Fuel Lance Syngas Injection Acute Angle Tip
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Solution Overview
Problem
Gas turbines with sequential combustion face challenges in injecting large volumetric flows of syngas due to differences in gross calorific value, density, and combustion characteristics compared to natural gas, requiring significant modifications to the fuel lance and combustion chamber to avoid flashback and ensure efficient combustion.
Innovation Solution
The fuel lance features first injection openings at the tip, oriented at an acute angle with the lance axis, allowing syngas to be injected into the hot gas flow, with the angle optimized based on hydrogen content to reduce residence time in the mixing zone and maintain the lance's outside dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the lance diameter is increased to accommodate larger syngas volumetric flows, then the flow capacity for syngas is improved, but the aerodynamics of the burner deteriorates and requires new construction of the combustion chamber and casing
Solution Approach 1:
The fuel lance is segmented into multiple injection openings distributed around the lance periphery instead of a single large opening. This segmentation allows the total flow capacity to be maintained while each individual opening maintains appropriate aerodynamic characteristics for stable combustion, avoiding the need to redesign the combustion chamber.
Solution Approach 2:
The injection openings are oriented at an acute angle relative to the lance axis rather than perpendicular to it. This angular orientation changes the dimensionality of the fuel jet injection, allowing the fuel to be injected in a direction that reduces residence time in the mixing zone and prevents flashback while maintaining flow capacity through the existing lance diameter.
2Reliability
If the residence time of syngas in the mixing zone is reduced to prevent flashback, then combustion stability is improved, but the injection geometry becomes more complex
Solution Approach 1:
The injection geometry is made dynamic by orienting the injection openings at an acute angle to the lance axis. This angular orientation causes the fuel jets to be injected in the direction of gas flow, dynamically reducing the residence time of syngas in the mixing zone and preventing flashback without requiring complex additional components.
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 configuration enables efficient use of syngas in gas turbines with minimal modifications, achieving maximum flow cross-section, minimized pressure drop, and reduced NOx emissions while preventing flashback, and allows for the use of syngas or natural gas with improved combustion behavior.
Implementation Method 1
the fuel jets which emerge from them form an acute angle with the lance axis. As a result of the displacement of the injection openings in the flow direction of the hot gas towards the tip of the lance, and as a result of the inclined position or tilting of the injected fuel jets in the flow direction, the residence time of the syngas in the mixing zone is reduced.
Data Source
AI summary
A fuel lance for a gas turbine installation with sequential combustion, in which hot gas is produced in a first combustion chamber and expanded in a subsequent turbine, and then flows through a subsequent second combustion chamber in which the fuel lance for injecting fuel into the hot gas is arranged. The fuel lance has a lance section which extends in the flow direction of the hot gas and includes at least an outer tube which is arranged concentrically to a lance axis, and a center tube which is concentrically arranged in the outer tube and in which the fuel is guided to the lance tip and is injected through first injection openings in the region of the lance tip into the hot gas. The fuel lance is modified for operation with syngas by the first injection openings being arranged directly on the lance tip, and by the first injection openings being oriented so that the fuel jets which emerge from them include an acute angle with the lance axis.