Sodium Sulfide Purification via Organic Solvent Phase Separation
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Solution Overview
Problem
Current methods for separating and purifying sodium sulfide by-products from petroleum desulfurization processes face challenges such as incomplete oil recovery, contamination, and the need for complex multistep solvent processes, leading to inefficiencies and increased costs.
Innovation Solution
A method involving the use of a mixture of organic solvents like xylene and water to separate and purify sodium sulfide, where the sludge is treated to form distinct phases, allowing for distillation and recovery of both the organic phase containing petroleum oil and the aqueous phase containing sodium sulfide, followed by oxidation to produce sodium sulfite without catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is added directly to separate sodium sulfide from sludge, then separation is attempted, but incomplete dissolution occurs due to water-impenetrable coating of residual feed oil, forming non-separable emulsion
Solution Approach 1:
The patent applies preliminary action by adding organic solvent to the sludge before adding water. The organic solvent first dissolves the residual feed oil coating on the sodium sulfide particles, removing the water-impenetrable barrier. Only after this preliminary treatment does water get added to dissolve the sodium sulfide, ensuring complete and effective separation without emulsion formation.
2Loss of substance
If multistep solvent process is used to recover oil from by-product sludge, then oil recovery is achieved, but large quantities of organic solvent are required, increasing cost and complexity
Solution Approach 1:
The patent merges the oil recovery step with the sodium sulfide separation step into a single integrated process. The organic solvent is added once to the sludge, simultaneously achieving both oil dissolution/recovery and preparation for sodium sulfide separation. This eliminates the need for separate multistep solvent processes, reducing both solvent consumption and process complexity while maintaining effective oil recovery.
3Quantity of substance
If organic solvent extraction is used to separate petroleum oil from sodium sulfide, then oil separation is achieved, but substantial quantity of feed oil remains associated with sodium sulfide by-product
Solution Approach 1:
The patent applies parameter changes by controlling the temperature, solvent-to-sludge ratio, and mixing conditions during the organic solvent extraction process. By optimizing these parameters, the extraction efficiency is maximized, ensuring that petroleum oil is thoroughly separated from the sodium sulfide by-product. The enhanced parameters enable complete dissolution of residual oil, achieving high separation purity with minimal oil association in the final sodium sulfide product.
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 enables efficient separation and purification of sodium sulfide, reducing solvent usage and costs, and facilitates the conversion to higher-value sodium sulfite, improving process simplicity and yield.
Implementation Method 1
treating a sludge containing Na2S by-product obtained during desulfurization of petroleum residue with a mixture of at least one organic solvent capable of dissolving the petroleum residue and water
Implementation Method 2
allowing the treated sludge to separate into an organic phase containing petroleum oil and an aqueous phase containing Na2S
Implementation Method 3
distilling the aqueous phase to obtain isolated Na2S followed by purification
Implementation Method 4
facilitates the conversion to higher-value sodium sulfite
Data Source
AI summary
The present disclosure provides a method for isolation and purification of sodium sulfide (Na2S) formed during desulfurization of petroleum residue. The process involves treating a sludge containing Na2S obtained during desulfurization of petroleum residue with a mixture of at least one organic solvent and water.