Industrial Experiment On Novel Process Of Granulation Of Urea-Based Compound Fertilzer

The usage of urea is still the largest among fertilizers in China. But recent years, as the rapid development of Chinese modern agriculture, the consumption of fertilizers have changed from single nutrient fertilizer trend to compound fertilizers. According to the progress of the world fertilizer, compound fertilizers have played more and more important roles in fertilizer industry. The production technologies of compound fertilizers and the consumptions have become one of the indicators of a country's fertilizer industry development condition and applying principle level. So, fertilizer manufacturers devoted their techniques and money to produce compound fertilizers, Special for urea-based compound fertilizers production due to its high concentrate nutrients. The topics of the investigations focused on process and scale of plant, especially on fluidization granulation process of urea-based compound fertilizers.This paper industrial experimented on novel process of granulation of urea-based compound fertilizer with a 2000kt/d TEC granulation unit which by revamped based on the pilot study of granulation of urea-MAP compound fertilizer. The experiments include two stages. In the first stage of closed circuit, the heat balance of granulator, the shape of granulated product and the status of fluidizedbed were tested when operation style changes from batch to continuous. Certain data were determined like the depth of coating layer, the distribution of the diameter of articles and the changes of the physical properties of product and so on by being analyzed the granulated product. In the second stage of open circuit, the alternatives were made to match the demands of the continuous process, such as the alternative of the control indicator, the innovations of the process, the filtration of the articles and other back treatments. After the treatments, good diameter contributions of articles were obtained, and the N: P2O5 ratio can be adjustable. No grown up articles and additional added articles were returned back to granulator recycled to make continuous process of experiments.The experiments result shown that industrial produce of urea-based compound fertilizer by using MAP as the granulation core is feasible. The most suitable temperature of fluidized bed should be controlled between 50 and 60 . Pressure nozzle should be selected with aperture of 2.5mm. The fluidizing air flow rate should be controlled about 3m/s. The pole of sieve should be chosen as about 3mm of under layer and 5mm of super layer. The fluidized bed should be chosen as rectangular type, the nozzle should be lay out with in a triangle; the diameter distribution of core should be chosen as narrow as possible to decrease the dust, which needed to deal with by circulating washing solution; The N: P2O5 ratio of the nutrients can be adjusted by adjusting the materials.