Method for high temperature wastewater treatment and reuse in MTO process

Abstract

The invention relates to a method for treating and reusing high-temperature stripping purified wastewater produced in the process of transferring oxygenated compounds into olefins by using a high-temperature separation membrane. The combination process can effectively remove the impurities such as metal ions and organic micro-molecules and the like in stripping purified water, and the treated purified water in a tower kettle can meet the quality requirements of makeup water for middle and low-pressure boilers or the quality requirements of the makeup water in the MTO process. The invention effectively overcomes the defects exiting in the method for treating and reusing the stripping purified water without condensation in the MTO process, and lowers or reduces the consumption of circulating cooling water in the process of cooling firstly and then treating, thereby saving a large amount of boiler water and recycling the thermal energy of produced high temperature wastewater, and providing a stable and efficient way for high temperature wastewater treatment and reuse of relevant enterprises.

Description

[technical field]

[0001] The invention relates to the field of wastewater treatment, in particular to a method for treating high-temperature wastewater of an MTO process by utilizing membrane separation technology. [Background technique]

[0002] Low-carbon olefins such as ethylene and propylene are important organic chemical raw materials and play a very important role in modern petroleum and chemical industries. Traditionally, the source of ethylene and propylene is mainly steam cracking of hydrocarbons, and the raw material is mainly naphtha. The research and development of methanol to light olefins (MTO) process is a new process route for the production of chemical products from non-petroleum resources. As the technology of producing methanol from coal or natural gas through synthesis gas is becoming more and more mature, MTO has become a production route that has attracted much attention.

[0003] The chemical reaction equation and thermal effect of using methanol as ...

Examples

Embodiment 1

[0039] The high-temperature wastewater treatment process of the stripping tower kettle is as follows: figure 1 As shown, the 70°C MTO process stripping tower purified water A is discharged into the sedimentation separation tank 1, and the main water quality parameters include: the wastewater temperature is 70°C, the pH is 5.5, the turbidity is 86.9NTU, and the oil content is 8.9mg / L , the total iron content is 45.2mg / L, SiO 2 The content is 8.9μg / L.

[0040] Firstly, the stripped purified water is adjusted to pH 8.0, mixed by pipeline mixer, and discharged into sedimentation separation tank 1. At the bottom of the sedimentation separation tank, microporous aeration device B is used for aeration operation, and the aeration flow rate is 50L / min. The hydraulic residence time of alkali-adjusted aeration is 20 minutes, and the precipitated colloidal substances are discharged through the sludge discharge port C. The mixed wastewater after alkali-adjusted aeration is discharged into...

Embodiment 2

[0044] High temperature wastewater treatment process such as figure 1 As shown, the 80°C MTO process stripper purified water A is discharged into the sedimentation separation tank 1, wherein the quality of the stripper purified water is as described in Example 1, and the same pretreatment process in Example 1 is adopted. After pretreatment The process water quality is as described in Example 1.

[0045] The stripped purified water after pretreatment is sent to the ultrafiltration system 3 through the centrifugal pump 2. The pore size of the ultrafiltration membrane is 0.1 μm high-temperature resistant organic ultrafiltration membrane Duratherm HWS UF 2540, and the effective membrane area is 2.3m 2 , the ultrafiltration membrane filtration flux is 200L / m 2 h, the water supply pressure of the ultrafiltration membrane system is 0.2 bar, and the recovery rate of the ultrafiltration system is adjusted to 95%. 1.2mg / L, total iron content less than 0.04mg / L, SiO 2 The content is 3...

Embodiment 3

[0048] High temperature wastewater treatment process such as figure 1 As shown, the 80 ° C MTO process stripper purified water A is discharged into the precipitation separation system 1, wherein the water quality of the stripper tower is as described in Example 1, and the same pretreatment process in Example 1 is adopted. After pretreatment The process water quality is as described in Example 1.

[0049] The pretreated wastewater is sent to the ultrafiltration system 3 through the centrifugal pump 2. The pore size of the ultrafiltration membrane is 0.02 μm and the 19-channel tubular ceramic ultrafiltration membrane is selected, and the effective membrane area is 1m 2 , the membrane filtration flux is 100L / m 2 h, the water supply pressure of the ultrafiltration membrane system is 0.15MPa, the recovery rate of the ultrafiltration system is 90%, the ultrafiltration concentrated water is circulated to the sedimentation tank 1, and the ultrafiltration water quality is pH 8.63, the...

[technical field]

[0001] The invention relates to the field of wastewater treatment, in particular to a method for treating high-temperature wastewater of an MTO process by utilizing membrane separation technology. [Background technique]

[0002] Low-carbon olefins such as ethylene and propylene are important organic chemical raw materials and play a very important role in modern petroleum and chemical industries. Traditionally, the source of ethylene and propylene is mainly steam cracking of hydrocarbons, and the raw material is mainly naphtha. The research and development of methanol to light olefins (MTO) process is a new process route for the production of chemical products from non-petroleum resources. As the technology of producing methanol from coal or natural gas through synthesis gas is becoming more and more mature, MTO has become a production route that has attracted much attention.

[0003] The chemical reaction equation and thermal effect of using methanol as ...

Examples

Embodiment 1

[0039] The high-temperature wastewater treatment process of the stripping tower kettle is as follows: figure 1 As shown, the 70°C MTO process stripping tower purified water A is discharged into the sedimentation separation tank 1, and the main water quality parameters include: the wastewater temperature is 70°C, the pH is 5.5, the turbidity is 86.9NTU, and the oil content is 8.9mg / L , the total iron content is 45.2mg / L, SiO 2 The content is 8.9μg / L.

[0040] Firstly, the stripped purified water is adjusted to pH 8.0, mixed by pipeline mixer, and discharged into sedimentation separation tank 1. At the bottom of the sedimentation separation tank, microporous aeration device B is used for aeration operation, and the aeration flow rate is 50L / min. The hydraulic residence time of alkali-adjusted aeration is 20 minutes, and the precipitated colloidal substances are discharged through the sludge discharge port C. The mixed wastewater after alkali-adjusted aeration is discharged into...

Embodiment 2

[0044] High temperature wastewater treatment process such as figure 1 As shown, the 80°C MTO process stripper purified water A is discharged into the sedimentation separation tank 1, wherein the quality of the stripper purified water is as described in Example 1, and the same pretreatment process in Example 1 is adopted. After pretreatment The process water quality is as described in Example 1.

[0045] The stripped purified water after pretreatment is sent to the ultrafiltration system 3 through the centrifugal pump 2. The pore size of the ultrafiltration membrane is 0.1 μm high-temperature resistant organic ultrafiltration membrane Duratherm HWS UF 2540, and the effective membrane area is 2.3m 2 , the ultrafiltration membrane filtration flux is 200L / m 2 h, the water supply pressure of the ultrafiltration membrane system is 0.2 bar, and the recovery rate of the ultrafiltration system is adjusted to 95%. 1.2mg / L, total iron content less than 0.04mg / L, SiO 2 The content is 3...

Embodiment 3

[0048] High temperature wastewater treatment process such as figure 1 As shown, the 80 ° C MTO process stripper purified water A is discharged into the precipitation separation system 1, wherein the water quality of the stripper tower is as described in Example 1, and the same pretreatment process in Example 1 is adopted. After pretreatment The process water quality is as described in Example 1.

[0049] The pretreated wastewater is sent to the ultrafiltration system 3 through the centrifugal pump 2. The pore size of the ultrafiltration membrane is 0.02 μm and the 19-channel tubular ceramic ultrafiltration membrane is selected, and the effective membrane area is 1m 2 , the membrane filtration flux is 100L / m 2 h, the water supply pressure of the ultrafiltration membrane system is 0.15MPa, the recovery rate of the ultrafiltration system is 90%, the ultrafiltration concentrated water is circulated to the sedimentation tank 1, and the ultrafiltration water quality is pH 8.63, the...

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