Large-particle Urea

1.Material Overview

Urea, also known as carbamide, is a final product of protein metabolism in humans and mammals, and a major organic nitrogen compound excreted by animals. It is a white granular, needle-like, or prismatic crystal; when mixed with heavy metals such as iron, it appears pale red or yellow.

Urea is a neutral fertilizer, containing no harmful components. Its hydrolysis products, NH4+ and HCO3-, can be absorbed and utilized by crops. Continuous application generally has no adverse effects on soil properties. It is suitable for various crops and soils.

2.Process Introduction

Molten urea from upstream is fed into the urea nozzle of the granulation drum, and the urea is sprayed onto the material curtain to make the seed crystals grow.

Air is sent into the fluidized bed dryer inside the granulation drum by a fluidizing air blower. During start-up, the fluidizing air is heated to the design temperature by a fluidizing air heater before entering the granulation drum.

The large granular urea intermediate product coming out from one end of the granulation drum is conveyed to the double-layer screening machine using the intermediate product bucket elevator. A small quantity of ultra-large granular urea, separated by the top screen, is directed straight to the collection tank on the ground floor. Meanwhile, the small granular urea filtered out by the bottom screen flows through a chute back into the granulation drum to act as seed crystals. The ultra-large granular urea is available for separate sale. The large granular urea that passes through the two screens meets the design specifications and is then sent via a chute to the drum cooler to be cooled to ≤50℃. After cooling, it is transferred to the finished product belt conveyor packaging system for packaging and subsequent dispatch.

3. Technical Advantages

1) Adopting dual collaborative process of rotating drum pre-granulation + fluidization shaping, the particles grow by being coated layer by layer from the inside out, with high sphericity and uniform particle size distribution (CV value <8%). The crushing strength is 5 times that of conventional fluidized bed products, the moisture control accuracy is ±0.3%, and there is no risk of excessive biuret. The particle size can be flexibly adjusted within the range of 2-8mm to adapt to different fertilization scenarios.

2) Relying on the low-pressure fluidizing air design and the synergistic utilization of heat from the rotary drum and fluidized bed dryer, energy consumption is reduced by more than 1/3 compared to conventional fluidized bed dryer; the entire set of equipment is domestically produced, and the investment cost is reduced by 30%-40% compared to similar technologies.

3) We support both planar and frame layout plans. For projects with a capacity below 200,000 tons per year, a planar layout can be adopted to save 5-10% on investment. For those exceeding 300,000 tons per year, a frame layout helps reduce land usage, making it ideal for both new installations and upgrades of existing facilities. The drum features an built-in settling chamber and a two-stage tail gas scrubbing system, ensuring a high dust recovery rate, compliance with tail gas emission standards, no secondary pollution, and eliminating the need for complex dust removal equipment.

4. Technical Benefit

1) Due to its high particle strength, low dust content, and resistance to clumping, the loss during transportation and storage is reduced by more than 60%. It is also suitable for mechanized fertilization and slow-release fertilizer coating processing, and the product can achieve a market premium of 5%-10%. At the same time, the batch consistency is ≥98%, which meets the needs of high-end agricultural and industrial applications and significantly enhances market share.

2) Investment costs are reduced by 30%-40% compared to conventional fluidized bed dryer, construction period is shortened to 4-7 months (far lower than conventional process), capital occupation costs are reduced; energy consumption is reduced by more than 1/3, steam and electricity consumption per ton of product is significantly reduced, coupled with fewer vulnerable parts and simpler operation and maintenance, long-term operating costs are reduced by 25%-30% compared to traditional process, investment payback period is shortened by 1-2 years.

3) It can easily adjust to meet various production capacity requirements, ranging from 50,000 to 600,000 tons annually. When renovating existing plants, there's no need to add new granulation towers, and for new projects, existing sites can be fully utilized. The entire process operates in a sealed environment with a design that minimizes dust, ensuring compliance with environmental emission standards without the necessity for investing in additional, costly exhaust gas treatment equipment. It boasts a lengthy continuous operation cycle and experiences minimal unplanned downtimes, achieving a capacity utilization rate that is 10%-15% higher than that of conventional fluidized beds, thereby offering enhanced production stability and better policy adaptability.