Flare Stack Diversion Control for Gas Plant Start-Up Flaring
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Solution Overview
Problem
Significant amounts of natural gas are flared during start-up or shutdown of gas plants due to off-spec gases, contributing to carbon emissions and violating environmental regulations.
Innovation Solution
Implementing a flare stack diversion system with a controller that senses off-spec gases during start-up and diverts the flow through a bypass path to a running train for additional treatment, ensuring the gas meets on-spec conditions before sale or distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If off-spec gases are flared during start-up to meet specification requirements, then gas quality is improved, but carbon emissions increase and environmental regulations are violated
Solution Approach 1:
The patent introduces a bypass flow-path as an intermediary route that allows off-spec gases to circumvent the flare stack and be redirected to a running train for additional treatment. This mediator enables the system to avoid direct flaring while still achieving specification compliance through alternative processing.
Solution Approach 2:
The patent converts the harmful effect of off-spec gases (which would normally require flaring) into a beneficial outcome by redirecting them to a running train for reprocessing. The previously harmful off-spec gases become treatable streams that can be converted into saleable products, thereby eliminating carbon emissions from flaring.
2Object-generated harmful factors
If a bypass flow-path is introduced to divert off-spec gases, then carbon emissions are reduced, but device complexity increases
Solution Approach 1:
The bypass flow-path and associated valves are designed to serve multiple functions: diverting off-spec gases during start-up, routing treated gases during normal operation, and providing flexibility for different operational scenarios. This multi-functionality justifies the added complexity by eliminating the need for separate dedicated systems.
Solution Approach 2:
The system employs dynamically controllable flow valves that can adjust their position based on real-time gas quality measurements and operational requirements. This dynamic control enables the system to adapt to varying conditions, optimizing the balance between gas quality, emissions reduction, and operational efficiency.
3Loss of substance
If off-spec gases are redirected to a running train for treatment, then saleable hydrocarbons are produced, but control system complexity increases
Solution Approach 1:
The control system continuously monitors gas quality parameters and uses this feedback to automatically adjust valve positions and routing decisions. This closed-loop control ensures that off-spec gases are consistently redirected for treatment while on-spec gases are routed directly to storage, maximizing hydrocarbon recovery with automated decision-making.
Solution Approach 2:
The system is designed to automatically manage the redirection and treatment of off-spec gases without requiring extensive manual intervention. The control logic autonomously determines when and where to route gases based on predefined criteria and real-time measurements, enabling the system to serve itself and reduce operational complexity.
Data Source
AI summary
A system for eliminating start-up flaring in a gas plant utilizing flare stack diversion logic comprises a natural gas source; a start-up train flow-path; a running train flow-path; a bypass flow-path; and a flare stack diversion controller, wherein the flare stack diversion controller is programmed to execute flare stack diversion logic comprising: detecting one or more natural gas feed parameters during start-up, receiving the one or more natural gas feed parameters, determining whether the one or more natural gas feed parameters fall outside pre-defined bounds, generating an alert or message to close the block valve, determining whether the block valve has been opened, closing a start-up train flow valve upon determining the block valve has been opened, and diverting all flow from the running train flow-path to the start-up train flow-path to eliminate start-up flaring of the natural gas feed.