Methanol is used as solvent next to water (universal solvent) and as a raw material for the production of acetic acid, methyl tert-butyl ether, methyl acetate, motor spirit, vinyl acetate, acetic anhydride, formaldehyde, and styrene and these chemicals is used for the manufacture of adhesives, coating, photographic film, synthetic fiber, synthetic rubber and thermoplastic.
Methanol production technology:
- Destructive distillation of wood (it is no longer practiced)
- Non-catalytic oxidation of hydrocarbons (this process stopped in 1973)
- High-pressure process (in 1923 Mittasch and Schneider have discovered the process and later modified by the Hilberath and Peuckert)
- Medium pressure process
- Low-pressure process
Methanol production process description and flow diagram:
High-pressure process: From the Lurgi Corporation, UKW process produced methanol from synthesis gas (that has the composition of carbon monoxide and hydrogen). With help of advanced catalyst the production yield and conversion of the reaction was increased significantly. Most production plants have the capability of producing methanol with more 98% yield. The reaction is exothermic in nature and so based on the equilibrium constant the temperature of the reactor is maintained around 300 to 375 oC and pressure around 200 to 350 atm is required.
As per the flow sheet synthesis gas is compressed and preheated to the required temperatures of the reactor and fed to the reactor bottom, excess heat is recovered by the steam generators. Outlet gas is let downed to the 14 atm toward the depressurizing drum. The reactor used for this reaction is constructed with copper lined steel containing a catalyst which is blended with zinc, manganese oxide and chromium. The depressurized methanol will be in liquid state and it is treated with permanganate to remove impurities obtained during the side reaction on the catalyst surface. Mostly lower molecular weight dimethyl ether is obtained from the stripper top outlet and bottom high molecular weight methanol is obtained for storage and transport. A final purification step is carried out at methanol tower to remove water from methanol(CH3OH) because it is high solubility in water.
|Property of Methanol
Liquid density(25°c, 1atm)
Heat of fusion at mp
Triple point temperature
Triple point pressure
Fischer Tropsch Synthesis on Fe-based Catalysts
Formation of methanol chance is more in first elementary reaction step of Fischer Tropsch Synthesis when Fe-based catalyst is used for the synthesis gas conversion.
Due to complex polymerization reaction, different product likes paraffins, olefins, alcohols, etc. are formed while synthesis of hydrocarbons via the catalytic hydrogenation of carbon monoxide. A wide range of termination steps governs the particular product formation. At each reaction step individual products are formed for same raw material by Fischer Tropsch Synthesis, only thing to get the required product we need to control or stop the process at reaction with variables like reaction temperature, pressure, space velocity, selectivity etc. Obviously to achieve high chemical conversion, high selectivity of the reaction process should be designed for methanol production.
Organic product which include oxygen in their compound structure, are complex to obtain in Fischer Tropsch Synthesis when the catalyst is promoted with copper metal and alumina