Methanol Pre-Reactor Stage Reducing Compressor Power
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Solution Overview
Problem
Current methanol production processes require high energy consumption and investment costs due to the need for gas compressors to compress synthesis gas to high pressures, with limited energy savings from pre-reactor stages and high compressor power consumption.
Innovation Solution
A process that introduces feed gas with a higher carbon monoxide content into a pre-reactor stage, allowing for significant energy savings by reducing the amount of residual gas that needs to be compressed, using a feed gas with a carbon monoxide content of 25% to 36% by volume, and optimizing hydrogen and carbon dioxide contents for enhanced methanol conversion and reduced compressor power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a pre-reactor stage is introduced to convert part of synthesis gas into methanol, then the amount of synthesis gas that needs to be compressed is reduced, but the investment costs and operating costs of the pre-reactor itself increase
Solution Approach 1:
The pre-reactor performs preliminary conversion of synthesis gas to methanol before the main compression stage, reducing the volume of gas that needs to be compressed by the synthesis gas compressor. This preliminary action occurs at lower pressure conditions where conversion is more efficient.
Solution Approach 2:
The process uses a simplified pre-reactor stage that replicates the essential catalytic conversion function on a smaller scale, allowing partial methanol production before the main reactor stage. This copying approach enables energy savings without requiring a complete redesign of the methanol synthesis system.
2Productivity
If the carbon monoxide content in feed gas is increased to 25-36% by volume, then methanol conversion in the pre-reactor is enhanced and compressor power is reduced, but the composition control of feed gas becomes more critical
Solution Approach 1:
The process optimizes the carbon monoxide content parameter in the feed gas to a specific range of 25-36% by volume. This parameter change enhances the thermodynamic favorability of methanol synthesis in the pre-reactor, improving conversion efficiency and reducing the workload on downstream compressors.
3Quantity of substance
If gas compressors are sized to handle the full amount of synthesis gas, then all synthesis gas can be processed, but the compressor size and power consumption increase significantly
Solution Approach 1:
The synthesis gas processing is segmented into two stages: a pre-reactor stage that handles a portion of the gas at lower pressure, and a main reactor stage that processes the remaining gas after compression. This segmentation allows the compressor to handle only the unconverted residual gas, significantly reducing power consumption while maintaining complete gas processing.
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 leads to substantial energy savings and reduced compressor size, lowering operational and capital expenditures by increasing methanol conversion in the pre-reactor stage and reducing the amount of residual gas that needs to be compressed, thereby decreasing overall compressor power and costs.
Implementation Method 1
catalytic conversion of the feed gas into a first methanol-containing product stream
Implementation Method 2
methanol is separated from the first methanol-containing product stream and discharged from the pre-reactor stage
Implementation Method 3
residual gas of the remaining feed gas stream is compressed as a residual gas stream to reaction pressure
Implementation Method 4
residual gas stream is introduced into a main reactor stage for catalytic conversion into a second methanol-containing product stream
Data Source
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AI summary
The invention relates to a process and a plant for the production of methanol from a feed gas containing carbon monoxide (CO) and hydrogen (H2) using a pre-reactor stage and a main reactor stage. Feed gas, generated under elevated pressure and kept stationary, is first introduced into a pre-reactor stage for catalytic conversion into a first methanol-containing product stream. After separation of methanol from the first methanol-containing product stream and discharge from the pre-reactor stage, a remaining gas stream, after compression to reaction pressure, is introduced into a main reactor stage for catalytic conversion into a second methanol-containing product stream. After separation from the second methanol-containing product stream, methanol is discharged from the main reactor stage. When using a feed gas with a carbon monoxide content of 25 vol.% to 36 vol.%, the process is described in more detail below.-% results in significant savings in terms of the compressor power required for the manufacturing process.