Sloped Vapor Generator Heating Surface for Stable Low-Flow Evaporation

Solution Overview

Problem

Existing vapor generators for high-temperature electrochemical converters face challenges in maintaining a constant vapor flow rate at low flow rates (10 g/hr to 10 kg/hr) without using carrier gases, often resulting in vapor puffs and pressure fluctuations that can damage the electrochemical cells.

Innovation Solution

A vapor generator design featuring a heating surface with a downward slope and a U-shaped corner piece around a heat transfer pipe, which ensures continuous evaporation and controlled vapor production by adjusting the slope, heating power, and length of the heating surface, eliminating the need for carrier gases and vapor flow control valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a heating tube or heated volume is used to evaporate water at low flow rates, then the vapor flow rate can be regulated, but vapor puffs and overpressures occur causing instability

Engineering Contradiction:

Improvevapor flow rateVSAvoidoperational stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The heating surface is designed with non-uniform properties: the lower portion has higher heating power density to ensure complete evaporation, while the upper portion has lower heating power density to prevent local overheating and vapor puffs. This gradient in heating intensity matches the liquid flow pattern and evaporation requirements along the downward slope.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system uses a downward sloping heating surface that creates dynamic liquid flow driven by gravity. The liquid continuously moves from the upper to lower portion, creating a dynamic equilibrium where evaporation occurs along the flow path without stagnation or localized boiling runaway.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the heating power is increased to maintain vapor flow rate, then productivity improves, but local boiling and runaway reactions occur

Engineering Contradiction:

Improvevapor flow rateVSAvoidlocal overheating

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The heating surface is designed with non-uniform properties: the lower portion has higher heating power density to ensure complete evaporation, while the upper portion has lower heating power density to prevent local overheating and vapor puffs. This gradient in heating intensity matches the liquid flow pattern and evaporation requirements along the downward slope.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The downward sloping design ensures continuous liquid flow across the heating surface, preventing stagnation and ensuring that evaporation occurs continuously along the flow path. This continuous action distributes the heating effect evenly over time and space, preventing localized thermal runaway.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If vapor flow rate is increased to meet demand, then productivity improves, but pressure fluctuations damage electrochemical cells

Engineering Contradiction:

Improvevapor flow rateVSAvoidpressure fluctuations

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The downward sloping design ensures continuous liquid flow across the heating surface, preventing stagnation and ensuring that evaporation occurs continuously along the flow path. This continuous action distributes the heating effect evenly over time and space, preventing localized thermal runaway.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system changes the geometric parameter of the heating surface (downward slope) to fundamentally alter the flow and evaporation characteristics. This geometric change transforms the evaporation process from discrete bubble formation to continuous film evaporation, stabilizing pressure and flow rate.

Inventive Principle:

Principle #35Parameter changes

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 solution achieves a constant and regular vapor flow rate, preventing vapor puffs and pressure fluctuations, thus extending the lifespan of the electrochemical cells and maintaining stable operation at low flow rates.

Implementation Method 1

a heating surface (12) with a downward slope arranged in said enclosure and defining a liquid flow path; a heat transfer pipe configured to allow the flowing of a heat transfer fluid to heat said heating surface

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The liquid entirely covers the heat transfer pipe in the upper portion of the heating surface... enable to limit the phenomenon of water drops sliding on the vapor bed and a continuous evaporation of the liquid is obtained

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11614228B2Device for converting a liquid to a vapour

Publication Date: 2023.03.28 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A device for converting a liquid into vapor includes an enclosure, a heating surface with a downward slope arranged in the enclosure, and a liquid inlet port connected to an upper portion of the heating surface so that a liquid introduced from the liquid inlet port flows on the heating surface. The device also includes a vapor outlet port formed through a wall of the enclosure. The heating surface includes a heat transfer pipe configured to allow the flowing of a heat transfer fluid to heat the heating surface, and a corner piece including a U-shaped cross-section with a semi-circular portion arranged around the heat transfer pipe and an upper portion forming an opening on the enclosure.