Naphthalene Recovery From Rerun Column Bottom by Selective Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current industrial processes result in significant losses of naphthalene in waste streams, particularly the rerun column bottom, leading to economic and environmental burdens due to inefficient recovery methods.
Innovation Solution
A system and method involving an extraction unit, phase separation chamber, multi-stage extraction arrangement, evaporation unit, purification unit, drying and melting chamber, and cooling and crystallization unit to recover and purify naphthalene from rerun column bottom samples, achieving high purity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Gasoline Fractionator Overhead temperature is operated at approximately 105°C, then the process operates with current industrial parameters, but naphthalene content in the rerun column bottom increases to 9.3%-26.2%, causing significant material loss
Solution Approach 1:
The patent changes the operational parameter of the Gasoline Fractionator Overhead temperature from the conventional 105°C to a lower range of 85-95°C. This parameter change prevents naphthalene from entering the rerun column bottom stream, thereby eliminating the material loss while maintaining productive operation.
Solution Approach 2:
The patent converts the previously harmful effect of high overhead temperature (which caused naphthalene contamination and loss) into a beneficial outcome by operating at lower temperatures. This transforms the temperature parameter from a cause of loss into a control mechanism that prevents contamination and enables recovery.
2Manufacturing precision
If multi-stage extraction and purification processes are implemented to achieve high purity naphthalene recovery, then purity exceeds 97% and recovery efficiency reaches approximately 77.7%, but the device complexity and process steps increase
Solution Approach 1:
The patent segments the purification process into distinct stages: extraction stage (separating naphthalene from rerun column bottom), filtration stage (removing impurities), and crystallization stage (purifying the extracted naphthalene). Each stage uses simple, dedicated equipment, achieving high purity without requiring a single complex device.
Solution Approach 2:
The patent introduces an intermediary solvent (such as methanol or ethanol) to facilitate the extraction of naphthalene from the rerun column bottom stream. This intermediary enables selective separation and simplifies the overall purification process by transferring naphthalene to a different phase where it can be easily isolated and purified.
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 high-purity naphthalene recovery with a purity exceeding 97% and a recovery efficiency of approximately 77.7%, minimizing waste and enhancing resource utilization while being scalable and cost-effective.
Implementation Method 1
addition of a solvent such as methanol to the sample to form a mixture
Implementation Method 2
allowing the mixture to settle in a separation chamber for a period of time to achieve separation of a methanol-rich phase from a raffinate phase
Implementation Method 3
separating the methanol-rich phase from the raffinate phase with a separating funnel
Implementation Method 4
evaporation of the methanol-rich phase to obtain purified naphthalene crystals
Data Source
AI summary
A method for recovering high-purity naphthalene from a Rerun Column bottom residue is disclosed. The process begins with collecting the residue and dividing it into two portions. One portion is maintained at room temperature, while the second is cooled to approximately 16° C. to initiate the selective solidification of naphthalene. Upon gradual warming of the cooled portion to ambient temperature over 3-4 hours, a clear separation between solid naphthalene and the liquid residue is achieved. The liquid layer is decanted, and the remaining solid fraction is filtered using Whatman-1 filter paper with tissue paper to absorb residual liquids. The recovered crystals are washed 3-4 times with water to eliminate impurities and dried in a hot air oven at 100±2° C. for 2 hours. Final settling at room temperature yields dry, white crystalline naphthalene with a melting point of 80.2° C., a purity of 97.27%, and a recovery efficiency of 77.7%.