A kind of production technology of sodium benzoate
Toluene oxidation. 2200kg of toluene and 2.2kg of cobalt naphthenate were pumped into the oxidation tower and heated to 120°C through the jacket steam to make the toluene boil. Start the air compressor, compress
The air enters the toluene solution from the bottom of the tower through the buffer tank to undergo oxidation reaction. The reaction is an exothermic reaction, and the reaction temperature rises. By stopping the heating and switching the cooling water, the control
The temperature cannot exceed 170. A large amount of toluene vapor and water vapor produced by the reaction are discharged from the top of the tower, and then enter the water separator after condensation. The toluene does not return to the oxidation tower from the water separator.
Water comes out from the lower part of the divider. The water separator is covered with a tail gas discharge pipe, and the tail gas enters the active absorption tower through the discharge pipe to the buffer tank to absorb the toluene in it. Toluene at 170
The oxidation time is 12~16h, and the conversion rate of toluene can reach more than 70%.
Debenzene. The oxidizing liquid is put into the benzene removal kettle, heated to 100~110°C through the jacket steam under 0.08MPa vacuum, and the unreacted toluene is evaporated by means of compressed air bubbles.
After condensation, it enters the water separator for recycling.
Distilled. The benzoic acid after debenzene still contains impurities and organic pigments, which need to be distilled again. Put the feed liquid into the still, heat and control the feed liquid temperature to be 190, and the benzoic acid will
Steamed and entered into the distillation tower, the temperature at the top of the tower was controlled to be 160 °C, and the effluent was cooled by a jacket and entered into the neutralization kettle to obtain pure benzoic acid.
neutralize. After the benzoic acid enters the neutralization kettle, the pre-prepared soda ash solution is added in time for neutralization, the neutralization temperature is controlled at 70, and the neutralization material takes pH 7.5 as the end point. in addition to
To remove the miscellaneous color, add activated carbon to neutralize 3/1000 of the material to decolorize, and then filter through vacuum suction to obtain a colorless and transparent sodium benzoate solution (content 50%).
Dry. The sodium benzoate solution is dried by drum drying or box-type spray drying to obtain a powdered product.