spray granulation dryer for NPK phosphate granular FERTILIZER PRODUCTION LINE

What are the kinds of phosphate fertilizer spray granulation dryer?

In the production of phosphate compound fertilizer, the granulation equipment used in several commonly used granulation methods is as follows. For agglomeration and slurry coating granulation methods, there are spray granulation dryers, drum granulators, biaxial granulators, disc granulators, etc. For melt condensation granulation method and there are spray drying tower. For extrusion granulation method, there is extrusion granulator. But in this article we are going to introduce about the most important equipment which is the rotary drum phosphate feritlizer spray granulation dryer.

Fertilizer production line equipment: Spray drum granulator&dryer

What is spray drum granulation dryer structure?

• The spray granulation dryer is a device that combines granulation and drying in a rotating cylinder to complete the production of granular fertilizer in the presence of returned materials. There are two rolling rings outside the carbon steel cylinder, which are supported on the front and rear supporting wheels respectively. A wheel block is installed on the rear end supporting wheel to prevent the axial movement of the cylinder.

What is the transmission part of the spray drum granulation dryer?

• The spray granulation dryer its cylinder is installed obliquely on the foundation; a large gear is installed on the cylinder near the right end of the supporting wheel. It meshes with the small gear of the driving device and is driven by an electric motor through a reducer, thereby driving the cylinder to rotate.

What is the supporting part of spray drum granulation dryer?

• The two ends of the spray granulation dryer cylinder extend into the fixed inlet and outlet boxes and are sealed by sealing devices. The return pipe extends from the top of the feed box into the interior of the cylinder, and the hot air inlet pipe is introduced from the side of the box, so that the incoming air is evenly distributed over the entire dryer section. The slurry spray gun is inserted into the cylinder from the end of the feed box. There is an exhaust pipe at the top of the discharge box to discharge dusty exhaust gas.

How many chambers are inside the spray drum granulation dryer?

• Answer: There are 4 chambers Inside of the spray granulation dryer. The cylinder is divided into granulation area, drying area, plate-free area and screening area. There is a spiral guide plate at the front end of the granulation area to push the returned material evenly and quickly into the barrel. The subsequent granulation area and drying area are equipped with multi-stage lifting lifting plates. When the cylinder rotates, the picked up materials are evenly distributed to form a dense material curtain. The granulation and drying zones are separated by a retaining ring, so the filling factor of the granulation zone should be slightly larger. The purpose of setting up the non-lifting plate area is to avoid the flying of dust and reduce the material being carried out by the air flow of the spray granulation dryer.

What is the screenig part of the spray drum granulation dryer?

• The screening area is equipped with mesh bars to separate large pieces of material larger than 40mm. The outer wall of the end of the cylinder is equipped with a hammer device, which can knock down the bonding material on the inner wall of the cylinder as the cylinder rotates. The nozzle of the slurry spray gun usually adopts an airflow type and a two-flow atomization structure.

How to calculate the RMP of spray drum granulation dryer?

• Due to high production capacity  of the spray granulation dryer and good physical, chemical and mechanical properties of the finished product, the shotcrete granulation dryer has been widely used in the production of ammonium phosphate by slurry concentration method. Its volumetric evaporation intensity is 15~20kgH2O/(m3·h), and the appropriate filling factor is 15%~20%. The optimal rotation speed can be calculated by the following formula: 
• n=60v/πd

n—— is the rotation speed of the dryer, in r/min; 

v—— is the residence time of the material in the dryer, in min; 

D—— is the inner diameter of the dryer (that is, the average distance of the material in the dryer), The unit is m; 

π—— is pi, which is approximately equal to 3.14.

Fr——The best Froot accuracy number; can be selected from 0.021 to 0.023;

G——gravitational acceleration, 9.81m/s2

What is the return system of the spray slurry granulation dryer?

The return ratio of the spray granulation dryer granulator is generally 4 to 6. In order to reduce the number of external return materials, the former Soviet Union developed a C-type internal return spray granulation dryer in the 1970s. Its characteristic is that a truncated cone inner cylinder with an included angle of 35° is set up at the rear of the drying area as a grading device for internal particles. The fine particles that have overflowed the large particles after classification are returned to the dryer head through a reverse spiral channel set on the inner wall of the cylinder, and are sent into the cylinder by the spiral copying plate. In this way, the external return ratio can be reduced to about 0.5, and the granulation rate can reach 80% to 90%.

How to install a spray drum granulator&dryer in 5 steps?

1. The installation of spray drum granulation dryer is slightly different from that of ordinary drum equipment, but it is basically the same. First, the concrete pouring of the foundation part is carried out. When the foundation is completed, tongli engineers will carry out foundation size acceptance.
2. After all dimensions are accepted, the spray drum granulation dryer foundation is hoisted. Two 20t cranes are used to lift the base frame and supporting wheels to the designated position, and the positioning is confirmed again.
3. After the positioning is confirmed, perform secondary grouting of the foundation, place the anchor bolts into the base positioning holes of the spray drum granulation dryer, wait until the 3-day concrete period has passed, and then use the installation pads to adjust the position.
4. After the chassis is installed, the next step is to install the cylinder. Use two 40t cranes to lift the cylinder to the chassis. After installation, install the large gear and wheel belt.
5. The above is the installation sequence of spray drum granulation dryer. Of course, this is just a simple installation process. Tongli has more detailed installation specifications.

Who is Tongli Heavy Machinery? Answer: Tongli is the No.1 fertilizer equipment supplier in the industry