pH-Controlled Alkali Dosing for Flue Gas Desulfurization
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Solution Overview
Problem
Existing non-waste water flue gas treatment systems face challenges in maintaining optimal removal performance of acid gases due to fluctuations in boiler load and fuel changes, leading to excessive or deficient alkali usage and increased costs.
Innovation Solution
A system that includes pH meters and alkali supplying units to regulate the pH of desulfurization waste water, and chlorine ion measurement devices to optimize the molar ratio of alkaline agent to chlorine ions, ensuring efficient acid gas removal by adding alkaline agents in predetermined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a great amount of alkali is added to ensure sufficient acid gas removal performance, then the removal performance is improved, but the cost of alkali increases and the removal performance becomes excessive
Solution Approach 1:
The patent implements a feedback control system where the pH of desulfurization waste water is continuously monitored and measured. Based on the measured pH value, the control unit automatically adjusts the amount of alkali added to maintain the pH within a predetermined range (6-10), ensuring optimal acid gas removal performance while preventing excessive alkali consumption. This closed-loop feedback mechanism resolves the contradiction by dynamically matching alkali addition to actual process conditions rather than using fixed excessive amounts.
Solution Approach 2:
The patent changes the control parameter from fixed alkali dosage to dynamic pH-based control. By monitoring pH as a key parameter and adjusting alkali addition accordingly, the system optimizes the balance between removal performance and alkali consumption. The predetermined pH range (6-10) serves as the target parameter that ensures sufficient acid gas removal while minimizing unnecessary alkali usage.
2Quantity of substance
If a small amount of alkali is added to reduce cost, then the cost of alkali is reduced, but the removal performance of acid gas becomes deficient
Solution Approach 1:
The feedback control system prevents deficient removal performance by continuously monitoring pH and automatically increasing alkali addition when pH drops below the predetermined range. The control unit receives real-time pH data and adjusts alkali dosage to maintain optimal conditions, ensuring that cost reduction does not compromise removal performance. This dynamic adjustment eliminates the need for operator guesswork and ensures consistent performance.
Solution Approach 2:
The system performs self-adjustment of alkali dosage based on automatic pH measurement and control. The control unit autonomously determines the appropriate alkali addition amount without external intervention, ensuring that the minimum necessary alkali is always added to maintain removal performance. This self-service capability prevents both under-dosage (deficient performance) and over-dosage (excessive cost).
3Ease of operation
If the amount of alkali is not controlled, then the operation is simple, but the removal performance fluctuates with boiler load and fuel changes
Solution Approach 1:
The patent implements automatic feedback control that replaces manual operation with instrumented control. pH meters continuously measure the waste water pH, and the control unit automatically adjusts alkali addition based on these measurements. This eliminates the need for operators to manually adjust settings in response to boiler load or fuel changes, maintaining both operational simplicity and performance stability simultaneously. The system adapts automatically to varying conditions without requiring operator expertise or attention.
Solution Approach 2:
The patent replaces manual mechanical adjustment operations with automated instrumented control systems. pH measurement devices and automatic control units substitute for human operators who would otherwise need to monitor and adjust alkali dosage in response to changing conditions. This substitution maintains ease of operation (automatic control) while ensuring reliable performance stability through continuous monitoring and adjustment.
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 stabilizes acid gas removal performance, reduces alkali costs, and prevents component volatilization, maintaining system efficiency despite load and fuel changes.
Implementation Method 1
a spray drying device configured to spray waste water including desulfurization waste water discharged from the desulfurization device... configured to evaporate and dry the desulfurization waste water
Implementation Method 2
an alkaline agent functions as a collecting agent for an acid gas (hydrogen chloride and the like)... configured to remove a sulfur oxide contained in the boiler flue gas with a desulfurization absorbing liquid
Data Source
AI summary
An apparatus is disclosed including a desulfurization device which removes sulfur oxides contained in boiler flue gas, a spray drying device which sprays desulfurization waste water discharged from the desulfurization device and which dries the waste water by introducing a drying gas, a flue gas supplying line L13 which returns, to a main flue L11, flue gas obtained after the desulfurization waste water is evaporated and dried, an alkaline agent supplying unit which adds an alkaline agent to a desulfurization waste water line L21, and a pH meter which measures the pH in the desulfurization waste water at locations before and after the alkaline agent supplying unit in the desulfurization waste water line L21, wherein the alkaline agent is added in accordance with a measurement result of a measured pH to cause the desulfurization waste water added with the alkaline agent to have a pH fall within a predetermined pH.