with anion exchange resin.

The present invention also provides a wastewater treatment method based on the methanol aromatization wastewater treatment system described in claim 1, comprising the following steps:

a) Waste water from methanol aromatization process first enters the high-temperature stripping device 1, the temperature at the bottom of the high-temperature stripping device 1 is 100-120°C, in which a large amount of organic matter and a small amount of organic acid are removed, and the COD (Cr) is less than 600, The concentration of organic acid is less than 200ppm;

b) The waste water from the high-temperature stripping unit 1 enters the carbon media absorption unit 2 to absorb and remove organic matter and a part of organic acids in the waste water. The COD (Cr) of the waste water at the outlet is less than 200, and the concentration of organic acids is less than 60 ppm;

c) The waste water from the carbon medium absorption device 2 enters the anion exchange system 3 to remove the organic acid in the waste water, so that the concentration of the organic acid in the discharged waste water is less than 20ppm.

Described anion exchange removes the organic acid in waste water, comprises the steps:

a) The waste water from the carbon medium absorption device 2 passes through the weakly basic anion exchange system 3, and part of the organic acid is absorbed, and the organic acid content in the effluent of the anion exchange system 3 is less than 10 ppm;

b) The organic acid content in the effluent of anion exchange system 3 is greater than 20ppm, the resin adsorption is close to saturation, stop the adsorption, and blow out the liquid in the system with air;

c) Into the saturated ion exchange system 3, 5-10wt% weak alkali solution is introduced for desorption;

d) The ion exchange system 3 after desorption uses air to blow out the lye.

Described lye comprises ammonia water, sodium hydroxide, calcium hydroxide.

The carbon media absorption device 2 absorbs and removes organic matter and organic acids in waste water, comprising the following steps:

a) The waste water from the high-temperature stripping unit 1 absorbs organic matter and organic acids in the waste water through the carbon media absorption unit 2 equipped with carbon materials, the COD of the effluent is less than 200ppm, and the organic acid content is less than 50ppm;

b) The COD of the effluent in the carbon medium absorption device 2 is close to 200ppm, the organic acid is close to 60ppm, the carbon material is close to saturation, stop the adsorption, and use air to blow out the liquid of the device;

c) Using high-temperature water vapor to remove the organic matter and organic acid adsorbed on the surface of the carbon medium, and further recycling.

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

(1) Neutralization without lye can reduce the salt content in wastewater and reduce the difficulty of subsequent treatment and utilization;

(2) This method can greatly shorten the wastewater treatment process and reduce the investment in wastewater treatment.

(3) The method has low energy consumption for wastewater treatment, easy regeneration of carbon medium, long service life and low operation cost.

Description of drawings

Figure 1 is a process flow diagram of an embodiment of the present invention.

Detailed ways

The implementation of the present invention will be described in detail below in conjunction with the drawings and examples.

As shown in Figure 1, a system for the treatment of methanol aromatization wastewater of the present invention includes a high-temperature stripping device 1 for removing most of the organic matter in the wastewater, a high-temperature stripping device 1 for removing organic acids and A carbon media absorption device 2 for some organic matter, and an anion exchange system 3 for reducing organic acids in the waste water of the carbon media absorption device 2 to trace amounts. Wherein the high-temperature stripping unit 1 can be made up of one or two stripping towers; The carbon medium absorption unit 2 can be made up of one or more carbon medium absorption layers, and the carbon medium can be carbon nanotube, graphene, expanded graphite, carbon fiber and One or several types of activated carbon; the anion exchange system 3 can be composed of two parallel fixed beds filled with anion exchange resins.

According to the method of wastewater treatment in this system, most of the organic matter is firstly removed by steam stripping, then most of the hydrocarbons and organic acids are removed by carbon media (carbon nanotubes, carbon fibers or activated carbon) absorption, and finally the acids are completely removed by ion exchange , so that the concentration of organic acid in the final external drainage is reduced to below 20ppm, and the COD (Cr) is reduced to below 200ppm.

The treatment method of the methanol aromatization process waste water that the present invention adopts comprises the following steps:

a) Sewage Wastewater from methanol aromatization process first enters high-temperature stripping device 1, the temperature at the bottom of the device is 100-120oC, and a large amount of organic matter and a small amount of organic acid are removed. The COD (Cr) is less than 600, and the concentration of organic acid is less than 200ppm.

b) The wastewater from the high-temperature stripping unit 1 enters the carbon media absorption unit 2 to absorb and remove organic matter and organic acids in the wastewater. The COD (Cr) of the outlet wastewater is less than 200, and the concentration of organic acids is less than 60ppm.

c) The waste water from the carbon media absorption device 2 enters the anion exchange system 3 to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the outgoing waste water is less than 20ppm.

Use anion exchange to remove organic acids in wastewater, including the following steps:

a) The waste water from the carbon medium absorption device 2 passes through the weakly basic anion exchange system 3, and the organic acid is adsorbed, and the organic acid content in the effluent of the anion exchange system 3 is less than 10 ppm.

b) The organic acid content in the effluent of anion exchange system 3 is greater than 20ppm, the resin adsorption is close to saturation, stop the adsorption, and blow out the liquid in the system with air.

c) Passing 5-10wt% weak alkali solution into the saturated ion exchange system 3 for desorption.

d) The ion exchange system 3 after desorption uses air to blow out the lye.

Using carbon media absorption device 2 to absorb and remove organic matter and organic acids in waste water includes the following steps:

a) The waste water from the high-temperature stripping unit 1 absorbs organic matter and organic acids in the waste water through the carbon media absorption unit 2 equipped with carbon materials. The COD of the effluent is less than 160ppm, and the organic acid content is less than 50ppm.

b) The COD of the effluent in the carbon media absorption device 2 is close to 200ppm, the organic acid is close to 60ppm, the carbon material is close to saturation, stop the adsorption, and use air to blow out the liquid in the device.

c) Using high-temperature water vapor to remove the organic matter and organic acid adsorbed on the surface of the carbon medium, and further recycling.

The technical solution of the present description will be further described below in conjunction with FIG. 1 .

Example 1

Wastewater from the methanol aromatization system first enters a single high-temperature stripper. The temperature at the bottom of the stripper is 120oC to remove a large amount of organic matter and a small amount of organic acid. The COD (Cr) of the effluent is 500 and the concentration of organic acid is 200ppm.

The wastewater from the stripping tower enters the carbon media absorption device 2 composed of two first-level parallel absorption towers, in which the carbon media is carbon nanotubes, and the absorption tower is composed of 10 layers of carbon nanotube absorption layers, and carbon nanotubes are used to absorb and remove wastewater The organic matter and organic acid in the wastewater, the COD (Cr) of the outlet wastewater is 160, and the concentration of organic acid is 50ppm. When the COD concentration in the outlet wastewater of the carbon media absorption device is higher than 200ppm or the concentration of organic acid is higher than 60ppm, the absorption tower is switched, and then the carbon material in the absorption tower is regenerated, and the high-temperature water vapor is introduced from the water vapor inlet to remove the adsorption. The organic matters and organic acids on the surface of the carbon media are further recycled.

The waste water from the carbon medium absorption unit 2 enters the anion exchange system 3 with two parallel anion exchange resins as filler fixed beds to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the discharged waste water is 10 ppm. When the concentration of organic acid in the discharged waste water is 20ppm, after the anion exchange resin is gradually adsorbed and saturated, the parallel fixed bed is switched, and 10% ammonia water is used for regeneration, and the regeneration liquid is discharged. When the outlet concentration of ammonia water reaches 95% of the inlet concentration % or more, it indicates that the resin has been fully regenerated, stop the regeneration, use air to blow off the lye in the system, complete the regeneration work, and can be further switched to use.

Example 2

Wastewater from the methanol aromatization system first enters a single high-temperature stripper. The temperature at the bottom of the stripper is 100oC to remove a large amount of organic matter and a small amount of organic acid. The COD (Cr) of the effluent is 600 and the concentration of organic acid is 200ppm.

The waste water from the stripping tower enters the carbon media absorption device 2 composed of two parallel absorption towers, wherein the carbon media is graphene, and the absorption tower is composed of 10 layers of graphene absorption layers, and uses graphene to absorb and remove organic matter and organic matter in the waste water. acid, the COD (Cr) of its outlet wastewater is 140, and the concentration of organic acid is 40ppm. When the COD concentration in the outlet wastewater of the carbon media absorption device is higher than 200ppm or the concentration of organic acid is higher than 60ppm, the absorption tower is switched, and then the carbon material in the absorption tower is regenerated, and the high-temperature water vapor is introduced from the water vapor inlet to remove the adsorption. The organic matters and organic acids on the surface of the carbon media are further recycled.

The waste water from the carbon medium absorption unit 2 enters the anion exchange system 3 with two parallel anion exchange resins as filler fixed beds to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the discharged waste water is 10 ppm. When the concentration of organic acid in the discharged waste water is 20ppm, after the anion exchange resin is gradually adsorbed and saturated, the parallel fixed bed is switched, and 5% sodium hydroxide is used for regeneration, and the regeneration liquid is discharged. When the outlet concentration of sodium hydroxide reaches When the inlet concentration is above 95%, it indicates that the resin has been completely regenerated, stop the regeneration, use air to blow off the lye in the system, complete the regeneration work, and can be further switched to use.

Example 3

Wastewater from the methanol aromatization system first enters a single high-temperature stripper. The temperature at the bottom of the stripper is 110oC to remove a large amount of organic matter and a small amount of organic acid. The COD (Cr) of the effluent is 600 and the concentration of organic acid is 200ppm.

The waste water from the stripping tower enters the carbon medium absorption device 2 composed of two parallel absorption towers, wherein the carbon medium is expanded graphite, and the absorption tower is composed of 5 layers of expanded graphite absorption layers, and utilizes expanded graphite to absorb and remove organic matter and Organic acid, the COD (Cr) of the outlet wastewater is 130, and the concentration of organic acid is 45ppm. When the COD concentration in the outlet wastewater of the carbon media absorption device is higher than 200ppm or the concentration of organic acid is higher than 60ppm, the absorption tower is switched, and then the carbon material in the absorption tower is regenerated, and the high-temperature water vapor is introduced from the water vapor inlet to remove the adsorption. The organic matters and organic acids on the surface of the carbon media are further recycled.

The waste water from the carbon medium absorption unit 2 enters the anion exchange system 3 with two parallel anion exchange resins as filler fixed beds to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the discharged waste water is 8ppm. When the concentration of organic acid in the discharged waste water is 20ppm, after the anion exchange resin is gradually adsorbed and saturated, the parallel fixed bed is switched, and 5% calcium hydroxide is used for regeneration, and the regeneration liquid is discharged. When the outlet concentration of calcium hydroxide reaches When the inlet concentration is above 95%, it indicates that the resin has been completely regenerated, stop the regeneration, use air to blow off the lye in the system, complete the regeneration work, and can be further switched to use.

Example 4

Wastewater from the methanol aromatization system first enters a single high-temperature stripper. The temperature at the bottom of the stripper is 120oC to remove a large amount of organic matter and a small amount of organic acid. The COD (Cr) of the effluent is 500 and the concentration of organic acid is 150ppm.

The waste water from the stripping tower enters the carbon medium absorption device 2 composed of two parallel absorption towers, wherein the carbon medium is carbon fiber, and the absorption tower is composed of 20 layers of carbon fiber absorption layers, and the organic matter and organic acid in the waste water are removed by carbon fiber absorption. The COD (Cr) of its outlet wastewater is 120, and the organic acid concentration is 40ppm. When the COD concentration in the outlet wastewater of the carbon media absorption device is higher than 200ppm or the concentration of organic acid is higher than 60ppm, the absorption tower is switched, and then the carbon material in the absorption tower is regenerated, and the high-temperature water vapor is introduced from the water vapor inlet to remove the adsorption. The organic matters and organic acids on the surface of the carbon media are further recycled.

The waste water from the carbon medium absorption unit 2 enters the anion exchange system 3 with two parallel anion exchange resins as filler fixed beds to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the discharged waste water is 5 ppm. When the concentration of organic acid in the discharged waste water is 20ppm, after the anion exchange resin is gradually adsorbed and saturated, the parallel fixed bed is switched, and 5% ammonia water is used for regeneration, and the regeneration liquid is discharged. When the outlet concentration of ammonia water reaches 95% of the inlet concentration % or more, it indicates that the resin has been fully regenerated, stop the regeneration, use air to blow off the lye in the system, complete the regeneration work, and can be further switched to use.

Example 5

Wastewater from the methanol aromatization system first enters a single high-temperature stripper. The temperature at the bottom of the stripper is 120oC to remove a large amount of organic matter and organic acids. The COD (Cr) of the effluent is 500 and the concentration of organic acids is 150ppm.

The waste water from the stripping tower enters the carbon medium absorption device 2 composed of two parallel absorption towers, wherein the carbon medium is activated carbon, and the absorption tower is composed of 30 layers of activated carbon absorption layers, and the organic matter and organic acid in the waste water are absorbed and removed by activated carbon, The COD (Cr) of its outlet wastewater is 120, and the organic acid concentration is 40ppm. When the COD concentration in the outlet wastewater of the carbon media absorption device is higher than 200ppm or the concentration of organic acid is higher than 60ppm, the absorption tower is switched, and then the carbon material in the absorption tower is regenerated, and the high-temperature water vapor is introduced from the water vapor inlet to remove the adsorption. The organic matters and organic acids on the surface of the carbon media are further recycled.

The waste water from the carbon medium absorption unit 2 enters the anion exchange system 3 with two parallel anion exchange resins as filler fixed beds to remove the organic acid in the organic waste water, so that the concentration of the organic acid in the discharged waste water is 5 ppm. When the concentration of organic acid in the discharged waste water is 20ppm, after the anion exchange resin is gradually adsorbed and saturated, the parallel fixed bed is switched, and 5% ammonia water is used for regeneration, and the regeneration liquid is discharged. When the outlet concentration of ammonia water reaches 95% of the inlet concentration % or more, it indicates that the resin has been fully regenerated, stop the regeneration, use air to blow off the lye in the system, complete the regeneration work, and can be further switched to use.

Claims (7)

1. A system for methanol aromatization process wastewater treatment, characterized in that, comprising: A high-temperature stripping unit (1) for removing most of the organic matter in the wastewater; Connect the high-temperature stripping unit (1), be used to remove the carbon medium absorption unit (2) of organic acid and part organic matter in the waste water of the high-temperature stripping unit (1), and the carbon medium absorption unit (2) consists of a or multiple carbon media absorption layers, the carbon media being one or more of carbon nanotubes, graphene, expanded graphite, and carbon fibers; And an anion exchange system (3) connected to the carbon medium absorption device (2) for reducing the organic acid in the waste water of the carbon medium absorption device (2) to a trace amount. 2. The system for methanol aromatization process wastewater treatment according to claim 1, characterized in that, the high-temperature stripping device (1) is composed of one or two stripping towers. 3. The system for methanol aromatization process wastewater treatment according to claim 1, characterized in that, the anion exchange system (3) consists of two parallel fixed beds filled with anion exchange resins. 4. the wastewater treatment method based on the said methanol aromatization wastewater treatment system of claim 1, is characterized in that, comprises the following steps: a) Sewage methanol aromatization process wastewater first enters the high-temperature stripping unit (1), the temperature at the bottom of the high-temperature stripping unit (1) is 100-120 ° C, in which a large amount of organic matter and a small amount of organic acid are removed, COD (Cr ) is less than 600ppm, and the concentration of organic acid is less than 200ppm; b) The waste water from the high-temperature stripping unit (1) enters the carbon medium absorption unit (2), absorbs and removes organic matter and a part of organic acids in the waste water, the COD (Cr) of the waste water at the outlet is less than 200ppm, and the concentration of organic acids is less than 60ppm; c) The waste water from the carbon outlet medium absorption device (2) enters the anion exchange system (3) to remove the organic acid in the waste water, so that the concentration of the organic acid in the discharged waste water is less than 20ppm. 5. according to the treatment method of the described methanol aromatization process waste water of claim 4, it is characterized in that, described anion exchange removes the organic acid in the waste water, comprises the steps: a) The waste water from the carbon medium absorption device (2) passes through the weakly basic anion exchange system (3), and part of the organic acid is adsorbed, and the organic acid content in the effluent of the anion exchange system (3) is less than 10 ppm; b) Anion exchange system (3) The organic acid content in the effluent water is greater than 20ppm, the resin adsorption is close to saturation, stop the adsorption, and blow out the liquid in the system with air; c) passing 5-10wt% weak alkali solution into the saturated ion exchange system (3) for desorption; d) The ion exchange system after desorption (3) uses air to blow out the lye. 6. The method for treating methanol aromatization process wastewater according to claim 5, characterized in that, said lye comprises ammonia, sodium hydroxide, and calcium hydroxide. 7. according to the treatment method of the described methanol aromatization process waste water of claim 5, it is characterized in that, described carbon medium absorber (2) absorbs and removes organic matter and organic acid in waste water, comprises the steps: a) The waste water from the high temperature stripping unit (1) absorbs the organic matters and organic acids in the waste water through the carbon media absorption unit (2) equipped with carbon materials, the COD of the effluent is less than 200ppm, and the organic acid content is less than 50ppm; b) The COD of the effluent in the carbon medium absorption device (2) is close to 200ppm, the organic acid is close to 60ppm, the carbon material is close to saturation, stop the adsorption, and use air to blow out the liquid of the device; c) Using high-temperature water vapor to remove the organic matter and organic acid adsorbed on the surface of the carbon medium, and further recycling.