Liquid Sulfur Degassing via Segregated Catalyst Bed
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Solution Overview
Problem
Existing methods for removing hydrogen sulfide and polysulfides from liquid sulfur face challenges such as catalyst attrition, corrosion, and slow reaction rates, particularly due to similar densities of sulfur and catalyst particles, and condensation of water and sulfur dioxide products leading to corrosion issues.
Innovation Solution
The use of a fixed catalyst bed with a trickle bed concept, where sulfur flows top to bottom across the bed, and an inert or low-oxygen stripping gas is employed, along with a separate decomposition and stripping section configuration to prevent catalyst attrition and optimize reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a decomposition catalyst is used in liquid sulfur treatment, then polysulfides are converted to hydrogen sulfide efficiently, but catalyst attrition occurs due to similar densities of sulfur and catalyst particles
Solution Approach 1:
The patent introduces a gas-liquid contactor as an intermediary device that facilitates the decomposition reaction between polysulfides and catalyst while preventing direct contact between catalyst particles and liquid sulfur flow. The contactor allows hydrogen sulfide to be stripped from the liquid phase into the gas phase, mediating the separation of catalyst from the bulk liquid and preventing catalyst attrition while maintaining decomposition efficiency
Solution Approach 2:
The treatment system is segmented into distinct functional zones: a decomposition zone where catalyst converts polysulfides to hydrogen sulfide, and a stripping zone where hydrogen sulfide is removed from the liquid. This segmentation prevents catalyst particles from being carried away by liquid flow while maintaining effective decomposition in the catalyst zone
2Productivity
If high-pressure oxidizing gas is used in counter current contact with liquid sulfur, then reaction rates increase, but water and sulfur dioxide condense leading to corrosion
Solution Approach 1:
The patent employs an inert or low-oxygen gas environment in the stripping zone to prevent oxidation reactions that would produce corrosive sulfur dioxide and water condensation. By using inert gas instead of high-pressure oxidizing gas, the system maintains high reaction rates through the catalyst while avoiding the formation of corrosive byproducts that would damage equipment
3Productivity
If sweep gas nozzles are used to expel hydrogen sulfide, then hydrogen sulfide removal is achieved, but the system requires large vessel volumes and complex recirculation systems
Solution Approach 1:
The patent merges the decomposition and hydrogen sulfide stripping functions into a single integrated gas-liquid contactor unit. The catalyst bed and gas-liquid contact zones are combined in one device, eliminating the need for separate recirculation systems and large vessel volumes while maintaining effective hydrogen sulfide removal through the integrated decomposition and stripping 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 effectively decomposes polysulfides to hydrogen sulfide and strips it from liquid sulfur with reduced catalyst attrition and corrosion, achieving high efficiency and low residual hydrogen sulfide levels, thereby improving the treatment process for liquid sulfur.
Implementation Method 1
contacting the liquid sulfur with a decomposition catalyst under conditions effective to convert polysulfides to hydrogen sulfide
Implementation Method 2
stripping the hydrogen sulfide enriched liquid sulfur stream with a stripping gas to so generate an acid gas stream and a liquid sulfur product stream
Data Source
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AI summary
Contemplated systems and methods for removing polysulfides and hydrogen sulfide from liquid sulfur of a Claus plant include (a) physically separated steps of catalytic decomposition of polysulfides and gas stripping, or (b) use of the stripping gas as the continuous phase in a packed column with decomposition catalyst to so avoid catalyst attrition.