Staged Gas Injection System for Flare Tip Smokeless Combustion
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Solution Overview
Problem
Industrial flares face challenges in maintaining smokeless operation at low waste gas flow rates due to insufficient air entrainment, leading to increased steam usage and potential material degradation, with new regulations requiring consideration of steam consumption and potential for 'water hammer' issues.
Innovation Solution
A staged gas injection system with multiple gas injection assemblies that inject steam or alternative gases at varying flow rates and pressures to efficiently entrain air and maintain temperature, reducing steam consumption while preventing material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steam is injected at high flow rates to maintain smokeless combustion, then smokeless operation is achieved, but steam consumption increases and operational costs increase
Solution Approach 1:
The steam injection system is divided into multiple nozzles with different flow rate capabilities. The nozzle assembly includes at least two nozzles that can be selectively activated based on waste gas flow rate conditions, allowing efficient steam distribution across different operating scenarios
Solution Approach 2:
The system dynamically adapts steam injection by selecting appropriate nozzles based on real-time waste gas flow rate conditions. At high flow rates, high-capacity nozzles are used; at low flow rates, low-capacity nozzles are activated, optimizing steam consumption across the full operating range
2Quantity of substance
If steam flow rate is decreased to reduce operational costs, then steam consumption decreases, but air entrainment efficiency decreases and smokeless combustion cannot be maintained
Solution Approach 1:
The nozzle assembly segments steam injection capacity into multiple nozzles with different flow rates. This segmentation allows the system to maintain effective steam injection at low total flow rates by activating only the necessary number of nozzles, preserving smokeless combustion while reducing overall steam consumption
Solution Approach 2:
The system changes operational parameters by selecting different nozzle configurations based on waste gas flow rate. This parameter change allows the steam injection system to adapt its characteristics to match operating conditions, maintaining combustion quality across varying steam consumption levels
3Duration of action of stationary object
If continuous steam injection is maintained to prevent material degradation, then flare tip service life is extended, but operational costs increase due to minimum steam rate requirements
Solution Approach 1:
The system dynamically adjusts steam injection by activating different nozzle subsets based on operating conditions. This dynamic adaptation allows reduction of minimum steam rates during low-flow operations while still providing sufficient thermal protection to prevent material degradation, extending service life with lower steam consumption
4Reliability
If multiple steam lines with multiple sets of steam injection nozzles are used to improve smoke suppression, then smokeless operation is enhanced, but device complexity increases
Solution Approach 1:
Multiple nozzles are merged into a single integrated nozzle assembly that functions as one controllable unit. This merging approach provides enhanced smoke suppression through multiple injection points while avoiding the complexity of multiple independent steam lines, as all nozzles share common steam supply and control infrastructure
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 staged gas injection system enables efficient air entrainment and smokeless combustion at reduced steam usage, extending flare tip service life and reducing operational costs, while preventing material degradation and 'water hammer' issues.
Implementation Method 1
steam discharges from the steam nozzles at sonic velocity (Mach=1 or greater)... the steam pressure at the steam nozzles decreases and eventually the flow rate is decreased low enough so that the steam discharge velocity is less than sonic. As the steam velocity decreases, the efficiency with which the steam entrains air and mixes it with the waste gas stream decreases.
Implementation Method 2
The steam jets aspirate air from the surrounding atmosphere into the discharged waste gas with high levels of turbulence.
Implementation Method 3
The first gas injection assembly is configured to inject a gas at a high flow rate and a high pressure into the inner tubular member of the flare tip... The second gas injection assembly is configured to inject a gas at a low flow rate and a high pressure into the inner tubular member of the flare tip
Data Source
AI summary
A staged gas injection system for a flare tip that can discharge waste gas into a combustion zone is provided. The staged gas injection system includes, for example, a first gas injection assembly and a second stage gas injection assembly. The first gas injection assembly is configured to inject a gas (for example steam or a gas other than steam) at a high flow rate and a high pressure into the flare tip or the combustion zone. The second gas injection assembly is configured to inject a gas (for example, steam and/or a gas other than steam) at a low flow rate and a high pressure into the flare tip or the combustion zone. A flare tip including the staged gas injection system is also provided.