CN107010709B - A kind of purification method of high-concentration phenol-containing wastewater in ortho/hydroquinone production process - Google Patents

Abstract

The invention discloses a method for purifying high-concentration phenol-containing waste water in the production process of ortho/hydroquinone. Air, with air as oxidant, enters the fluidization section of the cyclone fluidized bed reactor from the bottom of the reactor, and another air enters the reactor tangentially from the enlarged section; the phenol-containing wastewater is added from the top to the reactor. In the fluidized section of the cyclone fluidized bed reactor, under the action of the catalytic cracking oxidation catalyst, the phenols in the wastewater and the air undergo catalytic cracking and oxidation reaction, and the generated gas enters the fixed bed reactor from the top, and the deep oxidation catalyst Under the action of the deep oxidation reaction, the gas is discharged from the outlet of the fixed bed reactor, and passes through the heat exchanger and the gas-liquid separator in turn. The obtained condensate is sent to the rain drainage system, and the non-condensable gas is directly vented and discharged. The invention can treat phenol-containing wastewater with high efficiency, low cost and low energy consumption.

Description

A kind of purification method of high-concentration phenol-containing wastewater in ortho/hydroquinone production process

technical field

The invention belongs to the field of treatment of high-concentration phenol-containing wastewater, in particular to a method for purifying high-concentration phenol-containing wastewater in the production process of ortho/hydroquinone.

Background technique

Ortho-hydroquinone is an important raw material, auxiliary agent and intermediate for rubber, medicine, pollution, pesticide and fine chemical industry. The production process of ortho-hydroquinone is mainly based on hydrogen peroxide oxidation and phenol hydroxylation. The reaction equation is as follows: Show:

The process uses water as the reaction medium, adopts about 30wt% hydrogen peroxide as the oxidant, and under the action of the catalyst, oxidizes phenol to ortho/hydroquinone and generates water at the same time. After the oxidized reaction solution is extracted by methyl isobutyl ketone, most of the water can be recycled, but there is still a part of the water that must be purified. This part of the water contains phenol, ortho/hydroquinone, phenol tar and methyl alcohol. Hazardous chemicals such as isobutyl ketone.

Phenol and its derivatives are highly toxic and refractory organic compounds. Due to their serious harm to the environment and human health, phenol-containing wastewater must be effectively dephenolized before being discharged. The standard for direct discharge of volatile phenolic wastewater (GB31571-2015) in my country is 0.5 mg/L. In areas prone to serious water pollution problems and requiring special protection measures, the direct discharge standard for volatile phenolic wastewater is 0.3 mg/L. In recent years, scholars at home and abroad have done a lot of research work on the treatment of phenol-containing wastewater, and developed a variety of treatment methods, including physical methods, catalytic oxidation methods, chemical oxidation methods, biochemical methods, electrochemical methods, photodegradation methods, etc. .

The physical treatment of phenol-containing wastewater mainly includes extraction and adsorption. The selection of the most critical extractant in the extraction and dephenolization technology, U.S. Patent 6,071,409 uses alkyl tertiary amyl ether as the extractant, and the dephenolization rate of one extraction can reach more than 90% (the phenol content in the raw water is 7000mg/L). The phenolic content in the residual liquid is still about 700mg/L; Chinese Patent No. 105540969 discloses the use of eucalyptol as an extractant to treat phenolic wastewater with a phenolic content of 5000mg/L, and the removal rate of phenol in a single extraction can reach 96.2%. Extraction technology for treating phenol-containing wastewater generally has the disadvantages of high cost of extractant and high energy consumption for regeneration, and the phenol content and organic chemical oxygen demand (COD) in the wastewater after extraction are difficult to meet the discharge standards of industrial wastewater. Therefore, this process is often used as a The pretreatment method of high-concentration phenol-containing wastewater is used to recover phenols in wastewater. The raffinate is treated by other means, and the commonly used treatment method is biochemical method. The adsorption dephenolization technology is prone to secondary pollution because most of the adsorbents are expensive and the adsorption regeneration cost is high.

Wet oxidation is an effective oxidation technology developed by American scientist Zimmermann in the 1950s to treat toxic, harmful and high-concentration organic wastewater. It has now been used in the treatment of phenol-containing wastewater. Inchaurrondo et al. developed a wet catalytic oxidation catalyst CuO-γAl ₂ O ₃ and applied it to phenol wastewater treatment. Under optimal conditions, the phenol removal rate can reach 100%, and the total organic carbon (TOC) can reach 80% (CHEMICAL ENGINEERING JOURNAL , 2012.198:426-434.). Chinese patent ^{201510245064.2} discloses the preparation of a wet catalytic oxidation catalyst and a method for purifying phenolic wastewater based on the catalyst. At 160℃, the removal rate of phenol can reach 96.4%, and the removal rate of COD is 75%. Wet catalytic oxidation completely degrades COD. The temperature needs to reach about 250 °C and the operating pressure is 4 to 8 MPa. The material of the reactor is required to be resistant to high temperature, high pressure and corrosion. At the same time, the wet oxidation method is difficult to achieve the treatment of phenol-containing wastewater in one step. Emission standards still require secondary harmless treatment, thus restricting the industrial application of wet catalytic oxidation.

Biodegradation is currently the most important method for treating phenol-containing wastewater. Gonzalez et al. gelled Pseudomonas with calcium alginate into spider bodies, and successfully used it in a fluidized bed bioreactor to treat phenol-containing wastewater produced by a phenolic resin factory. Before entering the fluidized bed, the phenol concentration was diluted to 1000mg/L, the pH is controlled at 6.6 during operation, the temperature is 30°C, the intake air volume is 85L/h, and the dissolved oxygen is 2-4.5mg/L, the phenol removal rate is more than 90%, and the phenol residue in the treated water still contains 100mg/L. About L (BIORESOURCE TECHNOLOGY, 2001.80(2):137-142.). The disadvantage of the biodegradation method is that phenolic substances have toxic effects on bacterial species and cannot treat high-concentration phenol-containing wastewater. Therefore, when the phenol-containing wastewater is treated by the biodegradation method, the phenol-containing wastewater needs to be pretreated to reduce the phenol content in the wastewater, so that the microorganisms can survive. Under normal circumstances, when phenol-containing wastewater enters the biochemical tank, it is necessary to control the phenol concentration in the wastewater to not exceed 1000 mg/L. At the same time, the biological treatment method has the disadvantages of large device footprint and high operation and management requirements.

In recent years, photocatalysis has been extensively studied as an advanced oxidation technology. Patent CN201310338889.X discloses a device and method for photocatalytic degradation of phenol-containing wastewater. The core of the device is a turntable reactor, including a shell, a turntable, a rotating shaft, an excitation light source, a liquid inlet pipe and a liquid outlet pipe. The turntable and the inner wall of the casing are loaded with catalysts, and excitation light sources are installed on the upper and lower sides of the turntable to increase the photocatalytic reaction time and enhance the mass transfer effect. Taking wastewater with a phenol content of 500 mg/L as the simulation object, when the rotating speed of the turntable is 500 r/min, the light source is a 254 nm low-pressure mercury lamp, the light intensity is 18.35 mW/cm ² , and the space velocity is 50 L/h, and the phenol content is measured by sampling and analysis after 4 hours. The removal rate was 98.34%, and the residual phenol concentration was about 8 mg/L. This method has the defects of difficult separation of catalyst, complex reactor structure and low utilization rate of light energy. Chinese patent CN20131029323.3 discloses a treatment method for photodegrading phenol wastewater under the irradiation of ultraviolet lamps, using chlorine dioxide as an oxidant, activated carbon-loaded nano-scale titanium dioxide as a catalyst. The contents of COD and phenol in the wastewater before treatment were 433.7 mg/L and 195 mg/L, respectively, and the contents of COD and phenol in the wastewater after treatment were 78.5 mg/L and 1.09 mg/L, respectively. The removal rates of COD and phenol reached 81.6% and 99.5%. The phenol-containing wastewater after photocatalytic treatment still needs secondary treatment, and because the photodegradation method requires light, the transparency of the wastewater is related to the degradation effect, and this method cannot treat the wastewater with turbidity or poor water quality transparency.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a method for purifying and treating phenol-containing wastewater produced by an extraction process in a phenol hydroxylation production process.

The purpose of this invention is to realize through the following technical solutions:

A method for purifying high-concentration phenol-containing wastewater in the production process of ortho/hydroquinone, comprising the following steps:

(1), configure an air inlet at the upper expansion section and the bottom of the cyclone fluidized bed reactor, and feed two air streams simultaneously, take the air as an oxidant, and a stream of air enters the cyclone fluidized bed reactor from the bottom of the reactor. In the fluidization section, another air enters the reactor from the tangential direction of the expansion section, so that the catalyst particles and organic molecules in the expansion section are returned to the fluidization section under the action of the air cyclone; the phenol is hydroxylated to produce ortho/ The phenol-containing wastewater produced in the hydroquinone process is added from the top of the cyclone fluidized bed reactor to the fluidized section of the cyclone fluidized bed reactor. Under the action of the catalytic cracking oxidation catalyst, the organic matter and air in the wastewater are catalyzed. cracking oxidation reaction;

(2) The gas generated after catalytic cracking and oxidation enters the fixed bed reactor connected in series with the cyclone fluidized bed reactor from the top, and carries out a deep oxidation reaction under the action of a deep oxidation catalyst to further reduce the small molecules after the cracking of organic matter in the gas. organic matter;

(3) The deeply oxidized gas is discharged from the outlet of the fixed bed reactor, and then passes through the heat exchanger and the gas-liquid separator in turn, and the obtained condensate is sent to the rain drainage system, and the non-condensable gas is directly vented and discharged.

The phenol-containing waste water of the present invention is the phenol-containing waste water produced by the extraction process during the production of ortho/hydroquinone by hydroxylation of phenol. The main organic substances in the phenol-containing wastewater are phenol, hydroquinone, catechol, resorcinol, phenol tar and extraction agent methyl isobutyl ketone.

The chemical oxygen demand (COD) of the phenol-containing wastewater is 1,000-100,000 mgO ₂ /L; the total phenol concentration in the phenol-containing wastewater is 100-10,000 mg/L, and the total phenol concentration refers to phenol, p-benzene in the wastewater The total concentration of diphenol, catechol and resorcinol, measured in mg/L.

In step (1), the feed space velocity of phenol-containing wastewater is 0.05～0.6L/(kg _{cat, cyclone fluidized bed} h), and the total feed space velocity of air is 400～1500L/(kg _{cat, cyclone flow} Fluidized _bed h), the volume ratio of the air entering the fluidized section from the bottom of the cyclone fluidized bed reactor to the air entering the expanding section tangentially is 9/1 to 2/1. In the present invention, the feed space velocity and air feed space velocity of the phenol-containing wastewater refer to the space velocity relative to the catalyst in the swirling fluidized bed.

The reaction pressure of the catalytic cracking oxidation reaction is 0.1-0.25MPa (absolute pressure, the same below), and the reaction temperature is 300-450°C.

The catalytic cracking oxidation catalyst is a metal oxide catalyst, and is active with 1 metal oxide or a composite of no more than 3 metal oxides in metal oxides such as ruthenium, palladium, platinum, gold, rubidium, chromium, and manganese. Component, one of Y molecular sieve, ZSM-5, MCM-22, MCM-41, SBA-15 and β molecular sieve is used as a carrier, and the loading amount of the active component is 1-20%. The particle size of the catalytic cracking oxidation catalyst is 40-200 μm. The catalytic cracking oxidation catalyst is prepared by a spray drying method. The preparation method is as follows: the precursor of the active component is dissolved in water, the carrier powder is immersed in the above aqueous solution for 12 hours, and a binder with a mass of 10-12% of the carrier is added and stirred evenly. Spray molding in a spray dryer, drying at 120°C, and calcining at 550°C for 3 hours to obtain a metal oxide catalyst. Among them, when the active components are PtO ₂ , PdO, RuO ₂ and Au ₂ O ₃ , the corresponding precursors are chloride salts; when the active components are MnO ₂ , Rb ₂ O, Cr ₂ O ₃ , the corresponding precursors are The precursor is nitrate.

In step (2), the filling amount of the deep oxidation catalyst in the fixed bed reactor is the same as the quality of the catalytic cracking oxidation catalyst in the cyclone fluidized bed reactor; the reaction pressure of the deep oxidation in the fixed bed reactor is the same as that of the cyclone fluidized bed reactor. The pressure remains the same, and the reaction temperature is 300-400 °C. The gas at the outlet of the fixed bed reactor contains water vapor, carbon dioxide and unreacted organic vapor. This part of the gas is cooled to 40-60°C in the heat exchanger, and the COD in the condensate obtained through the gas-liquid separator is less than or equal to 80mgO ₂ /L, the total phenol concentration is less than 0.5mg/L, which has reached the rainwater drainage standard (surface water environmental quality standard GB3838-2002), and the VOCs content in the non-condensable gas leaving the top of the gas-liquid separator does not exceed 20mg/L m ³ , reaching the comprehensive emission standard of air pollutants (GB16297-1996) and the emission standard of volatile organic compounds in the chemical industry of Jiangsu Province.

The deep oxidation catalyst is a metal oxide catalyst, and one metal oxide or a composite of no more than three metal oxides in metal oxides such as lanthanum, iron, cobalt, nickel, cerium, copper, and iridium is used as the active group. One of alumina, silica, activated clay and attapulgite is used as a carrier, and the loading amount of the active component is 10-20%. The particle size of the deep oxidation catalyst is 2-5mm, which is prepared by dipping method and formed by extrusion: the precursor of the active component is dissolved in water, mixed with the carrier evenly, and then extruded in an extruder. Drying at 120°C and calcining at 550°C for 3 hours obtains metal oxide catalysts; when the active components are La ₂ O ₃ , CuO, NiO, Co ₂ O ₃ , Fe ₂ O ₃ , CeO ₂ , the corresponding precursors It is nitrate; when the active component is IrO ₂ , its corresponding precursor is chloride salt.

Another object of the present invention is to provide a purification system for high-concentration phenol-containing wastewater in the production process of ortho/hydroquinone. The purification system includes a series of cyclone fluidized bed reactors, fixed bed reactors, The cyclone fluidized bed reactor includes a lower fluidized section and an upper enlarged section, the catalytic cracking oxidation catalyst is loaded in the fluidized section, and a tangential inlet is provided in the enlarged section of the cyclone fluidized bed reactor. The air inlet realizes tangential entry of air, an axial air inlet is arranged at the bottom of the cyclone fluidized bed reactor, and a waste water inlet and a gas outlet are arranged at the top of the cyclone fluidized bed reactor; the gas outlet of the cyclone fluidized bed reactor is connected to the The gas inlet at the top of the fixed-bed reactor is connected, the fixed-bed reactor is filled with a deep oxidation catalyst, and the outlet at the bottom of the fixed-bed reactor is connected with the heat exchanger.

The cyclone fluidized bed reactor in the present invention is a conventional reactor.

The beneficial effects of the present invention are as follows:

The invention aims at the treatment method of phenol-containing wastewater produced in the process of producing ortho/hydroquinone by phenol hydroxylation, has the characteristics of simple process, mild conditions and easy realization, and can realize the treatment of refractory degradation with high efficiency, low cost and low energy consumption. , high toxicity and high concentration of phenol-containing wastewater, after the phenol-containing wastewater passes through the purification system of the cyclone fluidized bed reactor and the fixed bed reactor in series, the chemical oxygen demand and phenol content in the effluent meet the corresponding discharge standards, no need It can be discharged after secondary treatment, and the VOCs content in the obtained gas reaches the emission standard, and can be directly discharged without further treatment. By adopting the method of the invention, equipment investment can be greatly reduced, and the purpose of protecting the environment is also achieved.

Description of drawings

Fig. 1 is the flow chart of the purification method of high-concentration phenol-containing wastewater in the ortho/hydroquinone production process of the present invention;

In Figure 1, 1-cyclone fluidized bed reactor, 2-fixed bed reactor, 3-heat exchanger, 4-gas-liquid separator.

Detailed ways

As shown in Figure 1, a purification system for high-concentration phenol-containing wastewater in the production process of ortho/hydroquinone, the purification system comprises a cyclone fluidized bed reactor 1, a fixed bed reactor 2, a heat exchange 3 and gas-liquid separator 4; the cyclone fluidized bed reactor 1 includes a lower fluidized section and an upper expansion section, the catalytic cracking oxidation catalyst is loaded in the fluidized section, and the expanded section of the cyclone fluidized bed reactor 1 is installed. There is a tangential air inlet to realize tangential entry of air, an axial air inlet is arranged at the bottom of the cyclone fluidized bed reactor, and a waste water inlet and a gas outlet are arranged at the top of the cyclone fluidized bed reactor 1; The gas outlet of the reactor 1 is connected with the gas inlet at the top of the fixed bed reactor 2, and the fixed bed reactor 2 is filled with a deep oxidation catalyst of the same quality as the catalytic cracking oxidation catalyst in the cyclone fluidized bed reactor, and the fixed bed reaction The outlet at the bottom of the heat exchanger 2 is connected to the heat exchanger 3.

The process flow of phenol-containing wastewater purification treatment is as follows: two streams of air are introduced into the cyclone fluidized bed reactor, and air 1 enters the fluidized section from the bottom of the cyclone fluidized bed, so that the catalytic cracking oxidation catalyst is in a fluidized state, and air 2 is in a fluidized state. From the enlarged section of the cyclone fluidized bed reactor, it enters the enlarged section tangentially, so that the catalyst particles and organic molecules in the enlarged section are driven by the tangential airflow to generate a cyclone and enter the fluidized section to fully contact the catalyst; The phenol-containing wastewater is passed into the fluidized section at the top of the bed, and the catalytic cracking and oxidation reaction occurs; the gas at the outlet of the cyclone fluidized bed reactor contains a trace amount of unpurified organic vapor, which enters into the fixed steam in series with the cyclone fluidized bed reactor. The bed reactor conducts a deep oxidation reaction, and after the series catalytic purification of the cyclone fluidized bed reactor and the fixed bed reactor, the gas at the outlet of the fixed bed reactor is cooled by the heat exchanger and the COD in the condensate obtained is less than or equal to 80mgO ₂ /L, the total phenol concentration is less than 0.5mg/L, it can directly enter the rain drainage system, and the content of VOCs in the vented non-condensable gas does not exceed 40mg/m ³ , which can be directly emptied.

The phenolic content in water was analyzed by liquid spectrometry, and the analysis conditions were as follows: the mobile phase was a mixture of methanol and water, the volume ratio was 2:3, the liquid chromatography column was a C18 column, and the wavelength was 277 nm.

COD detection was carried out with 6B-200 COD speed tester. The content of VOCs in the gas phase was analyzed by chromatography. The chromatographic column was a capillary column, and the standard gas was methane. The gas chromatography conditions were as follows: the column temperature was 100 °C, and the temperature of the detector and the vaporization chamber were both 200 °C.

The present invention will be further described in detail below in conjunction with the examples.

Example 1

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 10000mgO ₂ /L, and the total phenol concentration is 100mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is PtO ₂ /MCM-41, the loading amount of PtO ₂ is 1.5%, and the loading amount is 40 g. The catalyst is prepared by spray drying method. Preparation method: 27.1 g H ₂ PtCl ₆ Dissolve in 300ml of water, immerse 900g MCM-41 molecular sieve in the above aqueous solution for 12h, add 333g of silica sol (SiO ₂ content 30%), stir well, spray in a spray dryer, dry at 120°C, 550 After calcination at ℃ for 3h, the particle size of the catalyst is 60-200 μm. The deep oxidation catalyst packed in the fixed bed reactor is CuO-Fe ₂ O ₃ /Al ₂ O ₃ , the loading amount of CuO is 15%, the loading amount of Fe ₂ O ₃ is 5%, and the catalyst is prepared by a mixing rolling method. The preparation method : Dissolve 351.7g Cu(NO ₃ ) ₂ and 253g Fe(NO ₃ ) ₃ ·9H ₂ O in 350ml of water, mix them with 1000g Al ₂ O ₃ evenly, then extrude them in an extruder and dry at 120°C , calcined at 550°C for 3h, and the catalyst particle size was 2-4mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.11MPa (absolute pressure, the same below), the catalytic cracking oxidation reaction temperature was 300°C, and the deep oxidation reaction temperature was 361°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 320L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 80L/(kg _{cat, cyclone fluidized bed} h), the feed space velocity of phenol-containing wastewater is 0.1L/(kg _{cat, cyclone fluidized bed} h); the deeply oxidized gas is discharged from the outlet of the fixed bed reactor, After passing through the heat exchanger and the gas-liquid separator in sequence, the COD in the obtained condensate was 71.4 mgO ₂ /L, the total phenol concentration was 0.47 mg/L, and the VOCs in the non-condensable gas was 17.1 mg/m ³ .

Example 2

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 18000mgO ₂ /L, and the total phenol concentration is 1650mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is RuO ₂ -MnO ₂ /SBA-15, the loading amount of RuO ₂ is 1%, the loading amount of MnO ₂ is 15%, and the loading amount is 40 g, and the catalyst is spray-dried Preparation method: Dissolve 15.6g RuCl ₃ ·3H ₂ O, 401ml 50% Mn(NO ₃ ) ₂ solution in 200ml water, immerse 900g/SBA-15 molecular sieve in the above aqueous solution for 12h, add 333g silicon The sol (SiO ₂ content of 30%) was stirred evenly, sprayed in a spray dryer, dried at 120° C., calcined at 550° C. for 3 hours, and the catalyst particle size was 60-200 μm. The deep oxidation catalyst loaded in the fixed bed reactor is La ₂ O ₃ /attapulgite, and the loading amount _of La ₂ O ₃ is _{20 %} . O is dissolved in 300ml of water, mixed with 1000g of attapulgite evenly, and then extruded into an extruder, dried at 120°C, calcined at 550°C for 3 hours, and the catalyst particle size is 2-4mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.15MPa, the catalytic cracking oxidation reaction temperature was 350°C, and the deep oxidation reaction temperature was 367°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 400L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 150L/(kg _{cat, cyclone fluidized bed} ·h), and the feed space velocity of phenol-containing wastewater is 0.23L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas was discharged from the outlet of the fixed bed reactor, and passed through the heat exchanger and the gas-liquid separator in sequence. The COD in the obtained condensate was 58.2 mgO ₂ /L, and the total phenol concentration was 0.39 mg/L. The VOCs of 19.5mg/m ³ .

Example 3

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 26000mgO ₂ /L, and the total phenol concentration is 2570mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is PdO/β molecular sieve, the loading amount of PdO is ₂ %, and the loading amount is 40g. The catalyst is prepared by spray drying method. After immersing 900 g of β molecular sieve in the above-mentioned aqueous solution for 12 h, add 333 g of silica sol (30% SiO ₂ content), stir evenly, spray shape in a spray dryer, dry at 120 ° C, calcinate at 550 ° C for 3 h, and the catalyst particle size is 60 ~200 μm. The deep oxidation catalyst loaded in the fixed bed reactor is Co ₂ O ₃ /white clay, and the loading amount of Co ₂ O ₃ is 10%. The catalyst is prepared by the mixing rolling method. The preparation method is: 350.6g Co(NO ₃ ) ₂ ·6H ₂ O Dissolved in 300ml of water, mixed with 1000g of clay and rolled evenly, then extruded into an extruder, dried at 120°C, calcined at 550°C for 3 hours, and the catalyst particle size was 2-4mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.18MPa, the catalytic cracking oxidation reaction temperature was 380°C, and the deep oxidation reaction temperature was 377°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 480L/(kg _{cat, cyclone fluidized bed} h), and the air feed tangentially entering from the enlarged section of the cyclone fluidized bed reactor is 120L/(kg _{cat, cyclone fluidized bed} ·h), and the feed of phenol-containing wastewater is 0.33L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas was discharged from the outlet of the fixed bed reactor, passed through the heat exchanger and the gas-liquid separator in turn, the COD in the obtained condensate was 32.8mgO ₂ /L, and the total phenol concentration in the condensate was 0.29mg/L, The VOCs in the non-condensable gas was 10.3 mg/m ³ .

Example 4

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 34000mgO ₂ /L, and the total phenol concentration is 5075mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is Cr ₂ O ₃ /Y molecular sieve, the loading amount of Cr ₂ O ₃ is 15%, and the loading amount is 40 g. The catalyst is prepared by spray drying method. (NO ₃ ) ₃ ·9H ₂ O was dissolved in 300 ml of water, 900 g of Y molecular sieve was immersed in the above aqueous solution for 12 hours, 500 g of aluminum sol (Al ₂ O ₃ content 20%) was added, stirred evenly, and sprayed in a spray dryer to form, Drying at 120°C, calcining at 550°C for 3h, the particle size of the catalyst is 60-200 μm. The deep oxidation catalyst loaded in the fixed bed reactor is NiO-CeO ₂ /SiO ₂ , the loading of NiO is 10%, and the loading of CeO ₂ is 5%. ₃ ) ₂ ·6H ₂ O, 126gCe(NO ₃ ) ₃ ·6H ₂ O were dissolved in 300ml of water, mixed with 1000g of silicon oxide powder evenly, then extruded in an extruder, dried at 120℃, 550℃ After calcination for 3h, the particle size of the catalyst is 2-4mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.12MPa, the catalytic cracking oxidation reaction temperature was 360°C, and the deep oxidation reaction temperature was 300°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 400L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 80L/(kg _{cat, cyclone fluidized bed} ·h), and the feed space velocity of phenol-containing wastewater is 0.46L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas was discharged from the outlet of the fixed bed reactor, passed through the heat exchanger and the gas-liquid separator in turn, the COD in the obtained condensate was 42.7mgO ₂ /L, and the total phenol concentration in the condensate was 0.38mg/L, The VOCs in the non-condensable gas was 12.1 mg/m ³ .

Example 5

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 46240mgO ₂ /L, and the total phenol content is 8034mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is Au ₂ O ₃ -MnO ₂ -Rb ₂ O/H-β molecular sieve, the loading amount of Au ₂ O ₃ is 2%, the loading amount of MnO ₂ is 12%, _The loading amount _{of Rb 2} O is ₁ %, the loading amount is 40 _g , and the catalyst is prepared by spray drying method. In 200ml of water, 900g of H-β molecular sieve was soaked in the above aqueous solution for 12h, then 500g of aluminum sol (Al ₂ O ₃ content of 20%) was added, stirred evenly, sprayed in a spray dryer, dried at 120° C., 550° C. After calcination for 3 hours, the particle size of the catalyst is 60-200 μm. The deep oxidation catalyst loaded in the fixed bed reactor is IrO ₂ -NiO-CuO/white clay, the loading amount of IrO ₂ is 1%, the loading amount of NiO is 4%, and the loading amount of CuO is 15%, and the catalyst is prepared by rolling method. , preparation method: Dissolve 23gH ₂ IrCl ₆ ·6H ₂ O, 155.7g Ni(NO ₃ ) ₂ ·6H ₂ O, 352g Cu(NO ₃ ) ₂ in 300ml water, mix with 1000g silicon oxide powder evenly, and squeeze It is extruded and formed in the machine, dried at 120 °C, calcined at 550 °C for 3 hours, and the catalyst particle size is 2-4 mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.24MPa, the catalytic cracking oxidation reaction temperature was 390°C, and the deep oxidation reaction temperature was 394°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 800L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 200L/(kg _{cat, cyclone fluidized bed} ·h), and the feed space velocity of phenol-containing wastewater is 0.05L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas is discharged from the outlet of the fixed bed reactor, and passes through the heat exchanger and the gas-liquid separator in turn. The obtained condensate contains 26.9 mgO ₂ /L, and the total phenol concentration in the condensate is 0.16 mg/L. The VOCs in the gas was 10 mg/m ³ .

Example 6

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 68000mgO ₂ /L, and the total phenol concentration is 876mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is PtO ₂ -Cr ₂ O ₃ /MCM-22 molecular sieve, the loading amount of PtO ₂ is 1%, the loading amount of Cr ₂ O ₃ is 14%, and the loading amount is 40g , the catalyst was prepared by spray drying. The preparation method was as follows: dissolve 18g HPtCl ₆ and 737.9g Cr(NO ₃ ) ₃ 9H ₂ O in 300ml water, immerse 900g MCM-22 molecular sieve in the above aqueous solution for 12h, add 500g aluminum The sol (Al ₂ O ₃ content of 20%) was stirred evenly, sprayed in a spray dryer, dried at 120° C., calcined at 550° C. for 3 hours, and the catalyst particle size was 60-200 μm. The deep oxidation catalyst loaded in the fixed bed reactor is CuO-CeO ₂ /white clay, the loading amount of CuO is 15%, and the loading amount of CeO ₂ is ₅ %. _2. Dissolve 126g Ce(NO ₃ ) ₃ ·6H ₂ O in 300ml of water, mix it with 1000g of silicon oxide powder evenly, then extrude it in an extruder, dry at 120℃, calcinate at 550℃ for 3h, and the catalyst particle size 2 to 4mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.18MPa, the catalytic cracking oxidation reaction temperature was 410°C, and the deep oxidation reaction temperature was 400°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 540L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 60L/(kg _{cat, cyclone fluidized bed} ·h), and the feed space velocity of phenol-containing wastewater is 0.15L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas was discharged from the outlet of the fixed bed reactor, passed through the heat exchanger and the gas-liquid separator in turn, the COD in the obtained condensate was 24.5mgO ₂ /L, and the total phenol concentration in the condensate was 0.09mg/L, The VOCs in the non-condensable gas was 7.9 mg/m ³ .

Example 7

The reaction adopts a cyclone fluidized bed-fixed bed series purification device, the COD of the phenol-containing wastewater is 100,000 mgO ₂ /L, and the phenol concentration is 10,000 mg/L. The catalytic cracking oxidation catalyst loaded in the cyclone fluidized bed reactor is MnO ₂ -PtO ₂ -Cr ₂ O ₃ /MCM-41, the loading of MnO ₂ is 10%, the loading of PtO ₂ is 1%, and the loading of Cr ₂ O ₃ The loading amount is 5%, and the loading amount is 40g. The catalyst is prepared by spray drying method. Preparation method: dissolve 267.3ml of 50% Mn(NO ₃ ) ₂ solution, 18gHPtCl ₆ , 263gCr(NO ₃ ) ₃ ·9H ₂ O In 300ml of water, 900g of MCM-41 molecular sieve was immersed in the above aqueous solution for 12h, then 500g of aluminum sol (Al ₂ O ₃ content 20%) was added, stirred evenly, sprayed in a spray dryer, dried at 120 ° C, 550 After calcination at ℃ for 3h, the particle size of the catalyst is 60-200 μm. The deep oxidation catalyst packed in the fixed bed reactor is _{Fe2O3 - CuO} -CeO2/alumina, the loading of _Fe2O3 is 15%, the loading of CuO is ₃ %, and the loading of CeO2 is ₂ % , the catalyst was prepared by the mixing rolling method. The preparation method was as follows: 759g Fe(NO ₃ ) ₃ ·9H ₂ O, 70.34g Cu(NO ₃ ) ₂ , 50.5g Ce(NO ₃ ) ₂ ·6H ₂ O were dissolved in 300ml water After the silicon oxide powder is uniformly mixed, it is extruded in an extruder, dried at 120°C, and calcined at 550°C for 3 hours. The particle size of the catalyst is 2-4 mm. The pressures of the cyclone fluidized bed reactor and the fixed bed reactor were kept the same, the operating pressure was 0.13MPa, the catalytic cracking oxidation reaction temperature was 450°C, and the catalytic oxidation reaction temperature was 400°C.

The air feed space velocity entering the fluidized section from the bottom of the cyclone fluidized bed is 1200L/(kg _{cat, cyclone fluidized bed} h), and the air feed velocity entering tangentially from the enlarged section of the cyclone fluidized bed reactor is 300L/(kg _{cat, cyclone fluidized bed} ·h), and the feed space velocity of phenol-containing wastewater is 0.6L/(kg _{cat, cyclone fluidized bed} ·h). The deeply oxidized gas is discharged from the outlet of the fixed bed reactor, and passes through the heat exchanger and the gas-liquid separator in turn. The COD in the obtained condensate is 15mgO ₂ /L, and the total phenol concentration in the condensate is 0.03mg/L. The VOCs in the condensed gas was 6.1 mg/m ³ .

Claims (8)

1. A method for purifying phenol-containing wastewater in the production process of catechol/hydroquinone is characterized by comprising the following steps:

(1) 1 air inlet is respectively arranged at the upper expanding section and the bottom of the cyclone fluidized bed reactor, two air streams are simultaneously introduced, the air is taken as an oxidant, one air stream enters the fluidizing section of the cyclone fluidized bed reactor from the bottom of the reactor, and the other air stream enters the reactor from the tangential direction of the expanding section; phenol-containing wastewater generated in the process of producing o/hydroquinone through phenol hydroxylation is added into a fluidized section of a cyclone fluidized bed reactor from the top of the cyclone fluidized bed reactor and is subjected to catalytic crackingUnder the action of the de-oxidation catalyst, organic matters in the wastewater and air undergo catalytic cracking oxidation reaction; wherein the chemical oxygen demand of the phenolic wastewater is 1000-100000 mgO₂L; the total phenol concentration in the phenol-containing wastewater is 100-10000 mg/L; the reaction pressure of the catalytic cracking oxidation reaction is 0.1-0.25 MPa, and the reaction temperature is 300-450 ℃;

(2) gas generated after catalytic cracking oxidation enters a fixed bed reactor connected with the cyclone fluidized bed reactor in series from the top, and is subjected to deep oxidation reaction under the action of a deep oxidation catalyst;

(3) and discharging the deeply oxidized gas from an outlet of the fixed bed reactor, sequentially passing through a heat exchanger and a gas-liquid separator, feeding the obtained condensate into a rain drainage system, and directly discharging the non-condensable gas in an emptying manner.

2. The method according to claim 1, wherein the total phenol concentration is the total concentration of phenol, hydroquinone, catechol, and resorcinol in the wastewater.

3. The method for purifying the phenol-containing wastewater in the production process of o/hydroquinone as claimed in claim 1, wherein in the step (1), the feeding space velocity of the phenol-containing wastewater is 0.05-0.6L/(kg)_{cat, gas cyclone fluidized bed}H) the total air feeding space velocity is 400-1500L/(kg)_{cat, gas cyclone fluidized bed}H), the volume ratio of the air entering the fluidization section from the bottom of the cyclone fluidized bed reactor to the air entering the expansion section tangentially is 9/1-2/1.

4. The method for purifying phenol-containing wastewater in the production process of o/hydroquinone as claimed in claim 1, wherein the catalytic cracking oxidation catalyst is a metal oxide catalyst, 1 or not more than 3 of oxides of ruthenium, palladium, platinum, gold, rubidium, chromium and manganese is used as an active component, one of Y molecular sieve, ZSM-5, MCM-22, MCM-41, SBA-15 and beta molecular sieve is used as a carrier, and the loading capacity of the active component is 1-20%.

5. The method for purifying phenol-containing wastewater in the production process of o/hydroquinone as claimed in claim 1, wherein in the step (2), the reaction pressure of the deep oxidation reaction in the fixed bed reactor is kept consistent with the pressure of the cyclonic fluidized bed reactor, and the reaction temperature of the deep oxidation reaction is 300-400 ℃.

6. The method for purifying phenol-containing wastewater in an o/hydroquinone production process as claimed in claim 1, wherein the loading amount of the deep oxidation catalyst in the fixed bed reactor is the same as the mass of the catalytic cracking oxidation catalyst in the cyclonic fluidized bed reactor.

7. The method for purifying phenol-containing wastewater in the production process of o/hydroquinone as claimed in claim 1, characterized in that the deep oxidation catalyst is a metal oxide catalyst, 1 or not more than 3 of oxides of lanthanum, iron, cobalt, nickel, cerium, iridium and copper are used as active components, one of alumina, silica, activated clay and attapulgite is used as a carrier, and the loading amount of the active components is 10-20%.

8. A system for realizing the purification method of the phenol-containing wastewater in the production process of the catechol/hydroquinone as described in claim 1, which is characterized in that the purification system comprises a cyclone fluidized bed reactor, a fixed bed reactor, a heat exchanger and a gas-liquid separator which are connected in series in sequence; the cyclone fluidized bed reactor comprises a lower fluidized section and an upper expanding section, wherein a catalytic cracking oxidation catalyst is filled in the fluidized section, a tangential air inlet is formed in the expanding section of the cyclone fluidized bed reactor to realize tangential air inlet, an axial air inlet 1 is formed in the bottom of the cyclone fluidized bed reactor, and a wastewater inlet and a gas outlet are formed in the top of the cyclone fluidized bed reactor; the gas outlet of the cyclone fluidized bed reactor is connected with the gas inlet at the top of the fixed bed reactor, and the outlet at the bottom of the fixed bed reactor is connected with the heat exchanger.

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