A coal gasification ash water hardness removal and analysis system in coordination with waste brine and its application

Abstract

The present invention discloses a coal gasification ash water hardness removal and analysis system in coordination with waste brine and its application, the system comprises a pretreatment unit, an adsorption unit and an analysis liquid treatment unit, the pretreatment unit, the adsorption unit and the analysis liquid treatment unit are sequentially connected through pipelines; the adsorption unit comprises an adsorption device and a waste brine storage tank, the adsorption device is provided with a cation exchange resin, the waste brine storage tank is connected to the water inlet at the bottom of the adsorption device, the waste brine storage tank stores waste brine as a source of sodium ions of the cation exchange resin, and the top of the adsorption device is provided with a pipeline connected to the water inlet of the pretreatment unit. The system of the present invention is applied to the hardness removal and analysis of coal gasification ash water, and the waste brine in the chemical park is used as an analysis agent for the resin hardness removal device to perform supersaturated adsorption and replace the backwater before analysis, which can significantly reduce the concentration of ammonia nitrogen and organic matter in the analysis liquid, and greatly improve the operation efficiency of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and more specifically, to a coal gasification ash water hardness removal and analysis system in coordination with waste brine and an application thereof. Background Art

[0002] The process ash water produced in the production process of existing coal gasifiers has high suspended matter, colloids, solid particles, hardness, COD, ammonia nitrogen and other substances, and the temperature is relatively high, generally around 85°C. When the ash water is reused in the system, calcium ions and magnesium ions will gradually concentrate, eventually leading to serious blockage of the system. Even if a large amount of scale inhibitors and dispersants are added, the scaling problem cannot be solved. Scaling blockage often causes shutdown, affecting the long-term stable operation of the system. At the same time, the discharged ash water enters the downstream sewage biological treatment, causing blockage of the aeration plate, tank body and membrane, affecting the stable operation of the equipment.

[0003] At present, the commonly used methods for treating gray water in the industry are the double alkali method and the resin adsorption method. The double alkali method uses the joint reaction of calcium hydroxide or sodium hydroxide, sodium carbonate, etc. to convert the calcium and magnesium hardness in the water into insoluble substances to achieve the purpose of removing hardness. The double alkali method requires a large amount of acid and alkali to adjust the pH of the gray water, and the precipitated calcium and magnesium insoluble substances will adhere to the surface of the agitator and the tank body, which requires frequent cleaning to ensure the normal operation of the equipment, which is costly and time-consuming.

[0004] The resin adsorption method can remove calcium ions and magnesium ions in water more thoroughly. The resin adsorption method usually uses acid-base resin analyzers or brine resin analyzers. The operating cost of the resin adsorption method of the acid-base resin analyzer is very high. Although the operating cost of the resin adsorption method of the brine resin analyzer is relatively low, the brine consumption is large, and the resin analysis liquid needs to be further discharged to the downstream sewage treatment system and boiler for mixing and burning, and the processing cost is high. For example, Chinese patent application CN112320974A provides a raw salt dissolution system used in a coal gasification ash water de-hardening device, which includes a multi-stage salt tank, wherein the primary salt tank is used to prepare saturated brine, the secondary salt tank is used to precipitate the saturated brine, and the tertiary salt tank is used to transport the saturated brine to the coal gasification ash water de-hardening device. The saturated brine is transported from the primary salt tank to the secondary salt tank by overflow, and from the secondary salt tank to the tertiary salt tank. The above patent application CN112320974A provides a multi-stage salting tank to deliver saturated brine to the coal gasification ash water de-hardening device. The salting tank has a complex structure, occupies a large area, and requires a relatively high cost to prepare the saturated brine. Summary of the invention

[0005] Based on this, it is necessary to provide a coal gasification ash water hardness removal and analysis system and its application for the coordinated waste brine which is low-cost, recyclable and beneficial to energy conservation and emission reduction in response to the above-mentioned technical problems.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, a coal gasification ash water hardness removal and analysis system in cooperation with waste brine comprises a pretreatment unit, an adsorption unit and an analysis liquid treatment unit, wherein the pretreatment unit, the adsorption unit and the analysis liquid treatment unit are sequentially connected through pipelines;

[0008] The adsorption unit comprises an adsorption device and a waste brine storage tank, wherein the adsorption device is provided with a cation exchange resin, the waste brine storage tank is connected to a water inlet at the bottom of the adsorption device, the waste brine storage tank stores waste brine as a source of sodium ions of the cation exchange resin, and a pipeline is provided on the top of the adsorption device to connect with a water inlet of a pretreatment unit;

[0009] The analytical solution processing unit comprises a buffer tank, a treatment reactor and a reduction reactor, which are connected in sequence through pipelines, and a pipeline is also provided at the water outlet of the reduction reactor to connect with the water inlet of the buffer tank for reflux.

[0010] Furthermore, the cation exchange resin is a gel-type cation exchange resin with high selectivity for divalent cations and can withstand a temperature of 80°C.

[0011] Furthermore, the pretreatment unit includes a sedimentation tank, an ash water tank and a pretreatment device in sequence. The sedimentation tank, the ash water tank and the pretreatment device are connected in sequence through pipelines. A pipeline is led out from the bottom of the pretreatment device and connected to the adsorption device. A pipeline is provided on the top of the adsorption device and connected to the water inlet of the sedimentation tank.

[0012] Furthermore, the pipeline between the buffer tank and the treatment reactor and the pipeline between the treatment reactor and the reduction reactor are also connected to reagent pipelines respectively.

[0013] Furthermore, a backwash pipeline is provided between the top of the pretreatment device and the water inlet of the sedimentation tank.

[0014] In a second aspect, the coal gasification ash water hardness removal and analysis system in coordination with waste brine of the first aspect is used in the coal gasification ash water hardness removal and analysis.

[0015] Further, in the application, the hardness removal method includes the following steps:

[0016] S11, diluting the waste brine in the waste brine storage tank and passing it through the bottom of the adsorption device to activate the cation exchange resin in the adsorption device;

[0017] S12, coal gasification ash water is pretreated by passing through a settling tank, an ash water tank and a pretreatment device of a pretreatment unit in sequence;

[0018] S13, the pretreated coal gasification ash water enters the adsorption device from the top, and the calcium ions, magnesium ions and ammonium ions in the ash water are exchanged with the sodium ions on the cation exchange resin;

[0019] S14. When the hardness penetrates, continue to keep the gray water inlet adsorption for 1~2h;

[0020] S15, introducing tap water twice the volume of the cation exchange resin from the bottom of the adsorption device, and then displacing the gray water in the adsorption device to the front-stage sedimentation tank;

[0021] S16, diluting the waste brine in the waste brine storage tank and passing it through the bottom of the adsorption device so that the calcium ions and magnesium ions on the resin of the adsorption device are exchanged with the sodium ions in the waste brine.

[0022] Further, in step S11, the waste brine in the waste brine storage tank is diluted to a sodium chloride mass percentage concentration of 10%, and then the diluted waste brine twice the volume of the cation exchange resin is introduced from the bottom of the adsorption device, and the amount introduced per hour is not less than the volume of the resin; in step S13, the amount of gray water introduced into the adsorption device per hour is 5 times the volume of the cation exchange resin; in step S14, when the hardness of the gray water after adsorption is greater than 50 mg / L, the gray water is continued to be adsorbed for 1 to 2 hours, and the cation exchange resin treats 80 times the volume of gray water in a single cycle; in step S15, the adsorption is carried out from the adsorption device. The bottom of the adsorption device is introduced with tap water twice the volume of the cation exchange resin, and the amount introduced per hour is not less than the volume of the cation exchange resin; in step S16, the waste brine in the waste brine storage tank is diluted to a sodium chloride mass percentage concentration of 10%, and then the diluted waste brine twice the volume of the cation exchange resin is introduced from the bottom of the adsorption device, and the amount introduced per hour is not less than the volume of the cation exchange resin; tap water twice the volume of the cation exchange resin is continued to be introduced from the bottom of the adsorption device to continue to exchange with the residual waste brine, and the amount introduced per hour is not less than twice the volume of the cation exchange resin.

[0023] Furthermore, in the application, the parsing method includes the following steps:

[0024] S21, start the analysis operation, and the analysis liquid enters the buffer tank from the top of the adsorption device and is heated;

[0025] S22, the analytical solution enters the treatment reactor from the buffer tank, and sodium hypochlorite and hydrochloric acid are added from the reagent pipeline between the buffer tank and the treatment reactor to remove ammonia nitrogen and adjust the pH;

[0026] S23, the analytical solution after the ammonia nitrogen is removed from the treatment reactor enters the reduction reactor, and at the same time, sodium sulfite reagent is added through the reagent pipeline between the treatment reactor and the reduction reactor;

[0027] S24. The analytical liquid is reduced in a reduction reactor, and after removing the oxide precipitate generated in the reaction process, part of it flows back to the water inlet end of the buffer tank, and the rest is discharged into the sea for treatment.

[0028] Furthermore, in step S21, the analytical solution enters the buffer tank from the top of the adsorption device and is heated to 45° C.; in step S22, sodium hypochlorite with a mass percentage concentration of 12% is added according to a weight ratio of ammonia nitrogen to sodium hypochlorite of 1:9-11, and hydrochloric acid is added at the same time to adjust the pH of the analytical solution inlet water to maintain a weak acidity of 5-6; in step S25, the reflux ratio is set to 1-3.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The purpose of the present invention is to utilize the industrial chain advantages of the industrial park, cooperate with the waste brine of the chemical park as the analytical agent of the resin de-hardening device, perform supersaturated adsorption and replace the return water before analysis, and significantly reduce the concentration of ammonia nitrogen and organic matter in the analytical solution. At the same time, develop analytical solution treatment technology, and the analytical solution can be directly discharged into the sea after being treated to meet the standards. The present invention provides a new idea for the de-hardening analysis of ash water in coal gasification equipment, realizes deep de-hardening at a low cost, solves the scaling problem of the reuse system and the sewage treatment system, and greatly improves the operating efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the solutions in the present application or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a schematic diagram of the structure of the coal gasification ash water hardness removal and analysis system for coordinated waste brine treatment proposed by the present invention;

[0033] Explanation of the reference numerals: sedimentation tank 1, gray water tank 2, pretreatment device 3, adsorption device 4, waste brine storage tank 5, buffer tank 6, treatment reactor 7, reduction reactor 8, gray water pipeline 9, backwash pipeline 10, analysis pipeline 11, reagent pipeline 12. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0036] Example 1

[0037] Please refer to Figure 1 The present embodiment provides a coal gasification ash water hardness removal and analysis system in coordination with waste brine, which includes a pretreatment unit, an adsorption unit and an analysis liquid treatment unit; the pretreatment unit, the adsorption unit and the analysis liquid treatment unit are connected in sequence through pipelines, and the pipelines include an ash water pipeline 9 and an analysis pipeline 11.

[0038] Specifically, the pretreatment unit includes a sedimentation tank 1, an ash water tank 2 and a pretreatment device 3 in sequence. The sedimentation tank 1, the ash water tank 2 and the pretreatment device 3 are connected through an ash water pipeline 9. When in use, gasified ash water (solid content 1% to 3%) enters the sedimentation tank 1. After sufficient sedimentation, the ash water overflows from the top of the ash water tank 2 and is stored in the ash water tank 2.

[0039] Furthermore, an ash water pump is provided in the ash water tank 2 to deliver the ash water in the ash water tank 2 to the pretreatment device 3. After the ash water enters the pretreatment device 3 from the top, impurities such as suspended solids and colloids are fully removed, and SS <1 mg / L when the water is discharged from the bottom of the pretreatment device 3; the treated coal gasification ash water flows out from the bottom of the pretreatment device 3 and enters the adsorption unit through the ash water pipeline 9;

[0040] Furthermore, the pretreatment device 3 is also provided with a gas-water backwashing function. Specifically, backwashing pipelines 10 are provided at the bottom and the top of the pretreatment device 3. Tap water enters the pretreatment device 3 from the bottom for backwashing. The sewage after backwashing returns from the top of the pretreatment device 3 through the backwashing pipeline 10 to the front sedimentation tank 1 for sedimentation together with the gasified ash water.

[0041] The adsorption unit includes an adsorption device 4 and a waste brine storage tank 5. The bottom water outlet of the pretreatment device 3 is connected to the top water inlet of the adsorption device 4 through a gray water pipeline 9. The adsorption device 4 is provided with a gel-type cation exchange resin. The gel-type cation exchange resin is activated at high temperature and adsorbs sodium ions. It can withstand a temperature of 80°C and has high selectivity for divalent cations in the gray water. After the gray water enters the adsorption device 4, the gel-type cation exchange resin can adsorb calcium ions, magnesium ions and ammonium ions in the gray water onto functional groups without adsorbing organic matter, and releases sodium ions. The gray water after de-hardening by the adsorption device 4 can be directly returned to the gasification system through the gray water pipeline 9 from the bottom water outlet of the adsorption device 4 for recycling.

[0042] Furthermore, a gray water pipeline 9 is provided on the top of the adsorption device 4 and connected to the water inlet of the sedimentation tank 1. A tap water inlet is also provided at the bottom of the adsorption device 4. When in use, the gray water is kept adsorbed until the hardness is penetrated, and the ammonia nitrogen in the resin bed will be fully replaced by calcium ions and magnesium ions. At this time, the gray water contains a large amount of ammonia nitrogen. After the adsorption operation is completed, the gray water is returned to the front sedimentation tank 1 through the gray water pipeline 9 to prevent too much ammonia nitrogen in the gray water from entering the analytical liquid treatment unit at one time.

[0043] Furthermore, the waste brine storage tank 5 is connected to the water inlet at the bottom of the adsorption device 4 through the analysis pipeline 11. The waste brine storage tank 5 stores waste brine. The waste brine storage tank 5 is provided with an analysis pump to pump the waste brine into the adsorption device 4 as a source of sodium ions for the gel-type cation exchange resin, thereby reducing the operating cost of resin analysis. Furthermore, the waste brine is derived from by-product brine from the industrial park, and contains sodium chloride at a mass percentage concentration of 15-20%. The waste brine is diluted as needed and then enters the adsorption device 4, which is environmentally friendly and energy-saving.

[0044] The analytical solution treatment unit includes a buffer tank 6, a treatment reactor 7 and a reduction reactor 8. The adsorption device 4, the buffer tank 6, the treatment reactor 7 and the reduction reactor 8 are connected in sequence through the analytical pipeline 11. After the waste brine stored in the waste brine storage tank 5 enters the adsorption device 4 from the bottom of the adsorption device 4, the sodium ions replace the calcium ions and magnesium ions in the resin bed, and the analytical solution with calcium ions and magnesium ions is transported from the top water outlet of the adsorption device 4 to the buffer tank 6. Furthermore, a deaerator (not shown in the figure) is also provided at the top water outlet of the adsorption device 4, and the TOC in the analytical solution after adsorption and deoxygenation treatment is <15mg / L. Furthermore, a heating device is provided in the buffer tank 6, which can heat the analytical solution, and at the same time, the instantaneous concentration change of the analytical solution can be reduced through the buffer tank 6, so that the fluctuation range of the ammonia nitrogen concentration entering the subsequent treatment reactor 7 is less than 5%. The heated analytical liquid enters the treatment reactor 7 from the buffer tank 6, and sodium hypochlorite is added to fully react to remove ammonia nitrogen in the analytical liquid. Then the analytical liquid enters the reduction reactor 8, and the oxide precipitate generated in the reaction process is removed in the reduction reactor 8. The analytical liquid after treatment is finally discharged into the sea through the outlet water of the reduction reactor 8.

[0045] Furthermore, the water outlet of the reduction reactor 8 is also provided with a desorption pipeline 11 to return part of the effluent to the water inlet of the buffer tank 6, thereby reducing the impact of the ammonia nitrogen concentration of the inlet water.

[0046] Furthermore, the analysis pipeline 11 between the buffer tank 6 and the treatment reactor 7 and the analysis pipeline 11 between the treatment reactor 7 and the reduction reactor 8 are also connected to a reagent pipeline 12, through which reagents are added to adjust the pH value of the analysis solution or to reduce the oxidized precipitate produced in the analysis solution into a soluble substance.

[0047] Furthermore, the treatment reactor 7 comprises three series-connected full mixed flow reactors, made of steel-lined PTFE, with volumes of 5m 3 .

[0048] Example 2

[0049] This embodiment provides a method for removing hardness from coal gasification ash water in conjunction with waste brine, which comprises the following steps:

[0050] S11, fill 50m into the adsorption device 4 3 The gel-type cation exchange resin is used to dilute the waste brine in the waste brine storage tank 5 to a sodium chloride mass percentage concentration of 10%, and then 100m3 of water is introduced from the bottom of the adsorption device 4. 3 , flow rate not less than 50m 3 / h, activate the resin, during which the volume of the resin will decrease by 5%;

[0051] S12, coal gasification ash water is pretreated by passing through the settling tank 1, ash water tank 2 and pretreatment device 3 of the pretreatment unit in sequence;

[0052] S13, the pre-treated coal gasification ash water is 3 / h flow rate enters the adsorption device 4 from the top, and the calcium ions, magnesium ions and ammonium ions in the grey water are exchanged with the sodium ions on the gel-type cation exchange resin, and the outlet water hardness is less than 10 mg / L;

[0053] S14, when the hardness of the ash water penetrates after adsorption (hardness> 50mg / L), continue to keep the ash water inlet adsorption for 1~2h, so that the ammonia nitrogen in the resin bed will be fully replaced by calcium ions and magnesium ions, 50m 3 Resin single cycle treatment 4000 m 3 Gray water, at this time, the calcium ions and magnesium ions of the resin bed are saturated, and ammonia nitrogen is more present in the gray water after adsorption;

[0054] S15, after fully replacing the ammonia nitrogen in the bed, introduce 100 m 3 Tap water, flow rate not less than 50m 3 / h, displacing the grey water in the adsorption device 4 to the front-stage sedimentation tank 1 to prevent ammonia nitrogen from entering the analytical liquid treatment unit in large quantities;

[0055] S16, dilute the waste brine in the waste brine storage tank 5 to a sodium chloride mass percentage concentration of 10%, and pass 100 m 3 , flow rate not less than 50m 3 / h, so that the calcium ions and magnesium ions on the gel-type cation exchange resin of adsorption device 4 are exchanged with sodium ions; 100 m 3The tap water and the residual waste brine continue to exchange, and the flow rate is not less than 100m 3 / h, after which the resin bed is filled with tap water; the analytical solution collected within 3 hours enters the analytical solution treatment unit for disposal, at which time the ammonia nitrogen concentration of the analytical solution is lower than 420 mg / L;

[0056] S17. Repeat the experiment four times and record various parameters of the analytical solution before it enters the analytical solution processing unit. The results are shown in Table 1.

[0057] Table 1: Parameters of the analytical solution before entering the analytical solution processing unit

[0058] Analysis solution water quality parameters Calcium adsorption capacity (g / L) pH TOC (mg / L) Ammonia nitrogen (mg / L) TDS (mg / L) Experiment 1 32.1 7.6 14.3 412 45236 Experiment 2 32.4 7.7 12.4 415 44986 Experiment 3 32.2 7.6 14.1 408 45610 Experiment 4 32.8 7.5 13.8 411 44673

[0059] Example 3

[0060] This embodiment provides a method for coal gasification ash water analysis in conjunction with waste brine, which includes the following steps:

[0061] S21, before the analytical solution treatment unit is turned on to inlet water, the treatment reactor 7 is filled with 80% of water;

[0062] S22, start the analysis operation, the analysis liquid enters the buffer tank 6 from the top of the adsorption device 4 and is heated to 45°C;

[0063] S23, the analytical solution enters the treatment reactor 7 from the buffer tank 6, and sodium hypochlorite is added from the analytical pipeline 11 between the buffer tank 6 and the treatment reactor 7. Sodium hypochlorite with a mass percentage concentration of 12% is added according to the ratio of ammonia nitrogen to sodium hypochlorite = 1:9~11 (weight ratio), and hydrochloric acid is added at the same time to adjust the pH of the analytical solution inlet water to maintain at a weak acidity of 5~6. Sodium hypochlorite and the analytical solution are fully mixed and then enter the treatment reactor 7;

[0064] S24, the analytical solution after the ammonia nitrogen is removed by the treatment reactor 7 enters the reduction reactor 8, and at the same time, the sodium sulfite reagent is added through the reagent pipeline 12 connected to the analytical pipeline 11 between the treatment reactor 7 and the reduction reactor 8, and the analytical solution and the sodium sulfite reagent are fully reacted in the reduction reactor 8;

[0065] In this step, since the resin adsorbs a small amount of divalent manganese, a small amount of manganese precipitate is generated in the analytical solution after oxidation by sodium hypochlorite. At the same time, the analytical solution after oxidation is acidic, so sodium sulfite is added to reduce the manganese precipitate and adjust the pH of the effluent to neutral;

[0066] S25, the analytical solution is reduced by the reduction reactor 8, and the oxide precipitate generated in the reaction process is removed, and part of it is refluxed to the water inlet end of the buffer tank 6, and the rest is discharged to the sea. In this step, the reflux ratio is set to 1-3 to reduce the impact of the ammonia nitrogen concentration at the water inlet end of the buffer tank 6;

[0067] S26. Repeat the experiment five times and record the parameters of the analytical solution before and after treatment by the analytical solution treatment unit. As shown in Table 2, 97% of the ammonia nitrogen is converted into nitrogen gas, the total nitrogen in the effluent is less than 15 mg / L, the ammonia nitrogen is less than 1 mg / L, and the TOC is less than 10 mg / L. The effluent water quality can meet the discharge into the sea standard.

[0068] Table 2: Parameters of the analytical solution before and after being treated by the analytical solution treatment unit

[0069] project Ammonia nitrogen: sodium hypochlorite (w / w) pH of the analytical solution in the reactor Reflux ratio Temperature (℃) Total nitrogen in influent (mg / L) Total nitrogen in effluent (mg / L) Ammonia nitrogen in effluent (mg / L) Outlet TOC (mg / L) Experiment 1 1:11 5.0 1 40 412 9.5 0.6 6.1 Experiment 2 1:9 6.0 1 40 389 14.2 0.5 8.4 Experiment 3 1:10 5.0 2 40 415 10.5 0.6 8.1 Experiment 4 1:10 5.0 3 40 405 8.1 0.8 7.3 Experiment 5 1:10 5.0 3 38 408 12.3 0.7 8.9

[0070] Comparative Example 1

[0071] This comparative example proposes a method for removing hardness of coal gasification ash water in conjunction with waste brine, which differs from Example 2 in that steps S14 and S15 are omitted, and when the hardness of the ash water penetrates after adsorption (hardness>50mg / L), the water adsorption of the ash water is stopped, and then the process directly proceeds to step S16.

[0072] The experiment was repeated four times. Table 3 records the parameters of the analytical solution before entering the analytical solution treatment unit in this comparative example. Since the ammonia nitrogen in the resin bed was not fully replaced by calcium ions and magnesium ions, the ammonia nitrogen concentration of the analytical solution was high. The ammonia nitrogen concentration of the analytical solution before entering the analytical solution treatment unit in this comparative example was close to 5 times that of Example 2, which greatly increased the difficulty of subsequent analytical treatment.

[0073] Table 3: Parameters of the analytical solution before entering the analytical solution processing unit

[0074] Analysis solution water quality parameters Calcium adsorption capacity (g / L) pH TOC (mg / L) Ammonia nitrogen (mg / L) TDS (mg / L) Experiment 1 29.7 7.6 412 2012 39986 Experiment 2 30.1 7.6 456 1988 40782 Experiment 3 30.5 7.7 413 2103 38908 Experiment 4 30.3 7.5 438 2034 40012

[0075] Comparative Example 2

[0076] This comparative example proposes a method for analyzing coal gasification ash water in conjunction with waste brine, which differs from Example 3 in that: in step 25, the analyzed liquid is reduced by a reduction reactor 8, and after removing the oxide precipitate generated in the reaction process, all of it is discharged into the sea for treatment, and no partial reflux is set.

[0077] The experiment was repeated 4 times. Table 4 records the parameters of the analytical solution before and after entering the analytical solution treatment unit in this comparative example. Since no reflux is set after the analytical solution is reduced by the reduction reactor 8, the impact of ammonia nitrogen concentration at the water inlet end of the buffer tank 6 is relatively large, the analytical solution in the treatment reactor 7 does not react thoroughly, and the total nitrogen and ammonia nitrogen concentrations of the effluent from the reduction reactor 8 are higher than those in Example 3.

[0078] Table 4: Parameters of the analytical fluid after being treated by the analytical fluid treatment unit before being discharged into the sea

[0079] project Ammonia nitrogen: sodium hypochlorite (w / w) pH of the analytical solution in the reactor Temperature (℃) Total nitrogen in influent (mg / L) Total nitrogen in effluent (mg / L) Ammonia nitrogen in effluent (mg / L) Outlet TOC (mg / L) Experiment 1 1：10 5.0 40 409 45 1.8 7.9 Experiment 2 1：10 5.5 40 414 41 1.6 8.1 Experiment 3 1：10 6.0 40 410 44 1.8 8.2 Experiment 4 1：10 6.0 40 418 50 1.9 6.8

[0080] Comparative Example 3

[0081] This comparative example proposes a method for analyzing coal gasification ash water in coordination with waste brine, which differs from Example 3 only in that the pH of the inlet water of the analysis solution in step S23 is maintained at a weak alkaline pH of 8-9.

[0082] The experiment was repeated 4 times. Table 5 records the parameters of the analytical solution before and after entering the analytical solution treatment unit in this comparative example. Since the pH of the analytical solution inlet water of the treatment reactor 7 was maintained at a weak alkaline state, ammonia nitrogen and sodium hypochlorite could not react completely, and the total nitrogen concentration of the effluent water exceeded 10 times that of Example 3, and could not meet the seawater discharge quality standard.

[0083] Table 5: Parameters of the analytical fluid after being treated by the analytical fluid treatment unit before being discharged into the sea

[0084] project Ammonia nitrogen: sodium hypochlorite (w / w) pH of the analytical solution in the reactor Reflux ratio Temperature (℃) Total nitrogen in influent (mg / L) Total nitrogen in effluent (mg / L) Ammonia nitrogen in effluent (mg / L) Outlet TOC (mg / L) Experiment 1 1：10 8.5 3 40 401 174 7.2 7.8 Experiment 2 1：10 9.0 3 40 409 193 6.4 8.1 Experiment 3 1：10 8.0 3 40 410 168 8.8 8.1 Experiment 4 1：10 8.5 3 40 418 186 5.2 6.9

[0085] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacement of some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. Application of a coal gasification ash water hardness removal and analysis system in conjunction with waste brine in coal gasification ash water hardness removal and analysis, characterized in that: The hardness removal and analysis system comprises a pretreatment unit, an adsorption unit and an analysis liquid processing unit, wherein the pretreatment unit, the adsorption unit and the analysis liquid processing unit are connected in sequence through pipelines; The adsorption unit comprises an adsorption device (4) and a waste brine storage tank (5), wherein the adsorption device (4) is provided with a cation exchange resin, the waste brine storage tank (5) is connected to a water inlet at the bottom of the adsorption device (4), the waste brine storage tank (5) stores waste brine as a source of sodium ions for the cation exchange resin, and a pipeline is provided at the top of the adsorption device (4) to connect to a water inlet of a pretreatment unit; The analytical liquid treatment unit comprises a buffer tank (6), a treatment reactor (7) and a reduction reactor (8); the buffer tank (6), the treatment reactor (7) and the reduction reactor (8) are connected in sequence through pipelines; the water outlet of the reduction reactor (8) is also provided with a pipeline connected to the water inlet of the buffer tank (6) for reflux; The cation exchange resin is a gel-type cation exchange resin with high selectivity for divalent cations and can withstand a temperature of 80°C; The pretreatment unit comprises a sedimentation tank (1), an ash water tank (2) and a pretreatment device (3) in sequence. The sedimentation tank (1), the ash water tank (2) and the pretreatment device (3) are connected in sequence through pipelines. A pipeline is led out from the bottom of the pretreatment device (3) and connected to an adsorption device (4). A pipeline is provided at the top of the adsorption device (4) and connected to a water inlet of the sedimentation tank (1). The pipeline between the buffer tank (6) and the treatment reactor (7) and the pipeline between the treatment reactor (7) and the reduction reactor (8) are also connected to reagent pipelines (12) respectively; A backwash pipeline (10) is provided between the top of the pretreatment device (3) and the water inlet of the sedimentation tank (1); The method for applying the hardness removal and analysis system to remove hardness from coal gasification ash water comprises the following steps: S11, diluting the waste brine in the waste brine storage tank (5) and introducing the waste brine from the bottom of the adsorption device (4) to activate the cation exchange resin in the adsorption device (4); S12, the coal gasification ash water is pretreated by passing through the sedimentation tank (1), the ash water tank (2) and the pretreatment device (3) of the pretreatment unit in sequence; S13, the pretreated coal gasification ash water enters the adsorption device (4) from the top, and the calcium ions, magnesium ions and ammonium ions in the ash water are exchanged with the sodium ions on the cation exchange resin; S14. When the hardness penetrates, continue to keep the gray water inlet adsorption for 1~2 hours to saturate the calcium ions and magnesium ions of the resin bed, and more ammonia nitrogen exists in the gray water after adsorption; S15, after fully replacing the ammonia nitrogen in the resin bed, introduce tap water twice the volume of the cation exchange resin from the bottom of the adsorption device (4), and then replace the gray water in the adsorption device (4) to the front-stage sedimentation tank (1) to prevent a large amount of ammonia nitrogen from entering the analytical liquid treatment unit; S16, diluting the waste brine in the waste brine storage tank (5) and introducing the waste brine into the bottom of the adsorption device (4) so ​​that the calcium ions and magnesium ions on the resin of the adsorption device (4) are exchanged with the sodium ions in the waste brine; The method for applying the hardness removal and analysis system to coal gasification ash water analysis comprises the following steps: S21, starting the analysis operation, the analysis liquid enters the buffer tank (6) from the top of the adsorption device (4) and is heated; S22, the analytical solution enters the treatment reactor (7) from the buffer tank (6), and sodium hypochlorite and hydrochloric acid are added from the reagent pipeline (12) between the buffer tank (6) and the treatment reactor (7) to remove ammonia nitrogen and adjust the pH. The pH of the analytical solution inlet is maintained at a weakly acidic pH of 5; S23, the analytical solution after the ammonia nitrogen is removed from the treatment reactor (7) enters the reduction reactor (8), and at the same time, sodium sulfite reagent is added through the reagent pipeline (12) between the treatment reactor (7) and the reduction reactor (8); wherein a small amount of manganese precipitate is generated in the analytical solution after the ammonia nitrogen is removed from the treatment reactor (7); S24, the analytical liquid is reduced in a reduction reactor (8), and after removing the oxide precipitate generated in the reaction process, part of it is returned to the water inlet end of the buffer tank (6), and the rest is discharged into the sea; In step S11, the waste brine in the waste brine storage tank (5) is diluted to a sodium chloride mass percentage concentration of 10%, and then the diluted waste brine twice the volume of the cation exchange resin is introduced from the bottom of the adsorption device (4), and the amount introduced per hour is not less than the volume of the resin; In step S21, the analytical solution enters the buffer tank (6) from the top of the adsorption device (4) and is heated to 45° C.; in step S22, sodium hypochlorite with a mass percentage concentration of 12% is added at a weight ratio of ammonia nitrogen to sodium hypochlorite of 1:9-11, and hydrochloric acid is added at the same time to adjust the pH of the analytical solution inlet water to maintain it at a weak acidity of 5; in step S24, the reflux ratio is set to 1-3.

2. The use according to claim 1, characterized in that: In step S13, the hourly amount of grey water introduced into the adsorption device (4) is 5 times the volume of the cation exchange resin; in step S14, when the hardness of the grey water after adsorption is greater than 50 mg / L, the grey water adsorption is continued for 1 to 2 hours, and the cation exchange resin processes 80 times the volume of grey water in a single cycle; in step S15, tap water twice the volume of the cation exchange resin is introduced from the bottom of the adsorption device (4), and the hourly amount introduced is not less than the volume of the cation exchange resin; in step S16, the waste brine in the waste brine storage tank (5) is diluted to a sodium chloride mass percentage concentration of 10%, and then the diluted waste brine twice the volume of the cation exchange resin is introduced from the bottom of the adsorption device (4), and the hourly amount introduced is not less than the volume of the cation exchange resin; and tap water twice the volume of the cation exchange resin is continued to be introduced from the bottom of the adsorption device (4) to continue to exchange with the residual waste brine, and the hourly amount introduced is not less than twice the volume of the cation exchange resin.

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