Dual-alkali water treatment device

Abstract

The utility model discloses a water treatment device adopting a dual-alkali method. The water treatment device comprises an alkalinity removal reaction tank, a hardness removal reaction tank, a first overhaul standby pipe and a second overhaul standby pipe, a first valve is arranged at a water inlet of the alkalinity removal reaction tank, a third valve is arranged at a water outlet of the alkalinity removal reaction tank, and calcium hydroxide, sodium hydroxide and sodium carbonate inlets are respectively formed in the alkalinity removal reaction tank; a fifth valve is arranged at a water inlet of the hardness-removing reaction tank, a seventh valve is arranged at a water outlet of the hardness-removing reaction tank, and the hardness-removing reaction tank is respectively provided with a sodium carbonate inlet and a sodium hydroxide inlet; one end of a first overhaul standby pipe is connected with the upstream of the water inlet of the first valve, and the other end is connected with a pipeline between the third and fifth valves; one end of the second overhaul standby pipe is connected with the pipeline between the third valve and the fifth valve, and the other end is connected with the downstream of the water outlet of the seventh valve. According to the device, a standby reaction tank is omitted, and a sodium hydroxide dosing point is additionally arranged, so that the investment and the occupied area of the device are reduced, and the safe and stable operation of the reaction tank during maintenance is ensured.

Description

Technical Field

[0001] The utility model belongs to the field of power plant wastewater treatment, and in particular relates to a double alkali method water treatment device. Background Art

[0002] At present, the wastewater from power plants has high hardness (mainly Ca 2+ Mg 2+ ) and high alkalinity (HCO3 - ) problem, which is not conducive to subsequent water treatment. In order to remove the hardness and alkalinity in wastewater, a double alkali treatment process is generally adopted, that is, calcium hydroxide and sodium carbonate are added to remove alkalinity and hardness. The main reaction formula is as follows:

[0003] Ca(OH)2+Ca(HCO3)2→2Ca CO3↓+2H2O

[0004] Na2CO3+Ca 2+ →CaCO3↓+2Na +

[0005] The main hardness ions are Ca 2+ and Mg 2+ , the above only lists Ca 2+ The relevant reaction formula, Mg 2+ The reaction equation is similar to that of ; and for the sake of cost and ease of procurement, the main agent added in the project is Ca(OH)2.

[0006] However, if two reagents are added to a reaction tank at the same time, the following reactions will occur between the reagents:

[0007] Ca(OH)2+Na2CO3→CaCO3↓+2NaOH. Although this reaction has little effect on alkalinity removal, it loses the function of allowing Na2CO3 to remove hardness ions. Therefore, two reaction tanks should be used to separately add Ca(OH)2 and Na2CO3.

[0008] Considering the maintenance of the reaction pool, it is necessary to consider setting up a spare reaction pool, that is, two alkalinity removal reaction pools and two hardness removal reaction pools should be set up respectively, one for normal operation and the other as a spare reaction pool for maintenance. A total of four reaction pools are required, such as Figure 1 As shown in the figure, valves V1-V8 are isolation valves for each reaction tank, and valves V01-V04 are dosing valves for each reaction tank. Since the reaction tanks require a certain hydraulic retention time and occupy a large area, when backup is considered, the system footprint and process investment are significantly increased. Therefore, it is necessary to develop a water treatment device with a simple structure, a small footprint, and low cost. Utility Model Content

[0009] This utility model is based on the inventor's discovery and understanding of the following facts and problems: existing water treatment devices require four reaction tanks when considering maintenance and standby conditions, which inevitably results in large floor space and high investment costs. Therefore, it is necessary to conduct in-depth research and improvement on water treatment devices.

[0010] The present invention aims to address, at least to a certain extent, one of the technical problems in the related art. To this end, embodiments of the present invention provide a dual-alkali water treatment device that combines a conventional hardness removal reaction tank with an alkalinity removal reaction tank, eliminating their respective standby reaction tanks and adding a sodium hydroxide dosing point. This significantly reduces the investment and footprint of the reaction tanks while ensuring safe and stable operation during reaction tank maintenance.

[0011] A dual-alkali water treatment device according to an embodiment of the present invention comprises an alkalinity removal reaction tank, a hardness removal reaction tank, a first maintenance standby pipe and a second maintenance standby pipe;

[0012] A first valve is provided at the water inlet of the alkalinity removal reaction tank, and a third valve is provided at the water outlet. In addition, the alkalinity removal reaction tank is respectively provided with a calcium hydroxide inlet, a sodium hydroxide inlet, and a sodium carbonate inlet, wherein the calcium hydroxide inlet is connected to the first inlet valve, the sodium hydroxide inlet is connected to the third inlet valve, and the sodium carbonate inlet is connected to the fifth inlet valve;

[0013] A fifth valve is provided at the water inlet of the hardness removal reaction tank, and a seventh valve is provided at the water outlet. The water inlet of the fifth valve is connected to the water outlet of the third valve. In addition, a sodium carbonate inlet and a sodium hydroxide inlet are provided in the hardness removal reaction tank, respectively. The sodium carbonate inlet is connected to the second inlet valve, and the sodium hydroxide inlet is connected to the fourth inlet valve.

[0014] One end of the first maintenance standby pipe is connected to the upstream pipeline of the first valve water inlet, and the other end is connected to the pipeline between the third valve and the fifth valve, and the second valve and the fourth valve are provided on the first maintenance standby pipe;

[0015] One end of the second maintenance spare pipe is connected to the pipeline between the third valve and the fifth valve, and the other end is connected to the downstream pipeline of the seventh valve outlet, and the sixth valve and the eighth valve are set on the second maintenance spare pipe.

[0016] The advantages and technical effects brought by the dual-alkali water treatment device of the embodiment of the present invention are as follows: the spare alkalinity removal reaction tank and the spare hardness removal reaction tank in the dual-alkali water treatment device of the prior art are eliminated, a first maintenance spare pipe and a second maintenance spare pipe are added, and a sodium hydroxide inlet is added to the alkalinity removal reaction tank and the hardness removal reaction tank, which simplifies the process, saves the floor space of the device, reduces the investment cost, and at the same time ensures that the entire water treatment system can still operate effectively and continuously when a single reaction tank is under maintenance.

[0017] In some embodiments, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve or the eighth valve is a butterfly valve.

[0018] In some embodiments, the first drug inlet valve, the second drug inlet valve, the third drug inlet valve, the fourth drug inlet valve or the fifth drug inlet valve is a ball valve or a stop valve.

[0019] In some embodiments, the water inlet of the first valve is connected to a high hardness and alkalinity wastewater tank.

[0020] In some embodiments, the water outlet of the seventh valve is connected to a soft water tank.

[0021] In some embodiments, the drug inlet of the first drug inlet valve is connected to the calcium hydroxide storage tank.

[0022] In some embodiments, the drug inlet of the second drug inlet valve and the drug inlet of the fifth drug inlet valve are respectively connected to the sodium carbonate storage tank.

[0023] In some embodiments, the drug inlet of the third drug inlet valve and the drug inlet of the fourth drug inlet valve are respectively connected to the sodium hydroxide storage tank.

[0024] In some embodiments, the second valve and the fourth valve are respectively disposed at two ends of the first maintenance spare pipe.

[0025] In some embodiments, the sixth valve and the eighth valve are respectively provided at both ends of the second maintenance spare pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a double alkali water treatment device of the prior art;

[0027] Figure 2 The utility model relates to a double alkali method water treatment device.

[0028] Figure numerals: 1, alkalinity removal reaction tank; 2, hardness removal reaction tank; 3, first maintenance spare pipe; 4, second maintenance spare pipe; V1, first valve; V2, second valve; V3, third valve; V4, fourth valve; V5, fifth valve; V6, sixth valve; V7, seventh valve; V8, eighth valve; V01, first drug inlet valve; V02, second drug inlet valve; V03, third drug inlet valve; V04, fourth drug inlet valve; V05, fifth drug inlet valve. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0030] like Figure 2 As shown, the dual-alkali water treatment device of the embodiment of the utility model includes an alkalinity removal reaction tank 1, a hardness removal reaction tank 2, a first maintenance spare pipe 3 and a second maintenance spare pipe 4.

[0031] A first valve V1 is provided at the water inlet of the alkalinity removal reaction tank 1, and a third valve V3 is provided at the water outlet. The alkalinity removal reaction tank 1 is provided with a calcium hydroxide inlet, a sodium hydroxide inlet, and a sodium carbonate inlet, respectively. The calcium hydroxide inlet is connected to the first inlet valve V01, the sodium hydroxide inlet is connected to the third inlet valve V03, and the sodium carbonate inlet is connected to the fifth inlet valve V05.

[0032] The hardness removal reaction tank 2 is equipped with a fifth valve V5 at the water inlet and a seventh valve V7 at the water outlet. The water inlet of the fifth valve V5 is connected to the water outlet of the third valve V3. The hardness removal reaction tank 2 is also equipped with a sodium carbonate inlet and a sodium hydroxide inlet. The sodium carbonate inlet is connected to the second inlet valve V02, and the sodium hydroxide inlet is connected to the fourth inlet valve V04.

[0033] One end of the first maintenance standby pipe 3 is connected to the upstream pipeline of the water inlet of the first valve V1, and the other end is connected to the pipeline between the third valve V3 and the fifth valve V5. The second valve V2 and the fourth valve V4 are set on the first maintenance standby pipe 3. Preferably, the second valve V2 and the fourth valve V4 are respectively set at both ends of the first maintenance standby pipe 3.

[0034] One end of the second maintenance standby pipe 4 is connected to the pipeline between the third valve V3 and the fifth valve V5, and the other end is connected to the downstream pipeline of the water outlet of the seventh valve V7. A sixth valve V6 and an eighth valve V8 are provided on the second maintenance standby pipe 4. Preferably, the sixth valve V6 and the eighth valve V8 are respectively provided at both ends of the second maintenance standby pipe 4.

[0035] Preferably, the first valve V1 , the second valve V2 , the third valve V3 , the fourth valve V4 , the fifth valve V5 , the sixth valve V6 , the seventh valve V7 or the eighth valve V8 is a butterfly valve.

[0036] Preferably, the first drug inlet valve V01, the second drug inlet valve V02, the third drug inlet valve V03, the fourth drug inlet valve V04 or the fifth drug inlet valve V05 is a ball valve or a stop valve.

[0037] Preferably, the water inlet of the first valve V1 is connected to a high-hardness and alkalinity wastewater tank; the water outlet of the seventh valve V7 is connected to a soft water tank; the drug inlet of the first drug inlet valve V01 is connected to a calcium hydroxide storage tank; the drug inlets of the second drug inlet valve V02 and the fifth drug inlet valve V05 are each connected to a sodium carbonate storage tank; and the drug inlets of the third drug inlet valve V3 and the fourth drug inlet valve V4 are each connected to a sodium hydroxide storage tank. The wastewater tank, various drug tanks, and soft water tank are not shown in the figure.

[0038] The working process of the double alkali water treatment device of the utility model is as follows:

[0039] During the operation of the following water treatment device, the wastewater removes high hardness ions and Ca 2+ For example, Mg 2+ The reaction formula is similar to that of , so I will not repeat it here.

[0040] (1) The dual alkali water treatment device operates normally

[0041] When the dual alkali water treatment device is operating normally, close the second valve V2, the fourth valve V4, the sixth valve V6 and the eighth valve V8, that is, close the first maintenance standby pipe 3 and the second maintenance standby pipe 4, and at the same time close the third drug inlet valve V03 and the fourth drug inlet valve V04, that is, do not add NaOH to the alkalinity removal reaction tank 1 and the hardness removal reaction tank 2, and all other valves are open. At this time, the high hardness and alkalinity wastewater enters the alkalinity removal reaction tank 1 through the first valve V1 to react, and the reaction formula is: Ca(OH)2+2HCO3 - →2CaCO3↓+2H2O chemical reaction, after removing alkalinity, the wastewater flows out of the alkalinity removal reaction tank 1 through the third valve, and enters the hardness removal reaction tank 2 through the fifth valve V5 for reaction. The reaction formula is Na2CO3+Ca 2+ →CaCO3↓+2Na + , further remove the hardness, and the softened water obtained after treatment enters the soft water tank.

[0042] (2) Maintenance of alkalinity removal reaction tank

[0043] When the alkalinity removal reaction tank 1 needs maintenance, the first valve V1 and the third valve V3 are closed, the second valve V2 and the fourth valve V4 are opened, the first maintenance standby pipe 3 is activated, and the alkalinity removal reaction tank 1 is isolated for maintenance work; at the same time, the first drug inlet valve V01 is closed, the addition of Ca(OH)2 to the alkalinity removal reaction tank 1 is cut off, and the third drug inlet valve V03 is closed; the fifth valve V5 and the seventh valve V7 of the hardness removal reaction tank 2 are opened, the sixth valve V6 and the eighth valve V8 are closed, and the second drug inlet valve V02 and the fourth drug inlet valve V04 are opened.

[0044] At this point, alkalinity removal tank 1 is completely isolated, and the relevant dosing points are closed for maintenance. High-hardness and alkalinity wastewater enters the first maintenance standby pipe 3 through the second valve V2, flows through the fourth valve V4 and the fifth valve V5, and enters the hardness removal tank 2. With the second and fourth drug inlet valves V02 and V04 open, sodium carbonate and sodium hydroxide are added to the hardness removal tank 2. The following reactions occur in the hardness removal tank 2:

[0045] 2NaOH+Ca(HCO3)2→Ca CO3↓+Na2CO3+2H2O

[0046] Na2CO3+Ca 2+ →CaCO3↓+2Na +

[0047] From the above reaction formula, we can know that Ca in wastewater 2+ and HCO3 - were effectively removed.

[0048] (3) Maintenance of hardness reaction tank

[0049] When the hardness removal reaction tank 2 needs maintenance, close the fifth valve V5 and the seventh valve V7, open the sixth valve V6 and the eighth valve V8, activate the second maintenance standby pipe 4, and isolate the hardness removal reaction tank 2 for maintenance work; at the same time, close the second drug inlet valve V02, cut off the addition of Na2CO3 to the hardness removal reaction tank 2, and close the fourth drug inlet valve V04; open the first valve V1 and the third valve V3 of the alkalinity removal reaction tank 1, close the second valve V2 and the fourth valve V4, open the third drug inlet valve V03 and the fifth drug inlet valve V05, close the first drug inlet valve V01, and cut off the addition of the agent Ca(OH)2 to the alkalinity removal reaction tank 1.

[0050] At this point, hardness removal reaction tank 2 is completely isolated, and the relevant dosing points are closed for maintenance. High-hardness and alkalinity wastewater enters de-alkalinity reaction tank 1 through first valve V1. With third and fifth drug inlet valves V03 and V05 open, sodium hydroxide and sodium carbonate are added to de-alkalinity reaction tank 1. The following reactions occur in de-alkalinity reaction tank 1:

[0051] 2NaOH+Ca(HCO3)2→Ca CO3↓+Na2CO3+2H2O

[0052] Na2CO3+Ca 2+ →CaCO3↓+2Na +

[0053] After the reaction is completed, the obtained soft water flows out of the de-alkalinity reaction tank 1 through the third valve V3, enters the second maintenance standby pipe 4 through the sixth valve V6, and is sent to the soft water tank after passing through the eighth valve V8.

[0054] The utility model realizes low-cost operation of high-hardness and high-alkalinity wastewater treatment by adding Ca(OH)2 and Na2CO3 in the alkalinity removal reaction tank and the hardness removal reaction tank by adding a sodium hydroxide inlet and two-way maintenance spare pipes, under normal circumstances, greatly saving the land occupied and engineering investment required for setting up spare reaction tanks in the prior art; at the same time, it ensures that when a certain reaction tank is under maintenance, the other reaction tank can operate normally by adding NaOH and Na2CO3, and because the maintenance time is usually very short, the NaOH added during the maintenance period has a very limited effect on the increase in wastewater treatment cost.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0057] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0059] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0060] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A dual alkali water treatment device, characterized in that: It includes an alkalinity removal reaction tank, a hardness removal reaction tank, a first maintenance spare pipe and a second maintenance spare pipe; A first valve is provided at the water inlet of the alkalinity removal reaction tank, and a third valve is provided at the water outlet. In addition, the alkalinity removal reaction tank is respectively provided with a calcium hydroxide inlet, a sodium hydroxide inlet, and a sodium carbonate inlet, wherein the calcium hydroxide inlet is connected to the first inlet valve, the sodium hydroxide inlet is connected to the third inlet valve, and the sodium carbonate inlet is connected to the fifth inlet valve; A fifth valve is provided at the water inlet of the hardness removal reaction tank, and a seventh valve is provided at the water outlet. The water inlet of the fifth valve is connected to the water outlet of the third valve. In addition, a sodium carbonate inlet and a sodium hydroxide inlet are provided in the hardness removal reaction tank, respectively. The sodium carbonate inlet is connected to the second inlet valve, and the sodium hydroxide inlet is connected to the fourth inlet valve. One end of the first maintenance standby pipe is connected to the upstream pipeline of the first valve water inlet, and the other end is connected to the pipeline between the third valve and the fifth valve, and the second valve and the fourth valve are provided on the first maintenance standby pipe; One end of the second maintenance spare pipe is connected to the pipeline between the third valve and the fifth valve, and the other end is connected to the downstream pipeline of the seventh valve outlet, and the sixth valve and the eighth valve are set on the second maintenance spare pipe.

2. The dual alkali water treatment device according to claim 1, characterized in that: The first valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve or the eighth valve is a butterfly valve.

3. The dual alkali water treatment device according to claim 1, characterized in that: The first medicine inlet valve, the second medicine inlet valve, the third medicine inlet valve, the fourth medicine inlet valve or the fifth medicine inlet valve is a ball valve or a stop valve.

4. The dual alkali water treatment device according to claim 1, characterized in that: The water inlet of the first valve is connected to the high hardness and alkalinity wastewater tank.

5. The dual alkali water treatment device according to claim 1, characterized in that: The water outlet of the seventh valve is connected to the soft water tank.

6. The dual alkali water treatment device according to claim 1, characterized in that: The drug inlet of the first drug inlet valve is connected to the calcium hydroxide storage tank.

7. The dual alkali water treatment device according to claim 1, characterized in that: The drug inlet of the second drug inlet valve and the drug inlet of the fifth drug inlet valve are respectively connected to the sodium carbonate storage tank.

8. The dual alkali water treatment device according to claim 1, characterized in that: The drug inlet of the third drug inlet valve and the drug inlet of the fourth drug inlet valve are respectively connected to the sodium hydroxide storage tank.

9. The dual alkali water treatment device according to claim 1, characterized in that: The second valve and the fourth valve are respectively arranged at two ends of the first maintenance standby pipe.

10. The dual alkali water treatment device according to claim 1, characterized in that: The sixth valve and the eighth valve are respectively arranged at two ends of the second maintenance standby pipe.

Images