Ammonia Injection Nozzle Position Adjustment for NOx Reduction

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Solution Overview

Problem

In burners with ammonia injection nozzles, there is a risk that insufficient ammonia supply to the flame reduction region can lead to increased nitrogen oxide (NOx) emissions in combustion gases, necessitating a solution to decrease NOx levels.

Innovation Solution

A combustion device with an ammonia injection nozzle and an adjustment structure that controls the separation distance between the injection port and the furnace inner space, using a control device to move the injection port closer to the furnace as the ammonia flow rate decreases, along with similar adjustments based on pulverized coal and air flow rates and furnace temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If ammonia flow rate is reduced, then CO2 emissions are decreased, but NOx emissions increase due to insufficient ammonia supply to the reduction region

Engineering Contradiction:

ImproveCO2 emissionsVSAvoidNOx emissions

Core Design Contradiction:

Loss of substanceVSObject-generated harmful factors

Solution Approach 1:

The injection port position of the ammonia injection nozzle is made dynamically adjustable rather than fixed. The adjustment structure changes the separation distance between the injection port and furnace inner space based on ammonia flow rate, allowing the system to adapt to varying operating conditions and maintain effective ammonia delivery to the reduction region even at lower flow rates

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the geometric parameter of the injection system by adjusting the separation distance between the injection port and furnace inner space. This parameter modification compensates for reduced ammonia flow rate, ensuring that ammonia is still effectively delivered to the flame reduction region where it is needed for NOx control

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the injection port is positioned farther from the furnace inner space, then fuel mixing is improved, but ammonia supply to the reduction region becomes insufficient

Engineering Contradiction:

Improvefuel mixingVSAvoidammonia supply to reduction region

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts the injection port position based on operating conditions. When ammonia flow rate decreases, the adjustment structure reduces the separation distance to ensure sufficient ammonia reaches the reduction region, while allowing greater distance when flow rate is high to maintain proper mixing

Inventive Principle:

Principle #15Dynamics

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 configuration ensures sufficient ammonia supply to the flame reduction region, effectively reducing NOx emissions across varying operation conditions.

Implementation Method 1

an ammonia injection nozzle having an injection port that faces an inner space of a furnace

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

an adjustment structure configured to adjust a separation distance between the injection port and the inner space

Methodology Applied

Scientific EffectMechanical displacement:

Data Source

PatentUS20230296244A1Combustion device and boiler

Publication Date: 2023.09.21 IHI CORP

AI summary

Provided is a combustion device including: a burner that includes an ammonia injection nozzle having an injection port that faces an inner space of a furnace; and an adjustment structure that adjusts a separation distance between the injection port and the inner space.