Single-Substance Nozzles for Boiler Reducing Agent Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for injecting reducing agents into boilers of waste incineration plants, such as those using two-substance nozzles, are complex, large, and inefficient in reacting to temperature fluctuations, leading to suboptimal nitrogen oxide reduction with high agent consumption.
Innovation Solution
A method utilizing single-substance nozzles where the reducing agent and propellant are mixed before branching off to individual nozzles, allowing for stepless and quick adjustments based on temperature profiles, enabling precise injection of reducing agents like ammonia or urea at optimal temperatures for maximum nitrogen oxide reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-substance nozzles are used for injecting reducing agents, then the injection can be performed, but the device complexity and dimensions increase making installation difficult
Solution Approach 1:
The system separates the mixing function (in the distributor) from the injection function (in the nozzles). The distributor divides the reducing agent flow to multiple nozzles, while each nozzle only performs atomization and injection, simplifying its structure compared to integrated two-substance nozzles.
Solution Approach 2:
The distributor combines the reducing agent flow from the supply line and distributes it to multiple nozzles. This centralizes the flow control function, allowing simpler nozzle designs that focus only on injection rather than both mixing and injection.
2Adaptability or versatility
If two-substance nozzles with independent metering are used, then individual nozzle adjustment is possible, but the control response becomes sluggish and cannot react quickly to temperature changes
Solution Approach 1:
The distributor pre-divides the reducing agent flow to each nozzle line before injection. This preliminary distribution setup allows for pre-configured flow paths that can be quickly adjusted without the complex independent metering mechanisms of two-substance nozzles, enabling faster response to temperature changes.
Solution Approach 2:
The system uses a dynamic distribution ratio that can be adjusted based on real-time temperature measurements. The distributor can rapidly change the flow distribution to multiple nozzles in response to temperature fluctuations, providing both individual adjustability and fast response capability.
3Manufacturing precision
If ammonia is injected in highly diluted solution through two-substance nozzles, then even distribution is achieved, but the system requires complex central dilution infrastructure and has sluggish control
Solution Approach 1:
Instead of central dilution, the system performs local dilution at each nozzle by introducing air or steam directly at the injection point. This allows each nozzle to achieve proper mixing and distribution independently, eliminating the need for complex centralized dilution infrastructure while maintaining even distribution.
Solution Approach 2:
Air or steam acts as an intermediary substance introduced at the nozzle level to dilute and atomize the reducing agent. This intermediary approach enables local mixing and distribution without requiring extensive water supply infrastructure, simplifying the overall system while achieving even ammonia distribution.
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 approach allows for efficient and economical nitrogen oxide reduction with minimal agent consumption, effectively addressing temperature fluctuations and ensuring optimal operation by using structurally simple nozzles that can react to both local and temporal temperature changes.
Implementation Method 1
the substance to be injected and the propellant are brought together by the distributor before the respective line is branched off, so that a mixture containing the substance and the propellant is already present before the branch is made
Implementation Method 2
A method is disclosed in which single-substance nozzles are used, through which a mixture containing a substance and a propellant is conducted
Implementation Method 3
reducing agents in aqueous solution (e.g. ammonia water or urea) or gaseous (e.g. ammonia) are usually injected into the hot flue gases flowing through the boiler in order to reduce nitrogen oxides to molecular nitrogen according to the following equations. 4 NO + 4 NH 3 + O 2 -> 4 N 2 + 6 H 2 O 2 NO 2 + 4 NH 3 + O 2 -> 3 N 2 + 6 H 2 O
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for injecting a substance into a boiler (4) of a waste incineration plant using a gaseous propellant, wherein the substance is conveyed from at least one distributor (8) via lines (14a-i) branching off from the distributor (8) to a nozzle (16a-i) assigned to each line (14a-i), by means of which the substance and the propellant are injected into the boiler (4). The amount of substance to be conveyed to each nozzle (16a-i) is adjusted in the distributor (8). The method is characterized in that the substance and the propellant are combined before the branch of the respective line (14a-i).