CN114560453A - Preparation method of diammonium phosphate - Google Patents
Preparation method of diammonium phosphate Download PDFInfo
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- CN114560453A CN114560453A CN202210297054.3A CN202210297054A CN114560453A CN 114560453 A CN114560453 A CN 114560453A CN 202210297054 A CN202210297054 A CN 202210297054A CN 114560453 A CN114560453 A CN 114560453A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/28—Ammonium phosphates
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Abstract
The invention belongs to the technical field of agricultural fertilizers, and particularly relates to a preparation method of diammonium phosphate. The preneutralization reaction kettle neutralizes slurry for the first time, and evaporation purification is carried out for the first time in the process of neutralization for the first time; the tubular reactor neutralizes the slurry for the second time, and the second evaporation purification is carried out in the second neutralization process. Through twice evaporation and purification of the slurry, impurities are effectively removed, and the quality of the slurry is improved. In addition, materials with the size larger than 4mm screened out from the upper layer of the double-layer process screen are sent into a crusher to be crushed, and the crushed materials and fine powder screened out from the lower layer of the double-layer process screen are sent into a material returning conveying belt and sent to a granulator through a bucket elevator of the granulator. The large-particle materials separated out can be recycled for secondary utilization, and the fine powder materials can be recycled to the granulator, so that the production cost is reduced, and the environment is protected by recycling.
Description
Technical Field
The invention belongs to the technical field of agricultural fertilizers, and particularly relates to a preparation method of diammonium phosphate.
Background
Diammonium phosphate is a binary high-efficiency compound fertilizer containing two main nutrient elements of nitrogen and phosphorus, and is widely applied to agricultural production. Diammonium phosphate can be used as a base fertilizer and an additional fertilizer; is suitable for both dry-land crops and paddy-field crops; the fertilizer can be used for acid soil and alkaline soil. The diammonium phosphate has obvious yield-increasing effect on the growth of crops, and the amino acid used as a bioactive synergistic carrier is matched with a large amount of fertilizers such as urea, ammonium phosphate, compound fertilizers and the like to produce fertilizer value-added products, so that the nutritional function of the traditional fertilizers can be improved, the fertilizer utilization rate is high, and the diammonium phosphate is an important direction for the research and development of novel fertilizer products.
In the prior art, diammonium phosphate obtained by reaction contains more impurities, which affect the quality of finished products and are generated in the neutralization reaction process of ammonia and phosphoric acid. Different kinds of complex compounds generated by the reaction coexist with ammonium phosphate slurry obtained by the reaction of ammonia and phosphoric acid. The quality of the ammonium phosphate slurry is severely affected by the presence of these complex compounds. The current process flow for producing amino acid value-added fertilizer products is as follows: the production process of the traditional fertilizer comprises the steps of adding the amino acid raw powder into urea, ammonium phosphate, compound fertilizer and the like according to a certain proportion, wherein the process is complex in flow and high in cost, and the amino acid raw powder is not easy to mix uniformly and needs additional storage tanks, spraying equipment and the like.
In addition, the materials granulated by the granulator have different particle sizes. The large-particle materials screened out can not be recycled for secondary utilization, and particularly the fine powder materials can not be well recycled and are often discarded, so that not only is waste caused, but also the environment is polluted.
Disclosure of Invention
In order to overcome the defects in the prior art, the technical scheme of the invention provides a preparation method of diammonium phosphate containing amino acid, which has high quality of a produced finished product.
The preparation method of the diammonium phosphate comprises the following steps,
step 1: pouring liquid ammonia in an ammonia tank into a pre-neutralization reaction kettle, pouring 46-48% of concentrated phosphoric acid in a phosphoric acid tank into a device, adding an amino acid source into the phosphoric acid for acidolysis, conveying the phosphoric acid into the pre-neutralization reaction kettle, a washing system and a tubular reactor through a concentrated phosphoric acid conveying pump, pouring sulfuric acid in a sulfuric acid tank into a sulfuric acid storage tank, and conveying the sulfuric acid into the pre-neutralization reaction kettle, the washing system and the tubular reactor through a sulfuric acid pump;
step 2: pouring the concentrated phosphoric acid and a washing solution into the preneutralization reaction kettle and stirring, wherein the stirring speed during stirring is 52-62 r/min, the stirring time is 15-20 min, ammonia is conveyed into the preneutralization reaction kettle during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept at 0.9-1.1, the water content of the generated slurry is less than 18-25%, the reaction temperature is 100-125 ℃, the slurry is subjected to first evaporation purification, evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are sent to a washing procedure for washing, and overflowed ammonia and fluorine are absorbed;
and step 3: conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing liquid and stirring, wherein the stirring speed during stirring is 45-55 r/min, the stirring time is 15-20 min, ammonia is conveyed into the tubular reactor during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept at 1.4-1.7, the water content of the generated slurry is 4-10%, the reaction temperature is 110-140 ℃, the slurry is subjected to secondary evaporation purification, and the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are conveyed to a washing procedure for washing to absorb overflowed ammonia and fluorine;
and 4, step 4: feeding the generated slurry into a granulator through a slurry pump for spraying granulation, wherein an ammonia distributor is arranged in the granulator, ammonia is supplemented into a material bed layer of the granulator through the ammonia distributor, the particle size range of discharged materials of the granulator is 2-4 mm, the water content is 3-5%, the temperature is 75-95 ℃, the N/P is controlled to be 1.7-2.0, evaporated water in the granulator and overflowed ammonia and dust are sucked into a washing system, and ammonia and dust are washed and recovered;
and 5: feeding the material after the guniting granulation into a rotary dryer through a chute for drying treatment, wherein the inlet gas temperature of the rotary dryer is 150-350 ℃, the outlet gas temperature is 75-95 ℃, the outlet material temperature is 70-90 ℃, the outlet water content is not more than 2.5%, and the outlet of the rotary dryer is provided with an electromagnetic iron remover;
step 6: conveying the dried material to a double-layer process sieve through an outlet of the rotary dryer, sieving the material until the grain size of the qualified finished product is not more than 4mm, and cooling to obtain the finished product.
In a specific embodiment, in step 2, the feed rate of ammonia to the preneutralization reactor is:
kg/h NH3＝(N/P)×(kgh P2O5)×17/71+(kg/h SO4 2-)×34/98。
in a specific embodiment, in step 3, the feed rate of ammonia to the tubular reactor is:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98。
in a specific embodiment, in step 3, the wash liquor comprises 3/5 of the volume of the tubular reactor.
In a specific embodiment, the preneutralization reactor, the tubular reactor and the ammonia distributor are each provided with a steam purge.
In a specific embodiment, in the step 5, after the flue gas discharged from the hot blast stove is mixed with the fluidized bed cooling tail gas fed by the circulating fan, hot air is formed and enters the rotary dryer to dry the material.
In a specific embodiment, in step 6, the material with the size larger than 4mm sieved out from the upper layer of the double-layer process screen is sent to a crusher for crushing, and the crushed material and the fine powder sieved out from the lower layer of the double-layer process screen are sent to a return conveyer belt and sent to the granulator through a bucket elevator of the granulator.
In a specific embodiment, the front end of the crusher is provided with a distributor, and materials are fed into the crusher through the distributor to be crushed.
In a specific embodiment, in step 6, the cooled finished product is sent to a wrapping drum and wrapped with wrapping oil, and then sent to a bulk storage via a conveyor belt.
In a specific embodiment, the amino acid source is an amino acid source obtained by biological fermentation or an amino acid source obtained by phosphoric acid hydrolysis of biomass waste.
Pouring concentrated phosphoric acid and washing liquid into a pre-neutralization reaction kettle, and conveying ammonia into the reaction kettle to generate ammonium phosphate slurry. The slurry is evaporated and purified for the first time, and the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are sent to a washing procedure for washing, so that overflowed ammonia and fluorine are absorbed.
And (3) conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing solution, and conveying ammonia in the tubular reactor to generate ammonium phosphate slurry. And (3) evaporating and purifying the slurry for the second time, and sending the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry to a washing procedure for washing to absorb overflowed ammonia and fluorine.
The preneutralization reaction kettle neutralizes slurry for the first time, and evaporation purification is carried out for the first time in the process of neutralization for the first time; the tubular reactor neutralizes the slurry for the second time, and the second evaporation purification is carried out in the second neutralization process. Through twice evaporation and purification of the materials, impurities are effectively removed, and the quality of the slurry is improved.
In addition, materials with the size larger than 4mm screened out from the upper layer of the double-layer process screen are sent into a crusher to be crushed, and the crushed materials and fine powder screened out from the lower layer of the double-layer process screen are sent into a material returning conveying belt and sent to a granulator through a bucket elevator of the granulator. The large-particle materials separated out can be recycled for secondary utilization, and the fine powder materials can be recycled to the granulator, so that the production cost is reduced, and the environment is protected by recycling. Therefore, the production method is suitable for popularization and application in related fields.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.
Thus, the following detailed description of embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.
In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used for the convenience of description and to simplify description, but do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.
In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact of the first and second features, or may comprise contact of the first and second features not directly but through another feature in between. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The first embodiment is as follows:
the preparation method of the compound fertilizer comprises the following steps:
step 1: pouring liquid ammonia in an ammonia tank into a pre-neutralization reaction kettle, pouring 46% concentrated phosphoric acid in a phosphoric acid tank into a device, adding an amino acid source into the phosphoric acid for acidolysis, conveying the phosphoric acid into the pre-neutralization reaction kettle, a washing system and a tubular reactor through a concentrated phosphoric acid conveying pump, pouring sulfuric acid in a sulfuric acid tank into a sulfuric acid storage tank, and conveying the sulfuric acid into the pre-neutralization reaction kettle, the washing system and the tubular reactor through a sulfuric acid pump;
step 2: pouring concentrated phosphoric acid and a washing solution into a preneutralization reaction kettle and stirring, wherein the stirring speed during stirring is 57r/min, the stirring time is 16min, ammonia is conveyed into the preneutralization reaction kettle during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept between 0.9 and 1.1, the water content of the generated slurry is less than 18 to 22 percent, the reaction temperature is 100 to 125 ℃, the slurry is subjected to first evaporation purification, evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are conveyed to a washing procedure for washing, and overflowed ammonia and fluorine are absorbed.
Specifically, the feed rate for feeding ammonia into the preneutralization reactor is:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and step 3: and (3) conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing liquid, wherein the washing liquid accounts for 3/5 of the volume of the tubular reactor, and stirring. The stirring speed during stirring is 47r/min, the stirring time is 18min, ammonia is conveyed into the tubular reactor during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept between 1.5 and 1.7, the water content of the generated slurry is 4 to 6 percent, and the reaction temperature is 110 to 140 ℃. And (3) evaporating and purifying the slurry for the second time, and sending the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry to a washing procedure for washing to absorb overflowed ammonia and fluorine.
Specifically, the feed rates for ammonia to the tubular reactor were:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and 4, step 4: and sending the generated slurry into a granulator through a slurry pump for spraying granulation, wherein an ammonia distributor is arranged in the granulator, and the ammonia distributor supplements ammonia into a material bed layer of the granulator. The particle size range of discharged materials of the granulator is 3-4 mm, the water content is 3-4%, the temperature is 75-95 ℃, the N/P is controlled to be 1.7-1.9, evaporated water in the granulator and overflowed ammonia and dust are sucked into a washing system, and the ammonia and dust are washed and recovered.
And 5: and (3) feeding the material subjected to guniting granulation into a rotary dryer through a chute for drying treatment, wherein the inlet gas temperature of the rotary dryer is 150-350 ℃, the outlet gas temperature is 75-95 ℃, the outlet material temperature is 70-90 ℃, the outlet water content is not more than 2.5%, and an electromagnetic iron remover is arranged at the outlet of the rotary dryer. The electromagnetic iron remover is used for absorbing bulk metal particles on the materials, so that the purpose of further purifying the materials is achieved.
Specifically, after flue gas discharged by the hot blast stove is mixed with fluidized bed cooling tail gas fed by the circulating fan, hot air is formed and enters the rotary dryer to dry materials.
Step 6: and conveying the dried material to a double-layer process sieve through an outlet of the rotary dryer, and sieving the material to obtain a qualified finished product with the particle size of not more than 4 mm. And conveying the cooled finished product into a wrapping cylinder, wrapping the cooled finished product with wrapping oil, and conveying the finished product to a bulk storage through a conveying belt.
And if the material is larger than 4mm, feeding the material into a crusher for crushing, feeding the crushed material and the fine powder sieved out from the lower layer of the double-layer process sieve into a material returning conveying belt, conveying the material to a granulator through a bucket elevator of the granulator, and spraying slurry in the granulator for granulation again.
The large-particle materials separated out can be recycled for secondary utilization, and the fine powder materials can be recycled to the granulator, so that the production cost is reduced, and the environment is protected by recycling.
First, the finished product inspection project table
(watch one)
As can be seen from the table I, the total nutrient 67.1 of the finished product is greater than the technical requirement, and can provide more sufficient nutrients for crops; the moisture content is 0.72, which is less than the technical requirement, and the quality of the finished product is high; the granularity (2.0mm-4.0mm) reaches 95.7, which is far higher than the technical requirement, and the qualification rate of the finished product is high at the same time.
Example two:
the invention relates to a preparation method of diammonium phosphate, which comprises the following steps:
step 1: pouring liquid ammonia in an ammonia tank into a pre-neutralization reaction kettle, pouring 48 percent concentrated phosphoric acid in a phosphoric acid tank into a device, adding an amino acid source into the phosphoric acid for acidolysis, conveying the phosphoric acid into the pre-neutralization reaction kettle, a washing system and a tubular reactor through a concentrated phosphoric acid conveying pump, pouring sulfuric acid in a sulfuric acid tank into a sulfuric acid storage tank, and conveying the sulfuric acid into the pre-neutralization reaction kettle, the washing system and the tubular reactor through a sulfuric acid pump;
step 2: pouring concentrated phosphoric acid and a washing solution into a preneutralization reaction kettle and stirring, wherein the stirring speed during stirring is 52r/min, the stirring time is 19min, ammonia is conveyed into the preneutralization reaction kettle during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept between 0.9 and 1.1, the water content of the generated slurry is less than 18 to 22 percent, the reaction temperature is 100 to 125 ℃, the slurry is subjected to first evaporation purification, evaporated water in the slurry, a small amount of ammonia, fluorine and sucked air are conveyed to a washing procedure for washing, and overflowed ammonia and fluorine are absorbed.
Specifically, the feed rate for feeding ammonia into the preneutralization reactor is:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and step 3: and (3) conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing liquid, wherein the washing liquid accounts for 3/5 of the volume of the tubular reactor, and stirring. The stirring speed during stirring is 54r/min, the stirring time is 16min, ammonia is conveyed into the tubular reactor during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept between 1.6 and 1.7, the water content of the generated slurry is 4 to 5 percent, and the reaction temperature is 110 to 140 ℃. And (3) evaporating and purifying the slurry for the second time, and sending the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry to a washing procedure for washing to absorb overflowed ammonia and fluorine.
Specifically, the feed rates for ammonia to the tubular reactor were:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and 4, step 4: and sending the generated slurry into a granulator through a slurry pump for spraying granulation, wherein an ammonia distributor is arranged in the granulator, and the ammonia distributor supplements ammonia into a material bed layer of the granulator. The particle size range of discharged materials of the granulator is 3-4 mm, the water content is 3-4%, the temperature is 80-95 ℃, the N/P is controlled to be 1.8-1.9, evaporated water in the granulator and overflowed ammonia and dust are sucked into a washing system, and ammonia and dust are washed and recovered.
And 5: and (3) feeding the material subjected to guniting granulation into a rotary dryer through a chute for drying treatment, wherein the inlet gas temperature of the rotary dryer is 150-350 ℃, the outlet gas temperature is 75-95 ℃, the outlet material temperature is 70-90 ℃, the outlet water content is not more than 2.5%, and an electromagnetic iron remover is arranged at the outlet of the rotary dryer. The electromagnetic iron remover is used for absorbing bulk metal particles on the materials, so that the purpose of further purifying the materials is achieved.
Specifically, after flue gas discharged by the hot blast stove is mixed with fluidized bed cooling tail gas fed by the circulating fan, hot air is formed and enters the rotary dryer to dry materials.
Step 6: and conveying the dried material to a double-layer process sieve through an outlet of the rotary dryer, and sieving the material to obtain a qualified finished product with the particle size of not more than 4 mm. And conveying the cooled finished product into a wrapping cylinder, wrapping the cooled finished product with wrapping oil, and conveying the finished product to a bulk storage through a conveying belt.
And if the material is larger than 4mm, feeding the material into a crusher for crushing, feeding the crushed material and the fine powder sieved out from the lower layer of the double-layer process sieve into a material returning conveyer belt, conveying the material to a granulator through a bucket elevator of the granulator, and spraying slurry in the granulator again for granulation.
The large-particle materials separated out can be recycled for secondary utilization, and the fine powder materials can be recycled to the granulator, so that the production cost is reduced, and the environment is protected by recycling.
Second table finished product inspection item table
(watch two)
As can be seen from the table II, the total nutrient 66.7 of the finished product is greater than the technical requirement, and can provide more sufficient nutrients for crops; the moisture content is 0.74, which is less than the technical requirement, and the quality of the finished product is high; the granularity (2.0mm-4.0mm) reaches 95.1, which is far higher than the technical requirement, and the qualification rate of the finished product is high at the same time.
Example three:
the invention relates to a preparation method of diammonium phosphate, which comprises the following steps:
step 1: pouring liquid ammonia in an ammonia tank into a pre-neutralization reaction kettle, pouring 47% concentrated phosphoric acid in a phosphoric acid tank into a device, adding an amino acid source into the phosphoric acid for acidolysis, conveying the phosphoric acid into the pre-neutralization reaction kettle, a washing system and a tubular reactor through a concentrated phosphoric acid conveying pump, pouring sulfuric acid in a sulfuric acid tank into a sulfuric acid storage tank, and conveying the sulfuric acid into the pre-neutralization reaction kettle, the washing system and the tubular reactor through a sulfuric acid pump;
step 2: pouring concentrated phosphoric acid and a washing solution into a preneutralization reaction kettle and stirring, wherein the stirring speed during stirring is 58r/min, the stirring time is 14min, ammonia is conveyed into the preneutralization reaction kettle during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept between 0.9 and 1.1, the water content of the generated slurry is less than 19 to 21 percent, the reaction temperature is 100 to 125 ℃, the slurry is subjected to first evaporation purification, evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are conveyed to a washing procedure for washing, and overflowed ammonia and fluorine are absorbed.
Specifically, the feed rate for feeding ammonia into the preneutralization reactor is:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and step 3: and (3) conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing liquid, wherein the washing liquid accounts for 3/5 of the volume of the tubular reactor, and stirring. Stirring speed is 51r/min during stirring, stirring time is 17min, ammonia is conveyed into the tubular reactor during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept at 1.4-1.7, the water content of the generated slurry is 4-5%, and the reaction temperature is 110-140 ℃. And (3) evaporating and purifying the slurry for the second time, and sending the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry to a washing procedure for washing to absorb overflowed ammonia and fluorine.
Specifically, the feed rates for ammonia to the tubular reactor were:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98
and 4, step 4: and sending the generated slurry into a granulator through a slurry pump for spraying granulation, wherein an ammonia distributor is arranged in the granulator, and the ammonia distributor supplements ammonia into a material bed layer of the granulator. The particle size range of discharged materials of the granulator is 3-4 mm, the water content is 3-4%, the temperature is 75-95 ℃, the N/P is controlled to be 1.7-1.8, evaporated water in the granulator and overflowed ammonia and dust are sucked into a washing system, and the ammonia and dust are washed and recovered.
And 5: and (3) feeding the material subjected to guniting granulation into a rotary dryer through a chute for drying treatment, wherein the inlet gas temperature of the rotary dryer is 150-350 ℃, the outlet gas temperature is 75-95 ℃, the outlet material temperature is 70-90 ℃, the outlet water content is not more than 2.5%, and an electromagnetic iron remover is arranged at the outlet of the rotary dryer. The electromagnetic iron remover is used for absorbing bulk metal particles on the materials, so that the purpose of further purifying the materials is achieved.
Specifically, after flue gas discharged by the hot blast stove is mixed with fluidized bed cooling tail gas fed by the circulating fan, hot air is formed and enters the rotary dryer to dry materials.
Step 6: and conveying the dried material to a double-layer process sieve through an outlet of the rotary dryer, and sieving the material, wherein the grain size of a qualified finished product is not more than 4 mm. And conveying the cooled finished product into a wrapping cylinder, wrapping the cooled finished product with wrapping oil, and conveying the finished product to a bulk storage through a conveying belt.
And if the material is larger than 4mm, feeding the material into a crusher for crushing, feeding the crushed material and the fine powder sieved out from the lower layer of the double-layer process sieve into a material returning conveying belt, conveying the material to a granulator through a bucket elevator of the granulator, and spraying slurry in the granulator for granulation again.
The large-particle materials separated out can be recycled for secondary utilization, and the fine powder materials can be recycled to the granulator, so that the production cost is reduced, and the environment is protected by recycling.
Table three is the finished product inspection item table
(watch III)
As can be seen from the third table, the total nutrient of the finished product is 65.9, which is greater than the technical requirement, and can provide more sufficient nutrients for crops; the moisture content is 0.74, which is less than the technical requirement, and the quality of the finished product is high; the granularity (2.0mm-4.0mm) reaches 96.4, which is far higher than the technical requirement, and the qualification rate of the finished product is high at the same time.
Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the embodiments. Thus, the present embodiments are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention shall be included in the scope of the present invention.
Claims (10)
1. A preparation method of diammonium phosphate is characterized by comprising the following steps,
step 1: pouring liquid ammonia in an ammonia tank into a pre-neutralization reaction kettle, pouring 46-48% of concentrated phosphoric acid in a phosphoric acid tank into a device, adding an amino acid source into the phosphoric acid for acidolysis, conveying the phosphoric acid into the pre-neutralization reaction kettle, a washing system and a tubular reactor through a concentrated phosphoric acid conveying pump, pouring sulfuric acid in a sulfuric acid tank into a sulfuric acid storage tank, and conveying the sulfuric acid into the pre-neutralization reaction kettle, the washing system and the tubular reactor through a sulfuric acid pump;
step 2: pouring the concentrated phosphoric acid and a washing solution into the preneutralization reaction kettle and stirring, wherein the stirring speed during stirring is 52-62 r/min, the stirring time is 15-20 min, ammonia is conveyed into the preneutralization reaction kettle during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept at 0.9-1.1, the water content of the generated slurry is less than 18-25%, the reaction temperature is 100-125 ℃, the slurry is subjected to first evaporation purification, evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are sent to a washing procedure for washing, and overflowed ammonia and fluorine are absorbed;
and step 3: conveying the slurry in the pre-neutralization reaction kettle to a tubular reactor containing a washing liquid and stirring, wherein the stirring speed during stirring is 45-55 r/min, the stirring time is 15-20 min, ammonia is conveyed into the tubular reactor during stirring to generate ammonium phosphate slurry, the neutralization degree of the slurry is kept at 1.4-1.7, the water content of the generated slurry is 4-10%, the reaction temperature is 110-140 ℃, the slurry is subjected to secondary evaporation purification, and the evaporated water, a small amount of ammonia, fluorine and sucked air in the slurry are conveyed to a washing procedure for washing to absorb overflowed ammonia and fluorine;
and 4, step 4: feeding the generated slurry into a granulator through a slurry pump for spraying granulation, wherein an ammonia distributor is arranged in the granulator, ammonia is supplemented into a material bed layer of the granulator through the ammonia distributor, the particle size range of discharged materials of the granulator is 2-4 mm, the water content is 3-5%, the temperature is 75-95 ℃, the N/P is controlled to be 1.7-2.0, evaporated water in the granulator and overflowed ammonia and dust are sucked into a washing system, and ammonia and dust are washed and recovered;
and 5: feeding the material after the guniting granulation into a rotary dryer through a chute for drying treatment, wherein the inlet gas temperature of the rotary dryer is 150-350 ℃, the outlet gas temperature is 75-95 ℃, the outlet material temperature is 70-90 ℃, the outlet water content is not more than 2.5%, and the outlet of the rotary dryer is provided with an electromagnetic iron remover;
step 6: conveying the dried material to a double-layer process sieve through an outlet of the rotary dryer, sieving the material until the grain size of the qualified finished product is not more than 4mm, and cooling to obtain the finished product.
2. A process for the preparation of diammonium phosphate according to claim 1, wherein in step 2, the feeding rate of ammonia into the preneutralization reactor is:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98。
3. a process for preparing diammonium phosphate according to claim 1, characterized in that in step 3, the feed rates of ammonia to the tubular reactor are:
kg/h NH3＝(N/P)×(kg/h P2O5)×17/71+(kg/h SO4 2-)×34/98。
4. a process for the preparation of diammonium phosphate according to claim 1, characterized in that in step 3, said washing liquid occupies 3/5 of the volume of said tubular reactor.
5. The method for preparing diammonium phosphate according to claim 1, characterized in that the preneutralization reactor, the tubular reactor and the ammonia distributor are respectively provided with a steam blower.
6. The preparation method of diammonium phosphate according to claim 1, wherein in step 5, flue gas discharged from the hot blast stove is mixed with fluidized bed cooling tail gas fed by the circulating fan to form hot air, and the hot air enters the rotary dryer to dry the material.
7. The method for preparing diammonium phosphate according to claim 1, wherein in step 6, the material with a size larger than 4mm sieved out of the upper layer of the double-layer process screen is sent to a crusher for crushing, and the crushed material and the fine powder sieved out of the lower layer of the double-layer process screen are sent to a return conveyer belt and sent to the granulator through a bucket elevator of the granulator.
8. A process for preparing diammonium phosphate according to claim 7, wherein a distributor is provided at the front end of the crusher, and materials are fed into the crusher through the distributor for crushing.
9. The method for preparing diammonium phosphate according to claim 1, wherein in step 6, the cooled finished product is fed into a wrapping drum and wrapped with wrapping oil, and then is fed to a bulk storage through a conveyor belt.
10. The method for preparing diammonium phosphate according to claim 1, wherein the amino acid source is obtained by biological fermentation or by acidolysis of biomass waste with phosphoric acid.
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Citations (3)
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|---|---|---|---|---|
| CN101723340A (en) * | 2009-12-29 | 2010-06-09 | 中国海洋石油总公司 | Preparation method of diammonium phosphate |
| CN106241765A (en) * | 2016-08-24 | 2016-12-21 | 湖北祥云(集团)化工股份有限公司 | The production method of a kind of Diammonium phosphate (DAP) and system |
| CN110903108A (en) * | 2019-12-25 | 2020-03-24 | 贵州开磷集团矿肥有限责任公司 | Production method for increasing 64% diammonium phosphate nitrogen content and ammoniation granulator |
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Patent Citations (3)
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| CN101723340A (en) * | 2009-12-29 | 2010-06-09 | 中国海洋石油总公司 | Preparation method of diammonium phosphate |
| CN106241765A (en) * | 2016-08-24 | 2016-12-21 | 湖北祥云(集团)化工股份有限公司 | The production method of a kind of Diammonium phosphate (DAP) and system |
| CN110903108A (en) * | 2019-12-25 | 2020-03-24 | 贵州开磷集团矿肥有限责任公司 | Production method for increasing 64% diammonium phosphate nitrogen content and ammoniation granulator |
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