Preheater & Calciner basic | Type of Preheater | Pyroprocessing | Cyclone

Preheater is an equipment to extract heat from the kiln gases to PRE- HEAT the raw material before being fed in to kiln.

Raw material is preheated to Calcination temperature in the Preheater.

Cyclone is cylindrical vessel with a conical bottom and a slightly enlarged top with entry for dust laden gas and exit for gas at the top and dust at the bottom.

Type of Preheater:

1. SP – Suspension Preheater
2. ILC-E (In Line Calciner Using Execess air)
3. ILC - Single, twin or 4 String
4. SLC - Separate Line Calciner
5. SLC-I (Separate Line Calciner with inline calciner)
6. SLC-D (Separate Line Calciner with Downdraft)
7. SLC-S

1. The first cyclone Preheater patent is develop on 25-July-1934 by Mr. M Vogel Jorgensen (FLSmith Empolyee).
2. Cylone preheater put in operation in 1951 by Mr F. Muller (KHD)
3. Heat Transfer is in Counter Current and 0.1 mm Limestone takes 0.1 second time at ~ 515 °C.
4. The pressure drop of a cyclone raw mix suspension Preheater is in range of 55-60 mbar.
5. Dust load of exit gas is about 80-115 gm/Kg of clinker, average 10% of clinker weight.
6. Exit gas volume is 1.4-1.5 st.M³/Kg of clinker.
7. 80% of heat Transfer is in Riser duct and 20% Heat transfer in Cyclone. Prove by Mr. Spassky of Soviet Cement Plant.
8. By 330 °C gas temperature is dry the raw material with upto 8.5% of moisture.
9. Preheater retention time upto 50 mtr length is 25 sec (Till Kiln Inlet)
10. Riser duct Gas velocity 20-22 m/sec.
11. Kiln L\D ratio (length by diameter) is appox 14: 1

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