A RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater

Abstract

The present invention relates to an RO concentrated water refined slurry device for zero discharge of wet desulfurization wastewater. An atomizing spray layer is provided on the upper part of the separation cylinder, and the inlet of the atomizing spray layer is externally connected to the RO concentrated water inlet channel; a spiral venturi device is provided in the middle part of the separation cylinder; a suction pipe extends to the outside of the separation cylinder and is connected to the lower end of the heating cylinder, and the upper end of the heating cylinder is connected to the separation cylinder from the tangent direction through a tangential connecting pipe; a high-temperature steam inlet is provided on the upper part of the heating cylinder; the steam discharge passage is connected to the steam outlet at the top of the separation cylinder, and is divided into two paths, which are respectively wound and fixed on the heating cylinder and the suction pipe, and each of the two paths has a condensed water outlet. The present invention cleverly designs the atomizing spray, the spiral venturi tube and its extension tube, and the contoured agitator; the steam leaving the separation cylinder is then passed through the forced liquid circulation channel for heat exchange, which can not only accelerate the condensation of steam, but also improve energy efficiency.

Description

Technical Field

[0001] The invention relates to an industrial salt purification and refining crystal slurry device, in particular to a waste salt purification and refining crystal slurry device for zero discharge of desulfurization waste water. Background Art

[0002] Limestone / lime-gypsum desulfurization is a widely used desulfurization method with high efficiency, reliability, stability, safety and low operating cost. It has long been the main method for flue gas desulfurization of coal-fired boilers in thermal power plants. However, this method has a large problem in wastewater treatment. The wastewater produced by desulfurization contains a large amount of chloride ions, sulfate ions, calcium, magnesium ions, etc. The wastewater quality is complex, mainly containing suspended matter, sulfates, supersaturated sulfites, and heavy metals and other impurities. Many of them are the first-class pollutants that are strictly required to be controlled in national environmental protection standards. It has become the most difficult wastewater to treat in coal-fired power plants and is the key to achieving zero wastewater discharge in coal-fired power plants.

[0003] The technologies related to the zero-discharge process of desulfurization wastewater mainly include pretreatment (removal of heavy metals, hardness, etc.), concentration reduction, and evaporation crystallization. Desulfurization wastewater pretreatment and concentration usually use one or several technologies in combination to obtain concentrated RO waste liquid. However, there is no particularly suitable device for the crystallization of concentrated RO waste liquid. Most of them use vacuum cascade continuous crystallizers in the food or pharmaceutical industry. Due to the low saturation of NaCl content, the crystal size cannot be controlled, and there is often too much mother liquor and insufficient concentration. It is expensive and not applicable, which increases the difficulty of subsequent treatment processes and cannot be converted into reasonable economic benefits.

[0004] In the prior art, according to the characteristics of desulfurization wastewater composition, the main component is a NaCl impure solution with low saturation through the pre-stage softening device and RO concentration, which can meet the crystallization requirements without a high-precision vacuum environment. In addition, due to the poor dust filtration of the flue gas inlet, the dust concentration at the inlet is high, and the tar or asphalt dust is very high, resulting in the ineffective crystallization of the RO concentrate, the phenomenon of mother liquor over-flow, and often precipitation and adhesion at the bottom of the reactor. This low-quality slurry cannot meet the requirements of the lower process of zero wastewater discharge, which increases the difficulty of treatment on the one hand and the overall energy consumption on the other. Summary of the invention

[0005] The purpose of the present invention is to provide an RO concentrated water refined slurry device for zero discharge of wet flue gas desulfurization wastewater, which not only combines high-temperature steam, but also cleverly designs upper layer atomization spray, middle layer spiral venturi tube + extension tube to accelerate crystallization, and bottom contour stirrer to accelerate crystallization; and the steam leaving the separation cylinder is then heat exchanged with the forced liquid circulation channel, which can not only accelerate steam condensation, but also improve the energy efficiency of thermal energy use.

[0006] The present invention adopts the following technical solutions:

[0007] A RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater, comprising a separation cylinder 1, a gas-liquid mixing circulation passage, and a steam discharge passage; an atomizing spray layer 105 is provided on the upper part of the separation cylinder 1, and the inlet of the atomizing spray layer 105 is externally connected to the RO concentrated water inlet channel; a funnel-shaped spiral venturi device 106 containing a threaded guide groove is provided in the middle of the separation cylinder 1, and the lower end of the spiral venturi device 106 extends to the bottom area of ​​the separation cylinder 1 through an extension pipe; a special-shaped agitator 108 that imitates the conical bottom of the separation cylinder is provided at the bottom of the separation cylinder 1; the gas-liquid mixing circulation passage includes a nozzle extending into the separation cylinder 1; a nozzle 108 is provided at the bottom of the separation cylinder 1; the gas-liquid mixing circulation passage includes a nozzle 108 extending into the separation cylinder 1; a nozzle 108 is provided at the bottom of ... A suction pipe 107 in the liquid in the cylinder extends to the outside of the separation cylinder and is connected to the lower end of the heating cylinder 4. The upper end of the heating cylinder 4 is connected to the separation cylinder 1 tangentially through a tangential connecting pipe 103, and the connected portion is located between the atomizing spray layer 105 and the spiral venturi device 106 in the height direction; a high-temperature steam inlet 102 is provided on the upper part of the heating cylinder 4; a forced circulation pump 5 is provided on the suction pipe 107, and the steam exhaust passage is connected to the steam outlet at the top of the separation cylinder 1, and is divided into two paths, which are respectively wound and fixed on the heating cylinder 4 and the suction pipe 107, and the two paths each have a condensed water outlet 2.

[0008] Preferably, the high-temperature steam inlet 102 has a pair, which are respectively located in the tangential direction of both sides of the heating cylinder 4.

[0009] Preferably, the portion of the suction pipe 107 extending into the interior of the separation cylinder is a sunken structure; and the forced circulation pump 5 is an axial flow pump.

[0010] Preferably, the top of the separation cylinder 1 is also provided with a spare port 6 for steam discharge or material addition.

[0011] Preferably, the tangential direction in which the tangential connecting pipe 103 communicates with the heating cylinder 4 is consistent with the thread rotation direction of the spiral venturi device 106 .

[0012] Preferably, an inspection hole 3 is provided at the bottom of the separation cylinder 1 .

[0013] Preferably, the special-shaped agitator 108 adopts a variable frequency motor.

[0014] Preferably, a grid separator 104 is provided in the separation cylinder 1 above the atomizing spray layer 105 .

[0015] Preferably, a filter screen is provided at the mouth of the suction pipe 107 .

[0016] The beneficial effects of the present invention are:

[0017] 1) The ingenious design of the upper layer atomization spray, the middle layer spiral venturi tube + extension tube accelerates crystallization, and the bottom profile stirrer accelerates crystallization;

[0018] 2) The steam leaving the separation cylinder is then passed through the forced liquid circulation channel for heat exchange, which can not only accelerate the condensation of steam, but also improve the energy efficiency of thermal energy use; effectively utilize the existing boiler high-temperature steam, reuse the exhaust steam, and save energy.

[0019] 3) The structure is simple and reliable, the crystallization conditions are relatively stable and easy to control, the crystallization can always be carried out at a low supersaturation, and the crystal particle size is easy to control.

[0020] 4) No need to add seed crystals, and technologies such as fine crystal elimination and clear mother liquor overflow can be used to enable the device to have means to control product particle size distribution and slurry density, so that the main crystal particle size is stable, the amount of mother liquor is small, and the production intensity is high. ;

[0021] 5) Evaporation and cooling are carried out simultaneously, which can reach a very low temperature and is not limited by the cooling water temperature, so the production capacity is large and the product quality is stable;

[0022] 6) The suction port of the axial flow pump is set in the brine area. First, the Venturi tube is used to ensure the slurry circulation route, stabilize the crystal growth time, and is conducive to the stability of crystallization. Second, the sinking suction port is set to reduce the coarse particles of the forming slurry from being sucked into the axial flow pump;

[0023] 7) Use an axial flow pump to deliver the slurry to the container in a tangential direction and just generate a vortex in the spiral venturi tube to accelerate the effective time of cooling crystallization.

[0024] 8) The RO concentrated liquid enters the lower part of the separation chamber of the separation cylinder through the atomizing spray layer. The atomizing spray layer can evenly atomize the slurry into small droplets for full contact with the steam, accelerate the stripping of water, effectively evaporate the water content in the slurry, and promote the concentration of brine.

[0025] 9) The frequency conversion agitator in the slurry zone has a wall-scraping special-shaped impeller, and the speed can be adjusted within the range of 0-250rpm. On the one hand, it can prevent the slurry from settling on the wall, and on the other hand, it can control the product particle size distribution and slurry density through the number of revolutions.

[0026] 10) The subsequent centrifugal equipment and the drying device shown can effectively store and purify sodium chloride salt to meet the secondary standard of industrial dry salt. It has the function of zero wastewater discharge and obvious economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a front perspective view of the RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to the present invention.

[0028] Figure 2 It is a schematic diagram of the double tangential air intake of the high-temperature steam inlet relative to the heating cylinder.

[0029] Figure 3 It is a schematic diagram of a single tangential gas / liquid inlet of a tangential connecting pipe relative to a heating cylinder.

[0030] Figure 4 It is a plan view of the atomizing spray layer.

[0031] Figure 5 It is an enlarged view of the special-shaped agitator at the bottom of the separation cylinder.

[0032] In the figure, 1. separation cylinder, 2. condensate outlet, 3. inspection hole, 4. heating cylinder, 5. forced circulation pump, 6. spare port; 101. exhaust steam heat exchange device, 102. high-efficiency steam distributor, 103. cut-angle inlet, 104. grid separator, 105. atomizing spray layer, 106. threaded venturi device, 107. suction port, 108. special-shaped agitator. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] See also Figure 1-Figure 4 A device for purifying and refining crystal slurry with zero discharge of waste salt from desulfurization wastewater comprises a heating cylinder 4 and a separation cylinder 1. The upper part of the separation cylinder 1 is a separation chamber, which includes a grid separator 104 and an atomizing spray layer 105. The separation cylinder 1 is provided with a threaded Chen-type venturi tube, the lower part is a brine area, and the upper side of the brine area is provided with a downward-sinking suction pipe 107 with a downward-facing pipe mouth, which is externally connected to a forced circulation axial flow pump. Steam is discharged through the outlet at the top of the separation cylinder container.

[0035] See also Figure 1 The hot RO concentrated liquid enters the separation cylinder 1 through the atomizing spray layer 105 at the bottom of the separation zone; and the crystal slurry is continuously discharged from the outlet at the bottom of the cone. A variable frequency special-shaped agitator 108 is set at the bottom to produce a stirring effect in the device and prevent the crystal slurry from settling on the wall. An inspection hole 3 is set on the side wall.

[0036] See also Figure 1 A waste steam heat exchange device 101 is provided at the feed inlet of the forced circulation axial flow pump, and the waste steam heat is used again for heating before the axial flow pump.

[0037] See also Figure 2 A high-temperature steam distributor is provided at the high-temperature steam inlet of the heating cylinder, and the high-temperature steam is introduced in a double tangential direction through the high-temperature true gas distributor 102.

[0038] See also Figure 2 The top of the heating cylinder 4 enters the inlet 103 in the tangential direction to send the medium into the separation cylinder and just generate a vortex in the spiral venturi tube.

[0039] See also Figure 1The inner wall of the spiral venturi tube 106 adopts a threaded guide groove to better guide the vortex of the medium and produce a high-speed centrifugal effect, thereby accelerating the effective time of cooling crystallization.

[0040] See also Figure 1 The bottom of the spiral venturi tube sinks to the bottom slurry area of ​​the separation cylinder. The slurry must pass through the slurry area to start crystal growth. Part of the brine is layered to the upper part.

[0041] In this embodiment, the bottom special-shaped agitator 108 is controlled by frequency conversion speed regulation to adjust the speed within the range of 0-250rpm, and the agitator impeller is provided with a wall-scraping special-shaped impeller (two-blade or three-blade), and the impeller is made of wear-resistant material.

[0042] During specific operation, the hot RO concentrated liquid enters the separation cylinder through the atomizing spray layer 105 at the bottom of the separation chamber, and the high-temperature steam enters tangentially from the feed port in the middle of the heating cylinder. It is preliminarily mixed in the heating cylinder, and under the action of the forced circulation axial flow pump, it enters the separation cylinder in a tangential manner and just generates a vortex in the spiral venturi tube 106, and passes through the threaded guide groove on the inner wall of the spiral venturi tube 106 to produce a high-speed centrifugal effect. Finally, the special-shaped agitator at the bottom gradually crystallizes and precipitates to form crystal slurry, which is discharged timely through the discharge port, and the excess steam and water are discharged through the grid separator at the upper part of the separation cylinder.

[0043] in:

[0044] Exhaust steam heat exchange device 101: Tube-wound heat exchanger. The exhaust steam from the separation cylinder is heat exchanged by the tube-wound heat exchanger to preliminarily heat the brine entering the forced circulation axial flow pump. The material is made of wear-resistant material.

[0045] High temperature steam distributor 102: Figure 1 , adopts double tangential air intake method to make the internal plate of the heating cylinder have no dead angle, the mixed heating is more uniform, etc., which can form turbulence.

[0046] Cut corner entry 103: Figure 1 The circulating crystal liquid adopts a one-way side tangential liquid inlet method, which flushes at high speed to avoid sedimentation and scaling. In addition, a vortex can be generated in the separation cylinder and just in the spiral Venturi tube.

[0047] Grid separator 104: This device can effectively filter the crystal liquid in the exhaust steam, while providing gas-liquid contact, effectively evaporating the water content in the slurry and reducing the leakage of crystal salt.

[0048] Atomization spray layer 105: This device can evenly atomize the slurry into small droplets for full contact with steam, effectively evaporating the water in the slurry and promoting brine concentration.

[0049] Threaded Venturi Tube 106: Also known as Chen-style Venturi Tube, this device is simulated and calculated for the medium. The inner wall adopts threaded guide grooves to better guide the vortex of the medium and produce high-speed centrifugal effect, accelerating the effective time of cooling crystallization. The lower outlet sinks to the crystal slurry area to guide the slurry to sink.

[0050] The downward suction pipe 107 is equipped with a 2205 alloy filter screen. On the one hand, it cooperates with the Venturi tube to ensure the slurry circulation route, stabilize the crystal growth time, and is beneficial to the stability of crystallization. On the other hand, it reduces the coarse particles of the formed crystal slurry from being sucked into the axial flow pump.

[0051] The variable frequency special-shaped agitator 108 includes a variable frequency speed regulating motor, a transmission device, a special-shaped stirring impeller and other components. The variable frequency speed regulation can control the speed to be adjusted within the range of 0-250rpm. The stirring impeller can be set to a 2-stage or 3-stage impeller according to the physical properties. The impeller is made of wear-resistant material and can be a ceramic-coated impeller.

[0052] The RO concentrated water refined slurry device for zero discharge of wet flue gas desulfurization wastewater in this embodiment not only combines high-temperature steam, but also cleverly designs the upper layer atomization spray, the middle layer spiral venturi tube + extension tube to accelerate crystallization, and the bottom contour agitator to accelerate crystallization; and the steam leaving the separation cylinder is then heat exchanged with the forced liquid circulation channel, which can not only accelerate steam condensation, but also improve the energy efficiency of thermal energy use.

[0053] The above are preferred embodiments of the present invention. A person skilled in the art may make various changes or improvements on this basis. Without departing from the general concept of the present invention, these changes or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater, characterized in that : It comprises a separation cylinder (1), a gas-liquid mixing circulation passage, and a steam exhaust passage; The upper part of the separation cylinder (1) is provided with an atomizing spray layer (105), and the inlet of the atomizing spray layer (105) is externally connected to the RO concentrated water inlet channel; the middle part of the separation cylinder (1) is provided with a funnel-shaped spiral venturi device (106) containing a threaded guide groove, and the lower end of the spiral venturi device (106) extends to the bottom area of ​​the separation cylinder (1) through an extension pipe; the bottom of the separation cylinder (1) is provided with a special-shaped agitator (108) that imitates the conical bottom of the separation cylinder; the gas-liquid mixing circulation passage includes A suction pipe (107) is provided which extends into the liquid in the separation cylinder. The suction pipe (107) extends to the outside of the separation cylinder and is connected to the lower end of the heating cylinder (4). The upper end of the heating cylinder (4) is connected to the separation cylinder (1) in a tangential direction through a tangential connecting pipe (103). The connecting portion is located between the atomizing spray layer (105) and the spiral venturi device (106) in the height direction. A high-temperature steam inlet (102) is provided on the upper part of the heating cylinder (4). A forced circulation pump (5) is provided on the suction pipe (107). The steam discharge passage is connected to the steam outlet at the top of the separation cylinder (1) and is divided into two paths, which are respectively wound and fixed on the heating cylinder (4) and the suction pipe (107), and each of the two paths has a condensed water outlet (2); The part of the suction pipe (107) extending into the interior of the separation cylinder is a sunken structure; the forced circulation pump (5) is an axial flow pump; The tangential direction in which the tangential connecting pipe (103) communicates with the heating cylinder (4) is adapted to the thread rotation direction of the spiral venturi device (106).

2. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that The high-temperature steam inlet (102) has a pair, which are respectively located in the tangential direction on both sides of the heating cylinder (4).

3. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that The top of the separation cylinder (1) is also provided with a spare port (6) for steam discharge or material addition.

4. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that The bottom of the separation cylinder (1) is provided with an inspection hole (3).

5. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that The special-shaped agitator (108) adopts a variable frequency motor.

6. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that A grid separator (104) is arranged in the separation cylinder (1) above the atomizing spray layer (105).

7. The RO concentrated water refining slurry device for zero discharge of wet desulfurization wastewater according to claim 1, characterized in that The pipe opening of the suction pipe (107) is provided with a filter screen.

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