In-situ Fly Ash Disposal System with MVR and Dioxin Removal
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Solution Overview
Problem
Existing methods for disposing of waste incineration fly ash are energy-intensive, lead to secondary pollution, and fail to effectively recover chloride salts, with current technologies either transferring dioxins to activated carbon or not adequately solidifying heavy metals, and often require long-distance transportation, increasing costs and environmental risks.
Innovation Solution
A system and method for clean and low-carbon in-situ disposal of waste incineration fly ash, integrating a water washing system, mechanical vapor recompression (MVR) system, and dioxin removal system, coupled with a waste incineration power plant, utilizing heat exchange and heat pump systems to recover energy and reduce water consumption, and employing activated carbon for dioxin adsorption and high-temperature degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature melting and sintering are used to dispose of fly ash, then dioxins can be effectively degraded and heavy metals solidified, but energy consumption increases and secondary pollution from heavy metal volatilization occurs
Solution Approach 1:
The patent changes the temperature parameter from high-temperature (above 850°C) to low-temperature (200-350°C) thermal desorption, achieving effective dioxin removal while avoiding heavy metal volatilization and reducing energy consumption. This parameter optimization resolves the contradiction between treatment effectiveness and energy efficiency.
Solution Approach 2:
The patent converts the harmful substance (dioxins adsorbed on activated carbon) into a beneficial form by using the activated carbon as a carrier for low-temperature thermal desorption, enabling effective dioxin degradation at lower temperatures without causing heavy metal volatilization, thus transforming a potential harm into a beneficial treatment approach.
2Ease of manufacture
If cement solidification and chemical stabilization combined with sanitary landfill are used, then fly ash can be disposed, but dioxins are not disposed and heavy metal leaching risk increases
Solution Approach 1:
The patent extracts and removes dioxins from fly ash through low-temperature thermal desorption in the presence of activated carbon, separating the dioxin removal function from the heavy metal solidification function. This enables independent treatment of dioxins while maintaining heavy metal stability, resolving the contradiction between ease of disposal and treatment reliability.
3Ease of manufacture
If fly ash is transported to disposal sites far from incineration plants, then disposal can be performed, but transportation costs increase and secondary pollution from leakage occurs
Solution Approach 1:
The patent implements self-service by locating the disposal system at the incineration plant itself, enabling the plant to treat its own fly ash without external transportation. The system uses on-site activated carbon and low-temperature thermal desorption to process fly ash, eliminating transportation costs and leakage risks while maintaining effective dioxin removal and heavy metal solidification.
4Loss of substance
If water washing is used to remove chloride salts from fly ash, then resource recovery is possible, but energy consumption increases
Solution Approach 1:
The patent merges the water washing process for chloride salt removal with the low-temperature thermal desorption process for dioxin removal. The water washing step prepares the fly ash for subsequent thermal treatment, and the integrated process achieves both chloride salt recovery and dioxin removal in a coordinated sequence, reducing overall energy consumption compared to separate high-temperature processes.
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 significantly reduces energy and water consumption, effectively solidifies heavy metals and removes dioxins, recovers chloride salts, and minimizes transportation-related pollution, achieving a 30%-50% cost reduction in fly ash disposal while ensuring the treated ash meets resource utilization standards.
Implementation Method 1
fly ash can be washed with water to remove a large number of chloride salts
Implementation Method 2
sodium chloride and potassium chloride can be evaporated and crystallized for recovery
Implementation Method 3
sodium chloride and potassium chloride can be evaporated and crystallized for recovery
Implementation Method 4
heat exchange equipment is arranged in the flue for recovering heat energy from the flue gas
Implementation Method 5
a heat pump system...configured to provide heat to the drying and thermal desorption processes
Implementation Method 6
activated carbon...to adsorb these toxic and harmful substances
Implementation Method 7
decomposing dioxins through the heat generated by high-temperature combustion of coal powder
Data Source
AI summary
A system and method for clean and low-carbon in-situ disposal of waste incineration fly ash includes a waste incineration system and a fly ash disposal system. The fly ash disposal system includes a water washing system, an MVR system, and a dioxin removal system. The water washing system includes a water washing device and a press filtering device. The dioxin removal system includes a heating device, an activated carbon adsorption device, and a heat pump system. The MVR system includes a crystallizer, a heater, a vapor compressor, and other equipment. The waste incineration system is coupled with the fly ash disposal system nearby to achieve in-situ disposal of fly ash, avoiding the logistics cost and secondary pollution problems of long-distance transportation of fly ash, and greatly reducing energy and water resource consumption.