Rotary Kiln Burner Lance Cooling Water Integration

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Solution Overview

Problem

The production of white cement requires higher energy input and complex process control due to the need for intense and rapid quenching of cement clinker, which can lead to discoloration and hydraulic reactions, and existing methods are not robust or operationally reliable.

Innovation Solution

Integrating a cooling water line into the burner lance of a rotary kiln, allowing for simultaneous heating and cooling, which improves control over the reductive atmosphere and reduces thermal stress on the burner lance, thereby extending its service life and maintaining a stable reductive environment for producing high-quality white cement clinker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If cooling water is supplied into the rotary kiln for quenching the sintered cement clinker, then the quenching speed is improved, but the reductive atmosphere is compromised and discoloration occurs

Engineering Contradiction:
Improvequenching speedVSAvoiddiscoloration
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The rotary kiln is divided into distinct functional zones: a sintering zone where clinker is formed under reductive atmosphere, and a quenching zone where cooling water is introduced to rapidly cool the clinker. This spatial segmentation allows the reductive atmosphere to be maintained during sintering while enabling rapid quenching without compromising the atmospheric conditions that prevent discoloration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A water spray system acts as an intermediary mechanism to introduce cooling water into the kiln in a controlled manner. The water is sprayed onto the hot clinker in the quenching zone, serving as a heat transfer medium to achieve rapid cooling while the overall kiln atmosphere remains reductive, preventing oxidation and discoloration of the clinker surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If high sintering temperature is used for white cement production, then the desired clinker phases are formed, but energy consumption increases significantly

Engineering Contradiction:
Improveclinker phase formationVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The chemical composition of the raw materials is carefully controlled and optimized to include specific mineralogical compositions that enable sintering at slightly lower temperatures compared to conventional Portland cement production. This parameter optimization in the raw material composition allows the formation of desired clinker phases (C3A, C2S, C3S, C2SiO2) at reduced energy input while maintaining the required manufacturing precision for white cement quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sintering process utilizes controlled phase transitions and crystallization of calcium aluminate and calcium silicate phases. By optimizing the heating rate and holding temperatures, the process achieves complete phase formation with minimal energy input, leveraging the thermodynamic characteristics of the cement chemistry to reduce overall energy consumption while maintaining high manufacturing precision.

Inventive Principle:
Principle #36Phase transitions

3Manufacturing precision

If rapid quenching is applied to prevent discoloration, then clinker quality is improved, but hydraulic reactions occur on the clinker surface

Engineering Contradiction:
Improveclinker qualityVSAvoidhydraulic reactions
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The quenching process is applied locally and selectively to the surface layer of the clinker granules, rather than uniformly throughout the entire mass. The water spray is directed to cool only the outer surface rapidly, creating a hardened crust that prevents hydraulic reactions, while the interior of the granules maintains higher temperatures and remains free of unwanted chemical reactions. This localized quality approach ensures clinker surface integrity without triggering bulk hydraulic reactions.

Inventive Principle:
Principle #3Local quality

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 solution reduces energy consumption, enhances the robustness and reliability of the process, and ensures the production of high-quality white cement by effectively controlling the cooling and reductive conditions within the rotary kiln, preventing discoloration and hydraulic reactions.

Implementation Method 1

a burner lance is provided at the rotary kiln head of the rotary kiln for generating the necessary sintering temperature in the rotary kiln

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

at least one line for supplying cooling water into the rotary kiln for quenching the sintered cement clinker while still in the rotary kiln

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

a much more intensive and rapid quenching of the sintered cement clinker is also required to ensure the formation of the desired, colorless clinker phases

Methodology Applied
Scientific EffectRapid cooling: Cooling

Implementation Method 4

a highly reductive atmosphere is also necessary during sintering

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3775742B1System and burner lance for additionally producing white cement
Publication Date: 2023.07.12 KHD HUMBOLDT WEDAG GMBH
  • EP3775742B1 patent drawingFigure 1~2
  • EP3775742B1 patent drawingFigure 3

AI summary

The invention relates to a system for producing a cement clinker for the additional production of white cement, having a rotary kiln (15) for sintering lime-containing and silicate-containing raw meal (35) and optionally additional oxide in order to form the cement clinker (45), wherein a burner lance (25) is provided on the rotary kiln head (40) of the rotary kiln (15) in order to generate the necessary sintering temperature in the rotary kiln (15), and the burner lance (25) reaches into the rotary kiln (15). The system also has at least one line (110) for conducting cooling water (110) into the rotary kiln (15) in order to quench the sintered cement clinker (45) still in the rotary kiln (15). According to the invention, the burner lance (25) has at least one line (110) for conducting cooling water, and the line (110) for conducting cooling water opens in the region between the burner opening and the end of the rotary kiln head (40) and sprays cooling water onto the sintered cement clinker (45). By integrating the burner lance with the cooling water line, the burner lance is cooled and simultaneously the reductive conditions in the rotary kiln can be controlled more easily upon quenching.