Feasibility Analysis of Oil Filtration in Methanol
Methanol feed because of containing oil (should be advanced alkanes, may be mixed with paraffin in the process of transportation, olefins and naphthenes diesel fuel components, also may be in the process of methanol production cannot be thoroughly remove the impurity in the thick alcohol), caused by industrial wastewater COD value is higher, increased the burden of wastewater treatment, whether by filtering the raw material of methanol to oil removal, The methanol can produce all kinds of impurities due to different production control conditions.
1. This kind of impurities can be identified by the potassium permanganate test. It is generally believed that the reductive substances that are easily oxidized are aldehydes, amines, and carbonyl iron.
2. The solubility of soluble impurities based on the physical properties of methanol impurities can be divided into three categories: water solubility, alcohol solubility and insoluble solubility in water and methanol solution.
(1) water-soluble impurities: ether, C1 ~ C5 alcohol, aldehydes, ketones, organic acids, amines, etc., have high solubility in water, and when the methanol solution is diluted, it will not be precipitated or cloudy.
(2) alcohol-soluble impurities: C6 ~ C15 alkanes, C6 ~ C16 alcohols. Such impurities are dissolved only in the high concentration of methanol, which is precipitated out of the solution when the concentration of methanol in the solution is reduced, or the solution becomes turbid (that is, water-insoluble).
(3) insoluble impurities: C16 and above alkanes and C10 alcohols, which are not soluble in methanol and water at normal temperature, will crystallize in the liquid or make the solution cloudy.
3. In addition to impurities formed in the synthesis reaction, inorganic impurities also have mechanical impurities and trace other impurities from the production system.
4. The conductivity of the electrolyte and water pure methanol is 4 x 107 Ω cm, due to the presence of water and electrolyte, the conductivity decreased. In crude methanol, electrolytes are mainly: organic acid, organic amine, ammonia and metal ions such as copper, zinc, aluminum, iron, sodium, etc., and trace amounts of sulfide and chloride. If the boiling point of methanol is bounded, organic impurities can be divided into high boiling point impurities and low boiling points Usually in the boiling point of methanol is bounded, the boiling point lower than that of methanol boiling point 64.7 ℃ components called light fraction, boiling point higher than 64.7 ℃ is called heavy distillate, methanol is referred to as the key components. Methanol distillation process, the part of the alcohol soluble impurities easily and methanol azeotrope formation, it is difficult to get rid of by ordinary distillation, therefore, of pure methanol if they contain dozens of PPM alcohol soluble impurities can cause unqualified water soluble.