Methanol Loop Revamp Using Electrically Heated RWGS Reactor
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Solution Overview
Problem
Existing methanol production processes face challenges due to high water by-production, catalyst deactivation, and the need for large reactor volumes and compressor throughput, especially when using CO2 as the sole carbon feedstock.
Innovation Solution
The implementation of an electrically heated Reverse Water Gas Shift (e-RWGS) reactor upstream of the methanol synthesis section, which shifts CO2 to CO, reducing the amount of synthesis gas required and allowing for more efficient compression and processing, thereby reducing operational costs and enabling the use of sustainable electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CO2 is used as the sole carbon feedstock in methanol synthesis, then the process is simpler and more direct, but water by-production increases significantly and catalyst deactivation accelerates
Solution Approach 1:
The invention divides the single-step methanol synthesis process into two distinct stages: first, a reverse water-gas shift reaction stage that converts CO2 to CO with minimal water production, followed by a methanol synthesis stage. This segmentation allows each reaction to be optimized independently, solving the problem of excessive water by-production while maintaining process simplicity.
Solution Approach 2:
The invention introduces CO as an intermediate substance in the methanol production process. By first converting CO2 to CO through the reverse water-gas shift reaction, and then using CO as the carbon source for methanol synthesis, the process avoids direct CO2 hydrogenation that produces excessive water, thereby reducing catalyst deactivation.
2Productivity
If the methanol synthesis section is designed to handle high CO2 concentrations, then CO2 utilization is maximized, but reactor volume and compressor throughput must be significantly increased
Solution Approach 1:
The invention performs the reverse water-gas shift reaction as a preliminary step before methanol synthesis. This preliminary action converts CO2 to CO and reduces the gas volume, allowing the subsequent methanol synthesis section to operate with smaller reactor volume and compressor throughput while still achieving high CO2 utilization through the two-stage process.
3Temperature
If a fired RWGS reactor is used for CO2 shift, then the reaction can proceed at high temperature, but CO2 emissions from fuel combustion increase
Solution Approach 1:
The invention replaces the thermal field (fuel combustion) with an electrical field (electric heating) in the RWGS reactor. By using electric heating instead of fired heating, the process can maintain the high reaction temperature needed for effective CO2 shift while eliminating CO2 emissions from fuel combustion, thus substituting a mechanical/chemical system with an electrical system.
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 increases methanol production capacity, reduces catalyst deactivation, and decreases water content in the product, allowing for more efficient use of existing equipment and lower operational costs while minimizing CO2 emissions.
Implementation Method 1
an electrically heated RWGS reactor can be operated at a higher temperature than a fired RWGS reactor, and that hence the RWGS reaction can be shifted to form more CO and water
Implementation Method 2
an electrically heated RWGS reactor can be operated at a higher temperature than a fired RWGS reactor
Data Source
AI summary
A methanol plant is provided in which a first feed comprising CO2 and a second feed comprising H2 are provided, the combined feed is shifted in a CO2 shift unit so as to provide a first synthesis gas stream. Water is removed in a water removal unit, to provide a second synthesis gas stream. A methanol synthesis section receives the second synthesis gas stream, and provides a product stream comprising methanol. A process for producing a product stream comprising methanol, and a process for upgrading a methanol plant are also provided.