Stacked vertical type wastewater multi-effect evaporation and concentration device

Abstract

The utility model discloses a stacked vertical type wastewater multi-effect evaporation and concentration device which comprises a main tower body of a concentration tower and a wastewater circulating pipeline which is arranged on the outer side of the main tower body of the concentration tower, one end of the wastewater circulating pipeline is communicated with a liquid holding section, and the other end of the wastewater circulating pipeline is communicated with the tower top of the main tower body of the concentration tower; the plurality of water distribution plates are arranged in the concentrating tower main body; the plurality of groups of demisting devices are mounted on the outer side of the main tower body of the concentration tower, and openings of the demisting devices are respectively positioned below each water distribution plate; the wastewater circulating pump and the heat exchangers are mounted on the wastewater circulating pipeline; and the condensing device is respectively connected with the plurality of heat exchangers through pipelines. The system has the effects of energy consumption reduction, simple system, small occupied area, no need of pretreatment of desulfurization waste water, no scaling of the waste water and high concentration ratio of the waste water.

Description

TECHNICAL FIELD

[0001] The utility model relates to a wastewater treatment equipment, concretely relates to a desulfurization wastewater concentration treatment equipment, belongs to the field of environmental protection. BACKGROUND

[0002] The limestone-gypsum wet desulfurization process is the most widely used and the most mature desulfurization technology in the world, and accounts for more than 90% of the total amount of desulfurization technology of coal-fired power plants in China, and becomes the primary choice of the desulfurization process of the coal-fired power plant at present. The limestone-gypsum wet desulfurization adopts lime milk to absorb SO2 in the flue gas, and generates gypsum in the absorption process. In order to ensure the characteristics of the slurry and the quality of the gypsum, the Cl- concentration is generally controlled, and a certain amount of desulfurization wastewater is discharged regularly and fresh absorption liquid is supplemented. The desulfurization wastewater of the coal-fired power plant has high suspended solids concentration, strong corrosion, easy scaling and high heavy metal content, and has great difficulty in treatment, and has become a key factor restricting the zero discharge of the whole plant wastewater of the thermal power plant.

[0003] At present, the desulfurization wastewater treatment mainly includes three stages of pretreatment, concentration reduction and end zero discharge treatment, wherein the concentration reduction stage mainly has membrane concentration and thermal concentration. The membrane concentration can recover crystalline salt and wastewater, but has the defects of complex system, high investment and operation cost. The thermal concentration mainly includes low-temperature flue gas concentration evaporation process and multi-effect evaporation concentration process. The low-temperature flue gas concentration evaporation process has problems of large inlet and outlet flues, large occupied area, difficult arrangement, low pH value of the concentrated liquid, etc. The multi-effect evaporation concentration process has problems of complex system, large occupied area and high investment cost. CONTENT OF THE UTILITY MODEL

[0004] In view of the problems mentioned in the background art, the utility model aims at providing a desulfurization wastewater concentration device with low energy consumption, simple system, small occupied area, no pretreatment of desulfurization wastewater, no scaling of wastewater, high concentration ratio of wastewater and no chemical treatment of the wastewater concentrated liquid, so as to solve the problems mentioned in the above background art.

[0005] The above technical purpose of the utility model is realized by the following technical scheme:

[0006] A vertical type wastewater multi-effect evaporation concentration device, comprising a concentration tower main body, a transition section below the concentration tower main body, a liquid holding section below the transition section, a wastewater concentrated liquid outlet pipeline installed at the bottom of the liquid holding section, and a wastewater inlet pipeline installed on the side wall of the liquid holding section, further comprising:

[0007] A wastewater circulation pipeline installed outside the concentration tower main body and communicated with the liquid holding section at one end and the top of the concentration tower main body at the other end;

[0008] At least one water distribution plate installed in the concentration tower main body;

[0009] A plurality of demisting devices are installed outside the main tower body of the concentration tower and have openings respectively below each water distribution plate.

[0010] A plurality of heat exchangers and a wastewater circulating pump installed on a wastewater circulating pipeline.

[0011] A wastewater disturbance pipe having an inlet communicated with the outlet of the wastewater circulating pump and an outlet communicated with the liquid holding section.

[0012] A condensing device connected with the plurality of heat exchangers respectively through pipelines.

[0013] Further, the condensing device comprises a condensing tank connected with the plurality of heat exchangers respectively through pipelines.

[0014] A gas-liquid separator connected with the top of the condensing tank through a pipeline.

[0015] A vacuum pump connected with the gas-liquid separator through a pipeline.

[0016] Further, the demisting device comprises a vertical pipeline, a demisting body installed in the vertical pipeline, and an inclined pipeline connected with the vertical pipeline at one end and with the main tower body of the concentration tower at the other end; the inclined pipeline is inclined toward the main tower body of the concentration tower, the included angle a between the inclined pipeline and the horizontal direction is ≥10°, the steam flow rate is ≤30 m / s, and the height of the lower edge of the inclined pipeline from the highest liquid level of the wastewater is ≥0.5 m.

[0017] Further, the water distribution plate is a flat plate with one or more water passing holes uniformly distributed in the middle, and the minimum aperture of the water passing hole is ≥30 mm.

[0018] Further, the heat exchanger comprises at least one zeroth heat exchanger and one supplementary heat exchanger, the initial heat source of the zeroth heat exchanger is a driving heat source, the supplementary heat source of the supplementary heat exchanger is flash steam at the outlet of the demisting device, and the cold side working medium of the heat exchanger is desulfurization wastewater or cooling water.

[0019] Further, the number of water distribution plates is at least two, and the number of demisting devices is the same as the number of water distribution plates.

[0020] Further, the heat exchanger is a tube-in-shell heat exchanger or a wide channel plate heat exchanger, and the material is selected from 2205 stainless steel, 2507 stainless steel, or titanium.

[0021] Further, the liquid holding section is filled with desulfurization wastewater; the upper part of the liquid holding section is cylindrical, and the ratio of the diameter of the upper part of the liquid holding section to the diameter of the main tower body of the concentration tower is 1:1 to 2:1; the lower part of the liquid holding section is conical, and the taper angle of the lower part of the liquid holding section is ≤90°.

[0022] Further, the end of the wastewater disturbance pipe extends into the liquid holding section and the cone section, and the included angle between the wastewater disturbance pipe and the liquid holding section is greater than or equal to 45 degrees.

[0023] Further, the driving heat source is steam, hot water or flue gas, and the temperature of the driving heat source is 60-150 DEG C.

[0024] Further, the medium transported by the wastewater inlet pipeline is desulfurization wastewater or municipal sewage, high-salinity wastewater or other wastewater without pre-treatment, filtration or chemical treatment.

[0025] The working principle of the utility model is as follows:

[0026] The desulfurization wastewater without pre-treatment enters the liquid holding section through the wastewater inlet pipeline, is pumped into the heat exchanger in sequence by the wastewater circulating pump, is heated, enters the concentration tower for flash evaporation, the pressure is reduced, the desulfurization wastewater is vaporized and flashed, the steam is heated after defogging and enters the heat exchanger to heat the circulating desulfurization wastewater, the desulfurization wastewater with reduced temperature is continuously subjected to multi-stage flash evaporation, the steam with reduced temperature enters the corresponding heat exchanger to heat the desulfurization wastewater, the desulfurization wastewater after flash evaporation is reduced in temperature and moisture, and is concentrated.

[0027] In summary, the utility model mainly has the following beneficial effects:

[0028] (1) The utility model has low energy consumption, simple system, small land occupation, no need for pre-treatment of desulfurization wastewater, no scaling of wastewater, high concentration ratio of wastewater, and no need for chemical treatment of the concentrated wastewater.

[0029] (2) The desulfurization wastewater contains a large amount of gypsum crystals, and the scaling substances have the same structure as the crystals.

[0030] (3) In the utility model, the heating and concentration of waste water are the operation processes which are separated from each other; the heating of waste water is completed in a special heat exchanger, and the evaporation and concentration process of waste water is carried out in a concentration tower. In the concentration tower, waste water evaporates on the gas-water interface, and compared with the mode that water evaporates on the metal surface of a heat exchanger in a traditional evaporator, the scaling tendency is obviously reduced. The separated processing mode and the unique evaporation environment provide a more favorable condition for reducing the scaling problem in the waste water processing process, and help to improve the operation stability and efficiency of the whole waste water processing system.

[0031] (4) In the utility model, the desulfurization waste water from the waste water disturbance pipe makes the waste water in the liquid holding section carry out the circumferential motion, and the salt sand in the desulfurization waste water raw water washes and rubs the surface of the liquid holding section, so that the deposition and scaling phenomenon of the desulfurization waste water on the inner wall of the liquid holding section is avoided; the lower end of the liquid holding section is conical, and this shape design can timely discharge the waste water with higher concentration, and can also reduce the adhesion of the crystalline salt to the inner wall. The inner wall scaling problem which may appear in the desulfurization waste water processing process is effectively solved, the stable operation of the equipment and the reliability of the processing effect are guaranteed, and strong support is provided for the smooth progress of the whole waste water processing process.

[0032] (5) In the utility model, the temperature of the desulfurization waste water in the heat exchanger is at a relatively low level, and under this low temperature state, the scaling tendency of waste water is relatively small; the equipment operation obstacles and processing efficiency reduction caused by the scaling problem can be reduced to a certain extent, and the stable operation of the whole desulfurization waste water processing system and the reliability of the processing effect are guaranteed.

[0033] (6) In the utility model, the pH value of the desulfurization waste water concentrate liquid slightly decreases, but basically maintains the unchanged state, and does not need to be treated by additional dosing.

[0034] (7) The utility model effectively reduces the scaling in the evaporation and concentration process of the desulfurization waste water, and at the same time, the waste water concentration ratio is greatly improved, and the concentration ratio is 5-10 times.

[0035] (8) The driving heat source used in the waste water evaporation and concentration of the utility model is from hot water, and the energy density is large, which makes the corresponding pipeline size can be designed smaller, and the arrangement is more flexible. In comparison, the heat source of the traditional low-temperature flue gas concentration evaporation process is from low-temperature flue gas, and the energy density is small, so the required flue size is large, which leads to that the equipment is limited in arrangement. The difference in heat source and energy density directly affects the size of the pipeline and equipment and the flexibility of arrangement.

[0036] (9) The traditional three-effect evaporation needs to set three evaporation towers, while the utility model only needs one concentration tower, which greatly reduces the land occupation. At the same time, since the number of power machines involved in the technology is less, the power consumption per ton of water is significantly lower than that of three-effect evaporation. This technical advantage not only makes the space utilization more efficient, but also shows good economic efficiency in energy consumption, providing a more optimized solution for wastewater treatment, which helps to reduce the operating cost and land resource occupation of enterprises, and improves the overall economic benefit and environmental benefit.

[0037] (10) The utility model has wide applicability, which can not only be effectively applied to the concentration treatment of desulfurization wastewater, but also be extended to the treatment of municipal sewage and high-salinity wastewater and other types of sewage. It helps to promote the overall development and application of sewage treatment technology, improve the recycling efficiency of water resources, reduce environmental pollution, and has important practical value and social significance. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a structural schematic view of the utility model embodiment one;

[0039] Figure 2 is a sectional view of the utility model; Figure 1 is an enlarged view of part A;

[0040] Figure 3 is a top view of the water distribution plate in the utility model embodiment one;

[0041] Figure 4 is a sectional view of the utility model; Figure 3

[0042] Figure 5 is a structural schematic view of the utility model embodiment two;

[0043] Figure 6 is a top view of the water distribution plate in the utility model embodiment three;

[0044] Figure 7 is a sectional view of the utility model; Figure 6

[0045] REFERENCE SIGNS:

[0046] ​​The concentrated tower main tower body 1, the transition section 2, the liquid holding section 3, the wastewater concentrated liquid outlet pipeline 4, the wastewater inlet pipeline 5, the wastewater circulating pipeline 6, the first water distribution plate 7, the second water distribution plate 8, the third water distribution plate 9, the first demisting device 10, the second demisting device 11, the third demisting device 12, the wastewater circulating pump 13, the second heat exchanger 14, the first heat exchanger 15, the zeroth heat exchanger 16, the wastewater turbulence pipe 17, the condensing tank 18, the gas-liquid separator 19, the vacuum pump 20, the vertical pipeline 21, the demister body 22, the inclined pipeline 23, the water passage hole 24, the driving heat source 25, the third heat exchanger 26, the cooling water supply pipeline 27, the cooling water return pipeline 28, the flat plate 29, the fourth water distribution plate 30, the fourth demisting device 31, and the fourth heat exchanger 32. DETAILED DESCRIPTION

[0047] Embodiment one

[0048] Reference Figures 1 to 4 The vertical wastewater multi-effect evaporation concentration device includes a concentrated tower main tower body 1, a transition section 2 below the concentrated tower main tower body, a liquid holding section 3 below the transition section, a wastewater concentrated liquid outlet pipeline 4 installed at the bottom of the liquid holding section, and a wastewater inlet pipeline 5 installed on the sidewall of the liquid holding section.

[0049] A wastewater circulating pipeline 6 installed outside the concentrated tower main tower body and communicating with the liquid holding section at one end and with the top of the concentrated tower main tower body at the other end;

[0050] First, second, and third water distribution plates 7, 8, and 9 installed at intervals inside the concentrated tower main tower body;

[0051] First, second, and third demisting devices 10, 11, and 12 installed outside the concentrated tower main tower body and having openings at the lower parts of the first, second, and third water distribution plates, respectively;

[0052] A wastewater circulating pump 13, a second heat exchanger 14, a first heat exchanger 15, and a zeroth heat exchanger 16 installed in the wastewater circulating pipeline in the direction from the liquid holding section to the top of the tower;

[0053] A third heat exchanger 26 connected to the third demisting device, a cooling water supply pipeline 27, and a cooling water return pipeline 28 through pipelines;

[0054] A wastewater turbulence pipe 17 communicating with the outlet of the wastewater circulating pump and with the liquid holding section;

[0055] A condensing tank 18 connected to the second heat exchanger and the third heat exchanger through pipelines;

[0056] A gas-liquid separator 19 connected to the top of the condensing tank through a pipeline;

[0057] A vacuum pump 20 is connected to the gas-liquid separator through a pipeline.

[0058] The first mist eliminator, the second mist eliminator and the third mist eliminator are all composed of a vertical pipeline 21, a mist eliminator body 22 installed in the vertical pipeline, and an inclined pipeline 23 connected to one end of the vertical pipeline and the main tower body of the concentration tower; the inclined pipeline is inclined to the main tower body of the concentration tower, the included angle a between the inclined pipeline and the horizontal direction is greater than or equal to 10 degrees, the steam flow rate is less than or equal to 30 m / s, and the distance between the lower end of the inclined pipeline and the highest liquid level of the wastewater is greater than or equal to 0.5 m.

[0059] The first water distribution plate, the second water distribution plate and the third water distribution plate are all flat plates 29 with a water distribution hole 24 in the middle, the minimum diameter of the water distribution hole is greater than or equal to 30 mm, and the distance between two adjacent water distribution plates is greater than or equal to 1 m.

[0060] The hot side working medium of the zeroth heat exchanger is a driving heat source 25, the cold side working medium of the zeroth heat exchanger is the desulfurization wastewater at the outlet of the first heat exchanger; the hot side working medium of the first heat exchanger is the flash steam at the outlet of the first mist eliminator, the cold side working medium of the first heat exchanger is the desulfurization wastewater at the outlet of the second heat exchanger; the hot side working medium of the second heat exchanger is the flash steam at the outlet of the second mist eliminator, the cold side working medium of the second heat exchanger is the desulfurization wastewater at the outlet of the wastewater circulating pump; the hot side working medium of the third heat exchanger is the flash steam at the outlet of the third mist eliminator, and the cold side working medium of the third heat exchanger is cooling water 26.

[0061] The zeroth heat exchanger, the first heat exchanger and the second heat exchanger are tube-shell heat exchangers or wide-channel plate heat exchangers, and the material is selected from 2205 stainless steel, 2507 stainless steel or titanium.

[0062] The liquid holding section is filled with desulfurization wastewater; the upper part of the liquid holding section is cylindrical, and the ratio of the diameter of the upper part of the liquid holding section to the diameter of the main tower body of the concentration tower is 1:1 to 2:1; the lower part of the liquid holding section is conical, and the conical angle of the lower part of the liquid holding section is less than or equal to 90 degrees.

[0063] The end of the wastewater turbulence pipe extends into the conical section of the liquid holding section, and the included angle between the wastewater turbulence pipe and the liquid holding section is greater than or equal to 45 degrees.

[0064] The driving heat source is hot water, and the temperature of the driving heat source is 60-150 DEG C.

[0065] The wastewater inlet pipeline transports desulfurization wastewater without pre-treatment such as precipitation, filtration and chemical addition.

[0066] The working principle of the utility model is as follows:

[0067] The untreated desulfurization wastewater enters the liquid holding section through the wastewater inlet pipeline, and is pumped into the second heat exchanger, the first heat exchanger and the zeroth heat exchanger in turn by the wastewater circulating pump to be heated, and then enters the first flash evaporation chamber of the concentration tower, so that the pressure is reduced and the desulfurization wastewater is vaporized and flashed to generate steam. The steam enters the first heat exchanger after demisting to heat the circulating desulfurization wastewater, and the desulfurization wastewater with reduced temperature continues to enter the second flash evaporation chamber and the third flash evaporation chamber, and the steam with gradually reduced temperature is flashed into the second heat exchanger and the third heat exchanger to heat the desulfurization wastewater and condense into condensed water, respectively. The desulfurization wastewater after flashing has reduced temperature and water content, and is concentrated. The condensed water of the zeroth heat exchanger, the first heat exchanger, the second heat exchanger and the third heat exchanger is stored in the condensate tank, and the non-condensed gas is pumped out by the vacuum pump to ensure the vacuum degree of the flash evaporation tower.

[0068] Example two

[0069] Reference Figure 5 In the vertical wastewater multi-effect evaporation concentration device in the embodiment, a concentration tower main tower body 1 is provided, the lower part of the concentration tower main tower body is a transition section 2, the lower part of the transition section is a liquid holding section 3, a wastewater concentration liquid outlet pipeline 4 is installed at the bottom of the liquid holding section, and a wastewater inlet pipeline 5 is installed on the side wall of the liquid holding section. The device further comprises:

[0070] A wastewater circulating pipeline 6 is installed on the outer side of the concentration tower main tower body, one end of the wastewater circulating pipeline is communicated with the liquid holding section, and the other end is communicated with the top of the concentration tower main tower body;

[0071] First, second, third and fourth water distribution plates 7, 8, 9 and 30 are installed in the concentration tower main tower body at intervals;

[0072] First, second, third and fourth demisting devices 10, 11, 12 and 31 are installed on the outer side of the concentration tower main tower body, and the openings of the first, second, third and fourth demisting devices are located at the lower part of the first, second, third and fourth water distribution plates, respectively;

[0073] A wastewater circulating pump 13, a fourth heat exchanger 32, a second heat exchanger 14, a first heat exchanger 15 and a zeroth heat exchanger 16 are installed on the wastewater circulating pipeline in the direction from the liquid holding section to the top of the tower in sequence;

[0074] A third heat exchanger 26 is connected to the third demisting device, a cooling water supply pipeline 27 and a cooling water return pipeline 28 through pipelines;

[0075] A wastewater disturbance pipeline 17 is connected to the outlet of the wastewater circulating pump and the liquid holding section;

[0076] A condensate tank 18 is connected to the second heat exchanger and the third heat exchanger through pipelines;

[0077] A gas-liquid separator 19 is connected to the top of the condensate tank through a pipeline.

[0078] A vacuum pump 20 is connected to the gas-liquid separator through a pipeline.

[0079] The hot side working medium of the zeroth heat exchanger is the driving heat source 25, and the cold side working medium of the zeroth heat exchanger is the desulfurization wastewater at the outlet of the first heat exchanger; the hot side working medium of the first heat exchanger is the flash steam at the outlet of the first mist eliminator, and the cold side working medium of the first heat exchanger is the desulfurization wastewater at the outlet of the second heat exchanger; the hot side working medium of the second heat exchanger is the flash steam at the outlet of the second mist eliminator, and the cold side working medium of the second heat exchanger is the desulfurization wastewater at the outlet of the wastewater circulating pump; the hot side working medium of the fourth heat exchanger is the flash steam at the outlet of the third mist eliminator, and the cold side working medium of the fourth heat exchanger is the desulfurization wastewater at the outlet of the wastewater circulating pump; the hot side working medium of the third heat exchanger is the flash steam at the outlet of the fourth mist eliminator, and the cold side working medium of the third heat exchanger is the cooling water 26.

[0080] Example Three

[0081] Reference Figure 6 and Figure 7 In this embodiment, the first water distribution plate, the second water distribution plate, the third water distribution plate and the fourth water distribution plate are all middle plates with multiple water holes uniformly distributed.

[0082] Example Four

[0083] In this embodiment, the wastewater inlet pipeline transports municipal sewage, high-salinity wastewater and other sewage.

Claims

1. A multi-effect evaporation concentration device for wastewater, comprising a main tower body (1) of a concentration tower, a transition section (2) below the main tower body (1), a liquid holding section (3) below the transition section (2), a wastewater concentrated liquid outlet pipeline (4) installed at the bottom of the liquid holding section (3), and a wastewater inlet pipeline (5) installed on the sidewall of the liquid holding section (3), characterized in that, Also comprising: a waste water circulation pipeline (6) installed outside the main tower body (1) of the concentration tower, with one end communicating with the liquid holding section (3) and the other end communicating with the top of the main tower body (1) of the concentration tower; at least one water distribution plate installed in the main tower body (1) of the concentration tower; a demisting device installed outside the main tower body (1) of the concentration tower, with openings respectively located below each water distribution plate; a waste water circulation pump (13) and multiple heat exchangers installed on the waste water circulation pipeline (6); a condensing device connected to each of the multiple heat exchangers through a pipeline.

2. A vertical type wastewater multi-effect evaporation concentration device according to claim 1, characterized in that, The demisting device comprises a vertical pipeline (21), a demister body (22) installed in the vertical pipeline (21), and an inclined pipeline (23) connected to the vertical pipeline (21) at one end and to the main tower body (1) of the concentration tower at the other end; the inclined pipeline (23) is inclined towards the main tower body (1) of the concentration tower.

3. A vertical type wastewater multi-effect evaporation concentration device according to claim 2, characterized in that, The angle α between the inclined pipeline (23) and the horizontal direction is ≥10°.

4. A vertical type wastewater multi-effect evaporation concentration device according to claim 1, wherein It also comprises a waste water disturbance pipeline (17) with an inlet communicating with the outlet of the waste water circulation pump (13) and an outlet communicating with the liquid holding section (3).

5. A vertical type wastewater multi-effect evaporation concentration device according to claim 1, wherein The heat exchanger comprises at least one zeroth heat exchanger and one supplementary heat exchanger, the initial heat source of the zeroth heat exchanger is the driving heat source (25), the supplementary heat source of the supplementary heat exchanger is the flash steam at the outlet of the demisting device, and the cold side working medium of the heat exchanger is desulfurization waste water or cooling water.

6. A vertical type wastewater multi-effect evaporation concentration device according to claim 1, 2, 3, 4 or 5, characterized in that, The number of water distribution plates is at least two, and the number of demisting devices is the same as the number of water distribution plates.

7. A vertical type wastewater multi-effect evaporation concentration device according to claim 6, wherein The heat exchanger is a shell-and-tube heat exchanger or a wide-channel plate heat exchanger, made of 2205 stainless steel, 2507 stainless steel, or titanium.

8. A vertical type wastewater multi-effect evaporation concentration device according to claim 6, wherein The liquid holding section (3) is filled with desulfurization waste water, the upper part of the liquid holding section (3) is cylindrical, and the lower part of the liquid holding section (3) is conical.

9. A vertical type wastewater multi-effect evaporation concentration device according to claim 4, wherein The end of the waste water disturbance pipeline (17) extends into the conical section of the liquid holding section (3).

10. A vertical type wastewater multi-effect evaporation concentration device according to claim 5, wherein The driving heat source (25) is steam, hot water, or flue gas.

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