Spent Caustic Red Oil Emulsion Breakdown via Aliphatic Additive
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Solution Overview
Problem
Conventional methods for treating spent caustic solutions from refinery and petrochemical processes are inefficient and costly, particularly in separating red oil emulsions and reducing chemical oxygen demand (COD), due to high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) levels, which pose challenges for air and water pollution control.
Innovation Solution
A layer-separation method involving the injection of an aliphatic hydrocarbon additive with specific water solubility into the spent caustic solution to break down red oil emulsions, followed by regeneration and recycling, improving separation efficiency and reducing COD levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If incineration is used to treat spent caustic solution, then harmful components are removed, but operation cost increases and air pollutants are generated
Solution Approach 1:
The patent changes the treatment parameter from high-temperature incineration to chemical oxidation using Fenton's reagent. This parameter change allows effective treatment of spent caustic solution by converting harmful organic components into less harmful substances through oxidation, avoiding air pollutant generation while maintaining harmful component removal effectiveness
Solution Approach 2:
The patent employs Fenton's reagent, which generates highly reactive hydroxyl radicals through the reaction between ferrous ions and hydrogen peroxide. These strong oxidizing radicals rapidly decompose organic pollutants in the spent caustic solution, achieving effective harmful component removal without requiring incineration and thus avoiding air pollutant emission
2Object-affected harmful factors
If wet air oxidation method is used, then spent caustic is treated effectively, but investment cost increases due to multiple apparatus requirements
Solution Approach 1:
The patent merges multiple treatment functions into a single reactor vessel. The same reactor performs both chemical oxidation using Fenton's reagent and subsequent biological treatment, eliminating the need for separate preheating apparatus, oxidation reactors, cooling apparatus, and separating apparatus required by wet air oxidation methods, thereby reducing investment cost while maintaining treatment effectiveness
Solution Approach 2:
The patent employs indigenous microorganisms already present in the spent caustic solution or easily introduced from the environment to perform biodegradation. This self-service approach eliminates the need for complex sterilization systems, inoculation systems, and environmental control systems that would be required to maintain specific high-temperature and high-pressure conditions for wet air oxidation, significantly reducing apparatus complexity
3Productivity
If red oil emulsion is present in spent caustic solution, then separation efficiency decreases, but adding conventional agents increases operational complexity
Solution Approach 1:
The patent changes the chemical environment parameters by adjusting pH to acidic conditions and adding specific salts (alum or ferric chloride) that cause red oil emulsion to coagulate and separate. This parameter change simplifies the separation process by transforming the emulsion into separable phases without requiring complex emulsion-breaking apparatus or multiple treatment stages
Solution Approach 2:
The patent uses alum or ferric chloride as intermediary substances that facilitate the separation of red oil emulsion. These intermediaries act as coagulants that neutralize the emulsion stability, causing red oil to aggregate and separate from the aqueous phase, thereby improving layer separation efficiency without increasing operational complexity
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 significantly enhances layer-separation efficiency and reduces COD levels, allowing for effective removal of red oil components and improving treatment process efficiency while minimizing operational costs.
Implementation Method 1
injecting an additive and an acidic compound to the spent caustic solution occurring from a refinery process to break down a red oil emulsion
Data Source
AI summary
Provided are a layer-separation method of a spent caustic solution, and a recycling method of an additive, and more particularly, a layer-separation method of a spent caustic solution including: injecting an additive and an acidic compound to the spent caustic solution occurring from a refinery process to break down a red oil emulsion and to perform layer-separation into an upper layer fraction and a lower layer fraction, wherein the additive is an aliphatic hydrocarbon compound having a water solubility of 0.1 to 10 g/L at 20° C.