IGCC Condensate Heating Using Compressed Air to Cut Cooling Water

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Solution Overview

Problem

Integrated Gasification Combined-Cycle (IGCC) systems face challenges in water-constrained sites due to high cooling water and power consumption requirements, primarily in air separation units and steam condensing cycles, which are not optimally managed in existing systems.

Innovation Solution

The proposed solution involves coupling an air compressor with a condensate heater and an airfan condenser in IGCC systems, where a portion of compressed air is channeled to the condensate heater to reduce cooling water demand by preheating condensate and using airfan condensers to condense steam, thereby reducing the overall cooling water and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a larger cooling water duty is used to cool compressed air in multi-stage air compressors, then the compressed air temperature can be reduced to desired levels, but cooling water consumption increases beyond available amounts

Engineering Contradiction:

Improvecompressed air temperatureVSAvoidcooling water consumption

Core Design Contradiction:

TemperatureVSQuantity of substance

Solution Approach 1:

The system uses the compressed air itself to cool down after compression, eliminating the need for external cooling water. The compressed air is expanded through a turbine or expander, which naturally cools the air as it expands, and this cooled air is then reused in the gasification process, creating a self-sustaining cooling cycle.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the pressure parameter of the compressed air by expanding it through a turbine, which simultaneously changes the temperature parameter. This pressure-temperature transformation allows the hot compressed air to become cold enough for reuse without requiring cooling water.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If a larger cooling water duty is used in steam condensers to remove heat, then steam condensation efficiency improves, but cooling water consumption exceeds available amounts

Engineering Contradiction:

Improveheat removal efficiencyVSAvoidcooling water consumption

Core Design Contradiction:

Loss of energyVSQuantity of substance

Solution Approach 1:

The system merges the steam condensation function with the compressed air cooling function. The compressed air, which needs to be cooled, is used as the cooling medium for the steam condenser. This combines two cooling needs into a single integrated system that eliminates the requirement for separate cooling water supplies.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system uses its own compressed air to condense the steam, making the condensation process self-sufficient without external cooling water. The compressed air absorbs heat from the condensing steam and is subsequently cooled by expansion, creating a closed-loop thermal management system.

Inventive Principle:

Principle #25Self-service

3Temperature

If more cooling water is consumed in gasification systems, then cooling effectiveness improves, but water availability becomes insufficient at water-constrained sites

Engineering Contradiction:

Improvecooling effectivenessVSAvoidsuitability for water-constrained sites

Core Design Contradiction:

TemperatureVSAdaptability or versatility

Solution Approach 1:

The system replaces the water-based cooling mechanism with a mechanical expansion-based cooling mechanism. Instead of using water to absorb heat, the system uses the mechanical expansion of compressed air through a turbine to cool the air and condense steam, eliminating dependence on water resources.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 decreases cooling water requirements by up to 20% and reduces power consumption by utilizing steam generated from heated condensate to power system components, making IGCC systems more efficient and suitable for water-constrained sites.

Implementation Method 1

coupling a condensate heater in flow communication with the air compressor, and coupling a condenser in flow communication with the condensate heater. The condensate heater and the air compressor are coupled such that a portion of compressed air generated by the air compressor is channeled to the condensate heater

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the steam may be channeled through a steam condensing cycle that includes a condenser to transform water vapor into a liquid condensate

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

to remove a substantial amount of heat, known condensers may require a larger cooling water duty than is available

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS8186177B2Systems for reducing cooling water and power consumption in gasification systems and methods of assembling such systems

Publication Date: 2012.05.29 AIR PROD & CHEM INC

AI summary

An integrated gasification combined cycle system is provided. The integrated gasification combined cycle system includes an air compressor coupled in flow communication to an air separation unit, a condensate heater coupled in flow communication with the air compressor, and a condenser coupled in flow communication with the condensate heater. The condensate heater and the air compressor are coupled such that a portion of compressed air generated by the air compressor is channeled to the condensate heater. A method of assembling an integrated gasification combined cycle system is also provided.