Diluent Nitrogen Saturation for IGCC Combustor Stability
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Solution Overview
Problem
In Integrated Gasification Combined Cycle (IGCC) plants, the addition of water vapor as a diluent in syngas leads to variations in heating value, affecting combustor performance and efficiency, and moisture lowers firing temperature, potentially outweighing benefits.
Innovation Solution
A method and apparatus that produce nitrogen process gas, saturate it with water vapor, and heat it using waste process heat and compressor extraction air to supply dry syngas to the combustor, maintaining a constant heating value and enhancing efficiency by using low-level process heat to pre-heat diluent nitrogen and steam turbine condensate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water vapor is added as diluent to syngas to improve mass flow through combustor, then mass flow is improved, but heating value varies and firing temperature decreases
Solution Approach 1:
The patent changes the physical state of nitrogen from dry gas to saturated vapor state by controlling water vapor content, and adjusts temperature parameters through heating processes. This allows nitrogen to serve as diluent while maintaining stable heating value and firing temperature, resolving the contradiction between mass flow improvement and temperature maintenance.
Solution Approach 2:
The patent introduces a saturator and heater system as intermediary equipment between nitrogen production and combustor. This intermediary system conditions the nitrogen by saturating it with water vapor and heating it to specific temperature ranges, enabling the nitrogen to function as an effective diluent that maintains both mass flow and firing temperature stability.
2Productivity
If water vapor is added as diluent to syngas, then mass flow is improved, but combustor efficiency decreases
Solution Approach 1:
The patent optimizes water vapor content parameters in nitrogen to achieve saturation point, and controls temperature parameters through heating. These parameter changes enable nitrogen to maintain stable heating value while improving mass flow, thereby enhancing combustor efficiency rather than decreasing it.
Solution Approach 2:
The patent utilizes waste process heat from the IGCC plant to heat and saturate nitrogen, making the system self-sufficient. The waste heat that would otherwise be unused is now utilized to condition the diluent nitrogen, improving overall plant efficiency while maintaining combustor performance.
3Quantity of substance
If nitrogen is saturated with water vapor to act as diluent, then diluent availability is improved, but heating value stability deteriorates
Solution Approach 1:
The patent precisely controls water vapor content parameters to achieve nitrogen saturation point, and adjusts temperature parameters through heating processes. These controlled parameter changes ensure that the saturated nitrogen maintains stable heating value while providing sufficient diluent quantity, resolving the contradiction between availability and stability.
4Loss of energy
If waste process heat is used to heat saturated nitrogen, then plant efficiency is improved, but heat recovery requirements increase
Solution Approach 1:
The patent designs the heat recovery system to serve multiple functions: heating saturated nitrogen to combustion temperature, preheating feedwater, and generating steam. This multi-functionality approach maximizes waste heat utilization while avoiding excessive system complexity, as a single integrated heat recovery system handles multiple energy recovery tasks.
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 maintains constant combustor firing temperature and efficiency, allows efficient burning of dry syngas, and increases IGCC plant efficiency by utilizing waste process heat effectively.
Implementation Method 1
saturating the NPG with the water vapor
Implementation Method 2
the HRSG is configured to heat the low pressure steam loop
Implementation Method 3
a heat exchanger configured to heat the NPG using waste process heat and extraction air from the compressor
Data Source
AI summary
In one aspect, an embodiment of the present disclosure provides an Integrated Gasification Combined Cycle (IGCC) apparatus. The apparatus includes a saturator configured to saturate NPG with water vapor, and a heat recovery steam generator (HRSG), a low pressure steam loop through the saturator, wherein the HRSG is configured to heat the low pressure steam loop. The apparatus further includes a compressor and a heat exchanger configured to heat the NPG using waste process heat and extraction air from the compressor, wherein the heated NPG thereby becomes diluent nitrogen.