Heat Recovery from Combustion Gases via Compressor Condensation

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Solution Overview

Problem

Current technologies fail to effectively recover maximum latent and sensible heat from combustion gases due to limitations in condensation processes, particularly at high pressures and temperatures, leading to inefficiencies in energy recovery and safety concerns from gas leaks.

Innovation Solution

A device comprising a primary circuit for compressing and condensing combustion gases, with a heat transfer fluid circuit to recover heat, utilizing a compressor to achieve pressures near water vapor saturation, and a droplet separator to manage condensate, enabling efficient heat transfer and pollutant capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If combustion gases are compressed to recover maximum latent heat, then energy recovery efficiency is improved, but the complexity of the device increases

Engineering Contradiction:
Improvelatent heat recoveryVSAvoidcompression system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the compression function and heat exchange function into an integrated system where the compressor and heat exchanger work in close proximity, allowing the combustion gases to be compressed and simultaneously have their latent heat recovered through condensation, reducing the need for separate independent systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchanger serves multiple functions: it acts as a condensation surface for latent heat recovery, a heat transfer medium for energy capture, and a component that facilitates both cooling and phase change processes in a single device, thereby reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of energy

If the temperature of heating water return circuit is reduced to enable full condensation, then latent heat recovery is improved, but the productivity of hot water production decreases

Engineering Contradiction:
Improvelatent heat recoveryVSAvoidhot water production
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent segments the heat recovery process into distinct stages: first recovering latent heat through condensation at lower temperatures, then recovering sensible heat at higher temperatures, allowing both functions to operate effectively without mutual interference

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts temperature parameters across different sections of the heat exchanger, maintaining low temperatures in condensation zones to maximize latent heat recovery while preserving higher temperatures in other zones to ensure adequate hot water production capability

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If combustion gases are cooled for heat recovery, then energy efficiency is improved, but the temperature of treated gases decreases requiring additional heating

Engineering Contradiction:
Improveheat recovery efficiencyVSAvoidoutlet gas temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent converts the harmful effect of excessive cooling (which would require reheating) into a benefit by precisely controlling the cooling process to stop at the optimal point where maximum heat recovery is achieved while maintaining sufficient outlet temperature, using the cooling process itself to drive the heat recovery rather than requiring separate heating operations

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enables the recovery of up to 100% of latent and sensible heat, improving energy efficiency and safety by reducing gas leaks and pollutant emissions, while optimizing existing processes through staged compression and adiabatic cooling.

Implementation Method 1

a compressor (1) capable of transmitting to the hot gases a pressure close to the partial saturation pressure of the water vapour

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a cold medium (3) on which a heat exchange takes place with the gases in order to recover the heat beyond the PCS

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

a secondary circuit comprising means for circulating a heat transfer fluid through said cold medium

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

a droplet separator (4) downstream of said cold medium

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Data Source

PatentEP3045698B1Device and method for recovering heat contained in combustion gases
Publication Date: 2018.11.14 SOIZE
  • EP3045698B1 patent drawingFigure 1

AI summary

The present invention relates to a method and device for recovering heat from combustion gases. The device comprises: a primary circuit through which the combustion gases circulate and comprising: a sealed, pressurized chamber (2) equipped with a compressor (1); - a cold medium (3) on which heat exchange with said gases takes place; - a valve-type control means (5) adapted to adjust and regulate the pressure drop created upstream; - a condensate collector (7); - an outlet (10) for the treated and dry combustion gases; and the device further comprises a secondary circuit comprising means for circulating a heat transfer fluid through said cold medium. The invention also relates to a method implemented by the claimed device.