Equipment and Process Functions in the cementing industry - part (2)

Course Outline

1 – Preheater with Precalciner.

•    How it works.
•    Its construction.
•    Raw material and Gas circulation.
•    Sensors’ locations.
•    Temperatures and Pressures.
•    Reasons for the disturbances in gas or material flow & temp.

 
2 – How the Load advances in the Kiln.

•     The rotary kiln slope.
•     Types of process that affect the Kiln speed.
•     System without Precalciner:
  • The function or role of released CO2 in the kiln.
  • What’s the Risk?
  • The speed of the Kiln.
•     What is meant by Peripheral Speed?
•     Calculation of Peripheral Speed of Kiln?
•     Relation between peripheral speed & load angle?
•     Outer Diameter, Load Angle & the Kiln Torque.
•     What upsets material speed in the kiln.
•     Constant Material bed in kiln.
•     Kiln Percent Filling Degree.
•     Calculation of the Filling Degree.
•     Consequences of an Impinging Flame on the load.
•     Bed Thickness.
•     Kiln Speed/ Kiln Feed ratio.
•     Kiln Gases Speed.

3 – Burning Zone.

•     Length of Kiln = 15 * Kiln Diameter.
•     The 2 main Zone of Rotary Kiln.
•     Exothermic & Endothermic reactions.
•     Ignition Point.
•     Factors influencing the Length of the Zones & Time of Reaction.
•     Parameter that would alter the length of the burning zone.
•     Factors changing the Burnability.

4 – Coating Formation.

•   The Crust, where it comes from & reasons for its variable thickness.
•    The Load, the load angle, an indicator of the burningstate, how it affects kiln absorbed power.
•    Kiln Power, a picture of the burning zone clinkering. Process, and of the quality of the burning.
•     The purpose of the Shell Cooling Fans.
•      Formation of the Coat.
•     Characteristics of Burning Zone Refractories.
•     Liquid Phase calculations.
•     Minerals affect the viscosity of Liquid Phase.
•     Factors affect the Thickness of the Coating.
•     Recommended thickness of Coating & excessive Coating.
•     The 2 Critical places for Ring Formation.
•     The 3 possible Causes for Coat LOSS & temp. peaks.
•     The angle of the Load in the Burning Zone.
•     Kiln motor Intensity.
•     Factors affect the Torque of the kiln.
•     Torque Requirement = Kiln Heat.

 
5 – Kiln Heat Exchanges

•     Types of Heat Transfer.
•     Heat sources.
•     Combustion.
•     Radiation, Convection and Conduction.
•     Flame Radiation (Heating of Coating + Brick).
•     Conduction + Material mixing = Heating up of LOAD.
•     Factors determine the Quantity of Heat radiated.
•     Shell Losses.
•     Causes for shell losses.
•     Variations of Flame temperature.

 
6 – Refractories

•     The fundamental of Refractories
•     Definition of Refractory.
•     Refractory Applications.
•    Role of Refractories.
•    Factors require appropriate lining of the kiln.
•    Constraints during Clinker production.
•    Main Characteristics of good Refractories.
•    Classification according to Physical properties.
•    Fabricated & non-Fabricated refractories.
•    Refractory linings and their places.
•    Types of Bricks according to Chemical Composition:
  • Silica.
  • Alumina.
  • Magnesia-Chromite.
  • Dolomite.
•     Their thermal conductivity, Porosity & Ch. Comp.
•     Characteristics of the 4 most used types.

7 – Cooler Heat Exchange.

•    Heat exchange after the Burning.
•    Cooling of Clinker.
•    Preheating of the Combustion air.
•    Reasons for Clinker Cooling.
•    Purpose of Clinker Quenching.
•    False set.
•    Clinker nodule cooling mechanism.
•    Effective Heat Exchange depends on:
  • Clinker quantity.
  • Clinker temp.
  • Air flow.
  • Surface area.
  • Particle size.
  • Bed thickness.