Conduit with Annular Flexible Ring for Cooling Hydrocarbon Streams
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Solution Overview
Problem
Current methods for cooling hydrocarbon gas-containing streams after pyrolysis, such as direct quenching, face challenges like high quench fluid requirements, costly separation and treatment, and fouling issues due to coke deposition, which increase energy consumption and operational complexity.
Innovation Solution
A conduit design featuring an annular flexible ring and a quench fluid introduction system that allows for controlled distribution of quench fluid within an annular cavity, preventing fouling by maintaining a liquid seal and reducing the need for high volumes of quench fluid, while accommodating thermal expansion of the conduit walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If direct quench is performed by introducing quench fluid through the tube wall, then cooling efficiency is improved, but quench fluid volume requirement increases significantly
Solution Approach 1:
The conduit is divided into multiple bore sections (first bore, second bore, third bore) with quench fluid introduction ports positioned at different locations. This segmentation allows localized cooling at critical sections where dew-point fouling occurs, rather than requiring uniform cooling throughout the entire conduit, thereby reducing overall quench fluid volume while maintaining effective cooling where needed.
Solution Approach 2:
Quench fluid is introduced at specific locations (first, second, and third introduction ports) corresponding to different thermal zones along the conduit. The first port introduces quench fluid near the hot effluent entry to prevent initial condensation fouling, the second port provides cooling in the intermediate zone, and the third port addresses cooling near the conduit exit. This localized quality approach ensures cooling is applied precisely where temperature gradients and fouling risks are highest, optimizing cooling efficiency while minimizing quench fluid consumption.
2Object-affected harmful factors
If high volume of quench fluid is used for direct quench, then fouling prevention is improved, but separation and treatment cost increases
Solution Approach 1:
Quench fluid is introduced in advance at the first introduction port before the hydrocarbon effluent reaches the critical cooling zone where dew-point fouling would occur. This preliminary action of quenching the effluent early in the cooling process prevents condensation and subsequent fouling from occurring in the first place, rather than requiring large volumes of quench fluid to be injected later to address fouling problems. The preliminary quenching action maintains fouling prevention while reducing overall quench fluid requirements.
3Ease of operation
If quench fluid is injected through small nozzle openings, then dispersion is improved, but nozzle plugging with polymer and coke particles occurs
Solution Approach 1:
Instead of injecting quench fluid through small openings in the tube wall (zero-dimensional point injection), the invention introduces quench fluid through ports in the conduit ends and uses the annular bore geometry to distribute fluid along the length of the conduit (one-dimensional linear distribution). This dimensional change from point injection to distributed injection eliminates the plugging problem associated with small nozzle openings while maintaining effective dispersion of quench fluid throughout the hydrocarbon effluent stream.
4Quantity of substance
If pipe sizing is increased to accommodate high quench fluid volumes, then quench fluid capacity is improved, but circulation pump size and energy consumption increase
Solution Approach 1:
The cooling function is segmented into multiple zones along the conduit length, with quench fluid introduction ports positioned to address fouling prevention in each zone. This segmentation allows the system to use smaller pipe diameters and lower quench fluid volumes compared to a single large-diameter pipe design, thereby reducing the size and energy consumption of circulation pumps while maintaining adequate cooling capacity throughout the conduit.
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 conduit design effectively cools hydrocarbon gas streams with reduced quench fluid usage, minimizing fouling and operational costs, and allows for efficient thermal management, thereby improving the efficiency and reliability of the cooling process.
Implementation Method 1
contacting the hydrocarbon gas-containing stream with the quench fluid within the second bore to produce a cooled effluent
Implementation Method 2
permitting the first inner sidewall to thermally change dimensions both radially and axially with respect to a longitudinal axis of the first bore
Data Source
AI summary
Conduits for cooling a hydrocarbon stream and processes for using same. The conduit can include a first inner wall defining a first bore, a second inner wall defining a second bore, and an outer wall disposed about the first and second inner walls. The conduit can also include an annular support wall connected to an inner surface of the outer wall. An end of the second inner wall and an end of the annular support wall can define a perimeter opening that can be in fluid communication with the second bore. An annular flexible ring can be bonded to the annular support wall and can flexibly contact the first inner wall. A substantially annular cavity can be disposed between the second inner and the outer walls and in fluid communication with the perimeter opening. A quench fluid introduction port can be configured to introduce a quench fluid into the cavity.