Heat Shield Plate for SCR Reducing Agent Supply
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Solution Overview
Problem
The concentration distribution of ammonia in a denitration device's flue gas passage becomes non-uniform due to heat transfer from hot flue gas to the ammonia supply pipe, leading to reduced denitration performance of the SCR catalyst.
Innovation Solution
A reducing agent supply device with a heat shield plate positioned upstream of the header pipe and fixed at intervals along its length, reducing heat transfer and maintaining uniform ammonia concentration through the use of injection nozzles with varying diameters and thermal conductivity configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the header pipe extends in the flue gas passage to supply reducing agent, then the reducing agent can be distributed across the passage width, but heat from the flue gas causes temperature variation and non-uniform concentration distribution of the reducing agent
Solution Approach 1:
A heat shield plate is introduced as an intermediary component between the flue gas and the header pipe. The heat shield plate absorbs and blocks heat from the flue gas, preventing it from transferring to the reducing agent in the header pipe, thereby maintaining uniform reducing agent temperature and concentration distribution
Solution Approach 2:
The harmful heat transfer path is extracted and isolated by positioning the heat shield plate upstream of the header pipe. The heat shield plate is fixed to the header pipe at specific positions, creating a physical barrier that extracts heat from the flue gas flow before it can affect the reducing agent supply
2Quantity of substance
If multiple nozzles are arranged at intervals along the header pipe, then uniform reducing agent distribution is achieved, but downstream nozzles receive heated reducing agent with lower concentration
Solution Approach 1:
The heat shield plate serves as a protective intermediary that shields all nozzles along the header pipe from heat exposure. By positioning it upstream and fixing it at multiple positions, the heat shield ensures that reducing agent maintains consistent temperature and concentration from proximal to distal nozzles, guaranteeing reliable denitration performance
Solution Approach 2:
The heat shield plate is positioned upstream of the header pipe to preemptively block heat transfer before it can affect the reducing agent. This preliminary protective action prevents temperature variation and concentration non-uniformity before they can occur in the first place
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 solution ensures a uniform ammonia concentration distribution across the flue gas passage, thereby maintaining the denitration performance of the SCR catalyst by minimizing temperature variations and pressure losses.
Implementation Method 1
heat transferred from the flue gas to the header pipe directly or indirectly can be significantly reduced
Implementation Method 2
heat transferred to the reducing agent in the header pipe can be significantly reduced
Data Source
AI summary
A reducing agent supply device for supplying a reducing agent to a portion of a passage for a flue gas upstream of a SCR catalyst includes at least one header pipe extending in the passage and configured to allow the reducing agent to pass through; a plurality of injection nozzles disposed on the header pipe at intervals along an extension direction of the header pipe and configured to inject the reducing agent into the passage; a heat shield plate disposed on an upstream side of the header pipe with respect to a flow direction of the flue gas and having a longitudinal direction along the extension direction of the header pipe; and at least one fixing part contacting each of the heat shield plate and the header pipe and fixing the heat shield plate to the header pipe.