Refining system and method for refining a feed gas stream
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Solution Overview
Problem
Current methods for refining natural gas streams with high CO2 content, such as absorption, cryogenic cooling, and membrane technology, face inefficiencies and challenges including high CO2 emission volumes, excessive cooling requirements, and sensitivity to hydrocarbons and fouling issues, making them impractical for large-scale gas fields.
Innovation Solution
A refining system and method involving dehydration, pre-cooling, fractionation, expansion cooling, and crystallization to separate CO2 from natural gas, utilizing a supersonic cyclonic fluid separator to achieve efficient CO2 depletion and hydrocarbon recovery, with expansion cooling enhancing efficiency at low temperatures and crystallization producing solid CO2 for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If absorption process is used to remove CO2 from natural gas streams, then CO2 can be selectively dissolved in solvent, but efficiency decreases when CO2 concentration exceeds 30 mole %
Solution Approach 1:
The patent changes the fundamental parameter of CO2 separation from chemical absorption to physical phase separation through cooling. By lowering temperature to below the dew point, the system transforms the separation mechanism from solvent-based absorption to temperature-driven condensation, enabling effective handling of high CO2 concentrations (30-100 mole %) that are incompatible with traditional absorption processes
Solution Approach 2:
The invention utilizes phase transition of CO2 from gas to liquid (or solid) state through cooling below dew point temperature. This phase change enables direct separation of CO2 from natural gas without requiring chemical solvents, resolving the efficiency limitation of absorption processes at high CO2 concentrations
2Quantity of substance
If CO2 is removed by absorption process, then CO2 can be separated from natural gas, but large volume of CO2 gas is produced requiring sequestration or further processing
Solution Approach 1:
The patent applies phase transition by cooling the gas stream below dew point temperature to condense CO2 directly into liquid or solid form. This eliminates the generation of large volumes of CO2 gas that characterizes absorption processes, as CO2 is separated in condensed phase and can be directly stored or utilized without requiring sequestration infrastructure
Solution Approach 2:
By changing the temperature parameter to below dew point conditions, the system transforms CO2 from gaseous state to condensed state during separation. This parameter change fundamentally alters the output form from CO2 gas (requiring sequestration) to CO2 liquid/solid (amenable to direct storage or utilization)
3Quantity of substance
If membrane technology is used for CO2 removal, then CO2 can be selectively transported through membrane, but light hydrocarbons slip into permeate stream requiring further treatment
Solution Approach 1:
The patent uses phase transition through cooling to separate CO2 in condensed form, creating a clear phase boundary between CO2 (liquid/solid) and hydrocarbons (gas). This physical separation mechanism is inherently more selective than membrane transport, preventing light hydrocarbon slip into the CO2 stream and eliminating the need for permeate re-treatment
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 system effectively reduces CO2 emissions, minimizes hydrocarbon losses, and operates efficiently at low temperatures, producing a CO2-depleted gas stream and a pure CO2 stream, addressing the limitations of existing technologies by optimizing separation and recovery processes.
Implementation Method 1
a dehydration unit for dehydrating the feed gas stream, capable of obtaining a water dew point of the feed gas stream between −45° C. and −65° C.
Implementation Method 2
the pre-cooling section being arranged for pre-cooling the received feed gas stream below a dew point of the gas such that a mixed stream comprising a liquid enriched with the second component and gas stream enriched with the first component is formed
Implementation Method 3
pre-cooling the received feed gas stream below a dew point of the gas such that a mixed stream comprising a liquid enriched with the second component
Implementation Method 4
the fractionation section having being arranged for fractionating the pre-cooled mixed stream into a first fractionated stream of gas enriched with the first component at a first separation outlet and a second fractionated stream of a liquid enriched with the second component at a second separation outlet
Implementation Method 5
expanding the first fractionated gas stream, thereby further cooling the first fractionated gas stream to a temperature and pressure below the dew point of the gas
Implementation Method 6
a fluid separator device, being arranged for—at an inlet receiving the first fractionated gas stream,—expanding the first fractionated gas stream
Implementation Method 7
a crystallization separator vessel coupled to the second outlet of the separator, arranged for receiving the second flow of the separator and for separating the further liquid enriched with the second component from the second flow of the cooled high density fluid fraction, wherein the crystallization separator vessel being arranged for solidifying the second component from the second flow of the cooled high density fluid fraction, the second component solids being melted in the bottom section of the crystallization vessel
Data Source
AI summary
A refining system for refining a feed gas (10) includes a first and a second component, the first component having a lower dew point temperature than the second component; the refining system including:—an input section (105) for input of the feed gas including a dehydration unit for dehydrating the feed gas, capable of obtaining a water dew point between −45 and −65° C.;—a pre-cooling section (110) coupled to the input section for receiving the dehydrated feed gas;—a fractionation section (115) coupled to the pre-cooling section for receiving the pre-cooled stream;—an expansion cooling and separation section (120) coupled to the fractionation section for receiving the fractionated gas, including a cyclonic separator device (240); the expansion cooling and separation section having an reflux conduit coupled to the fractionation section for reflux (24) of liquid enriched with the second component to the fractionation section.