A catalytic oxidation reactor for the polymerization of ferric sulfate

Abstract

The application discloses a catalytic oxidation reaction device for polymerization of iron sulfate, which comprises a reaction kettle and a gas-liquid mixer, wherein the gas-liquid mixer is communicated with the reaction kettle through a discharge port; the flow area of the gas-liquid mixer is linearly reduced along the flow direction of fluid, and a first feeding port and a second feeding port are arranged on the gas-liquid mixer; the first feeding port is connected with a slurry circulation module, the inlet end of the slurry circulation module is communicated with a discharge pipe on the reaction kettle; the second feeding port is connected with a nitrogen oxide recovery module, the nitrogen oxide recovery module is communicated with the reaction kettle; an oxygen conveying module for conveying oxygen for the reaction is further arranged on the reaction kettle; and the reaction device further comprises a detection control module, which is electrically connected with the slurry circulation module, the nitrogen oxide recovery module and the oxygen conveying module respectively; compared with the prior art, the application realizes rapid and uniform mixing of the slurry and gaseous nitrogen oxide through the Venturi effect, so that the production efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of inorganic polymer flocculant production equipment, specifically to a catalytic oxidation reaction device for polyferric sulfate. Background Technology

[0002] Polyferric sulfate (PFS) is a novel and highly efficient inorganic polymeric flocculant that can be used for coagulation and sedimentation treatment of wastewater as well as for the purification of drinking water. Currently, PFS is mainly produced using two methods: direct oxidation and catalytic oxidation. The raw material cost of direct oxidation is higher than that of catalytic oxidation, therefore catalytic oxidation is more commonly used.

[0003] The catalytic oxidation method uses sodium nitrite as a catalyst to oxidize ferrous sulfate to polyferric sulfate. To advance the reaction, pure oxygen needs to be added to promote the oxidation process. However, due to issues with the uniformity of material mixing, Fe²⁺… + Oxidized to Fe³ + The process is slow, resulting in low production efficiency of polyferric sulfate. Utility Model Content

[0004] The main objective of this application is to provide a catalytic oxidation reaction device for polyferric sulfate, which aims to solve the defects of the prior art, such as long reaction cycle, high energy consumption and high production cost.

[0005] This application achieves the above objectives through the following technical solutions: A catalytic oxidation reaction apparatus for polyferric sulfate, comprising a reaction vessel; A gas-liquid mixer is provided, with its outlet connected to the reactor. The flow area of ​​the gas-liquid mixer decreases linearly along the fluid flow direction. The gas-liquid mixer is connected to the slurry circulation module via a first inlet. The reactor is also equipped with a discharge pipe connected to the inlet of the slurry circulation module. The gas-liquid mixer is also connected to a nitrogen oxide recovery module via a second inlet. The inlet of the nitrogen oxide recovery module is connected to the reactor to achieve the recycling of nitrogen oxides. An oxygen delivery module is connected to the reactor to continuously supply oxygen for the reaction into the reactor. The detection and control module is electrically connected to the slurry circulation module, the nitrogen oxide recovery module, and the oxygen delivery module, respectively.

[0006] Optionally, a safety valve, a catalyst filling port, and a pressure gauge are also installed on the top of the reactor.

[0007] Optionally, a bypass pipe for connecting the slurry circulation module is also provided in parallel on the discharge pipe; both the bypass pipe and the discharge pipe are provided with regulating valves that are electrically connected to the controller.

[0008] Optionally, the gas-liquid mixer includes a mixing pipe, a spray pipe, and a suction pipe. The mixing pipe includes a first pipe body, a conical pipe, and a second pipe body connected coaxially in sequence. The large end of the conical pipe is connected to the first pipe body, and its small end is connected to the second pipe body. The spray pipe is coaxially inserted into the first pipe body, and its outlet end faces the second pipe body. The suction pipe is connected to the first pipe body along the radial direction of the first pipe body.

[0009] Optionally, the slurry circulation module includes a circulation pump and a circulation pipe that are interconnected. The inlet end of the injection pipe is a first feed port, the outlet end of the circulation pipe is connected to the first feed port, and the circulation pump is electrically connected to the controller.

[0010] Optionally, the nitrogen oxide recovery module includes an induced draft fan and a gas storage tank; along the airflow direction, the induced draft fan and the gas storage tank are connected in series; the inlet end of the suction pipe is a second feed port, and the outlet end of the gas storage tank is connected to the second feed port through a return gas pipe.

[0011] Optionally, the nitrogen oxide recovery module also includes a gas compressor, which is located between the induced draft fan and the gas storage tank; both the inlet and outlet ends of the gas storage tank are equipped with regulating valves electrically connected to the controller.

[0012] Optionally, the oxygen delivery module includes an oxygen delivery pipe, on which an oxygen mass flow meter is installed; the outlet end of the oxygen delivery pipe is connected to the reactor, and its inlet end is connected to an external gas source.

[0013] Optionally, the oxygen delivery module further includes several independent tangential gas pipes, the inlet end of each tangential gas pipe being connected to the oxygen delivery pipe, and the outlet end being inserted into the reactor along the tangential direction of the inner wall of the reactor; the outlet end of each tangential gas pipe is inclined towards the bottom of the reactor, and the angle between it and the horizontal plane increases linearly.

[0014] Optionally, the detection and control module includes an ORP detector and a PLC automatic control system, wherein the ORP detector is connected to the discharge pipe; and the ORP detector is electrically connected to the PLC automatic control system.

[0015] Compared with the prior art, this application has the following beneficial effects: This application includes a reaction vessel and a gas-liquid mixer, wherein the outlet of the gas-liquid mixer is connected to the reaction vessel; the flow area of ​​the gas-liquid mixer decreases linearly along the flow direction of the fluid, and the gas-liquid mixer is provided with a first inlet and a second inlet; the first inlet is connected to a slurry circulation module, and the inlet end of the slurry circulation module is connected to a discharge pipe on the reaction vessel; the second inlet is connected to a nitrogen oxide recovery module, and the nitrogen oxide recovery module is connected to the reaction vessel; the reaction vessel is also provided with an oxygen delivery module for connecting to the oxygen used for the reaction; the reaction device also includes a detection and control module, which is electrically connected to the slurry circulation module, the nitrogen oxide recovery module and the oxygen delivery module respectively.

[0016] In use, the initial reactants are first added to the reactor. As the reaction proceeds, the raw materials in the reactor are drawn into the gas-liquid mixer through the slurry circulation module. At the same time, the gaseous nitrogen oxides generated during the reaction are recovered by the nitrogen oxide recovery module. Since the flow area of ​​the gas-liquid mixer decreases linearly along the flow direction of the fluid, a vacuum zone is formed in the gas-liquid mixer when the slurry passes through it rapidly, based on the Venturi effect. This allows the gaseous nitrogen oxides to be extracted and recovered. The gas is sheared and torn into extremely small bubbles (usually up to the micrometer level) by the high-speed liquid flow. As the flow rate decreases and the pressure increases in the diffusion section, these microbubbles can dissolve or disperse more stably and uniformly in the slurry, avoiding short-circuiting and escape of large bubbles. This achieves a high degree of micro-mixing of the gas and liquid phases and improves production efficiency.

[0017] Secondly, the reuse of NO The re-entry of gas into the reactor increases the reactant concentration, providing more substrate for the polyferric catalyst (such as polyferric sulfate, PFS), allowing it to exert its catalytic oxidation effect more fully and thus improving the overall catalytic reaction rate of the system. Finally, this application can ensure that ferrous iron is always in a highly efficient oxidation state throughout the entire reaction process by controlling the circulation volume of the slurry circulation module, and at the same time, it can control the entire reaction process and achieve precise control of the entire reaction process. Attached Figure Description

[0018] Figure 1 A schematic diagram of a catalytic oxidation reactor for polyferric sulfate provided in this application embodiment; Figure 2 This is a schematic diagram of a gas-liquid mixer. Figure 3 This is a cross-sectional view of a gas-liquid mixer; Figure reference numerals: 1-Reaction vessel, 2-Gas-liquid mixer, 3-Outlet, 4-First inlet, 5-Slurry circulation module, 6-Discharge pipe, 7-Second inlet, 8-Nitrogen oxide recovery module, 9-Oxygen delivery module, 10-Detection and control module, 11-Safety valve, 12-Catalyst filling port, 13-Pressure gauge, 14-Bypass pipe, 15-Regulating valve, 201-Mixing pipe, 202-Injection pipe, 2 03-Suction tube, 2011-First tube body, 2012-Cone tube, 2013-Second tube body, 501-Circulation pump, 502-Circulation pipe, 801-Exhaust fan, 802-Gas storage tank, 803-Return gas pipe, 804-Gas compressor, 901-Oxygen delivery pipe, 902-Oxygen mass flow meter, 903-Tangential gas pipe, 1001-ORP detector, 1002-PLC automatic control system.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions. Taking "robot coordinate system and / or m" as an example, it includes a robot coordinate system solution, an m solution, or a solution where both the robot coordinate system and m are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0024] Implementation Method 1 Reference Figures 1 to 3 This embodiment, as an optional embodiment of this application, discloses a catalytic oxidation reaction device for polyferric sulfate, including a reaction vessel 1; a safety valve 11, a catalyst filling port 12 and a pressure gauge 13 are provided at the top of the reaction vessel 1; a discharge pipe 6 is provided at the bottom of the reaction vessel 1, and a bypass pipe 14 is connected in parallel to the discharge pipe 6. The reaction device further includes a gas-liquid mixer 2 and a slurry circulation module 5. The gas-liquid mixer 2 includes a mixing pipe 201, a spray pipe 202, and a suction pipe 203. The mixing pipe 201 includes a first pipe body 2011, a conical pipe 2012, and a second pipe body 2013 connected coaxially in sequence. The large end of the conical pipe 2012 is connected to the first pipe body 2011, and its small end is connected to the second pipe body 2013. That is, the inner diameter of the second pipe body 2013 is smaller than the inner diameter of the first pipe body 2011. The two are smoothly connected by the conical pipe 2012 to ensure that the flow area of ​​the gas-liquid mixer 2 decreases linearly along the flow direction of the fluid.

[0025] The outlet end of the spray pipe 202 is inserted into the mixing pipe 201 along the axial direction of the mixing pipe 201, and the spray pipe 202 is coaxial with the mixing pipe 201. The outlet end of the spray pipe 202 is directly opposite the second pipe body 2013, and the inlet end of the spray pipe 202 is the first feed port 4. Along the radial direction of the first tube body 2011, the outlet end of the suction tube 203 is inserted into the mixing tube 201 and communicates with the first tube body 2011. In the above structure, the mixing tube 201 is equivalent to a Venturi tube, which realizes rapid and uniform mixing of materials through the Venturi effect. The entire device has a simple structure and effectively improves the stability and reliability of the equipment. The outlet end of the second tube 2013 is the discharge port 3 of the gas-liquid mixer 2, and the discharge port 3 is inserted into the reactor 1.

[0026] Furthermore, the slurry circulation module 5 includes a circulation pump 501 and a circulation pipe 502. The inlet end of the circulation pipe 502 is connected to the outlet end of the circulation pump 501, and its outlet end is connected to the first feed port 4. The inlet end of the circulation pump 501 is connected to the bypass pipe 14, and a regulating valve 15 for controlling its on / off state is also provided on the bypass pipe 14. Furthermore, the reaction device also includes a nitrogen oxide recovery module 8, which includes an induced draft fan 801 and a gas storage tank 802. The inlet end of the induced draft fan 801 is connected to the gas storage area above the reaction vessel 1, and its outlet end is connected to the gas storage tank 802. That is, along the airflow direction, the induced draft fan 801 and the gas storage tank 802 are connected in series. The outlet end of the gas storage tank 802 is connected to the second feed port 7 through the return gas pipe 803; the return gas pipe 803 is also provided with a regulating valve 15 for controlling its on / off state. Furthermore, the nitrogen oxide recovery module 8 also includes a gas compressor 804, which is disposed between the induced draft fan 801 and the gas storage tank 802, and a regulating valve 15 is also disposed between the gas compressor 804 and the gas storage tank 802. The gaseous nitrogen oxides accumulated at the top of the reactor 1 can be drawn out by the induced draft fan 801, and then pressurized by the gas compressor 804 and stored in the gas storage tank 802, thereby realizing the recycling of gaseous nitrogen oxides. At the same time, the pressurized storage method can not only increase the storage capacity, but also release the high-pressure gas on its own when used later, thereby improving the conveying efficiency of gaseous nitrogen oxides.

[0027] Furthermore, the reaction apparatus also includes an oxygen delivery module 9, which includes an oxygen delivery pipe 901. The inlet end of the oxygen delivery pipe 901 is connected to an external oxygen source, and its outlet end is connected in parallel to several tangential gas pipes 903. The outlet end of each tangential gas pipe 903 is inserted into the reaction vessel 1 along the tangential direction of the inner wall of the reaction vessel 1. At the same time, the outlet end of each tangential gas pipe 903 is inclined towards the bottom of the reaction vessel 1, and the angle between it and the horizontal plane increases linearly. For example, the inclination angle of the tangential gas pipe 903 located at the top is 15°, and the inclination angles of the second and third stages increase according to a fixed angle. Furthermore, an oxygen mass flow meter 902 is also installed on the oxygen delivery pipe 901 to realize real-time monitoring of the oxygen delivery volume. By utilizing the initial momentum of the gas upon entry through the tangential gas pipe 903, i.e. the downward momentum component, the gas is carried into a deeper region of the reactor 1, enhancing axial circulation and preventing the gas from accumulating on the surface prematurely. This further prolongs the residence time, thereby maximizing the residence time, dissolution rate, and circulation efficiency of oxygen.

[0028] Furthermore, the reaction apparatus also includes a detection and control module 10, which includes an ORP detector 1001 and a PLC automatic control system 1002. The ORP detector 1001 is connected to the discharge pipe 6; the ORP detector 1001 is electrically connected to the PLC automatic control system 1002; the PLC automatic control system 1002 includes an industrial control computer and a PLC, and the industrial control computer is communicatively connected to the PLC. The PLC is electrically connected to each regulating valve 15, ORP detector 1001, circulating pump 501, induced draft fan 801 and gas compressor 804 to realize automatic control of the entire system.

[0029] Accordingly, this application also discloses a catalytic oxidation method based on the above-mentioned catalytic oxidation reactor, comprising the following steps: S1. System startup, initial feeding, and slurry circulation; The prepared ferrous sulfate slurry is fed into the reactor via a feed pump, filling the reactor to 70%-80% of its effective volume. The slurry circulation pump is then started to circulate the slurry within the reactor, with a total slurry circulation frequency of 3-5 minutes per cycle.

[0030] The PLC automatic control system is activated, and a certain amount of recovered nitrogen oxides is added to the reactor through the nitrogen oxide recovery module to maintain a slightly positive reaction pressure. Simultaneously, a small amount of sodium nitrite solution is added to the reactor.

[0031] S2, gas-liquid mixing and cyclic oxidation The slurry passes through the venturi throat at high speed, creating a negative pressure zone (vacuum degree approximately -0.02 to -0.05 MPa) that draws in nitrogen oxides and oxygen from the reactor. The intake flow rate of oxygen and nitrogen oxides is precisely controlled by a mass flow meter (MFM). The flow rate of the tangential oxygen inlet pipe is controlled by an oxygen regulating valve to stabilize the reactor pressure at approximately 0.1-0.3 MPa.

[0032] The PLC receives real-time signals from the ORP detector and dynamically adjusts the frequency of the metering pump or the opening of the regulating valve to stabilize the redox potential of the reaction system within the set range.

[0033] S3: Gas Recovery and Reuse When the pressure inside the reactor suddenly changes and the reaction reaches its endpoint, the PLC control system activates the nitrogen oxide recovery module to recover the unreacted nitrogen oxide gas inside the reactor. The system recovers the gas through an induced draft fan and a gas compressor. The recovered gas is temporarily stored in a storage tank for reuse in the next batch of production.

[0034] The gas collection efficiency of the recovery system is >90%, minimizing waste gas emissions and treatment volume.

[0035] S4: Reaction Process Control and Optimization The PLC system monitors key parameters inside the reactor in real time, such as pressure control at 0.1-0.3 MPa, ORP value maintained at 300-500 mV (relative to the Ag / AgCl reference electrode), which is a key indicator for judging the degree of Fe²⁺ oxidation, and nitrogen oxide pressure within the nitrogen oxide recovery module, adjusting the opening of the nitrogen oxide valve on the recovery pipeline according to the system internal pressure.

[0036] S5: Reaction Termination and Product Output When the pressure inside the reactor suddenly changes, reaching the reaction endpoint, the PLC automatically shuts down the oxygen mass flow meter and the slurry circulation pump. At the same time, the nitrogen oxide recovery system recovers the excess nitrogen oxides from the reaction system, and the reaction is complete.

[0037] The finished polyferric sulfate solution is transported to the finished product storage tank. The entire reaction cycle takes approximately 2-3 hours depending on the amount of feed, which is 20%-50% shorter than traditional methods. Furthermore, the nitrogen oxide recovery process reduces the residual nitrogen oxides in the finished polyferric sulfate, providing more options for product applications. Nitrogen oxide recovery also reduces the amount of sodium nitrite used, lowering production costs.

[0038] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A catalytic oxidation reaction apparatus for polyferric sulfate, characterized in that, Including the reaction vessel (1); A gas-liquid mixer (2) is provided, the outlet (3) of which is connected to the reactor (1); the flow area of ​​the gas-liquid mixer (2) decreases linearly along the flow direction of the fluid; the gas-liquid mixer (2) is connected to the slurry circulation module (5) through the first inlet (4); the reactor (1) is also provided with a discharge pipe (6) connected to the inlet end of the slurry circulation module (5); the gas-liquid mixer (2) is connected to the nitrogen oxide recovery module (8) through the second inlet (7); the inlet end of the nitrogen oxide recovery module (8) is connected to the reactor (1) to realize the recycling of nitrogen oxides; An oxygen delivery module (9) is connected to the reactor (1) to continuously supply oxygen for the reaction into the reactor (1); The detection control module (10) is electrically connected to the slurry circulation module (5), the nitrogen oxide recovery module (8), and the oxygen delivery module (9), respectively.

2. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 1, characterized in that, The top of the reactor (1) is also equipped with a safety valve (11), a catalyst filling port (12), and a pressure gauge (13).

3. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 1, characterized in that, A bypass pipe (14) for connecting the slurry circulation module (5) is also provided in parallel on the discharge pipe (6); both the bypass pipe (14) and the discharge pipe (6) are provided with regulating valves (15) that are electrically connected to the detection and control module (10).

4. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 1, characterized in that, The gas-liquid mixer (2) includes a mixing pipe (201), an injection pipe (202), and a suction pipe (203). The mixing pipe (201) includes a first pipe body (2011), a conical pipe (2012), and a second pipe body (2013) connected coaxially in sequence. The large end of the conical pipe (2012) is connected to the first pipe body (2011), and its small end is connected to the second pipe body (2013). The injection pipe (202) is coaxially inserted into the first pipe body (2011), and its outlet end faces the second pipe body (2013). The suction pipe (203) is connected to the first pipe body (2011) along the radial direction of the first pipe body (2011).

5. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 4, characterized in that, The slurry circulation module (5) includes a circulation pump (501) and a circulation pipe (502) that are connected to each other. The inlet end of the injection pipe (202) is the first feed port (4), and the outlet end of the circulation pipe (502) is connected to the first feed port (4). The circulation pump (501) is electrically connected to the detection and control module (10).

6. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 4, characterized in that, The nitrogen oxide recovery module (8) includes an induced draft fan (801) and a gas storage tank (802); along the airflow direction, the induced draft fan (801) and the gas storage tank (802) are connected in series; the inlet end of the suction pipe (203) is the second feed port (7), and the outlet end of the gas storage tank (802) is connected to the second feed port (7) through the return air pipe (803).

7. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 6, characterized in that, The nitrogen oxide recovery module (8) also includes a gas compressor (804), which is located between the induced draft fan (801) and the gas storage tank (802); the inlet and outlet ends of the gas storage tank (802) are equipped with regulating valves (15) that are electrically connected to the detection and control module (10).

8. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 1, characterized in that, The oxygen delivery module (9) includes an oxygen delivery pipe (901), on which an oxygen mass flow meter (902) is installed; the outlet end of the oxygen delivery pipe (901) is connected to the reactor (1), and its inlet end is connected to an external gas source.

9. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 8, characterized in that, The oxygen delivery module (9) also includes several independent tangential gas pipes (903). The inlet end of each tangential gas pipe (903) is connected to the oxygen delivery pipe (901), and its outlet end is inserted into the reactor (1) along the tangential direction of the inner wall of the reactor (1). The outlet end of each tangential gas pipe (903) is inclined towards the bottom of the reactor (1), and the angle between it and the horizontal plane increases linearly.

10. The catalytic oxidation reaction apparatus for polyferric sulfate according to claim 1, characterized in that, The detection control module (10) includes an ORP detector (1001) and a PLC automatic control system (1002). The ORP detector (1001) is connected to the discharge pipe (6). The ORP detector (1001) is electrically connected to the PLC automatic control system (1002).

Images