Venturi Condensate Recirculation for Acid Dew Point Corrosion

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Solution Overview

Problem

In combined cycle power plants, maintaining an adequate temperature at the exhaust end of the heat recovery steam generator to prevent acid gas dew point corrosion is challenging due to variations in fuel sulfur content, and existing condensate recirculation pumps require additional infrastructure and maintenance.

Innovation Solution

A condensate recirculation pump utilizing a venturi effect to recirculate flow medium from downstream of the condensate preheater system to upstream, maintaining a predetermined temperature by mixing it with condensate, thereby eliminating the need for additional infrastructure and reducing maintenance costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a motor driven condensate recirculation pump is used to maintain adequate temperature at the exhaust end of the heat recovery steam generator, then the temperature control is improved, but additional foundation interfaces, wiring, piping, and automatic recirculation valve are required increasing device complexity

Engineering Contradiction:

Improvetemperature at exhaust end of heat recovery steam generatorVSAvoidadditional foundation interfaces, wiring, piping, and automatic recirculation valve

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent extracts the motor drive components (foundation interfaces, wiring, automatic recirculation valve) from the condensate recirculation system by using a passive recirculation approach where condensate naturally circulates through the heat recovery steam generator exhaust end, eliminating the need for motor driven pumps and associated infrastructure while maintaining temperature control

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the condensate recirculation function into separate zones: a first zone receiving condensate from the steam turbine and a second zone receiving flow medium from downstream of the condensate preheater, allowing independent temperature management without requiring a single complex motor driven pump system

Inventive Principle:

Principle #1Segmentation

2Temperature

If a motor driven condensate recirculation pump is used to maintain adequate temperature, then temperature control is improved, but maintenance requirements increase

Engineering Contradiction:

Improvetemperature at exhaust end of heat recovery steam generatorVSAvoidmaintenance requirements

Core Design Contradiction:

TemperatureVSEase of repair

Solution Approach 1:

The patent implements a self-service recirculation system where condensate automatically circulates through the heat recovery steam generator exhaust end using pressure differentials and thermal buoyancy forces, eliminating moving parts that require maintenance while maintaining adequate temperature control

Inventive Principle:

Principle #25Self-service

3Temperature

If additional infrastructure is added for motor driven condensate recirculation pump, then temperature control capability is improved, but construction costs increase

Engineering Contradiction:

Improvetemperature at exhaust end of heat recovery steam generatorVSAvoidconstruction costs

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent removes the need for motor driven pumps, automatic recirculation valves, and associated infrastructure by utilizing passive recirculation mechanisms, thereby eliminating construction costs related to these components while maintaining the ability to control temperature at the heat recovery steam generator exhaust end

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the condensate itself serve multiple functions: it cools the steam turbine, preheats in the condensate preheater, and recirculates to maintain temperature at the exhaust end, eliminating the need for separate dedicated infrastructure for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 venturi-based condensate recirculation pump effectively maintains the required temperature, reducing construction and maintenance costs while minimizing space requirements and eliminating the need for additional interfaces, wiring, and valves.

Implementation Method 1

The condensate recirculation pump comprises a suction zone formed by a venturi effect for the recirculation

Methodology Applied

Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentUS11041409B2Combined cycle power plant having condensate recirculation pump using venturi effect

Publication Date: 2021.06.22 SIEMENS ENERGY INC

AI summary

A combined cycle power plant and a method for operating a combined cycle power plant are presented. The combined cycle power plant includes a condensate recirculation pump to recirculate flow medium from downstream of a condensate preheater system to upstream of the condensate preheater system. An adequate flow temperature at the upstream of the condensate preheater system may be maintained to prevent acid gas dew point corrosion. The condensate recirculation pump may use a venturi effect to convert a high pressure of a condensate supplied by a condensate extraction pump to a suction pressure for the recirculation.