Spray Dryer Absorber Alkali-Free Granular Mediator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spray dryer absorbers used for reducing acid gases in flue gases face reliability issues due to cementing deposits and potential plugging of reagent distribution components, which can lead to incomplete drying and reduced operational reliability, especially when alkali-containing reagents are used.
Innovation Solution
Incorporating a low or no alkali-containing granular material, such as fly ash or sand, into the spray dryer absorber system to dilute the alkali-containing reagent and reduce the tendency for cementing, thereby improving reliability and allowing for a potential size reduction of the equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkali-containing reagents are used in spray dryer absorbers to remove acid gases, then SO2 removal efficiency is improved, but cementing deposits form on walls and reagent distribution components causing plugging and reduced reliability
Solution Approach 1:
The patent introduces an alkali-free or low-alkali granular material (such as fly ash or sand) as an intermediary substance. This material is co-injected with the alkali-containing reagent into the flue gas stream. The alkali-free granular material acts as a mediator that prevents direct contact between the alkali-containing reagent and the walls/reagent distribution components, thereby preventing cementing deposits while maintaining SO2 removal efficiency through the alkaline reaction with acid gases.
2Productivity
If alkali-containing reagents are sprayed into hot flue gas to cool and absorb SO2, then acid gas removal efficiency is improved, but the reagent distribution components are prone to plugging
Solution Approach 1:
The alkali-free granular material serves as a protective intermediary that coats or separates the reagent distribution components from the alkali-containing reagent slurry. This prevents the reagent from adhering to and plugging the distribution nozzles and components, ensuring continuous operation and maintaining high SO2 removal efficiency without component failures.
3Productivity
If the spray dryer absorber is designed for complete drying of reagent droplets, then SO2 absorption efficiency is improved, but the equipment size increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the reagent system by introducing alkali-free granular material. This modification alters the drying characteristics and reaction kinetics, allowing the system to achieve effective SO2 absorption with reduced residence time and smaller equipment volume. The granular material provides additional surface area for reaction and modifies the droplet evaporation behavior, enabling compact design while maintaining absorption efficiency.
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 introduction of low or no alkali-containing particulate compounds enhances the mixing of reagents, reduces cementing, and improves the long-term reliability and compactness of spray dryer absorbers, enabling their use in spatially confined applications and retrofitting existing units.
Implementation Method 1
spray drying chemical absorption process, also known as dry scrubbing, wherein an aqueous alkaline solution or slurry is finely atomized and sprayed into the hot flue gas to remove the contaminants
Implementation Method 2
drying alkaline reagent slurry atomized into fine droplets in the hot flue gas stream
Implementation Method 3
absorption of SO2 and other acid gases from the gas stream. The process is also called semi-dry scrubbing to distinguish it from injection of a dry solid reagent into the flue gas
Data Source
AI summary
A spray dryer absorber (SDA) system used to reduce the concentration of at least one acid compound in a gas utilizes low or no alkali-containing particulate compounds to prevent cementing during operation. The low or no-alkali-containing compounds may be supplied from external sources and/or from a particulate collection device located downstream of the SDA.