Flash Vessel Deaeration via Gas-Liquid Contactor
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Solution Overview
Problem
Existing methods for removing dissolved oxygen from slag sump water in gasification systems are inefficient, costly, and prone to corrosion, as they often require vacuum flash vessels and additional deaeration equipment.
Innovation Solution
A low-pressure flash vessel with a gas-liquid contactor is used to deaerate the slag sump water by contacting it with flash gas produced from the gasifier blowdown, effectively removing dissolved oxygen using a single vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum flash vessels and additional deaeration equipment are used to remove dissolved oxygen from slag sump water, then deaeration effectiveness is improved, but equipment complexity and operational costs increase
Solution Approach 1:
The patent combines the flash vessel and deaeration functions into a single integrated unit. The flash vessel receives slag sump water and flash gas, and the gas-liquid contactor within the same vessel performs deaeration by stripping dissolved oxygen using the flash gas as stripping medium, eliminating the need for separate vacuum flash vessels and deaeration equipment.
Solution Approach 2:
The flash vessel is designed to perform multiple functions simultaneously: pressure reduction (flashing), gas-liquid contact, and deaeration. This multi-functional design allows the single vessel to replace what would traditionally require multiple specialized equipment pieces, reducing overall system complexity while maintaining deaeration effectiveness.
2Reliability
If traditional deaeration methods are used, then dissolved oxygen removal is achieved, but corrosion of downstream components occurs due to inefficient deaeration
Solution Approach 1:
The patent introduces flash gas as an intermediary stripping medium to remove dissolved oxygen from slag sump water. The flash gas, generated from the flash vessel's pressure reduction process, serves as the stripping agent that efficiently carries oxygen away from the liquid phase, preventing corrosion while maintaining high deaeration efficiency.
Solution Approach 2:
The patent utilizes pressure reduction as a key parameter change to enable efficient deaeration. By reducing pressure in the flash vessel, dissolved oxygen becomes less soluble and is readily stripped from the slag sump water by the flash gas, achieving both high efficiency and effective corrosion prevention.
3Reliability
If multiple vessels and equipment are used for deaeration, then thorough oxygen removal is achieved, but operational costs increase
Solution Approach 1:
The system uses its own flash gas, generated internally during the pressure reduction process, as the stripping medium for deaeration. This self-service approach eliminates the need for external deaeration equipment and associated operational costs, while still achieving thorough oxygen removal through the gas-liquid contactor.
Solution Approach 2:
The patent converts the flash gas, which would otherwise be a waste stream or require separate handling, into a useful stripping medium for deaeration. By utilizing this internally generated gas to remove dissolved oxygen, the system achieves thorough oxygen removal while reducing operational costs and energy consumption.
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 efficiently deaerates the slag sump water, reducing equipment and operational costs while preventing corrosion in downstream components, and allows for the reuse of deaerated water in the gasification system.
Implementation Method 1
the gas-liquid contactor is configured to contact the stream of slag sump water with the first flash gas to enable the first flash gas to deaerate the stream of slag sump water
Implementation Method 2
the flash vessel is configured to receive a liquid feed at a first inlet and the blackwater stream at a second inlet... wherein the flash vessel comprises a gas-liquid contactor configured to contact the liquid feed with a first flash gas
Data Source
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AI summary
The disclosed embodiments relate to systems for deaerating a stream of slag sump water produced by a gasifier. For example, in one embodiment, a system 10 includes a flash vessel having a first inlet configured to introduce a first fluid into the flash vessel, wherein the flash vessel is configured to flash the first fluid to produce a first flash gas, a second inlet configured to introduce a stream from slag sump into the flash vessel, wherein the stream from slag sump comprises a mixture of a gasification fine slag, dissolved oxygen (O2), and water. A gas-liquid contactor 124 in the flash vessel is configured to contact the stream from slag sump with the first flash gas to enable the first flash gas to deaerate the stream from slag sump. A first outlet of the vessel is configured to output an overhead discharge comprising the first flash gas and oxygen from the stream from slag sump.