An apparatus and method for increasing gypsum production from desulfurization wastewater

Abstract

The application relates to the technical field of sewage treatment, and discloses a device and method for improving the gypsum yield in desulfurization wastewater. The device comprises a separation unit, a conditioning unit and a dehydration unit. The method comprises the following steps: (1) performing separation treatment on desulfurization thick slurry to obtain desulfurization wastewater and gypsum sludge I; (2) performing conditioning reaction on a conditioning agent, recovered gypsum and the desulfurization wastewater to obtain gypsum sludge II; and (3) performing dehydration treatment on the gypsum sludge I and the gypsum sludge II to obtain recovered gypsum. The device and method for improving the gypsum yield in desulfurization wastewater provided by the application have the characteristics of high gypsum yield, simple process and low treatment cost.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and specifically to an apparatus and method for increasing the gypsum yield in desulfurization wastewater. Background Technology

[0002] Flue gas pollutants generated by coal-fired power plants are generally treated by limestone-gypsum wet desulfurization. The resulting desulfurization wastewater, after being treated by the "three-compartment" process, will produce desulfurization sludge with strong viscosity and fine particles (average particle size <45μm).

[0003] Desulfurization sludge has a low calorific value and is not suitable for incineration. Currently, the main method for treating desulfurization sludge is landfilling, which requires high levels of impermeability in landfills, wastes significant land resources, and accounts for 5-20% of the solid waste treatment and disposal costs of coal-fired power plants. Therefore, reducing the volume of desulfurization sludge has become a key research focus.

[0004] CN110078340A discloses a system and method for recycling sludge from desulfurization wastewater. This system recovers the clarified and concentrated slurry to an absorption tower, allowing the sludge and gypsum to form a mixture before being discharged together. The mixture is then dewatered by a dewatering machine, eliminating the need for chemical treatment and saving on sludge transportation costs. However, due to the significant differences in dewatering characteristics between concentrated desulfurization sludge and gypsum, directly mixing them not only affects the operation of the dewatering equipment but also leads to high gypsum moisture content and low gypsum recovery rate. Furthermore, the concentrated desulfurization sludge is highly viscous; when mixed with gypsum and centrifuged together, it easily leads to unstable centrifuge operation and high maintenance costs.

[0005] CN113582261A discloses an equipment and method for producing fine gypsum from wet desulfurization sludge. The method involves discharging part of the water from the desulfurization wastewater through a treatment chamber to increase the solids content of the wastewater, and conditioning the wastewater in an equalization tank to ensure the formation of better gypsum in a vacuum dewatering machine. This method can realize the resource utilization of desulfurization sludge, but the process is complex and the sludge treatment cost is high. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of high cost and complex process in the treatment of desulfurization sludge in the prior art, and to overcome the defects of low gypsum yield and poor quality caused by adding flocculants when producing gypsum from desulfurization wastewater.

[0007] To achieve the above objectives, a first aspect of the present invention provides an apparatus for increasing the gypsum production in desulfurization wastewater, the apparatus comprising a separation unit, a conditioning unit, and a dewatering unit;

[0008] The separation unit includes a first storage tank 1, a first hydrocyclone 2, a second storage tank 3, a second hydrocyclone 4, and a third storage tank 5 connected in sequence. The bottom of the first hydrocyclone 2 is connected to a first discharge pipe 15, the bottom of the second hydrocyclone 4 is connected to a second discharge pipe 16, and the third storage tank 5 is connected to a first feeding pipe 17.

[0009] The conditioning unit includes a recycled gypsum feeder 7, a vibrator 8, a conditioning reactor 10, and a sedimentation tank 12 connected in sequence. The conditioning reactor 10 is equipped with a dosing controller 9. The recycled gypsum feeder 7 is connected to the first feeding pipe 17, and the sedimentation tank 12 is connected to the third discharge pipe 22.

[0010] The dehydration unit includes a dehydrator 13, which is connected to the first discharge pipe 15 through a first feeding hole and to the third discharge pipe 22 through a second feeding hole. The distance D1 between the geometric center of the first feeding hole and the center of the dehydrator 13 and the distance D2 between the geometric center of the second feeding hole and the center of the dehydrator 13 satisfy: D1>D2.

[0011] A second aspect of the present invention provides a method for increasing the gypsum yield in desulfurization wastewater, the method comprising:

[0012] (1) The desulfurization slurry is separated to obtain desulfurization wastewater and gypsum sludge I; the desulfurization wastewater contains SO4. 2- And the SO4 2- The concentration of the suspended particulate matter is 3500-8500 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 6000-30000 mg / L.

[0013] (2) The conditioner, recovered gypsum, and the desulfurization wastewater are subjected to a conditioning reaction to obtain gypsum sludge II; the conditioner is calcium oxide or calcium hydroxide; the conditioner and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.5-3; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.1-4.

[0014] (3) Dewater the gypsum sludge I and the gypsum sludge II to obtain recycled gypsum;

[0015] The separation process, the conditioning reaction, and the dehydration process are carried out in the apparatus described in the first aspect of the present invention.

[0016] The apparatus and method for increasing gypsum production in desulfurization wastewater provided by this invention are characterized by simple process, low processing cost, and high yield and quality of recovered gypsum. Attached Figure Description

[0017] Figure 1 This is a diagram of the device provided by the present invention for increasing gypsum production in desulfurization wastewater;

[0018] Figure 2 This is a structural diagram of the dosing controller provided by the present invention.

[0019] Explanation of reference numerals in the attached figures

[0020] a. Collection plate b. Collection funnel c. Discharge port Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] In this invention, the recycled gypsum includes recycled gypsum I and recycled gypsum II.

[0023] As previously described, the first aspect of the present invention provides that the apparatus includes a separation unit, a conditioning unit, and a dehydration unit;

[0024] The separation unit includes a first storage tank 1, a first hydrocyclone 2, a second storage tank 3, a second hydrocyclone 4, and a third storage tank 5 connected in sequence. The bottom of the first hydrocyclone 2 is connected to a first discharge pipe 15, the bottom of the second hydrocyclone 4 is connected to a second discharge pipe 16, and the third storage tank 5 is connected to a first feeding pipe 17.

[0025] The conditioning unit includes a recycled gypsum feeder 7, a vibrator 8, a conditioning reactor 10, and a sedimentation tank 12 connected in sequence. The conditioning reactor 10 is equipped with a dosing controller 9. The recycled gypsum feeder 7 is connected to the first feeding pipe 17, and the sedimentation tank 12 is connected to the third discharge pipe 22.

[0026] The dehydration unit includes a dehydrator 13, which is connected to the first discharge pipe 15 through a first feeding hole and to the third discharge pipe 22 through a second feeding hole. The distance D1 between the geometric center of the first feeding hole and the center of the dehydrator 13 and the distance D2 between the geometric center of the second feeding hole and the center of the dehydrator 13 satisfy: D1>D2.

[0027] In this invention, distances D1 and D2 are both the shortest distances between the geometric center of the feeding hole and the center of the dewatering machine 13.

[0028] Preferably, in the conditioning unit, the dosing controller 9 includes a collection plate, a collection funnel, and a discharge port arranged sequentially from top to bottom; the collection plate is inclined toward the end where the collection funnel is located, and the collection plate is fixed on the conditioning reactor 10; the collection funnel is tightly connected to the discharge port.

[0029] More preferably, in the conditioning unit, the recycled gypsum feeding machine 7 is connected to the first feeding pipe 17 through the recycled gypsum discharge pipe 18, the first feeding pipe 17 is connected to the vibrator 8, the vibrator 8 is connected to the conditioning reactor 10 through the second feeding pipe 19, and the conditioning reactor 10 is connected to the sedimentation tank 12 in sequence through the third feeding pipe 20, the conveying pump 11, and the fourth feeding pipe 21.

[0030] In a preferred embodiment, in the device, the dewatering machine 13 is connected to the recycled gypsum feeder 7 via a pneumatic conveyor 6 and a recycled gypsum feed pipe 23.

[0031] Preferably, in the device, the dehydration unit further includes a fourth storage tank 14, and the fourth storage tank 14 is connected to the dehydrator 13.

[0032] More preferably, the fourth storage tank 14 is connected to the second discharge pipe 16.

[0033] As previously stated, a second aspect of the present invention provides a method for increasing gypsum production in desulfurization wastewater, the method comprising:

[0034] (1) The desulfurization slurry is separated to obtain desulfurization wastewater and gypsum sludge I; the desulfurization wastewater contains SO4. 2- And the SO4 2- The concentration of the suspended particulate matter is 3500-8500 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 6000-30000 mg / L.

[0035] (2) The conditioner, recovered gypsum, and the desulfurization wastewater are subjected to a conditioning reaction to obtain gypsum sludge II; the conditioner is calcium oxide or calcium hydroxide; the conditioner and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.5-3; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.1-4.

[0036] (3) Dewater the gypsum sludge I and the gypsum sludge II to obtain recycled gypsum;

[0037] The separation process, the conditioning reaction, and the dehydration process are carried out in the apparatus described in the first aspect of the present invention.

[0038] Preferably, in step (2), the regulator and the SO4 2- The mass ratio is 1:1.5-3.

[0039] In a preferred embodiment, in step (2), the method further includes: performing a second mixing treatment on the recovered gypsum and the desulfurization wastewater before carrying out the conditioning reaction.

[0040] More preferably, the conditions for the second mixing process are: a temperature of 25-55°C, a vibration frequency of 200-350Hz for the oscillator 8, and a time of 3-5 minutes.

[0041] In a preferred embodiment, in step (2), the conditioning reaction is carried out under stirring, and the conditions of the conditioning reaction are at least: temperature of 25-45℃, rotation speed of 200-350rpm, and time of 0.5-1h.

[0042] Preferably, in step (2), the method further includes adding a regulator to make the pH value of the system 8.5-9.5.

[0043] Preferably, in step (1), the method further includes: performing a first mixing treatment on the desulfurization concentrate before the separation treatment.

[0044] In a preferred embodiment, in step (1), the first mixing process is carried out under stirring, and the conditions of the first mixing process are: temperature of 50-60°C, rotation speed of 150-300 rpm, and time of 20-45 min.

[0045] Preferably, in step (1), the separation process includes a first separation process and a second separation process.

[0046] Preferably, the conditions for the first separation process are at least: pressure of 0.09-0.2 MPa and rotation speed of 600-1000 rpm.

[0047] In a preferred embodiment, the conditions for the second separation process are at least: pressure of 0.1-0.2 MPa and rotation speed of 1200-1800 rpm.

[0048] According to a preferred embodiment, in step (3), the method further includes: before performing the dewatering treatment, the gypsum sludge II is first subjected to sedimentation treatment to obtain supernatant and concentrated gypsum sludge, and then the concentrated gypsum sludge is subjected to the dewatering treatment.

[0049] In a preferred embodiment, the precipitation treatment conditions shall at least satisfy: 35-45℃ and 0.5-0.75h.

[0050] More preferably, in step (3), the conditions for the dehydration treatment are at least: the belt speed is 0.1-0.2 m / s and the vacuum degree is 0.05-0.07 MPa.

[0051] The following combination Figure 1 A preferred embodiment of the method for increasing gypsum production in desulfurization wastewater provided by the present invention is described in detail below, including:

[0052] (1) The desulfurization slurry that has undergone the first mixing treatment in the first storage tank 1 is transported to the first hydrocyclone 2 for the first separation treatment to obtain liquid phase A and gypsum sludge I, and the liquid phase A is transported to the second storage tank 3.

[0053] The gypsum sludge I is conveyed to the dewatering machine 13 through the first discharge pipe 15 for dewatering treatment to obtain recycled gypsum I and dewatering liquid A; the dewatering liquid A is conveyed to the fourth storage tank 14;

[0054] The liquid phase A in the second storage tank 3 is transported to the second hydrocyclone 4 for a second separation process to obtain liquid phase B and desulfurization wastewater. The liquid phase B is transported to the fourth storage tank 14 through the second discharge pipe 16, and the desulfurization wastewater is transported to the third storage tank 5.

[0055] (2) The recovered gypsum and the desulfurization wastewater in the third storage tank 5 are transported to the vibrator 8 through the first feeding pipe 17 for the second mixing treatment, and the resulting mixture is transported to the conditioning reactor 10 through the second feeding pipe 19. At the same time, a conditioning agent is added through the dosing controller 9 to carry out the conditioning reaction, and gypsum sludge II is obtained.

[0056] In the dosing controller 9, the regulator is sequentially fed to the conditioning reactor 10 through the collection plate a, the collection funnel b, and the discharge port c;

[0057] The recycled gypsum is sequentially fed to the first feeding pipe 17 via the pneumatic conveyor 6, the recycled gypsum feed pipe 23, the recycled gypsum adder 7, and the recycled gypsum discharge pipe 18.

[0058] The gypsum sludge II is sequentially fed to the sedimentation tank 12 through the third feed pipe 20, the conveying pump 11, and the fourth feed pipe 21 for sedimentation treatment to obtain supernatant and concentrated gypsum sludge; the supernatant is discharged.

[0059] (3) The concentrated gypsum sludge is transported to the dewatering machine 13 through the third discharge pipe 22 for the dewatering treatment to obtain recycled gypsum II and dewatering liquid B; the dewatering liquid B is transported to the fourth storage tank 14.

[0060] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials are all commercially available products.

[0061] Example 1

[0062] This example provides a method for increasing gypsum production in desulfurization wastewater, and the method is used in... Figure 1 The method, performed in the illustrated apparatus, includes the following steps:

[0063] (1) The desulfurization slurry (mass flow rate of 125t / h) that has undergone the first mixing treatment in the first storage tank 1 is transported to the first hydrocyclone 2 for the first separation treatment to obtain liquid phase A and gypsum sludge I. The liquid phase A is then transported to the second storage tank 3. The first mixing treatment is carried out under stirring, and the conditions of the first mixing treatment are: temperature of 55℃, rotation speed of 300rpm, and time of 30min. The conditions of the first separation treatment are: pressure of 0.18MPa and rotation speed of 850rpm.

[0064] The gypsum sludge I (mass flow rate of 56.25 t / h) is conveyed to the dewatering machine 13 through the first discharge pipe 15 for dewatering treatment to obtain recycled gypsum I and dewatering liquid A; the dewatering liquid A is conveyed to the fourth storage tank 14;

[0065] The conditions for the dehydration treatment are: belt speed of 0.2 m / s and vacuum degree of 0.06 MPa;

[0066] The liquid phase A (mass flow rate of 68.75 t / h) in the second storage tank 3 is transported to the second hydrocyclone 4 for the second separation process to obtain liquid phase B and desulfurization wastewater. The liquid phase B is transported to the fourth storage tank 14 through the second discharge pipe 16, and the desulfurization wastewater is transported to the third storage tank 5.

[0067] The desulfurization wastewater contains SO4 2- And the SO4 2- The concentration of the pollutant is 8260 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 15000 mg / L; the conditions for the second separation treatment are: pressure of 0.1 MPa and rotation speed of 1500 rpm.

[0068] (2) The desulfurization wastewater (mass flow rate of 35 t / h) in the third storage tank 5 and the recovered gypsum are transported to the vibrator 8 through the first feed pipe 17 for a second mixing treatment, and the resulting mixture is transported to the conditioning reactor 10 through the second feed pipe 19. At the same time, 2890 mg / L of calcium oxide is added through the dosing controller 9 (to make the pH value of the system 9.2) to carry out the conditioning reaction and obtain gypsum sludge II; the calcium oxide and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:2.9; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:1.

[0069] The conditions for the second mixing treatment are: temperature 25°C, vibration frequency of the oscillator 8 350Hz, and time 5min; the conditioning reaction is carried out under stirring, and the conditions for the conditioning reaction are: temperature 35°C, rotation speed 300rpm, and time 1h.

[0070] In the dosing controller 9, the calcium oxide is sequentially fed to the conditioning reactor 10 through the collecting plate a, the collecting funnel b, and the discharge port c;

[0071] The recycled gypsum is sequentially fed to the first feeding pipe 17 via the pneumatic conveyor 6, the recycled gypsum feed pipe 23, the recycled gypsum adder 7, and the recycled gypsum discharge pipe 18.

[0072] The gypsum sludge II is sequentially fed to the sedimentation tank 12 through the third feed pipe 20, the conveying pump 11, and the fourth feed pipe 21 for sedimentation treatment to obtain supernatant and concentrated gypsum sludge; the supernatant is discharged externally; the sedimentation treatment conditions are: 45℃, time is 0.5h.

[0073] (3) The concentrated gypsum sludge (mass flow rate of 15.2t / h) is transported to the dewatering machine 13 through the third discharge pipe 22 for the dewatering treatment to obtain recycled gypsum II and dewatering liquid B; the dewatering liquid B is transported to the fourth storage tank 14.

[0074] Example 2

[0075] This example provides a method for increasing gypsum production in desulfurization wastewater, and this method is used in... Figure 1 The method, performed in the illustrated apparatus, includes the following steps:

[0076] (1) The desulfurization slurry (mass flow rate of 60t / h) that has undergone the first mixing treatment in the first storage tank 1 is transported to the first hydrocyclone 2 for the first separation treatment to obtain liquid phase A and gypsum sludge I. The liquid phase A is then transported to the second storage tank 3. The first mixing treatment is carried out under stirring, and the conditions of the first mixing treatment are: temperature of 52℃, rotation speed of 150rpm, and time of 45min. The conditions of the first separation treatment are: pressure of 0.09MPa and rotation speed of 1000rpm.

[0077] The gypsum sludge I (mass flow rate of 27t / h) is conveyed to the dewatering machine 13 through the first discharge pipe 15 for dewatering treatment to obtain recycled gypsum I and dewatering liquid A; the dewatering liquid A is conveyed to the fourth storage tank 14;

[0078] The conditions for the dehydration treatment are: belt speed of 0.1 m / s and vacuum degree of 0.05 MPa;

[0079] The liquid phase A (mass flow rate of 33t / h) in the second storage tank 3 is transported to the second hydrocyclone 4 for the second separation process to obtain liquid phase B and desulfurization wastewater. The liquid phase B is transported to the fourth storage tank 14 through the second discharge pipe 16, and the desulfurization wastewater is transported to the third storage tank 5.

[0080] The desulfurization wastewater contains SO4 2- And the SO4 2- The concentration of the pollutant is 5000 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 6000 mg / L; the conditions for the second separation treatment are: pressure of 0.15 MPa and rotation speed of 1800 rpm.

[0081] (2) The desulfurization wastewater (mass flow rate of 33 t / h) in the third storage tank 5 and the recovered gypsum are transported to the vibrator 8 through the first feed pipe 17 for a second mixing treatment, and the resulting mixture is transported to the conditioning reactor 10 through the second feed pipe 19. At the same time, 2916 mg / L of calcium hydroxide is added through the dosing controller 9 (to make the pH value of the system 8.9) to carry out the conditioning reaction and obtain gypsum sludge II; the calcium hydroxide and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:1.7; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:3.

[0082] The conditions for the second mixing treatment are: temperature 45℃, vibration frequency of the oscillator 8 200Hz, and time 3min; the conditioning reaction is carried out under stirring, and the conditions for the conditioning reaction are: temperature 25℃, rotation speed 200rpm, and time 0.5h.

[0083] In the dosing controller 9, the calcium hydroxide is sequentially fed to the conditioning reactor 10 through the collecting plate a, the collecting funnel b, and the discharge port c;

[0084] The recycled gypsum is sequentially fed to the first feeding pipe 17 via the pneumatic conveyor 6, the recycled gypsum feed pipe 23, the recycled gypsum adder 7, and the recycled gypsum discharge pipe 18.

[0085] The gypsum sludge II is sequentially fed to the sedimentation tank 12 through the third feed pipe 20, the conveying pump 11, and the fourth feed pipe 21 for sedimentation treatment to obtain supernatant and concentrated gypsum sludge; the supernatant is discharged externally; the sedimentation treatment conditions are: 35℃, time is 0.75h.

[0086] (3) The concentrated gypsum sludge (mass flow rate of 6.9t / h) is transported to the dewatering machine 13 through the third discharge pipe 22 for the dewatering treatment to obtain recycled gypsum II and dewatering liquid B; the dewatering liquid B is transported to the fourth storage tank 14.

[0087] Example 3

[0088] This example provides a method for increasing gypsum production in desulfurization wastewater, and this method is used in... Figure 1 The method, performed in the illustrated apparatus, includes the following steps:

[0089] (1) The desulfurization slurry (mass flow rate of 80t / h) that has undergone the first mixing treatment in the first storage tank 1 is transported to the first hydrocyclone 2 for the first separation treatment to obtain liquid phase A and gypsum sludge I. The liquid phase A is then transported to the second storage tank 3. The first mixing treatment is carried out under stirring, and the conditions of the first mixing treatment are: temperature of 60℃, rotation speed of 300rpm, and time of 20min. The conditions of the first separation treatment are: pressure of 0.2MPa and rotation speed of 600rpm.

[0090] The gypsum sludge I (mass flow rate of 36t / h) is conveyed to the dewatering machine 13 through the first discharge pipe 15 for dewatering treatment to obtain recycled gypsum I and dewatering liquid A; the dewatering liquid A is conveyed to the fourth storage tank 14;

[0091] The conditions for the dehydration treatment are: belt speed of 0.13 m / s and vacuum degree of 0.07 MPa;

[0092] The liquid phase A (mass flow rate of 44t / h) in the second storage tank 3 is transported to the second hydrocyclone 4 for the second separation process to obtain liquid phase B and desulfurization wastewater. The liquid phase B is transported to the fourth storage tank 14 through the second discharge pipe 16, and the desulfurization wastewater is transported to the third storage tank 5.

[0093] The desulfurization wastewater contains SO4 2- And the SO4 2- The concentration of the pollutant is 3500 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 30000 mg / L; the conditions for the second separation treatment are: pressure of 0.1 MPa and rotation speed of 1200 rpm.

[0094] (2) The desulfurization wastewater (mass flow rate of 44 t / h) in the third storage tank 5 and the recovered gypsum are transported to the vibrator 8 through the first feed pipe 17 for a second mixing treatment, and the resulting mixture is transported to the conditioning reactor 10 through the second feed pipe 19. At the same time, 2200 mg / L of calcium oxide is added through the dosing controller 9 (to make the pH value of the system 8.7) to carry out the conditioning reaction and obtain gypsum sludge II; the calcium oxide and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:1.6; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.2.

[0095] The conditions for the second mixing treatment are: 55°C, the vibration frequency of the oscillator 8 is 300Hz, and the time is 5min; the conditioning reaction is carried out under stirring, and the conditions for the conditioning reaction are: 45°C, the rotation speed is 350rpm, and the time is 0.75h.

[0096] In the dosing controller 9, the calcium oxide is sequentially fed to the conditioning reactor 10 through the collecting plate a, the collecting funnel b, and the discharge port c;

[0097] The recycled gypsum is sequentially fed to the first feeding pipe 17 via the pneumatic conveyor 6, the recycled gypsum feed pipe 23, the recycled gypsum adder 7, and the recycled gypsum discharge pipe 18.

[0098] The gypsum sludge II is sequentially fed to the sedimentation tank 12 through the third feed pipe 20, the conveying pump 11, and the fourth feed pipe 21 for sedimentation treatment to obtain supernatant and concentrated gypsum sludge; the supernatant is discharged externally; the sedimentation treatment conditions are: 45℃, time is 0.5h.

[0099] (3) The concentrated gypsum sludge (mass flow rate of 9.73 t / h) is transported to the dewatering machine 13 through the third discharge pipe 22 for the dewatering treatment to obtain recycled gypsum II and dewatering liquid B; the dewatering liquid B is transported to the fourth storage tank 14.

[0100] Comparative Example 1

[0101] The procedure is carried out according to the method of Example 1, except that in step (2), recycled gypsum is not added, and the remaining steps and parameters are the same as in Example 1.

[0102] Comparative Example 2

[0103] The method is carried out according to Example 1, except that in step (2), the calcium oxide and the SO4 are... 2- The mass ratio is 1:5, and the remaining steps and parameters are the same as in Example 1.

[0104] The yield and moisture content of the recycled gypsum obtained from the above examples and comparative examples were calculated and analyzed according to GB / T 37785-2019. The results are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] In Table 1, the moisture content is obtained based on the total weight of the recycled gypsum.

[0109] As can be seen from the results in Table 1, the recovered gypsum prepared from desulfurization wastewater using the apparatus and method of the present invention has a higher yield and the recovered gypsum has significantly better quality.

[0110] A comparison of Example 1 and Comparative Example 1 shows that using the prepared recycled gypsum to produce gypsum from desulfurization wastewater, combined with other technical features of the present invention, is beneficial to improving the yield and quality of recycled gypsum.

[0111] A comparison of Example 1 and Comparative Example 2 shows that the calcium oxide and SO4 of the present invention are effective. 2- The dosage-to-mass ratio, combined with other technical features of this invention, is beneficial for increasing the yield of recycled gypsum.

[0112] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An apparatus for increasing gypsum production in desulfurization wastewater, characterized in that, The device includes a separation unit, a conditioning unit, and a dehydration unit; The separation unit includes a first storage tank (1), a first hydrocyclone (2), a second storage tank (3), a second hydrocyclone (4), and a third storage tank (5) connected in sequence. The bottom of the first hydrocyclone (2) is connected to a first discharge pipe (15), the bottom of the second hydrocyclone (4) is connected to a second discharge pipe (16), and the third storage tank (5) is connected to a first feeding pipe (17). The conditioning unit includes a gypsum recycling machine (7), a vibrator (8), a conditioning reactor (10), and a sedimentation tank (12) connected in sequence. The conditioning reactor (10) is equipped with a dosing controller (9). The gypsum recycling machine (7) is connected to the first feeding pipe (17), and the sedimentation tank (12) is connected to the third discharge pipe (22). The dehydration unit includes a dehydrator (13), which is connected to the first discharge pipe (15) through a first feeding hole and to the third discharge pipe (22) through a second feeding hole; the distance D1 between the geometric center of the first feeding hole and the center of the dehydrator (13) and the distance D2 between the geometric center of the second feeding hole and the center of the dehydrator (13) satisfy: D1>D2; The dosing controller (9) includes a collection plate, a collection funnel, and a discharge port arranged sequentially from top to bottom; the collection plate is inclined toward the end where the collection funnel is located, and the collection plate is fixed on the conditioning reactor (10); the collection funnel is tightly connected to the discharge port; The dewatering machine (13) is connected to the recycled gypsum feeder (7) in sequence via a pneumatic conveyor (6) and a recycled gypsum feed pipe (23).

2. The apparatus according to claim 1, wherein, In the conditioning unit, the recycled gypsum feeder (7) is connected to the first feed pipe (17) through the recycled gypsum discharge pipe (18), the first feed pipe (17) is connected to the vibrator (8), the vibrator (8) is connected to the conditioning reactor (10) through the second feed pipe (19), and the conditioning reactor (10) is connected to the sedimentation tank (12) in sequence through the third feed pipe (20), the transfer pump (11), and the fourth feed pipe (21).

3. A method for increasing gypsum production in desulfurization wastewater, characterized in that, The method includes: (1) The desulfurization slurry is separated to obtain desulfurization wastewater and gypsum sludge I; the desulfurization wastewater contains SO4. 2- And the SO4 2- The concentration of the suspended particulate matter is 3500-8500 mg / L; the desulfurization wastewater contains suspended particulate matter, and the concentration of the suspended particulate matter is 6000-30000 mg / L. (2) The conditioner, recovered gypsum, and the desulfurization wastewater are subjected to a conditioning reaction to obtain gypsum sludge II; the conditioner is calcium oxide or calcium hydroxide; the conditioner and the SO4 2- The mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.5-3; the mass ratio of the suspended particulate matter to the recycled gypsum is 1:0.1-4. (3) Dewater the gypsum sludge I and the gypsum sludge II to obtain recycled gypsum; The separation process, the conditioning reaction, and the dehydration process are carried out in the apparatus described in any one of claims 1-2.

4. The method according to claim 3, wherein, In step (2), the regulator, the SO4 2- The mass ratio is 1:1.5-3.

5. The method according to claim 4, wherein, In step (2), the conditioning reaction is carried out under stirring, and the conditions of the conditioning reaction are at least: temperature of 25-45℃, rotation speed of 200-350rpm, and time of 0.5-1h.

6. The method according to claim 5, wherein, In step (2), the method further includes adding a regulator to make the pH value of the system 8.5-9.

5.

7. The method according to claim 6, wherein, In step (1), the separation process includes a first separation process and a second separation process; and / or, The conditions for the first separation process must at least satisfy: pressure of 0.09-0.2 MPa, rotation speed of 600-1000 rpm; and / or, The conditions for the second separation process must at least meet the following requirements: pressure of 0.1-0.2 MPa and rotation speed of 1200-1800 rpm.

8. The method according to claim 7, wherein, In step (3), the conditions for the dehydration treatment must at least meet the following requirements: belt speed of 0.1-0.2 m / s and vacuum degree of 0.05-0.07 MPa.

Images