The compound fertilizer ammonium phosphate granulation production line is a type of equipment used for producing compound fertilizers. Here is a brief introduction to its working principles, main equipment, and process flow.

I. Working Principle

1. Neutralization Reaction: Neutralization reactions occur between liquid ammonia and acids like sulfuric acid and phosphoric acid. For example, ammonia water reacts with sulfuric acid to produce ammonium sulfate, releasing a large amount of heat.
2. Binding and Granulation: The high-temperature ammonium sulfate solution or other complex salt solutions produced by the reaction have high viscosity and act as a binder. This binder agglomerates powdered materials like potassium chloride, monoammonium phosphate (MAP), and urea into granules within the granulator.
3. Complex Salt Formation and Solidification: During the granulation process, complex chemical reactions also occur between the various raw materials, forming complex salts like potassium ammonium sulfate, potassium ammonium phosphate, and potassium ammonium chloride. These complex salts ultimately form solid solutions, which help solidify the granules and increase their strength.

II. Main Equipment

1. Ammonia Station Equipment: This includes the liquid ammonia tank, ammonia pressure booster, ammonia evaporator, gas ammonia tank, pipelines, valves, and flow meters. They are used to store, pressurize, and evaporate liquid ammonia, and to transport the resulting gas to the reaction system.
2. Acid Station Equipment: This includes a sulfuric acid storage tank, sulfuric acid pump, sulfuric acid flow meter, dissolution tank, slurry pump, acid mixing tank, acid mixing pump, intermediate tank, slurry pump, mixed acid flow meter, tail gas fan, tail gas absorption device, scrubbing liquid circulation pump, and pipeline valves. This equipment is mainly used to store and transport sulfuric acid, mix and react it with other raw materials, and treat the resulting tail gas.
3. Granulation Equipment: A rotary drum granulator is typically used. It consists of a tilted cylindrical rotating drum, a motor, and a speed reducer. Raw materials and recycled fines are fed from the upper end of the drum and mixed with the high-temperature slurry sprayed from the tubular neutralizer reactor. The material is then granulated as the drum rotates.
4. Drying Equipment: A rotary kiln dryer is generally used. It employs a counter-current drying method, using hot air to dry the wet fertilizer granules. This process converts the liquid cross-linking inside the granules into solid cross-linking, increasing their strength.
5. Screening Equipment: Equipment like vibratory screens and trommel screens are used to sift the dried granules. Granules that meet the standard size are classified as the final product. Smaller and larger granules are processed and returned to the front of the granulator as recycled fines.

III. Process Flow

1. Raw Material Preparation: Solid raw materials like potassium chloride, MAP, and urea undergo pretreatment steps such as crushing, screening, and weighing to meet the appropriate particle size and ratio requirements. At the same time, liquid raw materials like concentrated sulfuric acid are stored in the acid station for use.
2. Granulation: Solid raw materials from the batching process and recycled fines from the system enter the rotary drum granulator. Liquid ammonia, after being processed by the ammonia station, is split into two streams. One stream reacts rapidly with diluted sulfuric acid in a tubular reactor. The resulting high-temperature ammonium sulfate solution is evenly sprayed onto the material bed in the granulator via atomizing nozzles. The other stream of gaseous ammonia, mixed and vaporized with steam, enters the material bed through a mixing distributor, where it continues to react with MAP and other materials. The wet and dry materials agglomerate into granules as the granulator rotates.
3. Drying: The wet granules from the granulator are conveyed to a rotary dryer via an elevator or belt conveyor. They are dried with hot air at a specific temperature to remove moisture.
4. Screening: The dried granules are sent to a screening machine. Qualified granules proceed to subsequent coating and packaging processes as the final product. Oversized granules are crushed and returned along with fine granules to the granulation system to be re-granulated.
5. Tail Gas Treatment: Tail gas from drying, cooling, and dust collection is treated through a three-stage process involving a cyclone dust collector, gravity settling, and a water bath scrubber to ensure emissions meet standards and reduce environmental pollution.

IV. Features of the Compound Fertilizer Ammonium Phosphate Granulation Production Line

The compound fertilizer ammonium phosphate granulation production line is an advanced granulation process that combines ammoniation and acidulation reactions. It offers significant advantages in fertilizer production, with its core features primarily centered on the following aspects:

1. Energy-Efficient and Cost-Effective Process Ammonium phosphate granulation involves the direct reaction of ammonia (e.g., liquid ammonia, ammonia water) with acidic raw materials like phosphoric acid and sulfuric acid inside the granulator. The large amount of heat released from this reaction provides the thermal energy needed for granulation, reducing reliance on external heat sources like steam. The reaction products, such as ammonium phosphate and ammonium sulfate, act as a natural binding phase, reducing the amount of water needed and significantly lowering energy consumption in the subsequent drying stage (more than 30% savings compared to traditional drum granulation). The compact process flow and high raw material conversion rate also minimize material loss, further reducing overall production costs.
2. Excellent Product Quality and Stable Physical Properties The compound fertilizer granules produced by this line are spherical or nearly spherical, with a high degree of uniformity (over 90% of particles are between 2-4.75mm in size). The granules have high compressive strength (≥25N) and excellent resistance to breakage and caking, making them easy to store, transport, and apply with machinery. Because the liquid phase is evenly distributed during granulation, nutrients are thoroughly mixed within each granule, avoiding issues like “raw cores” or nutrient segregation common in traditional processes and ensuring product nutrient uniformity.
3. High Nutrient Concentration and Flexible Formulation Ammonium phosphate granulation allows for flexible adjustment of basic nutrient content (like nitrogen and phosphorus) by controlling the reaction ratio of ammonia to acid. This makes it easy to produce high-concentration compound fertilizers with a total nutrient content (N+P₂O₅+K₂O) of over 45%, and up to more than 60%. The production line is also highly adaptable to various raw materials, allowing for combinations with potassium chloride, potassium sulfate, organic fertilizers, etc. This enables the production of multi-component fertilizers containing nitrogen, phosphorus, potassium, micronutrients, and organic matter to meet the specific fertilization needs of different crops and soils.
4. Outstanding Environmental Performance and Reduced Pollution The high efficiency of the ammonia-acid reaction (ammonia utilization rate can reach over 95%) significantly reduces atmospheric pollution from ammonia escape. A配套 exhaust gas scrubbing system can recover and treat the small amount of unreacted ammonia and dust, ensuring tail gas emission indicators (such as ammonia concentration ≤10mg/m³) are well below national standards. Furthermore, the process generates very little wastewater, and it can be recycled to achieve “zero discharge,” meeting green chemical production requirements.
5. Continuous and Stable Production with a High Degree of Automation Modern ammonium phosphate granulation lines are generally equipped with a DCS (Distributed Control System) automation system, which can precisely and in real time control key parameters like raw material ratio, reaction temperature, granulation moisture, and granule size. This ensures a continuous and stable production process and reduces human error. A single production line can have a capacity ranging from 50,000 to 600,000 tons/year, meeting the production needs of companies of different scales. The equipment also has a low failure rate and low maintenance costs.
6. Balanced Nutrient Release and Enhanced Crop Absorption Efficiency The compound fertilizer produced by ammonium phosphate granulation contains nitrogen primarily in the form of ammonium nitrogen and phosphorus as a combination of water-soluble and citrate-soluble phosphorus. The nutrient release rate is moderate, satisfying the rapid demands of crops in their early stages while providing sustained fertilization in later stages, reducing nutrient loss. The porous granule structure also facilitates the activity of soil microorganisms, which can promote the absorption and utilization of nutrients by crops, increasing fertilizer utilization efficiency by 10-15%.

In summary, the compound fertilizer ammonium phosphate granulation production line, with its energy-efficient, high-quality, and environmentally stable characteristics, has become one of the mainstream processes for producing high-concentration compound fertilizers, especially suitable for the needs of large-scale, precision modern agricultural fertilizer production.

V. Application Fields of the Compound Fertilizer Ammonium Phosphate Granulation Production Line

Due to the uniform nutrients, high stability, and high utilization rate of the compound fertilizers it produces, the compound fertilizer ammonium phosphate granulation production line has a wide range of applications.

1. In agriculture, the compound fertilizer produced by this line is a vital guarantee for the growth of grain crops. For example, for wheat, this compound fertilizer plays an important role at all stages of its growth. During the seedling stage, it slowly releases nitrogen to meet the initial nutrient needs, promoting root development and seedling growth. During the tillering stage, a sufficient nutrient supply can increase the number of effective tillers. During the grain-filling stage, the rich phosphorus and potassium elements can increase the thousand-grain weight, thereby boosting yield. For corn, the compound fertilizer provides a balanced nutrition during the seedling stage, helping the seedlings grow robustly. During the grain-filling stage, sufficient phosphorus and potassium can increase corn kernel weight, improving corn quality and yield. In rice cultivation, ammonium phosphate granulated compound fertilizer can also meet its needs for nitrogen, phosphorus, and potassium at different growth stages, promoting rice tillering, heading, and grain filling, and increasing the seed setting rate.The application of the compound fertilizer ammonium phosphate granulation production line is also widespread in the cultivation of economic crops. Cotton requires a large amount of nutrients for growth. The compound fertilizer produced by this line can provide continuous nutritional support, promoting branch and leaf growth, flowering, and boll formation, and improving cotton yield and fiber quality. Rapeseed has a large demand for nitrogen, phosphorus, and potassium during its growth. Ammonium phosphate granulated fertilizer can meet this demand, helping rapeseed grow and develop, and increasing rapeseed yield and oil content. As a fertilizer-loving crop, sugarcane can be supplied with sufficient nutrients by this compound fertilizer, promoting the growth of its stalks and increasing sweetness and yield.

   Vegetable cultivation is inseparable from high-quality fertilizer, and the compound fertilizer produced by this line performs excellently in this field. In tomato cultivation, it can provide balanced nutrition, promoting flowering and fruiting, improving fruit quality and yield, and reducing problems like malformed fruit caused by imbalanced fertilizer. Cucumbers have a frequent need for nutrients during their growth, and this compound fertilizer can continuously supply them, promoting vine growth and fruit development, and increasing cucumber yield. Furthermore, this compound fertilizer works well in the cultivation of various vegetables like peppers, eggplants, and cabbage, improving vegetable quality and yield.

   In fruit tree cultivation, the compound fertilizer produced by this line also holds an important position. Fruit trees like apples and pears require different nutrients throughout their growth cycle. This compound fertilizer can provide the corresponding nutrition based on the fruit tree's needs, promoting flowering and fruiting, and improving fruit color, taste, and yield. Citrus trees are sensitive to nutrients. The uniform nutrients of ammonium phosphate granulated fertilizer can meet their needs, reducing phenomena like flower and fruit drop caused by nutrient imbalance.

2. In forestry, the cultivation of artificial forests also relies on the compound fertilizer produced by the ammonium phosphate granulation production line. During the seedling cultivation stage, the compound fertilizer can provide sufficient nutrients, improving seedling survival rates and growth speed. For mature trees, an appropriate amount of this compound fertilizer can promote tree growth and increase timber yield.
3. In horticulture, this compound fertilizer can be used for flower cultivation and lawn maintenance. In flower cultivation, it can promote the growth and flowering of flowers, prolonging the flowering period and improving their ornamental value. In lawn maintenance, the compound fertilizer provides balanced nutrition for the lawn grass, keeping the lawn green and lush.
4. In some special soil environments, such as saline-alkali or barren soils, the compound fertilizer ammonium phosphate granulation production line can produce specially formulated compound fertilizers based on the soil characteristics. These fertilizers can improve soil structure, increase soil fertility, create a good environment for crop growth, and promote crop growth in these special soil environments.

VI. Key Selection Criteria for a Compound Fertilizer Ammonium Phosphate Granulation Production Line

In the field of compound fertilizer production, the ammonium phosphate granulation process is widely used because it can produce high-concentration, high-quality products. Choosing a suitable ammonium phosphate granulation production line requires a comprehensive consideration of multiple factors to ensure stable, efficient production that meets environmental and quality requirements. Here are the key selection criteria:

1. Matching Production Needs First, you need to be clear about your production scale needs, including annual capacity and daily output. Production lines of different scales vary significantly in equipment configuration, footprint, and investment costs. A small-scale line may focus on flexibility and initial investment costs, suitable for small-batch, multi-product production. A large-scale line, on the other hand, requires emphasis on continuous stability and economies of scale to meet the needs of large-batch, single or a few product types. You should also consider future capacity expansion needs and choose a line design with room for growth.
2. Raw Material Adaptability The common raw materials for the ammonium phosphate granulation process include urea, MAP, potassium chloride, potassium sulfate, etc. These raw materials have different moisture content, particle sizes, and chemical reaction characteristics. The production line must be able to adapt to the characteristics of the selected raw materials to avoid problems like material sticking, equipment blockages, or incomplete reactions. For example, for high-moisture raw materials, appropriate pretreatment equipment like dryers and crushers should be included to ensure the raw materials meet process requirements before entering the granulation system. You should also consider the stability of your raw material sources; the production line's ability to handle different batches of raw materials is also important.
3. Ensuring Process Stability The core of ammonium phosphate granulation lies in the chemical reaction inside the reactor and the granule formation process inside the granulator. Process stability directly affects product quality. The production line should have the ability to precisely control key parameters like reaction temperature, pH value, and material ratio. If the reaction temperature is too high or too low, or the pH value is not properly controlled, it can lead to incomplete reactions, insufficient granule strength, and uneven nutrient distribution. Choosing a production line equipped with an online monitoring and automatic adjustment system can ensure real-time monitoring of process parameters and timely adjustments, reducing human error and guaranteeing the stability and consistency of the process.
4. Equipment Quality and Durability Equipment quality is the foundation of stable production. The quality of key equipment like the granulator, reactor, dryer, cooler, and screening machine is especially critical. Since the compound fertilizer production environment may contain corrosive substances (such as acidic gases from the ammonia-acid reaction), the equipment materials must have good corrosion resistance. This may involve using stainless steel or professional anti-corrosion treatments. The equipment's structural design should also be reasonable, facilitating operation, maintenance, and repair to reduce downtime. Checking the equipment manufacturer's manufacturing process, quality inspection standards, and feedback from past users can help you assess the durability of the equipment.
5. Energy Consumption and Environmental Compliance In the context of increasingly strict environmental policies, the line's energy consumption and environmental performance are important considerations. For energy consumption, focus on the energy efficiency of equipment like the dryer and hot air furnace. Choose energy-efficient equipment to reduce the cost of consuming energy like coal, electricity, and water. For environmental protection, the production line must be equipped with effective dust removal, waste gas treatment, and wastewater treatment systems. Dust will be generated during granulation, drying, and screening, so a high-efficiency bag filter or electrostatic precipitator should be installed. The ammonia-acid reaction may generate waste gases like ammonia, which must be treated with equipment like absorption towers to ensure emissions meet national standards. The small amount of wastewater generated during production must also be treated to meet discharge standards or be recycled.
6. Automation and Intelligence Level A higher level of automation and intelligence can improve production efficiency, reduce labor costs, and enhance the stability of product quality. Choose a production line equipped with a PLC control system and a human-machine interface. This allows for automated control of the entire production process, including automatic linkage of raw material metering, conveying, reaction parameter adjustment, and finished product packaging. Intelligent functions like remote monitoring, data collection and analysis, and fault warning can help managers monitor the production status in real time, quickly identify and solve problems, and optimize the production process.
7. After-Sales Service and Technical Support The equipment in an ammonium phosphate granulation production line is complex, and installation, commissioning, and maintenance require professional technical support. Choosing a manufacturer with excellent after-sales service and technical support is crucial. The manufacturer should provide guidance for equipment installation, commissioning services to ensure the line is smoothly put into operation, and comprehensive technical training to enable operators to master equipment operation and daily maintenance skills. During operation, they should be able to respond to maintenance needs in a timely manner and provide an adequate supply of spare parts to reduce downtime losses due to equipment failure. The manufacturer's technical R&D capabilities are also important, as they can provide support for future technical upgrades and process improvements.
8. Cost-Benefit Analysis You should perform a cost-benefit analysis by comprehensively considering the line's initial investment, operating costs, maintenance costs, and product revenue. The initial investment includes not only the cost of equipment but also factory construction, equipment installation, and auxiliary facilities. Operating costs involve energy, raw material, and labor consumption. When choosing, don't just go for the lowest price. Instead, evaluate factors like equipment quality, performance, energy consumption, and environmental features to choose the line with the best cost-performance ratio. You should also consider the impact of the line's production efficiency on product cost; a highly efficient and stable line can reduce the unit cost of your products and increase your market competitiveness.
9. Product Quality Assurance The production line must be able to stably produce compound fertilizer products that meet quality standards, including granule strength, particle size uniformity, moisture content, and nutrient content and uniformity. The performance of the granulator directly affects the quality of the granules, so you should choose a granulator with good granulation results and high granule uniformity. The screening system must be able to effectively separate off-spec granules to ensure the finished product particle size meets requirements. The line should also have the conditions or interfaces for product quality testing to facilitate timely testing of the finished product and ensure consistent quality.
10. Site and Environmental Adaptability Based on your factory site conditions, choose a production line with a suitable layout. Consider the line's footprint, the distance between equipment, and the material conveying paths to ensure a reasonable factory layout that facilitates operation and material flow. You should also consider the impact of the production environment on the line, such as ventilation, lighting, temperature, and humidity, and take necessary measures to ensure the line's normal operation and the safety of the operators.
11. Industry Cases and Reputation Reference Learn about the actual operation of different brands or models of ammonium phosphate granulation production lines used by other companies in the same industry. Refer to their usage experience and reputation. Choosing an equipment manufacturer and production line model with a good reputation and numerous successful cases in the industry can reduce your selection risk. You can obtain more information on production line performance and usage effects through industry exhibitions, technical exchange meetings, and company visits.

In summary, choosing a compound fertilizer ammonium phosphate granulation production line is a systematic process. You must comprehensively consider factors like production needs, raw material characteristics, process stability, equipment quality, energy consumption and environmental compliance, automation level, and cost-effectiveness. By also considering the manufacturer's after-sales service and industry reputation, you can choose the production line that best fits your company's specific situation and provides a strong guarantee for your production and operations.