A phosphoric acid dropping device for preparation of tributyl phosphate

Abstract

This application discloses a phosphoric acid dripping device for the preparation of tributyl phosphate, comprising a high-level phosphoric acid storage tank, a metering pump, and an inert gas supply assembly. The metering pump is fixedly connected to the bottom of the high-level phosphoric acid storage tank. The metering pump is used to deliver phosphoric acid from the high-level phosphoric acid storage tank to the esterification reactor at a precise and controllable flow rate. In order to solve the technical problem in the prior art that ordinary dripping equipment causes inaccurate flow rate of the metering pump due to the volatility, corrosiveness, and viscosity variation of phosphoric acid when dripping phosphoric acid, this application designs a dripping device with pressure stabilization function. By setting the pressure transmitter assembly, the pressure inside the tank can be automatically maintained at a constant value. It does not require external power or compressed air drive, has a simple structure, and is easy to maintain, making it particularly suitable for use in the synthesis process of tributyl phosphate.

Description

Technical Field

[0001] This application relates to the field of chemical production equipment technology, and in particular to a phosphoric acid dropping device for the preparation of tributyl phosphate. Background Technology

[0002] Tributyl phosphate is an important chemical product and extractant. Its preparation process usually involves the esterification reaction of phosphoric acid and butanol. In this reaction, the dropping rate and stability of phosphoric acid are key factors affecting the reaction conversion rate, product purity and by-product formation. Industrially, phosphoric acid is often added to the reaction vessel by means of a high-level tank combined with a metering pump in order to achieve controlled feeding.

[0003] However, high-concentration phosphoric acid has some special physicochemical properties. When added dropwise, phosphoric acid easily absorbs moisture from the air and becomes diluted. Furthermore, exposure to air may pose an oxidation risk, which can lead to deviations in the concentration of materials participating in the reaction and affect product quality.

[0004] Meanwhile, in existing dripping devices, the static pressure difference of the high-level tank is generally relied upon to provide inlet power for the metering pump. As dripping proceeds, the liquid level in the high-level tank continuously decreases, and the static pressure head generated also decreases accordingly, causing the inlet pressure of the metering pump to fluctuate continuously. The outlet flow rate of the metering pump is very sensitive to its inlet pressure, and fluctuations in the inlet pressure will directly affect the accuracy of its output flow rate. In severe cases, it may even cause cavitation of the pump, damaging the equipment and interrupting production.

[0005] In other words, existing technologies have the following technical problems: ordinary phosphoric acid dropping equipment suffers from fluctuations in pump inlet pressure due to changes in liquid level, which in turn affects the dropping accuracy. Therefore, to address the above problems, a phosphoric acid dropping device for the preparation of tributyl phosphate is proposed. Utility Model Content

[0006] This embodiment provides a phosphoric acid dropping device for the preparation of tributyl phosphate, which solves the problem in the prior art of ordinary phosphoric acid dropping equipment that the pump inlet pressure fluctuates due to changes in liquid level, thus affecting the dropping accuracy.

[0007] A phosphoric acid dripping device for the preparation of tributyl phosphate includes a high-level support frame and an inert gas supply assembly. A high-level phosphoric acid storage tank is fixedly installed at the top of the high-level support frame. A metering pump is fixedly connected to the bottom of the high-level phosphoric acid storage tank. One end of an input pipe is fixedly connected to the input end of the metering pump. The other end of the input pipe is fixedly connected to the bottom of the inner cavity of the high-level phosphoric acid storage tank. A dripping output pipe is fixedly connected to the output end of the metering pump. The inert gas supply assembly includes an inert gas source, a delivery connecting pipe, and a gas flow limiting pipe. The inert gas source is fixedly connected to one end of the delivery connecting pipe, and the other end of the delivery connecting pipe is fixedly connected to the gas flow limiting pipe. The gas flow limiting pipe is fixedly connected to the upper end of the inner cavity of the high-level phosphoric acid storage tank. A pressure transmitter assembly is also installed between the high-level phosphoric acid storage tank and the gas flow restriction pipeline. The pressure transmitter assembly includes a press control valve and a movable press contact plate. The press contact plate is used to directly press or release the valve core of the press control valve under the drive of the pressure transmitter assembly, thereby controlling the opening and closing of the gas flow restriction pipeline.

[0008] The phosphoric acid dripping device for the preparation of tributyl phosphate is further equipped with a valve at the delivery connection pipe.

[0009] The phosphoric acid dropping device for the preparation of tributyl phosphate, wherein the press control valve is fixedly installed on the gas flow limiting pipeline, and the press control valve is a normally closed mechanical valve.

[0010] The phosphoric acid dripping device for the preparation of tributyl phosphate includes a pressure transmitter assembly that further comprises a fixed cylinder and a movable piston. The fixed cylinder is fixedly installed on the upper surface of the high-level phosphoric acid storage tank, and the movable piston is slidably connected in the inner cavity of the fixed cylinder. The top of the high-level phosphoric acid storage tank is also provided with a safety valve that is directly connected to the inner cavity of the high-level phosphoric acid storage tank.

[0011] The phosphoric acid dripping device for the preparation of tributyl phosphate has a connecting pipe fixedly connected to the bottom of the inner cavity of the fixed cylinder, and the other end of the connecting pipe extends into the inner cavity of the high-level phosphoric acid storage tank and is fixedly connected to the high-level phosphoric acid storage tank.

[0012] The phosphoric acid dropping device for the preparation of tributyl phosphate has a supporting guide plate fixedly connected to both sides of the upper surface of the moving piston. The top of the supporting guide plate penetrates the upper wall of the inner cavity of the fixed cylinder and extends to the outside of the wall. The tops of the two supporting guide plates are fixedly connected to the bottom surface of the pressing contact plate.

[0013] The phosphoric acid dropping device for the preparation of tributyl phosphate has a control spring fixedly installed on the upper surface of the moving piston.

[0014] The phosphoric acid dropping device for the preparation of tributyl phosphate is provided with an adjustment part in the control spring. The adjustment part includes an adjustment slider and an adjustment screw. The adjustment slider is disposed in the inner cavity of the fixed cylinder and slides with the fixed cylinder. The adjustment screw is rotatably connected to the upper wall of the inner cavity of the fixed cylinder. The adjustment screw passes through the adjustment slider and is threaded with the adjustment slider. A through hole communicating with the outside is provided on the upper side of the inner cavity of the fixed cylinder.

[0015] In the phosphoric acid dropping device for the preparation of tributyl phosphate, the top end of the control spring abuts against the lower surface of the adjusting slider.

[0016] The phosphoric acid dripping device for the preparation of tributyl phosphate has a first bevel gear fixedly connected to the arc-shaped wall of the adjusting screw, an adjusting knob rotatably connected to the outer wall of the fixed cylinder, one end of the adjusting knob extending into the inner cavity of the fixed cylinder, and a second bevel gear fixedly connected to one end of the adjusting knob, the second bevel gear meshing with the first bevel gear.

[0017] In order to solve the technical problem of inaccurate metering pump flow caused by pressure fluctuations in ordinary dripping equipment when dripping phosphoric acid, due to the volatility, corrosiveness and viscosity variation of phosphoric acid with concentration, the present application designs a dripping equipment with pressure stabilization function. By setting the pressure transmitter component, it can automatically maintain the constant pressure in the tank, and does not require external power or compressed air drive. It has a simple structure and is easy to maintain, and is particularly suitable for use in the synthesis process of tributyl phosphate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a three-dimensional structural diagram of the present invention; Figure 3 This is a front view structural diagram of the present invention; Figure 4 for Figure 2 A magnified schematic diagram of the partial structure at point A in the middle; Figure 5 This is a schematic diagram of the structure of the fixed cylinder body of this utility model; Figure 6 This is a schematic diagram of the structure of the adjustment part of this utility model.

[0020] In the diagram: 1. High-level support frame; 2. High-level phosphoric acid storage tank; 3. Metering pump; 301. Input pipe; 302. Dropping output pipe; 4. Inert gas supply assembly; 401. Gas flow limiting pipeline; 402. Delivery connection pipe; 403. Inert gas source; 404. Valve; 5. Pressure transmitter assembly; 501. Press control valve; 502. Fixed cylinder; 503. Connecting pipe; 504. Moving piston; 505. Support guide plate; 506. Press contact plate; 507. Control spring; 508. Adjusting slider; 509. Adjusting screw; 510. First bevel gear; 511. Adjusting knob; 512. Second bevel gear; 513. Through hole; 6. Safety valve. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] Please see Figure 1 and Figure 2 As shown, a phosphoric acid dripping device for the preparation of tributyl phosphate includes a high-level support frame 1 and an inert gas supply assembly 4. A high-level phosphoric acid storage tank 2 is fixedly installed at the top of the high-level support frame 1. A metering pump 3 is fixedly connected to the bottom of the high-level phosphoric acid storage tank 2. One end of an input pipe 301 is fixedly connected to the input end of the metering pump 3. The other end of the input pipe 301 is fixedly connected to the bottom of the inner cavity of the high-level phosphoric acid storage tank 2. A dripping output pipe 302 is fixedly connected to the output end of the metering pump 3. The metering pump 3 is used to deliver phosphoric acid in the high-level phosphoric acid storage tank 2 to the esterification reactor at a precise and controllable flow rate.

[0023] The interior of the high-level phosphoric acid storage tank 2 is filled with high-concentration phosphoric acid to be added dropwise.

[0024] In order to provide a stable inlet pressure for the metering pump 3 and prevent cavitation, the high-level phosphoric acid storage tank 2 is fixedly installed at the top of the high-level support frame 1. The high-level support frame 1 is used to stably support the high-level phosphoric acid storage tank 2 and its auxiliary components, and to ensure that there is a sufficient height difference between it and the reaction vessel below.

[0025] By applying a stable inert gas back pressure to the high-level phosphoric acid storage tank 2, a constant inlet pressure is provided for the downstream metering pump 3, thereby avoiding the problem of reduced static head caused by the drop in liquid level in the high-level phosphoric acid storage tank 2, ensuring the stability of the inlet conditions of the metering pump 3 during operation, and thus improving the accuracy of dripping.

[0026] Meanwhile, the inert gas covering the surface of the phosphoric acid solution effectively isolates it from the air, preventing the phosphoric acid from absorbing moisture and becoming diluted, and also avoiding possible oxidation reactions, thus ensuring the accuracy of the concentration of the materials participating in the reaction.

[0027] The inert gas supply assembly 4 includes an inert gas source 403, a delivery connecting pipe 402, and a gas flow limiting pipe 401. The inert gas source 403 is fixedly connected to one end of the delivery connecting pipe 402, and the other end of the delivery connecting pipe 402 is fixedly connected to the gas flow limiting pipe 401. The gas flow limiting pipe 401 is fixedly connected to the upper end of the inner cavity of the high-level phosphoric acid storage tank 2. A pressure transmitter assembly 5 is also provided between the high-level phosphoric acid storage tank 2 and the gas flow limiting pipeline 401. The pressure transmitter assembly 5 includes a press control valve 501 and a movable press contact plate 506. The press contact plate 506 is used to directly press or release the valve core of the press control valve 501 under the drive of the pressure transmitter assembly 5, thereby controlling the opening and closing of the gas flow limiting pipeline 401.

[0028] To address the technical problem of inaccurate metering pump flow caused by pressure fluctuations in conventional dripping equipment when adding phosphoric acid, due to the volatility, corrosiveness, and viscosity variation with concentration of phosphoric acid, this application designs a dripping device with pressure stabilization function. By setting the pressure transmitter component 5, it can automatically maintain a constant pressure inside the tank, and it does not require external power or compressed air drive. It has a simple structure, is easy to maintain, and is particularly suitable for use in the synthesis process of tributyl phosphate.

[0029] For a specific example, please refer to Figure 2 and Figure 3 As shown, a valve 404 is also installed at the delivery connection pipe 402. This valve 404 is a manual ball valve or a shut-off valve, used to manually cut off the gas supply when the equipment is under maintenance or shut down for a long period of time. The inert gas source 403 is a high-pressure nitrogen cylinder or a nitrogen pipeline network in the plant area. By providing a chemically stable inert gas, it is used to maintain pressure on the one hand, and to prevent phosphoric acid from being oxidized or absorbing moisture by contact with air on the other hand.

[0030] As a further embodiment, see [reference]. Figure 4 As shown, the press control valve 501 is fixedly installed on the gas flow limiting pipeline 401. Specifically, the press control valve 501 is a normally closed mechanical valve, such as a push-rod type pneumatic valve. The gas flow limiting pipeline 401 is a section of stainless steel pipe, which plays a certain role in throttling and buffering. Pressing the contact plate 506 to actuate the valve core of the press control valve 501 opens the valve. After release, the press control valve 501 automatically closes under the action of the internal spring, realizing the on / off control function of nitrogen supply.

[0031] For further details, please refer to [link / reference]. Figure 4 and Figure 5 As shown, the pressure transmitter assembly 5 also includes a fixed cylinder 502 and a movable piston 504. The fixed cylinder 502 is fixedly installed on the upper surface of the high-level phosphoric acid storage tank 2. The movable piston 504 is slidably connected in the inner cavity of the fixed cylinder 502. The movable piston 504 is used to sense the pressure change in the high-level phosphoric acid storage tank 2 and convert the pressure signal into linear displacement, thereby driving the pressing contact plate 506 to move. Through this technical solution, the pressure change is converted into mechanical motion, providing a power source for control.

[0032] Furthermore, in order to ensure that the pressure between the fixed cylinder 502 and the inner cavity of the high-level phosphoric acid storage tank 2 remains equal in real time, and to ensure that the moving piston 504 can accurately sense the pressure inside the tank, one end of the connecting pipe 503 is fixedly connected to the bottom of the inner cavity of the fixed cylinder 502, and the other end of the connecting pipe 503 extends into the inner cavity of the high-level phosphoric acid storage tank 2 and is fixedly connected to the high-level phosphoric acid storage tank 2. Through this technical solution, the accuracy and real-time performance of pressure sensing are ensured.

[0033] In a particular design of this embodiment, see [reference] Figure 5 As shown, the movable piston 504 drives the pressing contact plate 506 to move via the support guide plate 505. Specifically, the upper surface of the movable piston 504 is fixedly connected to both sides of the support guide plate 505. The top of the support guide plate 505 penetrates the upper wall of the inner cavity of the fixed cylinder 502 and extends to the outside of the wall. The tops of the two support guide plates 505 are fixedly connected to the bottom surface of the pressing contact plate 506. Through this technical solution, the linear motion of the movable piston 504 in the fixed cylinder 502 is effectively transmitted to the pressing contact plate 506 outside the fixed cylinder 502, thus realizing the power transmission function.

[0034] In a further optimized design of this embodiment, in order to ensure the sliding seal between the moving piston 504 and the fixed cylinder 502, prevent pressure leakage, and ensure response sensitivity, a sealing ring made of polytetrafluoroethylene (PTFE) or fluororubber is embedded in the annular groove of the moving piston 504. Through the tight contact between the sealing ring and the inner wall of the fixed cylinder 502, smooth sliding is ensured and dynamic sealing is achieved.

[0035] Furthermore, a control spring 507 is fixedly installed on the upper surface of the moving piston 504. This technical solution utilizes the downward elastic force of the control spring 507 to balance the upward gas pressure acting on the lower surface of the moving piston 504. When the addition of phosphoric acid causes a decrease in pressure inside the tank, the upward gas pressure is less than the downward spring force. Driven by the spring force, the moving piston 504 moves downward, thereby causing the pressing contact plate 506 to press down via the support guide plate 505, opening the pressing control valve 501 to replenish pressure. When the pressure rises back to the set value, the gas pressure and the elastic force of the control spring 507 are balanced again, the moving piston 504 moves upward, the pressing contact plate 506 is released, and the pressing control valve 501 closes.

[0036] To enable flexible adjustment of the system's set pressure to adapt to different process requirements, the control spring 507 is also equipped with an adjustment section, which includes an adjustment slider 508 and an adjustment screw 509. The adjustment slider 508 is disposed in the inner cavity of the fixed cylinder 502 and slides within the fixed cylinder 502. The top end of the control spring 507 abuts against the lower surface of the adjustment slider 508. The adjustment screw 509 is rotatably connected to the upper wall of the inner cavity of the fixed cylinder 502, and the adjustment screw 509 passes through the adjustment slider 508 and engages with the adjustment slider 509. The screw thread between 08 and the adjusting screw 509 can drive the adjusting slider 508 to move up and down, thereby changing the pre-compression of the control spring 507: raising the adjusting slider 508 increases the pre-tightening force of the control spring 507 and raises the set pressure; lowering the adjusting slider 508 lowers the set pressure. In order to ensure that the inside of the fixed cylinder 502 is in communication with the atmosphere during the adjustment process and to avoid the formation of negative or positive pressure affecting the movement of the moving piston 504, a through hole 513 communicating with the outside is provided on the upper side of the inner cavity of the fixed cylinder 502.

[0037] Furthermore, for easier adjustment, please refer to... Figure 6 As shown, a first bevel gear 510 is fixedly connected to the arc-shaped wall of the adjusting screw 509, and an adjusting knob 511 is rotatably connected to the outer wall of the fixed cylinder 502. One end of the adjusting knob 511 extends into the inner cavity of the fixed cylinder 502, and a second bevel gear 512 is fixedly connected to the other end of the adjusting knob 511. The second bevel gear 512 meshes with the first bevel gear 510. With this technical solution, the operator can directly rotate the adjusting knob 511 outside the fixed cylinder 502, converting the horizontal rotational motion into the vertical rotational motion of the adjusting screw 509 through the bevel gear pair, thereby achieving the adjustment of the set pressure. The operation is safe and convenient.

[0038] As another aspect of this application, in order to ensure the safety of the dripping device under extreme conditions and to prevent danger caused by excessive pressure in the high-level phosphoric acid storage tank 2 due to reasons such as failure of the pressure transmitter component 5 or accidental opening of valve 404, a safety valve 6 is installed on the top of the high-level phosphoric acid storage tank 2. The safety valve 6 is fixedly installed on the top wall of the high-level phosphoric acid storage tank 2 and is directly connected to the inner cavity of the high-level phosphoric acid storage tank 2. In a preferred embodiment, the opening pressure of the safety valve 6 is set to be slightly higher than the upper limit of the normal operating pressure of the pressure transmitter component 5, but absolutely lower than the design pressure of the high-level phosphoric acid storage tank 2. For example, if the set pressure of the pressure transmitter component 5 is 0.1 MPa, the set pressure of the safety valve 6 can be set to 0.12-0.15 MPa. The above-mentioned gradient pressure setting ensures that the pressure regulation of this device is mainly based on the mechanical pressure transmitter component 5, and the safety valve 6 is only used as the final safety guarantee.

[0039] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A phosphoric acid dropping device for the preparation of tributyl phosphate, comprising a high-level support frame (1) and an inert gas supply assembly (4), characterized in that: A high-level phosphoric acid storage tank (2) is fixedly installed at the top of the high-level support frame (1). A metering pump (3) is fixedly connected to the bottom of the high-level phosphoric acid storage tank (2). One end of an input pipe (301) is fixedly connected to the input end of the metering pump (3). The other end of the input pipe (301) is fixedly connected to the bottom of the inner cavity of the high-level phosphoric acid storage tank (2). A dripping output pipe (302) is fixedly connected to the output end of the metering pump (3). The inert gas supply assembly (4) includes an inert gas source (403), a delivery connection pipe (402), and a gas flow restriction pipe (401). The inert gas source (403) is fixedly connected to one end of the delivery connection pipe (402), and the other end of the delivery connection pipe (402) is fixedly connected to the gas flow restriction pipe (401). The gas flow restriction pipe (401) is fixedly connected to the upper end of the inner cavity of the high-level phosphoric acid storage tank (2). A pressure transmitter assembly (5) is also provided between the high-level phosphoric acid storage tank (2) and the gas flow limiting pipeline (401). The pressure transmitter assembly (5) includes a press control valve (501) and a movable press contact plate (506). The press contact plate (506) is used to directly press or release the valve core of the press control valve (501) under the drive of the pressure transmitter assembly (5), thereby controlling the opening and closing of the gas flow limiting pipeline (401).

2. The phosphoric acid dropping device for the preparation of tributyl phosphate according to claim 1, characterized in that: A valve (404) is also installed at the conveying connection pipe (402).

3. The phosphoric acid dropping device for the preparation of tributyl phosphate according to claim 1, characterized in that: The press control valve (501) is fixedly installed on the gas flow limiting pipeline (401), and the press control valve (501) is a normally closed mechanical valve.

4. The phosphoric acid dropping device for the preparation of tributyl phosphate according to claim 1, characterized in that: The pressure transmitter assembly (5) also includes a fixed cylinder (502) and a movable piston (504). The fixed cylinder (502) is fixedly installed on the upper surface of the high-level phosphoric acid storage tank (2). The movable piston (504) is slidably connected in the inner cavity of the fixed cylinder (502). The top of the high-level phosphoric acid storage tank (2) is also provided with a safety valve (6), which is directly connected to the inner cavity of the high-level phosphoric acid storage tank (2).

5. The phosphoric acid dropping device for the preparation of tributyl phosphate according to claim 4, characterized in that: The bottom of the inner cavity of the fixed cylinder (502) is fixedly connected to one end of a connecting pipe (503), and the other end of the connecting pipe (503) extends into the inner cavity of the high-level phosphoric acid storage tank (2) and is fixedly connected to the high-level phosphoric acid storage tank (2).

6. The phosphoric acid dropping apparatus for the preparation of tributyl phosphate according to claim 5, characterized in that: The upper surface of the movable piston (504) is fixedly connected to both sides of the support guide plate (505). The top of the support guide plate (505) penetrates the upper wall of the inner cavity of the fixed cylinder (502) and extends to the outside of the wall. The tops of the two support guide plates (505) are fixedly connected to the bottom surface of the pressing contact plate (506).

7. The phosphoric acid dropping device for the preparation of tributyl phosphate according to claim 6, characterized in that: A control spring (507) is fixedly installed on the upper surface of the movable piston (504).

8. The phosphoric acid dropping apparatus for the preparation of tributyl phosphate according to claim 7, characterized in that: The control spring (507) is also provided with an adjustment part, which includes an adjustment slider (508) and an adjustment screw (509). The adjustment slider (508) is disposed in the inner cavity of the fixed cylinder (502) and is slidably engaged with the fixed cylinder (502). The adjustment screw (509) is rotatably connected to the upper wall of the inner cavity of the fixed cylinder (502). The adjustment screw (509) passes through the adjustment slider (508) and is threadedly engaged with the adjustment slider (508). A through hole (513) communicating with the outside is provided on the upper side of the inner cavity of the fixed cylinder (502).

9. The phosphoric acid dropping apparatus for the preparation of tributyl phosphate according to claim 8, characterized in that: The top end of the control spring (507) abuts against the lower surface of the adjusting slider (508).

10. The phosphoric acid dropping apparatus for the preparation of tributyl phosphate according to claim 8, characterized in that: A first bevel gear (510) is fixedly connected to the arc-shaped wall of the adjusting screw (509), and an adjusting knob (511) is rotatably connected to the outer wall of the fixed cylinder (502). One end of the adjusting knob (511) extends into the inner cavity of the fixed cylinder (502), and a second bevel gear (512) is fixedly connected to one end of the adjusting knob (511). The second bevel gear (512) meshes with the first bevel gear (510).

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