Resource utilization system for neutralization method deacidification salt-containing wastewater

Abstract

According to the neutralization method deacidification salt-containing wastewater resource utilization system provided by the utility model, the deacidification wastewater is naturally cooled through the cooling pool, so that the use of electric power resources is reduced; the closed heat exchange coil pipe is communicated with circulating cooling water, the deacidification wastewater enters the cooler and then is atomized and sprayed, and the atomized deacidification wastewater and the high-temperature cooling water in the heat exchange coil pipe are subjected to indirect cooling and heat exchange, so that water vapor in the deacidification wastewater is evaporated, the salt concentration of the deacidification wastewater is increased, and the energy consumption is reduced. The closed heat exchange coil pipe can ensure that the cooling water and the deacidification wastewater are not mixed, so that the cooling water in the technical scheme of the invention can simultaneously use high-temperature liquid needing heat exchange in the system, and not only is the heating evaporation of the deacidification wastewater realized, but also the cooling of the liquid in the heat exchange coil pipe can be realized; and the overall energy consumption of the system is further reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of resource utilization of deacidified wastewater, in particular to a resource utilization system of deacidified salt-containing wastewater by a neutralization method. Background Art

[0002] In the process of exhaust gas purification, alkaline solution is usually used to neutralize the acidic gas in the exhaust gas to purify the acidic gas in the flue gas, but this wet deacidification process will produce a large amount of saline wastewater. The existing technology usually uses membrane filtration, membrane concentration, steam indirect evaporation concentration or flue gas drying to treat wet deacidification saline wastewater. For example, in the technical solution disclosed in the patent with application number CN201910306601.8, the deacidification wastewater is dried by flue gas drying to achieve salt water separation. However, the above method requires a large amount of high-quality energy such as steam and electricity, the system energy consumption is large and resource utilization cannot be achieved, and the investment cost is high. Utility Model Content

[0003] In order to solve the problem of high energy and water consumption in the process of wet deacidification and saline wastewater treatment in the prior art, the utility model provides a neutralization deacidification and saline wastewater resource utilization system, which can reduce the energy consumption in the process of wet deacidification and saline wastewater treatment, thereby reducing the overall operating cost of the system.

[0004] The technical solution of the utility model is as follows: a neutralization method deacidification salt-containing wastewater resource utilization system, which includes: a cooler shell and an atomizing spray device, characterized in that it also includes: a heat exchange coil, a salt scraper, a centrifuge, and a cooling pool;

[0005] The atomizing spray device, the heat exchange coil and the salt scraper are arranged in the inner cavity of the cooler shell in a top-down order; the salt scraper is arranged at the bottom of the inner cavity of the cooler shell; and a water vapor exhaust port is arranged at the top of the cooler shell;

[0006] The cooling pool is arranged outside the cooler housing and is connected to the liquid supply equipment of the deacidified wastewater;

[0007] The atomizing spraying equipment comprises: a deacidification wastewater inlet and a spray head; the cooling pool is connected to the deacidification wastewater inlet of the atomizing spraying equipment through a circulation pump;

[0008] The heat exchange coil comprises a water inlet and a water outlet for circulating cooling water, the water inlet is arranged below the water outlet, and the water inlet and the water outlet are respectively connected to the water supply equipment for circulating water;

[0009] A crystallized salt discharge port is arranged at the bottom of the cooler shell, the crystallized salt discharge port is connected to the centrifuge, and a liquid discharge port of the centrifuge is connected to the cooling pool.

[0010] It is further characterized by:

[0011] The salt scraper comprises: a scraper and a driving motor, wherein the scraper is arranged on an output shaft of the driving motor;

[0012] The bottom of the cooler shell is a bowl-shaped structure with a concave center. The curvature of the blade of the scraper is adapted to the curvature of the bottom of the cooler shell, and when installed, the blade faces the bottom of the cooler shell and is arranged close to the bottom end surface of the cooler. Through holes are evenly arranged on the back of the scraper.

[0013] An air inlet and a deacidification wastewater overflow port are arranged from top to bottom on the cooler shell between the salt scraper and the heat exchange coil; the deacidification wastewater overflow port is connected to the cooling tank;

[0014] The water inlet of the circulation pump is arranged at the bottom of the cooling pool; the outlet of the circulation pump is provided with a liquid precision filter;

[0015] It also includes: a heat exhaust fan, which is arranged below the exhaust port on the top of the cooler housing;

[0016] It also includes: a water collector and a demisting filler layer, wherein the water collector is arranged between the atomizing spray device and the heat exhaust fan; the demisting filler layer is arranged between the water collector and the heat exhaust fan;

[0017] The water collector comprises: a lining plate and a hood, wherein a through hole is arranged on the lining plate, and a cylinder is arranged on the through hole; the hood is installed above the through hole through a supporting structure, and the size of the hood is larger than the size of the through hole; a concave water collecting tank is arranged at one end of the lining plate, and the water collecting tank is connected to a condensed water recovery device;

[0018] A cooling fan is arranged on the top of the cooling pool.

[0019] The present application provides a neutralization method deacidified salt-containing wastewater resource utilization system, which naturally cools the deacidified wastewater through a cooling pool, thereby reducing the use of electricity resources; the circulating cooling water is connected through a closed heat exchange coil, and the deacidified wastewater enters the cooler for atomization and spraying, and the lower temperature deacidified wastewater is atomized and indirectly cooled and heat-exchanged with the higher temperature cooling water in the heat exchange coil, thereby realizing the evaporation of water vapor in the deacidified wastewater and increasing the salt concentration of the deacidified wastewater. The closed heat exchange coil can ensure that the cooling water and the deacidified wastewater do not mix in liquid, so the cooling water in the technical solution of the present application can simultaneously use the high-temperature liquid that needs to be heat exchanged in the system , which not only realizes the evaporation of the deacidified wastewater but also the cooling of the liquid in the heat exchange coil, further reducing the overall energy consumption of the system; even if industrial water is used as cooling water, it can be reused because it does not mix with the deacidified wastewater, reducing the waste of water resources; a wastewater concentration section is set at the bottom of the inner cavity of the cooler shell, and the high-concentration deacidified wastewater after heat exchange is further naturally cooled in the wastewater concentration section, and the water vapor generated during the natural cooling process is discharged from the top of the cooler shell and then continuously utilized, and the mixture of crystalline salt and wastewater is precipitated for solid-liquid separation, and the separated low-salt liquid is sent to the cooling pool for further cooling and circulation again. The technical solution of this application can repeatedly recycle cooling water without using a large amount of electrical energy, greatly reducing the energy consumption in the process of treating saline wastewater from wet deacidification, thereby reducing the overall operating cost of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the neutralization method deacidification wastewater resource utilization system;

[0021] Figure 2 It is a structural schematic diagram of the water collector;

[0022] Figure 3 It is a schematic diagram of the structure of the main view of the salt scraper;

[0023] Figure 4 A schematic diagram of the structure of a salt scraper from a top view. DETAILED DESCRIPTION

[0024] like Figure 1~Figure 4 As shown, the present application includes a neutralization method deacidification salt wastewater resource utilization system, which includes: a cooler shell 1, an atomizing spray device 2, a heat exchange coil 3, a salt scraper 4, a centrifuge 5, a cooling tank 6, a circulating pump 7, a precision filter 8, a water collector 9, a demisting filler layer 10 and a heat exhaust fan 11.

[0025] The atomizing spray device 2, the heat exchange coil 3 and the salt scraper 4 are arranged in the inner cavity of the cooler shell 1 in a top-down order; the salt scraper 4 is arranged at the bottom of the inner cavity of the cooler shell 1; and the exhaust port 102 of water vapor is arranged at the top of the cooler shell 1. The cooling pool 6 is arranged outside the cooler shell 1 and connected to the liquid supply device of the deacidified wastewater (not marked in the figure). The atomizing spray device 2 includes: a spray pipe and a nozzle 202, one end of the spray pipe is the deacidified wastewater inlet 201, and the nozzle 202 is arranged on the pipe body of the spray pipe. The cooling pool 6 is connected to the deacidified wastewater inlet 201 of the atomizing spray device 2 through a circulating pump 7. The heat exhaust fan 11 is arranged below the exhaust port 102 at the top of the cooler shell 1, and the hot air and steam mixture in the cooler are discharged in time through the heat exhaust fan 11, and the clean condensed droplets generated in the cooling process are collected and reused through the setting of the demisting filler layer 10.

[0026] The deacidified wastewater in the present application is cooled to about 20°C in the cooling pool 6, and is sent to the spray pipe in the cooler shell 1 for atomization spraying, so as to realize indirect cooling of the circulating cooling water coil and heating and evaporation of the deacidified wastewater. In the specific implementation, the heat exchange coil is made of titanium material to prevent corrosion and prevent the deacidified wastewater from polluting the clean circulating cooling water. A cooling fan 601 is arranged on the top of the cooling pool 6 to cool the deacidified saline wastewater and recycle it. After the deacidified wastewater enters the cooling pool, the saturated solubility of the salt will decrease during the cooling process of the saline wastewater, and the high-concentration saline water will fall to the bottom of the pool, further precipitating crystallized salt.

[0027] The water inlet of the circulation pump 7 is arranged at the bottom of the cooling pool 6 ; and the liquid precision filter 8 is arranged at the outlet of the circulation pump 7 .

[0028] The deacidified wastewater in the cooling pool 6 is pumped into the cooler through the circulating pump 7 to exchange heat and cool the circulating cooling water. A precision filter 8 is provided at the outlet of the circulating pump 7. The precision filter 8 adopts a filtration pore size of 300 mesh, which is mainly used to further recover the crystallized salt that may precipitate during the cooling process for subsequent salt resource utilization, and at the same time prevent the crystallized salt from clogging the spray pipe of the atomizing spray equipment 2 in the cooler.

[0029] The water inlet of the circulation pump 7 is arranged at the bottom of the cooling pool 6. On the one hand, it can effectively collect the crystallized salt deposited at the bottom of the cooling pool 6. On the other hand, it utilizes the different densities of cold and hot water and the principle that the cold water is at the bottom to pump the cold water back to the cooler for recycling, while the hot water continues to cool down, thereby preventing the cooling amount of the circulating cooling water in the cooler from failing to meet the heat exchange conditions, resulting in the occurrence of problems such as high operating power and high energy consumption of the heat exhaust fan 11.

[0030] The heat exchange coil 3 includes a water inlet 301 and a water outlet 302 for circulating cooling water, the water inlet 301 is arranged below the water outlet 302, and the water inlet 301 and the water outlet 302 are respectively connected to the water supply equipment (not marked in the figure) of the cooling circulating water. The circulating cooling water with a higher temperature enters from bottom to top, and the temperature of the coil at the bottom is higher. The deacidification wastewater spray with a lower temperature sprays from top to bottom, and the water in the wastewater will gradually evaporate when heated; the deacidification wastewater spray meets and exchanges heat with the heat exchange coil with higher and higher temperature during the descent process, which effectively increases the evaporation of water in the deacidification wastewater, thereby increasing the salt concentration of the deacidification wastewater falling to the bottom.

[0031] In this embodiment, the circulating cooling water in the heat exchange coil uses the high-temperature cooling water after heat exchange output by the rotating shaft of the large equipment in the same system or the mechanical seal cooling equipment, and the temperature is about 30-40°C. The 20°C deacidified wastewater coming out of the cooling pool meets the heat exchange coil with a higher temperature after atomization. The water in the deacidified wastewater mist evaporates when heated, increasing the salt concentration of the deacidified wastewater. The high-concentration salt-containing wastewater falls into the wastewater concentration part 105 below the cooler shell. After the high-temperature cooling water is cooled, it is sent back to the rotating shaft or mechanical seal cooling equipment for use, without wasting other water resources, thereby reducing the overall cost of the system.

[0032] The salt-containing wastewater after evaporation and concentration after heat exchange with the circulating cooling water falls into the wastewater concentration part 105 at the bottom of the inner cavity of the cooler shell 1. A part of the wastewater will evaporate after absorbing heat and be carried out by the heat exhaust fan at the top of the cooler. Therefore, the deacidified wastewater collected at the bottom of the cooler will be concentrated, and the salt content will be further increased. After a long period of operation, the crystallized salt precipitated at the bottom of the cooler is discharged out of the tower through the rotating salt scraper 4 arranged at the bottom of the cooler for collection and utilization.

[0033] An air inlet 102 and a deacidification wastewater overflow port 101 are arranged from top to bottom on the cooler housing 1 between the salt scraper 4 and the heat exchange coil 3 ; the deacidification wastewater overflow port 101 is connected to the cooling tank 6 .

[0034] An air inlet 102 is arranged above the wastewater concentration section 105; in specific applications, the air inlet 102 is arranged based on the shutter, and natural wind is introduced to improve the cooling efficiency of the salt water stored in the wastewater concentration section 105. After the mist-like high-salt wastewater sprayed by the nozzle 202 exchanges heat with the heat exchange coil 3, it continues to fall downward to the wastewater concentration section 105 at the bottom of the cooler shell 1. During the dripping process, the natural wind introduced by the air inlet 102 cools the falling wastewater, which greatly improves the cooling efficiency of the wastewater, and does not need to use other energy sources such as electricity, thereby reducing the energy consumption of the system.

[0035] The deacidified wastewater after heat exchange stored in the wastewater concentration section 105 has a higher salt concentration in the lower part and a lower salt concentration in the upper part. When the height of the deacidified wastewater reaches the height of the set deacidified wastewater overflow port 10, the deacidified wastewater will enter the cooling pool 6 through the deacidified wastewater overflow port 10 for circulation, cooling and concentration. The setting of the deacidified wastewater overflow port 10 at the bottom of the cooler controls the storage amount of wastewater stored in the wastewater concentration section 105, prevents excessive wastewater due to blockage and other reasons, and affects the heat exchange process above the cooler. At the same time, the low-salt wastewater in the wastewater concentration section 105 is introduced into the cooling pool and circulated again for salt extraction.

[0036] A crystallized salt discharge port 106 is provided at the bottom of the cooler housing 1 , and the crystallized salt discharge port is connected to the centrifuge 5 , and a liquid discharge port of the centrifuge 5 is connected to the cooling pool 6 .

[0037] like Figure 3 and 4 As shown, the salt scraper 4 includes: a scraper 401 and a drive motor 402, the scraper 401 is arranged on the output shaft 404 of the drive motor 402, and the output shaft 404 of the drive motor 402 is arranged vertically. The bottom of the cooler shell is a bowl-shaped structure with a concave center, and the crystallized salt discharge port 106 is arranged near the bottom of the bowl to ensure that the crystallized salt mixture with a higher density can be naturally deposited and concentrated near the crystallized salt discharge port; the curvature of the blade of the scraper 401 is adapted to the curvature of the bottom of the cooler shell 1, and the blade is facing the bottom of the cooler shell during installation, and the blade is arranged close to the end face of the bottom of the cooler shell. The cross-section of the bottom of the cooler shell in this embodiment is circular, the rotating axis of the scraper 401 is arranged at the center of the circle, and the length of the scraper 401 is adapted to the radius of the bottom of the cooler shell.

[0038] When the driving motor 402 is started, the scraper 401 is driven to rotate slowly along the bottom of the cooler shell 1, and the blade scrapes the crystallized salt precipitated on the bottom of the shell, and the mixed solution of the scraped crystallized salt and concentrated hydrochloric acid is discharged along the crystallized salt discharge port at the bottom to the centrifuge 5. In this embodiment, four scrapers 401 are arranged in a cross shape to ensure that the crystallized salt at the bottom can be scraped off evenly without dead angles.

[0039] The through holes 403 are evenly arranged on the back of the scraper 401, which can not only reduce the overall weight of the scraper, but also prevent the scraper 401 from causing excessive stirring to the deacidified wastewater after heat exchange stored in the wastewater concentration section 105 when rotating, thereby ensuring that the crystalline salt mixed solution with higher density can naturally flow to the bottom of the bowl-shaped structure based on its higher density and be discharged from the crystalline salt discharge port.

[0040] The crystallized salt discharged from the bottom of the cooler by the rotating salt scraper 4 is centrifuged into the high-salt concentrated water centrifuge 5 for solid-liquid separation, and the salt after solid-liquid separation can be further utilized as a resource. The low-salt water discharged after solid-liquid separation in the high-salt concentrated water centrifuge 5 enters the cooling pool for recycling.

[0041] The water collector 9 is arranged between the atomizing spray device 2 and the heat exhaust fan 11; the demisting filler layer 10 is arranged between the water collector 9 and the heat exhaust fan 11. Figure 2 As shown, the water collector 9 includes: a supporting plate 901 and a hood 903, the supporting plate 901 is provided with a through hole 902, and a cylinder 904 is provided on the through hole 902; the hood 903 is installed above the through hole 902 through a rod-shaped supporting structure (not marked in the figure), and the size of the hood 903 is larger than the size of the through hole 902; a concave water collecting trough 905 is provided at one end of the supporting plate 901, and the water collecting trough 905 is connected to a condensed water recovery device (not marked in the figure).

[0042] The water vapor generated by the deacidified wastewater after heat exchange with the cooling circulating water in the heat exchange coil 3 and the water vapor generated by the deacidified wastewater cooled in the salt-containing wastewater concentration section rises from the through hole 902 to the top of the backing plate 901. The wind cap 903 is larger than the through hole 902, and the steam is diverted and dispersed. At the same time, once the steam condenses and drips from the wind cap 903 during the rising process, it will not fall into the through hole 902 below, but drip on the backing plate 901. A water collection tank 905 is set on one side of the backing plate 901 to send the collected condensed water to the condensed water recovery device. In this application, the water collector 9 is set to prevent the condensed water collected by the demisting filler from falling into the bottom of the cooler, so as to achieve the separate collection of clean condensed water.

[0043] The method for resource utilization of deacidification wastewater based on the neutralization method deacidification wastewater resource utilization system comprises the following steps.

[0044] S1: Cooling of deacidification wastewater;

[0045] The deacidified wastewater is sent to the cooling pool 6 for transfer and storage, and then sent to the cooler after being cooled to a preset temperature in the cooling pool 6; part of the crystallized salt is precipitated during the cooling in the cooling pool 6 for recovery.

[0046] S2: Deacidification wastewater is evaporated by heat exchange to increase the salt concentration of deacidification wastewater;

[0047] A closed heat exchange coil 3 is arranged in the cooler; after the deacidified wastewater is cooled, it is sent into the cooler and then subjected to atomization spraying treatment to indirectly exchange heat and cool it with the circulating cooling water in the heat exchange coil 3; the atomized deacidified wastewater exchanges heat with the circulating cooling water at a higher temperature, and the water in the deacidified wastewater is evaporated to obtain deacidified wastewater with a higher concentration.

[0048] S3: precipitation of impurity salts;

[0049] A wastewater concentration section 105 is arranged below the heat exchange coil 3 in the cooler. The deacidified wastewater after heat exchange falls into the salt-containing wastewater concentration section 105 for cooling, and crystallized salt is precipitated at the bottom.

[0050] In step S2 and step S3, the steam generated by heat exchange between the deacidified wastewater and the cooling circulating water in the heat exchange coil 3 and the steam generated by cooling the deacidified wastewater in the salt-containing wastewater concentration section are recovered and reused.

[0051] S4: brine separation;

[0052] The high-concentration crystallized salt mixed liquid at the bottom of the wastewater concentration section is sent out of the cooler for solid-liquid separation process, and the separated low-salt waste liquid is sent to the cooling pool 6 again, and the separated solid crystallized salt is recycled.

[0053] S5: Steps S1 to S4 are executed cyclically, the salt concentration of the deacidified wastewater in the cooling pool gradually increases, and the precipitated solid crystalline salt is recycled as a resource.

[0054] Desulfurization wastewater generally contains about 5% of mixed salt, mainly sodium chloride and sodium sulfate. Since the specific heat capacity of salt water is small, the specific heat capacity of conventional water is 4.18j / (g℃), and the specific heat capacity of 10% salt water is 3.47j / (g℃). Therefore, compared with conventional low-hardness and low-salinity process water, the heat capacity absorbed by desulfurization wastewater is smaller, and the amount of desulfurization wastewater that can be consumed is larger.

[0055] In the cooling equipment in the prior art, a packing layer is set under the spray pipe. In the present application, coil indirect cooling is adopted, and no packing layer is set under the spray pipe. Compared with the prior art, the setting of the present application increases the gas-liquid contact area and is not easy to be blocked, thereby ensuring that the separation of salt and water is easier to achieve in the cooler in the present application.

[0056] The saturated solubility of sodium chloride is 36.0g / 100g water at 20℃, and the saturated solubility of sodium sulfate is 19.5g / 100g water at 20℃. The deacidification wastewater is cooled by about 10℃. Every 1kg of circulating cooling water can evaporate 17g of water from the saline wastewater. After 5 cycles of 0.1kg of saline deacidification wastewater, the salt concentration can be increased to more than 33.33%, thereby separating the salt precipitation.

Claims

1. A neutralization deacidification salt wastewater resource utilization system, comprising: The cooler housing and atomizing spray equipment are characterized in that they also include: a heat exchange coil, a salt scraper, a centrifuge, and a cooling pool; The atomizing spray device, the heat exchange coil and the salt scraper are arranged in the inner cavity of the cooler shell in a top-down order; the salt scraper is arranged at the bottom of the inner cavity of the cooler shell; and a water vapor exhaust port is arranged at the top of the cooler shell; The cooling pool is arranged outside the cooler housing and is connected to the liquid supply equipment of the deacidified wastewater; The atomizing spraying equipment comprises: a deacidification wastewater inlet and a spray head; the cooling pool is connected to the deacidification wastewater inlet of the atomizing spraying equipment through a circulation pump; The heat exchange coil comprises a water inlet and a water outlet for circulating cooling water, the water inlet is arranged below the water outlet, and the water inlet and the water outlet are respectively connected to the water supply equipment for circulating water; A crystallized salt discharge port is arranged at the bottom of the cooler shell, the crystallized salt discharge port is connected to the centrifuge, and a liquid discharge port of the centrifuge is connected to the cooling pool.

2. According to claim 1, a neutralization deacidification salt wastewater resource utilization system is characterized by: The salt scraper comprises: a scraper and a driving motor, wherein the scraper is arranged on an output shaft of the driving motor; The bottom of the cooler shell is a bowl-shaped structure with a concave center. The curvature of the scraper blade is adapted to the curvature of the bottom of the cooler shell, and when installed, the blade faces the bottom of the cooler shell and is set close to the bottom end face of the cooler. Through holes are evenly opened on the back of the scraper.

3. According to claim 1, a neutralization method deacidification salt wastewater resource utilization system is characterized by: An air inlet and a deacidification wastewater overflow port are arranged from top to bottom on the cooler shell between the salt scraper and the heat exchange coil; the deacidification wastewater overflow port is connected to the cooling pool.

4. According to claim 1, a neutralization deacidification salt wastewater resource utilization system is characterized by: The water inlet of the circulation pump is arranged at the bottom of the cooling pool; and a liquid precision filter is arranged at the outlet of the circulation pump.

5. According to claim 1, a neutralization deacidification salt wastewater resource utilization system is characterized by: It also includes: a heat exhaust fan, which is arranged below the exhaust port on the top of the cooler shell.

6. A neutralization deacidification salt wastewater resource utilization system according to claim 5, characterized in that: It also includes: a water collector and a demisting filler layer, wherein the water collector is arranged between the atomizing spray device and the heat exhaust fan; and the demisting filler layer is arranged between the water collector and the heat exhaust fan.

7. A neutralization deacidification salt wastewater resource utilization system according to claim 6, characterized in that: The water collector includes: a supporting plate and a hood, the supporting plate is provided with a through hole, and a cylinder is provided on the through hole; the hood is installed above the through hole through a supporting structure, and the size of the hood is larger than the size of the through hole; a concave water collecting trough is provided at one end of the supporting plate, and the water collecting trough is connected to a condensed water recovery device.

8. According to claim 1, a neutralization deacidification salt wastewater resource utilization system is characterized by: A cooling fan is arranged on the top of the cooling pool.

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