Sulfur-containing sewage treatment method

Abstract

The invention relates to a sulfur-containing sewage treatment method, and belongs to the technical field of water treatment. The sulfur-containing sewage treatment method provided by the invention comprises the following steps: (1) dividing sulfur-containing sewage into high-salt sulfur-containing sewage and low-salt sulfur-containing sewage; the conductivity of the high-salt sulfur-containing sewage is greater than 6000 [mu] s / cm; the conductivity of the low-salt sulfur-containing sewage is less than or equal to 6000 [mu] s / cm; (2) respectively conveying the high-salt sulfur-containing sewage and the low-salt sulfur-containing sewage classified in the step (1) into different sewage steam stripping devices for treatment; and (3) conveying purified water generated after treatment in the step (2) to a sewage treatment device for treatment. According to the method, the salt content of the sulfur-containing sewage generated by the oil refining device is analyzed, the sulfur-containing sewage with different salt contents is respectively treated, and the high-low-salt sulfur-containing sewage quality-divided treatment test is carried out, so that the high-low-salt purified water is discharged, treated and recycled in a quality-divided manner.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a method for treating sulfur-containing wastewater. Background Art

[0002] In existing oil refineries, when processing sulfur-containing crude oil, atmospheric and vacuum, catalytic cracking, delayed coking, hydrofining and other devices will discharge a large amount of acidic water (sulfur-containing wastewater). After acidic water stripping pretreatment, these sulfur-containing wastewaters are reinjected into the device for water injection and graded utilization or discharged into the refinery wastewater treatment device for treatment, which is the main source of wastewater for refinery wastewater treatment devices.

[0003] At present, in the design and actual operation of sour water stripping units, most of them only consider the removal of pollutants such as hydrogen sulfide, ammonia, nitrogen, oil, and phenol, without reasonable and detailed separation and overall treatment of their salt content, resulting in unreasonable graded utilization of purified water in sour water stripping units, high wastewater discharge and low wastewater reuse rate.

[0004] Therefore, it is of great significance to provide a method for treating sulfur-containing wastewater that can effectively reduce wastewater discharge and increase wastewater reuse rate. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide a method for treating sulfur-containing wastewater.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for treating sulfur-containing wastewater comprises the following steps:

[0008] (1) dividing the sulfur-containing wastewater into high-salt sulfur-containing wastewater and low-salt sulfur-containing wastewater; the conductivity of the high-salt sulfur-containing wastewater is greater than 6000 μs / cm; the conductivity of the low-salt sulfur-containing wastewater is less than or equal to 6000 μs / cm;

[0009] (2) transporting the high-salt sulfur-containing wastewater and the low-salt sulfur-containing wastewater classified in step (1) to different wastewater stripping devices for treatment;

[0010] (3) The purified water produced after the treatment in step (2) is transported to a sewage treatment plant for treatment.

[0011] The present invention analyzes the salt content of sulfur-containing wastewater generated by the oil refining device, treats sulfur-containing wastewater with different salt contents separately, and conducts a high- and low-salt sulfur-containing wastewater quality separation treatment test to demonstrate the feasibility of implementing quality separation treatment and discharging low-salt purified water into the refinery wastewater treatment and then reusing it as circulating water. After that, through process modification, the high- and low-salt sulfur-containing wastewater quality separation treatment is applied to actual production, realizing the quality separation discharge, treatment and reuse of high- and low-salt purified water. The sulfur-containing wastewater treatment method of the present invention realizes the quality separation discharge and treatment of high- and low-salt sulfur-containing wastewater, and the water quality of the stripping purified water and the high- and low-concentration wastewater series of the refinery meets the design and specification index requirements, the high-concentration wastewater discharge reduction is 30.3%, and the reuse water volume is increased by 16.1%; the key technical indicators such as the oil refinery per ton of oil discharge and the refinery wastewater reuse rate are significantly improved compared with those before the quality separation treatment; the annual cost saving is estimated to be 3.832 million yuan, of which the water intake cost is saved by 2.65% and the wastewater treatment cost is saved by 12.5%.

[0012] Preferably, in step (1), the sulfur-containing wastewater is sulfur-containing wastewater generated by an oil refinery.

[0013] As a preferred embodiment of the method for treating sulfur-containing wastewater of the present invention, in the step (1), the high-salt sulfur-containing wastewater includes at least one of sulfur-containing wastewater generated by a coking unit and sulfur-containing wastewater generated by a coking gasoline hydrogenation unit.

[0014] As a preferred embodiment of the method for treating sulfur-containing wastewater of the present invention, in the step (1), the low-salt sulfur-containing wastewater includes at least one of sulfur-containing wastewater produced by a catalytic device and sulfur-containing wastewater produced by a distillation device.

[0015] As a preferred embodiment of the method for treating sulfur-containing wastewater of the present invention, in the step (2), the wastewater stripping device uses a single-tower atmospheric pressure stripping process to treat the wastewater.

[0016] As a preferred embodiment of the method for treating sulfur-containing wastewater of the present invention, the specific operation of step (3) is to transport the purified water produced after the treatment in step (2) to the corresponding sewage treatment devices according to the salt content, the low-salt purified water is treated by the low-concentration sewage treatment system and then reused in the circulating water device, and the high-salt purified water is treated by the high-concentration sewage treatment system and then discharged.

[0017] Preferably, the conductivity of the low-salt purified water is ≤1200 μs / cm, and the conductivity of the high-salt purified water is >1200 μs / cm.

[0018] Modern petrochemical enterprises generally use the principle of separate treatment of pollutants to set up high-concentration wastewater treatment systems and low-concentration wastewater treatment systems. The low-concentration wastewater treatment system treats wastewater with low pollutant concentration and low salt content, and after treatment, it meets the water quality standards for reused water and is reused; the high-concentration wastewater treatment system treats wastewater with high pollutant concentration and high salt content, and after treatment, it meets the discharge index requirements for discharge, or is further desalted and recycled. The reference standard is: "Water Quality Control Index for Refinery Wastewater Reuse" Q / SH 0104-2007, and the water quality index conductivity of wastewater reused for circulating cooling water is ≤1200μs / cm.

[0019] Preferably, in step (3), the low-concentration sewage treatment system includes at least one primary biochemical treatment unit.

[0020] Preferably, in step (3), the high-concentration sewage treatment system includes at least one primary biochemical treatment unit, and the biochemical treatment unit is simultaneously subjected to salt tolerance acclimation.

[0021] The general process setting of low-concentration sewage treatment system is relatively simple, and it can be equipped with traditional one-stage or two-stage biochemical treatment units. The high-concentration sewage treatment system, due to the high concentration of pollutants and salt content, generally has a relatively complex and long process setting, and is equipped with multi-stage biochemical units. At the same time, the biochemical system needs to be acclimated to salt tolerance in order to achieve stable operation. Preferably, in the step (3), for the wastewater stripping purified water with different pollutant concentrations, different sampling processes need to be considered, and the treatment can be carried out with reference to the "Petrochemical Wastewater Treatment Design Specification" GB50747, "Sewage Filtration Treatment Engineering Technical Specification" HJ 2008, "Membrane Biological Wastewater Treatment Engineering Technical Specification" HJ 2010, "Biological Filter Wastewater Treatment Engineering Technical Specification" HJ 2014, "Internal Circulation Aerobic Biological Fluidized Bed Wastewater Treatment Engineering Technical Specification" HJ 2021, "Anaerobic-Anoxic-Aerobic Activated Sludge Wastewater Treatment Engineering Technical Specification" HJ 576, "Sequencing Batch Activated Sludge Wastewater Treatment Engineering Technical Specification" HJ 577, "Oxidation Ditch Activated Sludge Wastewater Treatment Engineering Technical Specification" HJ 578 and other specifications.

[0022] The present invention has the following beneficial effects: the sulfur-containing wastewater treatment method of the present invention performs quality separation treatment on the sulfur-containing wastewater generated in the oil refinery and then reuses it, carries out quality separation treatment tests of high- and low-salt sulfur-containing wastewater and applies it to actual production, which is of great significance to increasing the amount of reused water, reuse rate and water saving and emission reduction of the enterprise. The present invention demonstrates the feasibility of implementing quality separation treatment and then discharging low-salt purified water into the low-concentration series of refinery wastewater for reuse by carrying out quality separation treatment by carrying out quality separation treatment of high- and low-salt sulfur-containing wastewater. The quality separation treatment of high- and low-salt sulfur-containing wastewater is applied to actual production, and the quality separation discharge, treatment and reuse of high- and low-salt purified water are realized. After the quality separation treatment is applied, the water quality of the stripping purified water and the effluent of the high- and low-concentration wastewater series of the refinery meet the design and specification index requirements, the high-concentration wastewater is reduced by 30.3%, and the amount of reused water is increased by 16.1%; the key technical indicators such as the oil refinery per ton of oil drainage and the refinery wastewater reuse rate are significantly improved compared with those before the quality separation treatment; the annual cost saving is estimated to be 3.832 million yuan, which has good economic benefits. DETAILED DESCRIPTION

[0023] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] Unless otherwise specified, the experimental methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0025] Example 1

[0026] Guangzhou Petrochemical Company of China Petroleum & Chemical Corporation (hereinafter referred to as Guangzhou Petrochemical) has a total of 4 sour water stripping units, which respectively treat sulfur-containing wastewater produced by 22 units such as distillation, catalysis, coking, and hydrogenation. The total design capacity of the 4 sour water stripping units is 380t / h, all of which adopt single-tower atmospheric pressure stripping process. The treated purified water is sent to the hydrogenation unit for reinjection, partially discharged into the refinery low-concentration wastewater treatment system for treatment and reuse, sent to the distillation electric desalination for reinjection and then discharged into the refinery high-concentration wastewater treatment system for treatment, and directly discharged into the refinery high-concentration wastewater series for treatment and then meet the discharge standards, as shown in Table 1.

[0027] Table 1 Current status of acidic water stripping

[0028]

[0029] In order to achieve the treatment of high-salinity and low-salinity sulfur-containing wastewater by quality, this embodiment investigates and analyzes the composition of wastewater stripping V and heavy catalyst and diesel reforming sulfur-containing wastewater, and classifies them according to salt content indicators. Among them, coking II, coking III, coke steam, heavy catalyst, etc. are classified as high-salinity sulfur-containing wastewater; distillation I, distillation III, light catalyst, reforming I, dissolution, etc. are classified as low-salinity sulfur-containing wastewater, as shown in Table 2.

[0030] Table 2 Classification of salt content of sulfur-containing wastewater

[0031]

[0032] The test plan makes full use of the operating sewage stripping units 2 and 5 and the out-of-service sewage stripping unit 4 as well as their raw water tank capacities to conduct a test on the quality-differentiated treatment of high-salinity and low-sulfur sewage. The sewage stripping unit 5 is used to treat low-salinity and sulfur-containing sewage, and the high-salinity and sulfur-containing sewage is sent to the sewage stripping unit 2 for treatment or to the raw water tank of the sewage stripping unit 4 for storage. This is to test whether the purified water quality indicators of the sewage stripping unit 5, when treating low-salinity and sulfur-containing sewage alone, can meet the requirements for the low-concentration series treatment of refinery sewage.

[0033] In order to shorten the replacement time of high-salt sulfur-containing wastewater in the raw water tank of the stripping unit 5, the high-salt sulfur-containing wastewater is improved in the wastewater stripping units 2 and 4, and the wastewater stripping unit 5 uses a single raw material tank for production. The hot feed temperature of the stripping unit 5 is controlled at 142℃~146℃. To ensure the normal production of the stripping tower, the feed rate is controlled at about 116t / h, and a closed-loop circulation of part of the purified water is maintained. Other key parameter controls are consistent with normal operation. The top pressure of the stripping tower is controlled at 0.48MPa~0.5MPa, the bottom temperature is controlled at 162℃~164℃, the side line extraction valve position is controlled at 20%~20.5%, and the temperature of the first layer of the tower plate in the stripping section of the stripping tower is controlled at 105℃~125℃.

[0034] Test process

[0035] The test of treating low-salt sulfur-containing wastewater separately in sewage stripping unit 5 started on January 20, 2022 and ended on January 24, for a total of 96 hours. During the test, sewage stripping unit 5 treated low-salt sulfur-containing wastewater separately, mainly low-salt sulfur-containing wastewater from distillation unit 3, distillation unit 1, reforming unit 1, light catalyst, dissolution stripping, diesel reforming and 70,000 t sulfur; the heavy catalyst raw water in high-salt sulfur-containing wastewater was sent to stripping unit 2, and the rest of the high-salt sulfur-containing wastewater was sent to stripping unit 4. The specific water volume is shown in Table 3.

[0036] Table 3 Water content of stripping during the test period

[0037]

[0038] During the test period, the fresh raw material low-salt sulfur-containing wastewater was 92t / h. Due to the low water load, the closed-loop circulation was 10t / h, the tower load was 116t / h, and the total amount of purified water sent out was 90t / h.

[0039] Test data

[0040] The test started on January 20th. According to the analysis data, the replacement was basically completed at 17:00 on the 22nd. The analysis results from the 22nd to the 24th were used as the main data basis for this test, as shown in Tables 4 and 5.

[0041] Table 4 Comparison of analysis data of main pollutants in purified water before and after the test

[0042]

[0043] Table 5 Comparison of analysis data of main salt content indicators of purified water before and after the test

[0044] Sulfate Iron content Total Alkalinity Chloride ion Conductivity hardness index ≤300 ≤0.5 50-300 ≤200 ≤1000 50-300 Before the test 580 0.54 313.5 103.5 2030 25.5 Late stage 40 0.39 250 3 450 19.8

[0045] It can be seen from the test data in Table 4 and Table 5 that the salt content indicators of the purified water quality analysis results after the quality separation treatment test all meet the requirements of the low-concentration series of refinery wastewater discharge. Except for sulfide, the other data of the main pollutants do not meet the import indicators of the low-concentration series of refinery wastewater. However, considering the large low-concentration import flow rate and low pollutant load, the discharge volume of the stripping five purified water is small, and the contribution value of each indicator is low. The discharge of low-salt sulfur-containing wastewater to low concentration needs further calculation.

[0046] Calculation of water quality by quality

[0047] According to the test data and the inlet analysis data of the high- and low-concentration wastewater treatment system of the refinery wastewater, the pollutant concentrations at the inlet of the high- and low-concentration wastewater treatment system after the separation treatment are calculated according to the working conditions of distillation three injections of steam stripping and four purification water discharge to the high-concentration wastewater treatment system, distillation one injection of steam stripping and five purification water discharge to the high-concentration wastewater treatment system, and the remaining discharge to the low-concentration wastewater treatment system. The details are shown in Table 6.

[0048] Table 6 Comparison of pollutant concentrations in the inlet of refinery wastewater high and low concentration treatment systems after sulfur-containing wastewater separation treatment

[0049]

[0050] From the measurement, the water volume of the high-concentration sewage treatment system has decreased significantly, but the COD and total nitrogen data of the high-concentration sewage treatment system of the refinery sewage have increased significantly, but from the perspective of the total amount of pollutants, it is lower than the current working level. The water volume of the low-concentration sewage treatment system of the refinery sewage has increased, and the pollutant concentration has increased, but it is within the indicator range.

[0051] Conclusion

[0052] The sulfur-containing wastewater treatment method of this embodiment treats low-salt sulfur-containing wastewater separately in the wastewater stripping step 5, which achieves good separation treatment of high-salt and low-salt raw sulfur-containing wastewater. The test analysis data can truly reflect the water quality of high-salt and low-salt sulfur-containing wastewater after separation treatment, and has strong representativeness and guidance. After separation treatment, the salt concentration index of the wastewater stripping step 5 purified water fully meets the index of the low-concentration series of refined wastewater discharge. The main pollutants are calculated by mixing with the existing low-concentration series of refined wastewater, meeting the import index requirements of the low-concentration series of refined wastewater; the COD and total nitrogen data of the imported high-concentration series of refined wastewater increase, but the total amount of pollutants calculated is lower than the existing working condition level, which can be further applied in practice.

[0053] Example 2

[0054] According to the conclusion of the high- and low-salt sulfur-containing wastewater quality-separation treatment test in Example 1, it is determined that the high- and low-salt sulfur-containing wastewater quality-separation treatment method is applied in the Guangzhou Petrochemical Refinery Area. That is, the raw water of the original sewage stripping five is divided into two parts: high-salt sulfur-containing wastewater and low-salt sulfur-containing wastewater. The low-salt sulfur-containing wastewater of distillation one, distillation three, reforming one, light catalyst, dissolution stripping, diesel reforming, and 70,000 sulfur production is treated by sewage stripping five, and the purified water part is sent to distillation one electric desalination and then discharged into the oil refinery high-concentration wastewater treatment system for treatment and then discharged, and the rest is discharged into the oil refinery low-concentration wastewater treatment system in steps for treatment and then reused as oil refinery circulating water; coking two, coking three, coke steam hydrogenation, heavy catalyst, S zorb and other high-salt sulfur-containing wastewater are treated by sewage stripping four, and the purified water is sent to distillation one for re-injection and then discharged into the oil refinery wastewater high-concentration wastewater treatment system and then discharged in compliance with the standards; the sewage stripping two device is shut down.

[0055] The application of separate treatment will be implemented from March 21, 2022. The system adjustment will go through the stages of steam stripping replacement, sewage acclimatization and three discharge switching, and will be completed on April 15, a total of 25 days. See Table 7 for details.

[0056] Table 7 Implementation time nodes for high- and low-salt sulfur-containing wastewater separation treatment

[0057]

[0058] On March 28, April 8, and April 15, the water from the fifth purification of the wastewater stripping process was gradually increased and discharged into the low-concentration treatment system for oil refinery wastewater. Except for the water sent to the first distillation for injection, all the water from the fifth purification of the stripping process was discharged to the low-concentration treatment system for oil wastewater and then reused in the oil refinery circulating water system.

[0059] Every time the sewage stripping five-purification water is switched to discharge into a low-concentration sewage treatment system, the analysis data such as A / O of the biochemical system of the low-concentration sewage treatment system and COD and ammonia nitrogen of the contact oxidation effluent will fluctuate slightly, but after domestication and adaptation, they can return to normal levels in a short time.

[0060] Water quality effect of water quality treatment

[0061] After the implementation of the application of quality-differentiated treatment, the water quality of sewage stripping IV, sewage stripping V, distillation and electric desalination drainage, and high and low concentration series of oil refinery sewage has reached the expected effect. See Table 8 and Table 9 for details.

[0062] Table 8 Comparison of water quality analysis data of purified water and electric desalination drainage before and after the implementation of quality treatment application

[0063]

[0064] As can be seen from Table 8, after the implementation of the separation treatment, the pollutant concentration and conductivity index of the stripping five purified water decreased significantly compared with before separation, and the average conductivity dropped to 598μs / cm, meeting the requirements of the low-concentration series of refinery wastewater discharge. The water quality analysis data of distillation electro-desorption drainage and stripping four purified water meet the requirements of the high-concentration series of refinery wastewater discharge.

[0065] Table 9 Comparison of water quality analysis data of refinery wastewater before and after the implementation of separation treatment

[0066]

[0067] As can be seen from Table 9, after the implementation of the application of quality separation treatment, the water volume of the high-concentration series of refinery wastewater decreased by about 50t / h, and the emission reduction reached 30.3%; the concentration index of the imported pollutants in the high-concentration series decreased, and the conductivity index increased slightly. The water volume of the low-concentration series of refinery wastewater increased by about 50t / h, the amount of recycled water increased by 16.1%, the concentration index of pollutants such as COD and ammonia nitrogen in the low-concentration series increased, and the conductivity index remained the same. After the implementation of the application of quality separation treatment, the high and low concentration imported water quality indicators of refinery wastewater met the design index requirements.

[0068] Technical indicators and economic benefits

[0069] The key technical indicators and economic benefits of high-salinity and low-sulfur wastewater treatment before and after the implementation of the application of separate treatment, such as the per-ton oil wastewater and the oil refinery wastewater reuse rate, were compared and calculated. See Table 10 and Table 11 for details.

[0070] Table 10 Comparison of key technical indicators before and after the application of quality control

[0071]

[0072] As can be seen from Table 10, after the completion of the separation treatment on April 15, the refinery wastewater index per ton of oil was 0.13t / t, and the refinery wastewater reuse rate index was 66.89%, both of which were significantly improved compared with before the separation treatment.

[0073] Table 11 Benefit calculation after application of quality treatment

[0074]

[0075] As can be seen from Table 11, based on the full cost of sewage treatment of low concentration 3.42 yuan / ton, high concentration 10.27 yuan / ton and the full cost of fresh water production 1.9 yuan / ton, after the implementation of high- and low-salt sulfur-containing sewage separation treatment, the annual benefit increased by 3.832 million yuan due to the reduction of high-concentration sewage load and the increase of low-concentration and recycled water.

[0076] Comparative Example 1

[0077] The Guangzhou Petrochemical Company of China Petrochemical Corporation (hereinafter referred to as Guangzhou Petrochemical) has a total of 4 sets of acidic water stripping units, which respectively treat the sulfur-containing wastewater generated by 22 sets of units such as distillation, catalysis, coking, and hydrogenation. The total design capacity of the 4 sets of acidic water stripping units is 380t / h. All of them adopt a single-tower atmospheric pressure stripping process. The treated purified water is sent to the hydrogenation unit for reinjection, partially discharged into the refinery low-concentration wastewater series for treatment and reuse, sent to the distillation electric desalination for reinjection and then discharged into the refinery high-salt wastewater series for treatment, and directly discharged into the refinery high-concentration wastewater series for treatment and then discharged in compliance with the standards. After recent years of optimization and water-saving and emission reduction research, the actual generation of refinery sulfur-containing wastewater is 196t / h, and the graded reuse rate of sulfur-containing wastewater is 63.47%. See Table 12 for details.

[0078] Table 12 Current status of comprehensive utilization of sulfur-containing wastewater

[0079]

[0080] Current Status of Refinery Wastewater Treatment and Reuse

[0081] The refinery wastewater treatment device is divided into two series: high-concentration wastewater treatment system and low-concentration wastewater treatment system. The designed treatment load of each series is 400t / h. The low-concentration wastewater treatment system mainly treats production wastewater with low salt content and low pollutant concentration, and the actual treatment load is about 300-350t / h; the high-concentration wastewater treatment system mainly treats production wastewater with high salt content and high pollutant concentration. This part of wastewater mainly includes desulfurization purified water, distillation and electric desalination drainage, crude oil and intermediate raw material tank dehydration, alkali residue wastewater, flue gas desulfurization wastewater, circulating water, and chemical water neutralization wastewater. The specific situation is shown in Table 13.

[0082] Table 13 Composition of high-concentration series of refinery wastewater

[0083] High concentration sewage composition Water volume, t / h Proportion, % Desulfurized purified water → distilled electric desalination wastewater 60 25.1 Desulfurization water purification 70 29.3 Dehydration of crude oil and intermediate raw material tanks 11 4.6 Flue gas wastewater 26 10.9 Alkali residue wastewater 2 0.8 Circulating water drainage 30 12.6 Chemical water and wastewater 15 6.3 Internal drainage of high concentration sewage 25 10.5

[0084] It can be seen from Table 13 that desulfurization purified water and distillation and electrical desalination wastewater are the main components of the high-concentration refinery wastewater treatment system, accounting for 29.3% and 25.1% respectively, and a total of 54.4%.

[0085] In recent years, through the work of water conservation and emission reduction, the discharge of high-concentration sewage has been reduced year by year, and the sewage reuse rate has been increased year by year. However, there are bottlenecks in further reducing emissions and increasing the reuse rate. See Table 14 for details.

[0086] Table 14 Discharge and reuse of refinery wastewater

[0087] time Refinery wastewater discharge, t / h Refinery wastewater reuse, t / h Refinery wastewater reuse rate, % 2017 304 257 45.79 2018 264 305 53.66 2019 240 347 59.13 2020 211 307 59.32 2021 225 311 58.02

[0088] From the above data, it can be seen that if the sulfur-containing wastewater at the source is not classified and treated separately according to the salt content, there will be problems such as high wastewater discharge and low wastewater reuse rate.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for treating sulfur-containing wastewater, characterized in that: The following steps are involved: (1) dividing the sulfur-containing wastewater into high-salt sulfur-containing wastewater and low-salt sulfur-containing wastewater; the conductivity of the high-salt sulfur-containing wastewater is greater than 6000 μs / cm; the conductivity of the low-salt sulfur-containing wastewater is less than or equal to 6000 μs / cm; (2) transporting the high-salt sulfur-containing wastewater and the low-salt sulfur-containing wastewater classified in step (1) to different wastewater stripping devices for treatment; (3) The purified water produced after the treatment in step (2) is transported to a sewage treatment plant for treatment.

2. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (1), the sulfur-containing wastewater is sulfur-containing wastewater generated by an oil refining device.

3. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (1), the high-salt sulfur-containing wastewater includes at least one of the sulfur-containing wastewater produced by a coking unit and the sulfur-containing wastewater produced by a coking gasoline hydrogenation unit.

4. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (1), the low-salt sulfur-containing wastewater includes at least one of the sulfur-containing wastewater produced by a catalytic device and the sulfur-containing wastewater produced by a distillation device.

5. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (2), the sewage stripping device uses a single-tower atmospheric pressure stripping process to treat the sewage.

6. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: The specific operation of step (3) is as follows: the purified water produced after the treatment in step (2) is transported to the corresponding sewage treatment device according to the salt content, the low-salt purified water is treated by the low-concentration sewage treatment system and then reused in the circulating water device, and the high-salt purified water is treated by the high-concentration sewage treatment system and then discharged.

7. The method for treating sulfur-containing wastewater according to claim 6, characterized in that: The conductivity of the low-salt purified water is ≤1200 μs / cm, and the conductivity of the high-salt purified water is >1200 μs / cm.

8. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (3), the low-concentration sewage treatment system includes at least one primary biochemical treatment unit.

9. The method for treating sulfur-containing wastewater according to claim 1, characterized in that: In the step (3), the high-concentration sewage treatment system includes at least one primary biochemical treatment unit, and the biochemical treatment unit is simultaneously subjected to salt tolerance acclimation.

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