Kettle Saponification
- Kettle Saponification Type DVN
The SELA kettle process is applicable for the production of laundry soap as well as for high grade toilet soap. The production of toilet soap requires a period of 5 days.
Raw Materials
Fats, or oil (beef tallow, palm oil, coconut oil, palm kernel oil) are supplied in tank vehicles or in drums. Fat is discharged from the drums by melting with steam in a collecting vessel and transfe-red into storage tanks by a pump and kept at 75°C by heating.
Fats are saponified with caustic soda (32 - 36% NaOH) produced e.g. by dissolving crystalline caustic soda in water heated by direct steam injection. Lids and bottoms of drums are removed earlier.
The concentrated caustic soda lye is transferred by pump from the dissolving vessel to a dilution tank to adjust the concentration by adding water as needed. Saturated brine (21% NaCl) is produced by dissolving crystalline sodium chloride. The fat and caustic drums of about 200 kg are moved to the melting or dissolving stations by means of a lifting device and monorail trolley.
Saponification
- Boiling vat
The fat components needed for a kettle charge are supplied in feeding tanks located on top of the kettles. They are saponified in the kettle by continuous infeed of fat, soda lye and steam.
Glycerin washing with brine follows subsequently. If needed washing is done several times. After each washing step the soap has to settle for some hours to separate soap from lye. The lye is discharged afterwards. After glycerin washing, soap is fitted by adding a small amount of lye and by steam boiling and then has to settle 36 to 48 hours after the fitting operation. After settling the neat soap can be pumped from the upper kettle section to a storage tank. The niger can either be used for the next saponification or can be fed into a kettle after glycerin washing.
Spent Lye
Depending on the processing method a rate of 0.6 to 1.2 m3 spent lye/ton of soap with glycerin concentrations of 6 to 12% are produced. Glycerin recovery is possible by evaporation and distillation. Before this treatment the lye is cleaned, neutralized and the salt content of 8 to 10% has to be precipitated.
Standard Installations Type DVN for Production of Toilet Soap
| Neat Soap 62 % TFM (tons/day) | dried Soap 78 % TFM (kg/h) for 8h/day | Kettles Number x Capacity (m³) |
| 3 | 300 | 3 x 13 = 39 |
| 5 | 500 | 3 x 20 = 60 |
| 9 | 750 | 3 x 30 = 90 |
| 12 | 1000 | 4 x 30 = 120 |
| 15 | 1500 | 4 x 43 = 172 |
| 20 | 2000 | 4 x 60 = 240 |
| 34 | 3000 | 6 x 60 = 360 |
| 43 | 4000 | 4 x 120 = 480 |
| 52 | 5000 | 5 x 120 = 600 |
| 61 | 6000 | 6 x 120 = 720 |