CN219239316U

CN219239316U - Adsorption device for raffinate in DMF (dimethyl formamide) synthetic leather wastewater

Info

Publication number: CN219239316U
Application number: CN202320328309.8U
Authority: CN
Inventors: 杨磊; 牟晓菲; 贺磊; 唐婷婷; 王杨杨; 吴萍; 陈旭堂; 梁坤; 张圣杰
Original assignee: China Haisum Engineering Co Ltd
Current assignee: China Haisum Engineering Co Ltd
Priority date: 2023-02-24
Filing date: 2023-02-24
Publication date: 2023-06-23
Anticipated expiration: 2033-02-24

Abstract

The utility model discloses an adsorption device for raffinate of DMF synthetic leather wastewater, which comprises a raffinate storage tank for storing the raffinate of DMF synthetic leather wastewater, an adsorption unit communicated with the raffinate storage tank and an analysis tower; the adsorption unit comprises a plurality of adsorption towers, the liquid outlets at the bottoms of the adsorption towers and the analytic towers are communicated with the treated wastewater storage tank through a centrifugal pump IV, the gas outlets at the tops of the adsorption towers and the analytic towers are communicated with a condenser, and the liquid outlet at the bottom of the condenser is communicated with the DMF storage tank. The process flow is simple, the equipment is simplified, and automatic continuous operation can be realized.

Description

Adsorption device for raffinate in DMF (dimethyl formamide) synthetic leather wastewater

Technical Field

The utility model relates to an adsorption device for raffinate of DMF synthetic leather wastewater, in particular to adsorption of DMF in the raffinate and regeneration of an adsorbent, and belongs to the technical field of green and environment-friendly technology.

Background

N, N-dimethylformamide, abbreviated as DMF, has a molecular formula of C3H7NO, a boiling point of 152.8 ℃, and DMF is a colorless transparent liquid with ammonia smell at normal temperature.

By 2021, the apparent domestic DMF consumption was 53 ten thousand tons. The specific application industries are as follows:

1) Polyurethane synthetic leather industry. It is counted that there are 2000 or more synthetic leather enterprises of the whole national size at present, wherein the synthetic leather enterprises with the above scale are about 450. The synthetic leather enterprises are mainly distributed in the peripheral areas of equal-length triangles and bead triangles of Zhejiang province, fujian province, guangdong province, jiangsu province and Anhui province of China. DMF is used as an important solvent in the synthetic leather industry, and accounts for 59% in each application industry, and the annual consumption is 30-35 ten thousand tons.

2) Pesticide and pharmaceutical intermediate industries. DMF is used as a reaction solvent and an important raw material, is widely applied to pesticide and medicine industries, has annual consumption of 8-10 ten thousand tons and accounts for 17% in each application industry.

3) Food and electronics industry. DMF is used as an excellent solvent, has wide application in the electronic industry and the food industry, has annual consumption of 7-9 ten thousand tons and accounts for 16% in each application industry.

4) Other industries. DMF is used in other application industries, such as dye industry, fiber industry, petrochemical industry, metallurgical industry, etc. The annual consumption is 2-6 ten thousand tons, and the annual consumption accounts for 8% in each application industry.

The synthetic leather industry is the largest consumer of DMF and is also the largest discharger of DMF-containing wastewater. The wastewater discharge amount of DMF (dimethyl formamide) is close to 1 hundred million tons only in the synthetic leather industry every year. The DMF wastewater recovery treatment method in the synthetic leather industry is mainly divided into the following categories: physical and chemical methods, biochemical methods, and chemical methods. The most common is a physical and chemical method, the physical and chemical method does not change the molecular structure of DMF, and the recovery mode is mainly based on the combination of rectification, extraction and adsorption.

Disclosure of Invention

The technical problems to be solved by the utility model are as follows: the extraction-rectification treatment device for the DMF synthetic leather wastewater has the problems that DMF in raffinate and trace extractant chloroform can not be effectively separated and adsorbent can not be effectively regenerated during post-treatment.

In order to solve the above problems, the present utility model provides

The utility model also provides an adsorption device for the raffinate of the DMF synthetic leather wastewater, which sequentially comprises a raffinate storage tank for storing the raffinate of the DMF synthetic leather wastewater, an adsorption unit communicated with the raffinate storage tank and an analysis tower; the adsorption unit comprises a plurality of adsorption towers, the liquid outlets at the bottoms of the adsorption towers and the analytic towers are communicated with the treated wastewater storage tank through a centrifugal pump IV, the gas outlets at the tops of the adsorption towers and the analytic towers are communicated with a condenser, and the liquid outlet at the bottom of the condenser is communicated with the DMF storage tank. The device has simple structure and simplified process, and can realize automatic continuous operation. The DMF content in the waste water after adsorption can be as low as 5ppm, and the chloroform concentration can be as low as 0.3ppm.

Preferably, the bottom outlet of each adsorption tower in the adsorption unit is provided with a four-way valve, one side of the upper inlet is provided with a three-way valve, each four-way valve is communicated with the three-way valve at the upper part of the adjacent adsorption tower through a centrifugal pump, the three-way valves are communicated with each other, and the four-way valves are communicated with each other; the adsorption towers are connected in series or in parallel according to different states of the valve.

Preferably, the air conditioner further comprises a blower for heating the air and then sending the heated air into the adsorption tower and the desorption tower, and a blower for blowing the air into the heat exchanger.

Preferably, the adsorption tower and the analysis tower are filled with coconut shell activated carbon, and the particle size of the coconut shell activated carbon is 1-2 mm. The saturated adsorption quantity of the coconut shell activated carbon to DMF is 53.5mg/g.

During the adsorption operation, raffinate enters from the top of the adsorption tower, is discharged from the bottom of the adsorption tower after being adsorbed by the coconut shell activated carbon serving as an adsorption medium, and is pumped into the adsorption tower at the next stage for further adsorption until the adsorbed liquid reaches the discharge standard. And the wastewater which is qualified in adsorption is conveyed into a treated wastewater storage tank through a centrifugal pump, and unqualified wastewater is conveyed to an inlet of an adsorption tower through the centrifugal pump again for further adsorption treatment. After the adsorption medium cocoanut active carbon is saturated, hot air is needed to be used for carrying out adsorbent regeneration analysis treatment.

During the analysis, hot air enters from the bottom of the analysis tower and fully contacts with the adsorption saturated coconut shell activated carbon. Under the action of high-temperature airflow, DMF and trace chloroform in the coconut shell activated carbon are desorbed to enter hot air. And condensing DMF and trace chloroform in hot air by a condenser, separating out, entering a DMF storage tank, and discharging non-condensable air from the top of the condenser. In this adsorption equipment, be provided with saturated steam pipeline, mainly used air's heating still is provided with cooling water pipeline, mainly used hot air's condensation.

Compared with the technology for treating DMF wastewater by the traditional biochemical method, the utility model has the beneficial effects that:

1. after the raffinate is treated by the adsorption device, the DMF content in the wastewater can be as low as 5ppm, and the chloroform concentration in the wastewater can be as low as 0.3ppm, so that the wastewater reaches the first-level discharge standard specified by national Integrated wastewater discharge Standard (GB 8978-1996).

2. The adsorption device is convenient to operate. Different adsorption modes are adopted according to different working conditions, and automatic control can be realized.

3. Can be operated continuously. On-line adsorption and analysis can realize continuous feeding and continuous discharging.

4. The treatment capacity is large. When the size of the adsorption tower reaches phi 1600mm multiplied by 13200mm, 100 ten thousand tons/year of synthetic leather wastewater with 20% of DMF content can be treated.

Drawings

Fig. 1 is a schematic diagram of an adsorption device provided by the utility model.

Detailed Description

In order to make the utility model more comprehensible, preferred embodiments accompanied with figures are described in detail below.

As shown in FIG. 1, the adsorption device for the raffinate of the DMF synthetic leather wastewater provided by the utility model comprises an adsorption unit consisting of 3 adsorption towers and a resolution tower 4, wherein the 3 adsorption towers are respectively an adsorption tower I1, an adsorption tower II 2 and an adsorption tower III 3, coconut shell activated carbon is filled in the adsorption tower and the resolution tower 4, and the particle size of the coconut shell activated carbon is 1-2 mm. The outlet of the bottom of each adsorption tower in the adsorption unit is respectively communicated with a four-way valve, the inlet of the upper part is respectively communicated with a three-way valve, and the inlet and the outlet of the analysis tower 4 are respectively provided with a three-way valve. The three adsorption towers and four three-way valves at the inlet of the resolving tower 4 are communicated with each other. The four-way valve at the bottom of the adsorption tower I1 is communicated with the inlet of the centrifugal pump I5, the outlet of the centrifugal pump I5 is communicated with the three-way valve at the inlet of the adsorption tower II 2, the four-way valve at the bottom of the adsorption tower II 2 is communicated with the inlet of the centrifugal pump II 6, the outlet of the centrifugal pump II 6 is communicated with the three-way valve at the inlet of the adsorption tower III 3, the four-way valve at the bottom of the adsorption tower III 3 is communicated with the inlet of the centrifugal pump III 7, and the outlet of the centrifugal pump III 7 is communicated with the three-way valve at the inlet of the analysis tower 4.

And a plurality of adsorption towers in the adsorption unit are connected in series or in parallel according to different states of the valve.

The raffinate storage tank 15 for storing the raffinate of the DMF synthetic leather wastewater is communicated with a three-way valve at the inlet side of the first 1 of the adsorption tower in the adsorption unit through a centrifugal pump five 9.

The adsorption unit of intercommunication, the resolution column 4, the adsorption unit includes a plurality of adsorption towers, and the liquid outlet of adsorption tower, resolution column 4 bottom is through centrifugal pump four 8 and the waste water storage tank 14 intercommunication after handling, and the gas outlet at adsorption tower, resolution column 4 top communicates with condenser 12, and the liquid outlet and the DMF storage tank 13 intercommunication of condenser 12 bottom.

The adsorption apparatus further includes a blower 10 for heating the air and feeding the heated air into the adsorption tower and the desorption tower 4, and a blower 10 for blowing the air into the heat exchanger 11. The heat exchanger 11 is respectively filled with steam and cold air for heat exchange, and condensed water and hot air are respectively obtained. The hot air is communicated with four-way valves at the bottom outlets of the three adsorption towers and three-way valves at the bottom outlets of the analysis tower 4. The four-way valve of the bottom outlet of the three adsorption towers and the three-way valve of the bottom outlet of the analytic tower 4 are also communicated with the inlet of the centrifugal pump IV 8, the outlet of the centrifugal pump IV 8 is respectively communicated with the three-way valve of the inlet of the adsorption tower I1 and the treated wastewater storage tank 14, and the treated wastewater storage tank 14 discharges treated wastewater through the centrifugal pump IV 17.

The top gas outlets of the three adsorption towers and the analytic tower 4 are communicated with a condenser 12, the condenser 12 is communicated with circulating cooling water, noncondensable gas is discharged from the top of the condenser 12, liquid obtained after treatment of the condenser 12 enters a DMF storage tank 13, and the DMF storage tank 13 is communicated with a centrifugal pump 16 to discharge DMF.

The three adsorption towers and the analysis tower 4 are core equipment of a raffinate adsorption device of the DMF synthetic leather wastewater. The upper end enclosure and the lower end enclosure of the adsorption tower are both elliptical end enclosures, or conical end enclosures, and the elliptical end enclosures are preferred.

The adsorption tower 1, the adsorption tower 2, the adsorption tower 3 and the desorption tower 4 are filled with coconut shell activated carbon, and the particle size of the coconut shell activated carbon is 1-2 mm. The coconut shell activated carbon is filled in a regular packing mode, so that the coconut shell activated carbon is convenient to replace regularly. The saturated adsorption quantity of the coconut shell activated carbon to DMF is 53.5mg/g.

In the adsorption unit, a saturated steam pipeline is arranged for heating air. Meanwhile, a cooling water pipeline is arranged for condensing hot air.

During adsorption, the raffinate of the synthetic leather wastewater containing DMF and trace chloroform enters a raffinate storage tank 15 and is pumped into the top of the first adsorption tower 1 by a centrifugal pump five 9. And the raffinate is discharged from the bottom of the first adsorption tower 1 after being adsorbed by the coconut shell activated carbon as an adsorption medium. The discharged raffinate is pumped into the top of the second adsorption tower 2 of the next stage by the first centrifugal pump 5 for further adsorption. The raffinate discharged from the bottom of the second adsorption tower 2 is pumped into the top of the third adsorption tower 3 of the next stage by the second centrifugal pump 6 for further adsorption. Pumping raffinate discharged from the bottom of the adsorption tower III 3 into a treated wastewater storage tank 14 through a centrifugal pump IV 8 after the raffinate is detected to be qualified, and then discharging the treated wastewater to a sewage treatment plant through a centrifugal pump seven 17; and (3) pumping raffinate discharged from the bottom of the adsorption tower III, passing through a centrifugal pump IV 8 after unqualified detection, and pumping the raffinate into the top of the adsorption tower I1 again for further adsorption.

After the adsorption medium cocoanut active carbon is saturated, hot air is needed to be used for carrying out adsorbent regeneration analysis treatment. At the time of analysis, air is sent to the heat exchanger 11 through the blower 10. The hot air heated by the steam enters from the bottom of the desorption tower 4. Under the action of high-temperature airflow, DMF and trace chloroform in the coconut shell activated carbon are desorbed and enter hot air, and the hot air is discharged from the top of the resolving tower 4 and enters the condenser 12. DMF and trace chloroform in the hot air are condensed and separated out by a condenser 12, enter a DMF storage tank 13, and noncondensable air is discharged from the top of the condenser 12. The condenser 12 cooling medium adopts circulating cooling water, and flows through the condenser 12 from bottom to top in a countercurrent manner from the tube side.

In different embodiments, 3 adsorption towers for adsorption can be connected in series or in parallel, and the switching and modes are realized through a three-way valve at the top of the tower, a four-way valve at the bottom of the tower and a lifting pump between the adsorption towers.

The device is adopted to adsorb the raffinate of the DMF synthetic leather wastewater, and the method mainly comprises two working procedures of adsorption and analysis. And transferring the DMF and the trace chloroform in the aqueous solution into an adsorbent through an adsorption tower, and then desorbing and recycling the DMF and the trace chloroform in the adsorbent through analysis. The process flow is simple, the equipment is simplified, and automatic continuous operation can be realized. The DMF content in the waste water after adsorption can be as low as 5ppm, and the chloroform concentration can be as low as 0.3ppm.

After the raffinate of the synthetic leather wastewater containing DMF and trace chloroform passes through an adsorption device, the DMF adsorption rate is 97.22%, the DMF content in the wastewater after adsorption can be as low as 5ppm, and the chloroform concentration can be as low as 0.3ppm. The time required for the adsorption process was 3 hours, and the time required for the desorption process was 1.5 hours.

Claims

1. The adsorption device for the raffinate of the DMF synthetic leather wastewater is characterized by sequentially comprising a raffinate storage tank (15) for storing the raffinate of the DMF synthetic leather wastewater, an adsorption unit communicated with the raffinate storage tank (15) and a resolution tower (4); the adsorption unit comprises a plurality of adsorption towers, a liquid outlet at the bottom of each adsorption tower and each analytic tower (4) is communicated with the treated wastewater storage tank (14) through a centrifugal pump IV (8), an air outlet at the top of each adsorption tower and each analytic tower (4) is communicated with the corresponding condenser (12), and a liquid outlet at the bottom of each condenser (12) is communicated with the corresponding DMF storage tank (13).

2. The adsorption device of the raffinate from the DMF synthetic leather wastewater according to claim 1, wherein a four-way valve is arranged at the bottom outlet of each adsorption tower in the adsorption unit, a three-way valve is arranged at one side of the upper inlet, each four-way valve is communicated with the three-way valve at the upper part of the adjacent adsorption tower through a centrifugal pump, the three-way valves are communicated with each other, and the four-way valves are communicated with each other; the adsorption towers are connected in series or in parallel according to different states of the valve.

3. The adsorption device for the raffinate of the DMF synthetic leather wastewater according to claim 1, which is characterized by further comprising a blower (10) for sending air into the adsorption tower and the analysis tower (4) after heating and a blower (10) for blowing the air into the heat exchanger (11).

4. The adsorption device for the raffinate of the DMF synthetic leather wastewater, as claimed in claim 1, is characterized in that the adsorption tower and the analysis tower (4) are filled with coconut shell activated carbon, and the particle size of the coconut shell activated carbon is 1-2 mm.