Minntac Agglomerator Process Description

Review the files in the below order.

1. Agglomerator Presentation.ppt

a. General Overview of the entire Agglomerator process

2. Agglomerator Overview.pdf

a. Process Flow diagram of the Agglomerator process

3. S3 Isometric.jpg

a. Overview of how the equipment is laid out in the Step 3 Agglomerator building. It also 

provides relative sizing of the equipment involved in the agglomerator process.

The above three files is a general overview of the Agglomerator process. The files below will go over 

indurating process and the low NOx burners.

4. Step 2 Grate Kiln with Airflow.pdf (page 1)

a. Process Airflow is key to the indurating process. The diagram shows that airflow runs 

against the flow of the pellets. 

i. Traveling Grate:

1. In the DD1 (down draft) section of the grate, the green balls are dried. 

The airflow from the preheat section of the grate is pulled into DD1 and 

the air temperature of DD1 is approximately 600oF. The air is pulled 

through the DD1 section by the waste gas fan.

2. The green balls continue to increase in temperature in the DD2 section. 

When making flux pellets, the calcinations reaction (endothermic)

starts. The air temperature in the DD2 section is approximately 1400oF. 

The DD2 section heat is obtained from the cooler recoup air. The air is 

pulled through the DD1 section by the waste gas fan.

3. The air temperature in the preheat section is approximately 2200oF. 

The preheat section is heated using low NOx preheat burners and air 

from the kiln. In the preheat section, the greenballs complete the 

calcinations reaction and start the oxidation reaction (exothermic). The 

air is pulled through the preheat section by the 1A and 1B fans (which is 

then put into DD1).

a. Pre heat burners:

i. Line 3 – 8 burners

ii. Lines 4-7 – 14 burners

ii. Kiln

1. The kiln can be heated by the following fuels:

a. Natural Gas

b. Biomass

c. Fuel oil

d. Coal (only Line 6 and 7)
2. At the end of kiln, the pellets are heated to approximately 2300o

F.

iii. Cooler

1. Pellets are dumped from the kiln into the annular cooler. Outside air is 

pushed upward through the pellets with the 3A and 3B fans. The air 

from the 3A fan goes into the kiln through the lineal flow duct. The 

temperature of this air is approximately 2000oF. The air from the 3B fan 

goes into the DD2 section of the grate. 

b. General process comments

i. The process is run negative. This is to ensure that no process gas is released in 

the plant and also for safety reasons as the process air temperature is very hot.

The general idea with a low NOx burner is to add combustion air (outside air) to reduce the temperature 

of the flame which then reduces NOx. The addition of combustion air affected the airflow balance on 

the line. The waste gas fan removes air from the process and before the low NOx burner was installed, 

it was running at 100% capacity. Therefore, the waste gas fan capacity was increased in order to be able 

to exhaust the additional air that was added. 

5. Line 6 and 7 Kiln area 3D model.pdf

a. This file is a working model that is to scale. Left click and drag to rotate the drawing. 

Right click and drag to zoom in and out of the drawing.

b. When opening the file, you will see kiln and associated equipment for Line 6 and 7. Line 

6 is located on the right side and line 7 on the left side.

c. For the Line 6 burner, an extension was made to the building (building is located above 

the pink colored roof). Currently, this building houses two blowers which are used on 

Line 6. In the future, an additional fan will be for Line 7. With this layout, the 3 blowers 

will supply the air for both Line 6 and 7 (one blower running for each line and on spare 

swing fan that could be used for either line). The dimensions of the building are 40’-6” x 

39’-2” x 26’ tall.