Caustic Regeneration via Higee Oxidation and Catalyst
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for regenerating liquefied petroleum gas sweetening caustic fail to completely regenerate mercaptan sodium and sodium sulfide simultaneously, leading to the discharge of caustic sludge and reduced sweetening ability due to the presence of sodium sulfide and its oxidation products.
Innovation Solution
A method involving a sulfonated cobalt phthalocyanine-based catalyst and a Higee reactor, where the caustic undergoes an oxidation reaction with a high oxygen-to-caustic volume ratio, allowing for the complete regeneration of mercaptan sodium and sodium sulfide into sodium hydroxide, disulfide, and polysulfide, which are then separated and reused.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium sulfide is oxidized to sodium thiosulfate in the oxidation tower, then the oxidation reaction occurs, but the caustic cannot be completely regenerated and must be disposed as sludge
Solution Approach 1:
The invention changes the oxidation parameters by controlling the oxygen-to-caustic volume ratio to 1:5-10 and maintaining a specific temperature range (20-80°C), which alters the oxidation pathway to completely convert sodium sulfide to sodium hydroxide instead of stopping at sodium thiosulfate, achieving complete caustic regeneration
Solution Approach 2:
The invention uses a composite catalyst system comprising sulfonated cobalt phthalocyanine and manganese phthalocyanine, where the two catalysts work synergistically to enable complete oxidation of sodium sulfide to sodium hydroxide, overcoming the limitation of single-catalyst systems that only produce sodium thiosulfate
2Ease of manufacture
If a tower reactor is used for oxidation regeneration, then the process follows the classic Merox method, but mercaptan sodium and sodium sulfide cannot be completely regenerated simultaneously
Solution Approach 1:
The invention merges the oxidation of mercaptan sodium and sodium sulfide into a single oxidation tower process, using a composite catalyst system that simultaneously oxidizes both substances to their respective products (disulfide and sodium hydroxide), eliminating the need for separate treatment processes
Solution Approach 2:
The composite catalyst system acts as an intermediary that facilitates the complete oxidation of both mercaptan sodium and sodium sulfide. The sulfonated cobalt phthalocyanine and manganese phthalocyanine work together to enable reactions that would not occur efficiently with a single catalyst, achieving simultaneous complete regeneration
3Object-affected harmful factors
If pre-alkaline washing is performed to remove hydrogen sulfide, then residual hydrogen sulfide is removed, but sodium sulfide accumulates in the caustic and degrades sweetening ability
Solution Approach 1:
The invention converts the harmful sodium sulfide accumulation into a beneficial process by completely oxidizing it to sodium hydroxide in the oxidation tower. The sodium sulfide that would normally degrade sweetening ability is transformed into useful sodium hydroxide that can be reused in the extraction system, turning a waste product into a valuable resource
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 method achieves complete regeneration of liquefied petroleum gas sweetening caustic, reducing sodium thiosulfate accumulation and enabling the reuse of the caustic, with a simple process and low operational costs, effectively addressing the limitations of prior art.
Implementation Method 1
the caustic undergoes an oxidation reaction with a high oxygen-to-caustic volume ratio, allowing for the complete regeneration of mercaptan sodium and sodium sulfide into sodium hydroxide, disulfide, and polysulfide
Implementation Method 2
A method involving a sulfonated cobalt phthalocyanine-based catalyst and a Higee reactor, where the caustic undergoes an oxidation reaction
Implementation Method 3
the volume ratio of the liquefied petroleum gas sweetening caustic to an oxygen-containing gas is 1:10-500
Implementation Method 4
the resulting disulfide is insoluble in caustic and is separated from the caustic via gravity sedimentation in a disulfide sedimentation tank
Data Source
AI summary
A regeneration method for a liquefied gas thiol-removing alkaline solution comprising the following steps: performing an oxygenation reaction with respect to a liquefied gas thiol-removing alkaline solution and, at the same time, utilizing a high air-liquid condition to extract a disulfide and a polysulfide into a gas phase, thus completing the separation of the disulfide and the polysulfide from the alkaline solution, and implementing the regeneration of the liquefied gas thiol-removing alkaline solution.