Preparation method of calcium ammonium nitrate
By using rotary differential granulator and tower granulation process in the preparation process of ammonium nitrate, problems such as low granulation yield and high energy consumption in the existing technology are solved, and efficient and environmentally friendly ammonium nitrate granules are achieved. , improving yield and corporate competitiveness.
Patent Information
- Application Number
- CN202510035578.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-09
- Publication Date
- 2025-02-25
AI Technical Summary
The existing disc granulator or circulating fluidized bed granulation is prepared into granulated ammonium nitrate products with low granulation yield, many circulating materials, high energy consumption, and poor granulation environment.
Limestone is decomposed by nitric acid, filtered through a filter press, and neutralized with three-effect evaporation and ammonia to make ammonium calcium nitrate liquid. Then, it is transported to the tower with a slurry pump, enters the first-stage cooling preparation tank, overflow enters the second-stage cooling preparation tank, overflow enters the filter, and then enters the rotary differential granulator for granulation. The granulated particles are cooled by heat exchange and exchange of dry air under the tower, solidifying into particles, forming strength through the drop height and time.
The granulation yield rate has been increased to more than 95%, energy consumption has been reduced, the granulation environment has been improved, the generation of waste and by-products has been reduced, and it has complied with stricter environmental protection standards, reduced production costs, and enhanced the market competitiveness of the enterprise.
Smart Images
Figure CN119503853A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of calcium ammonium nitrate preparation methods, in particular to a method for preparing calcium ammonium nitrate. Background Art
[0002] At present, the preparation methods of calcium ammonium nitrate are basically to use nitric acid to decompose limestone, filter it with a filter press, evaporate the filtered clear liquid through three-effect evaporation, add ammonia to adjust the pH value, and prepare calcium ammonium nitrate liquid, and then use a disc granulator or a circulating fluidized bed granulator to prepare granular calcium ammonium nitrate products. Both preparation methods have the characteristics of low granulation yield, large amount of recycled materials, high energy consumption, and poor granulation environment.
[0003] However, the existing technology has the following shortcomings: The existing disc granulator or circulating fluidized bed granulator is used to prepare granular calcium ammonium nitrate products. Both preparation methods have the characteristics of low granulation yield, large amount of recycled materials, high energy consumption and poor granulation environment. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing calcium ammonium nitrate in order to solve the problems of preparing granular calcium ammonium nitrate products by existing disc granulator or circulating fluidized bed granulation, both of which have the characteristics of low granulation yield, large amount of recycled materials, high energy consumption, poor granulation environment, etc.
[0005] To achieve the above object, the present invention provides the following technical solutions: The present invention is a method for preparing calcium ammonium nitrate, comprising: First, nitric acid is used to decompose limestone, and the filtered liquid is filtered by a filter press. The filtered clear liquid is evaporated by three effects and neutralized by adding ammonia to produce ammonium calcium nitrate liquid. Next, the slurry is pumped to the tower, enters the primary cooling preparation tank, overflows into the secondary cooling preparation tank, overflows into the filter, and then enters the rotary differential granulator for granulation, and the granulator sprays out liquid particles; Next, the dry air coming in from the bottom of the tower is cooled by heat exchange and solidified into particles, and its strength is formed through its falling height and falling time.
[0006] The specific steps of triple-effect evaporation are: first, the calcium ammonium nitrate solution is input into a triple-effect falling film evaporator, and the solvent is evaporated by heating, thereby concentrating the solution to a concentration of about 49%; Then, the concentrated solution is transported from the third-effect to the second-effect falling film evaporator by a circulation pump to continue the evaporation process. In the second-effect evaporator, the solution is further concentrated to a concentration of about 55%; The concentrated calcium ammonium nitrate solution after evaporation will then enter the crystallizer for crystallization to obtain the calcium ammonium nitrate product; According to the characteristics of calcium ammonium nitrate, a double-effect falling film vacuum concentration evaporator will be selected in the evaporation process, which includes components such as I-effect and II-effect heating evaporators and vapor-liquid separators.
[0007] As a further solution of the present invention: the pH value is adjusted by adding ammonia to prepare calcium ammonium nitrate (5-1-10) liquid.
[0008] As a further solution of the present invention: it also includes: The particles are then sent to the vibrating fluidized bed for cooling via the belt conveyor at the bottom of the tower. After cooling, they are screened to ensure that the particle size and shape meet the requirements and to remove unqualified particles. The unqualified products are collected by the shaftless spiral at the bottom of the tower, and are lifted to the top of the tower by the bucket elevator and enter the primary cooling and mixing tank. The screened finished products enter the powder flow for cooling, and then enter the packaging silo through the elevator. The packaged finished products are automatically heat-sealed, folded, sewn, and stacked for storage, and then enter the qualified product sales market.
[0009] As a further solution of the present invention: the exhaust pipe is connected to the induced draft fan and is connected to the venturi scrubber, and the blower blows the hot air in the tower.
[0010] It consists of a venturi tube (including a contraction tube, a throat and a diffuser) and a demister or cyclone separator. According to the different liquid supply methods, it can be divided into an external spray venturi tube and an internal spray venturi tube. When the gas passes through the contraction part of the venturi tube, its speed increases and the pressure decreases. In the throat part, the liquid is sprayed into the airflow, contacts with the high-speed airflow and atomizes to form tiny droplets. These droplets collide with dust particles or other pollutants in the airflow and are captured by inertia, interception and diffusion. After that, the airflow passes through the diffuser part and the speed decreases, and the droplets and captured pollutants are removed.
[0011] As a further solution of the present invention: the screening is divided into a first cylindrical screen (5) and a second cylindrical screen (6), the first cylindrical screen (5) has a fine aperture, and the second cylindrical screen (6) has a coarse aperture, and there are two packaging production lines (9) behind the packaging silo, and the packaging production lines (9) are connected to a warehouse (10).
[0012] As a further solution of the present invention: the temperature of the cooling preparation tank is controlled in the range of 130°C-90°C.
[0013] As a further solution of the present invention: the aperture of the granulator spray flange is Φ1.6-2.4.
[0014] As a further solution of the present invention: the method for preparing dry air by heating and dehumidification and the temperature index of the dry air under the tower are 20°C-50°C.
[0015] Compared with the prior art, the present invention has the following beneficial effects: The calcium ammonium nitrate solution obtained by the evaporation and concentration process is transported to the tower by a slurry pump, enters the first cooling preparation tank, overflows into the second cooling preparation tank, overflows into the filter, and then enters the rotary differential granulator for granulation. The liquid particles sprayed by the granulator are cooled by heat exchange with the dry air coming from the bottom of the tower, solidified into particles, and formed into strength through its falling height and falling time. The material collection belt at the bottom of the tower enters the vibrating fluidized bed for cooling, and then enters the screening after cooling. The unqualified products of different sizes enter the shaftless spiral collection at the bottom of the tower, and are lifted to the top of the tower by the bucket elevator and enter the first cooling mixing tank. The screened finished products enter the powder flow cooling, and enter the packaging silo after cooling. The finished packaged products are automatically heat-sealed, folded, sewn, and stacked for storage before entering the qualified product sales market. The granulation method at the back end of this preparation method adopts melt air-cooled granulation, and the granulation yield rate is increased to more than 95%, which improves the environment and reduces energy consumption. It is the most advanced preparation method, reduces the generation of waste and by-products, thereby reducing the impact on the environment, and helps to meet more stringent environmental standards. Improving the yield rate directly improves the utilization rate of raw materials, reduces the waste of raw materials, thereby reducing production costs, and helps to enhance the market competitiveness of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a flow chart for preparing calcium ammonium nitrate liquid of the present invention; Figure 2 This is a flow chart of calcium ammonium nitrate granulation of the present invention; Figure 3 This is a vertical view of the tower-type granulation of calcium ammonium nitrate of the present invention; Figure 4 It is the plan layout diagram of the calcium ammonium nitrate tower granulation of the present invention.
[0017] 1. Exhaust chimney; 2. induced draft fan; 3. vibrating fluidized bed; 4. blower; 5. first cylindrical screen; 6. second cylindrical screen; 7. belt conveyor; 8. elevator; 9. packaging production line; 10. warehouse. DETAILED DESCRIPTION
[0018] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.
[0019] See also Figures 1 to 4 In an embodiment of the present invention, a method for preparing calcium ammonium nitrate comprises: First, nitric acid is used to decompose limestone, and the filtered liquid is filtered by a filter press. The filtered clear liquid is evaporated by three effects and neutralized by adding ammonia to produce ammonium calcium nitrate liquid. Next, the slurry is pumped to the tower, enters the primary cooling preparation tank, overflows into the secondary cooling preparation tank, overflows into the filter, and then enters the rotary differential granulator for granulation, and the granulator sprays out liquid particles; Next, the dry air coming in from the bottom of the tower is cooled by heat exchange and solidified into particles, and its strength is formed through its falling height and falling time.
[0020] The specific steps of triple-effect evaporation are: First, the calcium ammonium nitrate solution is input into a triple-effect falling film evaporator, and the solvent is evaporated by heating, thereby concentrating the solution to a concentration of about 49%; Then, the concentrated solution is transported from the third-effect to the second-effect falling film evaporator by a circulation pump to continue the evaporation process. In the second-effect evaporator, the solution is further concentrated to a concentration of about 55%; The concentrated calcium ammonium nitrate solution after evaporation will then enter the crystallizer for crystallization to obtain the calcium ammonium nitrate product; According to the characteristics of calcium ammonium nitrate, a double-effect falling film vacuum concentration evaporator will be selected in the evaporation process, which includes components such as I-effect and II-effect heating evaporators and vapor-liquid separators; The pH value is adjusted by adding ammonia to prepare a calcium ammonium nitrate (5-1-10) liquid; The particles are then sent to the vibrating fluidized bed 3 for cooling via the belt conveyor 7 at the bottom of the tower. After cooling, they are screened to ensure that the particle size and shape meet the requirements and to remove unqualified particles. The unqualified products are collected by the shaftless spiral at the bottom of the tower, and are lifted to the top of the tower by the bucket elevator and enter the primary cooling and mixing tank. The sieved finished products enter the powder flow for cooling, and then enter the packaging silo through the elevator 8. The packaged finished products are automatically heat-sealed, folded, sewn, and stacked for storage, and enter the qualified product sales market; The exhaust pipe 1 is connected to the induced draft fan 2 and to the venturi scrubber, and the blower 4 blows the hot air into the tower; The screening is divided into a first cylindrical screen 5 and a second cylindrical screen 6. The aperture of the first cylindrical screen 5 is fine, and the aperture of the second cylindrical screen 6 is coarse. There are two packaging production lines 9 behind the packaging silo, and the packaging production lines 9 are connected to a warehouse 10; Cooling preparation tank, temperature control range 130℃-90℃; Granulator spray nozzle aperture: Φ1.6-2.4; The method of preparing dry air by heating and dehumidification and the temperature index of dry air under the tower are 20℃-50℃.
[0021] In this embodiment: by triple-effect evaporation, the calcium ammonium nitrate solution is input into a triple-effect falling film evaporator, and the solvent is evaporated by heating, thereby concentrating the solution to a concentration of about 49%; Then, the concentrated solution is transported from the third-effect to the second-effect falling film evaporator by a circulation pump to continue the evaporation process. In the second-effect evaporator, the solution is further concentrated to a concentration of about 55%; The calcium ammonium nitrate solution after evaporation and concentration will then enter the crystallizer for crystallization to obtain the calcium ammonium nitrate product. The calcium ammonium nitrate solution is transported to the tower by a slurry pump, enters the primary cooling preparation tank, overflows into the secondary cooling preparation tank, overflows into the filter, and then enters the rotary differential granulator for granulation. The liquid particles sprayed out by the granulator are cooled by heat exchange with the dry air coming in from the bottom of the tower, solidified into particles, and formed into strength through its falling height and falling time. The material collection belt at the bottom of the tower enters the vibrating fluidized bed for cooling, and then enters the screening after cooling. The unqualified products of different sizes enter the shaftless spiral collection at the bottom of the tower, and are lifted to the top of the tower by the bucket elevator and enter the primary cooling mixing tank. The screened finished products enter the powder flow cooling, and enter the packaging silo after cooling. The finished packaged products are automatically heat-sealed, folded, sewn, and stacked for storage, and enter the qualified product sales market. The granulation method at the back end of this preparation method adopts melt air-cooled granulation, and the granulation yield rate is increased to more than 95%, which improves the environment and reduces energy consumption. It is the most advanced preparation method, reduces the generation of waste and by-products, thereby reducing the impact on the environment, and helps to meet more stringent environmental protection standards. Improving the yield rate directly improves the utilization rate of raw materials, reduces the waste of raw materials, thereby reducing production costs, and helps to enhance the market competitiveness of enterprises. What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing calcium ammonium nitrate, characterized in that: include: First, nitric acid is used to decompose limestone, and the filtered liquid is filtered by a filter press. The filtered clear liquid is evaporated by three effects and neutralized by adding ammonia to produce ammonium calcium nitrate liquid. Next, the slurry is pumped to the tower, enters the primary cooling preparation tank, overflows into the secondary cooling preparation tank, overflows into the filter, and then enters the rotary differential granulator for granulation, and the granulator sprays out liquid particles; Next, the dry air coming in from the bottom of the tower is cooled by heat exchange and solidified into particles, and its strength is formed through its falling height and falling time.
2. A method for preparing calcium ammonium nitrate according to claim 1, characterized in that, The pH value is adjusted by adding ammonia to prepare calcium ammonium nitrate (5-1-10) liquid.
3. A method for preparing calcium ammonium nitrate according to claim 1, characterized in that: Also includes: The particles are then conveyed to the vibrating fluidized bed (3) via a belt conveyor (7) at the bottom of the tower for cooling. After cooling, the particles are screened to ensure that the particle size and shape meet the requirements and to remove unqualified particles. The unqualified products are collected by the shaftless spiral at the bottom of the tower, and are lifted to the top of the tower by the bucket elevator and enter the primary cooling and mixing tank. The sieved finished products enter the powder flow for cooling, and after cooling, they enter the packaging silo through the elevator (8). The packaged finished products are automatically heat-sealed, automatically folded, automatically sewn, and automatically stacked for storage, and enter the qualified product sales market.
4. A method for preparing calcium ammonium nitrate according to claim 3, characterized in that, The exhaust pipe (1) is connected to the induced draft fan (2) and is also connected to the venturi scrubber. The blower (4) blows dry hot air into the tower.
5. A method for preparing calcium ammonium nitrate according to claim 1, characterized in that, The screening is divided into a first cylindrical screen (5) and a second cylindrical screen (6); the first cylindrical screen (5) has a fine aperture, and the second cylindrical screen (6) has a coarse aperture; two packaging production lines (9) are arranged behind the packaging silo, and the packaging production lines (9) are connected to a warehouse (10).
6. The method for preparing calcium ammonium nitrate according to claim 1, characterized in that: The cooling and temperature reduction preparation tank has a temperature control range of 130°C-90°C.
7. The method for preparing calcium ammonium nitrate according to claim 1, characterized in that: The granulator spray nozzle aperture is Φ1.6-2.
4.
8. The method for preparing calcium ammonium nitrate according to claim 1, characterized in that: The method for preparing dry air by heating and dehumidification and the temperature index of the dry air under the tower are 20°C-50°C.