Cement Clinker CO2 Concentration via Gas Segmentation
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Solution Overview
Problem
The production of cement clinker results in significant carbon dioxide emissions, primarily due to the decomposition of calcium carbonate and fuel combustion, making it challenging to limit CO2 emissions into the atmosphere effectively.
Innovation Solution
A process and installation design that separates fumes from the rotary kiln and preheater, feeds the precalcination reactor with an oxygen-rich gas, and recycles part of the preheater gases to concentrate CO2, allowing for its sequestration, while using recycled heat to reduce fuel consumption and maintain material suspension flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fumes from rotary kiln and preheater are mixed in conventional installations, then heat recovery efficiency is improved, but CO2 concentration is diluted making sequestration difficult
Solution Approach 1:
The invention segments the fume flow into two separate streams: one from the preheater and another from the rotary kiln. The preheater fumes are directed to the precalcination reactor where CO2 is concentrated, while rotary kiln fumes are used for heat recovery purposes. This segmentation allows simultaneous optimization of both heat recovery efficiency and CO2 concentration for sequestration.
Solution Approach 2:
The invention introduces an intermediary mechanism (separate fume routing system) that enables the preheater fumes to be selectively directed to the precalcination reactor without mixing with rotary kiln fumes. This intermediary arrangement preserves the high CO2 concentration in preheater fumes while still allowing heat recovery from both streams through their respective pathways.
2Object-generated harmful factors
If precalcination reactor is fed with oxygen-rich gas, then CO2 concentration is improved for sequestration, but device complexity increases
Solution Approach 1:
The invention makes the oxygen-rich gas supply system serve multiple functions: it provides the necessary oxygen for complete combustion in the precalcination reactor, enables CO2 concentration in the exhaust gases for sequestration, and maintains operational flexibility. This multi-functionality justifies the added complexity by delivering multiple benefits from a single system modification.
Solution Approach 2:
The invention changes the compositional parameter of the combustion air supplied to the precalcination reactor, using oxygen-rich gas with higher O2 content and lower N2 content compared to ambient air. This parameter change directly increases CO2 concentration in the exhaust gases, making sequestration economically viable while the gas supply system handles the modified composition.
3Ease of operation
If part of preheater gases is recycled, then material suspension flow is maintained, but CO2-rich gas flow for sequestration is reduced
Solution Approach 1:
The invention applies partial recycling of preheater gases, directing only a portion (e.g., 10-30%) back to the precalcination reactor inlet to maintain material suspension flow, while the majority of the CO2-rich gases are diverted to sequestration facilities. This partial action optimizes the balance between operational requirements and sequestration goals.
Solution Approach 2:
The invention segments the recycled gas flow from the sequestration gas flow using separate routing pathways. The recycled portion is directed back to the precalcination reactor inlet to maintain suspension, while the sequestration portion is directed to CO2 capture facilities. This segmentation allows independent optimization of both flows without compromising either material suspension or CO2 concentration.
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 effectively concentrates CO2 emissions for sequestration, reducing atmospheric CO2 discharge by approximately 78% and optimizing energy use by recycling heat, thereby minimizing the environmental impact of cement clinker production.
Implementation Method 1
the precalcination reactor is fed with an oxygen-rich gas whose nitrogen content is less than 30%, constituting the only source of oxygen of said reactor
Implementation Method 2
a clinker cooler by blowing a cooling gas, at the outlet of said rotary kiln, generating hot gas
Implementation Method 3
the fumes produced by the rotary kiln and the gases from the preheater are separated so that said fumes and said gases do not mix
Implementation Method 4
part of the gases leaving said cyclone preheater is recycled in said precalcination reactor, or even said preheater, so as to obtain an adequate flow necessary for the suspension of the materials
Data Source
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AI summary
The invention relates to a process for manufacturing cement clinker in a plant comprising a cyclone preheater (3, 3a), a precalcination reactor (4), a rotary furnace and clinker cooler. According to the invention, the flue gases produced by the rotary furnace are separated from the gases from the preheater so as not to mix them, the precalcination reactor is fed with an oxygen-rich gas and a portion (8a) of the gases (8) leaving the cyclone preheater (3, 3a) is recycled into said precalcination reactor (4), or even into the preheater (3, 3a) so as to obtain a flux suitable for suspending matter in the preheater. The non-recycled other portion (8b) of the gases, rich in carbon dioxide, is adapted for the purpose of limiting the amount of CO2 discharged, by means such as sequestration means.