PREHEATER TOWER

Achieve capacity and energy benefits in your preheater.

The design of the preheater system is a major factor for efficient cement production. Its design and complexity have evolved rapidly thanks to growing production volumes and increasing energy costs.

Today’s dry process kilns, coupled to multiple-stage preheater systems, offer 20 times more capacity than similarly sized wet-process kilns. The thermal efficiency and capacity of a modern cement-making operation is very high – but can be even higher with the right refractory solutions.

In this section, we deal specifically with the following areas of the preheater tower:

Cyclone – Gas ducts – Meal pipes

Click to enlarge

The objective of the cyclone system is to support greater thermal efficiency, and greater kiln capacity. Höganäs Borgestad has developed refractory solutions that allows you to:

• Operate under increasingly high temperatures
• Withstand the chemical attack of alkalis, chlorine, sulfur and transition metals
• Meet the construction requirements of ever-larger cyclone units
• Provide the smooth, non-wetting surfaces that support optimal airflow and reduce or eliminate build-ups

Our refractory solutions are listed on the table below:

Calciner – Riser duct

Click to enlarge

Due to higher operating temperature, chemical attack is a more severe problem in the calciner than in the cyclones. High refractoriness and good resistance to thermal shock are also necessary, especially around the burner blocks.

In the lower, hotter part of the preheater system, chemical influences are the cause and can affect both straight and curved duct sections. Riser duct connected to calciner suffers often from build-up problems. In riser ducts connected to cyclones, build-ups are usually caused by a venturi effect. This occurs mostly in the curved sections of the duct. The closer the duct is to the ’hot’ end of the preheater system, the greater the risk of alkali penetration and refractory spalling. Where alkalis have penetrated to a depth of 20-30 mm, the refractory can expand 10 times more than normal, causing spalling. If this process is allowed to continue, the wall could collapse. To keep alkaline vapor from condensing, the amount of insulation should be reduced.

Our refractory solutions are listed on the table below: