Hydrated Sorbent Aluminosilicate Chemisorption Corrosion
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Solution Overview
Problem
Thermal process plants face challenges with corrosion and emissions due to the presence of combustion-critical elements like chlorine, sulfur, and metals, which lead to high-temperature corrosion, slagging, and contamination, as well as disposal issues with ash quality, particularly in heat exchangers and exhaust gas systems.
Innovation Solution
A hydrated sorbent with basic character geopolymers and reactive oxide mixtures is added to the combustion process, utilizing aluminosilic chemisorption to bind problematic substances into an insoluble matrix, preventing further reaction and reducing corrosion and emissions by integrating them into the geopolymeric or hydrated hydraulic phases before they reach the exhaust path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional sorbents like bentonite or ammonium sulfate are used to prevent corrosion, then high-temperature corrosion is reduced, but acid dew point increases and soluble solids in ash increase, deteriorating disposal quality
Solution Approach 1:
The patent changes the chemical parameters of the sorbent by using hydrated basic character materials (geopolymers, hydrated hydraulic phases, sedimentites) with specific molar ratios of alumina to silicon oxide (≥0.13), replacing conventional acidic or neutral sorbents. This parameter change allows the sorbent to bind chlorine and sulfur compounds while maintaining basic character, preventing the formation of acidic condensates that would increase soluble solids in ash and improve disposal quality.
Solution Approach 2:
The patent employs composite hydrated sorbents comprising geopolymers, hydrated hydraulic phases, and/or sedimentites with basic character. These composite materials combine multiple functional components that work synergistically to bind combustion-critical elements while maintaining structural stability and basic character, thereby reducing both corrosion and soluble solids in ash simultaneously.
2Object-affected harmful factors
If sulfur compounds are injected to bind chlorine and sulfur, then corrosive substances are fixed, but acid dew point rises and total salt formers increase, leading to increased corrosion and contamination risk
Solution Approach 1:
Instead of using acidic or neutral sorbents that convert chlorine and sulfur into acidic compounds (increasing acid dew point), the patent inverts the approach by using basic character sorbents. These basic sorbents bind the same corrosive substances but convert them into stable, non-acidic compounds, thereby fixing corrosive substances while preventing acid dew point elevation.
3Quantity of substance
If hydrated basic character sorbents with alumina:silicon oxide ratio ≥0.13 are used, then soluble solids in ash are reduced and disposal quality improves, but the sorbent must be thermally activated to overcome strong chemical binding of hydrate water
Solution Approach 1:
The patent applies preliminary thermal activation to the hydrated basic character sorbents before injection into the combustion process. This preliminary action removes or weakens the strong chemical binding of hydrate water in the layered framework, activating the sorbent's porosity and reactivity. This ensures the sorbent is ready to effectively bind combustion-critical elements upon injection, overcoming the initial thermal barrier.
4Object-affected harmful factors
If the sorbent is injected into the combustion chamber, then corrosion and emissions are reduced, but residence time and temperature conditions must be optimized to ensure complete reaction and binding
Solution Approach 1:
The hydrated basic character sorbents with alumina:silicon oxide ratio ≥0.13 possess multi-functionality, enabling them to bind multiple combustion-critical elements (chlorine, sulfur, heavy metals) simultaneously under a wide range of combustion conditions. This universal binding capability reduces the need for precise optimization of residence time and temperature, as the sorbent remains effective across varying process parameters.
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 method effectively reduces high-temperature corrosion, fouling, and disposal issues by permanently integrating corrosive substances into an inert matrix, enhancing the stability of plant components and ash quality, and potentially eliminating the need for downstream exhaust gas purification.
Implementation Method 1
utilizing aluminosilic chemisorption to bind problematic substances into an insoluble matrix
Implementation Method 2
strong chemical binding of hydrate water in the layered framework
Data Source
AI summary
The invention relates to a method for limiting corrosion and emissions in thermal process plants by incorporating problematic substances released during combustion, such as chlorine, chlorine compounds, and heavy metals. It is characterized in that a hydrated sorbent with a basic character is added during combustion or before it reaches the exhaust gas path. Following the addition of the hydrated sorbent to the combustion process, chemically bound water and/or hydroxide groups and/or hydronium ions are released, forming reactive oxide mixtures. These reactive oxide mixtures can then be used to bind problematic substances, such as chlorides and heavy metals, into the aluminosilicate matrix via aluminosilicate chemisorption.This reduces and prevents slagging, bed agglomeration, soiling and caking, as well as alkali and chlorine bursting on the refractory lining, high-temperature corrosion and fouling on the heat exchanger surfaces and other plant components, and improves the relevant ash qualities for disposal purposes. A further advantage of the invention is that the downstream exhaust gas cleaning system can be designed to be smaller or even eliminated entirely.