Aromatic Extraction Unit
Aromatic extraction is currently the most important method for separating aromatic and non-aromatic hydrocarbons in the chemical industry. It is mainly used to separate and produce high-purity BTX aromatic products from gasoline fractions such as reformed oil and cracked hydrogenated gasoline. The technological aspect includes raw material fractionation part, aromatics extraction part, aromatics separation part and public works part.
The aromatic hydrocarbon extraction technology includes two different processes: liquid-liquid extraction and extractive distillation. The liquid-liquid extraction process is based on the difference of the solvent’s ability to dissolve aromatic and non-aromatic components. Extractive distillation process realizes rectification separation by selecting appropriate solvent and changing the relative volatility of non-aromatic and aromatic components. The products of aromatics extraction include raffinate oil, toluene products, C8+ reformed oil, etc.
The liquid-liquid extraction process can be divided into Udex method, sulfolane method (Sulfolane), N-methylpyrrolidone method (Arosolvan), dimethyl sulfoxide method (DMSO) and N-formyl morpholine according to the different solvents used. The most widely used method is the Sulfolane method.
The extractive distillation process includes morphylane process and sulfolane extractive distillation process. Relatively speaking, sulfolane extractive distillation process is more widely used. The extractive distillation process has the characteristics of short process, simple operation, low investment and small land occupation. Therefore, the new aromatic hydrocarbon extraction devices in recent years mostly adopt the extractive distillation process.