Metal ion micro-interface induced crystallization separation device and method in high-salinity wastewater

Abstract

The present application relates to the technical field of high-salinity wastewater, and particularly relates to a device and a method for separating metal ions in high-salinity wastewater by micro-interface induced crystallization. The present application provides a device for separating metal ions in high-salinity wastewater by micro-interface induced crystallization, which comprises a cylinder, and a fluid mixing zone, a circulating granulation zone and a particle separation zone are sequentially arranged in the cylinder from bottom to top. The device for separating metal ions in high-salinity wastewater by micro-interface induced crystallization provided by the present application helps high-salinity wastewater to enter the upper space of the gas-liquid distributor at different speeds with the help of the differential-speed gas-liquid distributor; meanwhile, more crystalline particles are sent to the circulating granulation zone, the flow direction of the seed crystal in the circulating granulation is regulated, and the crystallization efficiency of the seed crystal is improved. The fluidization zone is designed to be wide at the bottom and narrow at the top, the cross-sectional area of the flow channel of the upper fluidization zone is increased, more sufficient reaction space is provided for the crystalline particles, the drag force of the fluid on the seed crystal particles is weakened, and the residence time of the crystalline particles in the upper fluidization zone is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-salinity wastewater, in particular to a device and method for separating metal ions in high-salinity wastewater by micro-interface induced crystallization. BACKGROUND

[0002] High-salinity wastewater refers to wastewater with a total salt content of not less than 1%, and the mass fraction of total dissolved solids and organic matter is usually not less than 3.5%. High-salinity wastewater has a wide range of sources and complex components. For example, coal gasification washing wastewater, circulating water system drainage, and reverse osmosis concentrated water in the production process of coal chemical industry have the characteristics of high suspended solids content, high total dissolved solids content, high hardness, and high alkalinity; wet desulfurization wastewater, cooling water, and washing wastewater in the production process of metallurgical and electroplating industry have the characteristics of high heavy metal content, high ammonia nitrogen and hardness, high organic matter content, and high acid and alkalinity; chemical synthesis pharmaceutical wastewater, antibiotic pharmaceutical wastewater, and traditional Chinese medicine pharmaceutical wastewater in the production process of pharmaceutical industry have the characteristics of high suspended solids content, high organic matter content, and high inorganic salt content; washing water, soaking liquid, extraction liquid, and waste electrolyte in the production and recovery process of new energy battery industry have the characteristics of high heavy metal content, high organic matter content, and high ammonia nitrogen and acid and alkalinity. The metal ions existing in large quantities in high-salinity wastewater include Ca 2+ , Mg 2+ , Fe 2+ , Mn 2+ , Ni 2+ , etc., which are extremely harmful to the ecological environment and human health. Separation and recovery of metal ions in high-salinity wastewater are of great significance to solving water resource shortage and environmental pollution problems.

[0003] After pretreatment to remove suspended solids, oils, and organic matter, high-salinity wastewater is generally separated by the method of concentration and desalination + crystallization solidification. Common crystallization solidification technologies include evaporation crystallization, cooling crystallization, membrane distillation crystallization, and nanofiltration separation crystallization. Among them, the evaporation crystallization technology is simple to operate, but the equipment structure is complex and the energy consumption is high; the cooling crystallization technology has high production efficiency, but the operation and maintenance cost is high and the material requirements are strict; the membrane distillation crystallization technology is simple in equipment and easy to operate, but the membrane material cost is high and the performance is not stable; the nanofiltration separation crystallization technology can selectively crystallize and has high product purity, but the membrane is easy to block and the maintenance cost is high.

[0004] In the face of the development trend of process production reduction and high efficiency, the new induced crystallization technology combines the characteristics of concentration and desalination and crystallization solidification. It has attracted widespread attention due to its advantages of simple operation, low cost, high efficiency, no secondary pollution, and easy recovery of crystallization products.

[0005] For example, CN105502692A discloses a chemical crystallization circulating granulation fluidized bed water treatment device. It is equipped with a water distribution zone, a chemical distribution zone, a granulation zone, and a clear water zone. By improving the chemical dosing layer and adding an inner and outer cylinder to form a double-layer structure, it promotes the circulating fluidization of seed crystals, improving crystallization efficiency. The crystallized particles are discharged from the bottom after growth. CN111498967A discloses a crystallization fluidized bed for wastewater defluorination, phosphorus removal, and hardness removal. With a constant overall bed flow rate, an improved differential speed water distributor allows crystal particles to grow further in a dynamic process: sinking in a low-velocity zone, being entrained in a high-velocity zone and floating, and then migrating back to a low-velocity zone to sink, thus improving crystallization efficiency. CN106044997B discloses an Fe-containing... 3+ Treatment methods for heavy metal wastewater. One method involves using a reducing agent to remove Fe from the wastewater. 3+ Reduced to Fe 2+ Then, Fe is removed and recovered through induced crystallization. 2+ And other heavy metal ions. CN115583706A discloses a chemical crystallization circulating granulation fluidized bed water treatment device. It features a two-stage annular dosing pipe to achieve gradient feeding of sodium hydroxide and sodium carbonate, and a pressure detection system to automate the discharge of crystallized particles and the addition of seed crystals. An external transmission pipe effectively alleviates scaling caused by water stagnation during equipment shutdowns or when water supply is insufficient. CN116177762A discloses an internal pressure self-circulating heterogeneous crystallization fluidized bed water treatment device. The interior of the cylinder is divided into an inlet zone, a reagent mixing zone, a reaction reflux zone, and a sedimentation separation zone from bottom to top. The upper side of the reaction zone is connected to the reflux zone via a guide pipe, and the bottom of the reflux zone is connected to the bottom of the reaction zone via a reflux pipe, achieving internal circulation fluidization of seed crystals and improving crystallization efficiency. CN116924533A discloses a nucleus crystal granulation method for precise separation of high-valence metal ions in high-salt wastewater. N-stage tandem nucleogranulation equipment enables the sequential crystallization of N high-valence metal ions onto N characteristic seed crystals, thereby achieving precise separation and recovery of N metal ions. CN116947185A discloses a nucleogranulation water treatment device and system. Wastewater enters from the bottom of a horizontally placed reaction cylinder, reacts counter-currently with reagents entering from the top, and crystallizes onto seed crystals filled inside the reactor. According to water purification requirements, a return pipe is selectively connected between the drain and inlet, and a seed crystal filter interception structure is installed at the drain to prevent seed crystal loss. CN108467135A discloses a fully automated chemical crystallization circulating granulation fluidized bed water treatment system. Through the system combination and automatic control of a chemical crystallization circulating granulation fluidized bed unit, a reagent dosing unit, a pH adjustment unit, a seed crystal dosing unit, and a particle discharge unit, and by using CO2 instead of acid for effluent adjustment, it is economical and environmentally friendly.

[0006] However, the above-mentioned induced crystallization technology for treating high-salinity wastewater still has problems such as single function of reagent, waste of reagent due to incomplete use, need to adjust pH of effluent, more impurities in crystalline particles, and incomplete discharge of mature crystalline particles. SUMMARY

[0007] The present application provides a micro-interface induced crystallization separation device and method for metal ions in high-salinity wastewater.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0009] The present application provides a micro-interface induced crystallization separation device for metal ions in high-salinity wastewater, comprising a cylinder, wherein a fluid mixing zone, a circulating granulation zone, and a particle separation zone are sequentially arranged in the cylinder from bottom to top.

[0010] The fluid mixing zone comprises a water inlet pipe at the bottom end of the cylinder for high-salinity wastewater to enter and a seed crystal adding pipe arranged on the side wall of the cylinder; the high-salinity wastewater in the water inlet pipe is distributed at different speeds to the top end of the cylinder under the action of a gas-liquid distributor, enters the fluid mixing zone, mixes with the seed crystals entering the fluid mixing zone through the seed crystal adding pipe, and reacts in the fluid mixing zone under the assistance of alkali and acidic gas to obtain crystalline particles; the crystalline particles move upward into the circulating granulation zone to grow into mature crystalline particles; one side of the gas-liquid distributor is connected with a gas inlet pipe penetrating through the side wall of the cylinder for nitrogen to enter; the nitrogen helps the mature crystalline particles to move upward into the particle separation zone under the uniform distribution of the gas-liquid distributor; and the particle separation zone is provided with a three-phase separator for helping to separate gas, wastewater, and mature crystalline particles.

[0011] The micro-interface induced crystallization separation device for metal ions in high-salinity wastewater provided by the present application is provided with a fluid mixing zone, a circulating granulation zone, and a particle separation zone. The scientific arrangement of the three zones can realize stable removal of metal ions in high-salinity wastewater, circulating fluidized induced crystallization of seed crystal particles, and efficient desliming and separation and recovery of mature crystalline particles.

[0012] The lye, the acid gas and the high-salinity wastewater react in the fluid mixing zone, the metal ions to be crystallized and the non-metal ions or ion groups generated by the reaction are enriched on the surface of the crystal seeds, further react to generate low-solubility compounds, and obtain the crystalline particles. After the crystalline particles grow completely, the high-salinity wastewater in the water inlet pipe is switched to clean water, the lye and the acid gas stop entering, nitrogen is introduced into the fluid mixing zone, and the mature crystalline particles are sent to the particle separation zone by the nitrogen gathered in the lower part of the cylinder. The three-phase separator in the particle separation zone separates the nitrogen, the wastewater and the mature crystalline particles, and completes the treatment of the high-salinity wastewater.

[0013] The gas-liquid distributor can help the high-salinity wastewater to be distributed into the upper space of the gas-liquid distributor at different speeds. In addition, more crystalline particles can enter the circulating granulation zone, the flow direction of the crystal seeds in the circulating granulation is regulated, and the crystallization efficiency of the crystal seeds is improved.

[0014] In summary, the metal ion micro-interface induced crystallization separation device for high-salinity wastewater can realize efficient crystallization separation of metal ions in high-salinity wastewater.

[0015] Preferably, the fluid mixing zone further comprises a liquid inlet pipe for entering the lye and a feed pipe for entering the acid gas, the liquid inlet pipe and the feed pipe are oppositely arranged on the side wall of the cylinder, a gas-liquid distributor is arranged in the interior of the cylinder and located below the feed pipe, the seed adding pipe is arranged above the feed pipe, and a liquid vortex preventer is arranged on the water outlet of the water inlet pipe.

[0016] Preferably, the gas-liquid distributor comprises a low-speed zone close to the inner side wall of the cylinder, a high-speed zone wrapped in the inner side of the low-speed zone, and a gas-liquid distribution tray which helps the low-speed zone and the high-speed zone to be arranged in the interior of the cylinder.

[0017] The gas-liquid distribution tray can serve as a support plate for the crystalline particles.

[0018] Preferably, the high-speed zone alternately comprises a porous gas nozzle close to one side of the gas-liquid distribution tray near the top of the cylinder and a high-speed liquid distributor penetrating through the gas-liquid distribution tray, the high-speed liquid distributor comprises a lower recess close to one side of the gas-liquid distribution tray near the top of the cylinder, gas-liquid two-phase outlets are arranged on both sides of the lower recess, and the lower recess is connected with the gas-liquid distribution tray to form a channel for the high-salinity wastewater to enter.

[0019] The low-speed area is alternately provided with a porous gas nozzle on the side of the gas-liquid distribution tray close to the top of the cylinder and a low-speed liquid distributor penetrating the gas-liquid distribution tray, the low-speed liquid distributor comprises an upper convex part on the side of the gas-liquid distribution tray close to the top of the cylinder, both sides of the upper convex part are provided with gas-liquid two-phase outlets, and the lower end of the upper convex part is in communication with the gas-liquid distribution tray to form a channel for high-salinity wastewater.

[0020] The low-speed liquid distributor can adopt a convex annular gap design to increase the kinetic energy loss of water flow passing through, and the high-speed liquid distributor can adopt a concave annular gap design to reduce the kinetic energy loss of water flow passing through, and the effective combination of the two enables the water flow to be distributed at different speeds into the upper space of the gas-liquid distributor. In addition, through the differential arrangement of the low-speed liquid distributor and the high-speed liquid distributor, the outside of the cylinder cutting plane is the low-speed area and the inside is the high-speed area, which promotes more seed particles to enter the circulating granulation area and regulates the flow direction of the circulating seed particles.

[0021] The porous gas nozzle can uniformly distribute a gas flow into a plurality of dispersed gas flows with different angles, helping the high-speed nitrogen gas flow to be uniformly distributed into the interior of the cylinder.

[0022] Preferably, an aerator is arranged between the feed pipe and the interior space of the cylinder, the aerator comprises, from the outside of the cylinder to the inside in sequence, an air inlet and a gas distribution film that helps the acidic gas to be uniformly distributed into the interior of the cylinder, a bottom plate is arranged close to the gas distribution film between the gas distribution film and the air inlet, and a micropore outlet is arranged on the gas distribution film.

[0023] Preferably, the diameter of the micropore outlet is 80-100 μm.

[0024] The ultra-fine pore diameter helps to generate a large number of micro-nano bubbles. In the actual high-salinity wastewater treatment process, the micro-nano bubbles can provide a large gas-liquid contact area, and the rising speed of the bubbles is slow, which is good for the following of the seed particles. In addition, the ζ potential of the micro-nano bubble interface is high, which can adsorb organic matter in water, avoid the entrainment of impurities in the crystallization process, and make the purity of the crystalline particles higher.

[0025] Preferably, an atomizer is arranged between the liquid inlet pipe and the interior space of the cylinder, the atomizer comprises, from the outside of the cylinder to the inside in sequence, a liquid inlet and a liquid guide pipe, and a nozzle is arranged on the liquid guide pipe.

[0026] Preferably, the liquid guide pipe is a circular-arc-shaped liquid guide pipe, and the nozzle is a fan-shaped nozzle.

[0027] Preferably, the circulating granulation zone comprises a fluidization zone arranged inside the barrel and a circulating zone arranged between the fluidization zone and the barrel side wall, the fluidization zone comprises, from bottom to top of the barrel, a lower guide ring, a lower fluidization zone, an upper fluidization zone and an upper guide ring arranged in sequence, the diameter of the lower fluidization zone in the transverse direction is smaller than the diameter of the upper fluidization zone in the transverse direction.

[0028] Preferably, the lower guide ring is an open ring with the opening facing outward, and the upper guide ring is an open ring with the opening facing inward.

[0029] The lower guide ring is an open ring with the opening facing outward, forming a larger feeding area, which can control the upward moving crystalline particles to preferentially enter the lower fluidization zone; and the upper guide ring is an open ring with the opening facing inward, which reduces the probability of the crystalline particles falling back to the fluidization zone and increases the probability of falling back to the circulating zone, which is beneficial to the seed particles rising to the junction of the circulating granulation zone and the particle separation zone to accelerate the falling back to the circulating zone, thereby improving the circulating crystallization efficiency.

[0030] Preferably, the three-phase separator comprises a feeding barrel and a guide vane arranged in the feeding barrel to help separate nitrogen, wastewater and mature crystalline particles, a discharge pipe penetrating the barrel side wall is connected to the lower end of the feeding barrel, an electromagnetic valve is arranged on the discharge pipe, a water outlet penetrating the barrel side wall is arranged above the feeding barrel, and an exhaust pipe penetrating the barrel top and arranged opposite to the water inlet pipe is further arranged above the feeding barrel.

[0031] The application also provides a separation method of metal ion micro-interface induced crystallization in high-salinity wastewater, which uses the above-mentioned separation device of metal ion micro-interface induced crystallization in high-salinity wastewater to separate; comprising:

[0032] (1) The high-salinity wastewater is differentially distributed into the fluid mixing zone of the barrel from the water inlet pipe under the action of the gas-liquid distributor, the acid gas enters the fluid mixing zone of the barrel from the feeding pipe, the lye enters the fluid mixing zone of the barrel from the liquid inlet pipe, and the seed enters the fluid mixing zone of the barrel from the seed adding pipe, and the high-salinity wastewater, the acid gas and the lye react on the surface of the seed to form crystalline particles;

[0033] (2) The crystalline particles move upward into the circulating granulation zone, and continuously circulate and fluidize in the fluidization zone and the circulating zone, and grow into mature crystalline particles;

[0034] (3) The residual high-salinity wastewater in the barrel is discharged from the particle separation zone, then the high-salinity wastewater in the water inlet pipe is switched to clean water, the entry of the lye and the acid gas is stopped, nitrogen is introduced into the fluid mixing zone, the nitrogen is uniformly distributed under the action of the gas-liquid distributor, helps the mature crystalline particles to move upward into the particle separation zone, and separates the nitrogen, the wastewater and the mature crystalline particles under the action of the three-phase separator;

[0035] (4) repeating steps (1)-(3) to realize continuous crystallization separation treatment of metal ions in high-salt wastewater.

[0036] Preferably, in the step (1), the high-salt wastewater is a solution containing metal ions, and the metal ions include Ca 2+ , Mg 2 + , Fe 2+ , Mn 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Ag + , Cu 2+ , As 3+ , and Ba 2+ ; the acid gas is CO2, H2S or PH3, and the gas pressure is >0.8 Mpa; the lye is NaOH or KOH, and the pH is >12; the crystal seeds are one or more of limestone, dolomite, calcite, garnet, quartz sand, phosphorus iron ore, and pyrite ore, and the particle diameter of the crystal seeds is 0.1-0.5 mm.

[0037] Preferably, in the step (2), the accumulation height of the crystal seeds in the circulating granulation area is 0.15-0.2 of the total height of the circulating granulation area, the fluid upward velocity in the fluidization area is 40-60 m / h, the fluid upward velocity in the circulating area is 30-40 m / h, and the hydraulic retention time is 10-20 min; and the crystallization time of the mature crystalline particles is 3-5 days.

[0038] Preferably, in the step (3), the flow rate of the clean water is the same as the treatment amount of the high-salt wastewater, the flow rate of the nitrogen gas is 8-10 times the flow rate of the clean water, and the internal pressure of the cylinder is 0.2-0.3 Mpa; the separation time of the three-phase separator is 10-15 min, and the separation efficiency is >98%; the particle diameter of the mature crystalline particles is 1-3 mm, the water content is <0.5%, and the compressive strength is 40-60 Mpa.

[0039] Preferably, in the step (4), the separation efficiency of the metal ions in the high-salt wastewater is >95%.

[0040] Therefore, the present application has the following beneficial effects:

[0041] (1) The metal ion micro-interface induced crystallization separation device for high-salt wastewater provided by the present application helps the high-salt wastewater to enter the upper space of the gas-liquid distributor at different speeds with the help of the differential speed distribution gas-liquid distributor; at the same time, more crystalline particles are sent into the circulating granulation area, the flow direction of the crystal seeds in the circulating granulation is regulated, and the crystallization efficiency of the crystal seeds is improved.

[0042] (2) The present application is a fluidized zone with a wide upper part and a narrow lower part in the circulating granulation zone, by increasing the flow passage cross-sectional area of the upper fluidized zone, providing more sufficient reaction space for the crystalline particles, and weakening the drag force of the fluid on the seed particles, prolonging the residence time of the crystalline particles in the upper fluidized zone.

[0043] (3) The present application is a three-phase separation device arranged at the upper end of the metal ion micro-interface induced crystallization separation device in high-salinity wastewater, which realizes the separation of mature crystalline particles and sludge particles by means of the different accelerations generated by the cyclonic shear field and the self-rotating motion of mature crystalline particles and sludge particles attached to the surface of the mature crystalline particles, and the sludge particles are detached into the water phase and discharged with the wastewater, while the high-purity mature crystalline particles are discharged from the discharge pipe.

[0044] (4) The method provided by the present application adopts the combined mode of alkaline solution + acidic gas to generate inorganic anions to react with metal ions in high-salinity wastewater, which reduces the amount of alkaline solution and the cost of reagent use, and realizes the resource utilization of acidic gas waste in industrial production.

[0045] (5) The method provided by the present application does not need to adjust the pH of the effluent. By controlling the flow of acidic gas, it can not only meet the needs of inorganic anions in the crystallization process, but also neutralize the excess alkaline reagent, so as to realize the stability of the effluent pH without introducing additional neutralizing reagents for adjustment.

[0046] (6) The mature crystalline particles separated by the present application have high purity. The separation device is provided with an aerator, the acidic gas becomes micro-nano bubbles through the aerator, which can provide a large gas-liquid contact area, and the rising speed of the bubbles is slow, which is good for the following of the seed particles. In addition, the ζ potential of the micro-nano bubble interface is high, which can adsorb organic matter in water, avoid the entrainment of impurities in the crystallization process, and make the purity of the crystalline particles higher. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 It is a schematic diagram of the overall structure of the metal ion micro-interface induced crystallization separation device in high-salinity wastewater;

[0048] Figure 2 It is an enlarged schematic diagram of the structure of the gas-liquid distributor;

[0049] Figure 3 It is a schematic diagram of the arrangement of each component of the gas-liquid distributor;

[0050] Figure 4 It is an enlarged schematic diagram of the structure of the aerator;

[0051] Figure 5 It is an enlarged schematic diagram of the structure of the atomizer;

[0052] Figure 6This is a magnified schematic diagram of the structure of the circulating granulation zone;

[0053] Figure 7 This is an enlarged schematic diagram of the three-phase separator.

[0054] Figure 8 A schematic diagram illustrating the working principle of a three-phase separator;

[0055] The codes in the diagram are as follows: cylinder 100, fluid mixing zone 110, water inlet pipe 111, seed crystal adding pipe 112, liquid inlet pipe 113, feed pipe 114, gas-liquid distributor 115, low-speed zone 1151, low-speed liquid distributor 1151a, upper convex part 1151b, high-speed zone 1152, high-speed liquid distributor 1152a, lower concave part 1152b, gas-liquid distribution tray 1153, porous gas nozzle 1154, gas-liquid two-phase outlet 1155, air inlet pipe 116, liquid anti-vortex device 117, aerator 118, air inlet 1181. Chassis 1182, air distribution film 1183, microporous outlet 1183a, atomizer 119, liquid inlet 1191, liquid guide pipe 1192, nozzle 1193, circulating granulation zone 120, fluidization zone 121, lower guide ring 1211, lower fluidization zone 1212, upper fluidization zone 1213, upper guide ring 1214, circulation zone 122, particle separation zone 130, three-phase separator 131, feed cylinder 1311, guide vane 1312, discharge pipe 1313, solenoid valve 1313a, water outlet 1314, exhaust pipe 1315. Detailed Implementation

[0056] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0057] Example 1

[0058] observe Figures 1-7 As can be seen, this embodiment provides a metal ion micro-interface induced crystallization separation device for high-salt wastewater, including a cylinder 100. Inside the cylinder 100, from bottom to top, are arranged a fluid mixing zone 110, a circulating granulation zone 120, and a particle separation zone 130. The scientific arrangement of these three zones enables the stable removal of metal ions from high-salt wastewater, the circulating fluidized bed induced crystallization of seed particles, and the efficient desludge removal and separation recovery of mature crystal particles.

[0059] observe Figure 1It can be seen that the fluid mixing zone 110 includes a water inlet pipe 111 arranged at the bottom end of the cylinder body 100 for high-salt wastewater to enter, and a liquid anti-vortex device 117 is arranged at the water outlet 1314 of the water inlet pipe 111. From bottom to top of the cylinder body 100, a feed pipe 114, a liquid inlet pipe 113 and a seed crystal pipe 112 are arranged in sequence. The alkali solution enters from the liquid inlet pipe 113 arranged on the right side of the cylinder body 100, the acidic gas enters from the feed pipe 114 arranged on the left side of the cylinder body 100, and the high-salt wastewater enters from the bottom of the cylinder body 100. The three react in the fluid mixing zone 110, the metal ions and the non-metal ions or ion groups generated by the reaction are enriched on the surface of the seed crystal, and further reaction generates a compound with low solubility to obtain crystalline particles.

[0060] In combination Figure 1 And Figure 2 、 Figure 3 It can be seen that the cylinder body 100 is internally provided with a gas-liquid distributor 115, and the gas-liquid distributor 115 is located below the feed pipe 114. The gas-liquid distributor 115 is communicated with a gas inlet pipe 116 penetrating through one side wall of the cylinder body 100 for nitrogen to enter. The gas-liquid distributor 115 includes a low-speed area 1151 close to the inner side wall of the cylinder body 100, a high-speed area 1152 wrapped inside the low-speed area 1151, and a gas-liquid distribution tower plate 1153 helping the low-speed area 1151 and the high-speed area 1152 to be arranged in the cylinder body 100. The gas-liquid distribution tower plate 1153 can serve as a support plate for the crystalline particles, and the gas-liquid distribution tower plate 1153 is penetrated by the gas inlet pipe 116. The high-speed nitrogen gas enters the gas-liquid distribution tower plate 1153 from the gas inlet pipe 116, is buffered in the gas-liquid distribution tower plate 1153, and then enters the inside of the cylinder body 100 from the multiple porous gas nozzles 1193 1154 on the side of the top of the cylinder body 100. The multiple porous gas nozzles 1193 1154 can uniformly distribute a gas flow into multiple angle dispersed gas flows, which can be used for uniform distribution of high-speed nitrogen gas flow.

[0061] The high-speed area 1152 is alternately provided with multiple porous gas nozzles 1193 1154 on the side of the top of the cylinder body 100 close to the gas-liquid distribution tower plate 1153 and multiple high-speed liquid distributors 1152a penetrating through the gas-liquid distribution tower plate 1153. Each high-speed liquid distributor 1152a includes a lower recess 1152b located on the side of the top of the cylinder body 100 close to the gas-liquid distribution tower plate 1153, multiple gas-liquid two-phase outlets 1155 are arranged on both sides of the lower recess 1152b, and the lower recess 1152b and the gas-liquid distribution tower plate 1153 form a channel for high-salt wastewater to enter.

[0062] The low-speed zone 1151 is alternately provided with a plurality of porous gas nozzles 1193 1154 on the side of the gas-liquid distribution tray 1153 close to the top of the cylinder 100 and a plurality of low-speed liquid distributors 1151a penetrating the gas-liquid distribution tray 1153. Each low-speed liquid distributor 1151a includes an upper protrusion 1151b on the side of the gas-liquid distribution tray 1153 close to the top of the cylinder 100, and a plurality of gas-liquid two-phase outlets 1155 are arranged on both sides of the upper protrusion 1151b, and the upper protrusion 1151b and the gas-liquid distribution tray 1153 form a channel for high-salinity wastewater to enter. The low-speed liquid distributor 1151a adopts a protruding annular gap design, which increases the kinetic energy loss of the water flow passing through; while the high-speed liquid distributor 1152a adopts a recessed annular gap design, which reduces the kinetic energy loss of the water flow passing through, and the effective combination of the two enables the water flow to be distributed at different speeds into the upper space of the gas-liquid distributor 115. In addition, through the differential arrangement of the low-speed liquid distributor 1151a and the high-speed liquid distributor 1152a, the outside of the tangent plane of the cylinder 100 is the low-speed zone 1151 and the inside is the high-speed zone 1152, which promotes more seed particles to enter the circulating granulation zone 120 and controls the flow direction of the circulating granulation seed particles.

[0063] In combination Figure 1 and Figure 6 It can be seen that the circulating granulation zone 120 includes a fluidization zone 121 arranged inside the cylinder 100 and a circulating zone 122 arranged between the fluidization zone 121 and the side wall of the cylinder 100. The fluidization zone 121 includes a lower flow guide ring 1211, a lower fluidization zone 1212, an upper fluidization zone 1213, and an upper flow guide ring 1214 arranged in the direction from the bottom to the top of the cylinder 100 in sequence, and the diameter of the lower fluidization zone 1212 in the transverse direction is smaller than that of the upper fluidization zone 1213. The diameter of the upper fluidization zone 1213 is larger, which can help to increase the cross-sectional area of the flow passage and provide more sufficient reaction space for the crystalline particles; at the same time, it can weaken the drag force of the fluid on the seed particles and prolong the residence time of the crystalline particles in the upper fluidization zone 1213. The lower flow guide ring 1211 is an open ring with the opening facing outward, forming a larger feeding area, which can control the upward moving crystalline particles to preferentially enter the lower fluidization zone 1212; while the upper flow guide ring 1214 is an open ring with the opening facing inward, which reduces the probability of crystalline particles falling back to the fluidization zone 121 and increases the probability of falling back to the circulating zone 122, which is beneficial to the seed particles rising to the junction of the circulating granulation zone 120 and the particle separation zone 130 to accelerate the falling back to the circulating zone 122, thereby improving the circulating crystallization efficiency.

[0064] After the crystalline particles grow completely, the high-salinity wastewater in the water inlet pipe 111 is switched to clean water, and the alkali and acidic gas are stopped, and nitrogen is introduced into the fluid mixing zone 110. The nitrogen gas collected in the lower part of the cylinder 100 sends the mature crystalline particles to the particle separation zone 130. As Figure 7As shown, the three-phase separator 131 in the particle separation zone 130 separates nitrogen, wastewater, and mature crystalline particles. The three-phase separator 131 includes a feed cylinder 1311 and guide vanes 1312 disposed within the feed cylinder 1311 to aid in the separation of nitrogen, wastewater, and mature crystalline particles. A discharge pipe 1313, penetrating the side wall of the cylinder 100, is connected to the lower end of the feed cylinder 1311. A solenoid valve 1313a is installed on the discharge pipe 1313. An outlet 1314, penetrating the side wall of the cylinder 100, is located above the feed cylinder 1311. An exhaust pipe 1315, penetrating the top of the cylinder 100 and positioned opposite the inlet pipe 111, is also located above the feed cylinder 1311. The guide vanes 1312 are arranged in a ring around the inside of the feed cylinder 1311 to ensure that the generated swirling shear field meets the separation requirements.

[0065] like Figure 8 As shown, after the crystalline particles with attached sludge particles enter the feed cylinder 1311 along with the multiphase mixture, the fluid is twisted and generates a swirling shear field when passing through the guide vane 1312. The mature crystalline particles and sludge particles generate revolution and rotation in the flow field. The revolution can separate the mature crystalline particles and sludge particles in the multiphase mixture, and the rotation can help the mature crystalline particles and the sludge particles attached to the surface of the mature crystalline particles to generate different accelerations. Under the action of oscillating centrifugal force, the sludge particles are desorbed from the surface of the mature crystalline particles and removed. The desorbed sludge particles enter the wastewater and are discharged through the outlet 1314. The mature crystalline particles, due to their higher weight, are discharged from the cylinder 100 through the discharge pipe 1313 at the bottom of the feed cylinder 1311. Nitrogen gas leaves the cylinder 100 from the exhaust pipe 1315 at the top of the cylinder 100.

[0066] Example 2

[0067] This embodiment optimizes the solution by adding an aerator 118 and an atomizer 119 to the solution based on embodiment 1. The atomizer 119 consists of 3 sets of fan-shaped nozzles 119 distributed in an arc shape, and the aerator 118 is a diaphragm-type microporous aeration disc.

[0068] like Figure 4 As shown, an aerator 118 is provided between the feed pipe 114 and the internal space of the cylinder 100. The aerator 118 includes an air inlet 1181 arranged sequentially from the outside to the inside of the cylinder 100 and an air distribution membrane 1183 that helps acidic gas to enter the interior of the cylinder 100 evenly. A base plate 1182 is provided between the air distribution membrane 1183 and the air inlet 1181, which is in close contact with the air distribution membrane 1183. The air distribution membrane 1183 has a microporous outlet 1183a. The air distribution membrane 1183 can be replaced when necessary to ensure aeration, greatly reducing the cost of subsequent equipment maintenance. The diameter of the microporous outlet 1183a is 90μm, and the ultra-fine pore size helps to generate a large number of micro-nano bubbles.

[0069] like Figure 5As shown, the liquid inlet pipe 113 is provided with an atomizer 119 between the inside space of the cylinder 100, the atomizer 119 including a liquid inlet 1191 and a circular-arc liquid guide pipe 1192 arranged in sequence from the outside to the inside of the cylinder 100, and the circular-arc liquid guide pipe 1192 is provided with a fan-shaped nozzle 1193. The circular-arc liquid guide pipe 1192 makes the lye spread along the circumference and uniformly spray from the fan-shaped nozzle 1193 in a tangential direction, thereby realizing the effect of three-dimensional atomization of the lye into the cylinder 100.

[0070] The use method of the separation device in Example 2 is as follows:

[0071] (1) When the crystal seeds in the cylinder 100 are in a small particle size and irregular state, the high-salt wastewater enters the water inlet pipe 111, and after the liquid vortex preventer 117, the speed is reduced, and is dispersed to pass through the gas-liquid distributor 115 into the fluid mixing area 110. At this time, the acidic gas enters the feed pipe 114, and under the action of the aerator 118, it becomes micro-nano bubbles into the fluid mixing area 110; the lye enters the liquid inlet pipe 113, and under the action of the atomizer 119, it becomes dispersed small droplets into the fluid mixing area 110. After the high-salt wastewater, the acidic gas, and the lye contact in the fluid mixing area 110, the crystal seeds induce the metal ions and the reaction-generated non-metal ions or ion groups to be crystallized on the surface of the crystal seeds, and further react to generate low-solubility compounds to obtain crystalline particles. Among them, the acidic gas is CO2, H2S or PH3, the gas pressure is >0.8 Mpa; the lye is NaOH or KOH, the pH is >12; the high-salt wastewater is a solution containing metal ions, and the metal ions are Ca 2+ , Mg 2+ , Fe 2+ , Mn 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Ag + , Cu 2+ , As 3+ , and Ba 2+ .

[0072] (2) The crystalline particles move upward and pass through the lower fluidized area 1212, the upper fluidized area 1213, and the circulation area 122 in sequence, and continuously circulate and fluidize in the fluidized area 121 and the circulation area 122, and grow into mature crystalline particles.

[0073] Among them, the possible reaction process of the acidic bubbles and the alkaline droplets is as follows:

[0074]

[0075] H2S+2OH - →S 2- +2H2O

[0076]

[0077] The crystallization reaction process on the surface of the seed crystal is as follows:

[0078]

[0079] Cu 2+ / As 3+ +S 2- → sulfide crystal

[0080]

[0081] (3) When a large number of matured crystalline particles appear, the electromagnetic valve 1313a is opened, and the residual high-salinity wastewater in the cylinder 100 is discharged from the water outlet 1314. The high-salinity wastewater in the water inlet pipe 111 is switched to clean water, and the entering of the lye and the acidic gas is stopped, and nitrogen is introduced into the gas inlet pipe 116. The high-speed flowing gas-liquid two-phase is uniformly dispersed in the water phase channel and the gas phase channel of the gas-liquid distributor 115, and flows into the fluid mixing area 110 to contact each other in the cylinder 100. The turbulent motion of the mixed fluid will generate strong shear stress, so that the irregular sludge large particles deposited at the bottom are dispersed into spherical sludge small particles. Under the drag force of the mixed fluid, the matured crystalline particles and the sludge small particles are entrained to pass through the circulating granulation area 120 into the three-phase separator 131 in the particle separation area 130, and the matured crystalline particles are separated and recovered under the self-rotation coupling centrifugal force of the cyclone field. Finally, the electromagnetic valve 1313a is opened, the matured crystalline particles are discharged from the discharge pipe 1313, the water phase containing sludge particles is discharged from the water outlet pipe, and the nitrogen is discharged from the exhaust pipe 1315.

[0082] (4) Steps (1)-(3) are repeated to realize continuous crystallization separation treatment of metal ions in high-salinity wastewater.

[0083] Application Example 1

[0084] In a coal gasification process with a normal processing capacity of 2500 tons of coal / hour, the high-salinity wastewater metal ion micro-interface induced crystallization separation device provided in Example 2 is used, and the coal gasification ash water containing high-concentration calcium and magnesium ions is treated as high-salinity wastewater according to the above-mentioned use method. The specific operation process and effect are described as follows:

[0085] 1. Wastewater properties and related parameters

[0086] The ash water properties and parameters of the ash water of a certain plant under the liquid phase operating state are as shown in Table 1

[0087] Table 1 Properties and parameters of the ash water of a certain plant before treatment

[0088]

[0089] Note: Hardness and alkalinity are expressed as CaCO3.

[0090] 2. Micro-interface induced crystallization separation device

[0091] The barrel diameter of the micro-interface induced crystallization separation device for metal ions in high-salinity wastewater is 0.3 meters, the overall height is 2.8 meters, and the single processing capacity is 1 m 3 / h. A three-phase separator is installed at the top of the separation device for efficient desliming and separation and recovery of mature crystalline particles.

[0092] 3. Implementation process

[0093] ① Fluid mixing

[0094] According to the above "Example 2, method of using the separation device" section, specifically: add limestone seed with a particle size of 40-80 mesh into the seed addition tube, with a stacking height of 0.3-0.4 meters, pass NaOH solution (pH > 12) into the liquid inlet pipe, pass CO2 gas (pressure > 0.8 MPa) into the feed pipe, and pass coal gasification ash water with the composition shown in Table 1 into the water inlet pipe at a flow rate of 1 m 3 / h, the fluid rising speed in the fluidization zone is 40 m / h, and the fluid rising speed in the circulation zone is 30 m / h, with a hydraulic retention time of 10 minutes.

[0095] ② Circulating granulation

[0096] The micro-interface induced crystallization separation device for metal ions in high-salinity wastewater is continuously operated for 3-5 days according to the (2) described in the "Example 2, method of using the separation device" section, and the residual coal gasification ash water with the composition shown in Table 1 in the barrel is discharged from the water outlet. Switch the coal gasification ash water in the water inlet pipe to clean water (flow rate 1 m 3 / h), and stop the entry of NaOH solution and CO2 gas, and pass nitrogen gas (flow rate 8 m 3 / h) into the gas inlet pipe. The operation time is 10-15 minutes, the internal pressure of the barrel is 0.2 MPa, the separation efficiency of mature crystalline particles is > 98%, and the particle size range is 1-3 mm.

[0097] 4. Implementation effect

[0098] The properties and parameters of the treated coal gasification grey water are shown in Table 2. It can be observed that the hardness and turbidity are obviously reduced, the reduction rate of total hardness and turbidity can reach more than 85%, the removal rate of COD is >55%, the pH value and alkalinity are slightly increased. In addition, the suspended solids content of the separated coal gasification grey water is increased; the reason is that the micro-nano bubbles make the colloidal particles in the grey water aggregate and grow into suspended particles, a small part of which sinks with the crystallized silt, and most of which rises to the outlet with the grey water, so a three-phase separator is arranged at the last end of the crystallization separation device, which can remove the suspended solids of the softened effluent on the one hand, and purify the silt-containing wastewater after the mature crystalline particles are desilted on the other hand.

[0099] Table 2 Properties and parameters of the treated coal gasification grey water of a certain plant

[0100]

Claims

1. A device for separating metal ions from high-salinity wastewater by micro-interface induced crystallization, characterized in that, The device comprises a cylinder, and a fluid mixing area, a circulating granulation area and a particle separation area are sequentially arranged in the cylinder from bottom to top. The fluid mixing area comprises a water inlet pipe for high-salinity wastewater at the bottom end of the cylinder and a seed crystal adding pipe on the side wall of the cylinder; the high-salinity wastewater in the water inlet pipe is distributed to the top end of the cylinder under the action of a gas-liquid distributor and enters the fluid mixing area, mixes with the seed crystals entering the fluid mixing area through the seed crystal adding pipe, and reacts in the fluid mixing area under the assistance of alkali and acid gas to obtain crystalline particles; the crystalline particles move upward into the circulating granulation area to grow into mature crystalline particles; one side of the gas-liquid distributor is connected with a gas inlet pipe penetrating through the side wall of the cylinder for nitrogen gas to enter; the nitrogen gas helps the mature crystalline particles move upward into the particle separation area under the uniform distribution of the gas-liquid distributor; and the particle separation area is provided with a three-phase separator for separating gas, wastewater and mature crystalline particles.

2. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 1, wherein, The fluid mixing area further comprises a liquid inlet pipe for entering alkali and a feed pipe for entering acid gas; the liquid inlet pipe and the feed pipe are oppositely arranged on the side wall of the cylinder; a gas-liquid distributor is arranged inside the cylinder and located below the feed pipe; the seed crystal adding pipe is arranged above the feed pipe; and a liquid anti-vortex device is arranged on the water outlet of the water inlet pipe.

3. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 1 or 2, characterized in that, The gas-liquid distributor comprises a low-speed area close to the inner side wall of the cylinder, a high-speed area wrapped inside the low-speed area, and a gas-liquid distribution tray plate for helping the low-speed area and the high-speed area to be arranged around the inside of the cylinder.

4. The device for micro-interface induced crystallization separation of metal ions in high-salinity wastewater of claim 3, wherein, The high-speed area is alternately provided with a porous gas nozzle on one side of the gas-liquid distribution tray plate close to the top of the cylinder and a high-speed liquid distributor penetrating through the gas-liquid distribution tray plate; the high-speed liquid distributor comprises a lower recess on one side of the gas-liquid distribution tray plate close to the top of the cylinder; gas-liquid two-phase outlets are arranged on both sides of the lower recess; and the lower end of the lower recess is connected with the gas-liquid distribution tray plate to form a channel for high-salinity wastewater to enter. The low-speed area is alternately provided with a porous gas nozzle on one side of the gas-liquid distribution tray plate close to the top of the cylinder and a low-speed liquid distributor penetrating through the gas-liquid distribution tray plate; the low-speed liquid distributor comprises an upper protrusion on one side of the gas-liquid distribution tray plate close to the top of the cylinder; gas-liquid two-phase outlets are arranged on both sides of the upper protrusion; and the lower end of the upper protrusion is connected with the gas-liquid distribution tray plate to form a channel for high-salinity wastewater to enter.

5. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 2, wherein, An aerator is arranged between the feed pipe and the internal space of the cylinder; the aerator comprises an air inlet and a gas distribution membrane in sequence from the outside to the inside of the cylinder, the gas distribution membrane helps the acid gas to uniformly enter the internal space of the cylinder; a bottom plate close to the gas distribution membrane is arranged between the gas distribution membrane and the air inlet; and a micropore outlet is arranged on the gas distribution membrane.

6. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 2, wherein, An atomizer is arranged between the liquid inlet pipe and the internal space of the cylinder; the atomizer comprises a liquid inlet and a liquid guide pipe in sequence from the outside to the inside of the cylinder; and a nozzle is arranged on the liquid guide pipe.

7. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 1, wherein, The circulating granulation zone comprises a fluidization zone arranged inside the cylinder and a circulating zone arranged between the fluidization zone and the side wall of the cylinder, the fluidization zone comprises, from bottom to top of the cylinder, a lower flow guide ring, a lower fluidization zone, an upper fluidization zone and an upper flow guide ring, the diameter of the lower fluidization zone in the transverse direction is smaller than the diameter of the upper fluidization zone in the transverse direction.

8. The device for metal ion micro-interface induced crystallization separation in high-salinity wastewater of claim 1, wherein, The three-phase separator comprises a feeding cylinder and a flow guide blade arranged in the feeding cylinder to help separate nitrogen, waste water and mature crystalline particles, a discharge pipe penetrating the side wall of the cylinder is connected to the lower end of the feeding cylinder, an electromagnetic valve is arranged on the discharge pipe, a water outlet penetrating the side wall of the cylinder is arranged above the feeding cylinder, and an exhaust pipe penetrating the top of the cylinder and arranged opposite to the water inlet pipe is further arranged above the feeding cylinder.

9. A separation method of metal ions in high-salinity wastewater by micro-interface induced crystallization, characterized in that, The separation is performed by using the high-salinity wastewater metal ion micro-interface induced crystallization separation device according to any one of claims 1-8; comprising: (1) the high-salinity wastewater is differentially distributed into the fluid mixing zone of the cylinder from the water inlet pipe under the action of the gas-liquid distributor, the acid gas enters the fluid mixing zone of the cylinder from the feeding pipe, the lye enters the fluid mixing zone of the cylinder from the liquid inlet pipe, and the crystal seed enters the fluid mixing zone of the cylinder from the crystal seed adding pipe, and the high-salinity wastewater, the acid gas and the lye react on the surface of the crystal seed to form crystalline particles; (2) the crystalline particles move upward into the circulating granulation zone, and continuously circulate and fluidize in the fluidization zone and the circulating zone to grow into mature crystalline particles; (3) the residual high-salinity wastewater in the cylinder is discharged from the particle separation zone, then the high-salinity wastewater in the water inlet pipe is switched to clean water, the entry of the lye and the acid gas is stopped, nitrogen is introduced into the fluid mixing zone, the nitrogen is uniformly distributed under the action of the gas-liquid distributor to help the mature crystalline particles move upward into the particle separation zone, and the nitrogen, the wastewater and the mature crystalline particles are separated by the three-phase separator; (4) steps (1)-(3) are repeated to realize continuous crystallization separation treatment of the metal ions in the high-salinity wastewater.

10. The high-salinity wastewater metal ion micro-interface induced crystallization separation method according to claim 9, wherein In the step (1), the high-salinity wastewater is a solution containing metal ions, including Ca 2+ , Mg 2+ , Fe 2+ , Mn 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Ag + , Cu 2+ , As 3+ , and Ba 2+ ; the acid gas is CO2, H2S, or PH3, with a gas pressure of >0.8 Mpa; the lye is NaOH or KOH, with a pH of >12; the seed crystal is one or more of limestone, dolomite, calcite, garnet, quartz sand, phosphorous iron ore, and pyrite ore, with a particle diameter of 0.1-0.5 mm; in the step (2), the accumulation height of the crystal seed in the circulating granulation zone is 0.15-0.2 of the total height of the circulating granulation zone, the fluid upward velocity in the fluidization zone is 40-60 m / h, the fluid upward velocity in the circulating zone is 30-40 m / h, and the hydraulic retention time is 10-20 min; the crystallization time of the mature crystalline particles is 3-5 days; in the step (3), the flow rate of the clean water is the same as the treatment capacity of the high-salinity wastewater, the flow rate of the nitrogen is 8-10 times the flow rate of the clean water, the internal pressure of the cylinder is 0.2-0.3 Mpa; the separation time of the three-phase separator is 10-15 min, the separation efficiency is >98%, the particle size of the mature crystalline particles is 1-3 mm, the water content is <0.5%, and the compressive strength is 40-60 Mpa; in the step (4), the separation efficiency of the metal ions in the high-salinity wastewater is >95%.

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