Catalytic Partial Oxidation for Gas Turbine Fuel Preparation
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Solution Overview
Problem
Gas turbines face issues with using fuels containing high levels of hydrocarbons with two or more carbon atoms and olefins, which can lead to thermal cracking and variability in fuel composition, making them unsuitable for direct use as gas turbine fuel.
Innovation Solution
A method involving a hydrocarbon-containing feed stream being treated in a catalytic partial oxidation reactor with steam and oxygen to reduce hydrocarbon content, resulting in a product stream with reduced olefin and heavy hydrocarbon levels, suitable for use in gas turbine combustors, by controlling oxygen to carbon and water to carbon ratios and optimizing reaction temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydrocarbon-containing offgases with high olefin and heavy hydrocarbon content are used as gas turbine fuel, then fuel utilization is improved, but thermal cracking occurs causing carbon deposits and combustion instability
Solution Approach 1:
The patent applies preliminary action by treating the hydrocarbon-containing offgases with a catalytic partial oxidation process before introducing them into the gas turbine combustors. This pretreatment converts olefins and heavy hydrocarbons into more stable compounds, preventing thermal cracking and carbon deposit formation during combustion while enabling the utilization of previously unsuitable fuel sources
2Adaptability or versatility
If the hydrocarbon composition of feedstock varies over time, then fuel flexibility is improved, but combustion stability deteriorates
Solution Approach 1:
The patent employs parameter changes by controlling the oxidation process parameters (temperature, oxygen concentration, residence time) to transform variable feedstock compositions into a consistent product composition. The catalytic partial oxidation converts varying hydrocarbon mixtures into a standardized gas composition suitable for lean premix combustion, thereby maintaining combustion stability despite feedstock variability
3Reliability
If blending is used to reduce thermal cracking problems, then combustion reliability is improved, but the degree of blending limits fuel utilization
Solution Approach 1:
The patent converts the harmful high-olefin and heavy-hydrocarbon composition into a beneficial property through catalytic partial oxidation. The process transforms the very components that cause thermal cracking into stable combustion-compatible gases, eliminating the need for blending with natural gas while maintaining combustion reliability and maximizing utilization of the offgases
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 method effectively reduces hydrocarbon content to acceptable levels, mitigates thermal cracking, and stabilizes fuel composition, enabling the use of previously unsuitable fuels and maintaining consistent fuel quality despite variations in feedstock.
Implementation Method 1
a hydrocarbon containing feed stream is reacted with steam and oxygen in a catalytic partial oxidation reactor to reduce the heavy hydrocarbon content of such stream
Implementation Method 2
catalytic partial oxidation reactor to reduce the heavy hydrocarbon content
Implementation Method 3
hydrocarbons with two or more carbon atoms or a high olefin content that can thermally crack and produce carbon deposits
Implementation Method 4
The reactant mixture is reacted within the catalytic partial oxidation reactor so that a product stream is produced at a temperature of between about 600° C. and about 860° C.
Data Source
AI summary
Method of preparing and introducing fuel into the combustors of a gas turbine in which a hydrocarbon containing feed, oxygen and steam are introduced into a catalytic partial oxidation reactor to produce a product stream. The hydrocarbon containing feed contains no less than about 15 percent by volume on a dry basis of hydrocarbons with at least two carbon atoms and/or at least about 3 percent by volume of olefins. The reactant mixture formed of the hydrocarbon containing feed, oxygen and steam has an oxygen to carbon ratio of between about 0.08 and about 0.25 and a water to carbon ratio of between about 0.05 to about 0.5. The hydrocarbon containing feed is introduced into the reactor alone or with a steam at a temperature no greater than 600° C. and the product stream is produced at a temperature of between about 600° C. and 860° C. and contains less than about 0.5 percent of olefins and less than 10 percent of hydrocarbons with two or more carbon atoms on a dry basis. After cooling the product stream the product stream is introduced into the combustors of the gas turbine to form part or all of the fuel required to support combustion.