Cement Waste Heat Recovery for Self-Powered Carbon Capture
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Solution Overview
Problem
Conventional carbon capture and storage (CCS) processes in cement plants are energy-intensive and emit additional CO2 due to reliance on fossil fuel-based heating, with waste heat recovery configurations being inefficient and dependent on variable industrial operations, leading to increased carbon emissions and energy consumption.
Innovation Solution
A waste heat recovery system integrated with cement production processes, utilizing preheater and clinker cooler exhausts to generate both electrical and thermal energy for carbon capture, reducing the need for fossil fuel-based heating by incorporating supplementary firing and steam turbines to produce all required energy on-site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional CCS plants use fossil fuel-based heating for sorbent regeneration, then the required thermal energy is supplied, but additional CO2 emissions are generated increasing the net carbon captured amount
Solution Approach 1:
The patent converts the harmful waste heat from cement kilns (which would otherwise be discarded) into useful thermal energy for sorbent regeneration. The waste heat from preheater and clinker cooler exhausts is captured and directed to the desorption unit, transforming a harmful emission source into a beneficial energy source that eliminates the need for fossil fuel-based heating.
Solution Approach 2:
The patent merges the waste heat recovery system with the CCS process by integrating the preheater and clinker cooler exhaust streams directly into the sorbent regeneration system. This combination allows the CCS plant to utilize existing thermal energy from the cement process rather than requiring separate fossil fuel heating.
2Loss of energy
If waste heat recovery units are positioned upstream of CCS process, then waste heat from independent operations is recovered, but the available waste heat energy is entirely dependent on independent operation schedules and may be insufficient
Solution Approach 1:
The patent combines the waste heat recovery system with the CCS process itself, positioning the heat recovery units (preheater and clinker cooler) as integral parts of the cement kiln system rather than separate independent operations. This integration ensures that waste heat is continuously available based on the cement production schedule, eliminating dependence on external independent operations.
Solution Approach 2:
The cement kiln system serves itself by utilizing its own waste heat (from preheater and clinker cooler exhausts) to provide thermal energy for the CCS process. This self-sufficiency eliminates the need to rely on external waste heat sources and ensures consistent energy availability aligned with the cement production schedule.
3Power
If conventional WHR units release excess waste heat to atmosphere through condensers, then waste heat energy is recovered to generate electricity, but the released heat reduces overall energy efficiency
Solution Approach 1:
Instead of discarding excess waste heat to the atmosphere through condensers, the patent converts this wasted thermal energy into a useful resource by directing it to the sorbent regeneration process. The heat that would have been lost is now utilized for CO2 separation, transforming an energy loss into a beneficial process input.
Solution Approach 2:
The waste heat recovery system serves multiple functions: it generates electricity through steam turbines while simultaneously providing thermal energy for sorbent regeneration. This multi-functionality ensures that no waste heat is wasted, maximizing energy utilization efficiency.
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 system achieves self-sufficient energy generation for carbon capture, minimizing additional carbon emissions and energy consumption, while effectively capturing CO2 from cement processes.
Implementation Method 1
a steam turbine configured to receive at least the second steam flow, the steam turbine configured to output a third steam flow, the steam turbine configured to produce at least 100% of the electrical energy requirements of the carbon capture process by spinning a generator
Implementation Method 2
a first waste heat recovery unit configured to receive a first fluid flow, the first waste heat recovery unit configured to receive the first recovery flow and heat the first fluid flow, the second waste heat recovery unit configured to receive a second fluid flow, the second waste heat recovery unit configured to receive the second recovery flow and heat the second fluid flow
Implementation Method 3
a carbon capture process configured to extract CO2 from at least the first recovery flow
Data Source
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AI summary
A waste heat recovery system for use with a cement production process with a carbon capture process includes a cement process preheater configured to receive flue gas from a kiln and supply preheater exhaust to a first waste heat recovery unit, a clinker cooler configured to discharge heated air to a second waste heat recovery unit, the second waste heat recovery unit including a burner, the second waste heat recovery unit configured to supply a high pressure steam flow to a steam turbine, the steam turbine configured to produce all of the electrical energy required a carbon capture process and output a third steam flow, the third steam flow supplies at least 80% of the heat energy required by the carbon capture process, the carbon capture process captures carbon dioxide from the exhaust gas of at least the first waste heat recovery unit via a sorbent media.