Process and apparatus for producing hydrogen and carbon monoxide
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Solution Overview
Problem
Current processes for separating hydrogen and carbon monoxide from crude synthesis gas are not robust and stable, and they lack high energy efficiency, requiring steady feed conditions and inefficient cryogenic separation methods.
Innovation Solution
A process and apparatus that includes a synthesis gas production unit, water and CO2 removal units, pressure swing adsorption, and cryogenic separation, with additional steps to attenuate molar concentration variations and recycle streams to improve hydrogen and carbon monoxide recovery, using a controller to manage pressure and mixing devices to stabilize gas compositions before cryogenic separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cryogenic separation is used to separate carbon monoxide from crude synthesis gas, then carbon monoxide separation is achieved, but the process requires steady feed conditions and is not robust to composition and pressure variations
Solution Approach 1:
A buffer vessel is introduced as an intermediary between the PSA unit and cryogenic separator. This buffer vessel receives the hydrogen product stream from PSA and provides a steady feed to the cryogenic separator, isolating the cryogenic unit from composition and pressure variations in the PSA output.
Solution Approach 2:
The buffer vessel performs preliminary stabilization of the gas stream before it enters the cryogenic separator. By pre-establishing steady flow conditions, the buffer vessel ensures that the cryogenic separation process operates under consistent conditions regardless of upstream variations.
2Reliability
If pressure swing adsorption is used to separate hydrogen from crude synthesis gas, then hydrogen separation is achieved, but the output varies in composition and pressure
Solution Approach 1:
The buffer vessel acts as an intermediary that decouples the PSA unit from downstream requirements. It absorbs composition and pressure variations from the PSA output, providing a stabilized stream to the cryogenic separator while allowing the PSA unit to operate with its inherent cyclic variations.
3Reliability
If conventional separation processes are used, then hydrogen and carbon monoxide can be separated, but energy efficiency is low
Solution Approach 1:
The process utilizes parameter changes in the buffer vessel, specifically pressure and temperature variations, to enhance separation efficiency. By optimizing these parameters, the system achieves better energy efficiency while maintaining reliable separation of hydrogen and carbon monoxide.
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
The solution enhances the robustness and stability of hydrogen and carbon monoxide separation, achieving high recovery rates and energy efficiency by stabilizing gas compositions and recycling streams, thereby improving the overall efficiency of the separation process.
Implementation Method 1
a pressure swing adsorber for separating H2 from the process gas thereby forming the H2-containing product stream and a residual gas stream
Implementation Method 2
a cryogenic separation unit for receiving the residual gas stream after the compressor and after the mixing device, the cryogenic separation unit for separating the residual gas stream into the CO-containing product stream, a H2-enriched stream, a methane-enriched stream, and a CO-containing intermediate stream by cryogenic fractionation
Data Source
Figure 1
AI summary
Apparatus and process for producing a hydrogen-containing product stream and a carbon monoxide-containing product stream from a crude synthesis gas produced in a syngas production unit. Carbon dioxide is removed from the process gas by a non-cryogenic means and the hydrogen-containing product stream is separated from the process gas in a pressure swing adsorber. Residual gas from the pressure swing adsorber is passed to a cryogenic separation unit where the cryogenic separation unit separates the residual gas stream into the carbon monoxide-containing product stream, a hydrogen-enriched stream, a methane-enriched stream, and a carbon monoxide - containing intermediate stream by cryogenic fractionation. At least a portion of the hydrogen-enriched stream is recycled to the pressure swing adsorber.