Oxygen-Enriched Cement Clinker Combustion Control
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Solution Overview
Problem
The existing cement production processes result in cement with a low proportion of alite (tricalcium silicate), leading to poor early strength and high energy expenditure in grinding, due to high belite (dicalcium silicate) content and inefficient combustion practices.
Innovation Solution
A process that controls the oxygen supply to the furnace based on temperature measurements, using an oxygen-rich combustion gas to increase the lime standard and alite content in cement clinker, achieved through open-loop/closed-loop control systems, ensuring stoichiometric or superstoichiometric combustion conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional combustion gas is used in the furnace, then the process is simple, but the alite content in cement clinker is low and early strength is poor
Solution Approach 1:
The patent applies oxygen-enriched combustion gas (oxygen content >20.5%, preferably >30%, especially >95% or 100%) to accelerate combustion in the furnace. This strong oxidant approach increases the lime standard and alite content in cement clinker, thereby improving early cement strength. The oxygen-rich environment promotes more complete and intense combustion reactions, transforming the chemical composition toward higher alite content.
Solution Approach 2:
The patent implements closed-loop control of oxygen supply based on temperature measurements within the furnace. A temperature measurement device monitors the furnace interior temperature, and a control device adjusts the oxygen supply rate accordingly to maintain optimal combustion conditions. This feedback mechanism ensures stable alite formation while managing system complexity through automated control.
2Use of energy by moving object
If high belite content is produced, then the raw meal composition is easier to achieve, but energy expenditure in grinding is high
Solution Approach 1:
By introducing oxygen-enriched combustion gas, the patent accelerates combustion and increases furnace temperature, promoting the formation of alite (tricalcium silicate) over belite (dicalcium silicate). Alite-rich clinker requires less grinding energy, directly addressing the energy consumption issue. The high oxygen content enables more efficient conversion of raw meal components into alite mineral phase.
Solution Approach 2:
The patent changes the combustion parameters by increasing oxygen concentration in the combustion gas and controlling the oxygen supply rate based on furnace temperature. These parameter changes shift the chemical reactions toward alite formation, optimizing the clinker mineralogy to reduce grinding energy requirements while maintaining precise control over mineral composition.
3Quantity of substance
If oxygen supply to the furnace is increased, then the lime standard and alite content improve, but the combustion control becomes more complex
Solution Approach 1:
The patent uses closed-loop control where a temperature measurement device continuously monitors furnace temperature and a control device adjusts the oxygen supply rate accordingly. This feedback system automates the complex task of oxygen management, making operation easier while maintaining optimal alite content. The system self-regulates to prevent overheating or incomplete combustion.
Solution Approach 2:
The patent replaces manual or simple mechanical oxygen control with an automated control system that uses temperature measurements to regulate oxygen supply. This substitution of mechanical control with an instrumented control system reduces operational complexity while achieving precise control over alite content through automated adjustment of oxygen flow based on real-time temperature data.
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 process enhances the alite content in cement clinker, improving strength properties and reducing energy consumption in grinding, while allowing for precise control of the lime standard and furnace temperature.
Implementation Method 1
burning the preheated and calcined raw meal in a furnace to give cement clinker, wherein the furnace is supplied with a combustion gas having an oxygen content... stoichiometric or superstoichiometric combustion conditions
Implementation Method 2
preheating raw meal in a preheater
Implementation Method 3
calcining the preheated raw meal in a calciner
Implementation Method 4
cooling the cement clinker in a cooler
Data Source
AI summary
A process for producing cement clinker, may involve preheating raw meal in a preheater, calcining the preheated raw meal in a calciner, and burning the preheated and calcined raw meal in a furnace to give cement clinker. The furnace may be supplied with a combustion gas having an oxygen content, and the temperature within the furnace is ascertained. The process may involve cooling the cement clinker in a cooler. The oxygen supply to the furnace is under closed-loop control as a function of the temperature ascertained within the furnace. The temperature ascertained is compared with a target value and, in the event of any variance of the temperature ascertained from the target value, the oxygen supply to the furnace and/or to the calciner is increased or decreased. The target value is adjusted depending on a particle size distribution and/or a lime standard.