TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Processes: The pre-treatment with 200+x acidified oil comprises: according to the characteristic difference of different acidified oil materials, using different treating processes; feeding to-be-treated acidified oil at the bottom of pre-treating tower, pouring washing water from top of tower, directly heating material to 200 degrees C through steam, draining treated acidified oil from top the tower; and draining washing water from bottom of the tower, with residence time of acidified oil in tower as x, for 0.5-0.6 (preferably 1-3) hour. The esterification is at 180-250 degrees C under 20-50 kg/cm2 for 2-8 hours. The esterification without catalyst is at 180-250 degrees C, with optimal temperature control at 210-225 degrees C. The pressure of high-temperature and high-pressure esterification without catalyst is 20-50 kg/cm2; and the optimal pressure control range is 38-45 kg/cm2. The time of high-temperature and high-pressure esterification without catalyst is 2-8 hours; and optimal time control is 4-6 hours. The distilling with scraper thin film evaporator continuously involves vacuum degree of continuous distillation at 0.2-2 mmHg, input temperature of heat conducting oil at 220-270 degrees C, and feeding temperature of esterified crude methyl ester at 180-220 degrees C. The distilling with scraper thin film evaporator continuously has optimal vacuum degree control of 0.4-0.8 mmHg. The input temperature of heat conducting oil of continuous distillation is 220-270 degrees C; and the optimal input temperature control of heat conducting oil is 240-260 degrees C. The distilling with scraper thin film evaporator continuously involves general feeding temperature of continuously esterified crude methyl ester at 180-220 degrees C, and the optimal feeding temperature control of crude methyl ester at 190-220 degrees C. The discharging residue through short-range molecular distillation continuously involves vacuum degree of continuous residue discharge under 0.1-1 mmHg, general input temperature of heat conducting oil at 200-270 degrees C, and general feeding temperature of concentrated liquid at 170-230 degrees C; general vacuum degree of continuous residue discharge under 0.1-1 mmHg, and the optimal vacuum degree control under 0.2-0.6 mmHg. The general input temperature of heat conducting oil is 200-270 degrees C; and the optimal input temperature control range of heat conducting oil is 240-260 degrees C. The general feeding temperature of concentrated liquid is 170-230 degrees C; the optimal feeding temperature control of concentrated liquid is 185-215 degrees C. The alkali refining and de-acidification involves general concentration of liquid caustic soda in continuous alkali refining and de-acidification at 18-26 baume degrees , general temperature control range of continuous alkali refining and de-acidification at 60-90 degrees C, distilled fatty acid methyl ester delivered by variable-frequency constant-current gear pump, liquid caustic soda delivered by variable-frequency constant-current precise diaphragm metering pump, methyl ester and liquid caustic soda mixed in dynamic mixer well, and aged by delay aging tank, and separated in a butterfly centrifuge to de-foam; and alkali refined ester dried by continuous vacuum dehydration after washing with soft water to obtain biodiesel meeting national standard. The general concentration of liquid caustic soda in continuous alkali refining and de-acidification is 18-26 baume degrees ; and the optimal concentration control of liquid caustic soda is 18-22 baume degrees . The general temperature control of continuous alkali refining and de-acidification is 60-90 degrees C; and the optimal temperature control of alkali refining is 80-90 degrees C.