Pretreatment system applied to semi-coke wastewater

Abstract

The utility model provides a pretreatment system applied to semi-coke wastewater, which is characterized in that undissolved oil in the semi-coke wastewater is removed by using a phase separation unit, and then suspended matters in the wastewater are removed by using a filtering unit, so that the suspended matters are prevented from damaging a membrane component of an oil removal membrane unit. And finally, emulsified oil in the wastewater is removed by using the oil removal membrane unit, and the series of pretreatment steps ensure that various pollutants including insoluble oil, suspended particles and emulsified oil in the semi-coke wastewater are comprehensively and effectively treated, so that the wastewater smoothly enters a subsequent treatment stage, and the continuity and high efficiency of the whole treatment process of the semi-coke wastewater are ensured. In addition, on one hand, the back-flushing unit provides the design of mutual back-flushing regeneration of clear liquid between the filters connected in parallel without additionally introducing a back-flushing medium, on the other hand, a gas back-flushing pipeline and a steam back-flushing pipeline are additionally arranged, back-flushing gas and steam are introduced for back-flushing, the cleaning effect is optimized, and the back-flushing efficiency is improved. The service life and the operation effect of the filter are prolonged.

Description

TECHNICAL FIELD

[0001] The utility model belongs to wastewater treatment technical field, concretely relates to a kind of pretreatment system applied to semi-coke wastewater. BACKGROUND

[0002] Semi-coke wastewater is remarkable with its unique high oil content, high chemical oxygen demand (COD) and containing a certain amount of suspended solids and other characteristics.In semi-coke wastewater, oil exists in three different forms: undissolved oil, emulsified oil and dissolved oil. Among them, emulsified oil occupies a large proportion, and its special dispersion state makes it difficult to effectively remove by traditional oil removal technologies such as air flotation, flocculation sedimentation, ceramic filtration, etc. In addition, the presence of suspended solids and undissolved oil further exacerbates the difficulty of treatment, and these impurities can easily cause the oil removal equipment to be blocked, thereby affecting the stability and operating efficiency of the equipment. Therefore, for the treatment of semi-coke wastewater, a more efficient and reliable treatment equipment and process is urgently needed to ensure the thoroughness of oil removal and the long-term stable operation of the equipment. SUMMARY

[0003] To solve the problems of poor oil removal effect and easy blockage of oil removal equipment in existing semi-coke wastewater, the utility model provides a pretreatment system applied to semi-coke wastewater, which is composed of a phase separation unit, a filtration unit and an oil removal membrane unit. The phase separation unit is responsible for separating undissolved oil from semi-coke wastewater and discharging the separated oil phase out of the system. The filtration unit can effectively remove suspended substances in wastewater to prevent these substances from polluting the membrane elements in the subsequent oil removal membrane unit. Finally, the oil removal membrane unit can remove emulsified oil in wastewater. Through this series of pretreatment processes, undissolved oil, suspended solids and emulsified oil in semi-coke wastewater are fully removed. The pretreated wastewater is then sent to the next treatment stage, ensuring the continuous and stable operation of the subsequent treatment process of semi-coke wastewater. In addition, the backflush unit provided by the utility model can use the clear liquid generated by the filter unit itself to realize backflush regeneration, and the entire process does not need to introduce any backflush medium, which is efficient and energy-saving.

[0004] To achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The application discloses a pretreatment system applied to semi-coke wastewater, which comprises a phase separation unit, a filtration unit and an oil removal membrane unit.

[0006] In some embodiments, the pretreatment system further comprises a backwashing unit, which comprises a plurality of backwashing clear liquid pipes, one end of any backwashing clear liquid pipe being communicated with a clear liquid outlet of one of the filters, and the other end of the backwashing clear liquid pipe being communicated with a backwashing water inlet of another filter.

[0007] In some embodiments, the backwashing unit further comprises a gas backwashing pipeline and a steam backwashing pipeline, the filters being communicated with the gas backwashing pipeline and the steam backwashing pipeline respectively, so that a backwashing gas source and steam are introduced into the filters for flushing.

[0008] In some embodiments, the backwashing unit further comprises a residue discharging pipe arranged at the bottom of the filter, so as to discharge the impurities flushed out of the filter.

[0009] In some embodiments, the pretreatment system further comprises an emulsified oil pipeline, two ends of the emulsified oil pipeline being communicated with a concentrated liquid outlet of the oil removal membrane device and a feed inlet of the phase separation unit respectively.

[0010] In some embodiments, the phase separation device is internally provided with a coalescence section, a special plate group and a sedimentation section in sequence, a loose fiber bed is arranged in the coalescence section, and the light oil and the heavy oil in the semi-coke wastewater can be gathered and increased in size when flowing through the loose fiber bed and the special plate group; and the sedimentation section is used for separating the wastewater from the light oil and the heavy oil.

[0011] In some embodiments, the phase separation device comprises a horizontally arranged first cylinder and a vertically arranged second cylinder, the first cylinder and the second cylinder being communicated with each other, the coalescence section and the special plate group being arranged in the first cylinder, and the sedimentation section being arranged in the second cylinder.

[0012] In some embodiments, a circulating pump is arranged on the oil removal circulating pipe to provide power for conveying the thick liquid.

[0013] Compared with the prior art, the pretreatment system applied to the semi-coke wastewater has the following beneficial effects:

[0014] 1. The pretreatment system provided by the utility model is composed of a phase separation unit, a filtering unit and an oil removal membrane unit, the phase separation unit removes the insoluble oil in the semi-coke wastewater first, and discharges the oil from the system. Then, the filtering unit can remove the suspended matter in the wastewater, avoiding damage of the suspended matter to the membrane assembly in the oil removal membrane unit. Finally, the emulsified oil in the wastewater is removed through the oil removal membrane unit, and the series of pretreatment steps ensure that the insoluble oil, suspended particles and emulsified oil in the semi-coke wastewater are thoroughly treated, and the wastewater is introduced into the subsequent treatment stage after being treated through the series of pretreatment processes, so that the smoothness and efficiency of the subsequent treatment process of the semi-coke wastewater are ensured.

[0015] 2. The filtering unit provided by the utility model removes the suspended matter in the semi-coke wastewater which has not formed oily slurry, and the design effectively protects the subsequent oil removal membrane unit, prevents the membrane assembly from being damaged due to pollution of the suspended matter, and ensures stable operation and long-term efficiency of the entire wastewater treatment system.

[0016] 3. In the backflushing unit provided by the utility model, each backflushing clear liquid pipe is connected with a pair of filters, an efficient self-circulation flushing system is realized, the parallel filter is regenerated through backflushing by using the clear liquid produced by the normal working filter, the process does not need to add any flushing medium, the design of the clear liquid mutual backflushing and regeneration between the parallel filters significantly reduces resource consumption.

[0017] 4. The backflushing unit provided by the utility model is also provided with a gas backflushing pipeline and a steam backflushing pipeline, the pipelines inject backflushing gas or steam into the interior of the filter, can more deeply remove the blockage and residual impurities in the filter, ensure continuous and efficient operation of the filtering system, optimize the cleaning effect, and prolong the service life of the filter. BRIEF DESCRIPTION OF DRAWINGS

[0018] The utility model will be further explained in connection with the drawings and embodiments.

[0019] Figure 1 The utility model provides the structure schematic diagram of the pretreatment system.

[0020] The meanings of the mark symbols in the drawings are as follows:

[0021] 1 - phase separator; 2 - light oil pipe; 3 - heavy oil pipe; 4 - oil phase outlet pipe; 5 - outlet pipe; 6 - filter; 61 - filter A; 62 - filter B; 7 - clear liquid pipe; 8 - gas backflush pipe line; 9 - steam backflush pipe line; 10 - slag discharge pipe; 11 - slag discharge main pipe; 12 - oil film removal device; 13 - oil removal circulation pipe; 14 - circulation pump; 15 - emulsified oil pipe. DETAILED DESCRIPTION

[0022] The utility model is further explained in detail below in combination with the description of the drawings and specific embodiments, but the following description including embodiments is only used for the ordinary skilled in the art to which the utility model belongs to understand the principle and essence of the utility model more clearly, and does not mean to limit the utility model in any form.

[0023] As Figure 1 Indicated, the utility model provides a kind of application in semi coke wastewater's pretreatment system, including: the phase separation unit of separating out light oil and heavy oil in semi coke wastewater, the filtration unit of filtering and removing suspended solids in wastewater and the oil film removal unit of filtering and removing emulsified oil in wastewater, specific:

[0024] The phase separation unit described above includes: phase separator 1, light oil pipe 2 and heavy oil pipe 3, wherein the phase separator 1 is built-in loose fiber bed and special plate group, for separating out light oil and heavy oil in semi coke wastewater.

[0025] Light oil pipe 2 and heavy oil pipe 3 are communicated with the light oil outlet and heavy oil outlet of phase separator 1 respectively, to discharge light oil and heavy oil.

[0026] As Figure 1 Indicated, the phase separator 1 provided by the utility model includes a horizontally arranged first cylinder and a vertically arranged second cylinder, the first cylinder and the second cylinder are communicated, and the horizontally arranged first cylinder provides a wider cross-sectional area, so that semi coke wastewater can flow slowly after entering the separator, which helps the heavy phase to settle to the bottom under the action of gravity.

[0027] The horizontally arranged first cylinder is provided with a coalescing section and a special plate group, the coalescing section is filled with a loose fiber bed, and the loose fiber bed is made of modified fluorine fiber and metal wire mixed and woven, which not only has a large surface area, but also has super strong anti-pollution ability. The loose fiber bed can make the light oil and heavy oil in semi coke wastewater rebound and collide on the surface of the fiber bed to rapidly increase the diameter of oil droplets, so as to realize the rapid settling separation of light oil and heavy oil. The special plate group is stacked by special structure plates, and the light oil and heavy oil droplets increased by the loose fiber bed further rebound and collide on the surface of the special plate group, so as to further accelerate the rapid settling separation of light oil and heavy oil.

[0028] The second cylinder arranged vertically is a sedimentation section for further separation process, and the light oil outlet and the heavy oil outlet are arranged at the top and the bottom of the second cylinder respectively, so that the discharge of the light phase and the heavy phase can be controlled more conveniently, and the light phase can be discharged from the top, while the heavy phase is discharged from the bottom.

[0029] Furthermore, the phase separation unit further comprises an oil phase outlet pipe 4 in communication with the light oil pipe 2 and the heavy oil pipe 3, and the light oil pipe 2 and the heavy oil pipe 3 are discharged smoothly through the oil phase outlet pipe 4 after being collected, thereby ensuring the effective separation and discharge of the oil phase.

[0030] The phase separation unit can remove the undissolved oil, a small amount of emulsified oil and suspended matter in the coking waste water, and the oily slurry wrapped by the oily matter, reduce the possibility that the suspended matter and the undissolved mixture form the oily slurry to cause the filter unit to be unable to operate stably in the subsequent section, otherwise the oily slurry continuously pollutes the membrane element in the filter unit.

[0031] The filter unit comprises a plurality of parallel filters 6, the inlet of each filter 6 is in communication with the outlet of the phase separator 1, and the coking waste water from which the light oil and the heavy oil are removed is branched into each filter 6 to remove the suspended matter in the coking waste water.

[0032] Preferably, the number of filters 6 is 2 or more, and the number of filters and the filter cartridges filled in the filters are determined according to the processing capacity.

[0033] The oil removal membrane unit comprises an oil removal membrane device 12 and an oil removal circulation pipe 13, the inlet of the oil removal membrane device 12 is in communication with the clear liquid outlet of the filter 6 through the clear liquid pipe 7, the oil removal membrane is built in the oil removal membrane device 12, the waste water from which the suspended matter is removed is introduced into the oil removal membrane device 12 through the clear liquid pipe 7, and the emulsified oil in the waste water can be effectively removed through the high-efficiency operation of the oil removal membrane, thereby ensuring that the waste water is further purified.

[0034] Preferably, the oil removal membrane is a roll-type ultrafiltration membrane, which can remove the emulsified oil in the coking waste water and can tolerate an oil content of more than 20000 ppm.

[0035] The two ends of the oil removal circulation pipe 13 are in communication with the concentrated liquid outlet and the inlet of the oil removal membrane device 12, thereby forming a closed circulation system to perform efficient circulation oil removal treatment on the concentrated liquid discharged from the oil removal membrane device 12, and the part of the emulsified oil intercepted by the oil removal membrane is pressurized by the circulating pump 14 and then enters the oil removal membrane again, thereby ensuring the flow velocity of the membrane surface of the oil removal membrane and allowing the coking waste water to form a turbulent flow on the surface of the oil removal membrane to continuously flush the membrane surface and increase the anti-pollution ability of the oil removal membrane.

[0036] Preferably, the oil removal circulation pipe 13 is provided with a circulating pump 14 for providing conveying power for the concentrated liquid.

[0037] In some embodiments, the pretreatment system further comprises a backflushing unit, which comprises a plurality of backflushing pipes, one end of each backflushing pipe being connected to the clean liquid outlet of one of the filters 6, and the other end of each backflushing pipe being connected to the backflushing liquid inlet of another filter 6, i.e. each backflushing pipe connects two filters 6. As the filters 6 are in operation, the pressure difference of the filters 6 increases continuously, and when the pressure difference reaches a preset pressure difference threshold, a backflushing operation is performed on the filter 6, using the clean liquid generated by other filters 6 in the system.

[0038] Preferably, the backflushing cycle can be preset according to the pressure difference or the filtration time of the filter, so as to ensure that the filter can maintain a constant filtration pressure difference state, thereby optimizing the filtration performance.

[0039] Further, the backflushing unit described above further comprises a gas backflushing pipeline 8 and a steam backflushing pipeline 9, and each filter 6 is connected to the gas backflushing pipeline 8 and the steam backflushing pipeline 9. In the case that the clean liquid backflushing is not sufficient to achieve the desired cleaning effect, the system can be flexibly switched to a gas backflushing or steam backflushing mode, and a backflushing gas source or steam is injected into the filter 6 to enhance the cleaning effect. The two sets of pipelines can be independently controlled, so as to ensure that the filter 6 can be effectively and targetedly maintained under different cleaning requirements.

[0040] Further, the backflushing unit described above further comprises a slag discharge pipe 10 arranged at the bottom of the filter 6, so as to discharge the impurities flushed out of the filter 6.

[0041] Preferably, a slag discharge main pipe 11 is further included, and the slag discharge pipe 10 of each filter 6 is connected to the slag discharge main pipe 11, so that the impurities in each filter 6 can be collected and discharged from the system through the slag discharge main pipe 11.

[0042] In some embodiments, the pretreatment system further comprises an emulsified oil pipeline 15 connected to the concentrated liquid outlet of the oil removal membrane device 12 and the phase separation device 1. A part of the concentrated liquid discharged from the oil removal membrane device 12 enters the phase separation unit through the emulsified oil pipeline 15 for further separation, while the emulsified oil content of the oil removal membrane device is maintained stable.

[0043] The main reason why the returned emulsified oil can be treated by the phase separation device 1 is that: 1. The emulsified oil intercepted by the oil removal membrane enters the phase separation device 1 and is further coalesced and increased; 2. The return of the emulsified oil intercepted by the oil removal membrane increases the oil content at the inlet of the phase separation device 1, causing the oil droplets dissolved in the semi-coke wastewater to be saturated and precipitated.

[0044] In summary, the process steps of pretreating the semi-coke wastewater by using the pretreatment system described above include:

[0045] S1, After the treatment of the phase separator 1, the light oil and heavy oil in the semi-coke wastewater are separated and discharged, and then flow into each filter 6 for filtration to remove the suspended solids in the wastewater.

[0046] S2, The purified wastewater flows into the oil removal membrane device 12 through the clear liquid pipe 7, and the emulsified oil is further removed under the action of the oil removal membrane.

[0047] S3, The concentrated liquid separated by the oil removal membrane is circulated into the oil removal membrane device 12 through the oil removal circulation pipe 13 to continuously remove the oil in the concentrated liquid.

[0048] S4, The wastewater treated by the oil removal is discharged from the oil removal membrane device 12 into the next processing unit.

[0049] The specific process of step S1 is as follows: the semi-coke wastewater enters the phase separator 1 through the feed inlet of the phase separator 1, and after the treatment of the phase separator 1, the light oil and heavy oil in the semi-coke wastewater are collected into the oil phase outlet pipe 4 through the light oil pipe 2 and the heavy oil pipe 3 respectively, and then discharged from the phase separator 1. The semi-coke wastewater after oil removal from the phase separator 1 is discharged from the water outlet and enters the filtration unit through the outlet pipe 5.

[0050] Taking the case of setting two filters 6 (filter A61 and filter B62), the semi-coke wastewater in the outlet pipe 5 enters each filter A61 and filter B62 respectively, and after the treatment of the two filters 6, the suspended solids in the semi-coke wastewater are intercepted on the surface of the filter membrane, and the clear liquid that passes through the filter membrane is collected into the clear liquid main pipe through two clear liquid pipes 7 and enters the oil removal membrane unit.

[0051] In some embodiments, the pretreatment process further includes a flushing operation of the filter 6: when the differential pressure of any filter 6 is monitored to rise to a preset differential pressure threshold, the flushing program is started, for example, using the clear liquid of the filter B62 to flush the filter A61: first, the valves on the inlet pipe line and the outlet pipe 5 line (i.e. the clear liquid pipe 7) of the filter A61 to be flushed are closed, and then the clear liquid discharged from the running filter B62 is used to backflush the filter A61 through the backflush clear liquid pipe.

[0052] In this process, the deslagging valve on the deslagging pipe 10 of the filter A61 is opened to discharge the impurities flushed out.

[0053] After the completion of the flushing program, the valves closed previously are reopened to restore the normal working state of the filter A61; then, the clear liquid discharged from the filter A61 after the completion of the flushing is used to backflush the filter B62 that provides the backflush clear liquid, and the valves on the inlet pipe line and the outlet pipe 5 line of the filter B62 are closed before the process starts.

[0054] Further, the flushing operation also includes: using the gas backflush pipeline 8 and the steam backflush pipeline 9 to introduce the backflush gas source and the steam respectively to backflush and regenerate the filter 6 to be flushed. It is to be noted that when the backflush gas source and the steam backflush, the valves on the inlet pipeline and the outlet pipeline 5 of the filter 6 to be flushed also need to be closed, and the deslagging valve on the deslagging pipeline 10 needs to be opened.

[0055] The specific process of steps S2-S4 is as follows:

[0056] The clear liquid discharged by each filter 6 is collected with the concentrated liquid returned by the oil removal circulating pipeline 13, and then enters the circulating pump 14. After being pressurized by the circulating pump 14, the clear liquid enters the oil removal membrane device 12 through the inlet pipeline. After being treated by the oil removal membrane, the emulsified oil in the waste water is intercepted on the membrane concentrated liquid side, and then circulates in the system through the oil removal circulating pipeline 13. The clear liquid that passes through the oil removal membrane is the semi-coke waste water after the pretreatment, and enters the next processing unit.

[0057] Further, the oil removal membrane device 12 divides a small amount of concentrated liquid to guide to the phase separation unit through the emulsified oil pipeline 15 to continue to be treated, so as to maintain the stability of the emulsified oil content of the oil removal membrane unit.

[0058] The ideal embodiment of the utility model is inspired, through the above description, the relevant staff can certainly carry out the variety of change and the modification in the range of not deviating from the technical thought of the utility model.

[0059] The technical scope of the utility model is not limited to the content in the specification, and must be determined according to the scope of claims.

Claims

1. A pre-treatment system applied to semi-coke wastewater, characterized in that, The system comprises: a phase separation unit comprising a phase separator, a light oil pipe and a heavy oil pipe, the phase separator being used to separate light oil and heavy oil from the coking wastewater; the light oil pipe and the heavy oil pipe being in communication with the light oil outlet and the heavy oil outlet of the phase separator respectively to discharge the light oil and the heavy oil; a filtration unit comprising a plurality of filters in parallel, the inlet of the filters being in communication with the water outlet of the phase separator to filter and remove suspended solids in the coking wastewater; an oil removal membrane unit comprising an oil removal membrane device and an oil removal circulation pipe, the inlet of the oil removal membrane device being in communication with the clear liquid outlet of the filters through a clear liquid pipe, the oil removal membrane device being internally provided with an oil removal membrane; the two ends of the oil removal circulation pipe being in communication with the concentrated liquid outlet and the inlet of the oil removal membrane device to perform circulation oil removal treatment on the concentrated liquid discharged from the oil removal membrane device.

2. The pretreatment system according to claim 1, wherein the pretreatment system further comprises a backwashing unit, the backwashing unit comprises a plurality of backwashing clear liquid pipes, one end of any backwashing clear liquid pipe being in communication with the clear liquid outlet of one of the filters, the other end of the backwashing clear liquid pipe being in communication with the backwashing water inlet of another filter.

3. The pretreatment system according to claim 2, wherein the backwashing unit further comprises a gas backwashing pipe line, the filters being in communication with the gas backwashing pipe line to introduce a backwashing gas source into the filters for flushing.

4. The pretreatment system according to claim 2, wherein the backwashing unit further comprises a steam backwashing pipe line, the filters being in communication with the steam backwashing pipe line to introduce steam into the filters for flushing.

5. The pretreatment system according to any one of claims 2-4, wherein the backwashing unit further comprises a residue discharge pipe arranged at the bottom of the filters to discharge impurities flushed out of the filters.

6. The pretreatment system according to claim 1, further comprising an emulsified oil pipe line, the two ends of the emulsified oil pipe line being in communication with the concentrated liquid outlet of the oil removal membrane device and the feed inlet of the phase separator respectively.

7. The pretreatment system according to claim 1, wherein the phase separator is internally provided with a coalescence section, a special plate group and a sedimentation section in sequence, the coalescence section is internally provided with a loose fiber bed, and the oil droplets in the coking wastewater can be gathered and increased when flowing through the loose fiber bed and the special plate group; the sedimentation section is used for separating the wastewater from the light oil and the heavy oil.

8. The pretreatment system according to claim 7, wherein the phase separator comprises a horizontally arranged first cylinder and a vertically arranged second cylinder, the first cylinder and the second cylinder being in communication, the coalescence section and the special plate group being arranged in the first cylinder, and the sedimentation section being arranged in the second cylinder.

9. The pretreatment system according to claim 1, wherein a circulation pump is arranged on the oil removal circulation pipe to provide conveying power for the concentrated liquid. ​

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