Direct-fired sCO2 Cycle Hydrogen Production via Water Gas Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing direct-fired supercritical CO2 power cycles face challenges with contamination from post-combustion products like water and carbon monoxide, which affect power cycle performance and require additional components for separation and venting, leading to inefficiencies and environmental concerns.
Innovation Solution
A direct-fired supercritical CO2 power generation system that includes a combustor for burning hydrocarbon fuel and oxygen, with the output from the combustor being processed in a water gas shift reactor to convert carbon monoxide and water into carbon dioxide and hydrogen, followed by hydrogen separation using a pressure swing adsorption device or cryogenic separator, eliminating the need for a liquid water separator and reducing CO2 venting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a liquid water separator vessel is used to remove water from the supercritical CO2 flow, then water contamination is reduced, but the device complexity increases and separation efficiency is limited due to near-unity density ratio
Solution Approach 1:
The harmful water component is extracted from the supercritical CO2 flow through a membrane separation process. The membrane selectively allows water to pass through while retaining CO2, effectively removing water contamination without requiring a complex liquid separator vessel.
Solution Approach 2:
The mechanical liquid water separator vessel is replaced with a membrane-based separation system. This substitution eliminates the need for complex mechanical separation equipment while achieving more effective water removal through selective membrane permeation.
2Reliability
If CO2 is vented to limit CO concentration, then power cycle performance is maintained, but CO2 loss increases and additional CO2 compression is required
Solution Approach 1:
A feedback control system monitors CO concentration in the supercritical CO2 flow and dynamically adjusts the hydrogen injection rate. When CO concentration approaches problematic levels, the system automatically increases hydrogen injection to enhance CO conversion, preventing the need for CO2 venting while maintaining power cycle performance.
Solution Approach 2:
The system uses the waste heat from the combustion process to drive the water-gas shift reaction that converts CO to CO2. This self-service approach utilizes the process's own thermal energy to eliminate harmful CO without requiring external energy input or CO2 venting.
3Use of energy by moving object
If heat exchangers are used to transfer heat to sCO2, then heat transfer efficiency is improved, but material temperature limits and cost increase
Solution Approach 1:
The combustion chamber and heat transfer process are merged into a single direct-fired system. Fuel combustion occurs directly within the supercritical CO2 flow, eliminating the need for separate heat exchanger components and allowing heat transfer without material temperature limits.
Solution Approach 2:
The supercritical CO2 itself serves as the intermediary medium that directly absorbs combustion heat. Rather than using a heat exchanger wall as an intermediary, the CO2 flow directly contacts the combustion zone, enabling efficient heat transfer while avoiding material temperature constraints.
4Quantity of substance
If hydrogen is produced through water-gas shift reaction, then hydrogen availability increases for utilization, but CO2 concentration changes require monitoring and adjustment
Solution Approach 1:
The system incorporates feedback control that monitors CO2 composition and automatically adjusts hydrogen injection rates. This ensures optimal hydrogen production through the water-gas shift reaction while maintaining appropriate CO2 concentration levels for power cycle operation, eliminating the need for manual monitoring and adjustment.
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 solution effectively removes hydrogen and excess CO2, enhancing power cycle efficiency, reducing contamination, and enabling the utilization or storage of hydrogen, while potentially increasing hydrogen production to over 1000-1250 kg per day.
Implementation Method 1
a water gas shift reactor for reacting the carbon monoxide and water output from the combustor and forming a water gas shift reactor output mixture of carbon dioxide and hydrogen
Implementation Method 2
A pressure swing adsorption device or a cryogenic separator is provided that is configured to remove all or a portion of the hydrogen output from the water gas shift reactor
Implementation Method 3
A pressure swing adsorption device or a cryogenic separator is provided that is configured to remove all or a portion of the hydrogen output from the water gas shift reactor
Data Source
AI summary
Direct-fired supercritical carbon dioxide (CO2) power cycle that generates hydrogen. More specifically, the discharge of a direct fired supercritical CO2 power cycle is converted to carbon dioxide and hydrogen where the hydrogen and/or carbon dioxide can be separated and stored/utilized in another application.