Oxy-calcination Process for Cement Clinker Production
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Solution Overview
Problem
The cement industry faces challenges in reducing CO2 emissions during the calcination process due to increased CO2 partial pressure in oxycombustion, leading to higher calciner temperatures and increased risk of hotspots and material build-ups, which affect process efficiency and require costly shutdowns.
Innovation Solution
A method for calcining cement raw meal using oxy-combustion with a calciner oxidant of 30-100% oxygen content, introducing fuel and oxidant in a way that creates an oxygen-lean or fuel-lean zone to ensure complete combustion and minimize excess oxygen, thereby reducing the formation of detrimental build-ups and maintaining process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxycombustion is used to reduce CO2 emissions, then CO2 capture efficiency is improved, but calciner temperature increases leading to hotspots and material build-ups
Solution Approach 1:
The patent applies local quality by creating distinct zones within the calciner with different oxygen concentrations. An oxygen-lean zone is established at the lower part where raw meal is introduced, while an oxygen-rich zone is maintained at the upper part where fuel combustion occurs. This spatial differentiation of oxygen distribution prevents excessive temperature rise and material build-ups in the lower zone while maintaining efficient combustion and CO2 capture in the upper zone.
2Productivity
If calciner temperature is increased to counteract high CO2 partial pressure, then decarbonation reaction efficiency is improved, but risk of hotspots and material build-ups increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the oxygen concentration distribution and temperature profile within the calciner. By introducing oxidant at different locations and controlling the oxygen content in different zones, the system maintains optimal temperature for decarbonation (around 900-1000°C) in the upper zone while preventing excessive temperature rise in the lower zone, thus avoiding hotspots and material build-ups.
3Reliability
If conventional air-combustion is used, then operating stability is maintained, but CO2 emissions are high requiring expensive capture technology
Solution Approach 1:
The patent applies strong oxidants by using oxygen-enriched air (oxidant containing 21-100% oxygen) instead of conventional air for fuel combustion in the calciner. This accelerated oxidation process significantly increases the CO2 concentration in the flue gas (achieving 40-90% CO2), thereby reducing CO2 emissions and eliminating the need for expensive post-combustion capture technology like amine scrubbing, while maintaining operating stability through controlled oxygen distribution.
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 approach allows for sufficient calcination while preventing material build-ups in the calciner, reducing the risk of hotspots, and achieving efficient CO2 capture without the need for expensive amine scrubbing technology, enabling the production of cement clinker with reduced CO2 emissions.
Implementation Method 1
Fuel and calciner oxidant are introduced into the calciner. The fuel is burnt with the calciner oxidant to generate heat inside the calciner.
Implementation Method 2
significant amounts of CO2 are more particularly generated during the decarbonation of raw meal (CaCO3) to lime (CaO) via the following reversible equilibrium reaction
Data Source
AI summary
Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.