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		Soap Production (CDI, 1995, 70 p.)
			(introduction...)
			1. INTRODUCTION
			2. GENERAL INFORMATION ON SOAP
			3. THE RAW MATERIALS
			4. THE MANUFACTURE OF SOAP
			5. THE TREATMENT OF OILS AND FATS
			6. SAPONIFICATION: COLD PROCESS
			7. SAPONIFICATION: SEMI-BOILED PROCESS
			8. SAPONIFICATION: FULL BOILED PROCESS
			9. SAPONIFICATION: CONTINUOUS PROCESS
			10. THE COOLING AND DRYING OF SOAP
			11. FINISHING SOAP
			12. PRODUCTION OPTIONS
			13. GENERAL CONSIDERATIONS FOR MANUFACTURING PROCESSES
			14. CDI EXPERIENCE IN SOAP FACTORY PROJECTS
			15. IMPLEMENTING A SOAP FACTORY PROJECT
			16. EQUIPMENT MANUFACTURERS
			17. TURNKEY SUPPLIERS AND ENGINEERING OFFICES
			18. THE SOAP MAKERS
			19. DEVELOPING A SOAP FACTORY PROJECT
			20. CHECKLIST: RAW MATERIALS
			21. CHECKLIST: THE SOAP MARKET
			22. CHECKLIST: DATA FOR A FEASIBILITY STUDY
			ANNEXES
			23. SERVICES OFFERED BY THE CDI
			OTHER TITLES
			BACK COVER

9. SAPONIFICATION: CONTINUOUS PROCESS

A number of processes permit the continuous manufacture of neat soap with glycerine recovery. Generally speaking, these processes are based on a system of dosing pumps which continuously supply the saponification reactor with raw materials (fats, soda lye, electrolyte, water) in precisely specified proportions. This stage is followed by counter-current washing and separation (particularly by centrifugation) of the nigre (partly recycled) and the neat soap. These processes are largely fully automated and use vaporisation, pasting and other techniques in an appropriate reactor. The best-known processes are those used by Procter & Gamble, Monsavon, De Laval, Centripure, Mazzoni, Unilever, etc.

Some elements of continuous processes such as counter-current washing or centrifuge separation can be applied to batch processes, to accelerate the production cycles. Similarly, some techniques (pasting, for example) can skip the glycerine recovery stage and constitute interesting alternatives to continuous soap production in developing countries. These processes are tending to supersede the traditional full boiled process.

Continuous processes offer a speedy production cycle (a few hours), a saving of space and energy, and a reduction in loss and in requirements for skilled labour. Generally speaking, however, they are cost-effective only at production rates of 1 t/h or more (> 6,000 t/year), which necessitates a considerable initial investment. Furthermore, they require a high level of expertise in industrial and commercial management.