Micro-interface induced crystallization separation device and separation method for metal ions in high-salinity wastewater

Abstract

The invention relates to the technical field of high-salinity wastewater, in particular to a micro-interface induced crystallization separation device and method for metal ions in high-salinity wastewater. The invention provides a micro-interface induced crystallization separation device for metal ions in high-salinity wastewater, which 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. According to the micro-interface induced crystallization separation device for the metal ions in the high-salinity wastewater, the high-salinity wastewater is helped to enter the upper space of the gas-liquid distributor in a differential distribution manner by virtue of the gas-liquid distributor in differential distribution; and meanwhile, more crystallized particles are fed into the circulating granulation area, so that the seed crystal flowing direction of circulating granulation is regulated and controlled, and the crystallization efficiency of the seed crystal is improved. A fluidization area with a wide upper part and a narrow lower part is designed in a circulating granulation area, a more sufficient reaction space is provided for crystal particles by increasing the sectional area of a runner in the fluidization area at the upper part, the drag force effect of fluid on seed crystal particles is weakened, and the retention time of the crystal particles in the fluidization area at the upper part is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of high-salt wastewater, and in particular to a metal ion microinterface induced crystallization separation device and a separation method in high-salt wastewater. Background Art

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

[0003] High-salinity wastewater is generally pre-treated to remove suspended solids, oils and organic matter, and then metal ions are separated by concentration desalination + crystallization solidification. Common crystallization solidification technologies include evaporation crystallization, cooling crystallization, membrane distillation crystallization, nanofiltration fractionation crystallization, etc. Among them, evaporation crystallization technology is simple to operate, but the equipment structure is complex and the energy consumption is high; cooling crystallization technology has high production efficiency, but the operation and maintenance costs are high, and the material requirements are strict; membrane distillation crystallization technology has simple equipment and easy operation, but the membrane material cost is high and the performance is not stable enough; nanofiltration fractionation crystallization technology can perform selective crystallization, and the product purity is high, but the membrane is easy to clog and the maintenance cost is high.

[0004] Faced with 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 such as simple operation, low cost, high efficiency, no secondary pollution, and easy recycling of crystallized products.

[0005] For example, CN105502692A discloses a chemical crystallization circulating granulation fluidized bed water treatment device. It is provided with a water distribution area, a drug distribution area, a granulation area, and a clean water area. By improving the drug addition layer and adding an inner cylinder and an outer cylinder to form a double-layer structure, the seed particles can be circulated and fluidized, the crystallization efficiency is improved, and the particles grown after crystallization are discharged from the bottom. CN111498967A discloses a crystallization fluidized bed for wastewater defluorination, dephosphorization, and dehardness treatment. Under the condition that the overall flow rate of the bed layer remains unchanged, the use of an improved differential water distributor can make the crystal particles form in a dynamic process of sinking in a low flow rate area - being sucked to a high flow rate area and floating up - and then migrating to a low flow rate area to sink, and further grow, thereby improving the crystallization efficiency. CN106044997B discloses a Fe-containing 3+ Treatment method of heavy metal wastewater. Use reducing agent to reduce Fe 3+ Reduction to Fe 2+ , and then Fe is removed and recovered by induced crystallization 2+ and other heavy metal ions. CN115583706A discloses a chemical crystallization circulating granulation fluidized bed water treatment device. A two-stage annular dosing pipe is set to realize the gradient feeding of sodium hydroxide and sodium carbonate, and a pressure detection system is set to realize the automatic discharge of crystal particles and the addition of seed particles. At the same time, an external transmission pipe is added to effectively alleviate the situation of water flow stagnation and scaling when the equipment is stopped or the water source is insufficient. CN116177762A discloses an internal pressure self-circulating heterogeneous crystallization fluidized bed water treatment device. The inside of the cylinder is divided into a water 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 partition is connected to the reflux partition through a guide pipe, and the bottom of the reflux partition is connected to the bottom of the reaction partition through a reflux pipe, so as to realize the internal circulation fluidization of the seed crystal and improve the crystallization efficiency. CN116924533A discloses a nuclear crystal granulation method for accurate salt separation of high-valent metal ions in high-salinity wastewater. By using N-stage series-connected nuclear crystal granulation equipment, N kinds of high-valent metal ions are crystallized on N kinds of characteristic crystal seeds in sequence, thereby realizing the precise separation and recovery of N kinds of metal ions. CN116947185A discloses a nuclear crystal granulation water treatment device and a nuclear crystal granulation water treatment system. Wastewater enters from the bottom of a horizontally placed reaction cylinder, reacts in reverse contact with the reagent entering from the top, and crystallizes on the crystal seed particles filled in the reactor. According to the water purification requirements, a reflux pipe is selectively connected between the drain port and the water inlet, and a crystal seed filtering and intercepting structure is set at the drain port to avoid crystal seed loss. CN108467135A discloses a fully automatic chemical crystallization circulating granulation fluidized bed water treatment system. Through the system combination and automatic control of the chemical crystallization circulating granulation fluidized bed unit, the reagent dosing unit, the pH adjustment unit, the crystal seed dosing unit and the particle discharge unit, the effluent is regulated by CO2 instead of acid, which 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 the reagent, incomplete use of the reagent causing waste, pH adjustment of the effluent water quality, large amount of crystal particle impurities, and incomplete discharge of mature crystals. Therefore, the art urgently needs to develop an economical, efficient, environmentally friendly, and highly applicable induced crystallization separation method and device. Summary of the invention

[0007] The invention provides a device and method for separating metal ions in high-salinity wastewater by micro-interface induced crystallization. The device can separate metal ions in high-salinity wastewater at low cost and high efficiency.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] The present invention provides a micro-interface induced crystallization separation device for metal ions in high-salt 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 includes an inlet pipe arranged at the bottom of the cylinder for high-salt wastewater to enter and a seeding pipe arranged on the side wall of the cylinder; the high-salt wastewater in the inlet pipe is differentially distributed toward the top of the cylinder under the action of the gas-liquid distributor and enters the fluid mixing zone, and is mixed with the seeds entering the fluid mixing zone through the seeding pipe, and reacts in the fluid mixing zone with the assistance of alkaline solution and acidic gas to obtain crystalline particles; the crystalline particles move upward into the circulating granulation zone to grow into mature crystalline particles, and one side of the gas-liquid distributor is connected to an inlet pipe for nitrogen to enter and penetrate one side wall of the cylinder. 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 that helps separate gas, wastewater and mature crystalline particles.

[0011] The metal ion micro-interface induced crystallization separation device in high-salinity wastewater provided by the present invention 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 the stable removal of metal ions in high-salinity wastewater, the circulating fluidization induced crystallization of seed particles, and the efficient desludging and separation recovery of mature crystal particles.

[0012] Alkali, acidic gas, and high-salt wastewater react in the fluid mixing zone. The crystal seeds induce the metal ions to be crystallized and the non-metallic ions or ion groups generated by the reaction to be enriched on the surface of the crystal seeds, and further react to generate compounds with low solubility to obtain crystalline particles. After the crystal particles are fully grown, the high-salt wastewater in the water inlet pipe is switched to clean water, and the entry of alkali and acidic gas is stopped. Nitrogen is introduced into the fluid mixing zone, and the nitrogen collected in the lower part of the cylinder sends the mature crystalline particles to the particle separation zone. The three-phase separator in the particle separation zone separates the nitrogen, wastewater, and mature crystalline particles to complete the treatment of high-salt wastewater.

[0013] Among them, the gas-liquid distributor can not only help high-salinity wastewater enter the upper space of the gas-liquid distributor at a differential speed, but also help more crystal particles enter the circulating granulation area, regulate the flow direction of the crystal seeds of the circulating granulation, and improve the crystallization efficiency of the crystal seeds.

[0014] In summary, the microinterface induced crystallization separation device for metal ions in high-salt wastewater can realize efficient crystallization separation of metal ions in high-salt wastewater.

[0015] Preferably, the fluid mixing zone also includes a liquid inlet pipe for entering the alkali solution and a feed pipe for entering the acidic gas, the liquid inlet pipe and the feed pipe are relatively arranged on the side wall of the cylinder, a gas-liquid distributor is arranged inside the cylinder and the gas-liquid distributor is located below the feed pipe, the seeding 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 includes a low-speed zone close to the inner wall of the cylinder, a high-speed zone wrapped inside the low-speed zone, and a gas-liquid distribution tower plate that helps the low-speed zone and the high-speed zone to be arranged in a circle inside the cylinder.

[0017] The gas-liquid distribution tower plate can be used as a support plate for crystallized particles.

[0018] Preferably, the high-speed zone is alternately provided with a porous gas nozzle on the side of the gas-liquid distribution plate close to the top of the cylinder and a high-speed liquid distributor penetrating the gas-liquid distribution plate, the high-speed liquid distributor comprises a concave portion located on the side of the gas-liquid distribution plate close to the top of the cylinder, gas-liquid two-phase outlets are arranged on both sides of the concave portion, and the lower end of the concave portion is connected with the gas-liquid distribution plate to form a channel for high-salt wastewater to enter;

[0019] The low-speed zone is alternately provided with porous gas nozzles on the side of the gas-liquid distribution tower plate close to the top of the cylinder and a low-speed liquid distributor penetrating the gas-liquid distribution tower plate. The low-speed liquid distributor includes an upper convex portion located on the side of the gas-liquid distribution tower plate close to the top of the cylinder, and gas-liquid two-phase outlets are provided on both sides of the upper convex portion. The lower end of the upper convex portion is connected with the gas-liquid distribution tower plate to form a channel for high-salt wastewater to enter.

[0020] The low-speed liquid distributor can adopt a convex annular gap design to increase the kinetic energy loss of water when it passes through; while the high-speed liquid distributor can adopt a concave annular gap design to reduce the kinetic energy loss of water when it passes through. The effective combination of the two allows the water to enter the upper space of the gas-liquid distributor with differential distribution. In addition, through the differentiated arrangement of the low-speed liquid distributor and the high-speed liquid distributor, the outer side of the cylinder cutting plane is a low-speed area and the inner side is a high-speed area, which promotes more seed particles to enter the circulating granulation area and regulates the seed flow direction of the circulating granulation.

[0021] Among them, the porous gas nozzle can distribute a gas flow into dispersed gas flows at various angles, helping the high-speed nitrogen gas flow to evenly enter the interior of the cylinder.

[0022] Preferably, an aerator is provided between the feed pipe and the internal space of the cylinder, the aerator comprises air inlets arranged sequentially from the outside to the inside of the cylinder and an air distribution membrane that helps acidic gas to evenly enter the inside of the cylinder, a bottom plate in close contact with the air distribution membrane is provided between the air distribution membrane and the air inlet, and a microporous outlet is provided on the air distribution membrane.

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

[0024] Ultrafine pores help to generate a large number of micro-nano bubbles. In the actual high-salinity wastewater treatment process, micro-nano bubbles can provide a large gas-liquid contact area, and the bubble rises slowly, which has good follow-up properties for seed particles. In addition, the zeta potential of the micro-nano bubble interface is high, which can adsorb organic matter in the water, avoid the entrainment of impurities in the crystallization process, and make the crystal particles more pure.

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

[0026] Preferably, the liquid guiding tube is an arc-shaped liquid guiding tube, and the nozzle is a fan-shaped nozzle.

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

[0028] Preferably, the lower guide ring is an open ring with an end closing outwards, and the upper guide ring is an open ring with an end closing inwards.

[0029] The lower guide ring is an open ring with its closing end facing outward, which forms a larger feeding area and can control the upward moving crystal particles to preferentially enter the lower fluidizing zone; while the upper guide ring is an open ring with its closing end facing inward, which reduces the probability of the crystal particles falling back into the fluidizing zone and increases the probability of falling back into the circulation zone, which is beneficial for the seed particles that rise to the junction of the circulating granulation zone and the particle separation zone to fall back to the circulation zone faster, thereby improving the circulating crystallization efficiency.

[0030] Preferably, the three-phase separator includes a feed barrel, and a guide plate arranged in the feed barrel to help separate nitrogen, wastewater and mature crystalline particles. The lower end of the feed barrel is connected to a discharge pipe that passes through the side wall of the barrel, and a solenoid valve is provided on the discharge pipe. A water outlet that passes through the side wall of the barrel is provided above the feed barrel. An exhaust pipe that passes through the top of the barrel and is arranged opposite to the water inlet pipe is also provided above the feed barrel.

[0031] The present invention also provides a method for separating metal ions from high-salinity wastewater by micro-interface induced crystallization, which uses the above-mentioned metal ion micro-interface induced crystallization separation device for high-salinity wastewater to perform separation; comprising:

[0032] (1) High-salinity wastewater enters the fluid mixing zone of the cylinder from the water inlet pipe at a differential speed under the action of the gas-liquid distributor, acidic gas enters the fluid mixing zone of the cylinder from the feed pipe, alkali liquid enters the fluid mixing zone of the cylinder from the liquid inlet pipe, and crystal seeds enter the fluid mixing zone of the cylinder from the seeding pipe. High-salinity wastewater, acidic gas, and alkali liquid react on the surface of the crystal seeds to form crystalline particles;

[0033] (2) The crystal particles move upward into the circulating granulation zone, and are continuously circulated and fluidized in the fluidizing zone and the circulation zone, and the crystals grow into mature crystal particles;

[0034] (3) The residual high-salt wastewater in the cylinder is discharged from the particle separation zone, and then the high-salt wastewater in the water inlet pipe is switched to clean water, and the entry of alkali solution and acidic gas is stopped, and nitrogen is introduced into the fluid mixing zone. 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 nitrogen, wastewater and mature crystalline particles are separated under the action of the three-phase separator;

[0035] (4) Repeat steps (1) to (3) to achieve continuous crystallization separation of metal ions in high-salinity wastewater.

[0036] Preferably, in 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 acidic gas is CO2, H2S or PH3, and the gas pressure is >0.8Mpa; the alkali solution is NaOH or KOH, and the pH is >12; the seed crystal is one or more of limestone, dolomite, calcite, garnet, quartz sand, phosphotyrite, pyrite, and the particle diameter of the seed crystal is 0.1-0.5mm.

[0037] Preferably, in step (2), the stacking height of the seed crystals in the circulating granulation zone is 0.15 to 0.2 of the total height of the circulating granulation zone, the fluid rising speed in the fluidizing zone is 40 to 60 m / h, the fluid rising speed in the circulation zone is 30 to 40 m / h, and the hydraulic retention time is 10 to 20 min; the crystallization time of mature crystalline particles is 3 to 5 days.

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

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

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

[0041] (1) The metal ion microinterface induced crystallization separation device for high-salt wastewater provided by the present invention helps high-salt wastewater enter the upper space of the gas-liquid distributor with differential distribution by means of a differential distribution gas-liquid distributor; at the same time, more crystal particles are sent into the circulating granulation area, thereby regulating the flow direction of the crystal seeds of the circulating granulation and improving the crystallization efficiency of the crystal seeds.

[0042] (2) The present invention designs a fluidized zone that is wide at the top and narrow at the bottom in the circulating granulation zone. By increasing the cross-sectional area of ​​the flow channel in the upper fluidized zone, more sufficient reaction space is provided for the crystallized particles, and the drag effect of the fluid on the seed particles is weakened, thereby extending the residence time of the crystallized particles in the upper fluidized zone.

[0043] (3) The present invention sets a three-phase separation device at the upper end of the metal ion microinterface induced crystallization separation device in high-salt wastewater, and uses the cyclonic shear field and the different accelerations generated by the mature crystal particles and the sludge particles attached to the surface of the mature crystal particles under the rotational motion to achieve the separation of the mature crystal particles and the sludge particles, desorb the sludge particles into the water phase and discharge them with the wastewater, and the obtained high-purity mature crystal particles are discharged separately from the discharge pipe.

[0044] (4) The method provided by the present invention adopts the combined use of alkaline solution + acidic gas to generate inorganic anions that react with metal ions in high-salt wastewater. On the one hand, it reduces the amount of alkaline solution added and the cost of using the agent. On the other hand, it realizes the resource utilization of acidic gas waste produced in industrial production.

[0045] (5) The method provided by the present invention does not require pH adjustment of the effluent. By controlling the flow rate of the acidic gas, it can not only meet the demand for inorganic anions in the crystallization process, but also neutralize the excess alkaline agent, thereby achieving the stability of the effluent pH, without the need to introduce a neutralizing agent for adjustment.

[0046] (6) The mature crystalline particles separated by the present invention have high purity. The separation device is provided with an aerator, and the acidic gas is converted into micro-nano bubbles through the aerator, which can provide a large gas-liquid contact area. At the same time, the bubble rises slowly, and has good followability for the seed particles. In addition, the zeta potential of the micro-nano bubble interface is high, which can adsorb organic matter in water and avoid the entrainment of impurities in the crystallization process, so that the purity of the crystalline particles is higher. BRIEF DESCRIPTION OF THE 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 various components on 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 6It is a schematic diagram of the enlarged structure of the circulating granulation zone;

[0053] Figure 7 It is an enlarged schematic diagram of the structure of a three-phase separator;

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

[0055] The codes in the figure are: cylinder 100, fluid mixing zone 110, water inlet pipe 111, seeding 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 tower plate 1153, porous gas nozzle 1154, gas-liquid two-phase outlet 1155, air inlet pipe 116, liquid vortex preventer 117, aerator 118, air inlet 1181, Chassis 1182, air distribution membrane 1183, microporous outlet 1183a, atomizer 119, liquid inlet 1191, liquid guide pipe 1192, nozzle 1193, circulating granulation zone 120, fluidizing zone 121, lower guide ring 1211, lower fluidizing zone 1212, upper fluidizing zone 1213, upper guide ring 1214, circulation zone 122, particle separation zone 130, three-phase separator 131, feed barrel 1311, guide plate 1312, discharge pipe 1313, solenoid valve 1313a, water outlet 1314, exhaust pipe 1315. DETAILED DESCRIPTION

[0056] The present invention is further described below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0057] Example 1

[0058] observe Figures 1 to 7 It can be seen that this embodiment provides a micro-interface induced crystallization separation device for metal ions in high-salinity wastewater, including a cylinder 100, in which a fluid mixing zone 110, a circulating granulation zone 120, and a particle separation zone 130 are sequentially arranged from bottom to top. The scientific arrangement of the three zones can achieve stable removal of metal ions in high-salinity wastewater, circulating fluidization induced crystallization of seed particles, and efficient desludging and separation and recovery of mature crystal particles.

[0059] observe Figure 1It can be seen that the fluid mixing zone 110 includes an inlet pipe 111 for high-salt wastewater to enter, which is arranged at the bottom of the cylinder 100. A liquid vortex preventer 117 is arranged on the outlet 1314 of the inlet pipe 111. From the bottom to the top of the cylinder 100, a feed pipe 114, a liquid inlet pipe 113 and a seeding pipe 112 are arranged in sequence. Alkali liquid enters from the liquid inlet pipe 113 arranged on the right side of the cylinder 100, acidic gas enters from the feed pipe 114 arranged on the left side of the cylinder 100, and high-salt wastewater enters from the bottom of the cylinder 100. The three react in the fluid mixing zone 110, and the crystal seeds induce the metal ions to be crystallized and the non-metallic ions or ion clusters generated by the reaction to be enriched on the surface of the crystal seeds, and further react to generate compounds with low solubility to obtain crystalline particles.

[0060] Combination Figure 1 and Figure 2 , Figure 3 It can be seen that a gas-liquid distributor 115 is provided inside the cylinder 100 and is located below the feed pipe 114. One side of the gas-liquid distributor 115 is connected to an inlet pipe 116 for nitrogen to enter and passes through a side wall of the cylinder 100. The gas-liquid distributor 115 includes a low-speed zone 1151 close to the inner wall of the cylinder 100, a high-speed zone 1152 wrapped inside the low-speed zone 1151, and a gas-liquid distribution plate 1153 that helps the low-speed zone 1151 and the high-speed zone 1152 to be arranged in a circle inside the cylinder 100. The gas-liquid distribution tray 1153 can be used as a support plate for crystal particles. At the same time, the gas-liquid distribution tray 1153 is connected with the air inlet pipe 116. The high-speed nitrogen enters the gas-liquid distribution tray 1153 from the air inlet pipe 116 for buffering and then uniformly enters the interior of the cylinder 100 from the gas-liquid distribution tray 1153 toward the porous gas nozzles 11931154 on the top side of the cylinder 100. The porous gas nozzles 11931154 can uniformly distribute a stream of gas into dispersed streams at various angles, which can be used for uniform entry of high-speed nitrogen gas.

[0061] The high-speed zone 1152 is alternately provided with a plurality of porous gas nozzles 11931154 on the side of the gas-liquid distribution plate 1153 close to the top of the cylinder 100 and a plurality of high-speed liquid distributors 1152a penetrating the gas-liquid distribution plate 1153. Each high-speed liquid distributor 1152a includes a concave portion 1152b located on the side of the gas-liquid distribution plate 1153 close to the top of the cylinder 100, and a plurality of gas-liquid two-phase outlets 1155 are provided on both sides of the concave portion 1152b, and the concave portion 1152b is connected with the gas-liquid distribution plate 1153 to form a channel for high-salinity wastewater to enter.

[0062] The low-speed zone 1151 is alternately provided with a plurality of porous gas nozzles 11931154 on the side of the gas-liquid distribution plate 1153 close to the top of the cylinder 100 and a plurality of low-speed liquid distributors 1151a penetrating the gas-liquid distribution plate 1153. Each low-speed liquid distributor 1151a includes an upper convex portion 1151b located on the side of the gas-liquid distribution plate 1153 close to the top of the cylinder 100, and a plurality of gas-liquid two-phase outlets 1155 are provided on both sides of the upper convex portion 1151b. The upper convex portion 1151b is connected with the gas-liquid distribution plate 1153 to form a channel for high-salt wastewater to enter. The low-speed liquid distributor 1151a adopts a raised annular gap design, which increases the kinetic energy loss of water flow when passing through; while the high-speed liquid distributor 1152a adopts a recessed annular gap design, which reduces the kinetic energy loss of water flow when passing through. The effective combination of the two allows the water flow to be differentially distributed and enter the upper space of the gas-liquid distributor 115. In addition, through the differentiated arrangement of the low-speed liquid distributor 1151a and the high-speed liquid distributor 1152a, the outer side of the cutting plane of the cylinder 100 is the low-speed zone 1151 and the inner side is the high-speed zone 1152, which encourages more seed particles to enter the circulating granulation zone 120 and regulates the seed flow direction of the circulating granulation.

[0063] Combination Figure 1 and Figure 6 It can be seen that the circulating granulation zone 120 includes a fluidized zone 121 arranged inside the cylinder 100 and a circulating zone 122 arranged between the fluidized zone 121 and the side wall of the cylinder 100. The fluidized zone 121 includes a lower guide ring 1211, a lower fluidized zone 1212, an upper fluidized zone 1213 and an upper guide ring 1214 arranged in sequence from the bottom to the top of the cylinder 100, and the diameter of the lower fluidized zone 1212 in the transverse direction is smaller than the diameter of the upper fluidized zone 1213 in the transverse direction. The larger diameter of the upper fluidized zone 1213 can help increase the cross-sectional area of ​​the flow channel and provide more sufficient reaction space for the crystal particles; at the same time, it can reduce the drag effect of the fluid on the seed particles and prolong the residence time of the crystal particles in the upper fluidized zone 1213. The lower guide ring 1211 is an open ring with an outward closing end, which forms a larger feeding area and can control the upward moving crystal particles to preferentially enter the lower fluidizing zone 1212; while the upper guide ring 1214 is an open ring with an inward closing end, which reduces the probability of the crystal particles falling back to the fluidizing zone 121 and increases the probability of falling back to the circulation zone 122, which is beneficial for the seed particles that have risen to the junction of the circulating granulation zone 120 and the particle separation zone 130 to fall back to the circulation zone 122 faster, thereby improving the circulating crystallization efficiency.

[0064] After the crystal particles are fully grown, the high-salt wastewater in the water inlet pipe 111 is switched to clean water, and the entry of alkali solution and acidic gas is stopped. Nitrogen is introduced into the fluid mixing area 110, and the nitrogen collected at the lower part of the cylinder 100 sends the mature crystal particles to the particle separation area 130. Figure 7As shown, the three-phase separator 131 of the particle separation zone 130 separates nitrogen, wastewater and mature crystalline particles. The three-phase separator 131 includes a feed barrel 1311, and a guide vane 1312 arranged in the feed barrel 1311 to help separate nitrogen, wastewater and mature crystalline particles. The lower end of the feed barrel 1311 is connected to a discharge pipe 1313 that penetrates the side wall of the cylinder 100, and the discharge pipe 1313 is provided with a solenoid valve 1313a. The feed barrel 1311 is provided with a water outlet 1314 that penetrates the side wall of the cylinder 100 above the feed barrel 1311, and the feed barrel 1311 is also provided with an exhaust pipe 1315 that penetrates the top of the cylinder 100 and is arranged opposite to the water inlet pipe 111. The guide vane 1312 is arranged in a circle inside the feed barrel 1311 to ensure that the generated swirl shear field can meet the separation requirements.

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

[0066] Example 2

[0067] This embodiment is based on the embodiment 1, and an aerator 118 and an atomizer 119 are added to optimize the solution. The atomizer 119 is a group of fan-shaped nozzles 1193 distributed in a circular arc shape, and the aerator 118 is a membrane type microporous aeration disk.

[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 in sequence from the outside of the cylinder 100 to the inside and an air distribution membrane 1183 that helps the acidic gas to evenly enter the cylinder 100. A bottom plate 1182 that is close to the air distribution membrane 1183 is provided between the air distribution membrane 1183 and the air inlet 1181, and a microporous outlet 1183a is provided on the air distribution membrane 1183. The air distribution membrane 1183 can be replaced when necessary to ensure aeration, greatly reducing the cost of later maintenance of the equipment. Among them, 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, an atomizer 119 is arranged between the liquid inlet pipe 113 and the internal space of the cylinder 100, and the atomizer 119 includes a liquid inlet 1191 and an arc-shaped liquid guide pipe 1192 arranged in sequence from the outside to the inside of the cylinder 100, and a fan-shaped nozzle 1193 is arranged on the arc-shaped liquid guide pipe 1192. The arc-shaped liquid guide pipe 1192 allows the alkali solution to be dispersed in the circumferential direction, and is evenly sprayed out from the fan-shaped nozzle 1193 in a tangential atomization, thereby achieving the effect of the alkali solution being three-dimensionally atomized and entering the cylinder 100.

[0070] Example 2 Method of using the separation device:

[0071] (1) When the seed crystals in the cylinder 100 are in a small particle size and irregular state. The high-salinity wastewater enters from the water inlet pipe 111 and passes through the liquid vortex preventer 117. After the speed is reduced, it is dispersed through the gas-liquid distributor 115 and enters the fluid mixing zone 110. At this time, the acidic gas enters from the feed pipe 114, and is transformed into micro-nano bubbles under the action of the aerator 118 and enters the fluid mixing zone 110; the alkali solution enters from the liquid inlet pipe 113, and is transformed into dispersed small droplets under the action of the atomizer 119 and enters the fluid mixing zone 110. After the high-salinity wastewater, acidic gas, and alkali solution come into contact in the fluid mixing zone 110, the seed crystals induce the metal ions to be crystallized and the non-metallic ions or ion clusters generated by the reaction to be enriched on the surface of the seed crystals, and further react to generate compounds with low solubility to obtain crystalline particles. Among them, the acidic gas is CO2, H2S or PH3, and the gas pressure is >0.8Mpa; the alkali solution is NaOH or KOH, and 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 crystal particles move upward and pass through the lower fluidizing zone 1212, the upper fluidizing zone 1213, and the circulation zone 122 in sequence. They are continuously circulated and fluidized in the fluidizing zone 121 and the circulation zone 122, and the crystals grow into mature crystal particles.

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

[0074]

[0075] H2S+2OH - →S 2- +2H2O

[0076]

[0077] The crystallization reaction process on the seed surface is carried out as follows:

[0078]

[0079] Cu 2+ / As 3+ +S 2- →Sulphide crystals

[0080]

[0081] (3) When a large number of mature crystalline particles appear, open the solenoid valve 1313a to discharge the residual high-salt wastewater in the cylinder 100 from the outlet 1314. Switch the high-salt wastewater in the water inlet pipe 111 to clean water, stop the entry of alkali solution and acidic gas, and introduce nitrogen into the air inlet pipe 116. The high-speed flowing gas and liquid phases are evenly dispersed in the water phase channel and the gas phase channel of the gas-liquid distributor 115, respectively, and flow 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 large sludge particles deposited at the bottom are dispersed into spherical sludge small particles. Under the drag of the mixed fluid, the mature crystalline particles and the small sludge particles are entrained through the circulating granulation area 120 and enter the three-phase separator 131 in the particle separation area 130, and the efficient desludging and separation recovery of the mature crystalline particles are achieved under the action of the self-revolution coupled centrifugal force of the cyclonic field. Finally, the solenoid valve 1313a is opened, the mature crystal particles are discharged from the discharge pipe 1313, the water phase containing the sludge particles is discharged from the outlet pipe, and the nitrogen is discharged from the exhaust pipe 1315.

[0082] (4) Repeat steps (1) to (3) to achieve continuous crystallization separation 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 per hour in a gasifier, the metal ion micro-interface induced crystallization separation device for high-salt wastewater provided in Example 2 is used, and the coal gasification ash water containing high concentrations of calcium and magnesium ions is treated as high-salt wastewater according to the above-mentioned method of use. The specific operation process and effect are described as follows:

[0085] 1. Wastewater properties and related parameters

[0086] The properties and parameters of coal gasification ash water in a certain plant under liquid phase operation are shown in Table 1.

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

[0088]

[0089] Note: Hardness and alkalinity are measured in terms of CaCO3.

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

[0091] The cylinder diameter of the metal ion micro-interface induced crystallization separation device in high-salinity wastewater is 0.3 meters, the overall height is 2.8 meters, and the processing capacity of a single unit is 1m 3 / h. A three-phase separator is installed on 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] Refer to the above "Usage of the separation device in Example 2" section, specifically: add limestone seeds with a particle size of 40-80 mesh into the seed adding tube, the stacking height is 0.3-0.4 meters, NaOH solution (pH>12) is passed into the liquid inlet pipe, CO2 gas (pressure>0.8MPa) is passed into the feed pipe, and coal gasification ash water with the composition shown in Table 1 is passed into the water inlet pipe, with a flow rate of 1m 3 / h, the fluid rising velocity in the fluidizing zone is 40m / h, the fluid rising velocity in the circulation zone is 30m / h, and the hydraulic retention time is 10min.

[0095] ②Circular granulation

[0096] The metal ion microinterface induced crystallization separation device for high-salt wastewater was operated continuously for 3 to 5 days as described in (2) of the "Usage of the separation device in Example 2", and the coal gasification ash water with the composition shown in Table 1 remaining in the cylinder was discharged from the water outlet. The coal gasification ash water in the water inlet pipe was switched to clean water (flow rate 1m 3 / h), and stop the entry of NaOH solution and CO2 gas, and introduce nitrogen (flow rate 8m 3 / h). The running time is 10-15min, the internal pressure of the cylinder is 0.2Mpa, the separation efficiency of mature crystal particles is >98%, and the particle size range is 1-3mm.

[0097] 4. Implementation Effect

[0098] The properties and parameters of the treated coal gasification ash water are shown in Table 2 below. It can be observed that the hardness and turbidity are significantly reduced, the reduction rate of total hardness and turbidity can reach more than 85%, the COD removal rate is >55%, and the pH value and alkalinity are slightly improved. In addition, the suspended matter content of the coal gasification ash water increases after separation treatment; the reason is that the micro-nano bubbles make the colloidal particles in the ash water aggregate and grow into suspended particles, a small part of which sinks with the crystallized sediment, and most of it rises to the outlet with the ash water. Therefore, a three-phase separator is set at the end of the crystallization separation device. On the one hand, the suspended matter in the softened effluent can be removed, and on the other hand, the muddy wastewater after the mature crystal particles are desludged can be purified.

[0099] Table 2 Properties and parameters of coal gasification ash water after treatment in a certain plant

[0100]

Claims

1. A device for separating metal ions from high-salinity wastewater by microinterface induced crystallization, characterized in that: It comprises a cylinder, in which a fluid mixing zone, a circulating granulation zone, and a particle separation zone are sequentially arranged from bottom to top; The fluid mixing zone includes an inlet pipe arranged at the bottom of the cylinder for high-salt wastewater to enter and a seeding pipe arranged on the side wall of the cylinder; the high-salt wastewater in the inlet pipe is differentially distributed toward the top of the cylinder under the action of the gas-liquid distributor and enters the fluid mixing zone, and is mixed with the seeds entering the fluid mixing zone through the seeding pipe, and reacts in the fluid mixing zone with the assistance of alkaline solution and acidic gas to obtain crystalline particles; the crystalline particles move upward into the circulating granulation zone to grow into mature crystalline particles, and one side of the gas-liquid distributor is connected to an inlet pipe for nitrogen to enter and penetrate one side wall of the cylinder. 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 that helps separate gas, wastewater and mature crystalline particles.

2. The metal ion microinterface induced crystallization separation device in high-salt wastewater according to claim 1, characterized in that: The fluid mixing zone also includes a liquid inlet pipe for entering the alkali solution and a feed pipe for entering the acidic gas. The liquid inlet pipe and the feed pipe are arranged relatively on the side wall of the cylinder. A gas-liquid distributor is arranged inside the cylinder and the gas-liquid distributor is located below the feed pipe. The seeding pipe is arranged above the feed pipe, and a liquid vortex preventer is arranged on the water outlet of the water inlet pipe.

3. The metal ion microinterface induced crystallization separation device in high-salt wastewater according to claim 1 or 2, characterized in that: The gas-liquid distributor comprises a low-speed zone close to the inner wall of the cylinder, a high-speed zone wrapped inside the low-speed zone, and a gas-liquid distribution tower plate which helps the low-speed zone and the high-speed zone to be arranged in the cylinder.

4. The metal ion microinterface induced crystallization separation device in high-salt wastewater according to claim 3, characterized in that: The high-speed zone is alternately provided with porous gas nozzles on the side of the gas-liquid distribution plate close to the top of the cylinder and a high-speed liquid distributor penetrating the gas-liquid distribution plate, the high-speed liquid distributor includes a concave portion located on the side of the gas-liquid distribution plate close to the top of the cylinder, gas-liquid two-phase outlets are arranged on both sides of the concave portion, and the lower end of the concave portion is connected with the gas-liquid distribution plate to form a channel for high-salt wastewater to enter; The low-speed zone is alternately provided with porous gas nozzles on the side of the gas-liquid distribution tower plate close to the top of the cylinder and a low-speed liquid distributor penetrating the gas-liquid distribution tower plate. The low-speed liquid distributor includes an upper convex portion located on the side of the gas-liquid distribution tower plate close to the top of the cylinder, and gas-liquid two-phase outlets are provided on both sides of the upper convex portion. The lower end of the upper convex portion is connected with the gas-liquid distribution tower plate to form a channel for high-salt wastewater to enter.

5. The device for separating metal ions from high-salinity wastewater by microinterface induced crystallization according to claim 2, characterized in that: An aerator is provided between the feed pipe and the internal space of the cylinder, and the aerator includes air inlets arranged sequentially from the outside to the inside of the cylinder and an air distribution membrane that helps acidic gas to evenly enter the inside of the cylinder, a bottom plate that is closely attached to the air distribution membrane is provided between the air distribution membrane and the air inlet, and a microporous outlet is provided on the air distribution membrane.

6. The device for separating metal ions from high-salinity wastewater by microinterface induced crystallization according to claim 2, characterized in that: An atomizer is arranged between the liquid inlet pipe and the inner space of the cylinder. The atomizer comprises a liquid inlet and a liquid guide pipe which are arranged in sequence from the outside to the inside of the cylinder. A nozzle is arranged on the liquid guide pipe.

7. The metal ion microinterface induced crystallization separation device in high-salt wastewater according to claim 1, characterized in that: The circulating granulation zone includes a fluidizing zone arranged inside the cylinder and a circulation zone arranged between the fluidizing zone and the side wall of the cylinder, the fluidizing zone includes a lower guide ring, a lower fluidizing zone, an upper fluidizing zone and an upper guide ring arranged in sequence from the bottom to the top of the cylinder, and the transverse diameter of the lower fluidizing zone is smaller than the transverse diameter of the upper fluidizing zone.

8. The metal ion microinterface induced crystallization separation device in high-salt wastewater according to claim 1, characterized in that: The three-phase separator includes a feed barrel, and a guide plate arranged in the feed barrel to help separate nitrogen, wastewater and mature crystalline particles. The lower end of the feed barrel is connected to a discharge pipe that passes through the side wall of the barrel, and a solenoid valve is provided on the discharge pipe. A water outlet that passes through the side wall of the barrel is provided above the feed barrel. An exhaust pipe that passes through the top of the barrel and is arranged opposite to the water inlet pipe is also provided above the feed barrel.

9. A method for separating metal ions from high-salinity wastewater by microinterface induced crystallization, characterized in that: The separation is performed using the metal ion microinterface induced crystallization separation device in high-salt wastewater as claimed in any one of claims 1 to 8; comprising: (1) High-salinity wastewater enters the fluid mixing zone of the cylinder from the water inlet pipe at a differential speed under the action of the gas-liquid distributor, acidic gas enters the fluid mixing zone of the cylinder from the feed pipe, alkali liquid enters the fluid mixing zone of the cylinder from the liquid inlet pipe, and crystal seeds enter the fluid mixing zone of the cylinder from the seeding pipe. High-salinity wastewater, acidic gas, and alkali liquid react on the surface of the crystal seeds to form crystalline particles; (2) The crystal particles move upward into the circulating granulation zone, and are continuously circulated and fluidized in the fluidizing zone and the circulation zone, and the crystals grow into mature crystal particles; (3) The residual high-salt wastewater in the cylinder is discharged from the particle separation zone, and then the high-salt wastewater in the water inlet pipe is switched to clean water, and the entry of alkali solution and acidic gas is stopped, and nitrogen is introduced into the fluid mixing zone. 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 nitrogen, wastewater and mature crystalline particles are separated under the action of the three-phase separator; (4) Repeat steps (1) to (3) to achieve continuous crystallization separation of metal ions in high-salinity wastewater.

10. The separation method of metal ion microinterface induced crystallization in high-salinity wastewater according to claim 9, characterized in that: 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 acidic gas is CO2, H2S or PH3, and the gas pressure is >0.8Mpa; the alkali solution is NaOH or KOH, and the pH is >12; the seed crystal is one or more of limestone, dolomite, calcite, garnet, quartz sand, phosphorite, pyrite, and the particle diameter of the seed crystal is 0.1-0.5mm; In the step (2), the stacking height of the seed crystals in the circulating granulation zone is 0.15 to 0.2 of the total height of the circulating granulation zone, the fluid rising speed in the fluidizing zone is 40 to 60 m / h, the fluid rising speed in the circulation zone is 30 to 40 m / h, and the hydraulic retention time is 10 to 20 min; the crystallization time of the mature crystalline particles is 3 to 5 days; In the step (3), the flow rate of clean water is the same as the treatment amount of high-salt wastewater, the flow rate of nitrogen is 8 to 10 times the flow rate of clean water, the internal pressure of the cylinder is 0.2 to 0.3 MPa; the separation time of the three-phase separator is 10 to 15 minutes, and the separation efficiency is >98%; the particle size of the mature crystalline particles is 1 to 3 mm, the water content is <0.5%, and the compressive strength is 40 to 60 MPa; In the step (4), the separation efficiency of metal ions in high-salt wastewater is >95%.

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