Ph5110.020 r00 Preheater Description

Type of document:

PREHEATER PREHEATER ERECTION AND OPERATION MANUAL Designation:

PREHEATER DESCRIPTION No. of document:

PH5110.020

R00 Edition

2009.08.15 Date

First issue   Notes

2009.08.15

Deng Yuhua

Liu Zhijun

 Au thor th or

Checked Chec ked

Tao Ying Ap prov pr oved ed

Content 1

Usage..........................................................................................................................................................1

2

Working Principle ........................................................................................................................................1

3

Structure of preheater components ............................................................................................................2

1

Usage The preheater system is applied to complete the preheat of raw meal and decomposition of the

calcium carbonate. The decomposition rate of raw meal before kiln can amount to 90 . The heating-up process, operation and shut down of the plant shall be carried out in compliance with the process engineering provisions. The special start and stop procedures must be observed, in particular safeguarding of all plant sections through electric interlocking and emergency disconnections shall be ensured. The necessary checks and supervising activities shall be carefully implemented. The preheater must only be operated in perfect condition, e.g. only with complete refractory lining as well as closed and safeguarded inspection and cleaning openings.  Any use beyond the above scope is considered not to be in accordance with the intended application. CBMI will not be liable for any damage resulting from such inappropriate use. The risk will be solely by the user. Inappropriate use of preheater plants involves dangers that may cause serious personal injury and damage to property. 2

Working Principl e This preheater system is composed of a single/double series of preheater and on-line precalciner.

Fuel and preheated raw meal entered into calciner are taken by high-speed current of air, suspend in precalciner inside, go upside in flow and fire and resolve at same time. The combustion of the fuel gives out heat and the raw meal absorbs heat to decomposition. These two processes happen very quickly at the same time in suspended condition. The CaCO 3 decomposition of raw meal has already completed before going into the kiln. Raw meal fed from the gas duct connecting C2 outlet and C1 inlet flows into C1 and carry on to be heated with the hot gas in advance. The preheated raw meal pass C1 chute into the gas duct connecting C3 outlet and C2 inlet, and then flows into C2 and separate from hot gas again. The meal passes C3 an d C4 by analogy. Passing C4 raw meal enters into the precalciner and then enters C5 with high temperature kiln gas and tertiary air, at last passes C5 chute into the kiln. Raw meal gets down and its temperature increases gradually while exchanging heat with hot gas flow. Gas go upward and exchange heat with raw meal while its temperature declines gradually and at last ventilate from C1 outlet. If raw meal contains large quantity of alkali and sulfur, By-pass ventilation system shall be adopted to keep normal operation and qualified clinker product.

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Structur e of preheater compo nents This preheater system is composed of cyclone, gas du ct, meal chute, precalciner (DD fur nace), inlet

chamber and starting c himney (bleed-in damper).  All cyclones are of welded steel plate structure of low resistance and supported on the floor of a preheater tower, immersion tube is established inside at cyclone outlet, in order to installation and replacement, The immersion pipes of cyclone stage 2nd to 5th are divided into segments. Gas duct is supported on the floor of a preheater tower, its top (outlet) is welded with a cyclone inlet, and its bottom is welded with lower cyclone outlet after the pre-lifting of lower cyclone roof. These welding shall be carried out at site during preheater erection. The splash box welded at lower part of gas duct is to connect superior meal chute. The DD furnace is of welded steel plate structure and supported on the floor of a preheater tower. The DD furnace is cylindrical type and consists of a lower combustion chamber, a middle mixing chamber, an upper mixing chamber and two intermediate orifices between each chamber. The lower combustion chamber shall be welded with middle mixing chamber, the upper mixing chamber connects with milldle mixing chamber by means of expansion joint. Each chute is flanged to the apex of conical part of a cyclone. Pendulum flap valve is provided to each chute which prevents the rising gas from flowing up by short circuit through the chute. Inlet chamber is of welded steel plate structure and supported on the floor of a preheater tower. It acts as a path for precalcined raw meal and kiln exit gas between rotary kiln and DD furnace. Bleed-in damper is provided on gas duct between the first and second stage cyclones and as an air including duct in case of abnormal temperature rise. Inner surface of all components are lined with refractory brick and insulation board.

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