Cryogenic CO Distillation Buffering for Stable Production Flow
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Solution Overview
Problem
Existing methods for producing carbon monoxide through cryogenic distillation face fluctuations in production rate due to carbon monoxide adsorption by molecular sieves, leading to instability in downstream units and cold balance disequilibrium.
Innovation Solution
A buffer vessel located at the bottom of the scrubber in the cold box accumulates liquefied synthesis gas outside elution phases, stabilizing carbon monoxide production by adjusting liquid levels and flow rates during elution phases, maintaining cryogenic liquid inventories and cold balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molecular sieve is used to adsorb moisture and carbon dioxide, then purification is improved, but carbon monoxide production rate fluctuates due to CO adsorption
Solution Approach 1:
An elution phase is introduced before the adsorption phase during which the molecular sieve is pre-saturated with carbon monoxide. This preliminary action ensures that when the adsorption phase begins, the sieve is already saturated with CO and does not adsorb additional CO, thereby eliminating production rate fluctuations while maintaining purification effectiveness.
2Productivity
If elution phase is introduced to saturate adsorbent with carbon monoxide, then production stability is improved, but cold balance disequilibrium occurs
Solution Approach 1:
The invention utilizes phase transitions of synthesis gas and methane between liquid and vapor states to manage the cold balance. During the elution phase, when CO production decreases, liquid synthesis gas accumulates in the buffer vessel. The associated phase change and heat transfer effects help compensate for the cold balance disruption caused by the elution operation, thereby maintaining overall thermal equilibrium in the cryogenic system.
3Productivity
If liquid carbon monoxide vessel is used as buffer volume, then carbon monoxide production stability is improved, but implementation difficulty increases due to cold balance disequilibrium
Solution Approach 1:
A buffer vessel serving as an intermediary component is introduced between the adsorption unit and the cryogenic separation unit. This buffer vessel accumulates liquid synthesis gas during normal operation and releases it during elution phases, acting as a mediator that decouples the unstable CO production from the downstream units. This intermediary approach simplifies implementation compared to using a dedicated liquid CO vessel while achieving the same stabilizing effect.
4Productivity
If synthesis gas is accumulated in buffer vessel during non-elution phases, then carbon monoxide production stability is improved, but liquid methane retention in separator must be adjusted
Solution Approach 1:
The invention implements dynamic operational adjustments where the retention of liquid methane in the separator and the level of the stripper are progressively modified based on the operational phase. During non-elution phases when synthesis gas accumulates in the buffer, liquid methane retention is reduced. During elution phases when synthesis gas is depleted, liquid methane retention is increased. This dynamic adaptation allows the system to maintain stability while accommodating the buffer vessel operations.
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 approach ensures a constant carbon monoxide flow rate and stable operating conditions by regulating the carbon monoxide turbine and adjusting liquid levels in separators, maintaining cryogenic liquid inventories and cold balance equilibrium.
Implementation Method 1
the molecular sieve has the property of adsorbing significant amounts of carbon monoxide
Implementation Method 2
method for producing carbon monoxide and/or hydrogen by cryogenic distillation
Implementation Method 3
the purified gas mixture is partially liquefied to produce liquefied gas mixture
Data Source
AI summary
The invention relates to a method for producing carbon monoxide consisting, during an adsorption step, in using N adsorbers (4A, 4B), wherein N is equal to greater than two, each of which follows, at an offset; the same period T cycle during which adsorption and regeneration phases succeed each other, in exposing, at the beginning of the adsorption phase, each adsorber to an eluting phase during which only a part of a nominal flowrate of the mixture is transferred to the adsorber until said adsorber is substantially carbon monoxide saturated while at least the second adsorber is maintained in the adsorption phase and a purified gaseous mixture is partially liquefied for producing a liquefied gaseous mixture, in storing said mixture in a capacity (7) and in transferring the liquefied gaseous mixture from the capacity to at least one column (11) for the separation thereof into a carbon monoxide rich product and, during at least one part of the adsorber eluting phases, the liquid level in the container is decreased and during at lest one part of the cycle outside of the eluting periods, said level is increased.