Spray Dryer Absorber for WFGD Liquid Waste Reduction
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Solution Overview
Problem
Current systems for reducing liquid waste from wet flue gas desulfurization (WFGD) units are ineffective in processing a wide range of liquid waste sources and struggle with high total suspended solids content, leading to challenges in managing and disposing of this waste.
Innovation Solution
A system that incorporates a drying unit connected to WFGD units, utilizing flue gases to reduce and control the volume of liquid waste through spray dryer absorber or evaporation processes, and a mixing device to manage particulate matter, allowing for the control of chemistry and physical properties of the waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional liquid treatment plants are used to treat WFGD liquid waste, then liquid discharge compliance can be achieved, but the system cannot process liquid waste with high total suspended solids content (above 0.01-5% by weight)
Solution Approach 1:
The patent applies parameter changes by utilizing flue gas temperature and composition as processing parameters in the spray dryer absorber. The flue gas parameters (temperature, moisture content, sulfur dioxide concentration) are controlled to achieve both drying of liquid waste and sulfur dioxide removal, enabling the system to handle high suspended solids content that traditional plants cannot process
Solution Approach 2:
The patent employs phase transitions through the spray dryer absorber process where liquid waste is atomized into droplets, water evaporates from the droplets, and the resulting particulate matter is captured. This phase change from liquid to vapor (water evaporation) and liquid to solid (particulate formation) enables effective processing of high suspended solids content
2Quantity of substance
If liquid waste volume is reduced through drying processes, then liquid discharge is minimized, but energy consumption increases due to evaporation requirements
Solution Approach 1:
The patent converts the harmful flue gas (which contains heat, moisture, and sulfur dioxide) into a beneficial drying medium. The flue gas that would otherwise be wasted or require expensive treatment is utilized to provide the evaporation energy needed for liquid waste reduction, thereby converting a harmful factor into a useful resource and reducing overall energy consumption
Solution Approach 2:
The system achieves self-service by using its own flue gas production to power the drying process. The combustion process that generates the waste flue gas also provides the thermal energy required for evaporating water from the liquid waste, creating a self-sustaining system that reduces external energy requirements
3Quantity of substance
If spray dryer absorber processes are used to reduce liquid waste, then liquid volume is minimized, but control of downstream air quality systems becomes more complex
Solution Approach 1:
The patent merges two separate functions into a single integrated process: liquid waste drying and sulfur dioxide removal. The spray dryer absorber simultaneously evaporates water from liquid waste droplets and absorbs sulfur dioxide from flue gas, eliminating the need for separate drying and air quality control systems and simplifying overall system complexity
Solution Approach 2:
The spray dryer absorber is designed as a multi-functional device that performs multiple roles: it acts as a drying unit for liquid waste reduction, a sulfur dioxide removal system, and a particulate matter control device. This universal functionality reduces the number of separate systems needed and simplifies downstream air quality control
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 system effectively reduces and mitigates liquid waste volume, enabling the management of waste with high suspended solids content and controlling downstream air quality, thereby improving environmental compliance and operational efficiency.
Implementation Method 1
utilizing flue gases to reduce and control the volume of liquid waste through spray dryer absorber or evaporation processes
Implementation Method 2
a mixing device to manage particulate matter, allowing for the control of chemistry and physical properties of the waste
Data Source
AI summary
The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for reducing and/or eliminating various liquid discharges from one or more emission control equipment devices (e.g., one or more wet flue gas desulfurization (WFGD) units). In another embodiment, the method and apparatus of the present invention is designed to reduce and/or eliminate the amount of liquid waste that is discharged from a WFGD unit by subjecting the WFGD liquid waste to one or more drying processes, one or more spray dryer (or spray dry) absorber processes, and/or one or more spray dryer (or spray dry) evaporation processes.