Methanol Plant Synthesis Gas Module Optimization
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Solution Overview
Problem
Methanol production processes face inefficiencies due to suboptimal synthesis gas composition and inert content, leading to reduced methanol output and increased energy consumption, particularly in existing facilities that rely on conventional steam methane reforming methods.
Innovation Solution
The method involves producing a first stream of synthesis gas with a module greater than 2.0 using steam methane reforming and a second stream with a lower module through partial oxidation or autothermal reforming, combining these streams to achieve an optimal module for methanol synthesis, and recycling purge gas to enhance the process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam methane reforming is used to produce synthesis gas, then the process is well-established and reliable, but the synthesis gas composition is suboptimal with high inert content leading to reduced methanol output
Solution Approach 1:
The patent combines two different synthesis gas production methods (steam methane reforming and partial oxidation/autothermal reforming) into a single integrated system. The SMR unit produces synthesis gas with higher hydrogen content while the POx/ATR unit produces synthesis gas with lower inert content. By merging these streams and adjusting their ratios, the system achieves optimal synthesis gas composition for methanol production, resolving the contradiction between maintaining reliable conventional processes and improving productivity.
Solution Approach 2:
The patent changes the compositional parameters of synthesis gas by introducing a second production route with different characteristics. The POx/ATR process produces synthesis gas with lower inert content and different H2/CO ratio compared to conventional SMR. By adjusting the mixing ratio and operational parameters of the two units, the system optimizes the module value and inert content to improve methanol output while maintaining process reliability.
2Reliability
If higher purge flow is used to remove inerts from the synthesis gas, then inert buildup in the methanol converter is prevented, but hydrogen and methane slip are lost increasing energy consumption
Solution Approach 1:
The patent recovers valuable hydrogen and methane that would otherwise be discarded in the purge stream. The POx/ATR unit processes the purge gas or feedstock to convert these components into useful synthesis gas products. This approach allows the system to maintain adequate purge flow for preventing inert buildup while simultaneously recovering the energy value of hydrogen and methane slip, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The patent converts the harmful effect of inert buildup and the waste of hydrogen/methane slip into a benefit by using the POx/ATR unit to process these streams. The unit transforms the purge gas containing lost hydrocarbons into valuable synthesis gas, turning the waste stream into a resource that improves overall process efficiency and reduces energy consumption while maintaining converter performance.
3Productivity
If synthesis gas with module greater than 2.0 is produced, then hydrogen content is high favoring methanol formation, but the stoichiometric ratio is suboptimal requiring adjustment
Solution Approach 1:
The patent implements a dynamic system where the mixing ratio between SMR and POx/ATR synthesis gas streams can be adjusted to achieve the optimal module value. The system continuously adapts the composition by varying the contribution of each unit based on operational conditions, allowing maintenance of optimal stoichiometric ratio while preserving high hydrogen content for improved methanol formation rate.
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 output by 20% and reduces specific natural gas consumption by 1.4%, improving overall process efficiency while maintaining comparable unreacted gas flow rates, thus enhancing the existing facility's performance without requiring additional compression.
Implementation Method 1
producing a first stream of synthesis gas having a module greater than 2.0, in a steam methane reformer (SMR) or in a steam methane reformer followed by an autothermal reformer, by reforming a first hydrocarbon feed stream and steam in the presence of a catalyst
Implementation Method 2
producing a second stream of synthesis gas having a module less than that of the first stream of synthesis gas, by partial oxidation or autothermal reforming of a second hydrocarbon feed stream
Implementation Method 3
producing a second stream of synthesis gas having a module less than that of the first stream of synthesis gas, by partial oxidation or autothermal reforming of a second hydrocarbon feed stream
Implementation Method 4
synthesizing the combined synthesis gas product stream in a methanol synthesis reactor into a product composition comprising methanol
Data Source
AI summary
A method and system for producing methanol that employs steam methane reforming (SMR) and/or autothermal (ATR) synthesis gas production system, together with a partial oxidation system, is disclosed. The dual mode system and method for producing the synthesis gas in a methanol production process optimizes the efficiency and productivity of the methanol plant by using the partial oxidation based reforming system as an independent source of synthesis gas. The disclosed methods and systems are configurable either as a retrofit to existing methanol production facilities or as an integrated package into newly constructed methanol production facilities.