Sorbent Utilization via Ash Recirculation in Particulate Collectors
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Solution Overview
Problem
Electric generating units (EGUs) face high costs due to the excessive use of sorbents for pollutant control, necessitating a reduction in sorbent quantity while maintaining effective pollutant capture to comply with stringent regulations such as the Mercury and Air Toxic Standards.
Innovation Solution
A system for particulate emission removal from EGUs involves a gas producer, a primary particulate collector unit, and a particulate recirculation duct that reinjects ash-sorbent mixtures back into the flue gas to enhance pollutant capture, reducing the need for fresh sorbent usage by up to 30%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sorbents are injected into flue gas for pollutant control, then pollutant capture effectiveness is improved, but sorbent consumption and operational cost increase
Solution Approach 1:
The patent recovers spent sorbent from the particulate collector and reinjects it upstream of the collector, creating a circulation loop that extends sorbent utilization. This recovery approach reduces fresh sorbent consumption while maintaining pollutant capture effectiveness, directly addressing the contradiction between reliability and quantity of substance.
Solution Approach 2:
By continuously recirculating spent sorbent back into the flue gas stream, the system maintains continuous useful action from the sorbent. The sorbent performs multiple cycles of pollutant capture before being permanently discarded, extending its operational lifespan and reducing overall consumption while sustaining effective pollutant control.
2Quantity of substance
If sorbent quantity is reduced to lower operational cost, then expense is reduced, but pollutant control effectiveness may deteriorate
Solution Approach 1:
The recirculation system recovers spent sorbent that would otherwise be discarded and reuse it for additional pollutant capture cycles. This extends the effective service life of each unit of sorbent, allowing reduced fresh sorbent input while maintaining the same level of pollutant control effectiveness.
Solution Approach 2:
The system uses a portion of the collected particulate material (which contains spent sorbent) to serve as the recirculation medium, making the system self-sufficient in maintaining sorbent presence in the flue gas without requiring continuous fresh sorbent injection.
3Reliability
If fresh sorbent is continuously injected to maintain pollutant control, then emission standards are met, but operational expense increases
Solution Approach 1:
Instead of continuously injecting fresh sorbent, the system recovers and recirculates spent sorbent, reducing the need for continuous fresh sorbent purchase and injection while maintaining regulatory compliance through sustained pollutant capture effectiveness.
Solution Approach 2:
The continuous recirculation of spent sorbent maintains continuous useful action for pollutant capture, providing ongoing regulatory compliance without the continuous expense of fresh sorbent injection, as the recirculated sorbent continues to function across multiple cycles.
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 system achieves a 20-40% reduction in sorbent utilization, effectively capturing pollutants while minimizing costs and maintaining regulatory compliance, with the potential for further recycling of ash-sorbent mixtures in other industries.
Implementation Method 1
a primary particulate collector, the primary particulate collector comprising a dry electrostatic precipitator
Implementation Method 2
The injected sorbents may, in some instances, react with or adsorb targeted gas phase pollutants
Data Source
AI summary
Various embodiments of a system for the removal of particulate emissions from an electric generating unit are provided, comprising: a gas producer; a primary particulate collector unit including: a primary collection hopper field each including at least one primary collection hopper, wherein each primary collection hopper includes a primary collection hopper outlet, each primary collection hopper outlet fluidically connected to a particulate discharge duct; a flue duct inlet oriented upstream of the at least one primary collection hopper field; a flue duct outlet oriented downstream of the primary collection hopper field; wherein the gas producer is fluidically connected to the primary particulate collector unit by a flue duct; and a particulate recirculation duct fluidically connected at a first end to the primary collection hopper and/or the particulate discharge duct, and fluidically connected at a second end to the flue duct upstream of the primary particulate collector unit.