Caprolactam benzene extraction wastewater treatment system

Abstract

The utility model discloses a caprolactam benzene extraction wastewater treatment system which comprises a wastewater buffer tank, the wastewater buffer tank is connected with a desulfurization reactor, the desulfurization reactor is connected with a Ca (OH) 2 conveying system, a discharge port of the desulfurization reactor is sequentially communicated with a desulfurization precipitator through a pipeline, and the Ca (OH) 2 conveying system is connected with a Ca (OH) 2 conveying system. A liquid outlet in the upper part of the desulfurization precipitator is communicated with a decalcification reactor through a pipeline, the decalcification reactor is also connected with a CO2 conveying system, and a discharge port of the decalcification reactor is sequentially communicated with the decalcification precipitator through a pipeline. The concentration of SO4 < 2-> in the caprolactam benzene extraction wastewater is reduced to 2000mg / below through desulfurization reaction. And through a decalcification reaction, the concentration of newly introduced Ca < 2 + > is reduced to 2000 mg / below. A flocculating agent and a coagulant aid are respectively added after the desulfurization reaction and the decalcification reaction, so that the separation effect of calcium sulfate, calcium carbonate and wastewater can be improved. The system does not need to consume steam.

Description

TECHNICAL FIELD

[0001] The utility model relates to wastewater treatment technical field especially relates to a kind of for caprolactam benzene extraction wastewater treatment system. BACKGROUND

[0002] Caprolactam is an important raw material for producing nylon-6, engineering plastics, film and other chemical products, and the production chain of caprolactam belongs to the category of "three high", i.e. high energy consumption, high pollution and high input.

[0003] In the production of caprolactam, the rearrangement reaction process is that 20% cyclohexanone oxime solution in cyclohexane-cyclohexanone oxime reacts to form caprolactam sulfate under the catalysis of fuming sulfuric acid, caprolactam sulfate reacts with ammonia gas in a saturated ammonium sulfate system to form caprolactam and ammonium sulfate, and after separation, amide oil and ammonium sulfate are obtained, and the amide oil is then subjected to benzene extraction, process water back extraction, hydrogenation and evaporation distillation to obtain high-quality caprolactam.

[0004] In the benzene extraction process of amide oil, amide oil and benzene are counter-extracted in an extraction column, benzene caprolactam solution is obtained at the top of the column, and caprolactam residue is obtained at the bottom of the column, and after stripping and recovery, extraction wastewater is obtained, and the components of the extraction wastewater are shown in Table 1 below.

[0005] Table 1

[0006]

[0007] The components of caprolactam extraction wastewater are complex, and the COD and ammonia nitrogen are both high, which are difficult to handle. The traditional process is to obtain concentrated liquid with high solid content by concentration, and the concentrated liquid is then subjected to waste liquid incineration to produce steam. In this process, there are three problems: first, it is difficult to handle the ammonia gas and benzene gas generated during concentration, and the environment is polluted; second, the recovery system has a great impact on the quality of caprolactam products; third, the concentrated liquid is difficult to transport, and the process fluctuates greatly; fourth, the concentrated wastewater is discharged to the sewage system, and the cost of sewage treatment is high. If caprolactam extraction wastewater is directly incinerated, the content of sulfur dioxide in the tail gas is high, which pollutes the environment. INVENTION CONTENTS

[0008] The utility model aims to provide a kind of for caprolactam benzene extraction wastewater treatment system, replace original concentrated device, after desulfurization and decalcification of caprolactam benzene extraction wastewater, it is sent to synthetic ammonia device for the configuration of coal water slurry, the problem of complex components of caprolactam extraction wastewater is solved, and the steam consumption is reduced, and the cost problem of sewage treatment is reduced.

[0009] The technical scheme adopted by the utility model is as follows:

[0010] A kind of for caprolactam benzene extraction wastewater treatment system, including wastewater buffer tank, the wastewater buffer tank is connected with desulfurization reactor, the desulfurization reactor is connected with Ca (OH) 2 delivery system, the desulfurization reactor discharge outlet is sequentially communicated with desulfurization precipitator by pipeline, desulfurization precipitator upper liquid outlet is communicated with desulfurization reactor by pipeline, desulfurization reactor is also connected with CO 2 delivery system, the desulfurization reactor discharge outlet is sequentially communicated with and desulfurization precipitator by pipeline.

[0011] Preferably, the desulfurization precipitator bottom is communicated with desulfurization filter pressing system by pipeline, and the desulfurization precipitator is connected with desulfurization filter pressing system and wastewater external delivery system respectively.

[0012] Preferably, the desulfurization reactor discharge outlet is sequentially communicated with first pipeline mixer, second pipeline mixer and desulfurization precipitator by pipeline, and the desulfurization reactor discharge outlet is sequentially communicated with third pipeline mixer, fourth pipeline mixer and desulfurization precipitator by pipeline.

[0013] Preferably, the first pipeline mixer and third pipeline mixer are communicated with flocculant delivery system by pipeline respectively, and the second pipeline mixer and fourth pipeline mixer are communicated with coagulant delivery system by pipeline respectively.

[0014] Preferably, the desulfurization reactor and desulfurization reactor are internally provided with stirring device, and the desulfurization reactor and desulfurization reactor are internally provided with distributor respectively.

[0015] Preferably, the desulfurization precipitator and desulfurization precipitator are internally provided with packing support, and the packing support is provided with packing layer, and the flow stabilizing cylinder passes through the packing layer, and the water outlet groove is arranged above the packing layer, and the flow stabilizing cylinder is arranged below the packing layer.

[0016] Further preferably, the flow stabilizing cylinder is arranged below the packing layer in inverted funnel shape.

[0017] Further preferably, the second pipeline mixer and desulfurization precipitator are communicated above the packing layer, and the second pipeline mixer and desulfurization precipitator are communicated above the packing layer.

[0018] Compared with the prior art, the utility model has the following technical effects:

[0019] 1, by desulfurization reaction, the concentration of SO4 2- In caprolactam benzene extraction wastewater is reduced to 2000 mg / or less.

[0020] 2, by desulfurization reaction, the concentration of Ca 2+ Newly introduced is reduced to 2000 mg / or less.

[0021] 3. After the desulfurization reaction and the decalcification reaction, flocculants and coagulants are added respectively, so that the separation effect of calcium sulfate, calcium carbonate and wastewater can be improved.

[0022] 4. The system does not need to consume steam. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced.

[0024] Figure 1 is a structural schematic diagram of the present application.

[0025] Figure 2 is a structural schematic diagram of the desulfurization precipitator and the decalcification precipitator.

[0026] In the figure: wastewater buffer tank 1, desulfurization reactor 2, first pipeline mixer 3, second pipeline mixer 4, desulfurization precipitator 5, decalcification reactor 6, third pipeline mixer 7, fourth pipeline mixer 8, decalcification precipitator 9, CaOH2 delivery system 10, PAC delivery system 11, PAM delivery system 12, desulfurization filter pressing system 13, CO2 delivery system 14, decalcification filter pressing system 15, wastewater delivery system 16, filler support 17, filler layer 18, flow stabilizing cylinder 19, water outlet tank 20. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0028] Embodiment 1

[0029] Please refer to Figure 1 , a caprolactam benzene extraction wastewater treatment system, comprising a wastewater buffer tank 1, the wastewater buffer tank 1 is connected with a desulfurization reactor 2, the desulfurization reactor 2 is connected with a CaOH2 delivery system 10, the desulfurization reactor 2 is sequentially communicated with a desulfurization precipitator 5 through a pipeline, a liquid outlet at the upper part of the desulfurization precipitator 5 is communicated with a decalcification reactor 6 through a pipeline, the decalcification reactor 6 is also connected with a CO2 delivery system 14, and a discharge port of the decalcification reactor 6 is sequentially communicated with a decalcification precipitator 9 through a pipeline.

[0030] Preferably, the bottom of the desulfurization precipitator 5 is communicated with a desulfurization filter pressing system 13 through a pipeline, and the decalcification precipitator 9 is connected with a decalcification filter pressing system 15 and a wastewater delivery system 16 respectively.

[0031] Preferably, the desulfurization reactor 2 outlet is communicated with the first pipeline mixer 3, the second pipeline mixer 4 and the desulfurization precipitator 5 in sequence through pipelines, and the desulfurization reactor 6 outlet is communicated with the third pipeline mixer 7, the fourth pipeline mixer 8 and the desulfurization precipitator 9 in sequence through pipelines.

[0032] Preferably, the first pipeline mixer 3 and the third pipeline mixer 7 are communicated with the flocculant conveying system 11 through pipelines respectively, and the second pipeline mixer 4 and the fourth pipeline mixer 8 are communicated with the coagulant conveying system 12 through pipelines respectively.

[0033] Preferably, the desulfurization reactor 2 and the desulfurization reactor 6 are internally provided with stirring devices, and the wastewater inlet and the CaOH2 inlet of the desulfurization reactor 2 are respectively provided with distributors, and the wastewater inlet and the CO2 inlet of the desulfurization reactor 6 are respectively provided with distributors.

[0034] Preferably, the desulfurization precipitator 5 and the desulfurization precipitator 9 are internally provided with a filler support 17, the filler support 17 is provided with a filler layer 18, a flow stabilizing cylinder 19 penetrates through the filler layer 18, an outlet water groove 20 is arranged above the filler layer 18, and both ends of the flow stabilizing cylinder 19 are located below the outlet water groove 20 and the filler layer 18 respectively. The filler layer 18 separates the precipitate and the material fluid, and the liquid is moved upward through the flow stabilizing cylinder after being separated and settled at the lower part. The material in the flow stabilizing cylinder can be further separated during the upward movement, and is not affected by the flow rate of the feed, and the material in the flow stabilizing cylinder is equivalent to a stable flow state.

[0035] Further preferably, the flow stabilizing cylinder 19 is in an inverted funnel shape below the filler layer 18.

[0036] Further preferably, the communication between the second pipeline mixer 4 and the desulfurization precipitator 5 is located above the filler layer 18, and the communication between the second pipeline mixer 4 and the desulfurization precipitator 5 is located above the filler layer 18. The function of this is that the material flow outside the flow stabilizing cylinder has a disturbance, and the filler layer can hinder the upward movement of the precipitate, thereby playing a separation role.

[0037] The working process of the device is as follows:

[0038] The caprolactam benzene extraction wastewater from the wastewater buffer tank enters the desulfurization reactor 2 to react with the Ca(OH2) solution from the Ca(OH2) delivery system 10 to generate CaSO4, and the reaction liquid is mixed with the flocculant PAC and the coagulant PAM in the first pipeline mixer 3 and the second pipeline mixer 4, respectively, and then the mixed material enters the desulfurization precipitator 5 to be separated by sedimentation, and the separated sludge is delivered to the desulfurization filter pressing system, and the upper clear liquid is delivered to the decalcification reactor 6 to be fully contacted and reacted with CO2 from the CO2 delivery system 14, and the reaction liquid is mixed with the flocculant PAC and the coagulant PAM in the third pipeline mixer 7 and the fourth pipeline mixer 8, respectively, and then the mixed material enters the decalcification precipitator 9 to be separated by sedimentation, and the separated sludge is delivered to the decalcification filter pressing system, and the upper wastewater is delivered to the wastewater delivery system.

[0039] The above-mentioned embodiments are only preferred technical solutions of the present application, and should not be regarded as a limitation of the present application. The protection scope of the present application should be based on the technical solutions recited in the claims, and the equivalent replacement solutions of the technical features recited in the claims are within the protection scope. That is, the equivalent replacement improvements within this range are also within the protection scope of the present application.

Claims

1. A caprolactam benzene extraction wastewater treatment system, characterized by: The waste water buffer tank (1) is connected with a desulfurization reactor (2), the desulfurization reactor (2) is connected with a Ca(OH)2 delivery system (10), the desulfurization reactor (2) is communicated with a desulfurization precipitator (5) in sequence through a pipeline, the desulfurization precipitator (5) is communicated with a decalcification reactor (6) through a pipeline, the decalcification reactor (6) is also connected with a CO2 delivery system (14), and the decalcification reactor (6) is communicated with a decalcification precipitator (9) in sequence through a pipeline.

2. The caprolactam benzene extraction wastewater treatment system according to claim 1, characterized in that: The desulfurization precipitator (5) is communicated with a desulfurization filter pressing system (13) through a pipeline, and the decalcification precipitator (9) is connected with a decalcification filter pressing system (15) and a waste water delivery system (16) respectively.

3. The caprolactam benzene extraction wastewater treatment system according to claim 1, characterized in that: The desulfurization reactor (2) is communicated with a first pipeline mixer (3), a second pipeline mixer (4) and the desulfurization precipitator (5) in sequence through a pipeline, and the decalcification reactor (6) is communicated with a third pipeline mixer (7), a fourth pipeline mixer (8) and the decalcification precipitator (9) in sequence through a pipeline.

4. The caprolactam benzene extraction wastewater treatment system according to claim 3, characterized in that: The first pipeline mixer (3) and the third pipeline mixer (7) are communicated with a flocculant delivery system (11) through a pipeline respectively, and the second pipeline mixer (4) and the fourth pipeline mixer (8) are communicated with a coagulant delivery system (12) through a pipeline respectively.

5. The caprolactam benzene extraction wastewater treatment system according to claim 1, characterized in that: The desulfurization reactor (2) and the decalcification reactor (6) are internally provided with stirring devices, and the waste water inlet and the Ca(OH)2 inlet of the desulfurization reactor (2) are respectively provided with distributors, and the waste water inlet and the CO2 inlet of the decalcification reactor (6) are provided with distributors.

6. The caprolactam benzene extraction wastewater treatment system according to claim 1, characterized in that: The desulfurization precipitator (5) and the decalcification precipitator (9) are internally provided with a filler support (17), the filler support (17) is provided with a filler layer (18), a flow stabilizing cylinder (19) penetrates through the filler layer (18), an outlet water groove (20) is arranged above the filler layer (18), and both ends of the flow stabilizing cylinder (19) are located below the outlet water groove (20) and the filler layer (18) respectively.

7. The caprolactam benzene extraction wastewater treatment system according to claim 6, characterized in that: The flow stabilizing cylinder (19) is in an inverted funnel shape below the filler layer (18).

8. The caprolactam benzene extraction wastewater treatment system according to claim 3, characterized in that: The communication position of the second pipeline mixer (4) and the desulfurization precipitator (5) is above the filler layer (18), and the communication position of the second pipeline mixer (4) and the desulfurization precipitator (5) is above the filler layer (18).

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