Vertical Ring Shaft Kiln Homogeneous Heat Distribution
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Solution Overview
Problem
Conventional vertical shaft kilns suffer from low sintering efficiency due to uncontrolled burning zones and limited production capacity, resulting in high amounts of low-quality material and unburned products, which has led cement producers to prefer rotary kilns.
Innovation Solution
A vertical ring shaft kiln design with a vertically oriented intermediate sintering zone defined by first and second walls, where the gap between these walls is configured to ensure homogeneous heat distribution through a predetermined distance, using fuel-bonded raw materials and external burners to maintain temperatures between 100°C-1800°C, and employing adjustable nozzles for flame development and oxygen/air injection to prevent unburned or overburned spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional vertical shaft kilns are used, then the structure is simple, but sintering efficiency is low due to uncontrolled burning zones
Solution Approach 1:
The kiln is divided into multiple zones (drying zone, calcining zone, sintering zone, cooling zone) with distinct functions. The sintering zone is further segmented into a central region and an annular region, allowing independent control of burning zones to prevent unburned spots and improve sintering efficiency
Solution Approach 2:
Different regions of the kiln are provided with different heating conditions and structural characteristics. The annular sintering zone has a specific gap width (0.5-2.0m) between walls to control heat distribution, while the central region has different characteristics, creating localized optimal conditions for each zone's function
2Device complexity
If conventional vertical shaft kilns are used, then the structure is simple, but production capacity is limited to maximum 300 tons/day
Solution Approach 1:
The kiln transitions from a simple single-channel structure to a multi-dimensional annular structure with inner and outer walls creating multiple flow paths. This dimensional expansion allows significantly increased production capacity (up to 12,000 tons/day) while maintaining the vertical shaft configuration
3Device complexity
If uncontrolled burning zones develop in the center of the sintering zone, then the kiln structure remains simple, but production output includes high amount of unburned material
Solution Approach 1:
The sintering zone is divided into central and annular regions with different heating characteristics. The annular region's gap width is specifically controlled (0.5-2.0m) to ensure proper heat distribution and prevent unburned spots in the central region, improving sintering quality
Solution Approach 2:
The kiln design incorporates natural feedback mechanisms where the heat distribution pattern and material flow rate self-regulate the burning process. The gap width between walls creates a natural heat distribution pattern that prevents overheating in the center while ensuring complete combustion
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 configuration enhances sintering efficiency, allowing for higher production capacities up to 12,000 tons/day, ensuring complete transformation of raw materials into clinker form with uniform heating, reducing unburned or overburned material, and enabling precise control over the sintering process.
Implementation Method 1
heat of the raw material itself by burning a fuel bonded to the raw material or additional external burners arranged through the drying, calsining, sintering, clinkerizing and gasification zone
Implementation Method 2
the length of a gap between the first wall and the second wall throughout the vertical burning zone, namely a drying, calsining, sintering, clinkerizing and gasification zone, particularly the intermediate sintering zone is arranged so that a heat distribution pattern inside the drying, calsining, sintering, clinkerizing and gasification zone is homogeneously transform complete flowing raw material into the clinker form
Implementation Method 3
employing adjustable nozzles for flame development and oxygen/air injection to prevent unburned or overburned spots
Data Source
AI summary
Invention relates to a vertical ring shaft kiln comprising a vertical burning region (1); an intermediate sintering zone (Z3) surrounded by a first wall (10) and an opposite second wall (20) at the burning region (1) to obtain a clinker from a particulate raw material flowing downwards direction.