Cement Preheater Tower Height Reduction via Bypass Segmentation

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Solution Overview

Problem

Cyclone preheaters in the cement industry face high construction costs and inefficiencies due to the need for tall structures to accommodate worst-case scenarios of cyclone filling and maintain high production rates at high temperature differences, which are exacerbated by the weight of material and suboptimal heat exchange.

Innovation Solution

A multi-stage cement calcining plant suspension preheater design featuring a top separator with a central tube entering the lower part of the housing and bottom separators with central tubes entering the upper part, along with a centrally arranged material feed inlet, optimizing separation efficiency and heat exchange by reducing the height of the preheater tower and minimizing worst-case filling weights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the preheater tower is dimensioned to accommodate worst-case scenarios of cyclone filling, then the reliability is improved, but the weight of stationary object increases

Engineering Contradiction:
ImprovereliabilityVSAvoidweight of stationary object
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies preliminary action by providing a bypass connection that allows material to be diverted away from the cyclone separator before it can fill up completely. This preventive measure ensures that even if the outlet becomes blocked, the material can still flow through the bypass, preventing the worst-case scenario of complete cyclone filling and avoiding the need to dimension the tower for maximum possible weight

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bypass connection acts as an intermediary pathway between the material feed inlet and the outlet. When the outlet is blocked, this intermediate route allows material to still pass through the separator housing, preventing complete filling and reducing the weight burden on the tower structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the preheater tower height is increased to maintain high production rates at high temperature differences, then the productivity is improved, but the length of stationary object increases

Engineering Contradiction:
ImproveproductivityVSAvoidlength of stationary object
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The patent segments the material flow path by introducing a bypass connection that creates an alternative route through the separator housing. This segmentation allows the system to maintain efficient heat exchange in the cyclone while providing a backup path, enabling shorter tower designs that still achieve high productivity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass connection introduces a new dimensional aspect to the flow path by creating a parallel route through the housing. This additional flow dimension allows the system to achieve the required heat exchange and productivity without proportionally increasing the tower height

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enhances separation efficiency to 91-95% and reduces construction costs by lowering the height of the preheater tower, allowing for increased capacity or reduced cyclone stages while maintaining production rates, and improves heat exchange through counter-current flow patterns.

Implementation Method 1

a cyclone preheater comprising four to six cyclone stages is used arranged in a preheater tower construction. The raw meal is introduced in the first cyclone stage and heated by direct contact with hot exhaust gases from the kiln according to the counter flow principle.

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

The raw meal is introduced in the first cyclone stage and heated by direct contact with hot exhaust gases from the kiln according to the counter flow principle.

Methodology Applied
Scientific EffectCounter-current heat exchange: Heat Exchanger

Data Source

PatentEP3359899B1Multi-stage cement calcining plant suspension preheater
Publication Date: 2020.08.05 F L SMIDTH & CO AS
  • EP3359899B1 patent drawingFigure 1~2
  • EP3359899B1 patent drawingFigure 3
  • EP3359899B1 patent drawingFigure 4

AI summary

The invention relates to multi-stage cement calcining plant suspension preheater of the kind mentioned in the introduction, wherein the preheater comprises a top separator comprising a central tube entering the top separator in a lowermost part of the separator housing whereas the central tubes of the bottom separators enters the separator housing in an upper part of the separator housing.