Methanol Reactor Pressure Control via Hydrogen Recovery
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Solution Overview
Problem
Methanol synthesis plants face operational disruptions due to failures in the synthesis gas compressor, leading to pressure losses and incomplete conversion of synthesis gas, which affects the stoichiometry and overall efficiency of methanol production.
Innovation Solution
The method involves adjusting the hydrogen recovery flow to compensate for compressor failures by increasing its pressure and redirecting it through different lines within the plant, ensuring continued operation by maintaining high pressure in the methanol reactor stages, even after a compressor failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the synthesis gas compressor is used to increase pressure for methanol synthesis, then the reaction efficiency and throughput are improved, but the system reliability deteriorates due to single point of failure
Solution Approach 1:
The patent applies local quality by differentiating the pressure increase function between two separate gas flows: fresh synthesis gas and recycled hydrogen-containing gas. The fresh synthesis gas is pressurized by the synthesis gas compressor, while the recycled hydrogen-containing gas is pressurized by a separate recycle gas compressor. This distribution of pressure increase functions to different components allows the system to maintain productivity through alternative pressurization paths when one compressor fails, thereby resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent implements dynamics by enabling flexible switching between different gas supply paths and pressurization mechanisms. The system can dynamically adjust the proportion of fresh synthesis gas and recycled hydrogen-containing gas, and switch between using the synthesis gas compressor or the recycle gas compressor for pressurization. This dynamic adaptability allows the system to maintain operational continuity and productivity even when one compressor fails, resolving the reliability-productivity contradiction.
2Reliability
If the synthesis gas compressor fails, then system reliability is compromised, but complete operational shutdown is avoided through alternative pressurization paths
Solution Approach 1:
The patent applies segmentation by dividing the gas compression function into two independent subsystems: one handling fresh synthesis gas with its dedicated compressor, and another handling recycled hydrogen-containing gas with its own recycle gas compressor. This segmentation creates redundancy, allowing the system to maintain operational continuity if one compressor fails, while the added complexity is justified by the improved reliability and avoidance of complete shutdown.
Solution Approach 2:
The patent implements multi-functionality by designing the recycle gas compressor to serve dual purposes: compressing recycled hydrogen-containing gas for reactor feed, and serving as a backup pressurization source when the synthesis gas compressor fails. This multi-functional design increases device complexity but resolves the contradiction by enabling operational continuity through alternative pressurization paths.
3Productivity
If hydrogen recovery flow is increased to compensate for compressor failure, then productivity is maintained, but pressure control complexity increases
Solution Approach 1:
The patent applies feedback by implementing a control system that monitors the operational status of compressors and automatically adjusts the flow rates of fresh synthesis gas and recycled hydrogen-containing gas. When the synthesis gas compressor fails, the control system increases the hydrogen recovery flow and adjusts the recycle gas compressor operation to maintain the required pressure and productivity. This feedback mechanism maintains productivity while managing pressure control complexity through automated responses rather than manual intervention.
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 allows the methanol synthesis plant to maintain operation and economic viability by ensuring partial conversion of synthesis gas to methanol, despite reduced throughput, by adjusting the hydrogen flow to compensate for pressure losses and optimizing reactor conditions.
Implementation Method 1
a synthesis gas flow comprising hydrogen and carbon oxides is supplied to a synthesis gas compressor of the plant to increase the pressure of the synthesis gas flow
Implementation Method 2
in which the exothermic reaction for the production of methanol takes place
Data Source
AI summary
A method for operating a plant for synthesizing methanol, wherein a synthesis gas flow having hydrogen and carbon oxides is supplied to a synthesis gas compressor of the plant to increase the pressure of the synthesis gas flow. The pressure-increased synthesis gas flow is supplied to a methanol reactor arrangement of the plant for partial conversion to methanol. The plant has a hydrogen recovery arrangement which obtains an H-recycling flow including hydrogen from a recovery flow supplied from the methanol reactor arrangement, which hydrogen is converted at least in part to methanol. Upon failure of the synthesis gas compressor, the synthesis gas flow continues to be supplied to the methanol reactor arrangement for partial conversion to methanol. Following failure of the synthesis gas compressor, a line arrangement of the plant is switched such that the H-recycling flow is adjusted to compensate for a pressure loss in the methanol reactor arrangement.