Solid-liquid neutralizing and drying integrated high-density anhydrous dipotassium phosphate production device

Abstract

The utility model discloses a solid-liquid neutralizing and drying integrated high-density anhydrous dipotassium phosphate production device, which relates to the technical field of chemical product production and comprises a mixing dryer, a solid potassium hydroxide feeding system and a liquid phosphoric acid feeding system. And various costs are obviously reduced. The density of the product is increased to 1.62 g / cm < 2 > and is increased by 116% compared with the traditional density, so that the occupied packaging and transportation space is effectively reduced, and the logistics cost is reduced; due to the unique solid-liquid reaction and drying process, the drying energy consumption is reduced to 180 kWh / t and is reduced by 72.3% compared with the traditional 650 kWh / t; the production process is automatically executed under the control of the PLC, so that the manual intervention is reduced, the labor cost is reduced by 60%, the cost is greatly reduced in all directions, the production device ingeniously integrates the functions of neutralization reaction, drying and cooling, and the production efficiency is greatly improved. In the drying stage, micro-negative pressure in the mixing dryer is maintained through an induced draft fan, and dust emission is strictly controlled to be smaller than or equal to 10 mg / m.

Description

Technical Field

[0001] This utility model relates to the field of chemical product production technology, and in particular to a high-density anhydrous dipotassium hydrogen phosphate production device that integrates solid-liquid neutralization and drying. Background Technology

[0002] In the field of chemical production, dipotassium hydrogen phosphate is an important chemical product with wide applications in many industries. It has diverse appearances, including colorless or white tetragonal coarse particles, colorless flaky or needle-like crystals, and white granular powder. It is easily soluble in water and has good stability in air, but it loses its water of crystallization at 400℃ to become metaphosphate. It decomposes upon melting and transforms into potassium pyrophosphate upon ignition.

[0003] Currently, the industry commonly uses the solution neutralization method to produce dipotassium hydrogen phosphate. The specific process is as follows: First, solid potassium hydroxide is prepared into a 30% aqueous solution. After clarification and filtration to remove impurities, it is added to a corrosion-resistant reaction vessel. While stirring, an appropriate amount of 50% phosphoric acid solution is slowly added, and a neutralization reaction is carried out at 90-100℃, with the final pH value strictly controlled between 8.5 and 9.0. Subsequently, the solution is heated to 120-124℃ for concentration, followed by filtration to remove insoluble matter. The clarified filtrate is cooled to below 20℃ to precipitate crystals, which are then separated by centrifugation and air-dried to finally obtain the finished dipotassium hydrogen phosphate product.

[0004] However, existing technologies have many problems that urgently need to be solved:

[0005] Product density and cost issues: Existing technology uses a spray dryer to dry the neutralized liquid reaction solution, resulting in anhydrous dipotassium hydrogen phosphate with low density. This not only leads to a large space requirement during packaging, increasing packaging costs, but also significantly increases logistics costs due to the increased space occupied.

[0006] Energy consumption cost issue: When liquid potassium hydroxide and liquid phosphoric acid are used as raw materials for neutralization reaction, a large amount of water is used as solvent, which leads to the need to evaporate a large amount of water during the subsequent drying process, resulting in extremely high drying energy consumption and greatly increasing production costs.

[0007] Equipment and process issues: Existing production technology and equipment have relatively limited functions, with neutralization reactions and drying requiring different equipment, resulting in significant equipment investment. Furthermore, the multiple production stages make the process cumbersome, require a large production area, increase manual operation steps, and consequently raise labor costs.

[0008] In summary, existing dipotassium hydrogen phosphate production technologies have many shortcomings in terms of product characteristics, energy consumption, equipment, and cost. There is an urgent need for an innovative production technology to solve these problems, improve production efficiency, reduce costs, and enhance product quality. This utility model was developed based on this background. Utility Model Content

[0009] To address the shortcomings of existing technologies, this invention provides a high-density anhydrous dipotassium hydrogen phosphate production device that integrates solid-liquid neutralization and drying, solving many technical problems in traditional dipotassium hydrogen phosphate production technology in terms of product characteristics, energy consumption, equipment, and cost.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying includes:

[0012] Mixing dryer: It is equipped with an internal stirring device, which includes a motor. The outer wall of the mixing dryer is equipped with a jacket, which includes a steam inlet, a condensate outlet, a condensate inlet, and a steam outlet. A discharge port is provided at the bottom.

[0013] Solid potassium hydroxide feeding system: including solid potassium hydroxide storage tank, storage tank electronic scale, and conveyor, one end of the conveyor is connected to the storage tank, and the other end is connected to the top of the mixing dryer;

[0014] Liquid phosphoric acid feeding system: includes phosphoric acid storage tank, phosphoric acid scale, and precision filter. The filter outlet extends into the upper part of the mixing dryer through a pipe, and a drip nozzle is installed at the end of the pipe.

[0015] The top of the mixing dryer is connected to an induced draft fan for the discharge of water vapor during the drying stage; the device achieves the integration of the entire process of neutralization reaction (90-100℃), drying (120-150℃), and cooling (30-40℃) through jacket temperature switching (steam / cooling water) and stirring speed control (70-100r / min).

[0016] Preferably, the jacket of the mixing dryer has a double-layer spiral channel structure, which integrates the functions of steam heating (90-100℃) in the neutralization stage, high-temperature steam (120-150℃) in the drying stage, and circulating water cooling in the cooling stage through valve switching.

[0017] Preferably, the liquid phosphoric acid feeding system has a flow regulating valve in the drip nozzle, which, in conjunction with the real-time weighing data of the phosphoric acid scale, controls the dripping time of phosphoric acid (503kg) to 1-1.5 hours, and the stirring speed is maintained at 70-100r / min during the dripping process to ensure the uniformity of the solid-liquid reaction and generate a paste-like intermediate product with a water content of ≤30%.

[0018] Preferably, in the drying stage, a slight negative pressure (-50 to -100 Pa) is maintained inside the mixing dryer by an induced draft fan, combined with jacket steam temperature (120-150℃) and stirring (70-100 r / min), to reduce the moisture content of the paste from ≤30% to ≤1%, with a drying time of 3-5 hours; in the cooling stage, the material temperature is rapidly reduced from 120-150℃ to 30-40℃ within 30-60 minutes by jacket cooling water (inlet 6).

[0019] Preferably, the solid potassium hydroxide storage tank electronic scale, phosphoric acid scale, motor, jacketed valve (steam / cooling water), and induced draft fan are all electrically connected to the PLC control system, and automatically execute the entire process through a preset program: solid feeding → phosphoric acid dripping → heat preservation reaction → heating and drying → cooling → discharging, reducing manual intervention.

[0020] Preferably, the effective internal volume of the mixing dryer is designed to be 1.5-2 times the reaction volume of solid potassium hydroxide (528kg) and phosphoric acid (503kg). The inner wall is equipped with a flow guide baffle, and the stirring paddle adopts a double spiral structure to ensure that the solid-liquid mixing uniformity is ≥95%, the final product density is ≥1.5g / cm³ (traditional spray-dried products are ≤0.8g / cm³), and the moisture content is ≤1%, which meets the GB / T2587-2023 standard for anhydrous dipotassium hydrogen phosphate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Cost Reduction: This utility model significantly reduces various costs thanks to its innovative production equipment and processes. By increasing the product density to 1.62 g / cm³, a 116% improvement over traditional methods, it effectively reduces packaging and transportation space requirements, thus lowering logistics costs. The unique solid-liquid reaction and drying process reduces drying energy consumption to 180 kWh / t, a 72.3% reduction compared to the traditional 650 kWh / t. Furthermore, PLC-controlled automated production processes reduce manual intervention, lowering labor costs by 60%, resulting in a comprehensive and substantial cost reduction.

[0023] 2. Increased Efficiency: This production unit ingeniously integrates neutralization reaction, drying, and cooling functions, greatly improving production efficiency. The production cycle for a single batch has been drastically reduced from 15 hours in the traditional multi-equipment series to 7.5 hours, a 50% reduction. This optimization makes the production process more compact and efficient, enabling the production of more products in the same amount of time to meet market demand.

[0024] 3. Quality Improvement: This utility model has achieved remarkable results in terms of product quality. The anhydrous dipotassium hydrogen phosphate produced has a moisture content of only 0.8%, which fully meets and exceeds the national standard requirements. The product compliance rate reaches 100%, effectively avoiding the cumbersome secondary drying process, ensuring the stability and reliability of product quality, and giving the product a competitive advantage in the market.

[0025] 4. Green and Environmentally Friendly: This utility model places great emphasis on environmental performance. During the drying stage, a slight negative pressure is maintained inside the mixing dryer by an induced draft fan, strictly controlling dust emissions to ≤10mg / m³, which is better than the national standard of 15mg / m³. This greatly reduces environmental pollution during the production process, conforms to the current trend of green production, and lays the foundation for the sustainable development of enterprises.

[0026] 5. Equipment and Process Advantages: From the perspective of equipment and process, this utility model has outstanding highlights. The jacket adopts a double-layer spiral channel structure, and the advanced temperature switching technology can efficiently meet the temperature requirements of different production stages. For example, in the cooling stage, the temperature can be reduced by 100°C within 30 minutes. The design of the double spiral ribbon agitator and guide baffle, as well as the rotating drip nozzle, ensures a solid-liquid mixing uniformity of 97% and minimal pH fluctuation. At the same time, the comprehensive fault response mechanism, such as automatic backflushing when the dripping pipeline is blocked and agitator overload protection, comprehensively ensures efficient and stable production operation, providing strong support for the green production of high-density anhydrous dipotassium hydrogen phosphate. Attached Figure Description

[0027] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the structure of this utility model.

[0029] Legend: 1. Phosphoric acid storage tank; 2. Phosphoric acid scale; 3. Motor; 4. Steam inlet; 5. Condensate outlet; 6. Condensate inlet; 7. Steam outlet; 8. Conveyor; 9. Solid potassium hydroxide storage tank; 10. Solid potassium hydroxide storage tank electronic scale; 11. Precision filter; 12. Mixing dryer; 13. Exhaust fan. Detailed Implementation

[0030] This application provides a high-density anhydrous dipotassium hydrogen phosphate production device that integrates solid-liquid neutralization and drying, effectively solving many technical problems existing in traditional dipotassium hydrogen phosphate production technology in terms of product characteristics, energy consumption, equipment and cost.

[0031] Example

[0032] like Figure 1 As shown, the overall technical solution in this application embodiment is as follows:

[0033] To address the problems existing in the prior art, this utility model provides a high-density anhydrous dipotassium hydrogen phosphate production device integrating solid-liquid neutralization and drying, comprising:

[0034] Mixing dryer 12: It is equipped with an internal stirring device, which includes a motor 3. The outer wall of the mixing dryer 12 is equipped with a jacket, which includes a steam inlet 4, a condensate outlet 5, a condensate inlet 6, and a steam outlet 7. A discharge port is provided at the bottom.

[0035] Solid potassium hydroxide feeding system: includes a solid potassium hydroxide storage tank 9, a solid potassium hydroxide storage tank electronic scale 10, and a conveyor 8. One end of the conveyor 8 is connected to the solid potassium hydroxide storage tank 9, and the other end is connected to the top of the mixing dryer 12.

[0036] Liquid phosphoric acid feeding system: includes phosphoric acid storage tank 1, phosphoric acid weigher 2, and precision filter 11. The outlet of the precision filter 11 extends into the upper part of the mixing dryer 12 through a pipe, and a drip nozzle is provided at the end of the pipe.

[0037] The top of the mixing dryer 12 is connected to an induced draft fan 13.

[0038] The inner wall of the mixing dryer 12 is made of 316L stainless steel (resistant to phosphoric acid corrosion), with a thickness of 8mm and an internal volume of 3m³, corresponding to 1.8 times the reaction volume of 528kgKOH + 503kgphosphoric acid.

[0039] Jacket system: Double-layer spiral channel (lower layer steam / condensate, upper layer cooling water), steam inlet 4 connects to a 0.6MPa saturated steam source, and condensate inlet 6 connects to the circulating water system (water temperature 15-20℃).

[0040] Stirring device: 3 motors with a power of 15kW, double-ribbon stirring paddle (outer diameter Φ800mm, pitch 300mm), the speed is adjustable from 70-100r / min by frequency converter, and four sets of guide baffles (height 50mm) are set on the inner wall to improve the uniformity of solid-liquid mixing.

[0041] Inlet and outlet design: The top is equipped with a solid feed inlet (connected to conveyor 8) and a phosphoric acid dripping pipe (with precision filter 11), the bottom discharge port is equipped with a pneumatic ball valve (DN150), the top is equipped with an induced draft fan interface 13, and a built-in temperature sensor (accuracy ±1℃).

[0042] The solid potassium hydroxide feeding system has a solid potassium hydroxide storage tank 9 with a capacity of 1000kg and a vibrating feeder at the bottom. The solid potassium hydroxide storage tank electronic scale 10 has an accuracy of ±0.1kg. The conveyor 8 is a screw conveyor (conveying capacity 200kg / h). The pipeline is lined with polytetrafluoroethylene for corrosion protection.

[0043] Liquid phosphoric acid feeding system: Phosphoric acid storage tank 1 with a capacity of 1000L, equipped with a gear pump (flow rate 50L / h), phosphoric acid scale 2 is a weighing module (accuracy ±0.1kg), precision filter 11 with a pore size of 50μm, and a 360° rotating nozzle (pore size 2mm, pressure 0.2MPa) at the end of the dripping pipe.

[0044] Automation control: PLC system (Siemens S7-1200) integration: Real-time data acquisition of electronic scale 10 for solid potassium hydroxide storage tank and scale 2 for phosphoric acid, automatic switching of jacket valve (steam / cooling water), linkage control of stirring speed and induced draft fan 13, and preset five-stage process program (feeding → dripping → heat preservation → drying → cooling).

[0045] Full production process:

[0046] 1. Solid-liquid neutralization reaction (90-100℃, 1-2h):

[0047] Feeding: Solid KOH (528kg) is fed into the mixing dryer 12 via conveyor 8 within ten minutes, and stirring is started (80r / min).

[0048] Add phosphoric acid: Phosphoric acid (503 kg, concentration 85%) is added dropwise through a precision filter 11 at a rate of 50 L / h (takes 1.2 hours). The dropper nozzle is 200 mm away from the material surface to avoid splashing.

[0049] Insulation reaction: 0.3MPa steam (95℃) is introduced into the jacket to maintain pH=8.8 (monitored by an online pH meter). The reaction produces a paste (28% water content, 1.2g / cm³ density).

[0050] 2. Integrated drying (120-150℃, 4h):

[0051] Heating stage: Steam pressure rises to 0.5MPa (jacket temperature 135℃), induced draft fan 13 is turned on (air volume 1500m³ / h, maintaining -80Pa slight negative pressure), stirring speed is increased to 100r / min, and the material is in a tumbling state;

[0052] Moisture control: Samples are taken every 30 minutes. After 3 hours, the moisture content drops to 1.2%. Continue drying for another hour until it reaches ≤1% (monitored online by an infrared moisture meter).

[0053] 3. Rapid cooling (30-60 min):

[0054] Close the steam valve, switch the jacket to cooling water (15℃), maintain stirring at 70r / min, and reduce the material temperature to 35℃ within 30 minutes (to avoid high-temperature agglomeration).

[0055] Feeding: The pneumatic ball valve is opened, and the material is directly fed into the packaging machine (25kg / bag, lined with PE film) through the screw conveyor.

[0056] Implementation results:

[0057]

[0058] Jacket temperature switching technology:

[0059] Neutralization stage: The lower steam channel (95℃) and the upper cooling water bypass are closed to prevent the paste from overheating and solidifying;

[0060] Drying stage: Double-layer steam channels are fully open (135℃), and spiral channels enhance heat exchange efficiency;

[0061] Cooling stage: The upper layer of cooling water (15℃) flows in the opposite direction, and the temperature drops by 100℃ in 30 minutes, which is better than traditional natural cooling (2 hours).

[0062] Solid-liquid mixing homogeneity design:

[0063] With the addition of a double-ribbon agitator and a flow guide baffle, the mixing uniformity of solid KOH particles with a diameter ≤3mm reaches 97% within ten minutes (as measured by a laser particle size analyzer).

[0064] The rotating design of the phosphoric acid dispensing nozzle avoids localized acid overload that could cause pH fluctuations (measured pH fluctuation ≤ ±0.1).

[0065] Micro-negative pressure drying prevents dust:

[0066] With an induced draft fan and a matching stirring speed, dust emissions during the drying stage are ≤10mg / m³ (national standard 15mg / m³), meeting green requirements.

[0067] Troubleshooting:

[0068] Clogged dripping pipe: Differential pressure sensors are installed before and after the precision filter 11. When the pressure is ≥0.1MPa, it will automatically backflush (compressed air source).

[0069] Overload protection for stirring: Motor 3 is equipped with torque protection, automatically reducing speed when exceeding 120% of rated torque, while cooling water is circulated through the jacket to prevent material solidification. Through equipment integration (neutralization-drying-cooling in one unit), precise control of process parameters (dropping speed, temperature gradient, stirring speed), and automated linkage (PLC full-process control), the green production of high-density anhydrous dipotassium hydrogen phosphate has been achieved, breaking through the bottleneck of "high water consumption, high energy consumption, and low density" of traditional solution methods. The annual production capacity of a single unit can reach 5,000 tons, and the overall cost is reduced by more than 35%, making it suitable for fertilizers, pharmaceuticals, food additives, and other fields.

[0070] Working principle: This device integrates solid-liquid reaction and drying functions through a mixing dryer 12. Solid potassium hydroxide is metered from the solid potassium hydroxide storage tank 9 by the solid potassium hydroxide storage tank electronic scale 10 and then fed into the mixing dryer 12 via the conveyor 8. Liquid phosphoric acid is added dropwise from the phosphoric acid storage tank 1 through the precision filter 11 (1-1.5h). The double-ribbon stirring (70-100r / min) ensures that the solid and liquid react fully at 90-100℃ maintained by the jacket, producing a paste (25-30% water content).

[0071] Switch to jacketed steam (120-150℃) and turn on the induced draft fan at 13 micro negative pressure for drying. Stir and toss to form dense granules (density 1.62g / cm³) with a moisture content ≤1%.

[0072] The temperature drops to 35°C in 30 minutes, and the material is discharged through the bottom discharge port. The entire process is linked by PLC to the solid potassium hydroxide storage tank electronic scale 10, phosphoric acid scale 2 and valves (steam inlet 4, condensate outlet 5, condensate inlet 6), realizing the integration of neutralization-drying-cooling. Compared with traditional spray drying (density 0.75g / cm³), the logistics cost is reduced by 55%, and the energy consumption is only 180kWh / t (saving 70%).

[0073] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying, characterized in that, include: Mixing dryer (12): It is equipped with a stirring device inside, which includes a motor (3). The outer wall of the mixing dryer (12) is equipped with a jacket, which includes a steam inlet (4), a condensate outlet (5), a condensate inlet (6), a steam outlet (7), and a discharge port at the bottom. Solid potassium hydroxide feeding system: includes a solid potassium hydroxide storage tank (9), a storage tank electronic scale (10), and a conveyor (8). One end of the conveyor (8) is connected to the storage tank (9), and the other end is connected to the top of the mixing dryer (12). Liquid phosphoric acid feeding system: includes phosphoric acid storage tank (1), phosphoric acid weigher (2), and precision filter (11). The outlet of the filter (11) extends into the upper part of the mixing dryer (12) through a pipe, and a drip nozzle is provided at the end of the pipe. The top of the mixing dryer (12) is connected to an induced draft fan (13).

2. The high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying as described in claim 1, characterized in that: The jacket of the mixing dryer (12) has a double-layer spiral channel structure.

3. The high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying as described in claim 1, characterized in that: The liquid phosphoric acid feeding system has a flow regulating valve in the drip nozzle, which is used in conjunction with the phosphoric acid weigher (2) to measure real-time weighing data.

4. The high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying as described in claim 1, characterized in that: The blower (13) maintains a slight negative pressure inside the mixing dryer (12).

5. The high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying as described in claim 1, characterized in that: The solid potassium hydroxide storage tank electronic scale (10), phosphoric acid scale (2), motor (3), jacketed valve, and induced draft fan (13) are all electrically connected to the PLC control system and are automatically executed through a preset program.

6. The high-density anhydrous dipotassium hydrogen phosphate production apparatus integrating solid-liquid neutralization and drying as described in claim 1, characterized in that: The effective internal volume of the mixing dryer (12) is designed to be 1.5-2 times the reaction volume of solid potassium hydroxide and phosphoric acid. The inner wall is equipped with a flow guide baffle, and the stirring paddle adopts a double spiral structure.

Images