GTL Tail Gas CO2 Separation for Light Ends Recovery
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Solution Overview
Problem
The tail gas from gas-to-liquid (GTL) plants contains diluting species like N2 and Ar, which reduce the concentration of reactants, leading to larger equipment requirements and undesirable by-products, and lacks optimal composition for fuel or CO2 source use.
Innovation Solution
A process that separates CO2 from the tail gas, recovering light ends and utilizing the separated CO2 as a feed stream to the syngas reactor, while using work-producing gas expanders for refrigeration and compression to enhance energy integration and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tail gas is used as fuel or CO2 source without separation, then it can be utilized, but the presence of N2 and Ar dilutes reactant concentration leading to larger equipment and undesirable by-products
Solution Approach 1:
The patent extracts and separates CO2 from the tail gas stream using absorption towers and distillation columns, removing the diluting effect of N2 and Ar while concentrating the useful CO2 component for reuse in the reforming process
Solution Approach 2:
The patent changes the composition parameters of the tail gas by selectively removing CO2 through chemical absorption and thermal distillation, transforming it from a diluted waste stream into a concentrated feedstock for the syngas reactor
2Ease of operation
If N2 and Ar are present in tail gas, then they are carried through the process, but they dilute reactants and may form undesirable HCN and NH3 by-products
Solution Approach 1:
The patent converts the potentially harmful concentrated CO2 that would otherwise be emitted as greenhouse gas into a valuable feedstock for the reforming process, while simultaneously eliminating the formation of harmful by-products by removing inert diluents
3Productivity
If tail gas composition is not optimized, then it can be used as fuel, but the diluting species require larger equipment size
Solution Approach 1:
The patent extracts CO2 from the tail gas and concentrates it, reducing the volume of gas that needs to be handled in downstream equipment while improving the energy density and utilization efficiency of the fuel stream
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 process improves the utilization of tail gas by recovering valuable light ends and CO2, reducing greenhouse gas emissions, and optimizing syngas chemistry, thereby enhancing the efficiency and reducing equipment size of the GTL plant operations.
Implementation Method 1
utilizing work-producing gas expanders for refrigeration and compression
Implementation Method 2
separating CO2 from the light products in the tail gas
Data Source
AI summary
The GTL process of the invention comprises: reacting a combustible carbonaceous material in a syngas reactor, preferably an autothermal reformer, under conditions to produce a synthesis gas; contacting the synthesis gas with an F-T catalyst to form liquid products and a tail gas; separating the tail gas from the liquid products; separating CO2 from the light products in the tail gas; recovering the light products as additional products for sale or other use and utilizing at least a portion of the separated CO2 as a feed stream to the syngas reactor.