Waste Liquid Oxidation Sequence for Sulfide Removal Without H2S
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Solution Overview
Problem
Existing methods for treating waste liquids with high concentrations of sulfide and organic composition, such as those used in the petrochemical and oil refinery industries, are costly, require high temperatures and pressures, and often produce harmful hydrogen sulfide gas, posing environmental and health risks.
Innovation Solution
A method involving precursory and advanced oxidative treatments using hydrogen peroxide, sodium percarbonate, and UV illumination, along with sodium or potassium persulfate, to stabilize and degrade sulfides and organic pollutants without generating hydrogen sulfide, utilizing a system with a reaction tank, photoactivation unit, and aeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet air oxidation method is used to treat waste liquid containing sulfide and organic composition, then sulfide and organic composition can be oxidized, but high temperature and high pressure conditions are required which increase equipment cost and operational difficulty
Solution Approach 1:
The patent changes the operating parameters from high temperature and high pressure to atmospheric pressure and moderate temperature (25-70°C). It introduces precursory oxidants (hydrogen peroxide, sodium percarbonate) and advanced oxidants (sodium persulfate, potassium persulfate) to enable oxidation under milder conditions, thereby reducing equipment material requirements and operational complexity while maintaining removal efficiency
Solution Approach 2:
The patent uses precursory oxidants and advanced oxidants as intermediary substances to facilitate the oxidation of sulfide and organic composition. These oxidants act as mediators that enable the oxidation process to proceed under atmospheric pressure and moderate temperature conditions, avoiding the need for high temperature and high pressure equipment
2Reliability
If traditional sulfur removal method is used, then sulfide can be removed, but hydrogen sulfide acid gas is generated which is toxic and corrosive
Solution Approach 1:
The patent converts the harmful oxidation process into a beneficial one by using precursory oxidants and advanced oxidants to oxidize sulfide directly to sulfate under controlled conditions. This approach eliminates the generation of hydrogen sulfide acid gas while maintaining effective sulfide removal, transforming a harmful process into a safe and beneficial treatment method
Solution Approach 2:
The patent creates an inert oxidation environment by introducing oxygen-containing gas (air or oxygen) during the oxidation process. This inert atmosphere prevents the generation of hydrogen sulfide acid gas while facilitating the oxidation of sulfide to sulfate, thereby eliminating the harmful byproduct
3Reliability
If high concentration of sulfide and organic composition is present in waste liquid, then treatment effectiveness is reduced, but the waste liquid requires intensive treatment
Solution Approach 1:
The patent segments the treatment process into three distinct stages: (A) precursory oxidation with hydrogen peroxide or sodium percarbonate to stabilize and convert sulfide, (B) advanced oxidation with sodium persulfate or potassium persulfate to degrade organic composition, and (C) UV illumination to activate oxidants and enhance degradation. This segmentation allows each stage to target specific contaminants efficiently, maintaining treatment effectiveness even at high concentrations
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
The method achieves complete sulfide conversion to sulfate and significant organic pollutant degradation, ensuring zero hydrogen sulfide gas generation, with high efficiency and cost-effectiveness, suitable for direct discharge or recycling as regenerative lye.
Implementation Method 1
adding a precursory oxidant or the precursory oxidant accompanied by aerating with oxygen-containing gas to a waste liquid containing a high concentration of sulfide and COD... the precursory oxidant is hydrogen peroxide or sodium percarbonate
Implementation Method 2
using UV illumination method to illuminate the oxidant dissolved in the waste liquid after the above step (B) or UV light to illuminate together with the residual hydrogen peroxide and/or sodium percarbonate in the waste liquid of the above step (A), the oxidant dissolved in the waste liquid is activated
Implementation Method 3
aerating with oxygen-containing gas
Data Source
AI summary
A method for treating a waste liquid comprises: step (A), adding a precursory oxidant to a waste liquid having a temperature of 25-70° C.; wherein, the precursory oxidant is hydrogen peroxide or sodium percarbonate, and in mg/L, a ratio of the precursory oxidant/the total amount of sulfide is 2.20 to 6.37; step (B), mixing an advanced oxidant and the waste liquid after step (A); wherein, the advanced oxidant is sodium persulfate or potassium persulfate, and in mg/L, a ratio of the advanced oxidant/COD after step (A) is 7.63 to 33.27; step (C), using UV illumination method to illuminate the oxidant dissolved in the waste liquid after step (B), and aerated with oxygen-containing gas. By the above-described method, it can achieve the purpose of sulfide conversion and degradation and removal of organic pollution composition under the condition free of the generation of H2S.