Height of the granulation tower and insulation type of the pipelines leading to it

The height of the granulation tower is related to the design capacity of the urea plant. Once the installation is completed and the granulation tower is put into use, its height will no longer be related to the production load, nor can its height be reduced. Here, the insulation steam used for the companion pipes in the granulation pipeline is generally at 0.21~0.24 MPa, with the three companion pipes arranged at 120 degrees to each other.

Our granulation line also uses jacketed heating. The height of the granulation tower is 98 meters

The height of the granulation tower is related to the design capacity of the urea plant; generally, a plant with a capacity of 180,000 tons requires a tower that is 70 meters high. A pressure of 0.3 MPa for the insulation steam is considered appropriate.

The height of the granulation tower is generally not closely related to the capacity of the urea production plant; rather, it is closely associated with the local annual maximum temperature. Its height must be such that the urine sprayed from the nozzles can cool down and turn into solid particles, and the temperature of these particles must meet the requirements for packaging. In the northern part of our country, the annual maximum temperature in summer is similar to that in the south; therefore, the height of the granulation towers in urea plants across the north and south is roughly the same, at around eighty to ninety meters. Related to the capacity of the urea plant is the diameter of the granulation tower; the greater the capacity, the larger the diameter required. The number of insulation sleeves depends on the local annual minimum temperature; lower temperatures require more sleeves, and the purpose of this is self-evident. This post was last edited by Doorway Lion Dancer on 2009-2-5 10:00.]

Our company’s granulation line also uses steam heating； The effective height of the granulation tower is 64 M.

If a fluidized bed granulation system is used, by how much can the height of the granulation tower be reduced? In the long run, which of these two methods results in lower costs? ?

Generally, it depends on the geographical location; our factory is situated in a hilly area, so the tower is quite tall – 98 meters high. In flat areas, the towers can be shorter. For insulation of the tower, jacketed insulation is usually used, which is more expensive but offers better results. Steam supply is generally stopped after granulation, as this helps to reduce the formation of dicyandiamide. The steam used for insulation is depressurized steam at 0.28 MPa.

If large-grained urea is to be produced using a fluidized bed, it is better not to install a granulation tower; there is no need for such an additional investment. In terms of granulation cost, the granulation tower is lower than the fluidized bed.

The size of the granulation tower (effective height and diameter) depends on the capacity of the installation, but there are two key principles: 1: The particles that fall to the bottom of the tower must be able to cool down during the period of highest local temperatures； 2: It can still cool down under maximum load. Jacketing is generally used for insulating the upper tower pipelines; the steam pressure is 0.28 MPa. A dedicated pressure reducing valve is included in the process design to control this steam, but it is usually not used in southern regions!

Our granulation line also uses jacketed heating, with the insulation steam pressure controlled at 0.25 MPa; the height of the granulation tower is 60 meters.

The effective height of our newly installed granulation tower is 78m. I would also like to know that many small and medium-sized nitrogen fertilizer manufacturers have adopted a pre-mounted fluidized bed together with a dust recovery system at the top of the tower; it is said that this approach yields good results and brings financial benefits. Is that true? ?

The combination of a granulation tower with a fluidized bed yields very good results

During the renovation of old equipment, such modifications can be carried out as a last resort. Everyone says it works well, but it’s hard to say exactly how good it is. Those who are aware of the situation please share their insights.

1. It is better to use saturated steam in the granulation pipeline, with the pressure controlled at around 0.25–0.29 MPa. 2. It is advisable to use a double-walled tube for the granulation pipeline. 3. The height of the granulation tower is determined primarily by the highest summer temperature in the area; this height determines the time required for the particles to fall, and this time is the period during which the particles are in contact with air for heat transfer ； But it is also related to factors such as production load and the geographical location of the tower. 4. The production load ensures the temperature rise rate during the air ascent process. 5. The geographical location ensures an adequate air flow at the intake opening (louver). Additionally: The combination of a granulation tower with a fluidized bed works very well. May I ask which manufacturers are using it?

Small and medium-sized nitrogen fertilizer plants are used extensively; the largest capacity of such plants in operation at present is around 1200 t/d. It is said that Sichuan Tianhua is working on expanding its facilities! This post was last edited by Fan Zhou Wu Hu on 2009-3-9 at 17:44

Is the steam from your plant not in use? Will it still not be put into use in the summer? Has crystallization occurred?

There are two prerequisites for not using steam: 1, the granulation pipeline is insulated with a jacket; 2, normal production is in progress. And it’s not limited to summer; you can also refrain from planting in winter. Since the jacket provides good insulation, it can easily lead to excessive levels of biuret, which is why many companies do not use it during normal production. To control product quality, this involves a certain degree of risk. Care must be taken during operation; as long as it is controlled properly, the operation can be carried out successfully. Precautions: 1. After closing the jacket insulation steam valve, be sure to drain the water. There should be no liquid accumulation either before or behind the valve. 2. During the evaporation cycle or when the system is shut down, it is essential to quickly open the jacket steam to allow the condensate to be discharged promptly. 3. Drain the granulation pipeline in a timely manner during normal shutdown.

Fluidized bed granulation can be used throughout the seasons; could this help reduce costs while still ensuring the quality of the finished products?

The granulation line in our factory is equipped with a jacket for insulation; the steam used can be of either medium or low pressure. However, whether it’s winter or summer, the insulation steam is generally not turned on – it is only activated at the beginning of the granulation process, and once normal operation is achieved, the insulation steam is turned off immediately. There has never been any blockage of the pipes. The granulation tower is equipped with a fluidized bed, which primarily serves to cool the material and remove dust; it has little impact on reducing consumption. Installing a acne recovery device at the top of the granulation tower can help reduce energy consumption and emissions. This post was last edited by Boating on the Five Lakes on 2009-3-11 22:50.]