Hydrogen Production PSA Cryogenic Carbon Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hydrogen production methods incur high investment and operating costs due to the energy-intensive process of amine scrubbing for carbon capture, which also results in significant scrubbing agent losses.
Innovation Solution
A process involving a first pressure swing adsorber (PSA) to fractionate synthesis gas into a carbon dioxide-depleted high-pressure fraction and a carbon dioxide-enriched low-pressure fraction, followed by cryogenic gas fractionation to obtain a high-purity carbon dioxide fraction, thereby achieving high carbon capture rates at lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amine scrubbing is used to separate carbon dioxide from synthesis gas, then carbon capture rate is improved, but investment costs and energy consumption increase significantly
Solution Approach 1:
The carbon dioxide separation process is divided into two distinct stages: first, pressure swing adsorption (PSA) removes the majority of carbon dioxide from synthesis gas to produce a depleted stream; second, cryogenic fractionation further purifies and concentrates carbon dioxide from the PSA low-pressure fraction. This segmentation allows each process to operate in its optimal efficiency range, achieving over 90% carbon capture while avoiding the excessive energy consumption of single-stage amine scrubbing.
Solution Approach 2:
The invention changes the operating parameters of carbon dioxide separation by transitioning from chemical absorption (amine scrubbing) to physical adsorption (PSA) followed by cryogenic separation. The PSA process operates at varying pressures to adsorb and desorb carbon dioxide, while the cryogenic unit operates at low temperatures to fractionate gases based on their different condensation points. These parameter changes fundamentally alter the energy profile of the separation process.
2Reliability
If amine scrubbing is used for carbon dioxide separation, then carbon capture efficiency is improved, but operating costs increase due to scrubbing agent losses
Solution Approach 1:
The invention replaces the chemical system of amine scrubbing with a physical separation system combining pressure swing adsorption and cryogenic fractionation. PSA uses pressure-driven adsorption on solid media to capture carbon dioxide, and cryogenic fractionation uses temperature-driven phase separation. This substitution eliminates the need for liquid amine scrubbing agents entirely, preventing all associated agent losses and the operational costs of replenishing and treating lost chemicals.
3Manufacturing precision
If amine scrubbing is employed to obtain high-purity carbon dioxide, then product purity is improved, but investment costs increase
Solution Approach 1:
The carbon dioxide purification process is segmented into two specialized units: PSA for bulk removal and cryogenic fractionation for final purification. This segmentation allows each unit to be optimized for its specific function, achieving high carbon dioxide purity (suitable for product delivery or sequestration) while distributing capital investment across two smaller, more efficient processes rather than one large, complex amine scrubbing system.
4Reliability
If flue gas is subjected to amine scrubbing, then carbon capture rate is improved, but scrubbing agent losses increase
Solution Approach 1:
The invention replaces chemical amine absorption with physical pressure swing adsorption and cryogenic separation. This mechanical/physical substitution eliminates all scrubbing agent losses that occur during flue gas treatment, while maintaining high carbon capture rates through the combined action of PSA and cryogenic fractionation units.
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 process achieves carbon capture rates of over 90% while reducing costs by leveraging PSA technology and cryogenic fractionation, thereby minimizing energy consumption and scrubbing agent losses.
Implementation Method 1
the synthesis gas consisting largely of hydrogen and carbon dioxide, by means of a first pressure swing adsorber (PSA), is fractionated into a carbon dioxide-depleted first PSA high-pressure fraction and a carbon dioxide-enriched, water-containing first PSA low-pressure fraction
Implementation Method 2
from which the carbon dioxide fraction is obtained by cryogenic gas fractionation
Implementation Method 3
The compressed and dried first PSA low-pressure fraction is cooled and partially condensed, wherein most of the impurities present—in particular hydrogen—are separated in a high-pressure separator
Data Source
AI summary
A process for producing a hydrogen product where a carbon-containing input, by reforming and water gas shift, is converted into a synthesis gas largely consisting of hydrogen and carbon dioxide, from which a hydrogen fraction and a carbon dioxide fraction are separated, wherein the hydrogen fraction has the composition required for the hydrogen product and the carbon dioxide fraction has a purity which allows delivery thereof as a product or disposal thereof through sequestration. The characterizing feature here is that the synthesis gas consisting largely of hydrogen and carbon dioxide, by means of a first pressure swing adsorber, is fractionated into a carbon dioxide-depleted first PSA high-pressure fraction and a carbon dioxide-enriched first PSA low-pressure fraction, from which, after compression, the carbon dioxide fraction is obtained by cryogenic gas fractionation.