Condenser Erosion Prevention in Low-Temperature Organic Rankine Cycle Systems

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Solution Overview

Problem

Existing systems for converting thermal energy from low-temperature sources into mechanical energy face challenges in preventing condenser erosion, which shortens the system's lifespan, while maintaining efficiency and avoiding increased complexity.

Innovation Solution

The method involves separating the liquid phase from the vapor phase immediately upstream of the condenser, allowing only the vapor phase to be condensed, and then recombining the phases before re-pumping, using a separator and a bypass line to direct the liquid phase past the condenser, thereby reducing erosion risk without significantly increasing system complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the two-phase mixture leaving the turbine is fed to the condenser, then the condensation process is complete, but liquid components cause erosion of the condenser, shortening its life

Engineering Contradiction:
Improvecondenser lifespanVSAvoidcondenser erosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The two-phase mixture flow is segmented into liquid phase and vapor phase using a separator. The liquid phase is separated and directed through a bypass line past the condenser, while only the vapor phase enters the condenser for condensation. This segmentation prevents liquid-induced erosion while maintaining complete condensation of the vapor phase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful liquid phase is extracted from the two-phase mixture before it enters the condenser. The separator extracts the liquid phase, which is then conducted past the condenser through a bypass line, eliminating the erosion problem while allowing the condenser to focus solely on condensing the vapor phase.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a separator and bypass line are added to prevent erosion, then condenser lifespan is extended, but system complexity increases

Engineering Contradiction:
Improvecondenser lifespanVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system is segmented into distinct flow paths: a main path through the condenser for vapor phase condensation, and a bypass path for the liquid phase. The separator divides the two-phase mixture into these two streams, allowing each component to follow its optimal path and preventing erosion without requiring complete system redesign.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separator acts as an intermediary device that mediates between the turbine outlet and the condenser. It separates the two-phase mixture into liquid and vapor phases, directing only the vapor phase to the condenser while bypassing the liquid phase, thus protecting the condenser without significantly complicating the overall system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the pressure in the condenser is optimized for minimal droplet size, then erosion is reduced, but mechanical energy generation decreases

Engineering Contradiction:
Improveerosion riskVSAvoidmechanical energy
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The liquid phase is separated from the vapor phase before the vapor phase enters the condenser. This preliminary separation action prevents liquid droplets from forming in the condenser entirely, eliminating erosion risk without requiring pressure optimization that would compromise mechanical energy generation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The presence of liquid phase in the two-phase mixture, which originally caused erosion harm, is converted into a benefit by separating it and directing it through the bypass line. This allows the condenser to operate at optimal pressure for maximum mechanical energy generation while the separated liquid phase bypasses the condenser, turning the potential harm into a protective measure.

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

This approach effectively prevents condenser erosion while maintaining significant efficiency advantages by optimizing the pressure in the condenser for minimal droplet size and maximal mechanical energy generation, ensuring the system's longevity and performance.

Implementation Method 1

a separator (7) for separating the liquid phase from the vapor phase of the expanded, partially vaporized working medium

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Implementation Method 2

Only the vapor phase is fed to the condenser (8) for condensation

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

the pressurized liquid working medium is heated in a heat exchanger by heat transfer from a low-temperature source

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

the heated, liquid working medium is expanded in a two-phase turbine, with partial evaporation of the working medium producing an expanded, partially vaporized working medium with a liquid and a vapor phase and thermal energy of the working medium being converted into mechanical energy

Methodology Applied
Scientific EffectAdiabatic expansion: Adiabatic Cooling

Implementation Method 5

The resulting water-steam jet is directed onto the turbine blades of the turbine, through which the kinetic energy of the water-steam jet is converted into mechanical energy of a rotor shaft

Methodology Applied
Scientific EffectTurbine work: Turbine

Implementation Method 6

The rotor shaft is in turn connected to a generator, which converts the mechanical energy of the rotor shaft into electrical energy

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2188499B1Method and device for converting thermal energy of a low temperature heat source into mechanical energy
Publication Date: 2016.09.28 KALINA POWER LTD
  • EP2188499B1 patent drawingFigure 1~2

AI summary

The invention relates a method and to a device (1) for converting thermal energy of a low temperature heat source (20) into mechanical energy in a closed circuit. The method consists of heating a liquid working agent by transmitting heat from the low temperature source (20) and partially evaporating it in an expansion device (3). According to the invention, erosion to the condenser (8) for condensing the partially evaporated working agent can be prevented by separating the liquid phase from the evaporator phase in the partially evaporated working agent that is directly in front of the condenser (8), and only the evaporator phase is transferred to the condenser (8) for condensing and subsequently, the condensed evaporator phase and the liquid phase are merged.