Hardness removal treatment method and system for coal gasification wastewater

Abstract

The invention provides a coal gasification wastewater hardness removal treatment method and system, the method can be used for a pretreatment method of coal gasification wastewater with high suspended solids and high hardness, and after the coal gasification wastewater is treated by the method, SSlt; the total hardness is 1t; the treated wastewater is basically free of hardness, and the scaling problem of a coal gasification device can be effectively relieved; in addition, the invention provides a treatment method of the anti-pollution filter material and a deep cleaning method of the filter material, the anti-pollution filter material subjected to chemical modification and plasma jet treatment does not scale and pollute, and hardened materials formed by intercepting suspended matters by the filter material can be removed in a manner of combining stirring, crushing and scrubbing devices; and the filter material can be always kept clean. The hardness removal treatment method for the coal gasification wastewater provided by the invention has the characteristic of relatively high treatment efficiency.

Description

Technical Field

[0001] The invention belongs to the field of applied chemical industry, and in particular relates to a method and system for removing hardness from coal gasification wastewater. Background Art

[0002] The wastewater from coal gasification units using the Texaco process has the characteristics of high hardness, high COD, and high ammonia nitrogen. Since the wastewater from coal gasification units is usually discharged and treated using biochemical processes such as SBR or A / O, high hardness wastewater can cause scaling of the transmission pipeline, scaling and blockage of the aeration plate in the biochemical pool, calcification of activated sludge, and blockage of the reverse osmosis membrane for water reuse. Therefore, it is necessary to remove the hardness of coal gasification wastewater.

[0003] At present, chemical hardness removal can be used to remove hardness from coal gasification wastewater. This method adds alkaline substances such as sodium hydroxide and sodium carbonate to the coal gasification wastewater to precipitate and separate calcium and magnesium ions in the coal gasification wastewater, thereby achieving the effect of hardness removal. However, this method has the disadvantages of large amount of reagents used and large sludge output.

[0004] To solve the above defects, some studies have used resin adsorption to remove calcium and magnesium from coal gasification wastewater. The resin adsorption method does not require the introduction of additional reagents into the coal gasification wastewater, does not produce sludge, and the water quality after treatment is also good. Due to the high content of suspended solids in coal gasification wastewater, filter media is required to filter and remove the suspended solids before resin adsorption. At present, high-hardness coal gasification wastewater often causes scaling of the filter media, poor filtration performance, and reduces the efficiency of coal gasification wastewater hardness removal treatment.

[0005] Therefore, developing a method for removing hardness from coal gasification wastewater with higher treatment efficiency has become a research direction. Summary of the invention

[0006] The invention provides a method for removing hardness from coal gasification wastewater, which has the characteristic of high treatment efficiency.

[0007] The present invention also provides a hardness removal treatment system for coal gasification wastewater, which has the characteristic of high treatment efficiency.

[0008] The present invention provides a method for removing hardness from coal gasification wastewater, which comprises the following steps: using anti-pollution filter material to sequentially filter and adsorb calcium and magnesium elements on the coal gasification wastewater to obtain de-hardened water;

[0009] The anti-pollution filter material is prepared using a method comprising the following process:

[0010] The AFM glass filter material is brought into contact with an alkaline substance to perform an alkaline etching treatment to obtain an alkaline etching product;

[0011] The alkali-etched product is brought into contact with an organic amine and then subjected to calcination treatment to obtain an organic amine pore-expanded product;

[0012] Performing plasma jet treatment on the organic amine pore-enlarged product to obtain the anti-pollution filter material;

[0013] The calcium and magnesium element adsorption treatment is performed using an ion exchange resin.

[0014] The method for removing hardness from coal gasification wastewater as described above, wherein the treatment temperature of the calcination treatment is 300-500° C. and the treatment time is 2-4 hours;

[0015] The treatment voltage of the plasma jet treatment is 8-12 kV, and the treatment time is 1-3 hours.

[0016] The method for removing hardness from coal gasification wastewater as described above, wherein, before the calcium and magnesium element adsorption treatment is performed, it also includes performing a first impurity removal adsorption treatment on the product obtained from the filtration treatment.

[0017] The method for removing hardness from coal gasification wastewater as described above, wherein the method further comprises using a modified ion exchange resin to perform the calcium and magnesium element adsorption treatment;

[0018] The modified ion exchange resin is prepared by a method comprising the following steps:

[0019] contacting the raw material cation exchange resin with 1,2-dichloroethane to perform a first swelling treatment to obtain a first swelling product;

[0020] contacting the first swollen product with an iron salt to obtain a first intermediate;

[0021] contacting the first intermediate with 1,2-dichloroethane and performing a second swelling treatment to obtain a second swelling product;

[0022] contacting the second swollen product with an amino acid porogen and isethionic acid to obtain the modified ion exchange resin;

[0023] The treatment temperature of the first swelling treatment is 70-90° C., and the treatment time is 5-15 hours;

[0024] The treatment temperature of the second swelling treatment is 70-90°C and the treatment time is 5-15h;

[0025] The iron salt is selected from at least one of ferric chloride and ferric sulfate;

[0026] The amino acid pore former is selected from at least one of glutamic acid, arginine, aspartic acid and leucine.

[0027] In the above-mentioned method for removing hardness from coal gasification wastewater, the raw material cation exchange resin is waste cation exchange resin from a desalination process.

[0028] The method for removing hardness from coal gasification wastewater as described above further includes regenerating the ion exchange resin after the calcium and magnesium element adsorption treatment using brine that has been sequentially treated with ozone and then subjected to a second impurity removal adsorption treatment to obtain regenerated wastewater.

[0029] The method for removing hardness from coal gasification wastewater as described above further includes deammoniation treatment of the regenerated wastewater.

[0030] The present invention also provides a system for removing hardness from coal gasification wastewater, which is used to perform any of the above-mentioned methods for removing hardness from coal gasification wastewater, and includes a filter tank and a calcium and magnesium element adsorption tank that are interconnected;

[0031] The filter tank includes the anti-pollution filter material, and the calcium and magnesium element adsorption tank includes the ion exchange resin.

[0032] The coal gasification wastewater hardness removal treatment system as described above, wherein it further comprises a filter material scrubber, the inlet of the filter material scrubber is connected to the filter material outlet of the filter tank, and the outlet of the filter material scrubber is connected to the filter material inlet of the filter tank;

[0033] The filter tank is provided with an anti-pollution filter material layer composed of the anti-pollution filter material, and the thickness of the anti-pollution filter material layer is 80-120 cm;

[0034] The filter material outlet of the filter tank is located below the filter material inlet of the filter tank.

[0035] In the above-mentioned coal gasification wastewater hardness removal treatment system, the filter tank further comprises a stirring paddle, the stirring paddle comprises a stirring blade, and the stirring blade is in contact with the anti-pollution filter material layer.

[0036] The coal gasification wastewater hardness removal treatment system as described above, wherein, further comprises a first impurity removal adsorption tank, wherein the filter tank is connected to the calcium and magnesium element adsorption tank via the first impurity removal adsorption tank; and / or,

[0037] It also includes an ozone treatment tank and a second impurity removal adsorption tank which are interconnected, wherein the outlet of the second impurity removal adsorption tank is connected to the regenerated water inlet of the calcium and magnesium element adsorption tank; and / or,

[0038] It also includes a regeneration wastewater tank and an ammonia evaporation tower. The inlet of the regeneration wastewater tank is connected to the regeneration wastewater outlet of the calcium and magnesium element adsorption tank, and the outlet of the regeneration wastewater tank is connected to the inlet of the ammonia evaporation tower.

[0039] The coal gasification wastewater hardness removal treatment system as described above, wherein, further comprises a filter water tank, wherein the inlet of the filter water tank is connected to the filter water outlet of the filter tank, the backwash water outlet of the filter water tank is connected to the backwash water inlet of the filter tank, and the filter water outlet of the filter water tank is connected to the filter water inlet of the calcium and magnesium element adsorption tank; and / or,

[0040] It also includes a de-hardening water tank, the inlet of which is connected to the de-hardening water outlet of the calcium and magnesium element adsorption tank; and / or,

[0041] It also includes a backwash water collection tank, the inlet of which is connected to the backwash water outlet of the filter tank.

[0042] The method for removing hardness from coal gasification wastewater provided by the present invention first uses an anti-pollution filter material that is not easy to scale to filter the coal gasification wastewater, and then uses a calcium and magnesium ion adsorption resin to remove calcium and magnesium ions in the coal gasification wastewater to obtain de-hardened water. The anti-pollution filter material makes the filtering device difficult to structure and has a long continuous working time. The method for removing hardness from coal gasification wastewater provided by the present invention has the characteristics of high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced one by one below. Obviously, the drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 A schematic diagram of a first coal gasification wastewater hardness removal treatment system provided by the present invention;

[0045] Figure 2 A schematic diagram of a second coal gasification wastewater hardness removal treatment system provided by the present invention;

[0046] Figure 3 This is a schematic diagram of a third coal gasification wastewater hardness removal treatment system provided by the present invention.

[0047] Description of reference numerals:

[0048] 101- filter tank;

[0049] 102-Calcium and magnesium element adsorption tank;

[0050] 103- filter material scrubber;

[0051] 104- stirring paddle;

[0052] 105-first impurity removal adsorption tank;

[0053] 106-Ozone treatment tank;

[0054] 107-second impurity removal adsorption tank;

[0055] 108-recycled wastewater tank;

[0056] 109- ammonia distillation tower;

[0057] 110-Filtered water pitcher;

[0058] 111-Hard water removal tank;

[0059] 112-Backwash water collection tank. DETAILED DESCRIPTION

[0060] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0061] At present, due to the high content of suspended matter in coal gasification wastewater, filter material is needed to filter and remove the suspended matter before resin adsorption. However, high-hardness coal gasification wastewater often causes scaling of the filter material, resulting in reduced hardness removal efficiency of coal gasification wastewater. The inventor analyzed that this is because the filter material used in the prior art is easily contaminated with dirt due to its surface properties, so a large amount of dirt accumulates and causes the filter material to scale and harden. Therefore, if the surface of the filter material can be modified, the filter material can be made less prone to scaling and hardening, thereby improving the hardness removal efficiency of coal gasification wastewater.

[0062] Based on this, the first aspect of the present invention provides a method for removing hardness from coal gasification wastewater, the method comprising the following steps: using an anti-pollution filter material to sequentially filter and adsorb calcium and magnesium elements on the coal gasification wastewater to obtain de-hardened water;

[0063] The anti-pollution filter material is prepared using a method comprising the following process:

[0064] The AFM glass filter material is brought into contact with an alkaline substance to perform an alkaline etching treatment to obtain an alkaline etching product;

[0065] The alkali-etched product is brought into contact with an organic amine and then calcined to obtain an organic amine pore-expanded product;

[0066] The organic amine pore expansion product is subjected to plasma jet treatment to obtain an anti-pollution filter material;

[0067] The calcium and magnesium adsorption treatment is performed using ion exchange resins.

[0068] The method for removing hardness from coal gasification wastewater provided by the present invention is used to remove hardness in coal gasification wastewater, that is, calcium and magnesium ions contained in coal gasification wastewater. The method first filters the coal gasification wastewater to remove suspended solids contained in the coal gasification wastewater, and then uses ion exchange resin to remove calcium and magnesium ions contained in the coal gasification wastewater, thereby completing the treatment and obtaining de-hardened water.

[0069] The present invention does not limit the specific type of ion exchange resin, as long as it meets the requirement of being able to adsorb calcium and magnesium ions. For example, in one embodiment, the resin can be selected from at least one of 001*7 type, HYA-10 type, and LSC-100 type cation exchange resins. At the same time, the present invention does not limit the source of the ion exchange resin. The ion exchange resin can be a new resin, a regenerated resin, or a product obtained by modifying waste cation exchange resin, as long as it meets the requirement of being able to adsorb calcium and magnesium ions.

[0070] Furthermore, in the above process, the anti-pollution filter material is obtained by using AFM glass filter material as raw material and undergoing modification treatment. Specifically, the alkali etching treatment can clean impurities on the surface of the filter material and partially dissolve the silicon element on the surface to prepare for subsequent processing procedures. The alkali etching treatment includes contacting the AFM glass filter material with an alkaline substance, wherein the alkaline substance includes at least one of sodium hydroxide and potassium hydroxide. It is understandable that in order to make the alkali etching treatment more efficient, the alkaline substance may also include water, that is, at least one of sodium hydroxide and potassium hydroxide is dissolved in water to form an aqueous solution for alkali etching treatment.

[0071] The present invention does not limit the treatment conditions of the alkali etching treatment. In one embodiment, the AFM glass filter material can be crushed to 0.25 mm to 0.5 mm and then mixed with a 2% by mass sodium hydroxide aqueous solution. The obtained mixed system is stirred at 80° C. for 4 hours, then washed with deionized water 6 to 8 times, and dried at 120° C. to obtain an alkali etching product.

[0072] The process of calcining the alkali-etched product after contacting with the organic amine utilizes the property that the organic amine can react with the AFM glass filter material to increase the specific surface area of ​​the glass filter material, improve the filtration accuracy, and lower the SS of the effluent water. Among them, the organic amine is selected from at least one of ethanolamine and tetraethylammonium hydroxide. The present invention does not limit the specific processing conditions of the above process. In one embodiment, the alkali-etched product, ethanolamine, and tetraethylammonium hydroxide can be added to water in a mass ratio of 10:1:0.05 and stirred at 60°C for 12 hours, followed by washing with deionized water for 3 to 5 times, and then calcined at a temperature of 400°C for 3 hours in an air atmosphere to obtain an organic amine pore expansion product.

[0073] Plasma jet treatment of the organic amine pore expansion product specifically refers to contacting the plasma jet with the organic amine pore expansion product. This treatment can increase the zeta potential of the surface of the filter material, thereby improving the anti-pollution ability. The present invention does not limit the specific conditions of the plasma jet treatment. In one embodiment, the organic amine pore expansion product can be treated with a plasma jet using an array plasma jet device customized by the Institute of Metal Research, Chinese Academy of Sciences.

[0074] The method for removing hardness from coal gasification wastewater provided by the present invention uses an anti-pollution filter material with a large specific surface area and a high zeta potential to filter the coal gasification wastewater, and then uses an ion exchange resin to remove calcium and magnesium ions. Since the anti-pollution filter material is not easy to clog and form, the continuous filtration time is long, so the method for removing hardness from coal gasification wastewater provided by the present invention has the characteristics of high efficiency.

[0075] In one embodiment, in order to make the anti-pollution filter material have stronger anti-pollution performance, the treatment temperature of the calcination treatment can be controlled to be 300-500°C, and the treatment time can be 2-4 hours; further, the treatment voltage of the plasma jet treatment can be controlled to be 8-12 kV, the treatment frequency can be 8.8 kHz, and the treatment time can be 1-3 hours. Appropriate treatment conditions can make the anti-pollution filter material have a higher zeta potential, so that the surface has more negatively charged surface groups, and thus has stronger anti-pollution performance.

[0076] Furthermore, in a specific embodiment, before the calcium and magnesium element adsorption treatment is performed, the product obtained by the filtration treatment is also subjected to a first impurity removal adsorption treatment. The inventors have found that when the product obtained by the filtration treatment is directly subjected to the calcium and magnesium element adsorption treatment, the life of the ion exchange resin is often shortened. After research, the inventors found that this is because coal gasification wastewater often contains some iron elements, and the iron elements cannot be removed during the filtration treatment. When the iron elements come into contact with the ion exchange resin used to perform the calcium and magnesium element adsorption treatment, the iron elements will occupy or block the active sites of the ion exchange resin, resulting in a shortened life of the ion exchange resin. Therefore, before the calcium and magnesium element adsorption treatment is performed, the product obtained by the filtration treatment is subjected to a first impurity removal adsorption treatment, which can remove the iron elements, thereby extending the life of the ion exchange resin used for the calcium and magnesium element adsorption treatment, and thus the hardness removal treatment method for coal gasification wastewater provided by the present invention has higher efficiency and lower cost.

[0077] In one embodiment, the first metal element removal treatment is performed using a strong acid ion exchange resin, such as D001 type resin. When this type of resin comes into contact with water containing iron elements, it can adsorb the iron elements in the water.

[0078] Furthermore, in order to make the hardness removal treatment method of coal gasification wastewater provided by the present invention have a lower cost, in one embodiment, it also includes using a modified ion exchange resin to perform calcium and magnesium element adsorption treatment;

[0079] The modified ion exchange resin is prepared by a process comprising the following steps:

[0080] contacting the raw material cation exchange resin with 1,2-dichloroethane to perform a first swelling treatment to obtain a first swelling product;

[0081] contacting the first swollen product with an iron salt to obtain a first intermediate;

[0082] contacting the first intermediate with 1,2-dichloroethane and performing a second swelling treatment to obtain a second swelling product;

[0083] contacting the second swollen product with an amino acid porogen and isethionic acid to obtain a modified ion exchange resin;

[0084] The treatment temperature of the first swelling treatment is 70-90°C and the treatment time is 5-15h;

[0085] The treatment temperature of the second swelling treatment is 70-90°C and the treatment time is 5-15h;

[0086] The iron salt is selected from at least one of ferric chloride and ferric sulfate;

[0087] The amino acid pore-forming agent is selected from at least one of glutamic acid, arginine, aspartic acid and leucine.

[0088] contacting the raw material cation exchange resin with 1,2-dichloroethane to perform a first swelling treatment to obtain a first swelling product;

[0089] contacting the first swollen product with an iron salt to obtain a first intermediate;

[0090] contacting the first intermediate with 1,2-dichloroethane and performing a second swelling treatment to obtain a second swelling product;

[0091] contacting the second swollen product with an amino acid porogen and isethionic acid to obtain a modified ion exchange resin;

[0092] The treatment temperature of the first swelling treatment is 70-90°C and the treatment time is 5-15h;

[0093] The treatment temperature of the second swelling treatment is 70-90°C and the treatment time is 5-15h;

[0094] The iron salt is selected from at least one of ferric chloride and ferric sulfate;

[0095] The amino acid pore-forming agent is selected from at least one of glutamic acid, arginine, aspartic acid and leucine.

[0096] First, 1,2-dichloroethane is a cross-linking agent, which can increase the cross-linking degree of the resin and improve the stability of the resin. Therefore, using 1,2-dichloroethane for a first swelling treatment at a treatment temperature of 70-90°C and a treatment time of 5-15h, and a second swelling treatment at a treatment temperature of 70-90°C and a treatment time of 5-15h can further improve the stability of the raw material cation exchange resin.

[0097] Secondly, when the raw material cation exchange resin is contacted with at least one iron salt selected from ferric chloride and ferric sulfate, the iron salt as a cross-linking agent can cross-link the raw material cation exchange resin again, thereby providing more calcium and magnesium adsorption capacity; after the raw material cation exchange resin is contacted with the iron salt, when it is contacted with the amino acid porogen and hydroxyethyl sulfonic acid, the amino acid porogen and hydroxyethyl sulfonic acid can perform secondary pore formation and re-sulfonation on the resin, thereby increasing the surface area and the number of sulfonic acid groups of the raw material ion exchange resin, thereby further increasing the surface area and adsorption capacity of the resin, and obtaining a modified ion exchange resin. Among them, the raw material cation exchange resin can be selected from at least one of 001*7 type, HYA-10 type, and LSC-100 type cation exchange resin.

[0098] More specifically, the contacting of the raw cation exchange resin with the iron salt, the amino acid porogen and the isethionic acid can all be carried out in 1,2-dichloroethane.

[0099] In one embodiment, the raw material cation exchange resin is first contacted with 1,2-dichloroethane to undergo a first swelling treatment, and then 0.5-1.5% iron salt by mass of 1,2-dichloroethane is added to the 1,2-dichloroethane undergoing the first swelling treatment, and the temperature is raised to 80° C. to allow the iron salt to react with the raw material cation exchange resin for 8-12 hours. The raw material cation exchange resin obtained after the reaction with the iron salt is extracted with ethanol for 10-14 hours, and then contacted with 1,2-dichloroethane again for a second swelling treatment, and then 0.005-0.02% of the mass of 1,2-dichloroethane amino acid porogen is added to the 1,2-dichloroethane subjected to the second swelling treatment, and the reaction is carried out at 40-60° C. for 4 hours, and then 0.5-1.5% of the mass of 1,2-dichloroethane is added to the reaction system. The temperature is raised to 80° C. and the reaction is carried out for 8-12 hours. Finally, it is washed 10 times with a 5% sodium chloride solution to make the washing liquid neutral, and then extracted with ethanol for 4 hours to finally obtain a modified ion exchange resin.

[0100] It is understandable that in order to further improve the performance of the modified ion exchange resin, in one embodiment, before the raw cation exchange resin is contacted with 1,2-dichloroethane, the raw cation exchange resin is also subjected to acid washing and alkaline washing with hydrochloric acid solution and sodium hydroxide aqueous solution, respectively, to remove organic matter, microorganisms, inorganic salts and other pollutants on the surface of the raw cation exchange resin.

[0101] In one embodiment, the raw material cation exchange resin refers to an ion exchange resin with calcium and magnesium adsorption function that is replaced and eliminated during the production process. The above method can restore part of the calcium and magnesium adsorption function of the waste cation exchange resin, so that it can continue to be used for calcium and magnesium adsorption treatment, thereby reducing the cost of the hardness removal treatment method for coal gasification wastewater provided by the present invention. More specifically, the raw material cation exchange resin is a waste cation exchange resin from a desalination process.

[0102] In one embodiment, the method for removing hardness from coal gasification wastewater provided by the present invention further comprises regenerating the ion exchange resin after the calcium and magnesium element adsorption treatment using brine that has been sequentially treated with ozone and then subjected to a second impurity removal adsorption treatment to obtain regenerated water.

[0103] After the calcium and magnesium adsorption treatment, the ion exchange resin needs to be regenerated to restore the adsorption capacity. In order to further reduce the hardness of the coal gasification wastewater provided by the present invention, brine can be used as a raw material to regenerate the ion exchange resin. Brine is usually wastewater containing 8-20% sodium chloride by mass, TOC <15mg / L, and may contain organic matter and metal elements such as Fe, Mn, and Ti. Therefore, before using brine for regeneration, it is necessary to first contact it with ozone to degrade the organic matter contained therein, and then perform a second impurity removal adsorption treatment. The second impurity removal adsorption treatment includes using a strong acid ion exchange resin to adsorb the metal elements such as Fe, Mn, and Ti contained therein, and the resulting treated water is used to regenerate the ion exchange resin that performs the calcium and magnesium element adsorption treatment to obtain regenerated wastewater. During the regeneration process, the sodium ions in the treated water replace the Ca, Mg and other ions adsorbed on the adsorption groups of the ion exchange resin, so that the ion exchange resin is regenerated.

[0104] Specifically, in ozone treatment, the ozone dosage can be controlled to be 2-5 kg / m 3 The treatment time is 1h, and the TOC in the desalted water after ozone treatment is <8mg / L.

[0105] The second impurity removal adsorption treatment for the brine may use the same type of resin as the first impurity removal adsorption treatment.

[0106] The present invention does not limit the specific regeneration process of the ion exchange resin, and the commonly used regeneration process in the art can be used. In one embodiment, the above regeneration process includes the following three steps performed in sequence:

[0107] 1) Use desalted water at 2 bv / h to clean the ion exchange resin in the calcium and magnesium adsorption tank for 2 hours;

[0108] 2) Using a mixture of desalted water and brine to clean the ion exchange resin in the calcium and magnesium adsorption tank at 1 bv / h for 2 hours, the dilution ratio of desalted water to brine is 1:1-2;

[0109] 3) Use desalted water at 2 bv / h to clean the ion exchange resin in the calcium and magnesium adsorption tank for 2 hours.

[0110] Wherein, in step 1), the desalted water is directly subjected to the second metal ion adsorption treatment without undergoing ozone treatment, and after removing metal elements such as Fe, Mn, and Ti, the desalted water is contacted with the ion exchange resin in the calcium and magnesium element adsorption tank to replace the coal gasification wastewater remaining in the ion exchange resin, thereby reducing the concentration of organic matter and ammonia nitrogen in the regenerated wastewater, and the obtained wastewater is discharged into a sewage treatment plant for treatment;

[0111] In step 2), the desalted water is mixed with the ozone-treated brine and then subjected to a second metal ion adsorption treatment. After removing metal elements such as Fe, Mn, and Ti, the brine is contacted with the ion exchange resin in the calcium and magnesium adsorption tank. In this process, the brine regenerates the ion exchange resin, displacing the residual organic matter, ammonia nitrogen, and calcium and magnesium elements adsorbed by the ion exchange resin. The desalted water is used to dilute and adjust the brine concentration and reduce the amount of brine used. The regenerated wastewater obtained in this process is deammonified;

[0112] In step 3), the desalted water is not subjected to ozone treatment, but directly subjected to the second metal ion adsorption treatment, and after removing metal elements such as Fe, Mn, and Ti, it contacts the ion exchange resin in the calcium and magnesium element adsorption tank. The function of inputting the desalted water after the salt water is to wash away the salt in the ion exchange resin and prevent the salt from entering the hard water. The ion exchange resin is regenerated, and the regenerated wastewater obtained enters the 109-ammonia distillation tower for deammoniation treatment.

[0113] In a more specific embodiment, the method for removing hardness from coal gasification wastewater provided by the present invention also includes deamination treatment of the regenerated wastewater. The regenerated wastewater contains calcium ions and magnesium ions from the ion exchange resin and ammonium salts from the coal gasification wastewater. Deamination treatment of the regenerated wastewater can remove the ammonium salts contained therein, thereby meeting the emission standards. In one embodiment, the deamination treatment includes adjusting the pH value of the regenerated wastewater to greater than 11, and entering an ammonia evaporation tower for deamination treatment; the ammonia evaporation tower adopts a flow-through tray, and the number of trays is greater than or equal to 30. A pH value greater than 11 helps the nitrogen element in the resin regeneration liquid to be converted into ammonia and then removed. The ammonia evaporation tower adopts a flow-through tray, and the number of trays is greater than or equal to 30 to obtain a better deamination effect.

[0114] The second aspect of the present invention provides a hardness removal treatment system for coal gasification wastewater, the system comprising a filter tank and a calcium and magnesium element adsorption tank which are interconnected; the filter tank comprises an anti-pollution filter material, and the calcium and magnesium element adsorption tank comprises an ion exchange resin.

[0115] Figure 1 A schematic diagram of a first coal gasification wastewater hardness removal treatment system used in the coal gasification wastewater treatment method provided by the present invention, as shown in FIG. Figure 1 As shown, the device includes a filter tank 101 and a calcium and magnesium adsorption tank 102 which are interconnected. Specifically, the filtered water outlet of the filter tank 101 is connected to the filtered water inlet of the calcium and magnesium adsorption tank 102. The filter tank 101 is provided with an anti-pollution glass filter material, which has a certain stacking thickness and constitutes an anti-pollution filter material layer; the calcium and magnesium adsorption tank 102 is provided with an ion exchange resin for performing calcium and magnesium adsorption treatment to obtain de-hardened water.

[0116] It is understandable that, in one embodiment, in addition to the anti-pollution filter material layer, the filter tank 101 also includes a supporting layer disposed at the bottom of the anti-pollution filter material layer. The present invention does not limit the specific structure of the supporting layer, and commonly used filter materials in the art can be used, for example, glass sand with different particle sizes. More specifically, in a specific embodiment, the filter materials in the filter tank 101 are, from top to bottom: an anti-pollution filter material layer with a particle size of 0.25 to 0.5 mm and a thickness of 80 to 120 cm, glass sand with a particle size of 0.25 to 0.5 mm and a thickness of 80 cm, glass sand with a particle size of 0.4 to 0.8 mm and a thickness of 25 mm, and glass sand with a particle size of 1 to 2 mm and a thickness of 25 mm.

[0117] During the operation of the above system, the coal gasification wastewater enters the 101-filter tank and is filtered, and then enters the 102-calcium-magnesium adsorption tank through the filtered water outlet of the 101-filter tank and the filtered water inlet of the 102-calcium-magnesium adsorption tank in sequence, and undergoes calcium-magnesium adsorption treatment to obtain de-hardened water.

[0118] The coal gasification wastewater treatment device provided by the present invention uses a 101-filter tank including anti-pollution glass filter material to filter the coal gasification wastewater, and then uses a 102-calcium and magnesium element adsorption tank with ion exchange resin to remove calcium and magnesium elements. The 101-filter tank plate is scaled and the continuous operation time is long, so that the device has the characteristics of high treatment efficiency.

[0119] Figure 2 A schematic diagram of a second coal gasification wastewater hardness removal treatment system used in the coal gasification wastewater treatment method provided by the present invention, as shown in FIG. Figure 2 As shown, the device also includes a filter material scrubber 103, the inlet of the filter material scrubber 103 is connected to the filter material outlet of the filter tank 101, and the outlet of the filter material scrubber 103 is connected to the filter material inlet of the filter tank 101;

[0120] The thickness of the anti-pollution filter material layer is 80-120cm;

[0121] The filter material outlet of the filter tank is located below the filter material inlet of the filter tank;

[0122] 101- The filter outlet of the filter tank is located at 80-110% of the laminar fluidization height of the anti-pollution filter material;

[0123] 101-The filter media inlet of the filter tank is located 10 to 30 cm below the top of the anti-pollution filter media layer.

[0124] Among them, the fluidization height refers to the thickness of the anti-pollution filter material layer when it is in a fluidized state during the backwashing process. The filter material outlet of the 101-filter tank is located at 80-110% of the fluidization height of the top filter material of the 101-filter tank, which means that the filter material outlet of the 101-filter tank is located in the range of 20% fluidization height below the top of the anti-pollution filter material layer in the fluidized state to 10% fluidization height above the top of the anti-pollution filter material layer. The filter material inlet of the 101-filter tank is located 10-30 cm below the top of the anti-pollution filter material layer, and the elevation is lower than the filter material outlet of the 101-filter tank.

[0125] 103-Filter material scrubber is used to scrub the filter material in 101-filter tank. Through high-speed friction scrubbing, a small amount of blocky compaction existing in the long-term operation of the filter material is dispersed and broken to maintain the cleanliness of the filter material layer. Specifically, first, the filtered water (i.e., the product obtained by filtering the coal gasification wastewater) enters the 101-filter tank through the backwash water inlet of the 101-filter tank, so that the anti-pollution filter material layer is in a fluidized state; the filter material is fluidized to an expansion height of 100%, and the anti-pollution filter material in a fluidized state enters the 103-filter material scrubber through the filter material outlet of the 101-filter tank. The 103-filter material scrubber rotates at a speed of 100 to 300 rpm. Under the rotational friction of the 103-filter material scrubber, the dirt attached to the anti-pollution filter material falls off, and the fallen dirt is returned through the filter material inlet of the 101-filter tank along with the filtered water and the treated anti-pollution filter material, completing the scrubbing treatment, and the filtered water containing dirt leaves the 101-filter tank for separate treatment.

[0126] The present invention does not limit the specific structure of the 103-filter material scrubber, and a commonly used 103-filter material scrubber in the art can be used. In one embodiment, a cylindrical brush stick is used inside the 103-filter material scrubber, the brush stick has a diameter of 200 to 400 mm, and the brush stick material is one of nylon wire, stainless steel wire, and sisal.

[0127] Furthermore, the present invention does not limit the method of allowing the filter material to enter the filter material scrubbing device. In one embodiment, a centrifugal pump can be used to drive ( Figure 1 The present invention does not limit the specific location of the centrifugal pump, and it can be set in any pipeline between 103-filter material scrubber and 101-filter tank, that is, it can be set between the filter material outlet of 101-filter tank and the inlet of 103-filter material scrubber, and it can also be set between the outlet of 103-filter material scrubber and the filter material inlet of 101-filter tank.

[0128] Furthermore, if Figure 2 As shown, 101-filter tank also includes 104-stirring paddle, 104-stirring paddle includes stirring blades, and the stirring blades are in contact with the anti-pollution filter material layer. More specifically, in one embodiment, the lowest point of the stirring blade is located 150mm below the top of the anti-pollution filter material layer. The stirring blade extends into the anti-pollution filter material layer to a suitable depth, which is conducive to the effective stirring of the anti-pollution filter material, and further improves the efficiency while preventing scaling and consolidation. It is understandable that 104-stirring paddle can be driven by an electric motor.

[0129] The stirring paddle 104 may adopt any one of rake stirring and straight blade disc turbine. When the filtration pressure drop of the filter tank 101 reaches 0.05-0.1MPa, the stirring paddle 104 is turned on to break and disperse the compacted material formed on the top of the anti-pollution filter material layer. The stirring paddle speed is 50-120rpm, and the stirring and breaking time is 5-10min.

[0130] Figure 3 A schematic diagram of a third coal gasification wastewater hardness removal treatment system used in the coal gasification wastewater treatment method provided by the present invention, as shown in FIG. Figure 3 As shown, the first coal gasification wastewater treatment device provided by the present invention also includes 105-a first impurity removal adsorption tank, and 101-a filter tank is connected to 102-a calcium and magnesium element adsorption tank through 105-a first impurity removal adsorption tank. A strong acid ion exchange resin for adsorbing iron elements is arranged in 105-a first impurity removal adsorption tank, which is used to perform metal element adsorption treatment on the product obtained by the filtration treatment. Specifically, the product obtained by the filtration treatment enters 105-a first impurity removal adsorption tank to adsorb metal elements, and the adsorbed product enters 102-a calcium and magnesium element adsorption tank to adsorb calcium and magnesium elements. Better adsorption effect can be obtained by controlling the wastewater flow rate in 105-a first impurity removal adsorption tank to 20-30 m / h.

[0131] Furthermore, it also includes 106-ozone treatment tank and 107-second impurity removal adsorption tank which are interconnected, and the outlet of 107-second impurity removal adsorption tank is connected to the regenerated water inlet of 102-calcium and magnesium element adsorption tank. 106-ozone treatment tank is used to treat the salt water with ozone, and 107-second impurity removal adsorption tank is provided with the same type of resin as 105-first impurity removal adsorption tank, which is used to treat the salt water with or without ozone treatment with metal element adsorption, and remove metal elements such as Fe, Mn, and Ti. Specifically, when the salt water is treated with ozone and metal element adsorption in turn, it is first treated with ozone in 106-ozone treatment tank, and then enters 107-second impurity removal adsorption tank for metal element adsorption treatment, and then enters 102-calcium and magnesium element adsorption tank through the regenerated water inlet of 102-calcium and magnesium element adsorption tank, and the cation exchange resin provided therein is regenerated, and the impurities adsorbed by the cation exchange resin are removed to become regenerated wastewater.

[0132] In one embodiment, the regeneration process comprises the following three steps performed in sequence:

[0133] 1) Use desalted water (from the desalted water preparation device in the plant) to clean the ion exchange resin in the 102-calcium and magnesium element adsorption tank at 2 bv / h for 2 hours;

[0134] 2) Using a mixture of desalted water and brine to clean the ion exchange resin in the 102-calcium and magnesium element adsorption tank at 1 bv / h for 2 hours, the dilution ratio of desalted water to brine is 1:1-2;

[0135] 3) Use desalted water at 2 bv / h to clean the ion exchange resin in the 102-calcium and magnesium element adsorption tank for 2 hours.

[0136] Wherein, in step 1), the desalted water is not subjected to ozone treatment, but directly subjected to metal ion adsorption treatment, and after removing metal elements such as Fe, Mn, and Ti, the desalted water enters the 102-calcium-magnesium adsorption tank through the regenerated water inlet of the 102-calcium-magnesium adsorption tank, and contacts with the ion exchange resin in the 102-calcium-magnesium adsorption tank, displacing the coal gasification wastewater remaining in the ion exchange resin, reducing the concentration of organic matter and ammonia nitrogen in the regenerated wastewater, and the obtained wastewater is discharged into a sewage treatment plant for treatment;

[0137] In step 2), the desalted water is mixed with the ozone-treated brine and then subjected to metal ion adsorption treatment. After removing metal elements such as Fe, Mn, and Ti, the desalted water enters the 102-calcium-magnesium adsorption tank from the regenerated water inlet of the 102-calcium-magnesium adsorption tank and contacts the ion exchange resin in the 102-calcium-magnesium adsorption tank. In this process, the brine regenerates the ion exchange resin, displacing the residual organic matter, ammonia nitrogen, and calcium and magnesium elements adsorbed by the ion exchange resin. The desalted water is used to dilute and adjust the brine concentration and reduce the amount of brine used. The regenerated wastewater obtained in this process enters the 109-deamination tower for deamination treatment;

[0138] In step 3), the desalted water is not treated with ozone, but directly subjected to metal ion adsorption treatment. After removing metal elements such as Fe, Mn, and Ti, the desalted water enters the 102-calcium-magnesium adsorption tank from the regenerated water inlet of the 102-calcium-magnesium adsorption tank, and contacts the ion exchange resin in the 102-calcium-magnesium adsorption tank. The function of inputting the desalted water after the salt water is to wash away the salt in the ion exchange resin and prevent the salt from entering the hard water. The regenerated wastewater obtained enters the 109-ammonia distillation tower for deamination treatment.

[0139] It is worth noting that in the above process, desalted water enters through the pipeline between 106-ozone treatment tank and 107-second impurity removal adsorption tank, and flows to 107-second impurity removal adsorption tank.

[0140] Further, the hardness removal treatment system of coal gasification wastewater also includes 108-regeneration wastewater tank and 109-ammonia evaporation tower. The inlet of 108-regeneration wastewater tank is connected to the regeneration wastewater outlet of 102-calcium and magnesium adsorption tank, and the outlet of 108-regeneration wastewater tank is connected to the inlet of 109-ammonia evaporation tower. Among them, 108-regeneration wastewater tank is used to receive the regeneration wastewater generated during the regeneration treatment of 102-calcium and magnesium adsorption tank, and the regeneration wastewater enters 109-ammonia evaporation tower after temporary storage in 108-regeneration wastewater tank. 109-ammonia evaporation tower can remove ammonium salts contained in the regeneration wastewater through deamination treatment to meet the emission standards. In one embodiment, 109-ammonia evaporation tower adopts flow-through tower plates, and the number of tower plates is greater than or equal to 30. 109-ammonia evaporation tower with the above characteristics can obtain better deamination effect.

[0141] Depend on Figure 3 It can be known that the hardness removal treatment system for coal gasification wastewater provided by the present invention also includes 110-filter water tank, the inlet of 110-filter water tank is connected to the filter water outlet of 101-filter tank, the backwash water outlet of 110-filter water tank is connected to the backwash water inlet of 101-filter tank, and the filter water outlet of 110-filter water tank is connected to the filter water inlet of 102-calcium and magnesium adsorption tank. 110-filter water tank is used to contain the filter product obtained by filtering the coal gasification wastewater. On the one hand, the filter product can enter the 102-calcium and magnesium adsorption tank from the filter water outlet of 110-filter water tank through the filter water inlet of 102-calcium and magnesium adsorption tank for calcium and magnesium adsorption treatment, and on the other hand, it can enter the 101-filter tank from the backwash water outlet of 110-filter water tank through the backwash water inlet of 101-filter tank to backwash the filter material including the anti-pollution filter material in 101-filter tank.

[0142] In addition, the de-hardening treatment system for coal gasification wastewater provided by the present invention further comprises a de-hardening water tank 111, the inlet of which is connected to the de-hardening water outlet of the calcium and magnesium adsorption tank 102. The de-hardening water tank 111 is used to temporarily hold the de-hardening water for subsequent process treatment.

[0143] Furthermore, the system also includes a backwash water collection tank 112, the inlet of which is connected to the backwash water outlet of the filter tank 101. The backwash water collection tank 112 is used to collect wastewater generated by backwashing the filter tank 101 for subsequent process treatment.

[0144] The method for treating coal gasification wastewater provided by the present invention is further described below in conjunction with specific embodiments.

[0145] Sources of raw materials and equipment:

[0146] AFM glass filter material uses 0# filter material from Yixing Xinzhan Environmental Protection Company.

[0147] Ethanolamine, tetraethylammonium hydroxide, isethionic acid, glutamic acid, arginine, aspartic acid, and leucine were from Sinopharm Group Co., Ltd.

[0148] 1,2-Dichloroethane, sodium chloride, sodium hydroxide and hydrochloric acid were obtained from Wanhua Chemical's PVC and chlor-alkali plants.

[0149] The spent ion exchange resin was obtained from the desalination water station of Wanhua Chemical Environmental Technology.

[0150] The equipment in the coal gasification wastewater hardness removal treatment system comes from the gasification unit of Wanhua Chemical Fujian Industrial Park.

[0151] Example 1

[0152] The wastewater used in this example was taken from the outlet wastewater of the coal gasification black water sediment tank of the coal gasification device of Wanhua Chemical (Fujian) Co., Ltd. The wastewater treatment capacity was 80m 3 / h, the wastewater calcium ion content is 450mg / L, the magnesium ion content is 24mg / L, and the COD is 600mg / L.

[0153] This embodiment uses Figure 3 The coal gasification wastewater hardness removal treatment system shown in the figure treats the coal gasification wastewater. Figure 3 As shown, the system includes 101-filter tank, 102-calcium and magnesium adsorption tank, 103-filter material scrubber, 104-stirring paddle, 105-first impurity removal adsorption tank, 106-ozone treatment tank, 107-second impurity removal adsorption tank, 108-regeneration wastewater tank, 109-ammonia evaporation tower, 110-filter water tank, 111-hardness removal tank, 112-backwash water collection tank.

[0154] Among them, the filtered water outlet of 101-filter tank is connected with the filtered water inlet of 102-calcium-magnesium adsorption tank through 110-filter water tank, 105-first impurity removal adsorption tank in sequence, the hard water removal outlet of 102-calcium-magnesium adsorption tank is connected with the hard water removal outlet, the regenerated wastewater outlet of 102-calcium-magnesium adsorption tank is connected with the inlet of 108-regenerated wastewater tank, the outlet of 108-regenerated wastewater tank is connected with the inlet of 109-ammonia evaporation tower, and the drainage at the bottom outlet of 109-ammonia evaporation tower is connected to the sea discharge pipeline.

[0155] In addition, the ozone treatment tank 106 is connected to the regenerated water inlet of the calcium and magnesium element adsorption tank 102 through the second impurity removal adsorption tank 107.

[0156] In addition, the backwash water outlet of the filtration water tank 110 is connected to the backwash water inlet of the filtration tank 101, and the backwash water outlet of the filtration tank 101 is connected to the inlet of the backwash water collection tank 112.

[0157] In addition, there is a stirring paddle 104 in the 110-filter water tank, the filter material outlet of the 110-filter water tank is connected to the filter material inlet of the 103-filter material scrubber, the filter material inlet of the 110-filter water tank is connected to the filter material inlet of the 103-filter material scrubber, the filter material outlet of the 101-filter tank is located at 80% of the fluidization height of the anti-pollution filter material layer, and the filter material inlet of the 101-filter tank is located 20 cm below the top of the anti-pollution filter material layer.

[0158] 101-Filtration tank filling 10m 3 The anti-pollution filter material has a particle size of 0.25mm to 0.5mm, a filtration accuracy of 1μm, a filter material filling height of 800mm, and a filtration setting of 8m / h linear speed. 104-The stirring paddle extends 150mm into the anti-pollution filter material layer. At this time, the filter materials in the 101-filter tank are, from top to bottom: an anti-pollution filter material layer with a particle size of 0.25 to 0.5mm and a thickness of 80cm; glass sand with a particle size of 0.25 to 0.5mm and a thickness of 80cm; glass sand with a particle size of 0.4 to 0.8mm and a thickness of 25mm; glass sand with a particle size of 1-2mm and a thickness of 25mm.

[0159] The anti-pollution filter material is prepared by the following method:

[0160] The AFM glass filter material is crushed into 0.25 mm to 0.5 mm, and 2% NaOH is used for alkaline etching at 80° C. for 4 hours with stirring. After the reaction, it is washed with deionized water for 6 to 8 times and dried at 120° C. Subsequently, the dried filter material, ethanolamine and tetraethylammonium hydroxide are added into water in a mass ratio of 10:1:0.05 and stirred at 60° C. for 12 hours to perform organic amine pore expansion treatment, and then it is washed with deionized water for 3 to 5 times, calcined at 400° C. in an air atmosphere for 3 hours and then cooled to room temperature; subsequently, atmospheric pressure jet plasma is used for plasma jet treatment, the discharge voltage is 8 to 12 kV, the frequency is 8.8 kHz, and the treatment time is 3 hours to obtain an anti-pollution filter material.

[0161] The operating parameters of the 101-filter tank are controlled as follows: operating pressure 0.2MPa, filtration time 7h, backwash time 30min, the backwash steps are stirring time 5min, sedimentation 5min, water backwash 10min, forward wash 2min, scrubbing 8min, stirring speed 50rpm, the filter material is transported to the 103-filter material scrubber, and the outlet of the 103-filter material scrubber is connected to the filter material inlet 20cm below the top of the anti-pollution filter material layer; a cylindrical brush stick is used inside the 103-filter material scrubber, the brush stick diameter is 400mm, and the brush stick material is nylon wire.

[0162] 105-the first impurity removal adsorption tank and 107-the second impurity removal adsorption tank are each filled with 1m 3D001 strong acid ion exchange resin is used to adsorb metal elements in the wastewater, and the wastewater flow rate in the tank is 20m / h.

[0163] 102- Fill 20m3 of calcium and magnesium adsorption tank 3 The modified ion exchange resin adsorbs calcium and magnesium ions in the wastewater. The adsorption time for each cycle is 18 hours. Part of the treated wastewater is discharged to the biochemical system and the rest is returned to the gasification system.

[0164] The modified ion exchange resin was prepared by the following method:

[0165] Take the waste HYA-10 cation exchange resin eliminated from the cation bed for desalted water refining, add 5% hydrochloric acid to soak for 24 hours, and wash with 5% NaOH for 3 to 5 times, then wash with deionized water until the pH is 6 to 9 to remove impurities in the waste resin, soak the obtained cation exchange resin in 1,2-dichloroethane for 6 hours for the first swelling treatment, add 1% ferric chloride by mass of 1,2-dichloroethane to 1,2-dichloroethane at 50°C and stir for 1 hour, then heat to 80°C and react for 10 hours, after the reaction is completed, wash the resin with deionized water until the washing liquid is clear, then extract with ethanol for 12 hours to obtain to the post-crosslinked ion exchange resin; then 1,2-dichloroethane was added to the post-crosslinked ion exchange resin to soak for 2 hours for a second swelling treatment, then 0.01% of glutamic acid pore-forming agent by weight of 1,2-dichloroethane was added to 1,2-dichloroethane at 50° C., and the reaction was carried out for 4 hours, then 1% of hydroxyethyl sulfonic acid by weight of 1,2-dichloroethane was added to 1,2-dichloroethane, and the reaction was carried out at 80° C. for 10 hours, and finally washed 10 times with 5% sodium chloride solution, and then the resin washing liquid was washed with deionized water to be neutral, and finally extracted with ethanol for 40 hours to obtain a modified ion exchange resin.

[0166] During the operation of the above system, the coal gasification wastewater passes through the pipeline in sequence through 101-filter tank, 110-filter water tank, 105-first impurity removal adsorption tank, 102-calcium and magnesium element adsorption tank and then enters 111-hardness removal water tank, and the hardness-removed water enters the subsequent biochemical system or returns to the coal gasification system.

[0167] 102- The resin in the calcium and magnesium adsorption tank needs to be regenerated after being saturated. During the regeneration process, the salt water with a salt content of >10% and TOC <15mg / L is introduced into the 106-ozone treatment tank. Ozone is first introduced into the salt water to oxidize the TOC in the salt water. The ozone dosage is 5kg / m 3, the oxidation time is 1h, and the TOC after oxidation is <8mg / L. The oxidized brine enters the 107-second impurity removal adsorption tank to remove metal impurities in the brine to obtain regenerated water for the resin regeneration in the 102-calcium and magnesium adsorption tank. Specifically, the resin in the 102-calcium and magnesium adsorption tank is first washed with desalted water at 2bv / h for 2h, and then the resin is washed with brine diluted with desalted water at 1bv / h for 2h, and the dilution ratio of desalted water to brine is 1:2; finally, the desalted water is used to wash with 2bv / h for 2h.

[0168] The regenerated wastewater obtained after regeneration treatment has a Ca content of 9140 mg / L, ammonia nitrogen of 834 mg / L, and TOC of 9.5 mg / L. The regenerated wastewater is transported to the 109-ammonia evaporation tower through the 108-regeneration wastewater tank for treatment. 32% sodium hydroxide is used to adjust the pH of the regenerated wastewater to 12, and then enters the 109-ammonia evaporation tower. The 109-ammonia evaporation tower uses a flow-through tray with 30 trays for deammonification of the regenerated wastewater. The bottom outlet of the 109-ammonia evaporation tower is connected to the sea discharge pipeline, and the regenerated wastewater after deammoniation is discharged to the sea.

[0169] The anti-pollution filter material in the 101-filter tank needs to be backwashed regularly. During the backwashing process, the filtered water stored in the 110-filter water tank enters the 101-filter tank through the backwash water inlet of the 101-filter tank, so that the anti-pollution filter material is fluidized to an expansion height of 100%. The anti-pollution filter material in the fluidized state is transported to the 103-filter material scrubber through a high-speed centrifugal pump. Under the rotating friction of the 103-filter material scrubber at a speed of 300rpm, the pollution in the filter material is broken into suspended matter and returned to the 101-filter tank for removal through backwashing. The dirt and backwash water enter the 112-backwash water collection tank through the backwash water outlet of the 101-filter tank.

[0170] In the de-hardened water obtained in this embodiment, SS<3mg / L, total hardness<10mg / L, meeting the biochemical and system reuse acceptance indicators, backwashing 500 times in the 102-calcium and magnesium element adsorption tank, the filtration flux decayed by 1%, and after regeneration using brine that had been treated with ozone and pre-treated with the second metal element adsorption, the resin adsorption capacity in the 102-calcium and magnesium element adsorption tank recovered by 99.8%, and the resin adsorption regeneration life was>600 cycles, effectively alleviating the scaling problem of the coal gasification device; after the regenerated wastewater was treated with ammonia evaporation, ammonia nitrogen was <1mg / L, and TOC was <10mg / L, meeting the discharge requirements into the sea.

[0171] Example 2

[0172] The preparation method of the anti-pollution glass filter material and modified ion exchange resin used in this embodiment and the process flow used are consistent with those in Example 1, and only the wastewater source and operating parameters are adjusted. The wastewater used in this embodiment is the wastewater from the outlet of the coal gasification black water sediment tank of the coal gasification device of the Yantai Industrial Park of Wanhua Chemical Group Co., Ltd., and the wastewater treatment capacity is 90m 3 / h, wastewater calcium ion content 400mg / L, magnesium ion content 30mg / L, COD 700mg / L.

[0173] The regenerated wastewater obtained after regeneration treatment has a Ca content of 9140 mg / L, ammonia nitrogen of 834 mg / L, and TOC of 9.5 mg / L. The regenerated wastewater is transported to the 109-ammonia evaporation tower through the 108-regeneration wastewater tank for treatment. 32% sodium hydroxide is used to adjust the pH of the regenerated wastewater to 12, and then it enters the 109-ammonia evaporation tower. The 109-ammonia evaporation tower adopts a flow-through tower plate with 30 tower plates for deammonification of the regenerated wastewater.

[0174] After being treated by the present invention, ss<3mg / L, total hardness<10mg / L, the treated wastewater has basically no hardness, meeting the biochemical and system reuse acceptance indicators, backwashing 500 times in the 102-calcium and magnesium element adsorption tank, the filtration flux decays by 0.5%, and after regeneration using brine that has been treated with ozone and pre-treated with the second metal element adsorption, the resin adsorption capacity in the 102-calcium and magnesium element adsorption tank is restored to 99.1%, and the resin adsorption regeneration life is>550 cycles, which effectively alleviates the scaling problem of the coal gasification device; after the regeneration liquid is treated with ammonia evaporation, ammonia nitrogen is <1mg / L, TOC is <10mg / L, meeting the discharge requirements into the sea.

[0175] Comparative Example 1

[0176] The wastewater used in this comparative example was taken from the outlet wastewater of the coal gasification black water sludge tank of the coal gasification unit of Wanhua Chemical (Fujian) Company. The wastewater treatment capacity was 80m3 / h, the calcium ion content of the wastewater was 450mg / L, the magnesium ion content was 24mg / L, and the COD was 600mg / L.

[0177] The system used in this comparative example does not include 104-agitator blade and 103-filter material scrubber.

[0178] Fill 10m into 101-filter tank 3 Quartz sand filter material is used to replace the anti-pollution filter material. Its particle size is 0.4mm~0.8mm, the filter material filling height is 800mm, and the filtration is set to a linear speed of 8m / h.

[0179] The operating parameters of 101-filter tank are controlled as follows: operating pressure 0.2MPa, filtration time 7h, backwash time 30min, backwashing steps include air backwashing 10min, water backwashing 15min, and forward washing 5min; the SS of the coal gas wastewater obtained after filtration treatment is <10mg / L, the 101-filter tank is backwashed 500 times, and the filtration flux decays by 30%. This shows that when the system does not include 104-agitation paddle and 103-filter material scrubber, the performance of 101-filter tank decays quickly and cannot meet the long-term stable operation of coal gasification wastewater hardness removal.

[0180] 102- Fill 20m3 of calcium and magnesium adsorption tank 3 The HYA-10 cation exchange resin discarded from the desalting water station adsorbs calcium and magnesium ions in the wastewater. The adsorption time for each cycle is 10 hours, and the total hardness of the effluent is <30 mg / L. Part of the treated wastewater is discharged to the biochemical system, and the rest is returned to the gasification system.

[0181] Unpretreated brine was used as the resin regeneration agent, and the salt content of the brine was >10%. After the resin was saturated with adsorption, it was first washed with desalted water at 2 bv / h for 2 h, then washed with concentrated brine at 1 bv / h for 2 h, and finally washed with 2 bv / h for 2 h to complete the resin regeneration. After brine regeneration, the resin adsorption capacity recovered by 96.5%, and the resin adsorption regeneration life was >300 cycles. It can be seen that the capacity recovery rate and resin adsorption regeneration life in this comparative example are relatively low.

[0182] The regenerated wastewater obtained by regeneration treatment has a Ca content of 8100mg / L, ammonia nitrogen of 951mg / L, and TOC of 8.7mg / L. The regenerated wastewater is transported to the 109-ammonia evaporation tower for treatment. First, a 32% sodium hydroxide aqueous solution is used to adjust the pH of the regenerated wastewater to 12, and then enters the 109-ammonia evaporation tower. The 109-ammonia evaporation tower uses a flow-through tray with 30 trays. The regenerated wastewater is deammonified. After deammonification, the ammonia nitrogen of the regenerated liquid is less than 1mg / L, and the TOC is less than 10mg / L, which meets the requirements for discharge into the sea.

[0183] Comparative Example 2

[0184] The wastewater used in this example is the wastewater from the outlet of the coal gasification black water sediment tank of the coal gasification unit of the Yantai Industrial Park of Wanhua Chemical Group Co., Ltd. The wastewater treatment capacity is 90m 3 / h, wastewater calcium ion content 400mg / L, magnesium ion content 30mg / L, COD 700mg / L.

[0185] The system used in this comparative example does not include 104-agitator blade and 103-filter material scrubber.

[0186] Fill 10m into 101-filter tank 3Quartz sand filter material is used to replace the anti-pollution filter material. Its particle size is 0.4mm~0.8mm, the filter material filling height is 800mm, and the filtration is set to a linear speed of 9m / h.

[0187] The operating parameters of the 101-filter tank are controlled as follows: operating pressure 0.2MPa, filtration time 7h, backwash time 30min, the backwash steps are air backwashing 10min, water backwashing 15min, and forward washing 5min; the SS of the coal gas wastewater obtained after filtration treatment is <10mg / L, the 101-filter tank is backwashed 500 times, and the filtration flux is attenuated by 28%. This shows that when the system does not include 104-agitator and 103-filter material scrubber, the performance of the 101-filter tank decays quickly and cannot meet the long-term stable operation of coal gasification wastewater hardness removal.

[0188] 102- Fill 20m3 of calcium and magnesium adsorption tank 3 The HYA-10 cation exchange resin discarded from the desalination station adsorbs calcium and magnesium ions in the wastewater. The adsorption time for each cycle is 12 hours, and the total hardness of the effluent is <30 mg / L. Part of the treated wastewater is discharged to the biochemical system, and the rest is returned to the gasification system.

[0189] Unpretreated brine was used as the resin regeneration agent, and the salt content of the brine was >10%. After the resin was saturated with adsorption, it was first washed with desalted water at 2 bv / h for 2 h, then washed with concentrated brine at 1 bv / h for 2 h, and finally washed with 2 bv / h for 2 h to complete the resin regeneration. After brine regeneration, the resin adsorption capacity recovered by 95.3%, and the resin adsorption regeneration life was >280 cycles. It can be seen that the capacity recovery rate and resin adsorption regeneration life in this comparative example are relatively low.

[0190] After regeneration, the Ca content in the resin regeneration liquid is 8200 mg / L, the ammonia nitrogen is 911 mg / L, and the TOC is 9.2 mg / L. The regeneration liquid is transported to the 109-ammonia distillation tower for treatment. First, a 32% sodium hydroxide aqueous solution is used to adjust the pH of the regeneration wastewater to 12, and then it enters the 109-ammonia distillation tower. The 109-ammonia distillation tower adopts a cross-flow tower plate with 30 tower plates; the regeneration wastewater is deammonified; after deammoniation treatment, the ammonia nitrogen of the regeneration liquid is <1 mg / L, and TOC is <10 mg / L, which meets the requirements for discharge into the sea.

[0191] Test example

[0192] 1. The anti-pollution glass filter material used in Example 1, the quartz sand filter material used in Comparative Example 1, and the AFM glass filter material used to prepare the anti-pollution glass filter material used in Example 1 were taken and the specific surface area was tested using a BELSORP MINI X specific surface area tester of MICROTRACBEL. The test results are shown in Table 1.

[0193] Table 1 Filter material specific surface area data

[0194]

[0195] It can be seen from Table 1 that the anti-pollution glass filter material has a higher specific surface area than the quartz sand filter material and the AFM filter material.

[0196] 2. The anti-pollution glass filter material used in Example 1, the quartz sand filter material used in Comparative Example 1, and the AFM glass filter material used to prepare the anti-pollution glass filter material used in Example 1 were taken for zeta potential testing. The test results are shown in Table 2.

[0197] The test method is as follows:

[0198] The zeta potential of the filter material was tested using the SurPASS solid surface potential analyzer. Specifically, 1 mmol / L potassium chloride electrolyte was circulated through the sample pool containing the test sample to form a flow pressure difference, and the zeta potential was measured through the electrodes on both sides of the sample.

[0199] Table 2 Filter material ZETA potential data

[0200]

[0201] It can be seen from Table 2 that the anti-pollution glass filter material has a higher zeta potential than the quartz sand filter material and the AFM filter material.

[0202] 3. The anti-pollution glass filter material used in Example 1, the quartz sand filter material used in Comparative Example 1, and the AFM glass filter material used to prepare the anti-pollution glass filter material used in Example 1 were taken to perform filter material performance tests. The test results are shown in Table 3.

[0203] The test method is as follows:

[0204] Different types of filter media were loaded into the filter columns for filtration tests. Wastewater containing 50 mg / L SS was input into each filter column at a filtration linear speed of 10 m / h for filtration for 20 hours. The filtered water was taken out in each cycle for effluent SS test, and the effluent SS was filtered and enriched, and then the effluent SS particle size distribution was tested with a laser particle size distribution instrument. Subsequently, backwashing regeneration was carried out according to the backwashing conditions of each filter media. After regeneration, the filtration was repeated for 20 cycles, and then each filter media was taken out to test the mud content of the filter media.

[0205] Table 3 Comparison of filter material performance

[0206]

[0207] It can be seen from Table 3 that the anti-pollution glass filter material has higher filtration performance than the quartz sand filter material and the AFM filter material.

[0208] 4. The modified ion exchange resin used in Example 1, the waste HYA-10 cation exchange resin used to prepare the modified ion exchange resin, and the fresh HYA-10 cation exchange resin were respectively taken to perform resin performance tests. The test results are shown in Table 4.

[0209] The test method is as follows:

[0210] Take 100 ml of different types of resins and load them into adsorption columns. Introduce an aqueous solution containing 1000 mg / L calcium chloride into each resin column until each resin column is saturated with adsorption. Use 5% hydrochloric acid to regenerate the resin, and calculate the adsorption capacity of the corresponding resin based on the calcium ion concentration in the regeneration solution.

[0211] Table 4 Resin performance comparison

[0212] Resin Type Adsorption capacity (g / L) Waste HYA-10 cation exchange resin 21.6 Modified ion exchange resin 32.2 Fresh HYA-10 cation exchange resin 33.5

[0213] It can be seen from Table 4 that the modified ion exchange resin has a higher adsorption capacity than the waste resin.

[0214] Compared with the prior art, the present invention has the following beneficial effects:

[0215] First, the present invention provides a pretreatment method for coal gasification wastewater with high suspended matter and high hardness. After the coal gasification wastewater is treated by the present invention, the SS is <3 mg / L and the total hardness is <10 mg / L. The treated wastewater has basically no hardness, which can effectively alleviate the scaling problem of the coal gasification device.

[0216] Second, the present invention provides a method for treating anti-pollution filter material and a method for deep cleaning of filter material. The anti-pollution filter material itself will not be scaled and polluted after chemical modification and plasma jet treatment. The compaction formed by suspended matter retained by the filter material can be removed by a combination of stirring and crushing and a scrubbing device, thereby ensuring that the filter material always remains clean.

[0217] Third, the present invention provides a method for modifying waste ion exchange resins. By post-crosslinking, secondary pore formation and sulfonation treatment of the waste ion exchange resins, a modified ion exchange resin with high specific surface area and adsorption capacity is prepared for calcium and magnesium ion adsorption treatment.

[0218] Fourthly, the present invention provides a method of using brine as a resin regeneration agent, which uses brine as a resin regeneration agent after ozone oxidation and resin impurity removal, thereby reducing the risk of impurities in the brine contaminating the resin. In addition, compared with the common resin acid-base regeneration, the process of using brine regeneration is safer and simpler.

[0219] Finally, the present invention provides a method for discharging resin regeneration liquid into the sea, which uses ammonia evaporation to remove high ammonia nitrogen in the regeneration wastewater, solves the problem that high-salt and high-ammonia nitrogen wastewater cannot be treated biochemically, and achieves the standard discharge of resin regeneration liquid into the sea.

[0220] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for removing hardness from coal gasification wastewater, characterized in that: The method comprises the following steps: using anti-pollution filter material to sequentially filter and adsorb calcium and magnesium elements on coal gasification wastewater to obtain hard-free water; The anti-pollution filter material is prepared using a method comprising the following process: The AFM glass filter material is brought into contact with an alkaline substance to perform an alkaline etching treatment to obtain an alkaline etching product; The alkali-etched product is brought into contact with an organic amine and then subjected to calcination treatment to obtain an organic amine pore-expanded product; Performing plasma jet treatment on the organic amine pore-enlarged product to obtain the anti-pollution filter material; The calcium and magnesium element adsorption treatment is performed using an ion exchange resin.

2. The method for removing hardness from coal gasification wastewater according to claim 1, characterized in that: The calcination treatment has a treatment temperature of 300-500°C and a treatment time of 2-4h; The treatment voltage of the plasma jet treatment is 8-12 kV, and the treatment time is 1-3 hours.

3. The method for removing hardness from coal gasification wastewater according to claim 1 or 2, characterized in that: Before the calcium and magnesium element adsorption treatment is performed, the product obtained by the filtration treatment is subjected to a first impurity removal adsorption treatment.

4. The method for removing hardness from coal gasification wastewater according to any one of claims 1 to 3, characterized in that: It also includes using a modified ion exchange resin to perform the calcium and magnesium element adsorption treatment; The modified ion exchange resin is prepared by a method comprising the following steps: contacting the raw material cation exchange resin with 1,2-dichloroethane to perform a first swelling treatment to obtain a first swelling product; contacting the first swollen product with an iron salt to obtain a first intermediate; contacting the first intermediate with 1,2-dichloroethane and performing a second swelling treatment to obtain a second swelling product; contacting the second swollen product with an amino acid porogen and isethionic acid to obtain the modified ion exchange resin; The treatment temperature of the first swelling treatment is 70-90° C., and the treatment time is 5-15 hours; The treatment temperature of the second swelling treatment is 70-90°C and the treatment time is 5-15h; The iron salt is selected from at least one of ferric chloride and ferric sulfate; The amino acid pore former is selected from at least one of glutamic acid, arginine, aspartic acid and leucine.

5. The method for removing hardness from coal gasification wastewater according to claim 4, characterized in that: The raw material cation exchange resin is a waste cation exchange resin from a desalination process; and / or, It also includes regenerating the ion exchange resin after the calcium and magnesium element adsorption treatment using salt water that has been sequentially treated with ozone and second impurity removal and adsorption treatment to obtain regenerated wastewater; and / or, The method also includes deammoniation treatment of the regenerated wastewater.

6. A system for removing hardness from coal gasification wastewater for executing the method for removing hardness from coal gasification wastewater according to any one of claims 1 to 5, characterized in that: It includes a filter tank and a calcium and magnesium element adsorption tank which are interconnected; The filter tank includes the anti-pollution filter material, and the calcium and magnesium element adsorption tank includes the ion exchange resin.

7. The system for removing hardness from coal gasification wastewater according to claim 6, characterized in that: It also includes a filter material scrubber, the inlet of the filter material scrubber is connected to the filter material outlet of the filter tank, and the outlet of the filter material scrubber is connected to the filter material inlet of the filter tank; The filter tank is provided with an anti-pollution filter material layer composed of the anti-pollution filter material, and the thickness of the anti-pollution filter material layer is 80-120 cm; The filter material outlet of the filter tank is located below the filter material inlet of the filter tank.

8. The system for removing hardness from coal gasification wastewater according to claim 6 or 7, characterized in that: The filter tank further comprises a stirring paddle, wherein the stirring paddle comprises a stirring blade, and the stirring blade is in contact with the anti-pollution filter material layer.

9. The system for removing hardness from coal gasification wastewater according to any one of claims 6 to 8, characterized in that: It also includes a first impurity removal adsorption tank, and the filter tank is connected to the calcium and magnesium element adsorption tank through the first impurity removal adsorption tank; and / or, It also includes an ozone treatment tank and a second impurity removal adsorption tank which are interconnected, wherein the outlet of the second impurity removal adsorption tank is connected to the regenerated water inlet of the calcium and magnesium element adsorption tank; and / or, It also includes a regeneration wastewater tank and an ammonia evaporation tower. The inlet of the regeneration wastewater tank is connected to the regeneration wastewater outlet of the calcium and magnesium element adsorption tank, and the outlet of the regeneration wastewater tank is connected to the inlet of the ammonia evaporation tower.

10. The system for removing hardness from coal gasification wastewater according to any one of claims 6 to 9, characterized in that: It also includes a filtered water tank, the inlet of the filtered water tank is connected to the filtered water outlet of the filter tank, the backwash water outlet of the filtered water tank is connected to the backwash water inlet of the filter tank, and the filtered water outlet of the filtered water tank is connected to the filtered water inlet of the calcium and magnesium element adsorption tank; and / or, It also includes a de-hardening water tank, the inlet of which is connected to the de-hardening water outlet of the calcium and magnesium element adsorption tank; and / or, It also includes a backwash water collection tank, the inlet of which is connected to the backwash water outlet of the filter tank.

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