Compact CO2 Removal Assembly for Hydrocarbon Gas Separation
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Solution Overview
Problem
Existing processes for removing carbon dioxide from gas streams containing hydrocarbons are economically inefficient due to high capital and operating costs, especially at high carbon dioxide concentrations, and often result in the loss of lighter hydrocarbons during bulk removal processes.
Innovation Solution
A compact distillation process that integrates multiple equipment items into a single housing, reducing capital costs and power consumption, while achieving efficient carbon dioxide removal by fractionating gas streams to separate carbon dioxide from hydrocarbons, allowing for the recovery of carbon dioxide as a liquid for subsequent use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple equipment items are used for carbon dioxide removal, then separation efficiency is improved, but device complexity and capital cost increase
Solution Approach 1:
The patent combines multiple separate equipment items (distillation column, heat exchangers, compressors, separators) into a single integrated processing assembly. This merging maintains the functional complexity needed for effective carbon dioxide removal while simplifying the overall system architecture, reducing capital costs, and eliminating the need for extensive piping and flanged connections between separate units.
2Manufacturing precision
If conventional distillation processes are used, then carbon dioxide separation is achieved, but energy consumption is high
Solution Approach 1:
The patent implements preliminary cooling and condensation of the gas stream before it enters the distillation column. By pre-cooling the feed gas and pre-condensing carbon dioxide, the system reduces the energy burden on the distillation column itself, thereby lowering overall power consumption while maintaining effective separation efficiency.
Solution Approach 2:
The processing assembly uses its own output streams to provide cooling and heating for its input streams. The cold liquid carbon dioxide stream cools the incoming gas, and the warmed liquid from the distillation column provides heating for the reboiler, creating a self-sustaining thermal system that minimizes external energy input.
3Productivity
If bulk removal processes are used, then carbon dioxide removal is efficient, but lighter hydrocarbons are lost
Solution Approach 1:
The patent applies local quality by creating different separation zones within the distillation column, with specific tray configurations and operating conditions optimized for different components. The upper section of the column is optimized for carbon dioxide removal while the lower section maintains conditions that prevent lighter hydrocarbon condensation and loss, allowing selective separation based on local conditions in different parts of the 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
The process effectively removes over 87% of carbon dioxide while retaining over 99% of methane, reducing energy consumption and capital costs, and minimizing environmental emissions by eliminating flanged piping connections, thus enhancing processing efficiency and reducing atmospheric emissions.
Implementation Method 1
A better alternative for bulk removal of carbon dioxide is to use distillation to fractionate the gas stream into a light hydrocarbon stream and a carbon dioxide stream
Implementation Method 2
The majority of the carbon dioxide that is removed is recovered as a liquid rather than a vapor, allowing the carbon dioxide to be pumped (rather than compressed) for subsequent use
Data Source
AI summary
A process and an apparatus are disclosed for a compact processing assembly to remove carbon dioxide from a hydrocarbon gas stream. The gas stream is cooled, expanded to intermediate pressure, and fed to the top of a mass transfer means. A distillation liquid stream from the mass transfer means is heated in a first heat and mass transfer means to strip out its volatile components and form a bottom liquid product. A distillation vapor stream from the mass transfer means is combined with any vapor in the expanded cooled gas stream, and the combined vapor stream is cooled in a second heat and mass transfer means to partially condense it, forming a condensed stream that is fed to the top of the mass transfer means. A portion of the bottom liquid product is subcooled, expanded to lower pressure, and used to cool the combined vapor stream.