DAP production device
By introducing a pre-neutralization tank, reactor, and ammonia adder into the DAP production unit, and combining the design of multiple ammonia adder pipes, the problem of insufficient amino acid reaction was solved, the yield and product quality were improved, and energy saving and emission reduction were achieved.
Patent Information
- Application Number
- CN202422980750.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-12-04
AI Technical Summary
In the current DAP production process, the amino acid reaction is insufficient, resulting in poor granulation effect and low yield.
A combination device consisting of a pre-neutralization tank, a reactor, and an ammonia adder is used. By setting multiple ammonia addition pipes in the granulator, the amount of ammonia added is increased, and the ammonia reacts with the ammonia gas in the material bed to regulate the amino acid reaction and make it more complete.
It improved the yield of DAP produced by the granulator, achieved a more efficient amino acid reaction, reduced ammonia escape and energy consumption, and improved product quality.
Smart Images
Figure CN223556004U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a chemical industry field, especially a DAP production device. BACKGROUND
[0002] DAP (diammonium hydrogen phosphate) is the most widely used P fertilizer in the world, which is made of the two most common components in the fertilizer industry, and is widely used due to its relatively high nutrient content and excellent physical properties. Ammonium phosphate fertilizer was first used in the 1960s, and DAP soon became the most popular product in its category. It is generated by controlled reaction of phosphoric acid and ammonia into hot slurry, which is cooled, granulated and sieved.
[0003] There are several common DAP production devices and production methods in the prior art:
[0004] 1. Traditional slurry spraying granulation process, which has the characteristics of one-body machine of granulation and drying, short process, smooth surface of the produced particles, high hardness, no secondary ammonia supplement position, only production of 57% content DAP product, small amount of ammonia escape from tail gas, and low drying tail gas temperature of 60-70℃;
[0005] 2. Pre-neutralization tank drum ammoniation process, which has the characteristics that the tank type pre-neutralization tank is suitable for w (P2O5) 40%-45% phosphoric acid to obtain good flowability and facilitate pump delivery of the slurry, thus high energy consumption for product drying and large amount of returned material required for granulation; secondary ammonia addition in the granulator to achieve superior product (nitrogen content above 17%); drying machine outlet temperature reaches 90-100℃; and large ammonia escape from the granulator;
[0006] 3. Tube reactor drum ammoniation process, which has the characteristics that the reaction is completed in the tube reactor, the reaction slurry is directly sprayed on the material bed in the granulator, the tube reactor can be one or two, the reaction time is short, the reaction heat is large (reaction temperature is 130-150℃), the material moisture is quickly evaporated, the required return material ratio is small (less than 2) to meet the granulation needs, the drying load is small, secondary ammonia addition in the granulator to achieve superior product (nitrogen content above 17%), the drying machine outlet temperature reaches 80-90℃, the slurry moisture is small, the product appearance is not round, the produced material particles are relatively small, the dust removal equipment load is increased, and the reaction heat is large with more ammonia escape.
[0007] Both the pre-neutralization tank drum ammoniation process and the tube reactor drum ammoniation process have the problem of insufficient ammonia acid reaction of the slurry after entering the granulator, resulting in poor granulation effect and low yield. INVENTION CONTENTS
[0008] The utility model discloses a DAP production device which can further adjust the ammonolysis reaction in the DAP production process, improve the granulation effect and increase the yield of finished products.
[0009] The utility model solves the above technical problem through the following technical scheme:
[0010] A DAP production device, comprising a pre-neutralization tank, a granulator, a reactor and an ammonia feeder.
[0011] The outlet of the pre-neutralization tank is connected to the granulator, and the pre-neutralization tank is used for ammonolysis reaction of the first phosphoric acid and ammonia to generate a first slurry.
[0012] The outlet of the reactor is connected to the granulator, and the reactor is used for ammonolysis reaction of the second phosphoric acid and ammonia to generate a second slurry.
[0013] The ammonia feeder is connected to the granulator, and the ammonia, the first slurry and the second slurry in the ammonia feeder all enter the material bed of the granulator to react and form DAP.
[0014] In the present scheme, the pre-neutralization tank and the reactor are both used for ammonolysis reaction to generate a slurry; the above-mentioned slurry is further reacted with ammonia in the ammonia feeder in the granulator to further adjust the ammonolysis reaction, so that the ammonolysis reaction is more sufficient, and the yield of DAP produced by the granulator is improved.
[0015] Preferably, the ammonia feeder comprises a plurality of ammonia feeding pipes, and the plurality of ammonia feeding pipes enter the interior of the granulator from the head and / or tail of the granulator.
[0016] In the present scheme, the plurality of ammonia feeding pipes can increase the amount of ammonia added to the granulator; in addition, the plurality of ammonia feeding pipes enter the interior of the granulator from the head and / or tail of the granulator, which is beneficial to the reaction of the slurry at the head and tail of the granulator with the ammonia in the ammonia feeding pipes, further improves the yield of DAP produced by the granulator, and in addition, the contact points between the material bed and the ammonia increase, which is beneficial to sufficient mass transfer (mass transfer is the process of transferring substances from one place to another under the action of concentration difference, temperature difference, pressure difference, potential difference, etc.), rapid operation control and reduction of the influence of unqualified DAP at the tail on the production device.
[0017] Preferably, the plurality of ammonia feeding pipes are uniformly and spacedly arranged from the tail of the granulator to the head of the granulator.
[0018] In the present scheme, the ammonia feeding pipes are uniformly and spacedly arranged from the tail of the granulator to the head of the granulator, which is beneficial to the uniform and sufficient reaction of the slurry in the granulator with the ammonia in the ammonia feeding pipes, further improving the yield of DAP produced by the granulator.
[0019] Preferably, the ammonia feeding pipe comprises an inlet and an outlet, the inlet is located outside the granulator and is used for feeding ammonia gas, and the outlet is located inside the granulator and is inserted into the material bed.
[0020] In this scheme, the setting mode of the ammonia feeding pipe in the granulator is conducive to feeding ammonia gas into the granulator and directly and fully contacting the ammonia gas with the material bed, so as to more quickly and efficiently produce the material; in addition, the multiple ammonia feeding points can adjust the temperature and liquid phase amount of the material on the material bed to achieve the best granulation condition, that is, the multiple ammonia feeding points are conducive to improving the granulation effect.
[0021] Preferably, the DAP production device further comprises a slurry pump, and the slurry pump is used for pumping the first slurry into the material bed.
[0022] In this scheme, the setting of the slurry pump is conducive to quickly and uniformly spreading the first slurry in the material bed.
[0023] Preferably, the reactor comprises a reaction pipe, a first end of the reaction pipe is located outside the granulator and is used for introducing the second phosphoric acid to react with ammonia gas, and a second end of the reaction pipe is located inside the granulator and is used for conveying the second slurry to the material bed.
[0024] In this scheme, the setting mode of the reaction pipe is conducive to operating the ammonolysis reaction and conveying the second slurry to the material bed.
[0025] Preferably, the first phosphoric acid comprises 42% content of phosphorus pentoxide, and the second phosphoric acid comprises 52% content of phosphorus pentoxide.
[0026] In this scheme, the content of phosphorus pentoxide in the first phosphoric acid and the second phosphoric acid is conducive to improving the DAP granulation effect.
[0027] Preferably, the DAP production device further comprises a dryer, a cooler, a coating machine and a packaging machine.
[0028] The inlet of the dryer is communicated with the granulator and is used for drying the DAP from the granulator, the outlet of the dryer is communicated with the cooler, and the cooler, the coating machine and the packaging machine are sequentially connected.
[0029] In this scheme, the setting of the above dryer, cooler, coating machine and packaging machine further optimizes the DAP produced by the granulator to improve the quality of the DAP.
[0030] Preferably, the DAP production device further comprises an elevator, a return bin and a screening system, and the screening system comprises a flat screen and a finished product screen.
[0031] The flat screen, the cooler, the finished product screen and the coating machine are sequentially connected.
[0032] The elevator is connected with the dryer and is used for conveying the dried DAP to the flat screen, the flat screen is used for screening finished products and non-finished products of the DAP, the finished products enter the cooling machine, and the non-finished products enter the granulator through the return bin.
[0033] In the scheme, the setting of the elevator is beneficial to stably and quickly conveying the DAP to the flat screen for next operation, the setting of the screening system can discharge non-finished products not meeting the specifications in the DAP, and the setting of the return bin is beneficial to recycling the non-finished products as a buffer to provide the return material with stable flow for the granulator to continue producing the DAP.
[0034] The utility model also provides a DAP production method which uses the above DAP production device for production.
[0035] In the scheme, the DAP production method using the above DAP production device is beneficial to producing high-quality DAP.
[0036] The utility model discloses a positive progress effect lies in: the DAP production device pre neutralization tank, reactor all are used for taking place ammonia acid reaction, to produce slurry, the above-mentioned slurry is reacted with ammonia gas in ammonia adding device in the granulator, to further adjust the above-mentioned ammonia acid reaction, make the above-mentioned ammonia acid reaction more fully, improve the finished product rate of DAP production of granulator, the DAP production method has the same effect as above.
[0037] The utility model discloses a positive progress effect lies in: the DAP production device pre neutralization tank, reactor all are used for taking place ammonia acid reaction, to produce slurry, the above-mentioned slurry is reacted with ammonia gas in ammonia adding device in the granulator, to further adjust the above-mentioned ammonia acid reaction, make the above-mentioned ammonia acid reaction more fully, improve the finished product rate of DAP production of granulator, the DAP production method has the same effect as above. BRIEF DESCRIPTION OF DRAWINGS
[0038] Figure 1 It is the structure schematic diagram of DAP production device of an embodiment of the utility model.
[0039] Figure 2 It is the structure schematic diagram of DAP production device of an embodiment of the utility model. Figure 1
[0040] BRIEF DESCRIPTION OF DRAWINGS
[0041] DAP production device 100
[0042] Pre neutralization tank 110
[0043] Granulator 120
[0044] Material bed 121
[0045] Nose 122
[0046] Tail 123
[0047] Reaction tube 130
[0048] Ammonia addition tube 140
[0049] 150 slurry pump
[0050] Dryer 160
[0051] Cooler 170
[0052] 180 wrapping machine
[0053] 200 hoist
[0054] Return material bin 210
[0055] 220 flat screen
[0056] Finished product sieve 230
[0057] 240 return strip
[0058] Metering belt 250
[0059] Exhaust gas treatment system 260
[0060] Crusher 270
[0061] Dust removal system 280 Detailed Implementation
[0062] The present invention will be described more clearly and completely below with reference to the accompanying drawings, but this does not limit the scope of the present invention to the present invention.
[0063] like Figures 1 to 2 As shown, this embodiment provides a DAP production apparatus 100, which includes: a pre-neutralization tank 110, a granulator 120, a reactor, and an ammonia feeder; the outlet of the pre-neutralization tank 110 is connected to the granulator 120, and the pre-neutralization tank 110 is used for the reaction of a first phosphoric acid with ammonia to produce an amino acid to generate a first slurry; the outlet of the reactor is connected to the granulator 120, and the reactor is used for the reaction of a second phosphoric acid with ammonia to produce a second slurry; the ammonia feeder is connected to the granulator 120, and the ammonia, the first slurry, and the second slurry in the ammonia feeder all enter the bed 121 of the granulator 120 to react and form DAP.
[0064] In the embodiment, the pre-neutralization tank 110 and the reactor are both used for ammonia acid reaction to produce slurry; the slurry is further reacted with ammonia gas in the ammonia feeder in the granulator 120 to further adjust the ammonia acid reaction and improve the yield of DAP produced by the granulator 120.
[0065] It should be noted that DAP is granulated in the granulator 120 to form DAP, and the granulator 120 will form tail gas during operation, which will enter the tail gas treatment system 260 connected with the granulator 120 for treatment. The tail gas treatment system 260 is also connected with the pre-neutralization tank 110, and the tail gas produced by the ammonia acid reaction in the pre-neutralization tank 110 also enters the tail gas treatment system 260 for treatment. In addition, the neutralization degree of the first phosphoric acid and ammonia gas in the ammonia acid reaction is in the range of 1.35-1.55, and the neutralization degree of the second phosphoric acid and ammonia gas in the ammonia acid reaction is in the range of 1.6-1.7. The tail gas produced by the ammonia acid reaction of the first phosphoric acid and ammonia gas directly enters the tail gas treatment system 260, and the tail gas produced by the ammonia acid reaction of the second phosphoric acid and ammonia gas enters the tail gas treatment system 260 through the granulator 120.
[0066] Reference Figure 1 and Figure 2 It should be understood that the ammonia feeder includes a plurality of ammonia feeding pipes 140, and the plurality of ammonia feeding pipes 140 enter the interior of the granulator 120 from the head 122 and / or the tail 123 of the granulator 120.
[0067] In the embodiment, the plurality of ammonia feeding pipes 140 can increase the amount of ammonia added to the granulator 120. In addition, the plurality of ammonia feeding pipes 140 enter the interior of the granulator 120 from the head 122 and / or the tail 123 of the granulator 120, that is, the ammonia feeding pipe 140 can enter the interior of the granulator 120 from any position of the head 122 and / or the tail 123 of the granulator 120. Such a setting mode is beneficial to the reaction of the slurry in the head 122 and the tail 123 of the granulator 120 with the ammonia gas in the ammonia feeding pipe 140, further improving the yield of DAP produced by the granulator 120. In addition, the increase of the contact points between the bed 121 and the ammonia gas is beneficial to sufficient mass transfer (mass transfer is the process of transferring substances in the system from one place to another under the action of concentration difference, temperature difference, pressure difference, potential difference, etc.), rapid operation control, and reduction of the influence of unqualified DAP produced by the tail 123 on the production device.
[0068] It should be noted that the pipe diameter of the ammonia feeding pipe 140 entering the bed 121 at different positions in the interior of the granulator 120 is not easy to be too large, and the pipe head inserted into the bed 121 forms an included angle in the range of 30-45 degrees with the vertical direction.
[0069] Reference Figure 1 and Figure 2It should be understood that the plurality of ammonia feeding pipes 140 are evenly spaced from the tail end 123 of the granulator 120 to the head end 122 of the granulator 120. Here, "evenly arranged" means that the spacing between two adjacent ammonia feeding pipes 140 is the same.
[0070] In the present embodiment, the ammonia feeding pipes 140 are evenly spaced from the tail end 123 of the granulator 120 to the head end 122 of the granulator 120, which is conducive to the uniform and sufficient reaction of the slurry in the granulator 120 with the ammonia gas in the ammonia feeding pipes 140, further improving the yield of the DAP produced by the granulator 120.
[0071] It should be noted that in the present embodiment, the first ammonia feeding pipe 140 is arranged at a position 2.4 meters away from the tail end, the second ammonia feeding pipe 140 is arranged at a position 400 mm away from the first ammonia feeding pipe 140, and the last ammonia feeding pipe 140 is arranged at a position 2.6 meters away from the head end. The ammonia feeding pipe 140 is a seamless steel pipe with an outer diameter of 32 mm and a pipe wall thickness of 3.5 mm. In addition, the number of ammonia feeding pipes 140 can be adjusted according to the production scale of the required DAP.
[0072] Reference Figure 1 and Figure 2 It should be understood that the ammonia feeding pipe 140 includes an inlet and an outlet. The inlet is located outside the granulator 120 and is used to discharge ammonia gas. The outlet is located inside the granulator 120 and is inserted into the material bed 121.
[0073] In the present embodiment, the arrangement of the ammonia feeding pipe 140 in the granulator 120 is conducive to the discharge of ammonia gas into the granulator 120 and the direct and sufficient contact of ammonia gas with the material bed 121, which is more rapid and efficient in producing material. In addition, the plurality of ammonia feeding points can adjust the temperature and liquid phase of the material on the material bed 121 to achieve the best granulation conditions. That is, the multi-point ammonia feeding is conducive to improving the granulation effect.
[0074] It should be noted that the outlet of the pipe is flat and the gap width is 5-8 mm.
[0075] Reference Figure 1 and Figure 2 It should be understood that the DAP production device 100 further comprises a slurry pump 150, which is used to pump the first slurry into the material bed 121.
[0076] In the present embodiment, the arrangement of the slurry pump 150 is conducive to the rapid and uniform distribution of the first slurry in the material bed 121.
[0077] It should be noted that the slurry pump 150 is arranged between the pre-neutralization tank 110; in addition, the slurry pump 150 is only a preferred structure, and in other embodiments, other structures that can pump the slurry can also be selected.
[0078] refer to Figure 1 and Figure 2 It is understood that the reactor includes a reaction tube 130, the first end of which is located outside the granulator 120 and is used to introduce the second phosphoric acid to react with ammonia to produce amino acids; the second end of the reaction tube 130 is located inside the granulator 120 and is used to transport the second slurry to the bed 121.
[0079] In this embodiment, the arrangement of the reaction tube 130 is beneficial for operating the amino acid reaction and for conveying the second slurry to the bed 121.
[0080] It should be noted that multiple reaction tubes 130 can be set according to the required DAP production scale, and the ammonia in the reaction tube 130 does not originate from the aforementioned ammonia addition tube 140; in addition, the tail gas in the granulator 120 enters the tail gas treatment system 260 through the air duct for tail gas treatment.
[0081] refer to Figure 1 and Figure 2 It should be understood that the primary phosphoric acid contains 42% phosphorus pentoxide and the secondary phosphoric acid contains 52% phosphorus pentoxide.
[0082] In this embodiment, the phosphorus pentoxide content in the first and second phosphoric acids is beneficial to improving the DAP granulation effect.
[0083] refer to Figure 1 and Figure 2 It is understood that the DAP production unit 100 also includes a dryer 160, a cooler 170, a wrapping machine 180, and a packaging machine.
[0084] The inlet of the dryer 160 is connected to the granulator 120 and is used to dry the DAP from the granulator 120. The outlet of the dryer 160 is connected to the cooler 170. The cooler 170, the coating machine 180 and the packaging machine are connected in sequence.
[0085] In this embodiment, the dryer 160, cooler 170, coating machine 180 and packaging machine are configured to further optimize the DAP produced by the granulator 120, so as to improve the quality of DAP.
[0086] It should be noted that the dryer 160 is also connected to the hot air furnace. The DAP in the dryer 160 is dried in parallel with the hot air from the hot air furnace. The exhaust gas generated in the dryer 160 enters the exhaust gas treatment system 260 for treatment. When the moisture content of DAP is 3-4% and the temperature is 70-80℃, it enters the dryer 160 from the granulator 120.
[0087] refer to Figure 1 and Figure 2It should be understood that the DAP production device 100 further comprises an elevator 200, a return bin 210 and a screening system; the screening system comprises a flat screen 220 and a finished product screen 230.
[0088] The flat screen 220, the cooling machine 170, the finished product screen 230 and the coating machine 180 are sequentially connected.
[0089] The elevator 200 is connected with the drying machine 160 and is used to send the dried DAP to the flat screen 220, the flat screen 220 is used to screen out finished products and non-finished products of the DAP, the finished products enter the cooling machine 170; the finished product screen 230 is used to further screen the cooled finished products into the coating machine 180, and the non-finished products enter the granulator 120 through the return bin 210.
[0090] In the embodiment, the setting of the elevator 200 is conducive to the stable and rapid sending of the DAP to the flat screen 220 for the next operation; the setting of the screening system can discharge non-finished products that do not meet the specifications in the DAP; and the setting of the return bin 210 is conducive to the recycling of the non-finished products, as a buffer, to provide the granulator with return materials with stable flow for the continuous production of the DAP.
[0091] It should be noted that the flat screen 220 transports the large-particle DAP screened out to the crusher 270 for crushing, and then returns to the return bin 210 through the return belt 240, the tail gas generated in the crusher 270 enters the dust removal system 280, and the small particles directly return to the return bin 210 through the return belt 240; the return materials in the return bin 210 are measured by the metering belt 250 and then enter the granulator 120; in addition, the flat screen 220 is in communication with the cooling machine 170, the finished products (here, the finished products are DAP particles of standard size) screened out enter the cooling machine 170 for cooling, the temperature of the finished products is reduced to below 45°C, and the cooled finished products enter the finished product screen 230, the tail gas after cooling enters the dust removal system 280, and the finished product screen 230 screens out a small amount of powder (i.e. powder generated by mutual friction of the DAP in the above process and powder generated by collision of the DAP with the flat screen 220, the cooling machine 170 and the finished product screen 230) generated by the flat screen 220 transporting the DAP to the finished product screen 230, and the powder returns to the return bin 210 through the return belt 240.
[0092] As known, the reaction of ammonia and acid is mainly controlled by the mass transfer speed, as long as the two reactants can be rapidly mixed, the reaction can be immediately completed, and any method that can strengthen the mass transfer speed of ammonia and acid in the process can accelerate the progress of the neutralization reaction. The key of DAP production is to achieve the best granulation condition through a reasonable ammonia-acid reaction mode, which is convenient for operation and easy for production.
[0093] There are three granulation mechanisms in the drum ammoniation granulator, namely coating granulation, bonding granulation and self-granulation; in order to maintain the particle size balance in the granulator 120, it is generally desired that the material granulation is mainly coating granulation, supplemented by a proper proportion of self-granulation, and bonding granulation is avoided as much as possible, because the quality of bonding granulation is poor and the particle size is not easy to control. However, when the particle size in the granulator 120 has lost balance (such as too much fine powder, product particles are too small), appropriately increasing the proportion of bonding granulation can be used as a means to adjust the particle size balance in the granulator 120. From the perspective of particle size balance, all process control of granulation and drying is to change the relative proportion of the three granulation mechanisms by adjusting the process parameters that have an impact. The appropriate material bed 121 material temperature and liquid phase amount of the granulator 120 are the key process conditions for granulation.
[0094] The utility model revolves around the center of granulation, on the basis of combining a large number of ammonia acid reactions of pre-neutralization (PN) + pipe reverse (PR) mixed process, further adjusting ammonia acid reaction by using the way of multi-point ammonia addition instead of single-point ammonia addition, fine control is carried out to the two key control indexes of material bed 121 material temperature and liquid phase amount that affect the granulation process, while adjusting the neutralization degree, the material bed 121 material temperature and liquid phase amount are fine adjusted, the best control point that temperature and liquid phase amount are matched is controlled, and the adjusting method is convenient and flexible. Referring to Figure 2 The schematic position of the ammonia addition point in the granulator 120 of an embodiment of the utility model.
[0095] From Figure 2 It can be seen from the drawings that the machine head 122 of the granulator 120 and the machine tail 123 of the granulator 120 are both provided with an ammoniation addition point, and the ammoniation is added by multiple pipes. The number of material pipes added to the material bed is increased or decreased according to the production scale. Taking the practical results of a 200,000 tons / year DAP production line as an example, the first ammonia addition pipe is arranged at a position 2.4 meters away from the discharge port of the machine tail 123, the second ammonia addition pipe is arranged at a position 400mm away from the first ammonia addition pipe, and the last ammonia addition pipe is arranged at a position 2.6 meters away from the machine head 122. The ammonia addition pipe is a seamless steel pipe with an outer diameter of 32mm and a pipe wall thickness of 3.5mm. The pipe opening of the pipe inserted into the material bed 121 is flat, and the gap width is 5-8mm. The contact points of the material bed 121 and the ammonia are increased, which is beneficial to full mass transfer, rapid operation control and reduction of the influence of unqualified material at the machine tail 123 on the production system. The granulation effect is stable. The pipe diameter of the ammonia addition pipe is not too large, and the pipe head inserted into the material bed 121 forms an included angle of 30-45° with the vertical direction.
[0096] The pre-neutralization (PN) + pipe reactor (PR) ammonia reaction process has been applied in multiple production lines. Compared with the pre-neutralization process (PN), this process has the characteristics of reducing the amount of returned material and maximizing the use of reaction heat. Compared with the pipe reactor process, it has the characteristics of reducing the slurry temperature and reducing ammonia escape. Currently, this process can achieve the range of two granulation indicators, that is, it can achieve the material temperature required for granulation in the range of 70-90°C and the liquid phase content in the range of 6-9%. However, in operation, the material temperature and liquid phase amount need to be adjusted at any time to reach the optimal control point. The pre-neutralization + pipe reactor mixed process is not flexible in adjusting the optimal points of material temperature and liquid phase amount at any time. After fine tuning, the effect is slow to reflect. If the adjustment is slightly large, it will appear a large fluctuation in the granulation layer, which is not conducive to stable production. If the granulator 120 does not have a multi-point ammonia addition process, when the material bed 121 of the granulator 120 changes, the site cannot adjust the material conditions in the granulator 120 in the first time. The unqualified material in the entire granulator 120 enters the drying process, and the subsequent system is disorderly. If the material is mostly powder, it will increase the load of the screening process, and the finished product screen area will be mixed with fine powder and small particles. The drying tail gas will also carry a large amount of dust, increasing the load and possibly causing the system to shut down. If the material is mostly large particles, the crushing capacity of the crusher will increase, and when it exceeds the crushing capacity, the crusher will stop working, causing the system to be blocked.
[0097] The DAP production device of the present embodiment adopts a multi-ammonia addition process. Ammonia is added at the head 122 of the granulator 120 for ammoniation, and ammonia is also added at the tail 123 of the granulator 120 for ammoniation, achieving uniform ammoniation of each part of the material bed 121 of the granulator 120. The granulator 120 with a reactor process is fine-tuned, and the material bed 121 of the granulator 120 is kept in the best granulation state at all times. The purpose is to keep the material outlet of the granulator 120 to meet the requirements that the particle size is greater than 4mm and not more than 5%, and the particle size is less than 2mm and not more than 10%.
[0098] By observing the material conditions of the granulator 120 at any time, when the particles in the granulator 120 are small, or the specific surface area of DAP is large, and the temperature of the material bed 121 is close to the upper limit of 90°C, it indicates that the temperature is high, the moisture evaporates quickly, and there is no fine powder on the surface of the particles. At this time, the amount of ammonia added should be appropriately reduced, the reaction temperature should be slightly reduced, and the moisture evaporation should be reduced. When the particles are small and the temperature of the material bed 121 is close to the lower limit of 70°C, it indicates that the temperature is low and the liquid phase amount is insufficient. At this time, the amount of ammonia added should be increased, the temperature of the material bed 121 should be increased through reaction, and the liquid phase amount should be increased.
[0099] The factors affecting the particle size balance in the granulator 120 are many, and the regulation is relatively complex. The particle size control is generally not a single factor adjustment but a multi-factor adjustment. The DAP production device of the embodiment adds a regulation method to the granulation by the process of the multiple ammonia adding pipes 140 on the basis of the pre-neutralization tank 110 and the reactor, has the characteristics of flexible regulation and quick effect. The multiple ammonia adding pipes 140 are used to fine-tune the granulation state, so as to achieve a more reasonable granulation effect. The following key steps need to be followed:
[0100] A: The temperature and moisture content of the returned material are kept stable, and the material flow into the granulator 120 is kept stable;
[0101] B: The first slurry concentration and flow in the pre-neutralization tank 110 are stable, and the neutralization degree is stable between 1.35-1.55;
[0102] C: The neutralization degree of the second slurry in the reactor is between 1.6-1.7, and the temperature of the second slurry does not exceed 150°C by adjusting the addition amount of tail washing liquid;
[0103] D: The first slurry and the second slurry entering the granulator 120 are uniformly sprayed on the material bed 121;
[0104] E: The particle size distribution of the returned material entering the granulator 120 is that the proportion of the particle size greater than 4.0 mm and less than 1.0 mm should not exceed 5.0%; the proportion of the particle size greater than 4.0 mm is less than 5%; the proportion of the particle size between 2.8-4.0 mm is between 30-40%; the proportion of the particle size between 2.0-2.8 mm is between 30%-40%; and the proportion of the particle size less than 2.0 mm is less than 20%.
[0105] The production process of the DAP production device 100 is described in detail as follows.
[0106] The first slurry generated by the reaction of the first phosphoric acid and ammonia gas in the pre-neutralization tank 110 enters the material bed 121 of the granulator 120 through the slurry pump 150, and the second slurry generated by the reaction of the second phosphoric acid and ammonia gas in the reactor enters the material bed 121 of the granulator 120.
[0107] The tail gas generated in the pre-neutralization tank 110 enters the tail gas treatment system 260, and the tail gas generated in the reactor enters the tail gas treatment system 260 through the granulator 120.
[0108] The ammonia gas in the ammonia adding device enters the granulator 120 through the ammonia adding pipe 140 to further adjust the state of the above-mentioned first slurry and second slurry to form DAP, so that the tail gas generated in the granulator 120 also enters the tail gas treatment system 260.
[0109] The above-mentioned DAP enters the dryer 160 for drying, and the tail gas generated by the dryer 160 also enters the tail gas treatment system 260.
[0110] The dried DAP is sieved by the flat sieve 220 to obtain finished products and non-finished products, the non-finished products including large-particle DAP and small-particle DAP, the large-particle DAP having a particle size larger than that of the finished products, and the small-particle DAP having a particle size smaller than that of the finished products, the large-particle DAP being transported to the crusher 270 for crushing and then returned to the return bin 210 through the return belt 240, the small-particle DAP being directly returned to the return bin 210 through the return belt 240, the finished products being cooled by the cooler 170 and then sieved by the finished product sieve 230 (to remove powder generated by mutual friction of the DAP in the above process and powder generated by collision of the DAP with the flat sieve 220, the cooler 170 and the finished product sieve 230) and then entering the coating machine 180; in addition, tail gas generated by the flat sieve 220, the crusher 270 and the cooler 170 in the above DAP production process is treated by the dust removal system 280 and then discharged by the fan.
[0111] The embodiment also provides a DAP production method, which is produced by using the DAP production device 100.
[0112] In the embodiment, the DAP production method using the DAP production device 100 is beneficial to produce high-quality DAP.
[0113] The DAP production method comprises the following steps:
[0114] The first phosphoric acid and ammonia gas are subjected to an ammonolysis reaction in the pre-neutralization tank to generate a first slurry;
[0115] The second phosphoric acid and ammonia gas are subjected to an ammonolysis reaction in the reactor to generate a second slurry;
[0116] The first slurry and the second slurry are subjected to an ammonolysis reaction with ammonia gas in the granulator 120 to form DAP.
[0117] In summary, the DAP production device 100 and the DAP production method are provided, the slurry in the DAP production device 100 is subjected to a reaction with ammonia gas in the ammonia feeder in the granulator 120 to further adjust the ammonolysis reaction and improve the yield of the DAP produced by the granulator 120.
[0118] In the description of the utility model, need understanding is, the term "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and so on indicate the orientation or positional relationship is the orientation that the device or element is in normal use, just is for the convenience of describing the utility model and simplifying the description, and is not indicate or imply the device or element that is indicated must have a particular orientation at any time, with a particular orientation structure and operation, therefore can not be understood as the restriction of the utility model in this aspect.
[0119] Although the specific embodiments of the utility model are described above, those skilled in the art should understand that this is only illustrative, the protection scope of the utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the utility model, but these changes and modifications all fall within the protection scope of the utility model.
Claims
1. A DAP production apparatus characterized by, The DAP production device comprises a pre-neutralization tank, a granulator, a reactor and an ammonia feeder; The outlet of the pre-neutralization tank is communicated with the granulator, and the pre-neutralization tank is used for carrying out an ammonium acid reaction between first phosphoric acid and ammonia gas to generate a first slurry; The outlet of the reactor is communicated with the granulator, and the reactor is used for carrying out an ammonium acid reaction between second phosphoric acid and ammonia gas to generate a second slurry; The ammonia feeder is communicated with the granulator, and the ammonia gas in the ammonia feeder, the first slurry and the second slurry all enter a material bed of the granulator to react to form DAP.
2. The DAP production apparatus according to claim 1, characterized in that, The ammonia feeder comprises a plurality of ammonia feeding pipes, and the plurality of ammonia feeding pipes enter the inside of the granulator from the head and / or tail of the granulator.
3. The DAP production apparatus of claim 2, wherein, The plurality of ammonia feeding pipes are uniformly spaced from the tail of the granulator to the head of the granulator.
4. The DAP production apparatus of claim 2, wherein, The ammonia feeding pipe comprises an inlet and an outlet, the inlet is located outside the granulator and is used for discharging ammonia gas, and the outlet is located inside the granulator and is inserted into the material bed.
5. The DAP production apparatus of claim 1, wherein, The DAP production device further comprises a slurry pump for pumping the first slurry into the material bed.
6. The DAP production apparatus of claim 1, wherein, The reactor comprises a reaction pipe, a first end of the reaction pipe is located outside the granulator and is used for introducing the second phosphoric acid and the ammonia gas to carry out an ammonium acid reaction, and a second end of the reaction pipe is located inside the granulator and is used for conveying the second slurry to the material bed.
7. The DAP production apparatus of claim 1, wherein, The first phosphoric acid comprises 42% content of phosphorus pentoxide, and the second phosphoric acid comprises 52% content of phosphorus pentoxide.
8. The DAP production apparatus of claim 1, wherein, The DAP production device further comprises a dryer, a cooler, a coating machine and a packaging machine; The inlet of the dryer is communicated with the granulator and is used for drying DAP from the granulator, the outlet of the dryer is communicated with the cooler, and the cooler, the coating machine and the packaging machine are sequentially connected.
9. The DAP production apparatus of claim 8, wherein, The DAP production device further comprises an elevator, a return bin and a screening system; the screening system comprises a flat screen and a finished product screen, The flat screen, the cooler, the finished product screen and the coating machine are sequentially connected; The elevator is connected with the dryer and is used for conveying the dried DAP to the flat screen, the flat screen is used for screening finished products and non-finished products of the DAP, the finished products enter the cooler, the finished product screen is used for further screening the cooled finished products to enter the coating machine, and the non-finished products enter the granulator through the return bin.