CN116081840A

CN116081840A - Method for treating oil refining alkaline residue waste liquid by homogeneous catalysis wet oxidation

Info

Publication number: CN116081840A
Application number: CN202111278926.3A
Authority: CN
Inventors: 马和旭; 程梦婷; 周彤; 程晓东; 王鹏
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2021-10-31
Filing date: 2021-10-31
Publication date: 2023-05-09

Abstract

The invention discloses a method for treating oil refining alkaline residue waste liquid by homogeneous catalysis wet oxidation, which comprises a wet oxidation section and an advanced treatment section, wherein the oil refining alkaline residue waste liquid firstly enters an adjusting tank, is mixed with single-membrane electrodialysis mother liquor and a homogeneous catalyst, is added with acid to adjust pH, enters a wet oxidation reactor after heat exchange and temperature rise, is cooled by a cooler after heat exchange of effluent, is subjected to nanofiltration treatment, and is subjected to single-membrane electrodialysis treatment, the single-membrane electrodialysis mother liquor flows back to the adjusting tank, nanofiltration product water enters the advanced treatment section, and single-membrane electrodialysis anion liquid enters the advanced treatment section; the nanofiltration water and the single-membrane electrodialysis anion liquid sequentially pass through a neutralization tank, a primary biochemical treatment, an ozone catalytic oxidation and a secondary biochemical treatment of the advanced treatment section, and enter a water outlet monitoring tank. Aiming at the alkali residue wastewater difficult to treat by refining enterprises, the invention adopts the treatment process with homogeneous catalysis wet oxidation as a core, fully exerts the characteristics of high catalytic activity and high treatment efficiency of homogeneous catalysis wet oxidation, and greatly improves the treatment capacity of wet oxidation.

Description

Method for treating oil refining alkaline residue waste liquid by homogeneous catalysis wet oxidation

Technical Field

The invention relates to a treatment method of oil refining alkaline residue waste liquid, in particular to a method for treating oil refining alkaline residue waste liquid by utilizing homogeneous catalysis wet oxidation, belonging to the technical field of wastewater treatment.

Background

The alkaline residue waste water generated in the petroleum refining process contains a large amount of neutral oil, organic acid, volatile phenol, sulfide and other toxic and harmful substances, the waste water is black brown and has malodorous smell, and the treatment difficulty is extremely high, so that the waste water is a difficult problem which puzzles oil refining enterprises.

The alkaline residue wastewater needs to be pretreated to enter a biochemical system, and advanced oxidation is a common pretreatment method, which can change refractory and high-toxicity macromolecular organic matters into degradable and low-toxicity micromolecular organic matters and even inorganic matters. The advanced oxidation method commonly comprises ozone catalytic oxidation, electrocatalytic oxidation, photocatalysis, fenton oxidation, wet oxidation and the like, wherein the electrocatalytic oxidation and the photocatalysis are still limited by high treatment cost at present, the industrial application is difficult, the Fenton oxidation has the problems of complex operation, unstable hydrogen peroxide, iron ion loss and the like, the ozone catalytic oxidation is limited in application along with the control of ozone pollutants by China, and the treatment cost is high and is limited to the terminal deep treatment.

At present, the most mainstream method of oil refining alkaline residue wastewater is a wet oxidation method, which operates under the conditions of high temperature (120-320 ℃) and high pressure (0.5-20 MPa), and uses gaseous oxygen as an oxidant to oxidatively decompose organic matters in water into small molecular organic matters or inorganic matters, and has the characteristics of no secondary pollution and low treatment cost. Then, the traditional wet oxidation needs higher temperature and pressure and relatively longer residence time, has high requirements on equipment materials and one-time investment, can only be used as pretreatment, and the effluent has higher COD.

In order to reduce the temperature and pressure required for the reaction and to improve the treatment effect, wet catalytic oxygen treatment technology (Catalytic wet air oxidation, abbreviated as cwhao) has become a hot point of research in recent years. CN201510274988.5 discloses a catalyst for catalytic wet oxidation of refractory organic wastewater, which is a "noble metal-transition metal-rare earth" composite catalyst, and the main component of carrier FSC is alumina; CN201410340574.3 discloses a catalyst for catalytic wet oxidation treatment and a preparation method thereof, wherein noble metal-non-noble metal nano alloy is used as an active ingredient, and activated carbon is used as a carrier; CN201510661575.2 discloses a heterogeneous wet oxidation catalyst, the components comprising a composite oxide support and a small amount of precious metals; CN201310621017.4 discloses a method for preparing a catalytic wet oxidation catalyst carrier, which takes active carbon as a core and amorphous silica-alumina as a shell.

The above patents all use heterogeneous catalytic wet oxidation, which has advantages in terms of separation recovery of catalyst and metal loss, but are not necessarily applicable to existing wet oxidation processes. The paper "alkali residue moderating wet oxidation+SBR processing technology industrial application" (2011) discloses a process for moderating alkali residue moderating wet oxidation of petrochemical institute, which is popularized and applied in 28 refining enterprises and has strong representativeness. The wet oxidation reactor is a bubbling flow internal circulation reactor with an inner cylinder, if a heterogeneous catalyst is adopted in the reactor, the gas-liquid circulation of the reactor can be seriously influenced, even the reactor and a pipeline are blocked, if a fixed bed method is adopted, larger air resistance can be brought, the gas-liquid circulation is more unfavorable, and the reaction rate can be greatly reduced.

Homogeneous catalysis has no internal and external diffusion effect, high dispersivity and higher catalysis efficiency than heterogeneous catalysis, and the catalyst preparation is much simpler than heterogeneous catalyst, but the problem of the application of homogeneous catalysis to wet oxidation is that the metal catalyst is lost. At present, less research is conducted in the direction, CN201210225873.3 provides a method for treating industrial wastewater by homogeneous catalysis wet oxidation, a ring gear filler is arranged in a fixed bed reactor, and an iron-based catalyst is adopted as a homogeneous catalyst, but the patent does not mention the loss of the catalyst and the corresponding solution; CN201210350157.8 provides a catalytic wet oxidation pretreatment method for glyphosate production wastewater, a multicomponent homogeneous catalyst is added, the catalyst is a soluble transition metal mixed salt, and the patent also does not mention the problem of catalyst loss.

Disclosure of Invention

Aiming at the defects, the invention provides a treatment method of oil refining alkaline residue waste liquid, which can realize the efficient treatment of the oil refining alkaline residue waste liquid by utilizing the process combination of homogeneous catalysis wet oxidation, membrane technology, special salt tolerant bacteria and the like, and simultaneously solves the problem of catalyst loss in the homogeneous catalysis process, thereby realizing the recycling of the catalyst.

In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:

the homogeneous catalysis wet oxidation treatment process of oil refining alkali slag waste liquid includes wet oxidation section and advanced treatment section;

the wet oxidation section comprises a regulating tank, a heat exchange unit, a wet oxidation reactor, a cooler, nanofiltration and single-membrane electrodialysis; the oil refining alkaline residue waste liquid firstly enters an adjusting tank, is mixed with a single-membrane electrodialysis mother solution and a homogeneous catalyst, is added with acid to adjust pH, enters a heat exchange unit, and enters a wet oxidation reactor after heat exchange and temperature rise; the effluent of the wet oxidation reactor is cooled by a cooler after heat exchange by a heat exchange unit, and enters nanofiltration for treatment, wherein nanofiltration concentrated water is treated by single-membrane electrodialysis, the single-membrane electrodialysis mother liquor flows back to an adjusting tank, and nanofiltration product water enters a deep treatment section; the single-membrane electrodialysis anion solution enters a deep treatment section;

the advanced treatment section sequentially comprises a neutralization pond, a primary biochemical treatment, an ozone catalytic oxidation, a secondary biochemical treatment and a water outlet monitoring pond; the nanofiltration water yield and the single-membrane electrodialysis anion liquid enter a neutralization tank and then enter a primary biochemical treatment, wherein the primary biochemical treatment adopts salt-tolerant bacteria GXNYJ-DL-1 to treat wastewater; carrying out ozone catalytic oxidation on the treated wastewater to further decompose organic matters which are difficult to treat, and then adopting secondary biochemical treatment again, wherein the secondary biochemical treatment also adopts salt-tolerant bacteria GXNYJ-DL-1 to further remove the organic matters in the wastewater, and finally leading the effluent to enter an effluent monitoring tank;

the salt-tolerant bacterium GXNYJ-DL-1%Halomonasnigrificans) The strain is preserved in China general microbiological culture Collection center (CGMCC) with the preservation number of CGMCC No. 20350 in the year 7 and 13 of 2020.

Further, adding acid into the regulating tank to regulate the pH value to 2-6; the acid is hydrochloric acid or sulfuric acid, preferably hydrochloric acid.

Further, the heat exchange unit consists of a plurality of heat exchangers, exchanges heat between the effluent of the wet oxidation reactor and the effluent of the regulating tank, runs the tube pass of the effluent of the wet oxidation reactor, runs the shell pass of the effluent of the regulating tank, and after multiple heat exchanges, the temperature of the effluent of the regulating tank is increased to 130-160 ℃, and the temperature of the effluent of the wet oxidation reactor is reduced to 50-75 ℃.

Further, the homogeneous catalyst is a noble metal and transition metal compound catalyst; the noble metal is one or more of platinum, palladium, rhodium, silver and ruthenium, the transition metal is one or more of copper, iron, manganese, zinc and nickel, preferably a palladium copper or rhodium copper composite catalyst, and the mass percentage of the noble metal in the homogeneous catalyst is 1-20%; the noble metal and the transition metal are present in the form of metal salt compounds or complexes and are dissolved in the liquid phase.

Furthermore, the homogeneous catalyst is only added in a large amount when the device is started, and is added according to the mass concentration ratio of COD to metal ions of 5000:1-10:1, and is properly supplemented according to the catalyst loss rate and the concentration change of the reaction liquid during normal operation.

Further, the wet oxidation reactor is a bubbling flow internal circulation reactor of an inner cylinder, and under the condition of high temperature and high pressure, gaseous oxygen (air) is used as an oxidant to oxidize general organic matters in water into small molecular organic matters or inorganic matters; it should be understood by those skilled in the art that oil refining alkaline residue wastewater is typical wastewater difficult to treat, and the capability of removing complex organic matters such as naphthenic acid, phenols and the like in the alkaline residue wastewater is limited by single wet oxidation, but under the condition of a catalyst, free radical reaction is more likely to occur in oxygen at high temperature and high pressure, and the decomposition and conversion capability and reaction rate of the complex organic matters are greatly improved under the action of strong oxidizing property of the free radicals. On the other hand, the homogeneous catalyst has high activity and high selectivity, the special pollutant is treated more quickly and effectively, and the problem of easy loss is solved by a membrane technology.

Further, the reaction temperature of the wet oxidation reactor is 150-300 ℃, the reaction pressure is 2-10 MPa, and the liquid space velocity is 0.25-4 h ^-1 The volume ratio of the gas to the liquid is 20:1-500:1.

Furthermore, the cooling medium of the cooler is circulating water, the water discharged from the wet oxidation reactor is further cooled, the temperature is reduced to 30-50 ℃, and the requirement of the subsequent nanofiltration membrane on the temperature is met.

Furthermore, the nanofiltration water yield is 50% -80%, the membrane aperture is between 1-5 nm, and the nanofiltration water yield can intercept metals, high-valence salts (such as sulfate and carbonate), macromolecular organic matters (the relative molecular mass is more than 200) and the like of the homogeneous catalyst, and enter a concentrated water side after interception, wherein the metals of the homogeneous catalyst finally flow back to an adjusting tank, and return to a wet oxidation reactor for recycling after heat exchange and temperature rise; the nanofiltration water produced comprises unreacted micromolecular organic matters, monovalent salts and ammonia nitrogen.

The single-membrane electrodialysis only adopts an anion membrane, under the action of electrode driving and the anion membrane, some high-valence anion salts such as sulfate, carbonate and the like in nanofiltration concentrated water penetrate through the anion membrane to enter the concentrated water side, and meanwhile, the single-membrane electrodialysis also comprises small molecular organic matters showing negative, a cationic catalyst is remained in the mother solution, and the cation catalyst is returned to the regulating tank for recycling; it should be appreciated by those skilled in the art that nanofiltration does not trap monovalent ions such as sodium, potassium, chlorine, etc., but has a higher trapping rate for divalent anions, while single-membrane electrodialysis well solves the problem of divalent anion enrichment, and does not cause metal catalyst loss.

Further, the pH value of the neutralization tank is adjusted to 6-9 by adding sodium hydroxide or potassium hydroxide.

Further, the primary biochemical inlet water control salt concentration is below 250g/L, preferably 50-130 g/L. The salt tolerant bacteria GXNYJ-DL-1 used in the invention can still keep vitality and higher organic matter removal efficiency under the salt concentration of 250g/L, and combines the growth condition of the salt tolerant bacteria and the organic matter removal efficiency, and the salt concentration is preferably 50-130 g/L; the salt-tolerant bacteria GXNYJ-DL-1 also has higher sulfide toxicity tolerance.

Further, the primary biochemistry is selected from one of the processes of biological contact oxidation, MBBR and other high volume load, and the volume load is 1kg (COD ₅ ）/m ³ D is more than, the dissolved oxygen is controlled to be more than 2mg/L, and the residence time of the wastewater is 24-120 h.

Furthermore, the secondary biochemical technology is selected from BAF or MBR technology, the volume load is moderate, the COD can be removed, the filter function is also realized, the dissolved oxygen is controlled to be more than 2mg/L, and the residence time of the wastewater is 12-72 h.

Furthermore, the ozone catalytic oxidation unit utilizes hydroxyl free radicals generated by ozone under the catalytic action to further degrade naphthenic acid and phenolic substances remained in the wastewater, so that the biodegradability of the wastewater is improved; the ozone adding amount is 50-500mg (O) ₃ ) L (water).

It should be understood by those skilled in the art that the salt tolerant bacteria GXNYJ-DL-1 adopted in the two-stage biochemical stage solves the problem that common strains cannot survive under the condition of high salt content, and the sulfide toxicity tolerance of the salt tolerant bacteria also solves the problem that common salt tolerant bacteria have higher sulfide concentration and even cannot survive due to uneven aeration or local anaerobic oxidation of flora in the presence of a large amount of sulfate, and is particularly suitable for sulfate-based high-salt wastewater such as oil refining alkaline residue waste liquid; it should be further understood by those skilled in the art that ozone catalytic oxidation is a high-grade oxidation mode with high treatment cost, and the optimal treatment link is end advanced treatment.

Compared with the prior art, the invention has the following advantages:

(1) Aiming at the alkali residue wastewater difficult to treat by refining enterprises, the invention adopts the treatment process with homogeneous catalysis wet oxidation as a core, fully exerts the characteristics of high catalytic activity and high treatment efficiency of homogeneous catalysis wet oxidation, and greatly improves the treatment capacity of wet oxidation.

(2) The invention solves the problem of catalyst loss in homogeneous catalysis wet oxidation by combining wet oxidation with membrane technologies such as nanofiltration membrane, electrodialysis monoanion membrane and the like, realizes the recycling of the catalyst, and greatly reduces the use cost of the catalyst, especially noble metal catalyst.

(3) The salt-tolerant strain GXNYJ-DL-1 used by the invention has excellent salt tolerance, strong sulfide toxicity tolerance, strong vitality, high stability and large salt tolerance interval, plays an irreplaceable role in the treatment of the oil refining alkaline residue waste liquid, and lays a foundation for the use of the subsequent catalytic oxidation process and the control of the overall cost.

(4) The nanofiltration membrane and electrodialysis single-anion membrane double-membrane technology adopted by the invention also solves the problem of salt accumulation in the wastewater cyclic treatment process, and realizes salt balance in the wet oxidation cyclic treatment process. After the oil refining alkaline residue waste liquid is treated by the process, the direct discharge standard can be achieved under the condition of not limiting salt, and the requirement of entering a secondary sewage treatment field or a municipal sewage pipe network can be met under the extreme condition.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 growth curves of the strains of example 1 at different salt contents;

FIG. 2 shows the COD removal rate of the strain of example 1 at different salt contents;

FIG. 3 strain S in example 2 ^2- Growth curve at concentration;

FIG. 4 is a flow chart showing the treatment of the oil refining alkali residue waste liquid in example 3.

Description of biological Material preservation

The strain with high salt tolerance provided by the inventionHalomonasnigrificans) GXNYJ-DL-1 is preserved in China general microbiological culture Collection center (China Committee for culture Collection of microorganisms); address: the institute of microorganisms of national academy of sciences of China, national institute of sciences, no. 1, no. 3, north Chen West Lu, the Korean region of Beijing; preservation number: CGMCC No. 20350; preservation date: 7 months and 13 days 2020.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The embodiments and specific operation procedures are given on the premise of the technical scheme of the invention, but the protection scope of the invention is not limited to the following embodiments.

Example 1

Salt tolerance measurement of highly salt tolerant bacteria GXNYJ-DL-1:

the growth curves of the strains at different salt concentrations are shown in figure 1, and the COD removal rates of the strains at different salt concentrations after 72 hours are shown in figure 2. As can be seen from FIGS. 1 and 2, the strain grows better at a salt concentration of 10-130 g/L, the salt content increases with the adaptation period, but the COD removal rate (initial phenol COD of about 1247 mg/L) is maintained at a higher level; under the condition of the salt concentration of 250g/L, the strain adaptation period is as long as 50 hours, the strain starts to enter the growth period after the adaptation period, and OD ₆₀₀ The value is obviously increased, which indicates that the strain is not completely dead, and the corresponding COD removal rate is 53%.

According to the embodiment, the strain GXNYJ-DL-1 has strong salt tolerance, and the COD removal rate can still exceed 50% under the condition of the salt concentration of 250g/L, but the optimal salt concentration is 50-130 g/L.

Example 2

S-tolerance of high salt tolerant bacteria GXNYJ-DL-1 ^2- Toxicity determination:

strains at different S ^2- The growth curve under the concentration is shown in figure 3, the first 24 hours is a standing period, and the second 48 hours is a shaking reaction period of the shaking table. As can be seen from FIG. 3, the growth of the strain during standing is very slow, limited by the dissolved oxygen on the one hand and S on the other hand ^2- Toxicity inhibition, after 24h of standing period, starting shaking table shaking reaction, wherein the concentration of the strain starts to be obviously increased, but compared with example 1, the strain grows relatively slowly; after two days of growth, the wholeOD ₆₀₀ The value was increased from 0.25 to 0.45, indicating that the strain was not due to early S ^2- Is lost, and gradually resumes viability after a relatively long adaptation period, in particular at 300mg/L of S ^2- The strain concentration of the sample is steadily increasing.

As shown in the example, the strain GXNYJ-DL-1 has strong S resistance ^2- Toxicity capability, and is especially suitable for treating high sulfate-containing wastewater.

Example 3

The process method of the invention is adopted to treat the oil refining alkaline residue waste liquid

The process flow chart for treating the oil refining alkaline residue waste liquid is shown in fig. 4: the oil refining alkaline residue waste liquid firstly enters an adjusting tank, is mixed with single-membrane electrodialysis mother liquor and a homogeneous catalyst, is added with acid to adjust the pH, then enters a heat exchange unit, the heat exchange unit adopts a heat exchanger to exchange heat the effluent of a wet oxidation reactor and the effluent of the adjusting tank, the effluent of the wet oxidation reactor passes through a tube pass, the effluent of the adjusting tank passes through a shell pass, and enters the wet oxidation reactor after heat exchange and temperature rise; the effluent of the wet oxidation reactor enters a heat exchange unit for heat exchange and temperature reduction, then enters nanofiltration after being cooled by a cooler, after nanofiltration concentrated water is subjected to single-membrane electrodialysis treatment, mother liquor is returned to an adjusting tank, anion liquid flows to a neutralization tank, and nanofiltration product water also flows to the neutralization tank; the effluent from the neutralization pond enters a primary biochemical treatment, the primary biochemical treatment adopts salt-tolerant bacteria GXNYJ-DL-1 to treat the wastewater, the effluent enters a secondary biochemical treatment after being treated by an ozone catalytic oxidation section, the secondary biochemical treatment also adopts salt-tolerant bacteria GXNYJ-DL-1, and the effluent finally enters an effluent monitoring pond.

The water quality of a certain oil refining alkaline residue waste liquid is as follows: COD115600mg/L, phenol concentration 54000mg/L, chloride ion 1705mg/L, sulfate ion 14400mg/L, total salt content 59000mg/L, sulfide 7500mg/L, ammonia nitrogen 53mg/L, organic nitrogen 2305mg/L, total nitrogen 2530mg/L, pH 13.2, and inflow water flow 5t/h.

The oil refining alkaline residue waste liquid 5t/h enters an adjusting tank, is mixed with the single-membrane electrodialysis mother solution and the homogeneous catalyst in the adjusting tank, and is added with hydrochloric acid to adjust the pH value to 5.3, and the flow rate after mixing becomes 6.2t/h; the homogeneous catalyst adopts palladium-copper composite catalyst, which is palladium chloride and palladiumThe mixed salt of copper chloride, the concentration of palladium metal ions in the mixed liquid is about 15mg/L, the concentration of copper metal ions is about 250mg/L, the temperature of wastewater after heat exchange of effluent water of a regulating tank is raised to 150 ℃, and the wastewater enters a wet oxidation reactor; the reaction temperature of the wet oxidation reactor is 210 ℃, the pressure is 4MPa, and the liquid space velocity is 1h ^-1 The volume ratio of the gas to the liquid is 100:1; cooling wet oxidation effluent to 65 ℃ through a heat exchange unit, cooling to 45 ℃ through a cooler, and performing nanofiltration; the aperture of the nanofiltration membrane is 1.5nm, the water yield is 61.3%, metal catalysts, sulfate, macromolecular organic matters and the like are intercepted and enter a concentrated water side, and most sodium, potassium, chloride ions, ammonia nitrogen, micromolecular organic matters and the like penetrate the nanofiltration membrane and enter the water producing side; the first-stage nanofiltration concentrated water enters a single-mode electrodialysis treatment, a single-mode electrodialysis anion liquid flows to a neutralization tank, and a mother solution flows to an adjusting tank; the pH value of the neutralization tank is increased to 6.5 by adding sodium hydroxide, and then the primary biochemical treatment is carried out; the primary biochemical treatment adopts a biological contact oxidation pond process, the strain is salt-tolerant bacteria GXNYJ-DL-1, the dissolved oxygen is controlled to be more than 2mg/L, the retention time of wastewater is 72 hours, the effluent enters the secondary biochemical treatment after ozone catalytic oxidation treatment, and the ozone adding amount is 200mg (O) ₃ ) L (water); the second-stage biochemistry adopts a BAF process, salt-tolerant bacteria GXNYJ-DL-1 is adopted, the retention time of the wastewater is 24 hours, the effluent is discharged to a effluent monitoring pool, the COD of the final wastewater is 46mg/L, sulfide is less than 1mg/L, ammonia nitrogen is 2mg/L, total nitrogen is 13mg/L, and the wastewater meets the requirements of emission standards of pollutants in petroleum refining industry (GB 31570-2015) and can be discharged up to the standard. The effect of removing the pollution factors of each unit is shown in table 1, and the wet oxidation treatment efficiency is shown in table 2.

TABLE 1

TABLE 2

According to the embodiment, the process method realizes the efficient operation of homogeneous catalytic wet oxidation, and aims at the problems of high COD, high nitrogen, high toxicity, difficult degradation and the like of the oil refining alkaline residue waste liquid, the COD removal rate of the wet oxidation unit in the embodiment is as high as 95.6%, the total nitrogen removal rate is as high as 98.1%, the sulfide removal rate is greater than 99%, and finally the standard emission (without limiting salt) of the oil refining alkaline residue waste liquid is realized. Meanwhile, the problem of loss of the homogeneous catalyst is solved by combining the membrane technology, and the recycling of the catalyst is realized.

Example 4

Treatment of certain refinery caustic sludge effluent using the process shown in fig. 4:

the oil refining alkaline residue waste liquid has the following water quality: COD 203400mg/L, phenol concentration 75000mg/L, chloride ion 3556mg/L, sulfate ion 21000mg/L, total salt content 101000mg/L, sulfide 10490mg/L, ammonia nitrogen 110mg/L, organic nitrogen 2503mg/L, total nitrogen 3150mg/L, pH 13.5, and wastewater flow 5t/h.

The oil refining alkaline residue waste liquid 5t/h enters an adjusting tank, is mixed with the single-membrane electrodialysis mother solution and the homogeneous catalyst in the adjusting tank, and is added with hydrochloric acid to adjust the pH value to 5, and the flow rate becomes 6t/h after mixing; the homogeneous catalyst adopts a palladium-copper composite catalyst which is a mixed salt of palladium chloride and copper chloride, the concentration of palladium metal ions in the mixed liquid is about 20mg/L, the concentration of copper metal ions is about 350mg/L, the temperature of wastewater after heat exchange of effluent water of a regulating tank is raised to 150 ℃, and the wastewater enters a wet oxidation reactor; the reaction temperature of the wet oxidation reactor is 220 ℃, the pressure is 4.5MPa, and the liquid space velocity is 1h ^-1 The volume ratio of the gas to the liquid is 100:1; cooling wet oxidation effluent to 65 ℃ through a heat exchange unit, cooling to 45 ℃ through a cooler, and performing nanofiltration; the aperture of the nanofiltration membrane is 1.5nm, the water yield is 60%, metal catalysts, sulfate, macromolecular organic matters and the like are trapped and enter a concentrated water side, and most sodium, potassium, chloride ions, ammonia nitrogen, micromolecular organic matters and the like penetrate the nanofiltration membrane and enter the water producing side; the first-stage nanofiltration concentrated water enters a single-mode electrodialysis treatment, a single-mode electrodialysis anion liquid flows to a neutralization tank, and a mother solution flows to an adjusting tank; the pH value of the neutralization tank is increased to 6.4 by adding sodium hydroxide, and then the primary biochemical treatment is carried out; the primary biochemical treatment adopts a biological contact oxidation pond process, the strain is salt-tolerant bacteria GXNYJ-DL-1, the dissolved oxygen is controlled to be more than 2mg/L, the retention time of wastewater is 96 hours, and the effluent is treated by ozone catalytic oxidationEntering secondary biochemistry, the ozone adding amount is 200mg (O) ₃ ) L (water); the second-stage biochemistry adopts a BAF process, salt-tolerant bacteria GXNYJ-DL-1 is adopted, the retention time of wastewater is 48 hours, effluent is discharged to a effluent monitoring pool, the COD of the final wastewater is 335mg/L, sulfide is less than 1mg/L, ammonia nitrogen is 1mg/L, and total nitrogen is 15mg/L, thereby meeting the requirement of entering a second-stage sewage treatment field or municipal sewage pipe network. The effect of removing the pollution factors of each unit is shown in Table 3, and the wet oxidation treatment efficiency is shown in Table 4.

TABLE 3 Table 3

TABLE 4 Table 4

According to the embodiment, the process method can treat the oil refining alkaline residue waste liquid with different concentrations, and finally realizes the efficient treatment of the oil refining alkaline residue waste liquid by adjusting various modes such as the addition amount of the catalyst, the nanofiltration water yield, the two-stage biochemical residence time and the like, so that the related emission standard is met.

Example 5

the oil refining alkaline residue waste liquid has the following water quality: COD 261500mg/L, phenol concentration 82000mg/L, chloride ion 5650mg/L, sulfate ion 41000mg/L, total salt content 155470mg/L, sulfide 23490mg/L, ammonia nitrogen 150mg/L, organic nitrogen 4512mg/L, total nitrogen 5330mg/L, pH 13.5, and wastewater flow 5t/h.

The total salt content of the oil refining alkaline residue waste liquid is 155470mg/L, which exceeds the optimal salt tolerance interval (10-130 g/L) of the salt tolerant bacteria GXNYJ-DL-1, and in order to obtain better treatment effect, the oil refining alkaline residue waste liquid is diluted by fresh water in small quantity, the volume ratio of the oil refining alkaline residue waste liquid to the fresh water is 1:1, and the total salt content of the mixed water is below 80000mg/L after dilution. The specific operation conditions of the alkali residue wastewater treatment are similar to those of the embodiment 3, and finally the water is discharged into and discharged from the water regulating tank.

According to the embodiment, the invention can effectively treat the ultrahigh-concentration oil refining alkaline residue waste liquid only by a small amount of dilution water, and the effluent meets the relevant emission standard.

Example 6

The water quality for treating the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are the same as those of example 3, the catalyst is changed to palladium-iron catalyst, the pH of the tank is adjusted to 3.5, the pH of the neutralization tank in the advanced treatment section is adjusted back to 6.5, and the wet oxidation section treatment results are shown in Table 5.

TABLE 5

According to the embodiment, the palladium-iron composite catalyst is used, the addition amount is unchanged, the COD removal rate of the homogeneous catalysis wet oxidation is slightly increased, and the total nitrogen removal rate is slightly reduced.

Example 7

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are also the same as those of example 3, only the types of catalysts are different, and the wet oxidation treatment results are shown in Table 6.

TABLE 6

As is clear from the present example, the addition amount of the palladium-zinc composite catalyst was unchanged, and the COD removal rate and the total nitrogen removal rate by the homogeneous catalytic wet oxidation were both reduced as compared with example 3.

Example 8

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are also the same as those of example 3, only the types of catalysts are different, and the treatment results of the wet oxidation unit are shown in Table 7.

TABLE 7

As is clear from the present example, the addition amount of rhodium-copper composite catalyst was not changed, and the COD removal rate and the total nitrogen removal rate by the homogeneous catalytic wet oxidation were further improved as compared with example 3.

Example 9

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are also the same as those of example 3, only the types of catalysts are different, and the treatment results of the wet oxidation unit are shown in table 8.

TABLE 8

As is clear from the present example, the addition amount of the platinum-copper composite catalyst was unchanged, and the COD removal rate by the homogeneous catalytic wet oxidation was slightly increased, but the total nitrogen removal rate was reduced to 88.4% as compared with example 3.

Example 10

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are also the same as those of example 3, only the types of catalysts are different, and the treatment results of the wet oxidation unit are shown in table 9.

TABLE 9

As is clear from the present example, the removal rate of COD and the removal rate of total nitrogen by homogeneous catalytic wet oxidation were both significantly reduced compared with example 3 by changing to the platinum-nickel composite catalyst.

Example 11

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are also the same as those of example 3, only the types and the addition amount of the catalyst are different, and the treatment results of the wet oxidation unit are shown in table 10.

Table 10

As is clear from the present example, the addition amount of the platinum-nickel composite catalyst was increased as compared with example 10, and the COD removal rate by the homogeneous catalytic wet oxidation was significantly increased as compared with example 10, which is equivalent to example 1, but the total nitrogen removal rate was not significantly changed.

Comparative example 1

The water quality of the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are the same as those of example 3, but no noble metal catalyst is added, only the transition metal catalyst is added, and the wet oxidation unit treatment results are shown in table 11.

TABLE 11

According to the comparative example, no noble metal catalyst is added, only copper metal catalyst is added, the COD removal rate and the total nitrogen removal rate of the homogeneous catalytic wet oxidation are obviously reduced, the COD removal rate is only 73.1%, the total nitrogen removal rate is only 72.5%, and the sulfide removal rate is 98.2%.

Comparative example 2

The water quality for treating the oil refining alkaline residue waste liquid is the same as that of example 3, the process route, implementation steps and reaction parameters are the same as those of example 3, neither noble metal catalyst nor transition metal catalyst is added, the reaction temperature of the wet oxidation reactor is 210 ℃, the pressure is 4MPa, and the liquid airspeed is 1h ^-1 The gas-liquid volume ratio was 100:1, and the wet oxidation unit treatment results are shown in Table 12.

Table 12

As is clear from the comparative example, the conventional wet oxidation was performed without adding a catalyst, the reaction conditions were the same as in example 3, the final COD removal rate was only 35.2%, the total nitrogen removal rate was only 15.8%, and the sulfide removal rate was in the normal range. Therefore, the conventional wet oxidation process has limited capability of removing organic matters and total nitrogen, and the removal of COD is more of the pseudo COD removal caused by sulfides.

Comparative example 3

The water quality for treating the oil refining alkaline residue waste liquid is the same as that of the example 3, the process route, the implementation steps and the reaction parameters are also the same as those of the example 3, the common COD removing strain is only added into the two-stage biochemical units, and the pollution factor concentration result is shown in the table 13.

TABLE 13

As shown in Table 13, the removal rate of COD is only 16.9% when the total salt content is up to 68334mg/L, which is far smaller than that of example 3, but the secondary biochemical COD is not removed but is raised, which is the phenomenon of raising the concentration of COD caused by autolysis of cells due to poisoning and death of activated sludge, and the primary biochemical pond has no COD raising phenomenon because of long residence time (72 h), a small amount of sludge starts to exert the COD removing function after the adaptation period, and the residence time of the secondary biochemical pond is only 24h.

As can be seen from the comparative example, the salt tolerant bacteria GXNYJ-DL-1 adopted by the two-stage biochemical unit has advantages over the common bacteria in the advanced treatment section of the oil refining alkaline residue waste liquid, and has the advantages of wide salt tolerance range, strong impact resistance and high treatment efficiency.

Claims

1. The homogeneous catalysis wet oxidation treatment process of oil refining alkali slag waste liquid includes wet oxidation section and advanced treatment section;

2. The method according to claim 1, wherein an acid is added to the adjustment tank to adjust the pH to 2 to 6, the acid being hydrochloric acid or sulfuric acid.

3. The method according to claim 1, wherein the heat exchange unit increases the temperature of the effluent of the conditioning tank to 130-160 ℃, and decreases the temperature of the effluent of the wet oxidation reactor to 50-75 ℃.

4. The method according to claim 1, wherein the homogeneous catalyst is a noble metal and transition metal complex catalyst; the noble metal is one or more of platinum, palladium, rhodium, silver and ruthenium, the transition metal is one or more of copper, iron, manganese, zinc and nickel, preferably a palladium copper or rhodium copper composite catalyst, and the mass percentage of the noble metal in the homogeneous catalyst is 1-20%; the noble metal and the transition metal are present in the form of metal salt compounds or complexes and are dissolved in the liquid phase.

5. The method according to claim 4, wherein the homogeneous catalyst is added according to a mass concentration ratio of COD to metal ions of 5000:1-10:1, and the catalyst is supplemented according to a catalyst loss rate and a reaction solution concentration change during operation.

6. The method according to claim 1, wherein the wet oxidation reactor is a bubbling flow internal circulation reactor of an inner cylinder, and oxygen is used as an oxidant to oxidize general organic matters in water into small molecular organic matters or inorganic matters.

7. The method according to claim 6, wherein the wet oxidation reactor has a reaction temperature of 150-300 ℃, a reaction pressure of 2-10 MPa and a liquid space velocity of 0.25-4 h ^-1 The volume ratio of the gas to the liquid is 20:1-500:1.

8. The method according to claim 1, wherein the cooler reduces the wet oxidation reactor effluent temperature to 30-50 ℃.

9. The method of claim 1, wherein the nanofiltration water yield is 50% -80% and the membrane pore size is between 1 and 5 nm.

10. The method of claim 1, wherein the single-membrane electrodialysis adopts an anion membrane, high-valence anion salt and negative micromolecular organic matters in nanofiltration concentrated water enter a concentrated water side through the anion membrane under the action of electrode driving and the anion membrane, and a cationic catalyst is remained in a mother solution and flows back to the regulating tank for recycling.

11. The method according to claim 1, wherein the pH is adjusted to 6-9 in the neutralization tank by adding sodium hydroxide or potassium hydroxide.

12. The method according to claim 1, wherein the primary biochemical feed water control salt concentration is 250g/L or less, preferably 50-130 g/L.

13. The method according to claim 1, wherein the primary biochemical is selected from one of biological contact oxidation and MBBR process, and the volumetric load is 1kg (COD ₅ ）/m ³ D is more than, the dissolved oxygen is controlled to be more than 2mg/L, and the residence time of the wastewater is 24-120 h.

14. The method of claim 1, wherein the secondary biochemical process is selected from BAF or MBR process, the dissolved oxygen is controlled above 2mg/L, and the wastewater residence time is 12-72 h.

15. The method according to claim 1, wherein the ozone is added in an amount of 50-500mg O in the ozone catalytic oxidation ₃ water/L.