Waste Heat Boiler Outlet Nozzle for Corrosion Prevention
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Solution Overview
Problem
Existing waste heat boilers face corrosion issues due to 'metal dusting' at high temperatures in gas generation plants, particularly in steam reforming and autothermal reforming processes, where conventional solutions are either expensive, complex, or prone to mechanical failures, leading to short maintenance intervals and material degradation.
Innovation Solution
A waste heat boiler design featuring a cylindrical shell with heat transfer tubes and a bypass tube, where the bypass tube's outlet end connects to a kinked mouthpiece that creates a rotating flow within the outlet chamber, allowing for effective mixing of cooled and uncooled gases, reducing corrosion risk and enabling the use of standard materials, and incorporating a ceramic closure device for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional materials are used in the outlet chamber, then manufacturing cost is reduced, but corrosion occurs due to metal dusting at high temperatures
Solution Approach 1:
The patent converts the harmful hot gas stream into a beneficial rotating flow pattern. By directing the hot gas stream tangentially along the outlet chamber wall, the design creates a vortex that prevents direct contact between hot gases and the chamber wall, thereby eliminating corrosion while allowing use of conventional materials.
Solution Approach 2:
The patent introduces an intermediary flow pattern (rotating/vortex flow) between the hot gas stream and the outlet chamber wall. This intermediary flow acts as a protective barrier that prevents the harmful direct contact and heat transfer that would cause metal dusting and corrosion.
2Device complexity
If the bypass tube outlet is directed directly into the outlet chamber, then device complexity is reduced, but hot gas strands break through and cause damage downstream
Solution Approach 1:
The patent employs curved/tangential geometry in the bypass tube outlet design. Instead of a direct linear outlet, the gas stream is directed tangentially along the outlet chamber wall, creating a curved flow path that prevents straight hot gas strands from breaking through to downstream components.
Solution Approach 2:
The patent transitions from a one-dimensional direct outlet to a two-dimensional tangential flow pattern along the chamber wall. This dimensional change creates a rotating flow structure that distributes the hot gas stream along the wall surface rather than allowing direct penetration downstream.
3Measurement precision
If control plates are used to regulate product gas temperature, then temperature control precision is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent employs a self-regulating flow distribution system where the rotating flow pattern naturally mixes hot and cooled gas streams. The system automatically achieves proper temperature mixing without requiring complex external control plates or additional control mechanisms, thereby simplifying the overall device while maintaining temperature control precision.
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 effectively prevents corrosion by ensuring rapid mixing of gas fractions, allowing the use of standard materials and minimizing maintenance downtime, while the ceramic components and automatic closure ensure operational reliability and long operational intervals.
Implementation Method 1
the gas stream is passed through the heat transfer tubes while being cooled in indirect heat exchange with water on the shell side
Implementation Method 2
cooled in indirect heat exchange with water on the shell side
Implementation Method 3
the water being at least partially vaporized
Implementation Method 4
water being at least partially vaporized
Implementation Method 5
creates a rotating flow within the outlet chamber, allowing for effective mixing of cooled and uncooled gases
Data Source
Figure 1a~1b
AI summary
The boiler has an inlet (1) and an inlet chamber (2) for introducing a hot gas stream into an inlet end of a bypass pipe (3). The gas stream is passed through a heat transfer tube (4), and is cooled in indirect heat exchange with water at a side of a shell (11). An outlet (10) and an outlet chamber (9) discharge the cooled exhaust gas stream. The outlet is opened in a nozzle (7) that is deviated into the outlet chamber. A center line of the bypass pipe includes a bend angle with a longitudinal axis of the boiler. An end of the nozzle is fixed with a closure device i.e. closure flap. The nozzle and the closure device are made of ceramic materials. An independent claim is also included for a method for cooling hot synthesis gas.