Longitudinal Shell-Side Flow in Syngas Reforming Reactors
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Solution Overview
Problem
Current reforming exchanger designs for syngas production are costly due to the use of expensive alloys and result in high capital costs and large equipment sizes, with inefficient heat transfer and uneven temperature profiles leading to suboptimal reforming kinetics.
Innovation Solution
A longitudinal shell-side flow configuration with a countercurrent flow arrangement, utilizing a tube bundle with longitudinally-spaced transverse ring baffles and lattice support assemblies, and catalyst-bearing monolithic structures within the tubes, which reduces the shell diameter and pressure drop while maintaining efficient heat transfer and uniform temperature profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive alloys are used in tube bundle and tube sheets construction, then reliability is improved, but capital cost increases
Solution Approach 1:
The patent changes the material parameter from expensive alloys to cheaper materials like stainless steel or Incoloy, while adjusting operating parameters (temperature, pressure) to remain within the reduced material's safe operating limits, thus achieving cost reduction without sacrificing reliability
Solution Approach 2:
The patent employs cheaper, more readily available materials for the tube bundle and tube sheets, accepting that these components may have shorter service lives and require more frequent replacement, thereby reducing capital costs while maintaining operational reliability through proactive maintenance
2Productivity
If tube diameter is decreased to increase surface area to volume ratio, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the tube bundle into many small-diameter tubes instead of using fewer large-diameter tubes, increasing the total surface area to volume ratio and improving heat transfer efficiency and productivity, while the modular nature of the segmentation keeps the overall design manageable
Solution Approach 2:
The patent transitions from a single-dimension approach (large tube diameter) to a multi-dimension approach (many small tubes arranged in a compact bundle), increasing surface area without proportionally increasing volume, thus improving productivity while controlling device complexity through optimized spatial arrangement
3Power
If five or more shell-side cross passes are used, then heat transfer efficiency is improved, but shell-side pressure drop increases
Solution Approach 1:
The patent introduces adjustable or variable shell-side flow distribution mechanisms that can dynamically optimize the flow pattern across the tube bundle, allowing the system to adapt the effective number of cross passes based on operating conditions, thus maintaining heat transfer efficiency while controlling pressure drop
Solution Approach 2:
The patent modifies the flow distribution parameters through optimized baffle designs and inlet/outlet arrangements, changing the flow pattern from simple cross-flow to a more complex but more efficient three-dimensional flow pattern that achieves better heat transfer with lower pressure drop than traditional multi-pass designs
4Stress or pressure
If fewer shell-side passes are used to reduce pressure drop, then shell-side pressure drop is reduced, but temperature profile uniformity deteriorates
Solution Approach 1:
The patent implements localized flow distribution and temperature control measures, such as multiple inlet and outlet points strategically positioned around the shell, creating locally optimized flow patterns that ensure uniform temperature distribution across the tube bundle while maintaining low overall pressure drop
Solution Approach 2:
The patent introduces intermediate flow distribution elements such as perforated plates or flow distributors that act as mediators between the shell-side inlet and the tube bundle, ensuring uniform flow distribution and temperature profiling without requiring multiple complex cross passes, thus maintaining low pressure drop while achieving temperature uniformity
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 design minimizes capital costs, increases the reforming exchanger's capacity, and facilitates easier maintenance by reducing the size and weight of the equipment, while achieving efficient heat transfer and uniform temperature profiles, thus enhancing the overall efficiency and effectiveness of the syngas production process.
Implementation Method 1
catalyst-filled tubes
Implementation Method 2
The combustion reaction is exothermic and supplies the heat needed for the catalytic reforming reaction that occurs in the autothermal reformer, which is endothermic
Implementation Method 3
The hot gas from the autothermal reformer is then used as a heat source in the reforming exchanger, which is operated as an endothermic catalytic steam reforming zone
Implementation Method 4
The hot gas mixture is then passed countercurrently across the tubes in indirect heat exchange to supply the heat necessary for the endothermic reforming reaction
Implementation Method 5
Steam reforming of a hydrocarbon to manufacture syngas is a process in which the hydrocarbon and an oxygen source are supplied to an autothermal reformer. The combustion reaction is exothermic and supplies the heat needed for the catalytic reforming reaction
Data Source
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AI summary
A syngas reforming reactor has a shell-and-tube configuration wherein the shell-side fluid flow path through the tube bundle has a longitudinal configuration. The reactor can include a shell-side inlet fluid distributor plate below the lower end of the tube bundle, and a flow sleeve in an enlarged-diameter discharge annulus at an upper end adjacent the tube sheet to prevent short-circuiting of the shell-side fluid into the shell-side fluid outlet. The tube bundle can include a plurality of ring baffles and lattice baffles. The longitudinal flow configuration can provide a lower shell-side pressure drop and lower cost compared to a conventional cross-flow reforming exchanger