- Acid treatment
- Alkaline treatment
- Evaporation of sweet water
- Crude glycerol distillation
- Distillation and deodorization of glycerin
- Treatment of glycerin distillation residue
(1) Acid treatment
The purpose of the acid treatment is to neutralize the free base in the sweet water and to decompose the fatty acid salt to produce fatty acids. The pH is about 3.5-4, and impurities such as fatty acids are removed by a separator. The reaction formula is as follows:
NaOH + HCl NaCl + H20
RCOONa + HCl RCOOH + NaCl
(2) Alkaline treatment
By adding a lye to maintain the pH of the solution at 8-9, some of the impurities in the sweet water are precipitated and removed.
(3) Evaporation of sweet water
Most of the water and crystalline salts are removed by an advanced evaporation process, yielding about 90% of crude glycerol.
(4) Crude glycerol distillation
The distillation of crude glycerol is performed at a high temperature of about 175°C, and the glycerol is converted into glycerol vapor by decompression and distilled together with the water. The glycerol product with a content of 99.8% can be obtained by three distillations and two advanced reflux distillation equipments. .
(5) Distillation and deodorization of glycerin
Deodorization is removed by vacuum extraction, and the decolorization process uses an internationally advanced fixed bed decolorization tower. The decolorization operation is generally controlled at a temperature of 80°C and a pressure of 0.35 MPa.
(6) Treatment of glycerin distillation residue
Glycerol was fully recovered by a Glycerine refining equipment (glycerol black skimmer kettle).