Cement Calciner Oxygen Combustion CO2 Capture
Solution Overview
Problem
The cement production process generates substantial carbon dioxide emissions, primarily due to the calcination of calcium carbonate and combustion of carbon-containing fuels, which is environmentally undesirable and costly to mitigate through existing separation methods.
Innovation Solution
A process involving the calcination of cement raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas comprising oxygen and up to 80% carbon dioxide, with the goal of isolating and storing the carbon dioxide-rich gas stream to prevent atmospheric release, using a calciner with multiple inlet points to regulate temperature and ensure complete combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air is used as the combustion gas in the calciner, then nitrogen acts as a diluent reducing combustion temperature and protecting plant equipment, but the carbon dioxide produced is heavily diluted and difficult to separate economically
Solution Approach 1:
The combustion process is segmented into two separate systems: a first combustion system using air to generate heat, and a second combustion system using pure oxygen to produce concentrated carbon dioxide. This segmentation allows each system to optimize for its specific function - temperature control in the first system and gas concentration in the second system - resolving the contradiction between diluted CO2 and temperature control.
Solution Approach 2:
Pure oxygen serves as an intermediary substance introduced into the calciner to replace nitrogen as the combustion gas. This intermediary enables the production of undiluted carbon dioxide by eliminating nitrogen from the combustion atmosphere, while still maintaining the necessary combustion reactions for calcium carbonate decomposition.
2Loss of substance
If pure oxygen is used instead of air for all fuel combustion, then carbon dioxide is not diluted by nitrogen, but the cost increases and combustion proceeds with great vigour generating very high temperatures that can damage plant
Solution Approach 1:
The combustion process is divided into two separate combustion systems: a first combustion system using air that operates at controlled temperatures for general heating, and a second combustion system using pure oxygen that produces concentrated carbon dioxide. This segmentation allows the oxygen-fueled system to operate at lower, safer temperatures while still achieving high CO2 concentration, avoiding plant damage.
Solution Approach 2:
Instead of using pure oxygen for all fuel combustion, the invention applies partial action by using oxygen only for a portion of the combustion process - specifically for generating the carbon dioxide-rich gas stream. The remaining combustion uses air, thereby achieving CO2 concentration benefits without the excessive temperatures and costs associated with complete oxygen substitution.
3Object-generated harmful factors
If the gas stream from the calciner is separated to capture carbon dioxide, then emissions are reduced, but the energy required for separation is too high to make it worthwhile
Solution Approach 1:
The invention applies preliminary action by pre-concentrating carbon dioxide in the calciner before the gas leaves the system. By using pure oxygen as the combustion gas, the CO2 is generated in an undiluted or highly concentrated state from the outset, eliminating the need for energy-intensive separation processes that would otherwise be required to concentrate CO2 from air-combustion flue gases.
Solution Approach 2:
The invention converts the harmful effect of undiluted oxygen combustion (which would normally produce excessively high temperatures) into a benefit by controlling the combustion process to generate concentrated CO2 at manageable temperatures. The potential harm of high-temperature oxygen combustion is transformed into the beneficial outcome of high CO2 concentration suitable for capture and storage.
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 significantly reduces carbon dioxide emissions by producing a gas stream with enhanced carbon dioxide content, suitable for storage, and maintains process efficiency while minimizing excess oxygen and nitrogen usage, thus offering an environmentally beneficial solution for cement production.
Implementation Method 1
heated by combustion of a carbon-containing fuel with a gas comprising oxygen and from 0 to 80% by volume of carbon dioxide
Implementation Method 2
calcination of calcium carbonate to calcium oxide takes place and carbon dioxide is released
Implementation Method 3
combustion of a carbon-containing fuel with a gas comprising oxygen and from 0 to 80% by volume of carbon dioxide
Implementation Method 4
isolating the gas produced by combustion and calcination in the calciner in order not to release the same into the atmosphere
Data Source
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AI summary
The invention provides a process for the production of cement which comprises the calcination of calcium carbonate-containing raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas comprising oxygen and from 0 to 80% by volume of carbon dioxide, and substantially free of nitrogen, and isolating the gas produced by combustion and calcination in the calciner.