The production process of ordinary Solvent Naphtha is divided into two processes: cutting fractions and refining. Cutting is mainly to cut the light straight-run fraction (usually directly cut from the atmospheric tower) into appropriate narrow fractions or catalytic reforming raffinate for fractionation. All kinds of Solvent Naphtha generally need to be refined for the purpose of improving color, improving stability, reducing corrosive substances and reducing toxicity, etc. Refining methods mainly include alkali washing, white clay refining, hydrogenation refining and so on. In addition, ordinary solvent oil can also be produced by molecular sieve refining method. Products produced by these processes have relatively high sulfur and nitrogen content, and high content of aromatic hydrocarbons and unsaturated olefins, resulting in strong taste, strong toxicity, and dark color. Although they can meet the needs of solubility and economy, they are far from meeting special requirements. The needs of the occasion. After China’s accession to WTO, the quality standard of Solvent Naphtha products has been gradually improved, and the solvent oil for special occasions in my country is almost entirely dependent on imports.
Production process of high boiling point aromatic solvent oil. The domestic molding process includes the process flow of Yangzi Petrochemical Research Institute to produce high-boiling Solvent Naphtha with C10 heavy aromatics as raw materials. This process mainly considers the comprehensive utilization of by-products in the production process such as catalytic reforming of refineries and chemical plants to increase their added value. No. 1, 2, and 3 solvent oils and durene at 238°C.
Production process of low aromatics and dearomatized solvent oils. The solubility of ordinary Solvent Naphtha is not as good as aromatics, but aromatics are highly toxic and pollute the environment; high-boiling aromatic solvents are less volatile than ordinary solvents and have better solubility. They can replace the more toxic toluene and xylene, but they still have toxicity question. With the gradual enhancement of environmental protection awareness in various countries and the improvement of regulations on the use of solvent oil (especially the restrictions on volatile substances), low-toxic and non-toxic solvent oil has become the development direction of solvent oil manufacturers in various countries. There are four main solvent oil dearomatization technologies: hydrogenation method, which reduces the aromatics content in No. 6 Solvent Naphtha to less than 0.05%, and reduces the benzene content in straight-run gasoline to less than 0.02%; sulfonation method, petroleum solvent sulfonate Chemical-oxidation refining technology can reduce the content of aromatics in solvent oil to less than 0.1%; extractive distillation method uses N-methylpyrrolidone as the extraction agent, and the benzene content in No. 6 solvent oil can be reduced by extractive distillation. to less than 0.5%; adsorption method, molecular sieve adsorption dearomatization technology can reduce the aromatics content in No. 6 solvent oil to less than 0.01%, and the aromatics content of Solvent Naphtha No. 120 to less than 0.05%.
