Calcium Oxide Sorbent Hydration for CO2 Capture
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Solution Overview
Problem
Existing methods for capturing CO2 from process gases using metal oxides face inefficiencies due to sintering and sulfur interference, which reduces the regeneration capacity of sorbents.
Innovation Solution
A system comprising three reactors: a carbonator for capturing CO2 to form calcium carbonate, a calciner for decarbonation to regenerate calcium oxide, and a hydrator for hydrating calcium oxide to calcium hydroxide, enhancing sorbent regeneration and surface area by swelling the sorbent material, thus overcoming sintering and sulfur-related efficiency losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal oxide sorbent is used for CO2 capture at high temperatures, then CO2 capture capacity is improved, but sintering occurs reducing sorbent efficiency
Solution Approach 1:
The patent introduces a hydration step that changes the chemical state of calcium oxide to calcium hydroxide, which prevents sintering while maintaining CO2 capture capacity. This parameter change in the sorbent material's chemical composition resolves the contradiction between high-temperature capture efficiency and sorbent stability.
Solution Approach 2:
The system uses a composite approach by cycling between calcium oxide, calcium carbonate, and calcium hydroxide forms. This composite material strategy maintains porosity and prevents sintering while enabling efficient CO2 capture and regeneration.
2Productivity
If sulfur is present in the process gas, then sulfur carbonate forms reducing sorbent efficiency, but complete sulfur removal is difficult
Solution Approach 1:
The patent converts the harmful effect of sulfur by using the hydration step to form calcium hydroxide, which has different reactivity characteristics. The hydrated sorbent is less prone to forming stable sulfur carbonates, thereby converting the harmful sulfur interaction into a manageable process condition.
Solution Approach 2:
By changing the chemical form of the sorbent through hydration, the patent alters the sorbent's reactivity toward sulfur compounds. This parameter change reduces the formation of sulfur carbonate and maintains CO2 capture efficiency even in the presence of sulfur.
3Loss of energy
If sorbent is regenerated by simple heating, then energy consumption is reduced, but regeneration efficiency is insufficient
Solution Approach 1:
The patent utilizes phase transitions and chemical transformations in the sorbent material. The hydration step transforms calcium oxide to calcium hydroxide, which then decomposes upon heating to regenerate calcium oxide. This phase transition approach improves regeneration efficiency while managing energy consumption through controlled chemical reactions.
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 efficiently captures CO2 from process gases, including those with sulfur, by effectively regenerating the sorbent material through hydration, improving its capture efficiency and reducing blockages, thereby enhancing overall CO2 capture performance.
Implementation Method 1
a first reactor arranged to receive a stream of process gas and a particulate sorbent material comprising calcium oxide able to capture the CO 2 present in the process gas such that calcium carbonate is formed
Implementation Method 2
the second reactor comprising heating means arranged to cause release of CO 2 from the particulate sorbent material by decarbonation of the calcium carbonate to form calcium oxide
Implementation Method 3
the third reactor comprising means for supplying H 2 O to the second portion of particulate sorbent material to hydrate at least a part of a remaining portion of calcium oxide of the second portion of particulate sorbent material to form calcium hydroxide
Data Source
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AI summary
The present disclosure is directed to a system for capturing CO2 from a process gas. The system comprises a first reactor arranged to receive a stream of process gas and a particulate sorbent material comprising calcium oxide able to capture the CO2 present in the process gas such that calcium carbonate is formed, the first reactor comprising means for discharging CO2 depleted process gas, a first portion of particulate sorbent material having captured CO2, and a second portion of particulate sorbent material having captured CO2, a second reactor arranged to receive the first portion of particulate sorbent material from the first reactor, the second reactor comprising heating means arranged to cause release of CO2 from the particulate sorbent material by decarbonation of the calcium carbonate to form calcium oxide, the second reactor further comprising means for returning the first portion of particulate sorbent material to the first reactor and means for discharging a CO2 rich gas stream, and a third reactor arranged to receive the second portion of particulate sorbent material from the first reactor, the third reactor comprising means for supplying water to the second portion of particulate sorbent material to hydrate at least a part of a remaining portion of calcium oxide of the second portion of particulate sorbent material to form calcium hydroxide, the third reactor further comprising means for returning the second portion of particulate sorbent material to the first reactor.