Negative-Carbon Cement Through CO2 Hydrogenation And Methane Pyrolysis
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Solution Overview
Problem
Cement manufacturing is a significant source of carbon dioxide emissions, primarily from calcination and fuel combustion, with current carbon capture methods being costly and inefficient.
Innovation Solution
A process and system that integrates methane pyrolysis into cement production, converting emitted CO2 into solid carbon by hydrogenation, pyrolyzing methane to produce solid carbon and hydrogen, and using hydrogen to offset energy needs in calcination and pyrolysis, thereby reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If CO2 capture methods (amine scrubbers or calcium-looping) are used, then carbon emissions are reduced, but costs associated with compression, storage and transportation of CO2 gas increase
Solution Approach 1:
The patent converts the harmful CO2 gas emitted during calcination into useful solid carbon through hydrogenation and pyrolysis reactions. The CO2 that would normally be wasted is transformed into valuable carbon products, eliminating the need for expensive compression, storage and transportation infrastructure while achieving carbon reduction.
Solution Approach 2:
The patent changes the physical state of carbon from gaseous CO2 to solid carbon through chemical reactions (hydrogenation followed by pyrolysis). This phase change from gas to solid eliminates the need for complex gas handling infrastructure and enables direct incorporation of carbon into building materials.
2Productivity
If fuel combustion is used to heat raw materials, then cement production is sustained, but CO2 emissions increase
Solution Approach 1:
The patent creates a self-sustaining system where the hydrogen produced during methane pyrolysis is used to provide heat for both the pyrolysis process and the calcination process. This internal heat generation eliminates the need for external fuel combustion, allowing cement production to continue without additional CO2 emissions from heating.
Solution Approach 2:
The patent merges the heating function with the carbon conversion function by using the hydrogen produced in the pyrolysis step to fuel the calcination process. This integration eliminates separate fuel combustion operations and reduces overall CO2 emissions while maintaining productivity.
3Object-generated harmful factors
If methane pyrolysis is integrated into cement production, then CO2 is converted into solid carbon, but energy requirements for pyrolysis and calcination must be met
Solution Approach 1:
The system is designed to be self-sufficient in energy production, where the hydrogen generated during methane pyrolysis is burned to produce heat that fuels both the pyrolysis and calcination processes. This eliminates the need for external energy inputs and offsets the energy requirements internally.
Solution Approach 2:
The patent establishes a continuous cycle where methane is pyrolyzed to produce hydrogen, which is then used to heat the calcination and pyrolysis processes. This continuous utilization of the produced hydrogen ensures sustained operation without energy interruptions or external fuel dependencies.
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
Achieves a net negative carbon emission on a gigatonne-per-year scale by converting CO2 into solid carbon, eliminating external fuel combustion emissions and improving energy efficiency with hydrogen-powered reactions.
Implementation Method 1
calcining a substance comprising calcium carbonate in a first reaction at a calcination temperature to produce calcium oxide and carbon dioxide
Implementation Method 2
reacting the carbon dioxide from the calcination reaction with reactant hydrogen gas in a second reaction at a hydrogenation temperature to produce methane and water
Implementation Method 3
pyrolyzing the methane from the hydrogenation reaction in a third reaction at a pyrolysis temperature to produce solid carbon and product hydrogen gas
Implementation Method 4
reacting at least a portion of the product hydrogen gas with oxygen to produce water and heat
Data Source
AI summary
The present disclosure relates to negative-carbon cement (NC2) production, which can be achieved by integrating carbon dioxide hydrogenation and methane pyrolysis into the cement manufacturing process, using hydrogen gas derived from methane pyrolysis as the fuel for heating, and converting any captured carbon dioxide into solid carbon. The solid carbon can be incorporated into building materials such as portland cement and gypsum boards, fixing the carbon to achieve cradle-to-gate emission reduction.