Variable Exhaust Regulator Bypass for SCR Catalyst Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust gas treatment systems face challenges in maintaining catalyst activity and efficiency due to low operating temperatures in coal-burning boilers, leading to poisoning phenomena and reduced nitrogen oxide reduction efficiency, particularly when using high-sulfur coal or oil, as the catalysts are not effectively regenerated in situ without disrupting boiler operations or increasing pressure loss.
Innovation Solution
An exhaust gas treatment apparatus with a variable exhaust regulator that bypasses the heat exchanger to supply high temperature exhaust gas directly to the SCR device, allowing for temperature adjustment and uniform mixing with low temperature exhaust gas, thereby maintaining the catalyst within its active range and preventing poisoning, while minimizing pressure loss and thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaust gas temperature is increased to maintain catalyst active temperature range, then catalyst activity is improved, but thermal damage to apparatus and energy loss increase
Solution Approach 1:
The bypass damper enables dynamic control of exhaust gas flow, allowing the system to adjust the proportion of high-temperature exhaust gas entering the SCR device based on real-time temperature requirements for catalyst activation and poisoning prevention
Solution Approach 2:
The system changes the temperature parameter of exhaust gas by selectively mixing high-temperature exhaust gas from the bypass with lower-temperature exhaust gas, achieving the optimal temperature range for catalyst operation without excessive thermal exposure
2Reliability
If high temperature exhaust gas is supplied through bypass to regenerate catalyst, then catalyst regeneration is achieved, but pressure loss and thermal damage increase
Solution Approach 1:
The bypass damper allows partial introduction of high-temperature exhaust gas rather than complete bypass flow, achieving sufficient catalyst regeneration while minimizing pressure loss and thermal stress on the system
3Loss of energy
If exhaust gas temperature is maintained low for energy efficiency, then energy loss is reduced, but catalyst poisoning occurs and nitrogen oxide reduction efficiency decreases
Solution Approach 1:
The system dynamically adjusts the bypass damper position based on operating conditions, allowing the catalyst to maintain activity and prevent poisoning while minimizing the amount of high-temperature exhaust gas required, thus reducing overall energy loss
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 solution enhances the efficiency and lifespan of the denitrification catalyst by maintaining uniform temperature exposure, allowing for effective nitrogen oxide reduction and catalyst regeneration within the active temperature range, reducing emissions, and simplifying apparatus design and maintenance.
Implementation Method 1
a heat exchanger (120) disposed between the combustion equipment (10) and the main discharge passage (110)
Implementation Method 2
a denitrification catalyst (134) disposed within a chamber (132) of the nitrogen oxide decreasing device (130)
Implementation Method 3
high temperature exhaust gas supplied through a bypass can be uniformly mixed with exhaust gas flowing in a main discharge passage
Data Source
AI summary
There is provided an exhaust gas treatment apparatus. The exhaust gas treatment apparatus includes: a main discharge passage through which exhaust gas of combustion equipment is discharged; an heat exchanger between the combustion equipment and the main discharge passage; a nitrogen oxide decreasing device connected to the main discharge passage to decrease nitrogen oxides of exhaust gas; a bypass connected from the combustion equipment to the main discharge passage as a passage bypassing the heat exchanger to supply high temperature exhaust gas from the combustion equipment to the nitrogen oxide decreasing device; and a variable exhaust regulator disposed between the bypass and the main discharge passage to vary the amount of relatively high temperature exhaust gas flowing in the bypass and the amount of exhaust gas flowing in the main discharge passage in a correlated manner.